STD1LNK60Z-BASED CELL PHONE BATTERY CHARGER DESIGN



Category: Telephone, cellular phone and intercom
Manufacture: ST Microelectronics, Inc.
Datasheet: Download this application note


Description:
AN2228 APPLICATION NOTE
STD1LNK60Z-based Cell Phone Battery Charger Design
This application note is a Ringing Choke Converter (RCC)-based, step-by-step cell phone battery charger design procedure. The RCC is essential to the self-oscillating fly-back converter, and operates within the Discontinuous Conduction Mode (DCM) and Continuous Conduction Mode (CCM) boundaries without noticeable reverse recovery of the output rectifying diodes. RCC control is achieved by using discrete components to control the peak current mode, so the overall RCC cost is relatively low compared to the conventional Pulse Width Modulation (PWM) IC fly-back converter. As a result, RCC is widely used for low power applications in industry and home appliances as a simple and cost-effective solution. Figure 1. STD1LNK60Z-based RCC Printed Circuit Board
AN2228 - APPLICATION NOTE
1 Power Transformer Design Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1 .1 1 .2 1 .3 1 .4 1 .5 1 .6 1 .7 1 .8 1 .9 Switching Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 STD1LNK60Z MOSFET Turn Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Primar y Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Primar y Inductance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Magnetic Core Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Primar y Winding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Secondary Winding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Auxiliary Winding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Gap Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
STD1LNK60Z-based RCC Control Circuit Components . . . . . . . . . . . . . 12
2 .1 2 .2 2 .3 2 .4 2 .5 2 .6 2 .7 MOSFET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 R3 Startup Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Optocoupler Power Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 R7 Sense Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Constant Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Zero Current Sense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Constant Voltage And Constant Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Test Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Appendix A: STD1LNK60Z-based RCC Circuit Schematics . . . . . . . . . . 22 Appendix B: STD1LNK60Z-based RCC Circuit Bill of Materials . . . . . . . 23
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

 
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