Electronic – MOSFET half bridge driver not working


I have an IR2104 MOSFET half-bridge driver connected exactly as shown in an example circuit in its datasheet:
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I'm using two IRGPS4067DPBF IGBTs and a 100nF bootstrap capacitor.
The whole circuit including the high-side IGBT collector are running on 5VDC.
SD and IN are pulled to Vcc.
Yet for some reason both the high-side and low-side outputs of the driver are pulled to ground at all occasions (measured with an oscilloscope) and neither of them ever goes high no matter if IN is high or low.

I tried using a different driver yesterday (L6384) with exactly the same results, so I thought that maybe it's broken and bought a different driver today, but without any success as I explained.

What am I doing wrong?

Best Answer

IN pin should not be pulled high continuously , this driver is a bootstrap driver , which means it needs to recharge the bootstrap capacitor through the low side mosfet when the high side mosfet is off.

buttom line , IN pin should be PWM from 0 to around 95% but never to 100%.

if you want 100% , ( for some applications you do ) there is solutions like adding a charge pump ... etc

check out this app note from Texas instruments Providing Continuous Gate Drive Using a Charge


After checking the datasheet it seems you have another mistake , that is powering the IR2104 from 5v , the IR2104 accepts 3.3v and 5v and 12v logic inputs at IN and SD , but its supply (aka VCC ) should be above between 10v to 20v. the IGBT voltage can be 5v no problem .