Power Integrations公司的LNK603-606/613-616 LinkSwitch-II系列是高效的开关控制器,它集成了700V的功率MOSFET,新颖的ON/OFF控制状态机,用于自偏压的高压开关电流源, 频率抖动(frequency jittering),逐个周期的电流限制和带滞后的热关断电路,从而大大地简化了恒压/恒流转换器的设计.本文介绍了LNK603-606/613-616 LinkSwitch-II系列的主要特性, 功能方框图, LinkSwitch-II反激电源以及2.75W USB充电器的参考设计和电路图.

The LinkSwitch-II dramatically simplifies low power CV/CC charger designs by eliminating an optocoupler and secondary control circuitry. The device introduces a revolutionary control technique to provide very tight output voltage and current regulation, compensating for transformer and internal parameter tolerances along with input voltage variations.
The device incorporates a 700 V power MOSFET, a novel On/Off control state machine, a high voltage switched current source for self biasing, frequency jittering, cycle-by-cycle current limit and hysteretic thermal shutdown circuitry onto a monolithic IC.
Product Highlights
Dramatically Simplifies CV/CC Converters
Eliminates Optocoupler and all secondary CV/CC control circuitry
Eliminates all control loop compensation circuitry
Advanced Performance Features
Compensates for transformer inductance tolerances
Compensates for input line voltage variations
Compensates for cable voltage drop (LNK61X series)
Compensates for external component temperature variations
Very tight IC parameter tolerances using proprietary trimming technology
Frequency jittering greatly reduces EMI filter cost
Even tighter output tolerances achievable with external resistor selection/trimming
Advanced Protection/Safety Features
Auto-restart protection reduces power delivered by >95% for output short circuit and control loop faults (open and shorted components)
Hysteretic thermal shutdown – automatic recovery reduces power supply returns from the field
Meets HV creepage requirements between Drain and all other pins both on the PCB and at the package
EcoSmart  – Energy Efficient
Easily meets all global energy efficiency regulations
No-load consumption <200 mW at 230 VAC and down to below 30 mW with optional external bias
On/Off control provides constant efficiency down to very light loads – ideal for CEC and ENERGY STAR 2.0 regulations
No current sense resistors – maximizes efficiency
Green Package
Halogen free and RoHS compliant package
Applications
Chargers for cell/cordless phones, PDAs, MP3/portable audio devices, adapters, LED drivers, etc.



图1. LinkSwitch-II系列功能方框图



图2.节能的USB充电器电源(平均效率74%,无负载时的功耗小于40mW)




图3.没有偏置电源的LinkSwitch-II反激电源

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