Re: Sharp Aquos LC52SE94U hit by surge
If the current sense resistance is different, then it would alter the output power available.
Exceeding the limit would cause the circuit to fold back (I expect) leading to a sag in PFC bus voltage, which would eventually cause a sag in the output voltage of the power supply and/or other faults.
It could also just cut out if a pre-set limit occurs, or skip pulses (probably more likely.)
I seem to recall having a LCD TV with a PFC fault. The controller IC would become jumpy below about ~215V AC mains, the unit being rated for 100-265VAC. This was a rare event but would mean occasionally the TV backlight would flicker especially if things like a fridge had just started causing the mains voltage to dip.
I think I found a spare PSU for that one and didn't fix the old one, but if I were to take a guess, I'd say there was a chance the controller was erroneously detecting an over-current an automatically folding back.
Of course, the resistors could be the same. So you could draw more power. However, you'd start coming across other limits: the inductor might start saturating, which can cause excessive power dissipation in the MOSFET, damaging it. Or, the MOSFET could simply naturally run hotter, due to the higher load, leading to early failure.
If the current sense resistance is different, then it would alter the output power available.
Exceeding the limit would cause the circuit to fold back (I expect) leading to a sag in PFC bus voltage, which would eventually cause a sag in the output voltage of the power supply and/or other faults.
It could also just cut out if a pre-set limit occurs, or skip pulses (probably more likely.)
I seem to recall having a LCD TV with a PFC fault. The controller IC would become jumpy below about ~215V AC mains, the unit being rated for 100-265VAC. This was a rare event but would mean occasionally the TV backlight would flicker especially if things like a fridge had just started causing the mains voltage to dip.
I think I found a spare PSU for that one and didn't fix the old one, but if I were to take a guess, I'd say there was a chance the controller was erroneously detecting an over-current an automatically folding back.
Of course, the resistors could be the same. So you could draw more power. However, you'd start coming across other limits: the inductor might start saturating, which can cause excessive power dissipation in the MOSFET, damaging it. Or, the MOSFET could simply naturally run hotter, due to the higher load, leading to early failure.
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