This high side linear PFET motor controller, with brake, works pretty well. However the LM358 does not fully shut off the main fets. Fet2 is the work around: It opens the output channel during brake mode to prevent shoot through.
I have tried a RR op amp (LMC 6482 IN) but it too does not return all the way to VCC at zero input.
I have tried a pull up resistor with the 358 and found the same off gate voltage (VCC minus about 1.3) The SUP90 PFETS have a -1 threshold.
(Maybe a pull up resistor would work with a RR op amp?)
MAIN QUESTION: Can I use an analog switch IC to allow the Feedback leg to select a reference voltage at shut off to send a RR op amp all the way up?
Is the DG419 an appropriate switch for this? (I cannot get it to simply switch like a relay. I don't understand the VL input)
I welcome all suggestions and comments on this circuit; and how best to achieve shut off so I can eliminate the series FET #2.
(those are hall effect switches on the left for the speed control)
I have tried a RR op amp (LMC 6482 IN) but it too does not return all the way to VCC at zero input.
I have tried a pull up resistor with the 358 and found the same off gate voltage (VCC minus about 1.3) The SUP90 PFETS have a -1 threshold.
(Maybe a pull up resistor would work with a RR op amp?)
MAIN QUESTION: Can I use an analog switch IC to allow the Feedback leg to select a reference voltage at shut off to send a RR op amp all the way up?
Is the DG419 an appropriate switch for this? (I cannot get it to simply switch like a relay. I don't understand the VL input)
I welcome all suggestions and comments on this circuit; and how best to achieve shut off so I can eliminate the series FET #2.
(those are hall effect switches on the left for the speed control)
Attachments
-
337.6 KB Views: 24