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I saw a different H-bridge circuit than the H-bridge circuits I’ve seen before. What could the connection to the MCU in the lower left of the circuit be for?

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JYelton
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harmonica
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The resistor on the right is a "shunt" resistor. This is a small value resistor which is used to measure the current flowing into the motor down to ground (U = Rshunt*I). The same voltage is developped across the RC circuit. This circuit is a low-pass filter. This will ensure that only the average DC current will be measured by the MCU. The "MCU" output from the RC filter must be connected to the MCU's ADC for measurement.

Arthur Chassande
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    ... also please note that this RC smoothing is not used that much. The voltage across the shunt resistor is normally very small (a few mV, for thermal dissipation reasons) and needs amplification. A differential shunt current sense amplifier is a better way ... but comes at a higher price of course. – Arthur Chassande Jun 29 '22 at 11:15
  • So if I'm not misunderstood, the purpose of using the ADC pin is to detect overstrain of the motor and prevent it from breaking down. – harmonica Jun 29 '22 at 11:53
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    for instance yes, or any other kind of control loop system :) – Arthur Chassande Jun 29 '22 at 15:29