A current detection circuit, comprising:
- a current transformer, including a primary-side circuit and a secondary-side circuit;
- a current sensing circuit, connected to an output terminal of the secondary-side circuit, the current sensing circuit including
- a rectification circuit, configured to convert an AC current output by the secondary-side circuit via the output terminal to a pulsed DC current,
- a power source conversion circuit including an energy storage element, the power source conversion circuit connected to the rectification circuit and configured to store energy for the energy storage element based on the pulsed DC current during operation in a charging mode, and the power source conversion circuit configured to generate a power supply current based on a voltage of the energy storage element,
- a mode switching circuit, connected to the rectification circuit, the mode switching circuit configured to be bypassed by the power source conversion circuit during operation in the charging mode, and configured to bypass the power source conversion circuit during operation in an energy release mode, and
- a current sensor circuit, separately connected to the rectification circuit, the power source conversion circuit and the mode switching circuit, the current sensor circuit configured to detect a pulsed DC current flowing back from the power source conversion circuit or a pulsed DC current flowing back from the mode switching circuit,
- a control circuit, configured to
- acquire electrical energy from the power supply current,
- determine that operation is in the charging mode or the energy release mode based on the voltage of the energy storage element, and
- acquire a detection value provided by the current sensor circuit;
- and
- a signal conditioning circuit, arranged between the current sensor circuit and the control circuit, the signal conditioning circuit configured to acquire electrical energy from the power supply current and configured to condition the detection value provided by the current sensor circuit;
- wherein the control circuit is further configured to
- determine that operation is in the energy release mode upon the voltage of the energy storage element being greater than or equal to a first value, and
- determine that operation is in the charging mode upon the voltage of the energy storage element being less than or equal to a second value, the first value being greater than the second value.