Bridge Driver

Mar 10, 2011 1 Replies

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john1987 15 years ago

Hi, I am working with HIP chip HIP4081A. I am using the +12 volts power supply. I am trying to drive an inductive load. The thing is that after sometimes the transistors (MOSFETS) get really hot. I checked the microprocessor who is driving the chip seems generating correct timing waveforms for the HIP chip. But the noise coming back from the inductive load is destroying the HIP chip itself. I need some adivce on this urgently, When I lower the power supply to +10 volts than the chip works fine and does not get burned out. But I do need to operate the transistors at +12 volts.

The links to view the schematic are as follows

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Thanks John

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Jon Elson 15 years ago

Hmmm, hard to know. I used the HIP4080 some years ago, and had a lot of problems with it. While rated at 80 V, the field engineer admitted no one had ever gotten it to work above 59 V for the MOSFET supply.

Normally, the MOSFETs run on a higher voltage than the chip's VCC, but that shouldn't actually matter that much.

Yes, when the high-side transistors turn off, the inductive load wants to keep sinking current, and it has to come from the low-side transistors. The body diodes in those transistors are usually horrible, and take microseconds to turn on. This allows the floating high-side transistor's source to go below ground, and that forward biases things in the driver chip that should never be forward-biased. An ultra-fast rectifier across the low-side transistors will solve this problem, I use the ES3D for that purpose.

Jon

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