Switching voltage-controlled current source

A method of compensating a parasitic capacitance in a switching voltage-controlled current source,

• the switching voltage-controlled current source comprising:
• a current source input terminal for receiving a first input logic signal and a current source output terminal for outputting current;
• a first logic circuit comprising a first logic input terminal connected to the current source input terminal, a first logic output terminal for outputting a current control signal, a first supply terminal for connecting to a power supply and a first ground terminal for connecting to the ground;
• a first resistor coupled between the first logic output terminal and the current source output terminal;
• a second resistor coupled between the power supply and first supply terminal and a third resistor coupled between the ground and the first ground terminal;
• wherein the first logic circuit is operable to selectively couple the second resistor or the third resistor to the first resistor;
• the method comprising:
• in response to switching of the first input logic signal from a first logic state to a second logic state, generating a first amount of electric charge by a first charge supply circuit to compensate a first charge difference in a parasitic capacitance formed at a current source internal node connected to the first logic output terminal and one end of the first resistor;
• and
• in response to switching of the first input logic signal from the second logic state to the first logic state, generating a second amount of electric charge by a second charge supply circuit to compensate a second charge difference in the parasitic capacitance formed at the current source internal node.