Pulse frequency operation of regulated charge pumps

摘要

A regulating system (10) for a charge pump (12) employing a detection sub-circuit (28) and an enable sub-circuit (30) to operate an oscillator (26) and a channel-switching sub-circuit (32) in an automatic manner producing many of the advantages of previously unreconcilable skip mode and constant frequency mode type regulation. The detection sub-circuit (28) compares a feedback signal (52) from the output terminal (18) of the charge pump (12) to a reference signal (56) and produces an error signal (42) representative of output voltage deviation. Concurrently, the enable sub-circuit (30) compares a threshold signal (72) set for a minimum energy quanta which it is efficient for the flying capacitor (24) of the charge pump (12) to transfer to the error signal (42) and produces an enable signal (38) to enable the oscillator (26). An oscillator signal (40) then controls switching within the channel-switching sub-circuit (32) to set when the energy quanta are transferred and the error signal (42) further is used to control resistance in the charge path to the flying capacitor (24) to set the magnitude of the quanta.