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I'm trying to use the coil with a PWM of motor drivers(DRV8837). But there are some problems.

I'm using stm32f1 MCU, IN1 : 80% 400hz, IN2 : 0% 400hz PWM

output of the coil is abnormal... When you see the picture, the signal of OUT 2 is not zero..

Normally, OUT1 is 80% PWM and OUT2 is near 0???

Why are IN 2 and OUT2 different?? enter image description here enter image description here

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  • \$\begingroup\$ read the data sheets carefully, both for the actual part, and the supplement that tells you how the braking works, and can be gimmicked to use both halves of the H bridge independently \$\endgroup\$ – Neil_UK Jul 28 '17 at 7:09
  • \$\begingroup\$ ... especially figure 2 \$\endgroup\$ – Neil_UK Jul 28 '17 at 7:15
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DRV8837 doesn't have a 1:1 relationship between INx and OUTx.

When both inputs are low, the outputs are high impedance. When both are high, both outputs are low, for motor braking. It's only when the inputs are different that both outputs are driven, and in the sense you'd expect.

See figure 2 from the datasheet.

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