Hello,
I designed a STO circuit for a BLDC motor driver. I took reference from your TIDA design and I used TPS27S100APWPT IC. But it doesn't work effectively. I connect 24V to IN pins. When I connect 3.3V to EN and DiagEN pins I see 2V on the outputs instead of 24V. So I tried it again after dismounted the IC from driver, but I got the same results. Can you describe me what I'm doing wrong or the things that I need to be carefull before testing the IC?
Thank you.
Actually, I measured the voltage using a multimeter. I measured 24V on the IN pins (the power input pins of the TPS27S100A). However, on the output pins, I observe 0V in both cases, whether the EN pin is high or low. I also tried testing the IC alone by soldering wires to its pins, and I measured 2V when the EN pin is high.
The output pins of the TPS27S100A are connected to the supply pins of the DRV3205. I also cannot see 24V on the supply pins.
Hello,
I would recommend using an oscilloscope to observe EN, IN, OUT, and FLT.
It is possible either the EN signal is between its VIL and VIH thresholds shown below or thermal shutdown is being triggered. In between VIL and VIH, we cannot confirm if the device is ON or OFF, meaning the device could also be partially ON.
Additionally, we recommend if ILIM is not used, to pull ILIM pin to ground. Floating ILIM could cause a thermal shutdown event where the device will disable even when EN>VIH due to the temperature exceeding TSD.
Once you have collected the waveforms, we'll be able to see whether EN is between VIL and VIH or if thermal shutdown is being triggered by observing the voltages on EN and FLT when IN is 24V and OUT is 0-2V.
Best Regards,
Elizabeth
