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TPS2490 as a high-side MOSFET driver

Other Parts Discussed in Thread: TPS2490

Hi, 

I need to switch a resistor at a motor terminals to slow the motor rotation. This resistor has a low-side switch (with PWM command) and a high-side switch with an ON-OFF behaviour. As the HS command can be continuous, I would like to use the TPS2490 as a high-side mosfet driver, taking advantage of its integrated charge pump. But my problem is that the voltage can be as low as 3V, and the TPS2490 won't work with such a low voltage. 

My question is : is it possible to disconnect the VCC and Sense pin from the mosfet Vdrain and supply the controller with an unisolated auxiliairy power supply.

Thank you for your help,

Regards

  • Since the charge pump operates from VCC, it wouldn't be able to get much above 10V+14V or ~24V. Would it be possible to diode "OR" the 10V and 0-70V supplies together for a ~10-70V feed for VCC? That would allow the switch function to work but the FET won't be protected by TPS2490. For this case, the TIMER pin can be connected to GND thus disabling the fault timer (although shorting SENSE to VCC will over-ride fault sensing).