IR2153 HO doesn't switch


diysmps Senior Member
did you try with another transformer if available bogdan? you can try change mosfet first let see if its working good.


New member
Fixed schematic is below. I powered the chip separately with a 12V supply and increased the input voltage. The rest of the circuit is just a bulb instead of the transformer and the input circuit without the bootstrap resistor.
First waveform is the high side mosfet without the input voltage. As soon as I increase that voltage (even a tiny bit), the waveform becomes the one in the second picture.
I will try one more thing, I have a board with SG3525 and IR2110, and I'll put it in place and see how it's performing.

Well, I have to admit that your information is not very detailed and often rather unclear.
1. What do the photos actually show? The GS-voltage, the HO-VS Voltage or what else?
2. What do you mean by "... mosfet without the input voltage"? Without an input voltage the MOSFET will not switch at all. :-/
3: Which voltage do you increase? What does tiny in that context mean? No voltage (0V) plus some mV is always a rather huge change!

It would be good if you measure some voltages on the high-side:
1. HO.
2. The Gate voltage of the MOSFET.
3. VB
all with respect to VS.
Your scope has 4 channels, so this should be no problem.
Choose the timebase that one or maximum two pulses can be seen.
Take a photo with a higher resolution! :)

You should swap one or some of these parts: the IR2153, the high-side MOSFET, the high-side buffer cap C3.
They probably got damaged during your tests with the wrong diode (1N5819) and with the wrong wired resistor (HO-GND).