I have never used an H-bridge before, but now I want to toy around. Reading this document the author uses IR2110 (Datasheet) with IRF840 (Datasheet IRF840), and these datasheets will be my starting point.

Questions for the driver:

  1. Datasheets mentions Io as 2A, and defines as "Output short circuit pulsed current". Is this the maximum value for when there is an error in the H-bridge, for example if I accidentally open Q1/Q2 (left side) at the same time? If not, what is it?

  2. Figure 26B (page 13) shows "Output source current vs. Voltage", and 3.5A typical at 2V. As a MOSFET-gate has a lot of resistance the current will not go into there, so where's this 3.5A of current going?

  3. "Feature: undervoltage lockout for both channels". What does that mean? (The datasheet is incredibly scarce regarding information)

  4. The datasheet does not mention any typical values, or anything, regarding the bootstrap capacitor and diode. How do I know what values I should use?

Questions for the MOSFETs:

  1. Id (drain current) is set to 8A according to the datasheet. If my load, after the H-bridge, is supposed to sink 1A current continuously, is parameter Id the one I should in particular keep my eye on? (I know there's a lot of variables involved, but I want to keep it simple just to get the hang of it)

  2. I'm having a struggle interpreting the charts. What I want to find out is how hot the MOSFETs will be in in the H-bridge, when supplying 9V / 1A to my load, so I know get a ballpark value for the heatsink. Which chart in the datasheet is the one I should look at?

General questions for driver + MOSFET:

  1. There's a lot of MOSFETs and a lot of different drivers. Basically, what parameters do I need to lookup in the datasheets to find if driver + transistors are "compatible" (so to speak) in my future H-bridge?

  2. Hypothetically, let's say my load would sink 15A current. Will these 15A come from the MOSFETs only, or will any of it come from the driver as well? Put in other words; if I in the future need to replace the MOSFETs to more tougher ones (more amps), do I also need to redesign the circuit and replace the driver as well?

  • \$\begingroup\$ Too broad, too many questions and not enough research into MOSFET gate-source characteristics. Start at a lower entry level such as a question just about MOSFETs. \$\endgroup\$ – Andy aka Feb 8 at 11:30
  • \$\begingroup\$ By the way, to avoid sacrificing numerous FETs and GateDrivers and MCUs on the altar of learning, always use a GROUND PLANE or a sheet of copper, within 1/16" of all your high-speed and/or high-current wires and traces. \$\endgroup\$ – analogsystemsrf Feb 8 at 13:26
  • \$\begingroup\$ Take a look at application note AN-978 infineon.com/dgdl/… \$\endgroup\$ – John Birckhead Feb 8 at 14:29

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