QH7939 is a single-stage power factor correction, a source of high precision LED constant current control chip, the original edge feedback with dimming control function, apply to 85 vac - 265 vac full range of input voltage of the flyback type isolation or lifting pressed unfenced LED constant current power supply.Integration of active power factor correction circuit, can achieve high power factor and low total harmonic distortion.Because working in the inductance current critical continuous mode, the power MOS tube in zero current open state, the switch loss was reduced, at the same time, the utilization rate of transformer is higher. 
Using proprietary current sampling mechanism, the work to the original edge feedback mode, without secondary feedback circuit, high precision output constant current control can be realized, saving the cost of the system and volume, improve the reliability of the system. 
USES the patent of the line voltage and load compensation technology, can achieve excellent line voltage regulation and load regulation.Line voltage compensation coefficient can also be adjusted by external components. 
Built-in multiple protection function to enhance system reliability, including LED open-circuit protection, LED a short circuit protection, chip power over-voltage protection, under-voltage protection, open circuit protection and current sampling resistance week period flow, etc.All protection with automatic restart function.
In addition, the regulating function for overheating, decrease the output current when driving power supply overheating, in order to improve the reliability of the system.Can adjust temperature through external resistor set of overheating.
 
The characteristics of


Single stage, the active power factor correction, high PF value and low THD
The original edge feedback constant current control, without secondary feedback circuits
With dimming interface
Plus or minus 3% LED output current precision
Excellent line voltage regulation and load regulation
Inductor current critical continuous mode
Low starting current 28 (ua)
FB feedback resistance value is high, low power consumption
LED open/short circuit protection
Current sampling resistance open circuit protection
Current limit cycle primary side current
Chip power over-voltage/under-voltage protection
Automatic restart function
Overheating regulating function
Overheating temperature can be set in a external adjustment
The SOP - 8 encapsulation

 深圳弘友電子科技有限公司是一家專業(yè)從事計(jì)算機(jī)軟硬件、電子元器件、數(shù)碼產(chǎn)品及通訊產(chǎn)品的研發(fā)、生產(chǎn)及銷售為一體的技術(shù)方案商及產(chǎn)品經(jīng)銷商。公司一直專注于電路保護(hù)行業(yè)，奉行品牌化戰(zhàn)略方針，努力為客戶提供最優(yōu)質(zhì)的產(chǎn)品及最優(yōu)秀的服務(wù)；公司在LED照明方面也有杰出的表現(xiàn)，為客戶提供的系統(tǒng)解決方案在質(zhì)量上和價(jià)格上都有很好的優(yōu)勢(shì)；公司還授權(quán)代理力特、村田等知名品牌，并授權(quán)經(jīng)銷TI、ON、MPS及Avago等一線品牌，為客戶提供價(jià)格優(yōu)異的電源IC、保險(xiǎn)絲、二極管、電容及電阻等產(chǎn)品。