power supplyswitch-mode-power-supply
I know this might be a little bit funny question. But how can you determine the current that will used up as well as the power rating, when you a designing a power supply unit for a device. Because usually, I will always know the voltage, say 5V, but how can I calculate the current the device will use up.
Thanks.
A single-ended reading from the perspective of your micro is the way to go. Use an accurate analog circuit to compute the difference and quantize that difference with a single ADC channel to get your reading.
I suggest using a smaller shunt (something that will produce 10mV at your maximum load) and a part from the INA210 family - these parts are highly accurate and work in both the high-side and low-side.
If you don't end up with the exact gain you want, you can simply voltage-divide the output of the INA21x and feed that into your ADC input.
It appears to be a fixed voltage power supply. 12Volts at up to 2A. It has a potentiometer marked "Vo Adjust" which would be "output voltage adjust" which would be a useful thing on a constant voltage supply
It does not appear to be a constant current supply. A constant current supply would have a voltage range rating (say, for example, 5V-20V) and a current rating. This has a single voltage rating (12V) and a single current rating which is typical for fixed voltage supplies.
Best Answer
What current will be used is determined by the load, not the power supply. We've had a number of questions like this before, like "how do I limit the current of my 5A supply to 1A".
What your device will need is just the addition of the current for the different components on the board. You usually start with the power-hungry parts: motors, relays. For a microcontroller you'll have to look up in the datasheet what it needs at a given clock frequency.
If you have a lab supply which displays current you may use that as a rule-of-thumb, but you may want to give it some headroom. Used current is definitely useful if you want to design a power supply.