STCMB1 Second Level OCP Protection and Auxiliary Circuit

[MNafi]

Hi,

I am curious that how can ı choose electrolytic capacitor of auxiliary circuit? 

Firstly, I used 10uF electrolytic capacitor at Vcc pin.When I short circuit the output, the HB mosfets has failed.

Then I notice that STCMB1 datasheet mention this topic. According to STCMB1 datasheet, an electrolytic capacitor of at least 22 μF (typ. value) must be connected between the pin and GND. But when ı place 22uF electrolytic capacitor, I'm having trouble with the short circuit test. After a short circuit (about 20s), it causes the LEDs flickering.

Therefore, I used 100uF electrolytic capacitor at Vcc pin.I thought I solved the problem using 100uF but i encountered a new problem. I produced 10 driver and tested them. Almost half of them are undecided about working. The driver which worked yesterday, it does not work today.

 

 

[AndresGG]

Hi, how did it go with the power supply design?
I'm designing a power supply with the same chip, but I'm having some problems.

[AndresGG]

Hi, I have problems with voltage stability. When the load increases, the output voltage drops. To work with this high load, I modify the ISEN_HB elements. Then, when working with a lighter load, the transformer makes noise.

[AndresGG]

Hi, can you help me with some advice on sizing the HB current limits so that the OCP protection does not activate? I am sizing a 200W 36V power supply and I cannot get the power supply to work at more than 1A.