Power supply circuit for selectively connecting a detecting module to a selected loop circuit to determine a current of the selected loop circuit

A power supply circuit comprising:

• a voltage converting module comprising at least one output port each for being connected to a load circuit to form a loop circuit;
• an input module to generate different selecting signals for selecting one of the formed loop circuits in response to user input;
• a detecting module capable of being selectively connected to the selected loop circuit, the detecting module comprising:
• a resistor with a resistance value far less than a resistance value of each load circuit;
• and
• a voltmeter connected in parallel to measure a voltage value of the resistor;
• at least one switch each comprising two ports connected between an output port and a corresponding load circuit;
• a selecting module connected between the detecting module and the at least one switch, comprising a first pair of ports and a plurality of second pairs of ports, each second pair of ports correspond to one switch and are connected to the two ports of the corresponding switch, the detecting module connected between the first pair of ports;
• and
• a processor to control the selecting module to connect the first pair of ports to one second pair of ports, and turn off or turn on each of the at least one switch to open or close one corresponding loop circuit, thereby connecting the detecting module to the selected loop circuit according to a received selecting signal;
• and further to determine a current flowing to the resistor according to the voltage value measured by the voltmeter and the resistance value of the resistor preset in the processor, and determine the calculated current as the current of the loop circuit.