電能---->熱能
摸摸哪些器件發(fā)熱就知道了.

我說的是在NO LOAD的情況下,很難有較熱的元件.

待機(jī)損耗主要來源于
1)FET等開關(guān)損耗
2)變壓器損耗
3)RCD損耗
4)啟動(dòng)電路損耗
5)預(yù)負(fù)荷損耗(包括IC等)
主要解決方式:
1)降頻
2)降反壓
3)間歇式工作
4)用專用IC
按以上方式,即便用普通IC(像UC3842等),200W以內(nèi)的電源,待機(jī)損耗可以降到1W以下.

疑問:3842光啟動(dòng)電阻就耗電不少,如何做到1瓦以下?

各位仁兄,有做十幾瓦開關(guān)電源嗎?介紹一款給你,肯定超值!有興趣和我聯(lián)系.

CoolSET™ F2  
  Second Generation Integrated Power ICs with Enhanced Protection Features and Low Standby    

Features:  
Lowest standby power consumption <300mW @ no load condition
Lowest on-resistance for record efficiency levels
650V or 800V avalanche rugged CoolMOS Power MOSFET is integrated optionally
100kHz or 67kHz fixed switching frequency
Overload
Open loop
Overvoltage
Soft start
Thermal shut down
All integrated protection features are with automatic re-start
Improved modulated gate drive for lower EMI
Input voltages AC 85V...270V