System and method for smoothing mode transitions in a voltage supply

• US 8,373,400 B2
• Filed: 09/07/2010
• Issued: 02/12/2013
• Est. Priority Date: 09/15/2009
• Status: Expired due to Fees

• Current Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Original Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Inventors: Qiu, Weihong, Liu, Jun, Xiao, Shangyang
• Primary Examiner(s): Berhane, Adolf
• Assistant Examiner(s): Quddus, Nusrat
• Application Number:
  US12/876,299
• Publication Number:
  US 20110062926A1
• Time in Patent Office: 889 Days
• Field of Search: 323223-224, 323243-244, 323/246, 323266-271, 323282-286, 323/288, 323/351, 323/356
• US Class Current: 323/282
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H02M 3/1588 comprising at least one synchronous rectifier element H02M3/1582, H02M3/1584 take precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A system, voltage supply circuit, control unit for a voltage supply circuit, and method of controlling a voltage supply circuit are disclosed. For example, a system is disclosed that comprises at least one electronic circuit and a voltage supply unit coupled to an input of the at least one electronic circuit. The voltage supply unit includes a power unit to supply a voltage to the at least one electronic circuit and a control unit to control an operating mode of the power unit, an output of the control unit coupled to an input of the power unit. The control unit includes a mode selector to select the operating mode of the power unit, coupled to at least a first output of the power unit, an amplifier coupled to the at least a first output of the power unit, a compensation circuit, and a first switching unit coupled to the mode selector and the compensation circuit, to couple the compensation circuit to the amplifier if a selected operating mode of the power unit is a first mode.

Claims

1. A system, comprising:

at least one electronic circuit; and

a voltage supply unit coupled to an input of the at least one electronic circuit, the voltage supply unit including;

a power unit to supply a voltage to the at least one electronic circuit; and

a control unit to control an operating mode of the power unit, an output of the control unit coupled to an input of the power unit, the control unit including;

a mode selector to select the operating mode of the power unit, coupled to at least a first output of the power unit;

an amplifier coupled to the at least a first output of the power unit;

a compensation circuit;

a signal comparator coupled to the mode selector and the at least a first output of the power unit, to compare the at least a first output of the power unit to a threshold signal; and

a first switching unit coupled to the mode selector, the signal comparator and the compensation circuit, to couple the compensation circuit to the amplifier if a selected operating mode of the power unit is a first mode, and a value of the at least a first output of the power unit is not equal to a value of the threshold signal.

2. The system of claim 1, wherein the first mode is a Pulse Frequency Modulation (PFM) mode.

3. The system of claim 1, wherein the at least a first output of the power unit is a voltage output.

4. The system of claim 1, wherein the mode selector is further coupled to a second output of the power unit.

5. The system of claim 1, wherein the mode selector is further coupled to a second output of the power unit, and the second output of the power unit is a current output.

6. The system of claim 1, wherein the first switching unit is enabled to decouple the compensation circuit from the amplifier if the selected operating mode is a Pulse Width Modulation (PWM) mode.

7. The system of claim 1, wherein the amplifier is further coupled to a reference voltage supply, and an output of the amplifier is a value associated with a difference between a value of the reference voltage supply and a value of the first output of the power unit.

8. The system of claim 1, wherein the voltage supply unit is implemented utilizing at least one Integrated Circuit (IC).

9. The system of claim 1, wherein the at least one electronic circuit is one or more of a Central Processing Unit (CPU), multiprocessor unit, Random Access Memory (RAM), Read Only Memory (ROM), hard drive, mass storage unit, display unit, Input/Output (I/O) unit, transmitting unit, receiving unit, Intermediate Frequency (IF) unit, signal processing unit, audio processor unit, data processor unit, communication bus, or rechargeable battery.

10. A voltage supply circuit, comprising:

a power unit to output a Direct Current (DC) voltage, the power unit including an inductor and at least one transistor to charge or discharge the inductor; and

a control unit to control an operating mode of the power unit, coupled to the at least one transistor, the control unit including;

a mode selector to receive at least one of a voltage signal and a current signal associated with a current flow through the inductor, and select at least one of a Pulse Width Modulation (PWM) mode and a Pulse Frequency Modulation (PFM) mode of operation of the power unit responsive to the at least one of a voltage signal and a current signal;

an amplifier to receive a reference voltage signal and the voltage signal, and output a signal associated with a difference between a value of the reference voltage signal and a value of the voltage signal;

a compensation circuit to smooth a mode transition of the power unit to at least one of the PWM mode and the PFM mode;

a signal comparator to receive the voltage signal and compare the voltage signal to a threshold signal, coupled to the mode selector; and

a first switching unit coupled to the mode selector, the signal comparator and the compensation circuit, to couple the compensation circuit to the amplifier if a selected operating mode of the power unit is a first mode, and a value of the voltage signal is not equal to a value of the threshold signal.

11. The voltage supply circuit of claim 10, wherein the first mode is the PFM mode.

12. The voltage supply circuit of claim 10, wherein the voltage signal is a voltage feedback signal and the current signal is proportional to the current flow through the inductor.

13. The voltage supply circuit of claim 10, further comprising the signal comparator to receive the voltage signal and responsive to the voltage signal and the mode selector, couple and decouple the compensation circuit to and from the amplifier if the first mode is the PFM mode.

14. The voltage supply circuit of claim 10, wherein the at least one transistor is a Metal-Oxide Semiconductor Field Effect Transistor (MOSFET).

15. The voltage supply circuit of claim 10, wherein the voltage supply circuit is implemented utilizing a Complementary MOS (CMOS) manufacturing technology.

16. The voltage supply circuit of claim 10, wherein the voltage supply circuit is implemented in an IC.

17. The voltage supply circuit of claim 10, wherein a value of the voltage signal and a value of the current signal are associated with a value of an output load on the power unit.

18. The voltage supply circuit of claim 10, wherein the voltage supply circuit is a switching voltage regulator.

19. The voltage supply circuit of claim 10, wherein the voltage supply circuit is a switched-mode power supply.

20. A control unit for a voltage supply circuit, comprising:

a mode selector to select an operating mode of the voltage supply circuit, coupled to a first output of the voltage supply circuit;

an amplifier coupled to the first output of the voltage supply circuit;

a compensation circuit;

a signal comparator coupled to the mode selector and the first output of the voltage supply circuit, to compare the first output of the voltage supply circuit to a threshold signal; and

a first switching unit coupled to the mode selector and the compensation circuit, to couple the compensation circuit to the amplifier if a selected operating mode of the voltage supply circuit is a first mode, and a value of the first output of the voltage supply circuit is not equal to a value of the threshold signal.

21. The control unit of claim 20, wherein the first mode is a PFM mode.

22. The control unit of claim 20, wherein the first output of the voltage supply circuit is a voltage output.

23. The control unit of claim 20, wherein the mode selector is further coupled to a second output of the voltage supply circuit.

24. The control unit of claim 20, wherein the mode selector is further coupled to a second output of the voltage supply circuit, and the second output of the voltage supply circuit is a current output.

25. The control unit of claim 20, wherein the first switching unit is enabled to decouple the compensation circuit from the amplifier if the selected operating mode is a PWM mode.

26. The control unit of claim 20, wherein the amplifier is further coupled to a reference voltage supply, and an output of the amplifier is a value associated with a difference between a value of the reference voltage supply and a value of the first output of the voltage supply circuit.

27. The control unit of claim 20, wherein the control unit is implemented utilizing an IC.

28. A method of controlling a voltage supply circuit, comprising:

receiving a voltage signal and a current signal associated with a current flow through an inductor in the voltage supply circuit;

selecting at least one of a PWM mode and a PFM mode of operation of the voltage supply circuit responsive to the voltage signal and the current signal;

comparing the voltage signal with a threshold signal; and

smoothing a transition of the voltage supply circuit to the PWM mode of operation if a value of the voltage signal is not equal to a value of the threshold signal.

29. The method of claim 28, further comprising:

coupling a compensation circuit to the voltage supply circuit if the voltage supply circuit is operating in the PFM mode.

30. The method of claim 28, wherein the receiving, selecting and smoothing are performed in an IC.