I designed this H bridge circuit. Will send the PCB for manufacturing soon, but just wanted to make sure I'm not doing a silly mistake. I want to drive the FETs at 15 kHz frequency. Given the current capabilities of IR2101, I guess it should be fine as Qg if the FETS are 34 nC.Schematic I need to drive the motors at 30 A max. TOP LAYER layout

Bottom layer layout

  • 1
    \$\begingroup\$ Where are the decoupling capacitors on the gate drivers? Do you have a snubber diode across the motor to account for any back-emf voltage spikes? \$\endgroup\$ – LukeHappyValley May 3 at 11:36
  • \$\begingroup\$ What's the input voltage? What does the layout look like? \$\endgroup\$ – winny May 3 at 12:13
  • 1
    \$\begingroup\$ I'd suggest putting a pull down resistor on the gate of each FET as well as a diode in anti-parallel across your gate drive resistors (may not be necessary at these low speeds, but helps with turn off times). Luke and winny also make good points. The most important part of this board will be the layout, you can get more help if you post that image as well. \$\endgroup\$ – Stiddily May 3 at 12:38
  • \$\begingroup\$ @LukeHappyValley doesn't the 100uf MLCC cap (C3 in the schematic) does the decoupling for the gate drivers. do i need 2 of those capacitors for 2 drivers? I cant add a snubber diode across the motor as i need to drive the motors in both directions. \$\endgroup\$ – Shivanshu Mahim May 3 at 12:42
  • \$\begingroup\$ @winny 24volts at bat++ aka vcc \$\endgroup\$ – Shivanshu Mahim May 3 at 12:44

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.