System and Method for a Switched-Mode Power Supply

Patent metadata

Field	Value
Publication number	US-2016141964-A1
Application number	US-201514929029-A
Country	US
Kind code	A1
Filing date	Oct 30, 2015
Priority date	Nov 17, 2014
Publication date	May 19, 2016
Grant date	—

Abstract

In accordance with an embodiment, a method of operating a power supply includes detecting a loss of at least one of an AC input voltage an AC input power at an input of the power supply, and increasing a switching frequency of the power supply upon detection of the loss of the AC input voltage or AC input power.

First claim

What is claimed is:

1 . A method of operating a power supply comprising:
detecting a loss of at least one of an AC input voltage an AC input power at an input of the power supply; and increasing a switching frequency of the power supply upon detection of the loss of the AC input voltage or AC input power.

2 . The method of claim 1 , further comprising detecting a transient voltage drop at an output of the power supply and initiating a shutdown procedure upon detection of the transient voltage drop.

3 . A method of operating a switched-mode power supply having a AC/DC converter followed by a DC/DC converter, the method comprising:
operating the switched-mode power supply in a normal operation mode comprising providing a first switching signal to the AC/DC converter and providing a second switching signal to the DC/DC converter; detecting a loss of an AC input signal coupled to an input of the AC/DC converter; and after detecting the loss of the AC input signal, deactivating the first switching signal and increasing a frequency of the second switching signal.

4 . The method of claim 3 , wherein increasing the frequency of the second switching signal comprises increasing the frequency of the second switching signal to a predetermined switching frequency.

5 . The method of claim 4 , wherein the increasing the frequency of the second switching signal causes a transient decrease in voltage at an output of the DC/DC converter.

6 . The method of claim 5 , further comprising detecting the transient decrease in voltage at the output of the DC/DC converter.

7 . The method of claim 6 , further comprising disconnecting loads coupled to at least one output of the DC/DC converter upon detecting the transient decrease in voltage.

8 . The method of claim 6 , further comprising performing a shutdown procedure in a circuit that receives power from an output of the DC/DC converter up detecting the transient decrease in voltage.

9 . The method of claim 8 , further comprising providing power to the circuit that receives power from the output of the DC/DC converter using a voltage regulator coupled between the output of the DC/DC converter and the circuit.

10 . The method of claim 8 , wherein performing the shutdown procedure comprises writing data to a memory.

11 . The method of claim 3 , wherein the DC/DC converter comprises a resonant power converter.

12 . The method of claim 11 , wherein the resonant power converter comprises an inductor-inductor-capacitor (LLC) power converter.

13 . The method of claim 11 , wherein the AC/DC converter comprises a power factor correction (PFC) circuit.

14 . The method of claim 3 , wherein detecting the loss of the AC input signal comprises detecting a loss of a rectified AC input signal.

15 . The method of claim 3 , wherein detecting the loss of the AC input signal comprises:
comparing an output voltage of the DC/DC converter with a predetermined threshold; and determining that the AC input signal is lost when the output voltage of the DC/DC converter falls below the predetermined threshold.

16 . The method of claim 3 , wherein detecting the loss of the AC input signal comprises
detecting a loss of a rectified AC input signal; comparing an output voltage of the DC/DC converter with a predetermined threshold; and determining that the AC input signal is lost when both of the rectified AC input signal is lost based on the detecting and when the output voltage of the DC/DC converter falls below the predetermined threshold based on the comparing.

17 . The method of claim 3 , further comprising deactivating the second switching signal a first time delay after the step of increasing the frequency of the second switching signal.

18 . The method of claim 17 , wherein deactivating the second switching signal comprises using a counter to produce the first time delay.

19 . The method of claim 3 , wherein the AC input signal comprises at least one of an AC input voltage or an AC input power.

20 . A system comprising:
a pulse generator configured to provide a first switching signal to an AC/DC converter, and a second switching signal to a DC/DC converter having an input coupled to an output of the AC/DC converter; and control circuit configured to
detect a loss of an AC input signal coupled to an input of the AC/DC converter; and
after detecting the loss of the AC input signal, deactivating the first switching signal and increasing a frequency of the second switching signal.

21 . The system of claim 20 , further comprising the AC/DC converter and the DC/DC converter.

22 . The system of claim 21 , wherein the DC/DC converter comprises a resonant power converter.

23 . The system of claim 22 , wherein the AC/DC converter comprises a power factor correction (PFC) circuit.

24 . The system of claim 20 , further comprising:
a further power converter having an input coupled to an output of the DC/DC converter; and a further circuit having a power input coupled to an output of the further power converter, wherein the further circuit is configured to detect a transient voltage drop at the output of the DC/DC converter when the frequency of the second switching signal is increased, and initiate a shutdown procedure upon detection of the transient voltage drop.

25 . The system of claim 24 , further comprising a switch coupled between the output of the DC/DC converter and a load port, wherein the switch comprises a control terminal coupled to an output of the further circuit.

26 . The system of claim 25 , wherein the further circuit is configured to open the switch via the control terminal upon detection of the transient voltage drop.

27 . The system of claim 20 , wherein the AC input signal comprises an AC input voltage or an AC input power.

Assignees

• Infineon Technologies Austria

Inventors

• Yu Weifu
• Agarwal Nitin
• Mao Mingping
• Zhang Guoxing

Classifications

• Y02B70/10

  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 · CPC title

• H02M3/28 Primary

  using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC · CPC title

• H02M1/36

  Means for starting or stopping converters · CPC title

• H02M3/33507 Primary

  with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence) · CPC title

• H02M1/4225

  using a non-isolated boost converter · CPC title