Frequency detection to perform adaptive peak current control

• US 10,622,892 B2
• Filed: 05/07/2019
• Issued: 04/14/2020
• Est. Priority Date: 12/16/2016
• Status: Active Grant

• Current Assignee: STMicroelectronics International N.V. (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Asia Pacific Pte Limited (STMicroelectronics NV)
• Inventors: Leong, Kong Yin
• Primary Examiner(s): Pham, Emily P
• Application Number:
  US16/405,861
• Publication Number:
  US 20190267899A1
• Time in Patent Office: 343 Days
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/0019 the disturbance parameters being load current fluctuations
• CPC Class Codes: H02M 1/088 for the simultaneous control of series or parallel connected semiconductor devices
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load

Abstract

The amount of power being output to the load is sensed by sampling the frequency of the pulse width modulation signal that is controlling the switch that is providing the power to the load. If the pulse width modulation signal has a high frequency, then it will be providing higher power to the load. As the power drawn by the load decreases, the frequency of the pulse width modulation power supply signal will decrease. By sensing and periodically sampling the frequency of the pulse width modulation signal that is providing power, the demand of the load can be quickly and accurately determined. As the power demand of the load decreases, the peak current that the power supply switch can provide also decreases. The permitted peak current dynamically changes to adapt to the power drawn by the load.

Claims

1. A method, comprising:

controlling timing on an on/off state of a switch circuit using a variable frequency control signal;

supplying power at a first value to a load through the switch circuit based on the timing of the on/off state of the switch circuit;

detecting a frequency value of the variable frequency control signal;

comparing a signal corresponding to the frequency value of the variable frequency control signal that controls the on/off state of the switch circuit with a reference signal value;

adjusting the frequency value of the variable frequency control signal to become an adjusted frequency value based on a result of the comparing with the reference signal value; and

supplying power at a second value to the load through the switch circuit based on adjusted timing of the on/off state of the switch circuit controlled using the adjusted frequency value of the variable frequency control signal.

2. The method of claim 1, wherein the signal corresponding to the frequency value is a current signal associated to a voltage signal converted from the frequency value.

3. The method of claim 1, wherein the signal corresponding to the frequency value is a voltage signal that is converted from the frequency value.

4. The method of claim 1, wherein the adjusting the frequency value of the variable frequency control signal further includes clamping the frequency value of the variable frequency control signal to a threshold value.

5. The method of claim 4, further comprising stabilizing the threshold value, the stabilizing preventing the threshold value from going below a selected value.

6. The method of claim 1, wherein the comparing the signal corresponding to the frequency value of the variable frequency control signal with the reference signal value includes adjusting the reference signal value.

7. A method, comprising:

coupling a load to a power supply through a switch circuit, the switch circuit configured to switch based on a control signal having a frequency;

detecting a first value of a power provided to the load through the switch circuit;

comparing the first value of the power with a reference power;

adjusting the frequency of the control signal to become an adjusted frequency based on the comparing the first value of the power with the reference power; and

supplying the power with a second value to the load based on the adjusted frequency of the control signal.

8. The method of claim 7, wherein the adjusting the frequency of the control signal including:

detecting the frequency of the control signal;

converting the frequency into a voltage signal;

comparing the voltage signal to a reference voltage; and

adjusting the reference voltage based on the comparing the first value of the power with the reference power.

9. The method of claim 8, wherein the adjusting the reference voltage includes:

reducing the reference voltage if the first value of the power is smaller than a first reference value of the reference power; and

increasing the reference voltage if the first value of the power is larger than a second reference value of the reference power.

10. The method of claim 8, further comprising:

stabilizing the reference voltage using a stabilization circuit that includes a sample and hold circuit.

11. A circuit, comprising:

a switch circuit coupled between a load and a power supply;

a control unit that provides a control signal to the switch circuit, the control signal having a frequency component;

a frequency sensing unit that detects the frequency component of the control signal and converts the frequency component to a voltage signal; and

a feedback circuit that adjusts the frequency component of the control signal to become an adjusted frequency component based on comparing the voltage signal to a reference voltage value and supplies the adjusted frequency component of the control signal to the control unit for the control unit to provide an adjusted control signal to the switch circuit.

12. The circuit of claim 11, wherein the switch circuit is part of a power regulation circuit coupled between the load and the power supply.

13. The circuit of claim 12, wherein an output power of the power regulation circuit varies with the frequency component of the control signal.

14. The circuit of claim 13, further comprising a load feedback unit coupled to detect the output power of the power regulation circuit.

15. The circuit of claim 14, wherein the load feedback circuit provides a feedback signal to the control unit based on the output power.

16. The circuit of claim 14, wherein the load feedback unit includes a voltage divider.

17. The circuit of claim 14, wherein the load feedback unit includes a comparator that compares the output power with a reference power value.

18. The circuit of claim 11, wherein the frequency sensing unit includes a mirroring transistor.

19. The circuit of claim 11, wherein the feedback circuit is configured to compare the voltage signal with a reference voltage to generate a signal to the control unit.

20. The circuit of claim 11, wherein the control unit includes a power termination circuit which outputs a termination signal to turn off the switch circuit when the voltage signal meets a threshold value.