Patent ID: 9306454
Filing Date: 2016-04-05
CPC Classification: H02M,Y02B

Claim Text:
1. A control circuit in a boost switching regulator, the boost switching regulator being configured to receive an input voltage on a first terminal of an inductor and to generate a regulated output voltage on an output terminal for driving a load, the boost switching regulator comprising a main power switch coupled between a second terminal of the inductor and ground, a synchronous rectifier coupled between the second terminal of the inductor and the output terminal, and an output capacitor coupled to the output terminal and ground, the control circuit being configured to control the main power switch and the synchronous rectifier using a Pulse Frequency Modulation (PFM) feedback control loop, the regulated output voltage being fed back to the boost switching regulator as a feedback voltage on a feedback node of the feedback control loop, the control circuit comprising: a ripple injection circuit comprising a current injection signal generation circuit configured to generate a current injection signal and a feedforward capacitor coupled between the output terminal and the feedback node of the feedback control loop, the feedforward capacitor integrating a current associated with the current injection signal to generate a voltage ripple signal at the feedback node for use by the PFM feedback control loop, wherein the current injection signal is the difference between a first current indicative of a synchronous rectifier current flowing in the synchronous rectifier when the synchronous rectifier is turned on and a second current indicative of a load current flowing to the load.