器件名称: DI-78
功能描述: Low Cost 1.6 W CV/CC Charger/Adapter
文件大小: 458.3KB 共2页
简 介:Design Idea DI-78 LinkSwitch-HF Low Cost 1.6 W
CV/CC Charger/Adapter
Application Charger/Adapter Device LNK353 Power Output 1.6 W Input Voltage 85-265 VAC Output Voltage 5.2 V Topology Flyback
Design Highlights
Low cost, low component count solution No-load power consumption <300 mW – meets worldwide energy efciency requirements Low leakage current design, <10 A Universal AC input range – single design worldwide Secondary-side feedback gives accurate voltage and constant current output Small size and weight Meets EN55022 B EMI limits
through the use of transformer shield windings, a snubber (R4 and C9) across the output diode, and by the internal switching frequency jitter of LinkSwitch-HF. LinkSwitch-HF uses ON/OFF control to regulate the output. Current >49 A fed from the BYPASS pin capacitor C5 into the FEEDBACK pin disables the MOSFET for that switching cycle. To maximize efciency, a Schottky diode (D7) is used to rectify the secondary. Filtering is provided by a low ESR capacitor C6 and for most battery chargers, no additional ltering is required. During CV operation the output voltage is determined by the sum of the Q1 VBE voltage and VR1. As the voltage increases above this level, Q1 is biased on and current is fed through the optocoupler LED, thus inhibiting switching cycles to maintain regulation. The transition to CC operation occurs when the voltage developed across R9 and R8 exceeds the LED forward voltage of U2 (~1 V). Resistors R7 and R8 limit the opto……
