Patent ID: 8400129

Claim:
An adaptive constant on-time switching regulator, comprising: an input terminal operable to receive an input signal; an output terminal operable to provide an output signal; a switching circuit coupled to the input terminal; an output circuit coupled between the switching circuit and the output terminal, wherein the output circuit comprises: an inductor coupled between the switching circuit and the output terminal; an output capacitor coupled between the output terminal and ground; and a control circuit, coupled to the switching circuit, operable to control switches in the switching circuit to be turned on for an adaptive constant time, and be turned off for a minimum time, wherein the control circuit comprises: an adaptive constant on-time control circuit, operable to receive a logical signal and a current sense signal representing the inductor current on the rising period part of the inductor current, the control circuit providing an adaptive constant on-time signal; a feedback circuit, coupled to the output terminal, operable to receive the output signal and provide a feedback signal; a minimum off-time control circuit, operable to receive the logical signal and provide a minimum off-time signal; a logic circuit, coupled to the adaptive constant on-time control circuit, for receiving the adaptive constant on-time signal, the logic circuit coupled to the feedback circuit, for receiving the feedback signal, the logic circuit coupled to the minimum off-time control circuit, for receiving the minimum off-time signal, the logic circuit operable to provide the logical signal; a reverse current compare circuit, operable to receive a signal representing the inductor current on the falling period part of the inductor current, and provide a reverse current indicating signal; and a driver, coupled to the logic circuit, for receiving the logical signal; the driver coupled to the reverse current compare circuit, for receiving the reverse current indicating signal; the driver operable to provide a driving signal to the switching circuit to control the switches in the switching circuit to be turned on for an adaptive constant on time, and be turned off for a minimum off time.