Other Parts Discussed in Thread: DRV8833, TIDA-00757, TPS62745
I have question regarding the DRV8837 from related question that I linked here. It is said that in order to detect stall condition it can be configured with a resistor and feed the sense voltage to the microcontroller ADC.
For the DRV8837, you can calculate how much current you will see in a stall condition and add a sense resistor between the GND pin of the device and GND. Then, by measuring the voltage across it with an ADC, you can find out if the stall current is reached. Note that doing this adds voltage offset to the ground of the device, so you must account for it in the rest of your pin voltages (e.g. nSLEEP).
It seems to me this method works to determine stall condition at instant. However my requirement needs to limit the current to the motor. My device is a smart lock uses 4 AA batteries and drive a mortise lock. For example when the motor hits something and the current goes up, I want the motor to be able to deliver up to a maximum constant torque with a certain current value (around 1.2 A) for up to 200 ms before I determine that my smart lock hits a stuck condition.
Because sometimes it can be the lock cylinder itself that is quite hard to be driven and I don't want the motor to draw current as much as it wants because when my device battery voltage already on low level like 5V, without current limit the battery drop voltage will be too big to make the whole system resets.
With that being said, DRV8837 satisfies my need for small package 2x2 mm, the pricing and minimum pin control.
- Are there any methods/suggestions to current limit this driver instead of just detect max current at instant?