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I am currently implementing a Half-Bridge using an IRF520PBF (Link to Datasheet) for the lower part of the bridge and I am currently looking for a PMOSFET for the upper part of the bridge (I am aware that I could use the same NMOSFET for the upper part of the bridge as well if I use a high enough Gate-Voltage to switch the upper MOSFET on.)

I basically have the following questions, since this is my first H-Bridge:

(1) Do manufacturers usually provide a "complementary" PMOS for every NMOS they sell and would that PMOS have the same characteristics (e.g. on-state resistance, gate capacitance etc.)?

(2) Is it common in practice to use both NMOS and PMOS or do people prefer to only use one type (maybe for cost reasons or similar)?

(3) Is there anything specific I need to pay attention to in order not to accidentally short-circuit the supply voltage? My concern is that I might switch one MOSFET on faster than I switch the other one off effectively short-circuiting the supply voltage. I thought about using an "asymmetrical" gate resistor with Diode in order to avoid that (see also the Schematic below). However, this configuration has the problem of potentially interrupting the inductor current leading to large voltage spikes. I am using the following Gate-Driver: ([Link to Gate-Driver](https://octopart.com/lm5112sd-texas+instruments-24848588"Link to Gate-Driver")).

schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ 1. Usually only for some small signal transistors, not power devices. 2. Not really. Linear audio amplifiers might be the exception. 3. Dead-band, startup behavior, sudden load changes, cycle by cycle current limitation and any DC offset it would inflict, recirculating currents during breaking and so on. Are you dead set on PMOS? \$\endgroup\$ – winny Sep 16 '18 at 18:21
  • \$\begingroup\$ I'm not at all dead set on PMOS, it's just that I don't know what is "best practise". \$\endgroup\$ – Mantabit Sep 16 '18 at 18:32
  • \$\begingroup\$ NMOS all around and appropriate gate drive rail(s) \$\endgroup\$ – winny Sep 16 '18 at 18:39
  • \$\begingroup\$ Consider using something like ONSemi FDD8424: onsemi.com/pub/Collateral/FDD8424H-D.pdf This gives you both low and high side of the bridge element in a single device. \$\endgroup\$ – Jack Creasey Sep 16 '18 at 22:29

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