Power supply capable of AC and DC input utilizing winding of transformer as boost inductor

• US 7,254,048 B2
• Filed: 11/06/2006
• Issued: 08/07/2007
• Est. Priority Date: 06/20/2003
• Status: Expired due to Fees

• Current Assignee: Comarco Wireless Technologies Incorporated (Comarco Incorporated)
• Original Assignee: Comarco Wireless Technologies Incorporated (Comarco Incorporated)
• Inventors: Lanni, Thomas W
• Primary Examiner(s): Vu, Bao Q.
• Application Number:
  US11/593,244
• Publication Number:
  US 20070053211A1
• Time in Patent Office: 274 Days
• Field of Search: 363/142, 363/26, 363/24, 363/133, 363/134, 307/64, 307/66, 307/72, 307/73, 307/75
• US Class Current: 363/142
• CPC Class Codes: H02M 1/10 Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from ac or dc
• CPC Class Codes: H02M 3/33592 having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
• 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 programmable AC/DC power converter receives a plurality of input voltages and outputs a single voltage from an input voltage system. A transformer receives the single voltage. One of the plurality of input voltages is provided at a center tap of a secondary winding of the transformer. A transformed voltage is output. A rectifier receives the transformed voltage and outputs a DC voltage. A buck regulator receives a DC voltage, creates a regulated voltage, and outputs the regulated voltage and a regulated current to a portable appliance. A error correction system receives a programming signal and regulated signals and verifies that the regulated signal to programming signal ratio is within an acceptable range.

Claims

1. A method to output a regulated voltage from a power converter, comprising:

directly receiving a DC input voltage at a center tap of a secondary winding of the transformer, the transformer being coupled to a first switching device and also including a primary winding, the center tap of the transformer separating the secondary winding of the transformer into a first autowinding and a second autowinding;

charging a first capacitor to a first DC voltage corresponding to the DC input voltage by coupling the DC input voltage across the first capacitor;

charging a second capacitor to a second DC voltage corresponding to the DC input voltage by utilizing a control circuit and second switching devices to control the first autowinding and the second autowinding of the transformer to apply the second voltage across the second capacitor; and

adding at a first node, the first DC voltage and the second DC voltage to generate a third DC voltage, wherein the first switching device and the second switching devices are driven by signals operating at a common frequency.

2. The method of claim 1, further including receiving the third DC voltage at a buck regulator;

creating a regulated voltage at the buck regulator; and

outputting the regulated voltage as an output voltage.

3. The method of claim 2, further including receiving a programming signal at an error correction subsystem;

receiving regulated signals at the error correction subsystem, the regulated signals derived from the output voltage;

comparing the programming signal with one of the regulated signals to determine if a ratio of the one of the regulated signals to the programming signal is within an acceptable range; and

outputting a correction signal if the ratio of the one of the regulated signals to the programming signal is outside the acceptable range.

4. The method of claim 3, wherein the programming signal is a voltage programming signal and the one of the regulated signals is a regulated voltage.

5. The method of claim 3, wherein the programming signal is a current programming signal and the one of the regulated signals is a regulated current.

6. The method of claim 1, wherein the third DC voltage has a value approximately twice the value of the DC input voltage.

7. A power converter, comprising:

a transformer, said transformer having a primary winding and a secondary winding, the primary winding coupled to a first switching circuit and the secondary winding including a center tap to separate the secondary winding into a first autowinding and a second autowinding, the DC input voltage being connected to the center tap of the secondary winding of the transformer;

a first capacitor, coupled to the DC input voltage, which is charged to a first voltage corresponding to the DC input voltage; and

a control circuit coupled to a second switching circuit, the second switching circuit coupled to the secondary winding, wherein the control circuit and the second switching circuit control the first autowinding and the second autowinding to charge a second capacitor to a second DC voltage corresponding to the DC input voltage, wherein the first DC voltage and the second DC voltage are added together to create a third DC voltage, and the first switching circuit and the second switching circuit are driven by signals having a common frequency.

8. The power converter of claim 7, wherein an AC input voltage is input to the power converter simultaneously with the DC input voltage.

9. The power converter of claim 7, further including a buck regulator to receive the third DC voltage, generate a regulated voltage, and output the regulated voltage as an output voltage.

10. The power converter of claim 9, further including a voltage error system to receive a programming voltage and a value representative of the regulated voltage, and to output a voltage correction signal to the buck regulator based on a ratio between the programming voltage and the value representative of the regulated voltage.

11. The power converter of claim 9, further including an error correction system to receive a programming current and a value representative of the regulated current, and to output a correction signal to the buck regulator based on a ratio between the programming current and the value representative of the regulated current.

12. A power converter, comprising:

a transformer, coupled to a first switching circuit, said transformer having a primary winding and a secondary winding, the primary winding coupled to a first switching circuit and the secondary winding including a center tap to separate the secondary winding into a first autowinding and a second autowinding, the DC input voltage being directly applied to the center tap of the secondary winding of the transformer; and

a control circuit, coupled to a second switching circuit, the second switching circuit coupled to the secondary winding, wherein the control circuit and the second switching circuit control the first autowinding and the second autowinding to output a combined voltage, the combined voltage being an addition of a voltage across the first autowinding and a voltage across the second autowinding, wherein the first switching circuit and the second switching circuit operate at a common frequency.

13. The power converter of claim 12, further including a buck regulator to receive the combined voltage, to generate a regulated voltage, and to output the regulated voltage as an output voltage.

14. The power converter of claim 13, further including a voltage error system to receive a programming voltage and a value representative of the regulated voltage, and to output a voltage correction signal to the buck regulator based on a ratio between the programming voltage and the value representative of the regulated voltage.

15. The power converter of claim 13, further including an error correction system to receive a programming current and a value representative of a regulated current, and to output a correction signal to the buck regulator based on a ratio between the programming current and the value representative of the regulated current.

16. A method to output a regulated voltage from a power converter, comprising:

receiving a DC input voltage at a center tap of a secondary winding of a transformer, the transformer also having a primary winding coupled to a first switching circuit, the center tap of the secondary winding dividing the transformer into a first autowinding and a second autowinding;

driving a second switching circuit from a control circuit, the second switching circuit coupled to the secondary winding, wherein the control circuit and the second switching circuit control the first autowinding and second autowinding to output a combined voltage, the combined voltage being an addition of a voltage across the first autowinding and a voltage across the second autowinding, wherein the first switching circuit and the second switching circuit are driven to operate at a common frequency; and

outputting the combined voltage as a DC output voltage.

17. The method of claim 16, further including receiving the DC output voltage at a buck regulator;

creating a regulated voltage at the buck regulator; and

outputting the regulated voltage to an electronic device.

18. The method of claim 17, further including receiving a programming signal at an error correction system;

receiving regulated signals at the error correction system;

comparing the programming signal with one of the regulated signals to determine if a ration of the one of the regulated signals to the programming signal is within an acceptable range; and

outputting a correction signal if the ratio of the one of the regulated signals to the programming signal is outside the acceptable range.

19. The method of claim 18, wherein the programming signal is a voltage programming signal and the one of the regulated signals is a signal representative of the regulated voltage.

20. The method of claim 18, wherein the programming signal is a current programming signal and the one of the regulated signals is a regulated current.