Patent ID: 7847617

Claim:
A charge pump, comprising: a ring oscillator including odd number of inverters connected in series, wherein the outputs of the inverters provide a plurality of oscillating clocks; a pumping circuit including a plurality of pumping blocks coupled to each other for outputting a boosted voltage, wherein each pumping block is connected to a corresponding oscillating clock; and a feedback circuit for generating the power voltage of the oscillator in response to the boosted voltage, wherein the power voltage of the ring oscillator is adversely proportional to the boosted voltage, wherein the feedback circuit includes a charging path and a discharging path, the charging path is activated if the boosted voltage is lower than a reference voltage, and the discharging path is activated if the boosted voltage is higher than a reference voltage; wherein the charging path includes a first comparator, a first switch, a capacitor, and a current source, the discharging path includes a second comparator, a second switch, the capacitor and a current sink, the first comparator is coupled to the first switch to further control the charge to the capacitor, and the second comparator is coupled to the second switch to further control the discharge of the capacitor.