Switching current source circuit and control method thereof

A control method for a switching current source circuit, wherein the switching current source circuit comprises a transistor pair formed by first and second mirror transistors, a switch coupled between gates of the first and second mirror transistors, the switch being controlled by a control signal, a first capacitor coupled to the gate of the second mirror transistor, and a second capacitor coupled between the gate of the second mirror transistor and a ground, comprising:

• draining a bias current from a power supply via the first mirror transistor;
• draining an output current corresponding to the bias current from the power supply via the second mirror transistor when the switch is turned on;
• and
• selectively providing a first voltage or a second voltage different from the first voltage to the first capacitor in response to a switching state of the switch, by a voltage generating unit receiving the control signal.

A control method for a switching current source circuit, wherein the switching current source circuit comprises a first mirror transistor coupled between a power supply and a current source, and a second mirror transistor coupled between the power supply and a loading device, comprising:

• draining a bias current from the power supply to the current source via the first mirror transistor;
• selectively connecting or disconnecting gates of the first and second mirror transistors utilizing a switch controlled by a control signal;
• coupling a first voltage provided by a voltage generating unit to the gate of the second mirror transistor when the gates of the first and second mirror transistors are connected;
• and
• coupling a second voltage provided by the voltage generating unit to the gate of the second mirror transistor when the gates of the first and second mirror transistors are disconnected, the second voltage being different from the first voltage,
• wherein when the gates of the first and second mirror transistors are connected, an output current corresponding to the bias current is drained from the power supply to the loading device via the second mirror transistor, and wherein the voltage generating unit receives the control signal and selectively provides one of the first voltage and the second voltage according to the control signal.