DRV8837C: How to detect stalling of valve?

Shaw Wong

Part Number: DRV8837C

Hi,

Our customers use DRV8837C to drive valve, and VM directly connects to battery about 3.7V. When the valve stalls, the stall current is about 300 mA. As a result, the voltage of battery is pulled down, then MCU resets because of low voltage. So, what usual methods to detect stalling of valve using DRV8837C? How to avoid large voltage drop when stall happens? Thanks!

over 8 years ago

0 Rick Duncan over 8 years ago

TI__Guru** 114905 points

Hi Shaw,

There are two methods:

1) Monitor the back emf -- the blog: e2e.ti.com/.../easy-cruise-control-for-brushed-motors-using-bemf is a guide for monitoring the BEMF

2) Monitor the current in the motor. This is more complex, and may require an amplifier.

In addition to this, separating the VM from VCC (mcu and DRV8837C VCC) by using a schottky would be beneficial. Placing a capacitor on the VCC side would allow the mcu to remain operational during the stall. Please see the blog: e2e.ti.com/.../divide-and-conquer-your-battery-powered-designs

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DRV8837C: How to detect stalling of valve?