Battery Charger Basics


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To introduce basic knowledge of battery chargers and Microchip’s product portfolio

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Battery Charger Basics

  1. 1. Battery Charger Basics <ul><li>Source: M ICROCHIP </li></ul>
  2. 2. Introduction <ul><li>Purpose </li></ul><ul><ul><li>To introduce basic knowledge of battery chargers and Microchip’s product portfolio. </li></ul></ul><ul><li>Outline </li></ul><ul><ul><li>Definition of battery charger </li></ul></ul><ul><ul><li>Battery technical terms and chemistries </li></ul></ul><ul><ul><li>Applications </li></ul></ul><ul><ul><li>Microchip’s Charger Portfolio </li></ul></ul><ul><li>Content </li></ul><ul><ul><li>17 pages </li></ul></ul>
  3. 3. What is a Battery Charger? <ul><li>A battery charger is a device used to put energy into a secondary cell or (rechargeable) battery by forcing an electric current through it. </li></ul><ul><li>A good battery charger maximizes battery capacity, extends battery life and monitors the charging process </li></ul>
  4. 4. Battery Basics <ul><li>Theoretical Voltage (E 0 ) </li></ul><ul><ul><li>Determined by Type of Active Materials </li></ul></ul><ul><ul><ul><li>Volts (V) </li></ul></ul></ul><ul><li>Theoretical Capacity (Coulombic) </li></ul><ul><ul><li>Determined by Amount of Active Material </li></ul></ul><ul><ul><ul><li>ampere-hour (Ah) </li></ul></ul></ul><ul><li>Theoretical Energy </li></ul><ul><ul><li>Watthour (Wh) = </li></ul></ul><ul><ul><ul><li>voltage (V) x ampere-hour (Ah) </li></ul></ul></ul><ul><ul><li>Specific Energy (Watthours / gram) </li></ul></ul>
  5. 5. Battery Basics <ul><li>“ C” Rate </li></ul><ul><ul><li>I = M x Cn </li></ul></ul><ul><ul><li>Where: </li></ul></ul><ul><ul><ul><li>I = discharge current, A </li></ul></ul></ul><ul><ul><ul><li>C = numerical value of rated capacity, Ah </li></ul></ul></ul><ul><ul><ul><li>n = time, in hours, at which C is declared </li></ul></ul></ul><ul><ul><ul><li>M = multiple or fraction of C </li></ul></ul></ul><ul><li>Example </li></ul><ul><ul><li>1.7Ah Li-Ion Battery </li></ul></ul><ul><ul><li>1C Rate = 1.7A and 0.1C or C/10 Rate = 170 mA </li></ul></ul>
  6. 6. Battery Chemistries Primary Batteries Secondary Batteries Zinc Air NiCd Zinc Carbon NiMH Mercury Li-Ion Lithium Lead Acid Alkaline Rechargeable Alkaline
  7. 7. Applications <ul><li>Media players </li></ul><ul><li>GPS </li></ul><ul><li>Keyboards/Mice </li></ul><ul><li>Bluetooth devices </li></ul><ul><li>Power Tools (drills, etc.) </li></ul><ul><li>Wireless headsets </li></ul><ul><li>Toothbrushes </li></ul><ul><li>Shavers </li></ul>
  8. 8. Important Features Summary <ul><li>Charging Current </li></ul><ul><li>Charging Voltage </li></ul><ul><li>Charging Voltage Accuracy </li></ul><ul><li>Internal/External FET </li></ul><ul><li>Dual-input </li></ul><ul><li>Load-sharing </li></ul><ul><li>Overvoltage Protection </li></ul><ul><li>Shutdown Controls </li></ul>
  9. 9. Charge Voltage and Accuracy
  10. 10. Microchip’s Charger Portfolio <ul><li>Integrated chargers for Li-Ion/Li-Polymer/Lithium Iron Phosphate batteries </li></ul><ul><ul><li>Fastest growing chemistry (high energy density per size) </li></ul></ul><ul><ul><li>Formable into custom shapes </li></ul></ul><ul><ul><li>Most consumer electronics use these chemistry </li></ul></ul><ul><li>NiCd and NiMH chemistries supported through PIC+MCP1630/1 solutions </li></ul>
  11. 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. 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. 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. 14. Battery Charger Features <ul><li>Internal/External FET </li></ul><ul><ul><li>Integrated Pass Transistors allows smaller solution size. </li></ul></ul><ul><ul><li>External Pass Transistors allow more flexibility in charger design </li></ul></ul><ul><li>Dual-input </li></ul><ul><ul><li>MCP73837/8 or MCP73871 allow two types of power sources, such as USB and AC/DC </li></ul></ul><ul><ul><li>Allows two different charging profiles depending on the power source </li></ul></ul>
  15. 15. Battery Charger Features <ul><li>Integrated System Load Sharing and Battery Charge Management </li></ul><ul><ul><li>Simultaneously Power the System and Charge the Li-Ion Battery </li></ul></ul><ul><ul><li>Ensures system load has priority over Li-Ion battery charge current </li></ul></ul><ul><li>Overvoltage Protection </li></ul><ul><ul><li>In case of a voltage spike on the input, the charger shuts down to prevent damage to self or the device </li></ul></ul>
  16. 16. Battery Charger Features <ul><li>Shutdown Controls </li></ul><ul><ul><li>Thermistor Input - Allows to monitor the temperature of battery cells and shutdown charging in case of overheating </li></ul></ul><ul><ul><li>Timers – allow to shutdown charging after a predetermined amount of time </li></ul></ul><ul><ul><li>Automatic-shutdown – stops charging once the battery voltage reaches predetermined set point </li></ul></ul><ul><ul><li>UVLO (Under Voltage Lockout) – prevents charger from operating if input voltage is too low </li></ul></ul>
  17. 17. Additional Resource <ul><li>For ordering MCP73xxx Battery Chargers, please click the part list or </li></ul><ul><li>Call our sales hotline </li></ul><ul><li>For more product information go to </li></ul><ul><ul><li>Microchip Battery Chargers </li></ul></ul><ul><li>Visit Element 14 to post your question </li></ul><ul><ul><li> </li></ul></ul><ul><li>For additional inquires contact our technical service hotline or even use our “Live Technical Chat” online facility </li></ul>Newark Farnell