Patent ID: 7071630

Claim:
An apparatus for closed-loop control of an output current (I OUT ) that is delivered to a load circuit from an inductor, the apparatus comprising: a transistor switching circuit that is arranged to selectively couple a switch node to a power supply when activated, such that the inductor is charged by an input voltage (V IN ) when the transistor switching circuit is activated, wherein the inductor is arranged to deliver the output current (I OUT ) to the load circuit when the transistor switching circuit is deactivated; a sense circuit that is arranged to provide a sense signal (V SNS ) in response to the output current (I OUT ); an error amplifier circuit that is arranged to provide an error signal (V ERR ) in response to a comparison between the sense signal (V SNS ) and a reference signal (V REF ); a ramp generator circuit that is arranged to provide a ramp signal (V RAMP ), wherein the ramp signal (V RAMP ) is reset to a predetermined level in response to a reset signal (ENR), and wherein a magnitude associated with the ramp signal (V RAMP ) is determined by an error signal (V ERR ); a comparator circuit that is arranged to compare the ramp signal (V RAMP ) to the error signal (V ERR ) to provide a comparison signal (V COMP ), wherein the comparison signal (V COMP ) is asserted when the ramp signal (V RAMP ) exceeds the reference signal (V ERR ); a feed-forward circuit that is arranged to activate a pulse signal (V FF ) when a voltage (V SW ) associated with the switch node decreases by a predetermined amount; and a latch circuit that is arranged to: assert the reset signal (ENR) when the pulse signal (V FF ) is asserted, activate the transistor switching circuit when the reset signal (ENR) and the comparison signal (V COMP ) are de-asserted, and deactivate the transistor switching circuit when the comparison signal (V COMP ) is asserted.