Charge pump feedback control device and method using the same
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.
1. A device coupled to a charge pump unit for feedback control, the charge pump unit comprising a plurality of switches and at least one capacitor, and also receiving an input voltage so as to generate an output voltage, the device comprising:
a compensation unit coupled to the charge pump unit, receiving the output voltage and generating an error signal accordingly, the compensation unit comprising:
an impedance; and
an amplifier, the amplifier comprising:
an output end;
a positive input end, coupled to a reference voltage; and
a negative input end, coupled to the charge pump unit and a modulation unit,
wherein the impedance couples across the negative end and the output end of the amplifier, and compensates the output voltage for stability to generate the error signal;
the modulation unit, coupled to the compensation unit, receiving and modulating the error signal, and correspondingly generating a modulation signal, wherein the modulation unit is a voltage controlled oscillator (VCO), coupled to the compensation unit for receiving the error signal, and generating the modulation signal using pulse frequency modulation according to the error signal; and
a phase control unit, coupled between an input end of the charge pump unit and an output end of the modulation unit, the phase control unit receiving the modulation signal, generating a plurality of phase signals to control the switches of the charge pump unit so that the input voltage charge/discharge at least one of the capacitors of the charge pump unit and generating the output voltage accordingly, the plurality of generated phase signals comprising at least three separate phase signals generated based on the received modulation signal.
2. The charge pump feedback control device according to claim 1 , further comprising:
a voltage divider, coupled between the charge pump unit and the compensation unit, receiving the output voltage generated from the charge pump unit, and dividing the output voltage for the compensation unit.
3. The charge pump feedback control device according to claim 1 , wherein the phase control unit is composed using a plurality of combinational logic, and used for synthesizing the modulation signal to the plurality of phase signals.
4. A method for feedback control of a charge pump unit, comprising:
controlling an input voltage to charge/discharge at least a capacitor for generating an output voltage according to a plurality of phase signals, the plurality of phase signals comprising at least three separate phase signals;
compensating the output voltage to generate an error signal, the compensating performed by a compensation unit coupled to the charge pump unit, wherein the compensation unit comprises:
an impedance; and
an amplifier, the amplifier comprising:
an output end;
a positive input end, coupled to a reference voltage; and
a negative input end, coupled to the charge pump unit and a modulation unit,
wherein the impedance couples across the negative end and the output end of the amplifier, and compensates the output voltage for stability to generate the error signal;
modulating the error signal to generate a modulation signal, the modulating performed by the modulation unit, wherein the modulation unit is a voltage controlled oscillator (VCO), coupled to the compensation unit for receiving the error signal, and generating the modulation signal using pulse frequency modulation according to the error signal; and
generating the plurality of phase signals according to the modulation signal.
5. The method for feedback control of charge pump according to claim 4 , further comprises:
dividing the output voltage.
6. The method for feedback control of charge pump according to claim 4 , wherein the modulation signal is a pulse frequency modulation signal.