Mixed-mode power converter control

Patent metadata

Field	Value
Publication number	US-11689101-B2
Application number	US-202017096820-A
Country	US
Kind code	B2
Filing date	Nov 12, 2020
Priority date	Nov 12, 2020
Publication date	Jun 27, 2023
Grant date	Jun 27, 2023

Abstract

Circuits and methods for adding a Current Mode signal into a Voltage Mode controller for fixed-frequency DC-to-DC power converters. A current-controlled voltage source (CCVS) generates a voltage proportional to the power converter output current, which voltage is combined with a comparison signal generated by comparing a target output voltage to the actual output voltage. The modified comparison signal generates a pulse-width modulation control signal that regulates the power converter output as a function of output voltage and some portion of output current. With the addition of an inductor current signal into the controller Voltage Mode feedback loop, the double pole predominant in constant conduction mode (CCM) mode can be smoothed over to improve stability, while discontinuous conduction mode (DCM) loop response is largely unchanged with or without the added Current Mode signal. Embodiments enable simplified compensation while covering a wider operating range.

First claim

What is claimed is:

1. A controller for a power converter controlled by a pulse-width modulation (PWM) control signal, the controller including:
(a) a comparison circuit configured to be coupled to a voltage representative of an output voltage of the power converter and to a target voltage, and to output a comparison signal indicative of a difference between the coupled voltages;
(b) a modifier circuit configured to be coupled to the power converter, and configured to combine a (1) a proportional voltage that is proportional to a representative high-frequency filtered current of the power converter, wherein the representative high-frequency filtered current is time-varying and the proportional voltage is only generated in significant amounts when a frequency of the time-varying representative high-frequency filtered current is not filtered out, and (2) the comparison signal output from the comparison circuit as a modified comparison signal; and
(c) a comparator, having a first input coupled to the modified comparison signal and a second input configured to be coupled to a periodic voltage signal, for generating an output comprising the PWM control signal as a function of the output voltage of the power converter and the representative high-frequency filtered current of the power converter.

2. The invention of claim 1 , further including a scaling circuit coupled to the comparison circuit and configured to be coupled to the output voltage of the power converter, the scaling circuit configured to provide a scaled version of the output voltage to the comparison circuit.

3. The invention of claim 1 , further including a compensation circuit coupled to the output of the comparison circuit and configured to stabilize a closed-loop response of the controller.

4. The invention of claim 1 , wherein the modifier circuit includes an adjustable gain.

5. A controller for a power converter configured to generate an output voltage in response to a pulse-width modulation (PWM) control signal, the controller including:
(a) an error amplifier configured to be coupled to a voltage representative of the output voltage of the power converter and to a target voltage, and to output a comparison signal indicative of a difference between the coupled voltages;
(b) a current-controlled voltage source configured to be coupled to the power converter, and configured to output a modified comparison signal comprising a combination of (1) a proportional voltage that is proportional to certain bandpass-limited frequencies of a representative current of the power converter, wherein the representative current is time-varying and the proportional voltage is only generated in significant amounts when a frequency of the time-varying representative current is within the certain bandpass-limited frequencies, and (2) the comparison signal output from the error amplifier; and
(c) a comparator, having a first input coupled to the modified comparison signal and a second input configured to be coupled to a periodic voltage signal, configured to output the PWM control signal based on a comparison of the periodic voltage signal and the modified comparison signal.

6. The invention of claim 5 , further including a scaling circuit coupled to the error amplifier and configured to be coupled to the output voltage of the power converter, the scaling circuit configured to generate a scaled version of the output voltage as the voltage representative of the output voltage of the power converter.

7. The invention of claim 5 , further including a compensation circuit coupled to the output of the error amplifier and configured to stabilize a closed-loop response of the controller.

8. The invention of claim 5 , wherein the current-controlled voltage source includes an adjustable gain.

9. A controller for a power converter controlled by a pulse-width modulation (PWM) control signal and configured to receive an input voltage V IN and generate an output voltage V OUT different from V IN , the controller including:
(a) a comparison circuit configured to be coupled to a voltage representative of an output voltage of a power converter and to a target voltage, and to output a comparison signal indicative of a difference between the coupled voltages;
(b) a modifier circuit configured to be coupled to the power converter, and configured to output a modified comparison signal comprising a combination of a voltage proportional to a representative current of the power converter and the comparison signal output from the comparison circuit, wherein the modifier circuit includes a bandpass filter configured to generate the voltage proportional to the representative current only for certain frequencies of the representative current;
(c) a voltage generator configured to output a periodic voltage signal; and
(d) a comparator, having a first input coupled to the modified comparison signal and a second input coupled to the voltage generator, configured to output the PWM control signal based on a comparison of the periodic voltage signal and the modified comparison signal.

10. The invention of claim 9 , further including a scaling circuit coupled to the comparison circuit and to the output voltage of the power converter, the scaling circuit configured to generate a scaled version of the output voltage as the voltage representative of the output voltage of the power converter.

11. The invention of claim 9 , further including a compensation circuit coupled to the output of the comparison circuit and configured to stabilize a closed-loop response of the power converter.

12. The invention of claim 9 , wherein the modifier circuit includes an adjustable gain.

13. The invention of claim 9 , wherein the power converter is a DC-to-DC power converter configured to generate an output voltage from an input voltage, the output voltage having a value different from the input voltage.

14. The invention of claim 13 , wherein the DC-to-DC power converter is a fixed-frequency switched inductor-capacitor DC-to-DC power converter.

Assignees

• Psemi Corp

Inventors

• Zanchi Brian
• Yu Tim Wen Hui
• Szczeszynski Gregory

Classifications

• H02M1/0009

  Devices or circuits for detecting current in a converter · CPC title

• H02M3/158 Primary

  including plural semiconductor devices as final control devices for a single load · CPC title

• H02M1/0025

  Arrangements for modifying reference values, feedback values or error values in the control loop of a converter · CPC title