Datasheet MCP73831, MCP73832 (Microchip) - 17

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MCP73831/2 6.0 APPLICATIONS
followed by a constant voltage charging method. Figure 6-1 depicts a typical stand-alone application The MCP73831/2 are designed to operate in circuit, while Figure 6-2 and Figure 6-3 depict the conjunction with a host microcontroller or in a stand- accompanying charge profile. alone application. The MCP73831/2 provide the preferred charge algorithm for Lithium-Ion and Lithium- Polymer cells. The algorithm uses a constant current
Li-Ion Battery Charger
4 V 3 DD VBAT + Single CIN RLED COUT Li-Ion - Cell 5 STAT PROG REGULATED WALL CUBE LED RPROG 1 V 2 SS
MCP73831 FIGURE 6-1:
Typical Application Circuit.
6.0 120 6.0 600 ) 5.0 100 ) ) A ) 5.0 V 500 A (V 4.0 80 t (m e ( 4.0 400 t (m age n n lt ltag o 3.0 60 rre o 3.0 300 rre y V y V er 2.0 40 e Cu 2.0 200 e Cu MCP73831-2AC/IOT rg rg att a atter MCP73831-2AC/IOT a B 1.0 VDD = 5.2V 20 V Ch B 1.0 DD = 5.2V 100 R Ch PROG = 10 kΩ RPROG = 2 kΩ 0.0 0 0.0 0 0 20 40 60 80 0 100 120 140 160 180 30 60 90 120 150 180 210 240 Time (minutes) Time (minutes) FIGURE 6-2:
Typical Charge Profile
FIGURE 6-3:
Typical Charge Profile in (180 mAh Battery). Thermal Regulation (1000 mAh Battery).
6.1 Application Circuit Design
Due to the low efficiency of linear charging, the most 6.1.1.1 Current Programming Resistor important factors are thermal design and cost, which (RPROG) are a direct function of the input voltage, output current The preferred fast charge current for Lithium-Ion cells and thermal impedance between the battery charger is at the 1C rate, with an absolute maximum current at and the ambient cooling air. The worst-case situation is when the device has transitioned from the the 2C rate. For example, a 500 mAh battery pack has a preferred fast charge current of 500 mA. Charging at Preconditioning mode to the Constant-Current mode. this rate provides the shortest charge cycle times In this situation, the battery charger has to dissipate the maximum power. A trade-off must be made between without degradation to the battery pack performance or life. the charge current, cost and thermal requirements of the charger. 6.1.1 COMPONENT SELECTION Selection of the external components in Figure 6-1 is crucial to the integrity and reliability of the charging system. The following discussion is intended as a guide for the component selection process.  2005-2014 Microchip Technology Inc. DS20001984G-page 17 Document Outline MCP73831/2 Functional Block Diagram 1.0 Electrical Characteristics 2.0 Typical Performance Curves FIGURE 2-1: Battery Regulation Voltage (VBAT) vs. Supply Voltage (VDD). FIGURE 2-2: Battery Regulation Voltage (VBAT) vs. Ambient Temperature (TA). FIGURE 2-3: Output Leakage Current (IDISCHARGE) vs. Battery Regulation Voltage (VBAT). FIGURE 2-4: Charge Current (IOUT) vs. Programming Resistor (RPROG). FIGURE 2-5: Charge Current (IOUT) vs. Supply Voltage (VDD). FIGURE 2-6: Charge Current (IOUT) vs. Supply Voltage (VDD). FIGURE 2-7: Charge Current (IOUT) vs. Ambient Temperature (TA). FIGURE 2-8: Charge Current (IOUT) vs. Ambient Temperature (TA). FIGURE 2-9: Charge Current (IOUT) vs. Junction Temperature (TJ). FIGURE 2-10: Charge Current (IOUT) vs. Junction Temperature (TJ). FIGURE 2-11: Power Supply Ripple Rejection (PSRR). FIGURE 2-12: Power Supply Ripple Rejection (PSRR). FIGURE 2-13: Line Transient Response. FIGURE 2-14: Line Transient Response. FIGURE 2-15: Load Transient Response. FIGURE 2-16: Load Transient Response. FIGURE 2-17: Complete Charge Cycle (180 mAh Li-Ion Battery). FIGURE 2-18: Complete Charge Cycle (1000 mAh Li-Ion Battery). 3.0 Pin Description TABLE 3-1: Pin Function TableS 3.1 Battery Management Input Supply (VDD) 3.2 Battery Charge Control Output (VBAT) 3.3 Charge Status Output (STAT) 3.4 Battery Management 0V Reference (VSS) 3.5 Current Regulation Set (PROG) 3.6 Exposed Thermal Pad (EP) 4.0 Device Overview FIGURE 4-1: Flowchart. 4.1 Undervoltage Lockout (UVLO) 4.2 Battery Detection 4.3 Charge Qualification 4.4 Preconditioning 4.5 Fast Charge Constant-Current Mode 4.6 Constant-Voltage Mode 4.7 Charge Termination 4.8 Automatic Recharge 4.9 Thermal Regulation FIGURE 4-2: Thermal Regulation. 4.10 Thermal Shutdown 5.0 Detailed Description 5.1 Analog Circuitry 5.2 Digital Circuitry TABLE 5-1: Status Output 6.0 Applications FIGURE 6-1: Typical Application Circuit. FIGURE 6-2: Typical Charge Profile (180 mAh Battery). FIGURE 6-3: Typical Charge Profile in Thermal Regulation (1000 mAh Battery). 6.1 Application Circuit Design 6.2 PCB Layout Issues FIGURE 6-4: Typical Layout (Top). FIGURE 6-5: Typical Layout (Bottom). 7.0 Packaging Information 7.1 Package Marking Information Appendix A: Revision History Product ID System Trademarks Worldwide Sales