A battery charger is a device that puts energy into a rechargeable battery by forcing an electric current through it. The document discusses battery charger basics including definitions, battery chemistries, applications, and Microchip's portfolio of battery charger integrated circuits. Microchip offers various single-cell and dual-cell battery charger ICs supporting lithium-ion, lithium polymer, and lithium iron phosphate batteries with integrated or external MOSFETs and features like overvoltage protection and temperature monitoring.

1. Battery Charger Basics Source: M ICROCHIP

2. Introduction Purpose To introduce basic knowledge of battery chargers and Microchip’s product portfolio. Outline Definition of battery charger Battery technical terms and chemistries Applications Microchip’s Charger Portfolio Content 17 pages

3. What is a Battery Charger? A battery charger is a device used to put energy into a secondary cell or (rechargeable) battery by forcing an electric current through it. A good battery charger maximizes battery capacity, extends battery life and monitors the charging process

4. Battery Basics Theoretical Voltage (E 0 ) Determined by Type of Active Materials Volts (V) Theoretical Capacity (Coulombic) Determined by Amount of Active Material ampere-hour (Ah) Theoretical Energy Watthour (Wh) = voltage (V) x ampere-hour (Ah) Specific Energy (Watthours / gram)

5. Battery Basics “ C” Rate I = M x Cn Where: I = discharge current, A C = numerical value of rated capacity, Ah n = time, in hours, at which C is declared M = multiple or fraction of C Example 1.7Ah Li-Ion Battery 1C Rate = 1.7A and 0.1C or C/10 Rate = 170 mA

6. Battery Chemistries Primary Batteries Secondary Batteries Zinc Air NiCd Zinc Carbon NiMH Mercury Li-Ion Lithium Lead Acid Alkaline Rechargeable Alkaline

7. Applications Media players GPS Keyboards/Mice Bluetooth devices Power Tools (drills, etc.) Wireless headsets Toothbrushes Shavers

8. Important Features Summary Charging Current Charging Voltage Charging Voltage Accuracy Internal/External FET Dual-input Load-sharing Overvoltage Protection Shutdown Controls

9. Charge Voltage and Accuracy

10. Microchip’s Charger Portfolio Integrated chargers for Li-Ion/Li-Polymer/Lithium Iron Phosphate batteries Fastest growing chemistry (high energy density per size) Formable into custom shapes Most consumer electronics use these chemistry NiCd and NiMH chemistries supported through PIC+MCP1630/1 solutions

11. Battery Charger Offering MCP73123 OVP MCP73842/4 12V input MCP73862/4 1A, 12 V input MCP73213 OVP MCP73861/3 1A, 12 V input MCP73833/4 1A, 10-MSOP MCP73837/8 USB & AC-adapter MCP73871 Load Sharing MCP73113/4 5.8/6.5V OVP MCP73853/5 0.5A, USB MCP73831/2 0.5A, SOT-23 MCP73811/2 0.5A, SOT23,USB MCP73223 OVP Linear Li-Ion/Li-Polymer Battery Chargers 1-cell 2-cell 500 mA 1A Int. FET MCP73826/7/8 Basic features MCP73841/3 Mult. features 12 V input Ext. FET Int. FET Ext. FET 1-cell Int. FET 2-cell LiFePO 4 Battery Chargers Int. FET

12. Battery Charger Portfolio – Single-cell * See MCP7383X Li-Ion System Power Path Management Reference Design ** LiFePO4 battery chemistry Vcc Range (V) Vreg (V) FET Icharge Load sharing Dual Input Temp Mon. OVP MCP73841/3 4.5-12 4.1, 4.2 External - - - Yes - MCP73831/2 3.75-6 4.20, 4.35, 4.40, 4.50 Internal 500 mA ext* - - - MCP73833/4 3.75-6 4.20, 4.35, 4.40, 4.50 Internal 1A ext* - Yes - MCP73837/8 3.75-6 4.20, 4.35, 4.40, 4.50 Internal 1A ext* Yes Yes - MCP73871 4.4-6 4.10, 4.20, 4.35, 4.40 Internal 1A Yes Yes Yes - MCP73113/4 4-16 4.10, 4.20, 4.35, 4.40 Internal 1.1A - - - 6.5V/5.8V MCP73123** 4-16 3.6 Internal 1.1A - - - 6.5V MCP73861/3 4.5-12 4.1, 4.2 Internal 1.2A - - Yes -

13. Battery Charger Portfolio – Dual-cell * LiFePO4 battery chemistry Vcc Range (V) Vreg (V) FET Icharge Temp Monitor OVP MCP73842/4 4.5-12 8.2, 8.4 External - Yes - MCP73213 4-16 8.2, 8.4, 8.7, 8.8 Internal 1.1A - 13V MCP73223* 4-16 7.2 Internal 1.1A - 13V MCP73862/4 4.5-12 8.2, 8.4 Internal 1.2A Yes -

14. Battery Charger Features Internal/External FET Integrated Pass Transistors allows smaller solution size. External Pass Transistors allow more flexibility in charger design Dual-input MCP73837/8 or MCP73871 allow two types of power sources, such as USB and AC/DC Allows two different charging profiles depending on the power source

15. Battery Charger Features Integrated System Load Sharing and Battery Charge Management Simultaneously Power the System and Charge the Li-Ion Battery Ensures system load has priority over Li-Ion battery charge current Overvoltage Protection In case of a voltage spike on the input, the charger shuts down to prevent damage to self or the device

16. Battery Charger Features Shutdown Controls Thermistor Input - Allows to monitor the temperature of battery cells and shutdown charging in case of overheating Timers – allow to shutdown charging after a predetermined amount of time Automatic-shutdown – stops charging once the battery voltage reaches predetermined set point UVLO (Under Voltage Lockout) – prevents charger from operating if input voltage is too low

17. Additional Resource For ordering MCP73xxx Battery Chargers, please click the part list or Call our sales hotline For more product information go to Microchip Battery Chargers Visit Element 14 to post your question www.element-14.com For additional inquires contact our technical service hotline or even use our “Live Technical Chat” online facility Newark Farnell