PWM controller and control method for a DC-DC voltage converter
AssigneeRichtek Technology Corporation
InventorsKo-Cheng Wang, Kuo-Ping Liu, Chih-Wei Tseng
Life of this patent
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Abstract
A PWM controller and control method for a DC-DC voltage converter filter the high-frequency component of the voltage at the phase node between high-side and low-side elements of the voltage converter to generate a signal synchronous and in phase or out-of-phase with the inductor current of the voltage converter, to achieve a low-ripple output voltage and stable loop control.
Claims22
A PWM controller for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM controller comprising:
- a synchronous-signal generator connected to the phase node, filtering out a high-frequency component of a phase-node voltage at the phase node to generate a first signal synchronous and out-of-phase with the inductor current;
- and
- a PWM comparator circuit connected to the synchronous-signal generator, generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the synchronous-signal generator comprises:
- a first low-pass filter connected to the phase node, generating a second signal synchronous and in phase with the inductor current;
- an error amplifier connected to the first low-pass filter and the PWM comparator circuit, receiving the second signal at a negative input terminal and a reference voltage at a positive input terminal to generate the first signal;
- and
- a second low-pass filter connected to the first low-pass filter and the error amplifier, filtering out an AC component of the second signal to generate the reference voltage.
A PWM controller for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched b a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM controller comprising:
- a synchronous-signal generator connected to the phase node, filtering out a high-frequency component of a phase-node voltage at the phase node to generate a first signal synchronous and out-of-phase with the inductor current;
- and
- a PWM comparator circuit connected to the synchronous-signal generator, generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the synchronous-signal generator comprises:
- a first low-pass filter connected to the phase node, generating a second signal synchronous and in phase with the inductor current;
- an error amplifier connected to the first low-pass filter and the PWM comparator circuit, receiving the second signal at a negative input terminal and a reference voltage at a positive input terminal to generate the first signal;
- and
- a second low-pass filter connected to the phase node and the error amplifier, filtering out an AC component of the phase-node voltage to generate the reference voltage.
A PWM controller for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM controller comprising:
- a synchronous-signal generator connected to the phase node, filtering out a high-frequency component of a phase-node voltage at the phase node to generate a first signal synchronous and out-of-phase with the inductor current;
- and
- a PWM comparator circuit connected to the synchronous-signal generator, generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the synchronous-signal generator comprises:
- a first low-pass filter connected to the phase node, generating a second signal synchronous and in phase with the inductor current;
- and
- an error amplifier connected to the first low-pass filter and the PWM comparator circuit, receiving the second signal at a negative input terminal and a first reference voltage at a positive input terminal to generate the first signal;
- wherein the error amplifier comprises a transconductance amplifier connected to the first low-pass filter, converting a difference between the second signal and the first reference voltage into a current as the first signal;
- wherein the PWM comparator circuit comprises:
- a resistor connected to the transconductance amplifier, generating a first voltage responsive to the first signal, to superimpose on a second reference voltage to generate a second voltage;
- and
- a comparator connected to the resistor, comparing the second voltage with the feedback signal to generate the PWM signal;
- wherein the first voltage is synchronous and out-of-phase with the inductor current.
A PWM controller for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM controller comprising:
- a synchronous-signal generator connected to the phase node, filtering out a high-frequency component of a phase-node voltage at the phase node to generate a first signal synchronous and out-of-phase with the inductor current;
- and
- a PWM comparator circuit connected to the synchronous-signal generator, generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the PWM comparator circuit comprise:
- an adder connected to the synchronous-signal generator, superimposing the first signal on a reference voltage to generate a third signal;
- and
- a comparator connected to the adder, receiving the third signal at a positive input terminal and the feedback signal at a negative input terminal to generate the PWM signal.
A PWM controller for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM controller comprising:
- a synchronous-signal generator connected to the phase node, filtering out a high-frequency component of a phase-node voltage at the phase node to generate a first signal synchronous and in phase with the inductor current;
- and
- a PWM comparator circuit connected to the synchronous-signal generator, generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the synchronous-signal generator comprises:
- a first low-pass filter connected to the phase node, generating a second signal synchronous and in phase with the inductor current;
- an error amplifier connected to the first low-pass filter and the PWM comparator circuit, receiving the second signal at a positive input terminal and a reference voltage at a negative input terminal to generate the first signal;
- and
- a second low-pass filter connected to the first low-pass filter and the error amplifier, filtering out an AC component of the second signal to generate the reference voltage.
A PWM controller for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM controller comprising:
- a synchronous-signal generator connected to the phase node, filtering out a high-frequency component of a phase-node voltage at the phase node to generate a first signal synchronous and in phase with the inductor current;
- and
- a PWM comparator circuit connected to the synchronous-signal generator, generating the PWM signal according to the first signal and a feedback signal related to output voltage;
- wherein the synchronous-signal generator comprises:
- a first low-pass filter connected to the phase node, generating a second signal synchronous and in phase with the inductor current;
- an error amplifier connected to the first low-pass filter and the PWM comparator circuit, receiving the second signal at a positive input terminal and a reference voltage at a negative input terminal to generate the first signal;
- and
- a second low-pass filter connected to the phase node and the error amplifier, filtering out an AC component of the phase-node voltage to generate the reference voltage.
A PWM controller for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM controller comprising:
- a synchronous-signal generator connected to the phase node, filtering out a high-frequency component of a phase-node voltage at the phase node to generate a first signal synchronous and in phase with the inductor current;
- and
- a PWM comparator circuit connected to the synchronous-signal generator, generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the synchronous-signal generator comprises:
- a first low-pass filter connected to the phase node, generating a second signal synchronous and in phase with the inductor current;
- and
- a transconductance amplifier connected to the first low-pass filter, converting a difference between the second signal and a first reference voltage into a current as the first signal;
- wherein the PWM comparator circuit comprises:
- a resistor connected to the transconductance amplifier, generating a first voltage responsive to the first signal, to superimpose on the feedback signal to generate a second voltage;
- and
- a comparator connected to the resistor, comparing the second voltage with a second reference voltage to generate the PWM signal;
- wherein the first voltage is synchronous and in phase with the inductor current.
A PWM controller for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM controller comprising:
- a synchronous-signal generator connected to the phase node, filtering out a high-frequency component of a phase-node voltage at the phase node to generate a first signal synchronous and in phase with the inductor current;
- and
- a PWM comparator circuit connected to the synchronous-signal generator, generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the PWM comparator circuit comprises:
- an adder connected to the synchronous-signal generator, superimposing the first signal on the feedback signal to generate a third signal;
- and
- a comparator connected to the adder, receiving the third signal at a negative input terminal and a reference voltage at a positive input terminal to generate the PWM signal.
A PWM control method for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM control method comprising:
- a.) filtering out a high-frequency component of a phase-node voltage at the phase node for generating a first signal synchronous and out-of-phase with the inductor current;
- and
- b.) generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the step a comprises:
- c.) filtering out the high-frequency component of the phase-node voltage for generating a second signal synchronous and in phase with the inductor current;
- d.) filtering out an AC component of the second signal for generating a reference voltage;
- and
- e.) amplifying a difference between the reference voltage and the second signal for generating the signal.
A PWM control method for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM control method comprising:
- a.) filtering out a high-frequency component of a phase-node voltage at the phase node for generating a first signal synchronous and out-of-phase with the inductor current;
- and
- b.) generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the step a comprises:
- c.) filtering out the high-frequency component of the phase-node voltage for generating a second signal synchronous and in phase with the inductor current;
- d.) filtering out an AC component of the phase-node voltage for generating a reference voltage;
- and
- e.) amplifying a difference between the reference voltage and the second signal for generating the first signal.
A PWM control method for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM control method comprising:
- a.) filtering out a high-frequency component of a phase-node voltage at the phase node for generating a first signal synchronous and out-of-phase with the inductor current;
- and
- b.) generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the step a comprises:
- c.) filtering out the high-frequency component of the phase-node voltage for generating a second signal synchronous and in phase with the inductor current;
- and
- d.) converting a difference between the second signal and a first reference voltage into a current as the first signal;
- wherein the step b comprises:
- responsive to the first signal, generating a first voltage synchronous and out-of-phase with the inductor current;
- superimposing the first voltage on a second reference voltage for generating a second voltage;
- and
- comparing the second voltage with the feedback signal for generating the PWM signal.
A PWM control method for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM control method comprising:
- a.) filtering out a high-frequency component of a phase-node voltage at the phase node for generating a first signal synchronous and out-of-phase with the inductor current;
- and
- b.) generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the step b comprises:
- superimposing the first signal on a reference voltage for generating a second signal;
- and
- comparing the second signal with the feedback signal for generating the PWM signal.
A PWM control method for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM control method comprising:
- a.) filtering out a high-frequency component of a phase-node voltage at the phase node for generating a first signal synchronous and in phase with the inductor current;
- and
- b.) generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the step a comprises:
- c.) filtering out the high-frequency component of the phase-node voltage for generating a second signal synchronous and in phase with the inductor current;
- d.) filtering out an AC component of the second signal for generating a reference voltage;
- and
- e.) amplifying a difference between the second signal and the reference voltage for generating the first signal.
A PWM control method for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM control method comprising:
- a.) filtering out a high-frequency component of a phase-node voltage at the phase node for generating a first signal synchronous and in phase with the inductor current;
- and
- b.) generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the step a comprises:
- c.) filtering out the high-frequency component of the phase-node voltage for generating a second signal synchronous and in phase with the inductor current;
- d.) filtering out an AC component of the phase-node voltage for generating a reference voltage;
- and
- e.) amplifying a difference between the second signal and the reference voltage for generating the first signal.
A PWM control method for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM control method comprising:
- a.) filtering out a high-frequency component of a phase-node voltage at the phase node for generating a first signal synchronous and in phase with the inductor current;
- and
- b.) generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the step a comprises:
- c.) filtering out the high-frequency component of the phase- node voltage for generating a second signal synchronous and in phase with the inductor current;
- and
- d.) converting a difference between the second signal and a first reference voltage into a current as the first signal;
- wherein the step b comprises:
- responsive to the first signal, generating a first voltage synchronous and in phase with the inductor current;
- superimposing the first voltage on the feedback signal for generating a second voltage;
- and
- comparing the second voltage with a second reference voltage for generating the PWM signal.
A PWM control method for a DC-DC voltage converter having at least one pair of high-side and low-side elements connected by a phase node and switched by a PWM signal to control an inductor current to charge an output capacitor to generate an output voltage, the PWM control method comprising:
- a.) filtering out a high-frequency component of a phase-node voltage at the phase node for generating a first signal synchronous and in phase with the inductor current;
- and
- b.) generating the PWM signal according to the first signal and a feedback signal related to the output voltage;
- wherein the step b comprises:
- superimposing the first signal on the feedback signal for generating a second signal;
- and
- comparing the second signal with a reference voltage for generating the PWM signal.
Dependencies are inferred from the claim text.