Current feedback in H-bridge

[Matinking]

Hi everybody!

I am going to sample the current of the dc motor embedded into the H-bridge circuit. I know that one approach is utilization of the below circuit, which is consists of an op-amp in addition to the sense resistor. But I have some obscurities for usage of aforementioned circuit...
Considering attached image, there are 3 terminals which should be determined for the non-inverting amplifier configuration... Vref, Rsense, and Vout
Would you please guiding me to connect this terminals in the H-bridge circuit, correctly???

Thank you

 

[barry]

I'm not sure what the point of the Vref signal is, it just provides an offset to your output voltage; you could just as well make Vref=ground. So, Rref is simply the box labeled "low side current sense", you connect the resistor between the bottom of the H-bridge and ground, and Vin is connected to the top of the resistor.

 

[Matinking]

Dear barry

thank you very much due to your clear illustration.... I'm just gonna need your confirmation for my guess about the Vout terminal : That should be connected to the input pwm pins of the system in order to complete the closed loop. Am I right???

 

[barry]

I'm not sure what you mean by "the input pwm pins". The Vout signal is a voltage proportional to current, and, yes, you can use this as a feedback signal, but you need some kind of 'controller' that accepts this feedback signal, compares it to a setpoint, and generates the appropriate PWM signal.