# High side MOSFET Driver component selection

I'd like to drive high side and low side MOSFET for buck converter, so I have used IR2184s,(the image bellow) to do the job,

The frequency of oscillation is 1Mhz, so DRVR is a square wave signal of 1MHz frequency and 5V peak. VBATT=23V and the other components are shown in the image, The duty cycle is 50% and the mosfet used to be driven id IRF540

My circuit doesn't work as expected, (ie: I do not get a squar wave at bothe HO and LO)

I have recalculated the value of C6 but this doesn't solve the problem, and I don't know why ??

• show a sketch of the actual waveform. is duty cycle not 50%? are rise and fall times not ZERO_time? Do actual waveforms (from scope photos) have ringing? – analogsystemsrf Apr 13 at 10:52
• I would use more than 100nF at Vcc of U1. Keep C33 (as close as possible to U1) and add 1uF closest to U1. Since you power it with a battery, it is likely there are long leads between the battery and U1 and other components fed by the battery. So, you might need more caps on other places. – Huisman Apr 13 at 11:17

The turn-on propagation delay is typically 680 ns and worst case 900ns. When driving at 1 MHz 50% duty-cycle,$$\ t_{on}\$$ = 500 ns. So, you already turn off the gate driver, before it could drive LO or HO high.