sampling

tangwei8802429

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I want to sample the output power of a switching power supply and use the ADC pin of a microcontroller for detection. For example, my switching power supply is 24V. Could you recommend some simple circuits?

maychang

If the output of the switching power supply is DC, sample the output voltage and output current of the switching power supply separately and then multiply them.

The output voltage of the switching power supply is relatively high, and can be divided by resistors and then sent to the microcontroller.

tangwei8802429

maychang posted on 2019-7-21 16:01 If the output of the switching power supply is DC, sample the output voltage and output current of the switching power supply separately, and then multiply them. Switching power supply output voltage comparison...

The voltage is constant, so is it enough to just sample the current? I just don't know how to sample the current.

maychang

tangwei8802429 posted on 2019-7-21 16:10 The voltage is always constant, is it enough to sample the current? I just don't know how to sample the current

The traditional method of sampling current is to connect a small resistor in series (shunt). However, the series resistor will reduce the voltage across the load a little (the voltage drop of the shunt).

If cost permits, consider using Hall current transformers.

maychang

tangwei8802429 posted on 2019-7-21 16:10 The voltage is always constant, is it enough to sample the current? I just don't know how to sample the current

The typical shunt voltage drop is 75mV, so it must be amplified before being sent to the microcontroller AD. Obviously, the frequency response of this amplifier must reach DC.

tangwei8802429

maychang posted on 2019-7-21 17:07 The traditional method of sampling current is to connect a small resistor in series (shunt). However, the series resistor will reduce the voltage across the load a little (the voltage drop of the shunt). If...

OK, thanks for the accuracy. I will try it out.

伟林电源

Just do an output current check and multiply it by your voltage feedback.