Method and apparatus to control either a regulated or an unregulated output of a switching power supply

• US 7,272,025 B2
• Filed: 01/18/2005
• Issued: 09/18/2007
• Est. Priority Date: 01/18/2005
• Status: Expired due to Fees

• Current Assignee: Power Integrations Incorporated
• Original Assignee: Power Integrations Incorporated
• Inventors: Hawley, Stephen W.
• Primary Examiner(s): Easthom; Karl
• Assistant Examiner(s): BEHM, HARRY RAYMOND
• Application Number:
  US11/038,625
• Publication Number:
  US 20060158909A1
• Time in Patent Office: 973 Days
• Field of Search: 323/284, 323/282, 323/901, 363/21.12, 363/21.13, 363 2117- 2118, 363/49, 320/160
• US Class Current: 363/49
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence

Abstract

Techniques are disclosed to control output power from a switching power supply. For example, a switching regulator according to aspects of the present invention includes a switch to be coupled to an energy transfer element of a power supply. A controller is coupled to the switch to control a switching of the switch to regulate an output voltage and an output current at an output of power supply output. A feedback circuit is coupled to the controller. The feedback circuit is coupled to receive a feedback signal from the output of the power supply. Combinations of the output voltage and the output current correspond to output regions. There is at least one regulated output region and one unregulated output region. At least one unregulated output region is a self protection auto-restart region. Within at least one unregulated output region, the switching regulator provides continuous output power at substantially the maximum output power of the switching regulator. Each output region corresponds to a magnitude and duration of the feedback signal.

Claims

1. A switching regulator, comprising:

a switch to be coupled to an energy transfer element of a power supply;

a controller coupled to the switch to control a switching of the switch to control an output of the power supply, wherein the output of the power supply includes a combination of an output voltage and an output current; and

a feedback circuit coupled to the controller, the feedback circuit coupled to receive a feedback-signal derived from the output of the power supply, wherein combinations of the output voltage and the output current correspond to either regulated or unregulated output regions in which the power supply can operate, wherein at least one unregulated output region is a self protection auto-restart region where the power supply operates at a reduced output voltage and reduced average output current and where the controller continuously cycles between a first period of unregulated switching of the switch and a second period of no switching of the switch while in the auto-restart region, wherein within another unregulated output region the switching regulator provides continuous output power at substantially the maximum output power of the switching regulator, and wherein a magnitude of the feedback signal corresponds to one of the regulated or unregulated output regions in which the power supply can operate.

2. The switching regulator of claim 1 wherein the switching regulator is included in a battery charger.

3. The switching regulator of claim 1 wherein the controller includes an integrated circuit.

4. The switching regulator of claim 1 wherein the controller includes discrete electrical components.

5. A method, comprising:

measuring a feedback signal derived from an output of a power supply;

operating the power supply in an unregulated self protection auto-restart mode where the power supply operates at a reduced output voltage and reduced average output current if the feedback signal is less than a first threshold, wherein operating the power supply in an unregulated self protection auto-restart mode comprises continuously cycling between a first period of unregulated switching of the power supply and a second period of no switching of the power supply;

operating the power supply in an unregulated maximum power mode if the feedback signal is between the first threshold and a second threshold; and

operating the power supply in a regulated mode if the feedback signal is between the first threshold and a third threshold while greater than the second threshold.

6. The method of claim 5 further comprising operating the power supply in an unregulated inhibited switching mode if the feedback signal is greater than the third threshold.

7. The method of claim 5 wherein the first threshold is less than the third threshold.

8. The method of claim 7 wherein the second threshold is less than or equal to the third threshold.

9. The method of claim 6 wherein the output of the power supply is not regulated in response to the feedback signal when the power supply is operating in any one of the unregulated self protection auto-restart mode, the unregulated inhibited switching mode or the unregulated maximum power mode.