Interface Circuits for USB and Lighting Applications

• US 20150249393A1
• Filed: 03/03/2014
• Published: 09/03/2015
• Est. Priority Date: 03/03/2014
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Thian, Yaw Hann, Zhang, Di
• Granted Patent: US 9,853,553 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop

Abstract

In accordance with an embodiment of the present invention, a method of operating a power supply circuit includes receiving an input signal comprising a request for a target power supply voltage and/or current at an interface circuit at a secondary side of an adjustable power supply. The input signal is converted into a digital signal comprising the target power supply voltage and/or current. The digital signal is transmitted via a galavanically isolated signal path to a controller in a primary side of the adjustable power supply.

Claims

1. A method of operating a power supply circuit, the method comprising:

receiving an input signal comprising a request for a target power supply voltage and/or current at an interface circuit at a secondary side of an adjustable power supply;

converting the input signal into a digital signal comprising the target power supply voltage and/or current; and

transmitting the digital signal via a galavanically isolated signal path to a controller in a primary side of the adjustable power supply.

2. The method of claim 1, wherein the controller is configured to adjust the adjustable power supply to provide the requested target power supply voltage and/or current.

3. The method of claim 1, wherein the digital signal is a universal asynchronous receiver/transmitter (UART) data signal.

4. The method of claim 1, wherein input signal comprises differential data signals.

5. The method of claim 1, wherein input signal comprises data signals from a Universal Serial Bus (USB) data line.

6. The method of claim 1, wherein input signal comprises data signals from a Universal Serial Bus (USB) data line or an analog signal from a dimmer, wherein the digital signal is a universal asynchronous receiver/transmitter (UART) data signal.

7. The method of claim 1, wherein converting the input signal into a digital signal comprises:

using a table look up generator to generate a requested output voltage; and

generating a universal asynchronous receiver/transmitter (UART) data signal from the requested output voltage.

8. The method of claim 1, wherein converting the input signal into a digital signal comprises:

using an analog to digital converter to generate a digital signal comprising the request for the target power supply voltage and/or current; and

generating a universal asynchronous receiver/transmitter (UART) data signal from the digital signal comprising the request for the target power supply voltage and/or current.

9. The method of claim 1, wherein converting the input signal into a digital signal comprises:

determining an error between the target power supply voltage and/or current and the actual output from the adjustable power supply; and

generating a UART data signal from the determined error.

15. The interface circuit of claim 1, wherein input signal comprises data signals from a Universal Serial Bus (USB) data line or an analog signal from a dimmer, wherein the digital signal is a universal asynchronous receiver/transmitter (UART) data signal.

10. An interface circuit comprising:

a receiver circuit, the receiver circuit configured to receive an input signal at a secondary side of an adjustable power supply, the input signal comprising a request for a target power supply voltage and/or current;

a converter circuit configured to convert the input signal into a digital signal comprising the target power supply voltage and/or current; and

a transmitter circuit configured to be coupled to, but galvanically isolated from, a controller in a primary side of the adjustable power supply and configured to output the digital signal to the controller.

11. The interface circuit of claim 10, wherein the controller is configured to adjust the adjustable power supply to provide the requested target power supply voltage and/or current.

12. The interface circuit of claim 10, wherein the digital signal is a universal asynchronous receiver/transmitter (UART) data signal.

13. The interface circuit of claim 10, wherein input signal comprises differential data signals.

14. The interface circuit of claim 10, wherein input signal comprises data signals from a Universal Serial Bus (USB) data line.

16. The interface circuit of claim 10, wherein the converter circuit comprises:

a table look up generator configured to generate a requested output voltage; and

a universal asynchronous receiver/transmitter (UART) configured to generate a UART data signal from the requested output voltage.

17. The interface circuit of claim 10, wherein the converter circuit comprises:

an analog to digital converter configured to generate a digital signal comprising the request for the target power supply voltage and/or current; and

a universal asynchronous receiver/transmitter (UART) configured to generate a UART data signal from the digital signal comprising the request for the target power supply voltage and/or current.

18. The interface circuit of claim 10, wherein the converter circuit comprises:

an error amplifier configured to determine an error between the target power supply voltage and/or current and the actual output from the adjustable power supply; and

a universal asynchronous receiver/transmitter (UART) configured to generate a UART data signal from the determined error.

19. A power supply circuit comprising:

an adjustable power supply comprising a primary side winding and a secondary side winding;

an interface circuit coupled to the secondary side winding, the interface circuit comprising

a receiver circuit, the receiver circuit configured to receive an input signal at the secondary side, the input signal comprising a request for a target power supply voltage and/or current,

a converter circuit configured to convert the input signal into a digital signal comprising the target power supply voltage and/or current, and

a transmitter circuit configured to output the digital signal;

an optical or inductive coupler coupled to the interface circuit; and

a primary side circuit coupled to the primary side winding of the adjustable power supply, the primary side circuit configured to regulate the output of the adjustable power supply, the primary side circuit comprising a controller coupled to the optical or inductive coupler, wherein the controller is configured to

receive the digital signal from the interface circuit through the optical or inductive coupler, and

adjust the adjustable power supply to provide the requested target power supply voltage and/or current.

20. The power supply circuit of claim 19, wherein the converter circuit comprises:

a table look up generator configured to generate a requested output voltage;

an analog to digital converter configured to generate a digital signal comprising the request for the target power supply voltage and/or current; and

a universal asynchronous receiver/transmitter (UART) configured to generate a UART data signal from the requested output voltage and the request for the target power supply voltage and/or current.