Universal DC power

• US 20060226712A1
• Filed: 04/06/2005
• Published: 10/12/2006
• Est. Priority Date: 04/06/2005
• Status: Active Grant

• Current Assignee: James G. Eldredge
• Original Assignee: Flexsil, Inc.
• Inventors: Eldredge, James G.
• Granted Patent: US 7,466,042 B2
• Time in Patent Office: Days
• US Class Current: 307/154
• CPC Class Codes: H02M 3/157 with digital control

Abstract

A power converter capable of providing a range of DC voltages to an external device and a method of providing a range of DC power are provided. The power converter comprises a supply circuit for receiving a request for DC power and for providing the requested DC power. The supply circuit comprises a detection circuit for sensing a connection to an external device, a source controller circuit for determining a DC output power required by the external device, and a converter circuit for generating the required DC output power. The external device comprises a device controller circuit for communicating the request for DC power. A first conductor provides a path for the device to communicate the required DC power to the power converter and for the power converter to supply the required DC power. A second conductor provides a common reference for conducting return current to the power converter.

Claims

1. A power converter capable of providing a range of DC power, comprising:

a supply circuit for receiving a request for DC power from at least one external device and for providing the requested DC power to the at least one external device.

2. The power converter of claim 1, further comprising:

an input circuit for receiving an input voltage and generating a DC input voltage.

3. The power converter of claim 2, wherein the input circuit receives an AC voltage.

4. The power converter of claim 2, wherein the input circuit receives a DC voltage.

5. The power converter of claim 2, wherein the supply circuit comprises:

a detection circuit for sensing a connection to an external device;

a source controller circuit for determining a DC output power required by the external device;

a converter circuit for generating the required DC output power from the generated DC input voltage; and

first and second conductors for connecting the power converter to the external device, wherein the first conductor provides a path for the external device to communicate the required DC output power to the power converter and for the power converter to supply the required DC output power to the external device, and the second conductor provides a common reference for conducting return current to the power converter.

6. The power converter of claim 5, wherein the converter circuit is configurable as a current source.

7. The power converter of claim 2, wherein the supply circuit comprises:

a plurality of detection circuits for sensing connections to a plurality of external devices;

a source controller circuit for determining a plurality of DC output power required by the plurality of external devices;

a plurality of converter circuits for generating the plurality of required DC output power from the generated DC input voltage; and

a plurality of first and second conductor pairs for connecting the power converter to the plurality of external devices, wherein the first conductor provides a path for one of the plurality of external devices to communicate its required DC output power to the power converter and for the power converter to supply the required DC output power to one of the plurality of external devices, and the second conductor provides a common reference for conducting return current to the power converter.

8. The power converter of claim 1, wherein the external device comprises:

a device controller circuit for communicating a request for DC power, and first and second conductors for connecting the external device to the power converter, wherein the first conductor provides a path for the external device to communicate the required DC output power to the power converter and for the power converter to supply the required DC output voltage to the external device, and the second conductor provides a common reference for conducting return current to the power converter.

9. The power converter of claim 2, wherein the input voltage is received from a second power converter, further comprising:

a device controller circuit for communicating a request for DC power, and

first and second conductors for connecting the power converter to a second power converter, wherein the first conductor provides a path for the power converter to communicate the required DC output power to the second power converter and for the second power converter to supply the required DC output voltage to the power converter, and the second conductor provides a common reference for conducting return current to the second power converter.

10. The power converter of claim 1, wherein the power converter is implemented in a semiconductor device.

11. A DC-powered device requiring DC power, comprising:

a device controller circuit for communicating a request for DC power; and

first and second conductors for connecting the DC-powered device to a power converter, wherein the first conductor provides a path for the DC-powered device to communicate the required DC output power to the power converter and for the power converter to supply the required DC output power to the DC-powered device, and the second conductor provides a common reference for conducting return current to the power converter.

12. The DC-powered device of claim 11, wherein the device controller circuit comprises:

a first circuit for establishing as DC output voltage required by the DC-powered device; and

a second circuit for establishing a maximum average current required by the DC-powered device.

13. The DC-powered device of claim 12, wherein the first circuit comprises a zener diode and a first transistor connected in series between the first and second conductors.

14. The DC-powered device of claim 12, wherein the first circuit comprises a resistor connected between the first and second conductors.

15. The DC-powered device of claim 12, wherein the second circuit comprises a capacitor connected between the first and second conductors.

16. The DC-powered device of claim 12, wherein the device controller circuit further comprises:

a switching circuit for detecting the DC output power supplied by the power converter and providing the supplied DC output power to the DC-powered device.

17. The DC-powered device of claim 12, wherein the device controller circuit further comprises:

a loading circuit coupled to the first and second conductors for providing a disconnect signal to the power converter.

18. The DC-powered device of claim 17, wherein the loading circuit comprises a resistor and a transistor connected in series between the first and second conductors.

19. The DC-powered device of claim 11, wherein the device controller circuit comprises:

a first circuit for signaling the presence of the DC-powered device to the power converter;

a communications circuit for forming a communications packet indicating select electrical parameters of the required DC output power;

a switching circuit for detecting the DC output power supplied by the power converter and providing the supplied DC output power to the DC-powered device; and

a loading circuit coupled to the first and second conductors for providing a disconnect signal to the power converter.

20. The DC-powered device of claim 19, wherein the first circuit comprises a first resistor and a first transistor connected in series between the first and second conductors.

21. The DC-powered device of claim 19, further comprising:

a power supply circuit having an input coupled to the first conductor and an output coupled to the device controller circuit, wherein the output remains steady for short periods of time when power to the input is removed.

22. The DC-powered device of claim 11, wherein the DC-powered device is implemented in a semiconductor device.

23. A method of providing a range of DC power, comprising:

receiving a request for DC power from at least one external device; and

providing the requested DC power to the at least one external device.

24. The method of claim 23, further comprising:

generating a DC input voltage from a received input voltage;

detecting a connection between at least one external device and a power converter;

determining the DC output power required by the at least one external device;

generating the required DC output power from the DC input voltage; and

supplying the required DC output power to the at least one external device.

25. The method of claim 24, wherein detecting the connection between the at least one external device and the power converter comprises:

sampling a voltage level at a first conductor connecting the external device to the power converter.

26. The method of claim 23, wherein the at least one external device communicates with the power converter using a communications protocol selected from a plurality of communications protocols.

27. The method of claim 26, wherein the plurality of communications protocol comprises a simple protocol and a complex protocol.

28. The method of claim 27, further comprising:

determining the communications protocol used by the at least one external device.

29. The method of claim 28, wherein determining the communications protocol used by the at least one external device comprises measuring a capacitive load on the first conductor connecting the at least one external device to the power converter.

30. The method of claim 28 wherein, if the at least one external device is determined to be using the simple protocol, determining the required DC output power, comprises:

determining a maximum average current required by the at least one external device; and

repeatedly sampling a voltage level at a first conductor connecting the at least one external device to the power converter until a steady value of the sampled voltage level is measured.

31. The method of claim 28 wherein, if the at least one external device is determined to be using the complex protocol, determining the required DC output power comprises:

receiving a communications packet formed by the at least one external device, the packet indicating select electrical parameters of the required DC output power.

32. The method of claim 31, wherein the electrical parameters of the DC output power comprise:

a DC output voltage;

a maximum average current;

a maximum peak current; and

a slew rate of DC output voltage turn-on ramp.

33. The method of claim 32, wherein the communications packet further comprises a parameter for signaling that the at least one external device is a battery requiring a recharge operation.

34. The method of claim 33, wherein generating and supplying the required DC output power in the battery recharge operation comprises:

configuring a converter circuit into a current source;

generating a current, the current value defined by the communications packet;

charging the battery with the generated current until the voltage level at the first conductor reaches the DC voltage value defined by the communications packet; and

entering a final charging phase.

35. The method of claim 34, wherein the final charging phase is a constant voltage phase comprising:

configuring the converter circuit as a voltage source;

generating a DC voltage, the voltage value defined by the communications packet; and

charging the battery with the generated DC voltage until the voltage level on the first conductor reaches the voltage value defined by the communications packet or until the battery is disconnected.

36. The method of claim 34, wherein the final charging phase is a fast charge phase comprising:

applying the required current for a predetermined time to the first conductor;

disabling the converter circuit configured as a current source; and

charging the battery until the voltage level on the first conductor reaches the voltage value defined by the communications packet or until the battery is disconnected.

37. A system for providing a range of DC power, comprising:

means for communicating a request for DC power from at least one external device; and

means for providing the requested DC power to the at least one external device.

38. The system of claim 37, further comprising:

means for receiving an input voltage and generating a DC input voltage;

means for detecting a connection to the at least one external device;

means for determining a DC output voltage required by the at least one external device;

means for generating the required DC output voltage from the generated DC input voltage.

39. The system of claim 37, wherein the means for communicating a request for DC power comprises a communications protocol selected from a plurality of communications protocols.

40. The system of claim 37, wherein the means for communicating a request for DC power comprises:

means for establishing a DC output voltage required by the at least one external device;

means for establishing the maximum average current required by the at least one external device.

41. The system of claim 37, wherein the means for communicating a request for DC power comprises:

means for forming communications packets indicating select electrical parameters of the requested DC power.

42. The system of claim 41, wherein the electrical parameters of the requested DC power comprise:

a DC output voltage;

a maximum average current;

a maximum peak current;

a slew rate of DC output voltage turn-on ramp;

a battery charge current; and

a battery fast charge time.