Power supply with a digital feedback loop

• US 7,324,354 B2
• Filed: 07/06/2006
• Issued: 01/29/2008
• Est. Priority Date: 07/08/2005
• Status: Active Grant

• Current Assignee: Bio-Rad Laboratories Incorporated
• Original Assignee: Bio-Rad Laboratories Incorporated
• Inventors: Joshi, Rahul, Hutson, Don
• Primary Examiner(s): STERRETT, JEFFREY L
• Application Number:
  US11/428,948
• Publication Number:
  US 20070008745A1
• Time in Patent Office: 572 Days
• Field of Search: 363/17, 363/61, 363/89, 363/95, 363/98
• US Class Current: 363/17
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 3/1588 comprising at least one synchronous rectifier element H02M3/1582, H02M3/1584 take precedence
• CPC Class Codes: H02M 3/33515 with digital control
• 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 wide range power supply capable of delivering 20V to 5000V is provided. The power supply of the present invention uses switch mode technology to achieve high overall operating efficiency and is capable of operating from no load to full load without loss of regulation. The power supply in accordance with the embodiments of the present invention operates directly from the utility supply (e.g., 110V/220V and 50 Hz/60 Hz). In one embodiment, the power supply'"'"'s power conversion stage includes the following stages: an input rectifier; a buck converter; a quasi-resonant inverter; and a voltage multiplier. The above indicated stages are connected in series to achieve the large output voltage range. High precision is obtained from a use of a digital feedback loop, possibly in connection with an analog feedback loop.

Claims

1. A wide range power supply device for protein electrophoresis, isoelectric focusing and electrophoretic blotting, comprising:

a power conversion stage, having

an input rectifier connected with a utility supply;

a dc/dc converter connected with the input rectifier;

a resonant inverter connected with the dc/dc converter;

a transformer connected with the resonant inverter; and

a voltage multiplier connected with the transformer and connected with an output voltage of the wide range power supply device;

a power supply controller operatively coupled with the dc/dc converter and the resonant inverter, wherein the power supply controller is coupled with the output voltage via one or more feedback loops; and

a supervisory controller operatively coupled with the power supply controller, wherein the coupling is accomplished with an optically isolated digital interface.

2. The wide range power supply device of claim 1, wherein the transformer has one secondary winding.

3. The wide range power supply device of claim 1, wherein the voltage output from the power supply varies from 20V to 5000V.

4. The wide range power supply device of claim 1, wherein the supervisory controller is part of one of the feedback loops.

5. The wide range power supply device of claim 4, wherein the supervisory controller sends a digital signal to the power supply controller, wherein the digital signal includes information as to an error in the output voltage.

6. The wide range power supply device of claim 5, wherein the information includes a new voltage setting for the power conversion stage.

7. The wide range power supply device of claim 1, further comprising an analog optocoupler, wherein the analog optocoupler is part of an analog feedback loop from the output voltage to the power supply controller.

8. The wide range power supply device of claim 1, wherein the dc/dc converter is a buck converter.

9. The wide range power supply device of claim 1, wherein the resonant inverter is a quasi-resonant inverter.

10. The wide range power supply device of claim 9, wherein the quasi resonant inverter is a half-bridge design.

11. The wide range power supply device of claim 1, wherein the voltage multiplier also acts as a rectifier of a signal from the transformer.

12. A method for controlling an output voltage of a switched-mode power supply, comprising:

receiving a first set point at a power supply controller, wherein a set point includes an output voltage setting;

generating the output voltage via control signals sent by the power supply controller to a power conversion stage, wherein an input of the power conversion stage is galvanically isolated from the output voltage;

measuring the output voltage with a supervisory controller;

calculating, with the supervisory controller, an error in the output voltage using the output voltage and a reference voltage,

transmitting a digital signal from the supervisory controller to the power supply controller based on the error, wherein the supervisory controller is galvanically isolated from the power supply controller; and

altering the control signals based on the digital signal.

13. The method of claim 12, further comprising:

receiving the first set point at a control board processor;

sending the first set point to the supervisory controller; and

digitally sending the first set point to the power supply controller.

14. The method of claim 12, wherein the control signals are PWM signals.

15. The method of claim 12, wherein the digital signal is transmitted through a digital optocoupler, wherein the digital optocoupler provides galvanic isolation between the power supply controller and supervisory controller.

16. The method of claim 12, further comprising:

transmitting, via an analog signal, the output voltage to the power supply controller;

using the analog signal in a feedback loop to alter the control signals to the power conversion stage.

17. The method of claim 16, wherein the digital signal includes a second set point.

18. The method of claim 16, wherein the analog signal is transmitted through a linear optocoupler, wherein the linear optocoupler provides galvanic isolation between the output of the power supply and the power supply controller.

19. A wide range power supply device, comprising:

a power conversion stage;

a power supply controller operatively coupled with the power conversion stage, wherein the power supply controller is coupled with an output voltage of the wide range power supply via one or more feedback loops; and

a supervisory controller operatively coupled with said control processor, wherein the coupling is accomplished with an optically isolated digital interface, wherein the supervisory controller is part of one of the feedback loops.

20. The wide range power supply device of claim 19, wherein the supervisory controller sends a digital signal to the power supply controller, wherein the digital signal includes information as to an error in the output voltage.

21. The wide range power supply device of claim 20, wherein the information includes a new voltage setting for the power conversion stage.