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I am trying to drive H bridge using the following configuration I am producing an inverting.

4 * N channel mosfets Fdd8447 gate driver ic TC4428 (used alternatively IX4428 and IXDF604 but no avail) Frequency stays <15Hz Power rating remains within half a watt At the Output I have 2.2K Ohm resistor 1Uf capacitor

I am not using IR2110 since I cannot produce the required +10V on high side gate as my max output amplitude stays within 20V. I am able to produce the required wave but I get wave this after applying the capacitor... otherwise worst...after adding the capacitor there is unusual sound in the gate driver as well...in fact I have even burnt one. Whats the problem? enter image description here

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Furthermore my load is not motor but a small and a capacitive one like the human skin

  • 1
    \$\begingroup\$ Is that a polarized capacitor at H bridge output? \$\endgroup\$
    – Long Pham
    Jan 2 '19 at 15:43
  • 3
    \$\begingroup\$ That looks like a low side FET driver with no bootstrapping circuit (?) If so, those top N-channel MOSFET'S can't be driven properly. \$\endgroup\$ Jan 2 '19 at 17:10
  • \$\begingroup\$ No I have used 1uf non polar capacitor the schematic is misleading \$\endgroup\$ Jan 3 '19 at 7:40
  • \$\begingroup\$ If I use high side driver as well how can i generate the additional volatge usually +10V when the output I want is ranged 5V to 20V wave \$\endgroup\$ Jan 3 '19 at 7:45
  • 2
    \$\begingroup\$ It's very unclear what you want. What is your supply voltage? Do you want a 5V to 20V square-wave across the load? That implies you want a voltage drop across your switch transistors in which case there is little reason to bother with MOSFETS. \$\endgroup\$ Jan 3 '19 at 11:05

At the Output I have 2.2K Ohm resistor 1Uf capacitor

Using a polarized capacitor here results in major problems, as the capacitor can break through if the voltage is applied negatively. In that situation the current through the capacitor is not limited and also the/both MOSFET break through too.

(Addiionally, please provide the same values in the schematics as in the text. 100 pF is usually not polarazed, but usually 1 µF).

Also the ratings of the capacitor are important. With an unlimited 1 µF at the outputs at the bridge, and C has a low ESR, the inrush current through the capacitor is very high!

  • \$\begingroup\$ I have used 1uf non polar smd capacitor. Any values given in schematic should not be followed \$\endgroup\$ Jan 3 '19 at 7:38

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