VNH3SP30 Shorted

I get a MD01B with VNH3SP30. After using for a few minutes, the motor stop moving. I am using the power window motor which is located in car (automotive). The motor is being used to push and pull the car window automatically. After checking the driver, the OUTB is shorted to VCC. How can this happen since there are so many protection on the driver itself? Thanks


That does sound unusual. Can you provide some more information about the circumstances of the malfunction? What voltages and controls were you using, did smoke come out, were things working as expected before the failure, etc. Do you know how much current your motor draws?

Also the outputs have diodes to Vcc; are you sure you are not just measuring those when you say the output is shorted to Vcc?

- Jan

Jan, Thanks for fast response. Yup, this sound very unusual. I am testing my power window motor, without any load and the driver is connected to PIC MCU. Vcc was 12V, the other control pin that is connected to PIC is MOTA, MOTB and the PWM, ground is common. It works perfectly fine at the beginning, but it stop working after 2 minutes of forward, reverse and stop. No smoke come out. Expected current should be around 5 to 7 A, but I din measure it because I am sourcing the driver directly from SLA (Sealed Lead Acid) battery.

Yup, I confirmed is shorted because I tested both side of multi meter probe. I also thought it wast the internal diode at the beginning, but after changing the polarity of probe, it is being shorted.

Well, I’m almost out of ideas. My only thought is that perhaps if you switched directions quickly, the current could have gotten too high. If you contact support or otherwise let us know where to send a replacement, we can send you another one.

- Jan

Jan, Thanks. I don need the driver now, furthermore shipping will be very expensive because I am in Malaysia. Anyway my purpose is to understand the root cause, since the driver have comprehensive protection, it seem to be impossible for it to be damaged. How much current can it stand for back EMF during switching?


I don’t have any information beyond what is in the datasheet. If you’re switching directions a lot, your current can spike higher than the stall current, and the chip might not be able to detect it quickly enough to turn off the outputs before they get destroyed.

- Jan

Thanks. Is OK, I just want to understand the root cause. Anyway I don think the direction changing cause the driver to breakdown. It might be something else, will try to explore more.

Another question, what would be the maximum voltage that we can connect to Vcc?



According to the VNH3SP30 datasheet, the maximum operating voltage (Vcc) is 36 V, but the chip can survive voltage spikes on Vcc as high as 40 V. However, in our experience, shoot-through issues make it impractical to use the VNH3SP30 above 16 V.

- Ben

Previously I saw a short at output to Vcc. Now i am seeing another symptom. INA shorted to Vcc. Very weird right? The I use a PIC to control the INA and INB, also the PWM. I really don understand why can it short to Vcc. I try to investigate more. Desolder the VNH3SP30 chip from the baord using a oven. using multi meter to measure the board, no short on board. However the chip is short from pin 5 INA to Vcc pin. Could any one help me on this? I am driving a power window motor like previous I explained. Current can go up to 20A with full load.

That is very weird. I haven’t seen that sort of problem before, and I can’t think of how normal use would cause that.

- Jan

Has anyone found a solution for this problem. I have been trouble shooting the same issue for the past 3 days and just tracked the problem to exactly what your explaining. OutA is being shorted to ground and causing my PIC to brownout and lock up my system. I need to figure out why this is happening and how it can be fixed ASAP, any help would be appreciated.



We do not have an explanation of this problem. Are you using one of our carrier boards, or the chip by itself (e.g. on your own custom board)?

- Jan