Patent ID: 9052846
Filing Date: 2015-06-09
Classification: G05F,H02M

Abstract:
1. A method of regulating an input supply voltage to a charge pump output voltage, comprising the steps of: receiving the input supply voltage; determining whether to use an auxiliary charge pump to start up and drive a primary charge pump according to a level of the input supply voltage, wherein the primary charge pump generates the charge pump output voltage; enabling the auxiliary charge pump to provide an intermediate voltage when the input supply voltage is lower than a reference voltage, the intermediate voltage having a higher level than that of the input supply voltage; and coupling the intermediate voltage to boost up the primary charge pump that drives a load, wherein the auxiliary charge pump comprises a voltage-dependent oscillator that is driven by the intermediate voltage and provides a voltage-dependent clock, the voltage-dependent clock having a frequency increasing with the magnitude of the intermediate voltage when the intermediate voltage is lower than a threshold voltage and saturating when the intermediate voltage reaches the threshold voltage.