Control circuits and methods for regulating output voltages

Patent metadata

Field	Value
Publication number	US-11923779-B2
Application number	US-202017054232-A
Country	US
Kind code	B2
Filing date	Nov 5, 2020
Priority date	Nov 5, 2020
Publication date	Mar 5, 2024
Grant date	Mar 5, 2024

Abstract

A method of regulating an output voltage of a switched mode power supply having a variable input voltage and at least one power switch is provided. The method includes generating a control signal for the at least one power switch of the switched mode power supply based at least in part on a control voltage, the control signal having a duty cycle. The method also includes generating a reference voltage based at least in part on the duty cycle of the control signal and a maximum duty cycle, and generating the control voltage based at least in part on the reference voltage and the output voltage.

First claim

What is claimed is:

1. A method of regulating an output voltage of a switched mode power supply having a variable input voltage and at least one power switch, the method comprising:
generating a control signal for the at least one power switch of the switched mode power supply based at least in part on a control voltage, the control signal having a duty cycle;
generating an output signal based at least in part on a comparison of the duty cycle of the control signal with a maximum duty cycle;
comparing the output signal with a comparison value;
generating a delta reference voltage signal based on the comparison of the output signal with the comparison value;
generating a reference voltage based on a comparison of the delta reference voltage signal with a maximum output voltage reference signal; and
generating the control voltage based at least in part on the reference voltage and the output voltage of the switched mode power supply;
wherein generating the delta reference voltage signal comprises setting the delta reference voltage signal equal to a difference between the output signal and the comparison value based on the difference being greater than zero; and
wherein generating the delta reference voltage signal comprises setting the delta reference voltage signal equal to zero based on the difference between the output signal and the comparison value being less than zero.

2. The method of claim 1 , wherein the control voltage is generated by an output voltage feedback and compensation circuit.

3. The method of claim 1 , wherein the control voltage is based at least in part on a difference between the reference voltage and the output voltage.

4. The method of claim 3 , wherein the control voltage is generated by a differential amplifier.

5. The method of claim 1 , wherein the control signal is a square wave.

6. A control circuit for regulating an output voltage of a switched mode power supply having a variable input voltage and at least one power switch, the control circuit configured to:
generate a control signal for the at least one power switch of the switched mode power supply based at least in part on a control value, the control signal having a duty cycle;
generate an output signal value based at least in part on a comparison of the duty cycle of the control signal with a maximum duty cycle;
compare the output signal value with a comparison value;
generate a delta reference voltage signal based on the comparison of the output signal value with the comparison value;
generate a reference voltage based on a comparison of the delta reference voltage signal with a maximum output voltage reference signal; and
generate the control value based at least in part on a difference between the reference voltage and the output voltage of the switched mode power supply;
wherein the control circuit, in being configured to generate the delta reference voltage signal, is configured to set the delta reference voltage signal equal to a difference between the output signal value and the comparison value based on the difference being greater than zero; and
wherein the control circuit is further configured to set the delta reference voltage signal equal to zero based on the difference between the output signal value and the comparison value being less than zero.

7. The control circuit of claim 6 , wherein the control circuit comprises a digital control circuit.

8. The control circuit of claim 7 , wherein the control signal is generated by a pulse-width-modulation (PWM) digital controller.

9. The control circuit of claim 7 , wherein the control circuit comprises a microcontroller.

10. The control circuit of claim 7 , wherein the control circuit comprises a proportional-integral-derivative (PID) duty regulator module, and a PID voltage regulator module.

11. A switched mode power supply comprising a power circuit and a control circuit, wherein the control circuit is configured to:
generate a control signal for at least one power switch of the switched mode power supply based at least in part on a control voltage, the control signal having a duty cycle;
generate an output signal based at least in part on the duty cycle of the control signal and a maximum duty cycle;
compare the output signal with a comparison value;
generate a delta reference voltage signal based on the comparison of the output signal with the comparison value;
generate a reference voltage based on a comparison of the delta reference voltage signal with a maximum output voltage reference signal; and
generate the control voltage based at least in part on a difference between the reference voltage and an output voltage of the switched mode power supply;
wherein the control circuit, in being configured to generate the delta reference voltage signal, is configured to set the delta reference voltage signal equal to a difference between the output signal and the comparison value based on the difference being greater than zero; and
wherein the control circuit is further configured to set the delta reference voltage signal equal to zero based on the difference between the output signal and the comparison value being less than zero.

12. The switched mode power supply of claim 11 , wherein the power circuit comprises an isolation transformer.

13. The switched mode power supply of claim 11 , wherein the control circuit comprises a primary side and a secondary side, and the primary side is coupled with the secondary side by two or more optical couplers.

14. The switched mode power supply of claim 11 , wherein the power circuit comprises two or more power circuits.

Assignees

• Astec Int Ltd

Inventors

• Zhang Bing
• Liang Lian
• Qin Mei
• Fan Xiaodong
• Wang Guozhen

Classifications

• H02M3/33592 Primary

  having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer · CPC title

• H02M1/0025 Primary

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

• H02M3/158

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