get2kamal
Junior Member level 1
hai every one
i am using this ckt for o/p over current protection in smps.
this ckt is working effectively at normal operating condition but when temp rises
(@ 50°c) it is gonig gracy.example ,,,..... if nominal load current is 3A ,,, i set over
current protection at 3.2A it is working fine at normal temp if temp rises around
50°c ambient , q8 (bc547)(β 200) due to temp drift starts conducting earlier so at
normal load current it self over current protection is accuring (fold back) and o/p
voltage starts decreasing, so i am planning to do temp compansation using
thermistor,,, i want the over current protection to be same @50°c,,,, so if any one
familiar with temp compansation using thermistor,,,, give me your suggestions,,i
am running out of time ,,,,, good suggestions will be appreciated.
kamal
[/url]
i am using this ckt for o/p over current protection in smps.
this ckt is working effectively at normal operating condition but when temp rises
(@ 50°c) it is gonig gracy.example ,,,..... if nominal load current is 3A ,,, i set over
current protection at 3.2A it is working fine at normal temp if temp rises around
50°c ambient , q8 (bc547)(β 200) due to temp drift starts conducting earlier so at
normal load current it self over current protection is accuring (fold back) and o/p
voltage starts decreasing, so i am planning to do temp compansation using
thermistor,,, i want the over current protection to be same @50°c,,,, so if any one
familiar with temp compansation using thermistor,,,, give me your suggestions,,i
am running out of time ,,,,, good suggestions will be appreciated.
kamal
[/url]