Output switching circuit

• US 9,502,979 B2
• Filed: 01/16/2015
• Issued: 11/22/2016
• Est. Priority Date: 08/31/2010
• Status: Active Grant

• Current Assignee: Monterey Research, LLC (Vector Capital Corporation)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Yoshioka, Akihito, Wakii, Takeshi
• Primary Examiner(s): Patel, Rajnikant
• Application Number:
  US14/598,647
• Publication Number:
  US 20150130430A1
• Time in Patent Office: 676 Days
• Field of Search: 323/207, 323/222, 323/224, 323/271, 323/272, 323282-289, 363/89, 363/97, 363/98
• US Class Current: 1/1
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 3/1588 comprising at least one synchronous rectifier element H02M3/1582, H02M3/1584 take precedence
• CPC Class Codes: H03K 17/6872 using complementary field-effect transistors
• 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

An output switching circuit includes a switching circuit having a first transistor connected to a high-voltage power supply, a second transistor connected to a low-voltage power supply, and an output s terminal at a connection node between the first and second transistors; a comparison unit that compares an input signal with a feedback signal obtained by feedback of an output signal of the output terminal via a low-pass filter to generate a comparison signal; and a drive pulse generating unit that generates first drive pulses for driving the first transistor and second drive pulses for driving the second transistor in accordance with the comparison signal.

Claims

1. A comparison unit for a switching circuit, comprising:

a comparator configured to compare an input signal with a feedback signal to provide a first signal;

a sampling circuit configured to sample the first signal according to a reference clock to provide a sampling signal, the sampling signal having a first level or a second level; and

a comparison signal generating circuit configured to provide a comparison signal having the first level when the sampling signal is at the first level for a longer time duration than the second level or having the second level when the sampling signal is at the first level for a shorter time duration than the second level.

2. The comparison unit of claim 1, wherein the switching circuit is configured to switch an output signal between the first level and the second level when the comparison signal transitions between the first level and the second level.

3. The comparison unit of claim 2, wherein the switching circuit is configured to switch the output signal synchronously with the reference clock.

4. The comparison unit of claim 1, wherein the switching circuit comprises:

a first transistor configured to provide the output signal at the first level when the comparison signal is at the first level; and

a second transistor, coupled to the first transistor, configured to provide the output signal at the second level when the comparison signal is at the second level.

5. The comparison unit of claim 2, wherein the feedback signal is based upon the output signal.

6. The comparison unit of claim 5, wherein the feedback signal is a representation of the output signal that has been low pass filtered.

7. The comparison unit of claim 1, wherein the first level of the comparison signal indicates that a voltage of the input signal is higher than a voltage of the feedback signal, and

wherein the second level of the comparison signal indicates that the voltage of the input signal is lower than the voltage of the feedback signal.

8. A method for switching a switching circuit, comprising:

comparing an input signal with a feedback signal to provide a first signal;

sampling the first signal according to a reference clock to provide a sampling signal, the sampling signal having a first level or a second level;

providing a comparison signal having the first level when the sampling signal is at the first level for a longer time duration than the second level or having the second level when the sampling signal is at the first level for a shorter time duration than the second level; and

switching an output signal of the switching circuit between the first level and the second level when the comparison signal transitions between the first level and the second level.

9. The method of claim 8, wherein the switching comprises:

switching the output signal synchronously with the reference clock.

10. The method of claim 8, wherein the switching comprises:

activating a first transistor to provide the output signal at the first level when the comparison signal is at the first level; and

activating a second transistor, coupled to the first transistor, to provide the output signal at the second level when the comparison signal is at the second level.

11. The method of claim 8, wherein the feedback signal is based upon the output signal.

12. The method of claim 8, wherein the feedback signal is a representation of the output signal that has been low pass filtered.

13. The method of claim 8, wherein the first level of the comparison signal indicates that a voltage of the input signal is higher than a voltage of the feedback signal, and

wherein the second level of the comparison signal indicates that the voltage of the input signal is lower than the voltage of the feedback signal.

14. A comparison unit for a switching circuit, comprising:

means for comparing an input signal with a feedback signal to provide a first signal;

means for sampling the first signal according to a reference clock to provide a sampling signal, the sampling signal having a first level or a second level; and

means for providing a comparison signal having the first level when the sampling signal is at the first level for a longer time duration than the second level or having the second level when the sampling signal is at the first level for a shorter time duration than the second level.

15. The comparison unit of claim 14, wherein the switching circuit is configured to switch an output signal between the first level and the second level when the comparison signal transitions between the first level and the second level.

16. The comparison unit of claim 15, wherein the switching circuit is configured to switch the output signal synchronously with the reference clock.

17. The comparison unit of claim 14, wherein the switching circuit comprises:

a first transistor configured to provide the output signal at the first level when the comparison signal is at the first level; and

a second transistor, coupled to the first transistor, configured to provide the output signal at the second level when the comparison signal is at the second level.

18. The comparison unit of claim 15, wherein the feedback signal is based upon the output signal.

19. The comparison unit of claim 18, wherein the feedback signal is a representation of the output signal that has been low pass filtered.

20. The comparison unit of claim 14, wherein the first level of the comparison signal indicates that a voltage of the input signal is higher than a voltage of the feedback signal, and

wherein the second level of the comparison signal indicates that the voltage of the input signal is lower than the voltage of the feedback signal.