Charge pump feedback control device and method using the same

Abstract

Charge pump feedback control device and method are provided. The device is coupled to the charge pump unit which receives an input voltage so as to generate an output voltage and has switches and at least one capacitor, the device includes: a compensation unit, a modulation unit, and a phase control unit. The compensation unit receives the output voltage, compensates the output voltage for stability, and generates an error signal. The modulation unit receives the error signal, modulates the error signal, and correspondingly generates a modulation signal. The phase control unit receives the modulation signal so as to generate phase signal, and controls the plurality of switches of the charge pump unit according to the plurality of phase signal so as to generate the output voltage through the input voltage charging/discharging at least one capacitor of the charge pump unit.

What is claimed is: 
     
         1 . A charge pump feedback control device, coupled to a charge pump unit which receives an input voltage so as to generate an output voltage and has a plurality of switches and at least one capacitor, the device comprising:
 a comparator, coupled to the charge pump unit, wherein an output end of the comparator is coupled to at least one capacitor and generates a comparative signal after comparing the output voltage and a reference voltage; and   a modulation unit, coupled to the comparator, receiving the error signal, modulating the error signal, and correspondingly generating a modulation signal of pulse skipping modulation; and   a phase control unit, coupled to the modulation unit, receiving the modulation signal so as to generate a plurality of phase signal, controlling the plurality of switches of the charge pump unit according to the plurality of phase signal so as to generate the output voltage through the input voltage charging/discharging the at least one capacitor of the charge pump unit.   
     
     
         2 . The charge pump feedback control device according to  claim 1 , further comprising:
 a voltage divider, coupled between the charge pump unit and the comparator, receiving the output voltage generated from the charge pump unit, and dividing the output voltage for the comparator.   
     
     
         3 . The charge pump feedback control device according to  claim 1 , wherein the modulation unit is a voltage controlled oscillator (VCO), coupled to the compensation unit for receiving the error signal, and generates the modulation signal using pulse frequency modulation according to the error signal. 
     
     
         4 . The charge pump feedback control device according to  claim 3 , wherein the compensation unit comprises:
 an oscillator, used for generating an oscillation frequency; and   a switch, coupled to the comparator and the oscillator, wherein the oscillation signal being pass when the comparative signal is at a high voltage level, and the oscillation signal being cut off when the comparative signal is at low voltage level so as to generate the modulation signal of pulse skipping modulation.   
     
     
         5 . A method for feedback control of charge pump, comprising:
 controlling an input voltage to charge/discharge at least one capacitor for generating an output voltage according to a plurality of phase signal;   comparing a voltage level of the output voltage to generate an comparative signal;   generating a modulation signal by skipping the output voltage according to the comparative signal; and   generating the plurality of phase signal according to the modulation signal.   
     
     
         6 . The method for feedback control of charge pump according to  claim 5 , further comprising:
 dividing the output voltage.   
     
     
         7 . The method for feedback control of charge pump according to  claim 6 , wherein the modulation signal is a pulse skipping modulation signal. 
     
     
         8 . The method for feedback control of charge pump according to  claim 7 , wherein the pulse skipping modulation is performed by a switch controlled by a voltage level of the comparative signal, the modulation signal being pass when the comparative signal is at a high voltage level, and the modulation signal being cut off when the comparative signal is at low voltage level.