I've also looked at using the UC2845 (usually a current mode flyback PWM driver) driving any old mosfet. If you average the PWM signal (while it's running closed loop) as an analog voltage , you can determine whether it is open or short circuit.
This is a great idea. You shoul;d submit it to EDN's Design Ideas- make yourself a few bucks.
Have you seen the DRV101
Thnaks for the pointer. I recently saw a TI part, but was only rated to 20V, for automotive applications. This one I can use!
Unfortunate that the only units with status indication, the ZXMS6002G and ZXMS6003G have a feeble 500mohm Rds , what kind of automative load only uses 1A? , heck a simple PTC placed in close proximity to the MOSFET tab would provide sufficient protection for a 12v / 1A load.
Have you seen the DRV101 , in a TO220 5pin package , meant for solenoid driver, hits it hard at first then throttles back to PWM, interestingly it has a fault output for both under and overcurrent.
I've also looked at using the UC2845 (usually a current mode flyback PWM driver) driving any old mosfet. If you average the PWM signal (while it's running closed loop) as an analog voltage , you can determine whether it is open or short circuit. But it won't go to 100% duty so only good for bulbs and coils / motors.
Underdriving the gate is a big MOSFET killer , so some kind of de-saturation detector would be helpful.
@Aubrey: Re:Do you know if there is a data sheet available? Perhaps it is still preliminary.
Yes, the datasheet is in Max's inbox - I asked him to forward it to you since I didn't have your email address readily available :-)
Correct, the part does not launch in production until Dec13/Jan14, so the datasheet is still a Target datasheet and the Final datasheet has not been released on the website yet. However, samples are available!
Hi Max, Thanks a lot for sharing the guide. This is a pretty elaborated description about the calibration methodology and the advantages of the newer devices with advanced current sensing technique, which make the calibration easier. I am also impressed to see the option for "no calibration", where the "typical" slope and offset correction factors could be used from the datasheet instead of adding a calibration process during production...this is good for the application where accuracy is not that important. Thanks!
This looks a very interesting device. I only seem to find a product brief. Do you know if there is a data sheet available? Perhaps it is still preliminary. I did find a YouTube video, but not much else. There is also supposed to be an evaluation kit, but I can't find stock of it or the part anywhere.
True, I agree with you on that it better be calibrated along with the ADC as a system. One could use the ADCsoften available built-in the modern microcontrollers. I will check out your & Max's blogs. Thanks for the information!