![]() It is the lower collector capacitance of IGBTs that give them the faster dv/dt switching advantage at higher voltages when their higher saturation votage drop becomes less important. That doubles the gate capacitance, so it takes twice as long to transition, the switching losses are double and the maximum switching frequency is halved. P-channel MOSFETs cost twice that of N-channel because they need twice the area of silicon for the same conduction. Use the lowest frequency consistent with motor speed and torque control. That is especially important for high frequency PWM switching. The trick to using MOSFETs is to switch them quickly to avoid the VI losses during transition. Zero current or zero voltage drop makes for zero heating. That may be true below 24V, but above that, the gate drive of high side switches require level translation for both P and N channel devices. True but for a one off build the easier gate drive could compensate for the increased cost. This is one of the circuits I have been looking at and wondered if I changed the transistors for more powerful MOSFET ones I have ordered whether it will work the same or not for what I need. I just need a bit of a push and help on where to begin and why. ![]() I have been advised to look into using a H-Bridge driver chip as well but I don't know where this could be connected in a circuit I design or find. The input signals will come from a pwm speed controller. What I do know is that the transistors I need to use are MOSFETS (both npn and pnp) that need to be around 60V/70A. I have found multiple circuit designs online where some use diodes and capacitors and others don't. ![]() Since the motors that need to be driven are high powered (dc motors and do not know any specs but can find out) I am struggling to decide on a circuit design. I understand only the basics of a H-Bridge about how it works and what type of transistors I will need to make it work. I have no access to what this H-Bridge looked like or what transistors where used etc. ![]() As part of a group project I have been given the task of building a H-Bridge circuit to replace a previously built one in a fighting robot. ![]()
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