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Original question:

TPSI3050: Design with TPSI3050

TPSI3050: Design to drive depletion MOSFET

Javier Vara
Expert 1595 points
Part Number: TPSI3050

Tool/software:

I am trying to use TPSI3050 to drive a depletion MOSFET, instead of a standard enhancement MOSFET. I know this is probably not the intended usage of the chip but I thought it should work. To generate the negative voltage I have connected VDRV to the source of the MOSFET and VSS to the gate (opposite of what you would normally do). And the circuit is not working as I was expecting. Would you expect this configuration to work?

Another problem that I have is that I had ordered by mistake TPSI3050S instead of TPSI3050, so I am currently waiting for the other part to arrive which will take a few days. However, I tried pulsing the input "DRIVE" and was hoping to see some negative voltage pulses in the mosfet gates, but I don't see anything. VDDH is at 10.2V above VSSS as expected.

Any help?

  • 0
    Expert 1595 points

    I have just realised the pulse is very short, and together with the capacitance load and the relatively large resistor (100 Ohms) prevented the MOSFET from fully switching on/off, but I can see the gate pulsing. This should be sorted with the new device TPSI3050 that I am waiting for. So I think we can close the issue, I will reopen if the new device doesn't work.