Analog and Interface Solutions Portable Power Conversion Design Guide www.microchip.com/analog

Design Guide Introduction and Contents Portable power conversion applications present unique and challenging design considerations. Innovative, small electronics require solutions with small footprints. In order to maintain battery life, portable applications require both high conversion efficiency and low standby power dissipation. Multi-cell battery packs may require step-down (buck) conversions and single cell batteries often require step-up (boost) conversions to maintain consistent power levels while the batteries discharge. Some products require constant voltage regulation for microcontrollers, sensors or RF signal processing; while some circuits need constant current regulation for backlighting or battery charging. Microchip offers a broad array of solutions which feature small package sizes, high-efficiency, low standby power, accuracy and versatility solutions to solve these portable power conversion challenges. Table of Contents Step-Down (Buck) Switch Mode Power Converters .......................2 Linear (Low Drop Out) Regulators ..................................9 Step-Up (Boost) Switch Mode Power Converters .......................12 Backlighting Solutions with Switching Regulators ......................17 Backlighting Solutions with Charge Pump DC/DC Converters ..............19 Linear Battery Chargers ........................................20 Programmable Battery Chargers ..................................22 Application Notes and Demonstration Boards .........................24 DC/DC Conversion Step-Down (Buck) Switch Mode Power Converters Step-Down (Buck) Switch Mode Power Converters For wide input range voltage sources and high output current applications switch-mode power converters offer a significant increase in efficiency compared to linear regulators. This results in longer battery run time in portable applications. Step-down or buck converters are used to regulate an output voltage that is always lower than the source voltage. Using inductors and capacitors for energy storage allows buck converters to commonly be more than 90% efficient, and under some circumstances they can be more than 95% efficient. Microchip offers a wide selection of buck converters and PWM controllers. Many of them are specifically designed to convert power from NiMH, Ni-Cd, Li-Ion, Alkaline multi-cell or 12/24V SLA batteries. Converters integrate power MOSFET switches used to commutate the supply current, while controllers rely on external power MOSFETs in diodes to switch the converter current. Synchronous converters rely on two MOSFETs working together to control the current flow, while asynchronous converters replace one MOSFET with a freewheeling power diode. Synchronous converters deliver higher efficiency for low output voltages, especially less than 3.3V, while asynchronous converters work well for higher output voltages. 2 Portable Power Conversion Design Guide

DC/DC Conversion Step-Down (Buck) Switch Mode Power Converters MCP16301/H 36V Input Voltage Non-Synchronous Buck Converter The MCP16301 is a highly integrated, high-efficiency, fixed-frequency, step-down DC-DC converter in a popular 6-pin SOT-23 package. This converter operates from voltage sources up to 30V, including the integrated high-side switch, fixed-frequency Peak Current Mode Control, internal compensation, peak current limit and over-temperature protection. This device allows you to build DC/DC conversion circuits with minimal external components. ■ 12V and 24V industrial/SLA ■ Integrated 460 mΩ n-channel ■ Internal soft-start battery input DC-DC conversion buck switch ■ Cycle-by-cycle peak current limit ■ Up to 96% typical effi ciency ■ 600 mA output current ■ Under voltage lockout (UVLO) at 3.5V ■ Wide input voltage range: ■ 500 kHz fi xed frequency ■ Extended −40 to +125°C operating •   4.0V to 30V (MCP16301) ■ Adjustable output voltage temperature range •   4.7V to 36V (MCP16301H) ■ Low device shutdown current ■ Over-temperature protection ■ Output voltage range: 2.0V to 15V ■ Peak current mode control ■ D2PAK package linear regulator ■ 2% output voltage accuracy ■ Internal compensation replacement ■ Stable with ceramic capacitors ■ Available in 6-pin SOT-23 package Example MCP16301 Non-Synchronous Buck Regulator Application Circuit 1N4148 CBOOST 100 nF VIN BOOST 15L μ1H VOUT 4.5V to 30V 3.3V @ 600 mA VIN SW 40V CIN Schottky COUT 10 µF Diode 31.2 kΩ 2 × 10 μF EN VFB GND 10 kΩ Typical MCP16301 Power Conversion Effi ciency MCP16301 Light Load Operation with a Fixed 5.0V Output 100 V = 6V IN 90 %) 80 VIN = 12V cy ( 70 VIN = 30V n e ci 60 Effi 50 VOUT = 5.0V 40 IL 30 0 100 200 300 400 500 600 I (mA) OUT 3 Portable Power Conversion Design Guide

DC/DC Conversion Step-Down (Buck) Switch Mode Power Converters MCP16311/2 30V Input, High-Efficiency, Integrated Synchronous Buck Regulator The MCP16311 is a compact, high-efficiency, fixed-frequency PWM/PFM, synchronous step-down DC-DC converter in a 8-pin MSOP or 2 × 3 TDFN package that operates from input voltage sources up to 30V. Integrated features include a high- side and a low-side switch, fixed-frequency Peak Current Mode Control, internal compensation, peak-current limit and over- temperature protection. The MCP16311 provides all the active functions for local DC-DC conversion, with fast transient response and accurate regulation. ■ Up to 95% efficiency ■ Automatic pulse-frequency ■ Internal soft-start: 300 μs turn on ■ Wide 4.4V to 30V input modulation/pulse-width modulation ■ Peak current mode control voltage range (PFM/PWM) operation (on ■ Cycle-by-cycle peak current limit ■ Wide 2.0V to 24V output MCP16311), or 500 kHz PWM only ■ Under-voltage lockout voltage range operation (on MCP16312) (UVLO) at 3.6V (typical) with ■ Integrated high-performance ■ Low 3 μA (typical) device 0.5V of hysteresis n-channel low- and high-side shutdown current ■ Thermal shutdown at 150°C, with switches: 170 mΩ low-side MOSFET, ■ Low 44 μA device quiescent current 25°C hysteresis 300 mΩ high-side MOSFET (when not switching in PFM Mode) ■ Stable 0.8V reference voltage ■ Internal compensation Example MCP16311 Synchronous Buck Regulator Application Circuit CBOOST 100 nF VIN BOOST 15 Lμ1H VOUT 4.5V to 30V 3.3V @ 1A VIN SW CIN COUT 2 ×10 µF 31.2 kΩ 2 × 10 μF EN VFB VCC 10 kΩ CvCC GND 1 µF MCP16311 Ouput Current Capability Typical MCP16311 Efficiency, with and without V PFM Operation Enabled 1600 V = 3.3V 100 1400 OUT V = 5V 90 V O U T = 5V OUT 1200 80 V O U T = 3 .3V 1000 V =12V %) 70 mA)800 OUT cy ( 60 I(OUT600 Efficien 4500 400 30 200 20 VIN = 12V PWM ONLY 10 0 PWM/PFM 0 5 10 15 20 25 30 0 V (V) 1 10 100 1000 IN I (mA) OUT 4 Portable Power Conversion Design Guide

DC/DC Conversion Step-Down (Buck) Switch Mode Power Converters MCP16311 12V Buck-Boost Application Some power supplies require the ability step the voltage up or down from the input to the output. This is particularly useful in battery-powered applications where the battery voltage may be above or below the desired output voltage, depending on the type of battery used or battery charge remaining. By adding a few additional circuit components, the MCP16311 can be adapted to work in a buck-boost topology that would address this issue. The application can either buck or boost the input voltage in order to maintain the output voltage, operating from a 6V to 18V input and providing up to 300 mA of output current. MCP16311 Buck-Boost Application Circuit REN 1 MΩ EN BOOST L1 D1 SW VIN = 4.5V to 1C180V1 µF C102 µF VIN R566 μH G D 3Q4010VV n S-Cchhoatntknye lD iode 1C03 µF C104 µF R14B0 kΩ VOUT VCC FB 4.7Ω S MOSFET RT GND 10 kΩ CVCC 1 µF AGND PGND GND1 5 Portable Power Conversion Design Guide

DC/DC Conversion Step-Down (Buck) Switch Mode Power Converters MCP16323 3A Synchronous Buck DC/DC Converter The MCP16323 is a fully integrated synchronous buck dc/dc converter that operates from 6V to 18V input, regulates the output voltage to any level between 0.9V to 5V, and supplies load currents up to 3A. Operating at a fixed 1 MHz switching frequency offers small external inductor and capacitor sizes, minimizing board space. Integrating both high- and low-side switches results in a compact, high-efficiency converter circuit. The device is available in a 3 × 3 mm QFN package with exposed pad to reduce the thermal resistance from junction to case. With both adjustable and fixed output voltage options, this device provides flexibility for generating custom output voltages or minimizing external resistor dividers and obtaining fixed output voltages. The internal peak current mode control architecture results in fast transient response, minimizing the change in output voltage with dynamic load conditions. Small ceramic capacitors are used at the input and output for space-constrained applications. ■ Up to 95% typical efficiency ■ Integrated 120 mΩ n-channel low- ■ Under-voltage lockout (UVLO) ■ Wide 6.0V to 18V input side switch at 5.75V voltage range ■ 1 MHz fixed frequency operation ■ Over-temperature protection ■ 3A output current with pulse skipping for efficient ■ Over-voltage protection will tri-state ■ Multiple fixed output voltage options: operation in light load conditions the SW outputs to prevent damage 0.9V, 1.5V, 1.8V, 2.5V, 3.3V, 5.0V ■ Low device shutdown current if the output exceeds 103% of the with 2% output voltage accuracy ■ Peak current mode control regulation voltage ■ Adjustable version output voltage ■ Internal compensation ■ Vout voltage status reported with range: 0.9V to 5.0V with 1.5% ■ Stable with ceramic capacitors the power good output pin reference voltage accuracy ■ Internal soft-start ■ Available in 16-pin QFN (3 × 3 mm) ■ Integrated 180 mΩ n-channel ■ Cycle-by-cycle peak current limit package with exposed thermal pad high-side switch MCP16323 Typical Application Circuit Typical MCP16323 Efficiency with a 5V Fixed Output CBOOST 100 6V.I0NV to 18V BOOST 22 nF 4.7L 1μH V3.O3UVT @ 3A 95 VIN= 6V VIN SW 90 2 ×10 CµIFN VFB C2 O×U 2T2 μF %) 85 VIN= 18V VIN= 12V ( 80 VOUT y c 75 n EN 10 kΩ cie 70 PG Effi 65 VOUT= 5V SGND PGND 60 55 50 0.0 0.6 1.2 1.8 2.4 3.0 I (A) OUT 6 Portable Power Conversion Design Guide

DC/DC Conversion Step-Down (Buck) Switch Mode Power Converters MCP1603/L/B Synchronous Buck Regulators The MCP1603 is a family of highly efficient, fully integrated 500 mA synchronous buck regulators. The 2.7V to 5.5V input range makes these ideally suited for battery powered applications, including one-cell Li-ion; two- or three-cell NiMH; or two- or three-cell NiCd power sources. With heavy loads, the MCP1603/L operates in a 2.0 MHz fixed frequency PWM mode which provides a low-noise, low output voltage ripple, small-footprint solution. With light loads, the MCP1603/L automatically changes operation to a PFM mode to minimize quiescent current consumption, improving battery run time. These two modes allow the MCP1603/L to achieve the best possible efficiency over the entire load current range. The MCP1603B, in contrast, only switches in PWM mode, maintaining a low output voltage ripple over a wide output load range in noise-sensitive applications (audio or RF). Only three additional external components are required for a complete converter solution when using the fixed voltage options, or a flexible output voltage can be produced with a resistive divider on the adjustable output device options. The low-profile, small-footprint packages also enable the system solution to be achieved with minimal size. ■ Typical efficiency over 90% ■ Automatic PWM to PFM mode transitions (MCP1603/L) ■ Supplies up to 500 mA of output current or PWM only operation (MCP1603B) ■ Low 45 μA typical PFM quiescent current ■ 100% duty cycle operation ■ Low 0.1 μA typical shutdown current ■ Internally compensated ■ Adjustable output voltage range: 0.8V to 4.5V ■ Under-voltage lockout (UVLO) at 2.3V ■ Fixed output voltage options: 1.2V, 1.5V, 1.8V, ■ Over-temperature protection 2.5V, and 3.3V ■ Space-saving 5-lead TSOT and 8-pin 2 × 3 DFN ■ 2.0 MHz operation packages MCP1603 Typical Application Circuit Typical MCP1603 Efficiency V2.I0NV to 5.5V 4.7 μH V1.O5UVT @ 500 mA 100 VIN LX 90 V = 3.6V 4.7 μH 4.7 μF 80 IN %)70 ( SHDN y 60 c n50 V = 4.2V e IN VOUT fici40 GND EfE 30 V = 3.3V OUT 20 PFM/PWM PWM Only 10 0 0.1 1 10 100 1000 Output Current (mA) 7 Portable Power Conversion Design Guide

DC/DC Conversion Step-Down (Buck) Switch Mode Power Converters Input Output Control Device Output Voltage Voltage Features Packages Scheme Range (V) Range (V) 2 MHz operation, UVLO, PFM/PWM PFM/PWM Fixed or (MCP1603/L) or PWM only (MCP1603B) 5-pin TSOT, 8-pin MCP1603/B/L 2.7–5.5 0.8–4.5 or PWM Adjustable mode, over-temperature protection, low 2 × 3 DFN Only quiescent current, low shutdown current UVLO, over-temperature protection, output Fixed or short circuit protection, power good output, 10-pin DFN, TC1303A/B/C 2.7–5.5 0.8–4.5 PFM/PWM Adjustable independent shutdown, synchronous buck 10-pin MSOP and LDO combination device UVLO, over-temperature protection, output Fixed or short circuit protection, power-good output, 10-pin DFN, TC1304 2.7–5.5 0.8–4.5 PFM/PWM Adjustable synchronous buck and LDO combination, 10-pin MSOP sequenced startup and shutdown UVLO, output short circuit protection, Fixed or 10-pin DFN, TC1313 2.7–5.5 0.8–4.5 PFM/PWM over-temperature protection, independent Adjustable 10-pin MSOP shutdown for buck and LDO outputs Asynchronous, internal compensation, UVLO, 500 kHz operation, low output ripple, MCP16301 Adjustable 4–30 2–15 PWM 6-pin SOT-23 over-temperature protection, extended temperature rating Asynchronous, internal compensation, UVLO, 500 kHz operation, low output ripple, MCP16301H Adjustable 4.7–36 2–15 PWM 6-pin SOT-23 over-temperature protection, extended temperature rating Synchronous, internal compensation, UVLO, PFM/PWM 500 kHz operation, low output ripple, 8-pin MSOP, 8-pin MCP16311/2 Adjustable 4.4–30 2–24 or PWM over-temperature protection, extended 2 × 3 TDFN Only temperature rating 1A or 2A, synchronous, internal Fixed or compensation, UVLO, 1 MHz operation, power MCP16321/2 6–24 0.9–5 PWM 16-pin 3 × 3 QFN Adjustable good output, over-temperature protection, extended temperature rating 3A, synchronous, internal compensation, Fixed or UVLO, 1 MHz operation, power good output, MCP16323 6–18 0.9–5 PWM 16-pin 3 × 3 QFN Adjustable over-temperature protection, extended temperature rating 8 Portable Power Conversion Design Guide

DC/DC Conversion Linear Regulators Linear Regulators Linear regulators provide a precise regulated voltage to the system load from a varying input voltage source. Compared to switching regulators, they are generally smaller, simpler, and can benefit from reduced electrical noise. They are generally less efficient than buck regulators, but for small voltage changes or low currents the absolute power losses may be small. There are trade-offs when selecting the proper LDO. Regulation tolerance, dropout voltage, power supply ripple rejection (PSRR), dynamic performance, quiescent current, power dissipation capability and protection features can be important device capabilities. Microchip’s LDO product line can address a wide input voltage range with some LDOs capable of withstanding 40V transients. We offer devices that consume ultra-low power with input quiescent currents as low as 20 nA; disable load circuits for low-power standby operation using shutdown inputs; filter noisy inputs with PSRR as high as 90 dB; and enjoy robust operation with integrated over-current protection, short-circuit protection, high-temperature operation capabilities, and over-temperature protection features. MCP1703A Low Quiescent Current 16 V Low Dropout Linear Regulator The MCP1703A is a CMOS, low dropout voltage regulator with 250 mA maximum output current. Working with voltages up to 16V and consuming only 2 µA of quiescent current, it is an ideal solution for applications using 9V alkaline, Li-ion, or multi-cell power sources. It is available in space-efficient SOT-23A and SOT-89 packages; or in a thermally capable 3-pin SOT-223 and 8-pin 2 × 3 DFN. ■ Wide 2.7V to 16V input operating voltage range ■ 0.4% Typical output voltage tolerance ■ Supports load currents up to 250 mA ■ Many standard output voltage options: 1.2V, 1.5V, 1.8V, ■ Low 2.0 μA typical quiescent current 2.5V, 2.8V, 3.0V, 3.3V, 4.0V, 5.0V ■ Low ground current when operating in dropout ■ Stable with 1.0 μF to 22 μF ceramic output capacitance ■ Fast startup time ■ Short-circuit protection ■ Low dropout voltage, 625 mV typical ■ Over-temperature protection @ 250 mA for VR = 2.8V MCP1703A Typical Application Circuit VOUT VIN 3.3V VIN VOUT IOUT CIN 50 mA 9V 1 μF Battery Ceramic COUT 1 μF Ceramic GND 9 Portable Power Conversion Design Guide

DC/DC Conversion Linear Regulators MCP1710 Ultra-Low Quiescent Current LDO Regulator The MCP1710 is low dropout (LDO) linear regulator that provides up to 200 mA of current to the load while maintaining an ultra-low 20 nA of quiescent current consumption, and it comes in a tiny 2 × 2 DFN package. ■ Ultra-low 20 nA (typical) quiescent current ■ Standard output voltages: 1.2V, 1.8V, 2.5V, 3.3V, 4.2V ■ Ultra-low 0.1 nA typical shutdown supply current ■ Low 450 mV (maximum) dropout voltage at 200 mA ■ 200 mA output current capability for Vout < 3.5V ■ Stable with a 1.0 µF ceramic output capacitor ■ 100 mA output current capability for Vout > 3.5V ■ Over-current protection ■ Wide 2.5V to 5.5V input operating voltage range ■ Space-saving, 8-lead plastic 8-pin 2 × 2 VDFN package MCP1710 Typical Application Circuit VIN VOUT COUT CIN MCP1710 SHDN FB GND MCP1755 300 mA, 16V, High-Performance LDO The MCP1755 and MCP1755S are 16V, high PSRR voltage regulators with short-circuit current fold-back. These regulators provide up to 300 mA of output current and accept a continuous input voltage from 3.6V to 16V, making them ideal for automotive and commercial 12V DC systems. Delivering 80 dB of ripple rejection at 1 kHz, these devices are ideal for AC-sensitive applications like GFCI and AFCI circuit breaker designs. The current fold-back feature gradually reduces the device current down to 30 mA under short-circuit conditions to protect against damage. When the short is removed, the device will recover and continue operating. ■ High noise rejection, typical PSRR 80 dB at 1 kHz ■ Tight output tolerance ±2.0 % over entire operating ■ Low 68 µA typical quiescent current temperature range ■ Wide 3.6V to 16.0V input operating voltage range ■ Stable with minimum 1.0 µF output capacitance ■ Supplies up to 300 mA output current for all ■ Power good output output voltages ■ Shutdown input ■ Low 300 mV typical dropout voltage with a 300 mA load ■ Short-circuit protection with true output current fold-back ■ High output accuracy, 0.85% typical output range ■ Over-temperature protection ■ Standard output voltage options: 1.8V, 2.5V, 2.8V, 3.0V, 3.3V, 4.0V, 5.0V MCP1755 Typical Application Circuit CIN VIN 12V 1 μF Ceramic MCP1755S GND VOUT VOUT 5.0V COUT IOUT 1 μF 30 mA Ceramic 10 Portable Power Conversion Design Guide

DC/DC Conversion Linear Regulators Output Output Typical Typical Dropout Max. Input Device Voltage Current Quiescent Voltage at Max. Features Packages Voltage (V) Range (V) (mA) Current (μA) Iout (mV) 3-pin SOT-23A, Shutdown, power good MCP1700 6.0 1.2–5.0 250 1.6 178 3-pin SOT-89, output with adjustable delay 3-pin TO-92 3-pin SOT-23A, Low quiescent current, low 3-pin SOT-89, MCP1703A 16 1.2–5.0 250 2 625 ground current in dropout 3-pin SOT-223, 8-pin 2 × 3 DFN MCP1710 5.5 1.2–4.2 200 0.02 450 Ultra low quiescent current 8-pin 2 × 2 DFN Shutdown, power good 8-pin 2 × 3 DFN, MCP1725 6.0 0.8–5.0 500 120 210 output with adjustable delay 8-pin SOIC Shutdown, power good 8-pin 2 × 3 DFN, MCP1726 6.0 0.8–5.0 1000 140 250 output with adjustable delay 8-pin SOIC Shutdown, power good 8-pin 2 × 3 DFN, MCP1727 6.0 0.8–5.0 1000 140 330 output with adjustable delay 8-pin SOIC 5-pin SOT-23, Shutdown, power good, high 3-pin SOT-223, MCP1754 16 1.8–5.0 150 56 300 PSRR, true current fold-back 3-pin SOT-89, protection 8-pin 2 × 3 DFN 3-pin SOT-23A, High PSRR, true current 3-pin SOT-89, MCP1754S 16 1.8–5.0 150 56 300 fold-back protection 3-pin SOT-223, 8-pin 2 × 3 DFN 5-pin SOT-23, Shutdown, power good, high 3-pin SOT-223, MCP1755 16 1.8–5.0 300 68 300 PSRR, true current fold-back 3-pin SOT-89, protection 8-pin 2 × 3 DFN 3-pin SOT-23A, High PSRR, true current 3-pin SOT-89, MCP1755S 16 1.8–5.0 300 68 300 fold-back protection 3-pin SOT-223, 8-pin 2 × 3 DFN 3-pin SOT-23A, 3-pin SOT-89, MCP1804 28 1.8–18 150 50 1300 Shutdown 5-pin SOT-89, 8-pin 2 × 3 DFN 5-pin SOT-223, MCP1824 6.0 0.8–5.0 300 120 200 Shutdown, power good 5-pin SOT-23 TC1016 6.0 1.8–3.0 80 50 150 Shutdown 5-pin SC-70 5-pin SC-70, TC1017 6.0 1.8–4.0 150 53 285 Shutdown SOT-23A 11 Portable Power Conversion Design Guide

DC/DC Conversion Step-Up (Boost) Switch Mode Power Converters Step Up (Boost) Switch Mode Power Converters Boost converters increase the unregulated input voltage to a regulated output (unlike buck converters, which always reduce the input voltage). Conceptually, both types of circuits use switched electromagnetic components to store energy and maintain efficiency. Boost converters are commonly used in single- and two-cell Alkaline, NiMH and new non-rechargeable lithium battery applications. Microchip offers several boost converter solutions with integrated MOSFETs that are capable of starting and operating from a single-cell battery (0.8V input, or less in some cases). Many devices offer pulse width modulation (PWM) and pulse frequency modulation (PFM) modes of operation. PWM mode switches at constant frequency to minimize output ripple and noise while delivering high-efficiency power conversion at high output loads. PFM mode dynamically reduces the switching frequency, sometimes even allowing increased the output ripple, in order to dramatically reducing switching losses and improve efficiency in light load conditions. Taking advantage of these functions, the MCP1640 and MCP16251/2 device families (and many other Microchip parts) can automatically transition between PFM and PWM as the output current demand changes. In some applications, the output ripple introduced by PFM mode may be too noisy for the desired circuit performance. For these designs, the MCP1640B device can operate in PWM mode only, providing a low output ripple voltage and reducing electrical noise. Many of these boost regulators can be disabled with a shutdown input signal; several are available with true load disconnect (open the circuit from input to output) or with bypass (connected input and output) operation during shutdown. Integrated boost converters are small-footprint, high-efficiency power conversion solutions for many portable applications. MCP16251 Ultra-Low Quiescent Current, PFM/PWM Synchronous Boost Regulator with True Output Disconnect or Input/Output Bypass Options One of the advantages of the MCP16251/2 over other boost regulators is its low quiescent current (4 µA). This, combined with the PFM mode operation and a high resistance feedback voltage divider, results in a converter that greatly increases the run time of battery-powered applications at low load. ■ Typical efficiency up to 96% ■ Adjustable output from 1.8V to 5.5V ■ High current output: ■ 1.23V feedback voltage •   Iout > 100 mA at Vout = 3.3V and Vin = 1.2V ■ Automatic PFM/PWM operation: •   Iout > 250 mA at Vout = 3.3V and Vin = 2.4V •   500 kHz PWM operation •   Iout > 225 mA at Vout = 5.0V and Vin =3.3V •   100 mV typical PFM output ripple ■ Ultra-low device quiescent current: ■ Internal synchronous rectifier •   Output quiescent current less than 4 µA typical ■ Internal compensation (device is not switching, Vout > Vin) ■ Inrush current limiting •   Input sleep current less than 1 µA ■ Internal soft-start (1.5 ms typical) (device is not switching, Vout > Vin, no load) ■ Selectable, logic-controlled shutdown states: •   Typical no load input current of 14 µA •   True load disconnect option (MCP16251) (device is switching) •   Input to output bypass option (MCP16252) •   0.6 µA typical shutdown current ■ Anti-ringing control ■ Low 0.82V start-up voltage ■ Over-temperature protection ■ Low 0.35V minimum operating input voltage ■ Available in 6-lead SOT-23 and 8-lead 2 × 3 TDFN ■ Maximum input voltage ≤ Vout < 5.5V packages MCP16251 Typical Application Circuit MCP16251 Typical Circuit Efficiency L1 100 4.7 μH 95 V = 3.0V IN 90 V0.I9NV TO 1.7V VIN SW VOUT V3.O3UVT ncy (%)8805 VIN= 1.5V VIN= 2.4V e75 CIN 1.69 MΩ ci 4.7 μF Effi70 VFB COUT 65 10 μF EN 60 1 MΩ 55 V = 3.3V OUT 50 GND 0.1 1 10 100 1000 I (mA) OUT 12 Portable Power Conversion Design Guide

DC/DC Conversion Step-Up (Boost) Switch Mode Power Converters MCP1640 High Performance PFM/PWM Synchronous Boost Converter with True Output Disconnect or Input/Output Bypass Options The MCP1640 is a compact, high-efficiency, fixed-frequency, synchronous step-up DC-DC converter. It provides an easy-to-use power supply solution for applications powered by one-, two-, or three-cell alkaline, NiCd, NiMH; one-cell Li-ion; or one-cell Li-polymer batteries. It provides very high efficiency through integration of the low-resistance n-channel boost switch and synchronous p-channel switch, and is available with PFM/PWM, PWM only, true load disconnect or bypass options. ■ Typical efficiency up to 96% ■ Selectable, logic-controlled, shutdown states: ■ High current output: •   True load disconnect option (MCP1640/B) •   Iout > 100 mA at Vout = 3.3V and Vin = 1.2V •   Input to output bypass option (MCP1640C/D) •   Iout > 350 mA at Vout = 3.3V and Vin = 2.4V ■ Low < 1 μA shutdown current (all states) •   Iout > 350 mA at Vout = 5.0V and Vin =3.3V ■ Low 19 μA typical device quiescent current ■ Low 0.65V typical start-up input voltage ■ Internal synchronous rectifier (3.3V Vout at 1 mA) ■ Internal compensation ■ Low 0.35V typical operating input voltage ■ Inrush current limiting (3.3V Vout at 1 mA) ■ Internal soft-start ■ Wide 2.0V to 5.5V adjustable output voltage range ■ Low noise, anti-ringing control ■ Maximum input voltage ≤ Vout < 5.5V ■ Over-temperature protection ■ High frequency 500 kHz PWM operation, with PFM and ■ Available in 6-lead SOT-23 and 8-lead 2 × 3 PWM device options: DFN packages •   Automatic PFM/PWM operation (MCP1640/C) •   PWM only, PFM operation disabled (MCP1640B/D) MCP1640 Application Circuit Using a Single Cell MCP1640 Application Circuit Using a Single Cell Alkaline Battery Li-ion Battery L1 L1 4.7 μH 4.7 μH SW SW VOUT V0.I9NV TO 1.7V VIN VOUT 3.3V @ 100V OmUAT V3.I0NV TO 4.2V VIN VOUTS 5.0V @ 300 mA CIN 976 kΩ 4C.I7N μF VOUTP 976 kΩ 4.7 μF VFB COUT VFB COUT 10 μF 10 μF EN EN 309 kΩ 562 kΩ PGND SGND GND MCP1640 Typical Efficiency for a 3.3V Output 100 90 VIN = 2.5V 80 %) 70 cy ( 60 VIN = 0.8V VIN = 1.2V n 50 e ci 40 Effi 30 20 10 V = 3.3V OUT 0 0.01 0.1 1 10 100 1000 I (mA) OUT 13 Portable Power Conversion Design Guide

DC/DC Conversion Step-Up (Boost) Switch Mode Power Converters Performance Tradeoffs – Matching the Boost Converter to the Load Requirements In many cases, light or no load conditions have very different requirements than high load conditions. This tradeoff can be readily observed by comparing the MCP1640 and MCP16251. The MCP1640 offers higher current capability, handing peak loads up to 350 mA compared to only 225 mA for MCP16251. However, the MCP16251 reduces the input quiescent current drawn from the battery even further than the MCP1640, and the MCP16251 PFM mode offers higher efficiency at light load conditions. An 80% quiescent current reduction extends battery run time for applications that operate for long periods of time in sleep mode. When powering a 100 µA load, the MCP16251 is nearly 12% more efficient than the MCP1640. Applications that draw high currents may need the additional power capability of the MCP1640, while applications with significant operating time at low or no load conditions may benefit from the reduced power consumption of the MCP16251. No Load Input Current Requirements for MCP1640 Light Load Efficiency of MCP1640 and MCP16251 and MCP16251 100 100 90 )90 VOUT= 3.3V A µ80 )%) 8800 VVIINN==22.55VV ent (70 cy ( 70 VOUT= 3.3V r nn Cur60 MCP1640 cie 60 ut 50 Effi 5500 p40 MCP16251/2 n d I30 40 MCP1640 aa Lo20 MCP16251/2 30 No 10 0.01 0.1 1 10 100 1000 0 IOUT(mA) 1 1.2 1.4 1.6 1.8 2 2.2 2.4 Input Voltage (V) 14 Portable Power Conversion Design Guide

DC/DC Conversion Step-Up (Boost) Switch Mode Power Converters AAAA Battery Boost Circuit An MCP1640 boost converter and PIC12F microcontroller can create a simple power solution which will deliver a 3.3V output from a single alkaline battery cell, with very low power consumption and long battery run time, especially in low- current applications. The circuit will run in standby mode, with the PIC12F617 in sleep mode and the MCP1640 disabled, consuming only a few μA from the battery (in shutdown mode the MCP1640 typically consumes 0.75 μA). A charged capacitor will maintain the output until the comparator on the PIC® microcontroller detects a low voltage. If the output capacitor voltage drops too far, the PIC microcontroller will turn on the MCP1640, which will operate normally until the output capacitor is charged, and then the microcontroller will disable the boost converter again. When the MCP1640 is in normal operating mode, the no load input current is approximately 70 μA at 1.5V input. By pulsing the MCP1640’s enable at low frequency, this method reduces the average input current by up to 80%. This circuit is implimented in the MCP1640 Single Quadruple-A Battery Boost Converter Reference Design, available through Microchip. MCP1640 Single Quadruple-A Battery Boost MCP1640 Boost Converter Reference Coverter Demonstration Board (MCP1640RD-4ABC) Design Circuit Single Quadruple-A Battery Input Load Switch VIN P-MOS VOUT MCP1640 A/D EN I/O VDD Load ON/OFF S1 I/O 1 2 I/O I/O PIC12F617 LED Status MCP1640 Boost Converter Reference Design MCP1640 Boost Converter Reference Design No Behavior During Operation Load Input Current 30 ut p n ad IA) 25 oµ o Lnt ( 20 Ne y urr dbC 15 n a St 10 0.8 1 1.2 1.4 1.6 Input Voltage (V) * 15 Portable Power Conversion Design Guide

DC/DC Conversion Step-Up (Boost) Switch Mode Power Converters Input Output Control Device Output Voltage Voltage Features Packages Scheme Range (V) Range (V) 425 mA peak current limit, 500 kHz synchronous operation, PFM/PWM PFM/PWM (MCP1624) or PWM only (MCP1623) mode 6-pin SOT-23, 0.35/ MCP1623/4 Adjustable 2–5.5 or PWM switching operation, internal compensation, 8-pin 2 × 3 0.65–5.0 Only over-temperature protection, 19 µA quiescent TDFN current, < 1 µA shutdown current, true output disconnect 650 mA peak current limit, 500 kHz synchronous operation, internal compensation, over-temperature protection, 6-pin SOT-23, 0.35/ MCP16251/2 Adjustable 1.8–5.5 PFM/PWM 4 µA quiescent current, 0.6 µA shutdown 8-pin 2 × 3 0.82–5.0 current, true output disconnect (MCP16251) TDFN or input to output bypass (MCP16252) options, ± 3% output accuracy 800 mA peak current limit, 500 kHz synchronous operation, internal PFM/PWM compensation, over-temperature protection, 6-pin SOT-23, 0.35/ MCP1640/B/C/D Adjustable 2–5.5 or PWM 19 µA quiescent current, < 1 µA shutdown 8-pin 2 × 3 0.65–5.0 Only current, true output disconnect (MCP1640/B) TDFN or input to output bypass (MCP1640C/D) options, ± 3% output accuracy 16 Portable Power Conversion Design Guide

Backlighting Solutions Switching Regulators Switching Regulators Efficient backlighting in portable applications presents a number of unusual power supply design challenges. Like all portable circuits as in all portable designs, board area is at a premium and minimizing power consumption is essential for maximizing battery run time. Commonly, LED forward voltages are unique potentials within the circuit; they may be higher or lower than the battery voltage, and different from the voltages needed to power the microcontrollers and peripheral components. In addition, since the current flow through LEDs is exponentially dependent on voltage, brightness control and LED longevity both require accurate, measured and controllable current delivery. LED Backlighting with MCP1643: Synchronous Boost Constant Current Regulator MCP1643 is a compact, high-efficiency, fixed-frequency, synchronous step-up LED driver with constant current that can operate from one- and two-cell alkaline, NiMH and NiCd batteries. With an output of up to 5V, the device can drive a single white or blue LED; or pairs of red, green, and yellow LEDs connected in series. In addition, the 550 mA load current capability is enough to drive high-brightness LEDs with high current requirements, or sets of matched LEDs connected in parallel. Current is read from the voltage on a low-impedance sense resistor connected to the feedback pin, with minimal power losses compared to other current measurement techniques. For visible blinking or dimming, the enable pin can be toggled with a PWM signal to switch the power supply and LED load on and off. (At frequencies approximately 50 Hz or faster the blinking light should appear dimmed, and not visibly flickering.) Finally, the over-voltage protection feature limits the output to 5V, protecting the power circuit in the event of an open circuit or load failure. ■ Constant current drive capability with a low component ■ Low 1.2 µA shutdown current count, area-efficient circuit ■ Over-voltage protection halts device operation (floating ■ 1 MHz PWM synchronous boost operation with up to output) if the LED fails or is disconnected 550 mA output current ■ Up to 90% efficiency ■ Low-voltage reference input to maximize LED efficiency ■ 240 µs soft start time conversion (VFB = 120 mV) ■ Available in tiny footprint 8-lead 2 × 3 DFN or 8-pin ■ Capable of start up with only 0.65V input, and MSOP packages continuous operation with an input above 0.5V MCP1643 LED Drive Application with a Single LED MCP1643 LED Output Current as a Function of L1 Input Voltage and Sense Resistor 4.7 μH 500 SW I ILLEEDD == 250R .m1S2EATV mA)440500 LED VF= 3.5V @ IF= 700 mAR SET= 0.25Ω VIN VOUT ent (330500 RSET= 0.41Ω CIN LED Curr250 4.7...10 μF D 200 VFB C4.O7U μTF LE150 R SET= 0.82Ω EN RSET 100 R SET= 1.2Ω ON 4.7 Ω 50 RSET= 5Ω OFF 0 GND 0.6 0.9 1.2 1.5 1.8 2.1 2.4 Input Voltage (V) MCP1643 LED Drive Application with Multiple Parallel LEDs L1 4.7 μH 0.12V ILED = RSET SW Battery input ILED = 50 mA (One or Two Cells) VZ = 2.4V ILED2 = 50 mA ILED3 = 50 mA VIN VOUT WLED1 DZ WLED2 WLED3 CIN 4.7...10 μF D VFB COUT 4.7 μF EN RSET R2 R3 ON 2.4 Ω 2.4 Ω 2.4 Ω OFF GND 17 Portable Power Conversion Design Guide

Backlighting Solutions Switching Regulators MCP16312 Buck Converter LED Application The MCP16312 buck converter can be used as a constant current source to drive one or more LEDs. Starting from the standard buck circuit, the anode of the LED load is connected at the buck coverter output. Using a sense resistor between the LED cathode and ground will produce a constant voltage at constant current, and this voltage can be used as the feedback signal into the buck converter. The control loop in the MCP16312 will adjust the duty cycle of the internal MOSFETs, regulating to a constant voltage on the sense resistor, corresponding to a constant output current in the LED string. MCP16312 Buck Converter LED Application Circuit CBOOST 0.1 μF BOOST L1 VIN = 12V 15 μH ILED = 400 mA VIN SW CIN 1 × White COUT 2 ×10 μF EN LED 2 ×10 μF REN VFB 1 MΩ VCC RB = 2Ω 1C VμCFC R B = IVLEFBD GND ´ MCP16301 Cuk LED Application While it is typically operated as a buck regulator, the MCP16301 can be creatively designed into a low component count C´uk circuit. It will operate from 6 V to 18 V in, producing a regulated output and supplying up to 300 mA of current. This is an excellent solution for LED drive applications, capable of driving multiple LEDs in series (up to 15V). Due to both the low number of components (as few as eleven) and readily available small size surface mount component options (mostly 0603 surface mount packages), this design can be implemented in a very small board area. This circuit is implemented in the MCP16301 High Voltage Single Inductor C´uk LED Demo Board, available through Microchip. MCP16301 C´uk Converter Circuit 1N4148 CBOOST 100 nF VIN BOOST 33 μH 6V to 18V VIN SW 4.7 μF 0.47 μF 40V EN −VOUT Schottky Diode VFB GND 2.7Ω 150 kΩ −VOUT 2.2 nF 18 Portable Power Conversion Design Guide

Backlighting Solutions Charge Pump DC/DC Converters Charge Pump DC/DC Converters The MCP1256, MCP1257, MCP1258 and MCP1259 are inductorless, positive regulated charge pump DC/DC converters. Generating a regulated 3.3V output voltage from a 1.8V to 3.6V input, they are specifically designed for applications operating from two-cell alkaline, two-cell Ni-Cd, two-cell Ni-MH, or one primary lithium coin cell battery. These devices automatically switch from 1.5× to 2× boost operation modes to maintain high efficiency. In addition, at light output loads the MCP1256 and MCP1257 can be placed in a sleep mode, lowering the quiescent current while maintaining the regulated output voltage. Alternatively, the MCP1258 and MCP1259 provide a bypass feature connecting the input voltage to the output. This allows for real-time clocks, microcontrollers or other system devices to remain biased with virtually no current being consumed by the MCP1258 or MPC1259. In normal operation, the charge pumps switch at a fixed 650 kHz, avoiding sensitive IF bands, and the output voltage ripple is below 20 mV at load currents up to 100 mA. The MCP1256 P-P and MCP1258 feature a power-good output that can be used to detect out-of-regulation conditions. The MCP1257 and MCP1259 feature a low battery indication that issues a warning if the input voltage drops below a preset voltage threshold. Extremely low supply current and few external parts (4 capacitors) make these devices ideal for small, battery powered applications. A Shutdown mode is also provided for further power reduction. The devices incorporate thermal and short-circuit protection. ■ High accuracy 3.3V ± 3.0% output voltage ■ Operates at 650 kHz switching frequency ■ Accepts 1.8V to 3.6V input voltages ■ Low-power sleep mode feature on MCP1256/7 ■ Supplies up to 100 mA output current ■ Bypass mode on MCP1258/9 ■ Low 20 mV output voltage ripple ■ Low-power 0.1 μA shutdown mode P-P ■ Integrated thermal shutdown and short circuit ■ Shutdown input compatible with 1.8V logic protection ■ Soft-start circuitry to minimize inrush current ■ Uses small ceramic capacitors ■ Available in 10-pin 3 × 3 DFN or 10-pin MSOP packages MCP1259 Charge Pump Backlighting Circuit MCP1259 Power Conversion Effi ciency VIN BOOST VOUT 1.6V to 3.6V 3.3V VIN VOUT COUT C10IN μF R1 10 μF SHDN LBO Low Battery Indicator C1+ C2+ C1 C2 1 μF 1 μF C1– C2– ON OFF BYPASS GND 19 Portable Power Conversion Design Guide

Battery Management Linear Battery Chargers Linear Battery Chargers In battery-powered systems, the quality of the charging circuit plays a key role in the life and reliability of the battery. Microchip offers a complete line of linear Li-Ion battery chargers. To further reduce design size, cost and complexity, the Li-Ion Charge Management Controllers provide a reliable, low-cost and high accuracy voltage regulation solution with few external components. The MCP73830L Li-Ion linear charger was developed specifically for low-charge current applications. Charge currents as low as 20 mA can be controlled using a programmable resistor. Single- and two-cell LiFePO4 batteries can be charged using the MCP738123/213 linear chargers. In order to supply world-class portable devices, most of Microchip’s Li-Ion/LiFePO4 Battery Management Controllers are equipped with thermal regulation, reverse discharge protection, safety charge timer and integrated current sensing. The programmable constant charge current can assist you in meeting different application requirements with a single resistor. Along with their small physical size, the low number of external components required makes Microchip’s battery management ICs ideally suited for portable applications. MCP73830 Single Cell, Li-Ion/Li-Polymer Batter Charge Management Controllers The MCP73830 battery chargers contain a large number of features for creating long life, long run time, fast charging battery circuits. Including options for battery preconditioning, programmable charge currents, end-of-charge thresholds and elapse timers, these charging devices maximize fuel capacity and minimize charge time while maintaining battery life in low-component-count, small-area circuits perfectly suited for portable applications. ■ Complete linear charge management controller ■ Soft start to minimize inrush current ■ High 0.75% accuracy preset voltage regulation ■ Fixed 0 to 4 hour elapse timer ■ Programmable charge current: ■ Available in options for 7.5% or 10% current thresholds •   100 mA to 1A for MCP73830 to trigger automatic end-of-charge termination •   20 mA to 100 mA for MCP73830L ■ Chip enable input (CE) ■ Available with or without a preconditioning mode, ■ Under-voltage lockout (UVLO) which decreases charge current to 10% of the ■ Automatic power-down typical current when the battery voltage is below the ■ Integrated thermal regulation preconditioning threshold ■ Wide −40°C to +85°C operating temperature range ■ Available with or without a fixed 1 hour preconditioning ■ Available in small footprint 6-pin TDFN timer to stop the charge cycle when the battery is not (2 × 2 × 0.75 mm) packages charging properly Typical Application Circuit for the MCP73830L (Low Current, 20 to 200 mA) and MCP73830 (High Current, 100 mA to 1A) Battery Charger Solutions VDD VBAT Regulated 4.7 μF 4.7 μF wall cube 1-Cell STAT PROG Li-Ion 1 kΩ Battery 2 kΩ LO HI CE VSS 20 Portable Power Conversion Design Guide

Battery Management Linear Battery Chargers MCP73113, MCP73123: Battery Charge Management Controllers In addition to the features of the MCP73830, these battery chargers also include charge status outputs, over-voltage protection and more options for end-of-charge thresholds, safety timers and charge currents. Also available are the MCP73213 (Li-ion) and MCP73223 (LiFePO4), with higher voltage capabilities to charge two cells in series. ■ Programmable charge current: 130 mA to 1.1A ■ Charge status output ■ Selectable 5%, 7.5%, 10% or 20% automatic end-of-charge ■ Elapse safety timer: 4 hour, 6 hour, 8 hour or disable ■ Over-voltage protection ■ Available in 10-pin 3 × 3 DFN packages Typical Application Circuit for the MCP73123 (LiFePO4) and MCP73113 (Li-ion) Battery Chargers VDD VBAT Regulated CIN VDD VBAT COUT wall cube LiFePO 4 Battery STAT PROG RLED VSS RPROG VSS Selected Products: Integrated FET Linear Battery Charger Device Family Cells Vcc Range (V) Features MCP73XXX 1/2 4–16 Li-Ion and LiFePO4, High Current, 0.5% Voltage Reg. MCP73811/2 1 3.75–6 USB Selectable Charge Current, Thermal Reg. Programmable Charge Current, Thermal Reg., UVLO, Preconditioning MCP73831/2/3/4 1 3.75–6 and End-of-Charge MCP73837/8 1 3.7–6 Dual Input (USB, DC, Adapter), Auto Input Switchover MCP73871 1 3.9–6 Integrated System Load Sharing and Battery Charge Management 21 Portable Power Conversion Design Guide

Battery Management Programmable Battery Chargers MCP19111 Switching Battery Charger Circuit Designs for wide input range, high output power multi-chemistry battery chargers are used for many battery-powered applications. The MCP19111 programmable battery charger reference design operates from an input range of 6V to 28V and can be configured to charge NiMH, Li-Ion and LiFeO4 batteries in multiple series and parallel configurations. The reference design uses the MCP19111 Digitally Enhanced Power Analog PWM controller to step down higher input voltages to lower output voltage while regulating the current or voltage to properly charge the selected battery chemistry. A graphical user interface (GUI) is configured prior to starting the charge profile for the desired battery load. Once configured, the MCP19111 flash memory stores the charge settings for subsequent charge cycles. Simplified MCP19111 Programmable Multi-Chemistry Battery Charger +VIN GND VIN J3 VSENSE ICSP A = 1 ½ MCP6072 +VDD J2 HDRV PICkit™ Serial BOOT PHASE GPIO +VBATT +ISENSE Temp_Sense GPIO –ISENSE –VBATT VDD LDSRV A = 40 VDR GND IBATT-SENSE ½ MCP6072 MCP19111 Features ■ Single channel ■ Vin Range: 4.5V to 32.0V ■ Integrated, synchronous MOSFET driver: •   Logic-level drive (5V) •   2A source/4A sink drive current ■ Fully programmable (12F core) •   MPLAB® X IDE support, GUI-configurable •   4 k word Flash, 256b RAM •   Internal, adjustable analog compensation •   Adjustable deadtime/current limit/UVLO/OVLO/… •   Configurable switching frequency: 100 kHz to 1.2 MHz •   Up to 12 general purpose I/O •   PMBus/I2C™ communication interface ■ Master/slave synch frequency ■ Available in 28-lead 5 × 5 mm QFN 22 Portable Power Conversion Design Guide

Battery Management Programmable Battery Chargers MCP1631 Switching Battery Charger Circuit The MCP1631 Analog PWM Controller with integrated ×10 current sense amplifier, Battery Voltage Divider Buffer Amplifier, MOSFET driver, high-speed Over Voltage Detection and Pulse Width Modulation controller, combined with a PIC microcontroller, is used to develop intelligent battery chargers. The combination of the dedicated analog PWM controller with a PIC MCU creates highly versatile charging solutions. The MCP1631HV provides the analog circuitry needed to drive several power train topologies (SEPIC, Flyback, Boost) while the PIC MCU is used to develop the programmable charge algorithm to adapt to the number of series batteries and their chemistry. The block diagram below represents a SEPIC solution used to charge NiMH or Li-Ion batteries. MCP1631HV SEPIC Programmable Multi-Chemistry Battery Charger +VIN GND +VDD J5 ICSP OSC +VBATT Temp_Sense PIC® MCU MCP1631HV –VBATT VREF STATUS VDD Li-Ion VEXT VBATT VBATT CS NiMH OV OV VFS GND LED 1...4 MCP1631 Features ■ High-speed analog PWM controller (2 MHz operation) ■ External reference input sets regulation voltage ■ Can pair with a microcontroller for “Intelligent” power or current system development ■ Error amplifier, battery current ISNS amplifier, battery ■ Peak current mode control (MCP1631/MCP1631HV) voltage VSNS amplifier integrated ■ Voltage mode control (MCP1631V/MCP1631VHV) ■ Integrated over-voltage comparator ■ High voltage options operate to +16V input: ■ Integrated high current low side MOSFET driver (1A peak) •   MCP1631HV current mode ■ Shutdown mode reduces Iq to 2.4 µA (typical) •   MCP1631VHV voltage mode ■ Internal over-temperature protection ■ Regulated output voltage options: ■ Under-voltage lockout (UVLO) •   +5.0V or +3.3V ■ Available in 20-lead 4 × 4 mm QFN (MCP1631/ •   250 mA maximum current MCP1631V only), 20-lead TSSOP or 20-lead SSOP ■ External oscillator input sets switching frequency and maximum duty cycle limit 23 Portable Power Conversion Design Guide

Related Support Material Application Notes AN1156: Battery Fuel Measurement Using Delta-Sigma ADC Devices The following application notes are available on the Microchip web site: www.microchip.com. The fuel used (mAH) and fuel remaining (mAH) in a battery can be calculated by tracking the discharging and charging AN793: Power Management in Portable currents over time. This application note describes the use Applications: Understanding the Buck Switch Mode of ADC devices to perform these functions. Power Converter AN1311: Single-Cell Input Boost Converter Design This is an in-depth application note describing the design of buck topology switch mode power supplies for use in A variety of single-cell input synchronous boost converters portable applications. can be designed using the MCP1640B/C/D family of devices. This document shows different performance AN947: Power Management in Portable Applications: tradeoffs and features present in these designs. Charging Lithium-Ion/Lithium-Polymer Batteries AN1337: Optimizing Battery Life in DC Boost This application note focuses on the fundamentals Converters Using MCP1640 of charging Lithium-Ion/Lithium-Polymer batteries, including a linear, stand-alone solution utilizing This application note details practical considerations for Microchip’s MCP73841. efficient circuit operation using the MCP1640 device in applications intended for long battery life. AN960: New Components and Design Methods AN1385: Using the MCP16301 Design Analyzer Bring Intelligence to Battery Charger Applications The MCP16301 design analyzer provides efficiency and Leveraging the benefits of digital and mixed-signal power stability information for the power supply designs using the supply designs, this application note describes solutions MCP16301 buck converter. for intelligent battery charger designs capable of handing battery removal, reverse polarity, short circuits and other AN1541: Using the MCP19111 Design Tools situations. This application note covers battery reference material, basic switch mode power supply converter trade- The MCP19111 offers incredible flexibility for advanced offs, and a complete battery charger system design with power supply designs. This document illustrates a fuel gauge. design example using MCP19111 design tools to unlock the unique features of the digitally enhanced power AN968: Simple Synchronous Buck Regulator – analog controller. MCP1612 MCP19111 – Buck Power Supply, Graphical User This application note contains all of the information Interface User’s Guide needed to design a synchronous buck converter using the MCP1612, including an implemented design example with This guide discusses the MPLAB X IDE plug-in software measured power conversion results. available to help program the MCP19111 for customized buck topology power supply designs. AN1088: Selecting the Right Battery System for Cost-Sensitive Portable Applications This application note describes design tradeoffs in battery chemistry, charging, product cost and product size, including application examples. 24 Portable Power Conversion Design Guide

Related Support Material Evaluation Boards MCP1630 NiMH Battery Charger Demonstration Board (MCP1630DM-NMC1) Microchip offers a number of boards to help evaluate device families. Contact your local Microchip sales office The MCP1630 is interfaced to the for a demonstration. PIC16LF818 to develop a fault-tolerant NiMH battery charger with fuel gauge AAAA Clock Demo capability using a 1 MHz SEPIC converter. A PIC microcontroller performs basic clock functions on a LCD display using a single AAAA battery boosted up to 3.3V using a MCP1624. The demo includes capacitive MCP1630V Bi-directional Four-Cell Li-Ion Charger touch controls and battery fuel measurement. Reference Design (MCP1630RD-DDBK3) MCP1252 Charge Pump Backlight Demonstration The MCP1630V is set up to boost a Board (MCP1252DM-BKLT) low source voltage to charge four Li-Ion series cells, or current can be reversed The MCP1252 charge pump is set up for to provide regulated output from the Four- biasing backlighting or driving other LED cell Li-Ion battery pack to other circuits. applications, with intensity, dimming and disabling features. MCP1630 Li-Ion Multi-Bay Battery Charger Reference Design (MCP1630RD-LIC1) MCP1602 Evaluation Board (MCP1602EV) This circuit is capable of charging two single-cell Li-Ion The board evaluates the PFM and PWM battery packs in parallel utilizing an input voltage of 10V to operation of the MCP1602 buck regulator 30V, providing a constant current—constant voltage charge step down the input voltage, with with preconditioning, cell temperature monitoring and selectable output voltages. battery pack fault monitoring. MCP16301 High-Voltage Buck-Boost Demo Board (ADM00399) MCP16251 and MCP1640B Synchronous Boost Converters Evaluation Board (ADM00458) Using small surface-mount components in a minimal board area, this board is Two boost converters are available, with selectable output designed to operate from a 5V to 30V voltage levels and enable/disable capability. input and regulate the output to 12V. MCP16301 5V/600mA Low Noise Evaluation Board (ADM00433) MCP1631HV Digitally-Controlled Programmable The MCP16301 boost converter runs at Current Source Reference Design high frequency to obtain a high efficiency (MCP1631RD-DCPC1) 5V regulated output with minimal radiated noise for use in sensitive applications. The MCP1631HV is set up in a SEPIC power converter which, combined with a PIC16F616 microcontroller, can function as a current source for driving LEDs in multiple MCP1630 Boost Mode LED Driver Demo Board series or parallel configurations, charging (MCP1630DM-LED2) NiMH, NiCd, and Li-ion batteries. The MCP1630 takes an input voltage MCP1631HV Multi-Chemistry Battery Charging between 9 and 16V DC, and boosts it Reference Design (MCP1631RD-MCC2) to provide a constant 350 or 700 mA (selectable) current for powering up to a Using a PIC16F883 microcontroller in 30W string of LEDs. combination with the MCP1631HV high- speed analog PWM controller, this design can charge one to five NiMH or NiCd batteries; one- or two-cell Li-Ion batteries; or drive one or two 1W LEDs. 25 Portable Power Conversion Design Guide

Related Support Material MCP16323 Evaluation Board (ADM00427) MCP19111 Evaluation Board (ADM00397) This small footprint, high-current-density buck circuit The MCP19111 evaluation board provides up to 3A at 3V from an input voltage between demonstrates the MCP19111 operation 6.0 and 18V. in a synchronous buck topology. Nearly all operation and control parameters are MCP1640 12V/50 mA Two Cells Input Boost programmable using the integrated PIC Converter Reference Design (ARD00386) microcontroller core. Using inputs between 2.0 and 5.0V MCP3421 Fuel Gauge Demo Board typical of a two-cell battery pack, this MCP1640 boost converter can generate (MCP3421DM-BFG) high 9, 12 or 24V outputs. Measures and displays battery voltage, discharge current, usage for non- rechargeable batteries, and can be MCP1640 Single Quad-A Battery Boost Converter programmed to additionally recharge Reference Design (MCP1640RD-4ABC) and calculate the remaining usage for a rechargeable Li-Ion battery. This design uses a single quad-A battery and boosts the 1.5V input to a 3.3V output, including an enable feature to MCP73113 OVP Single Cell Li-Ion Battery Charger greatly reduce the standby current consumption. Evaluation Board (MCP73113EV-1SOVP) MCP1640 Sync Boost Converter Evaluation Board This design charges a Li-Ion battery at (MCP1640EV-SBC) 500 mA or 1000 mA. It includes LED status indicators, precondition, termination, Using input voltages between 0.35V and and auto-recharge features, at a fixed 5.5V, the MCP1640 generates either a 2.0, 4.20V output. 3.3 or 5.0V regulated output (provided the input voltage is below the output voltage). MCP73871 Demo Board with Voltage Proportional Current Control (MCP73871DM-VPCC) When the input voltage is present, the MCP73871 board can charge a single-cell Li-Ion or Li-polymer battery MCP1643 Synchronous Boost LED Constant while powering a load, or when the Current Regulator Evaluation Board (ADM00435) input voltage is removed, it can power Powered by one-cell or two-cell the load from the battery. The circuit Alkaline, NiCd or NiMH batteries, features input current limits, constant current/constant the MCP1643 is used in a compact, voltage charging and LED indicators for charge status. high-efficiency, fixed-frequency, step- up DC/DC converter optimized as an LED constant current MCP73X23 OVP Lithium Iron Phosphate Battery generator, with a minimum number of external components Charger Evaluation Board (MCP73X23EV-LFP) for applications. This board contains two circuits: an MCP73123 design to charge a single-cell LiFePO4 battery and a MCP73223 MCP19035 600 kHz Synchronous Buck Controller implementation to charge a dual-cell LiFePO4 battery. Evaluation Board (ADM00445) This is a compact, highly efficient, MCP73837/8 AC/USB Dual-Input Battery Charger step-down voltage regulator that will Evaluation Board (MCP7383XEV-DIBC) convert the input voltage rail (typically Using the minimum number of 12V) to a regulated 1.8V output voltage components, this complete battery with 10A of current. charge management circuit automatically selects between AC-adapter or USB-port power sources. 26 Portable Power Conversion Design Guide

Related Support Material Also Check the Following Demonstration Boards on Our Website MCP16301 High-Voltage UCS1001 Evaluation Board Single-Inductor C´uk LED Driver (ADM00540) Demo Board (ARD00410) UCS1002 Programmable USB Port MCP1632 300 kHz Boost Power Evaluation Board Converter Demo Board (ADM00497) (ADM00530) MCP1256/7/8/9 Charge Pump MCP1710 Demo Board Evaluation Board (ADM00468) (MCP1256/7/8/9EV) MCP1601 Buck Regulator MCP73213 OVP Dual-Cell Li-Ion Evaluation Board (MCP1601EV) Battery Charger Evaluation Board (MCP73213EV-2SOVP) MCP1602 Evaluation Board MCP73831 Evaluation Kit (MCP1602EV) (MCP73831EV) MCP1612 Synchronous Buck MCP73833 Li-Ion Battery Charger Regulator Evaluation Board Evaluation Board (MCP73833EV) (MCP1612EV) MCP7383X Li-Ion System Power MCP1630 Low-Cost Li-Ion Battery Path Management Reference Charger Reference Design Design (MCP7383XRD-PPM) (MCP1630RD-LIC2) MCP73871 Evaluation Board (MCP73871EV) MCP16301 High Voltage Buck- Boost Demo Board (ADM00399) 27 Portable Power Conversion Design Guide

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