An operating circuit includes an amplifier having a first input terminal coupled to a reference voltage; a first transconducting element for selectively generating a first current; a second transconducting element for selectively generating a second current; a resistive element having a first terminal coupled to the first transconducting element; a capacitive element having a first terminal selectively coupled to the second transconducting element; and a switching device. The switching device has a first configuration to connect the first terminal of the capacitive element to the second transconducting element and connect the first terminal of the resistive element to a second input terminal of the amplifier, and has a second configuration to disconnect the first terminal of the capacitive element from the second transconducting element and connect the second input terminal of the amplifier to the first terminal of the capacitive element instead of the first terminal of the resistive element.
展开▼