System and method for providing DC power to an outside electrochromic mirror (OEC) using a pulse width modulated (PWM) input

• US 8,879,140 B2
• Filed: 05/10/2012
• Issued: 11/04/2014
• Est. Priority Date: 05/12/2011
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Nagel, Gregory J., Turnbull, Robert R.
• Primary Examiner(s): Harrington, Alicia M
• Assistant Examiner(s): RAKOWSKI, CARA E
• Application Number:
  US13/468,078
• Publication Number:
  US 20120287496A1
• Time in Patent Office: 908 Days
• Field of Search: 359265-275, 359/277, 359245-247, 359/242, 345/49, 345/105, 250/70, 348/814, 348/817, 438/929, 349182-186
• US Class Current: 359/267
• CPC Class Codes: G02F 1/163 Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor
• CPC Class Codes: H02M 7/217 using semiconductor devices only

Abstract

A power supply for supplying direct current (DC) power from a pulse width modulated (PWM) source includes a connector configured to be in electrical communication with a PWM power source. A hold-up circuit is in electrical communication with the connector and is configured to convert electrical power supplied from the PWM power source to DC power. This DC power is supplied to a drive circuit where a microcontroller is configured to control the drive circuit by supplying the DC power from the drive circuit to a load.

Claims

1. A system for supplying DC power derived from a pulse width modulated (PWM) source comprising:

a connector configured to be in electrical communication with a PWM power source;

at least one hold-up circuit in electrical communication with the connector, the at least one hold-up circuit comprising;

a first hold-up circuit configured to convert a PWM power supplied from the PWM power source to a first DC power and supply the first DC power to a microcontroller; and

a second hold-up circuit configured to convert the PWM power supplied from the PWM power source to a second DC power, and supply the second DC power to a drive circuit; and

wherein the microcontroller is configured to control the drive circuit by regulating a DC voltage from the drive circuit to a load, wherein the load is an electrochromic (EC) mirror element.

2. A system for supplying DC power as in claim 1, wherein the microcontroller is configured to control the DC voltage from the drive circuit based on the pulse width of the PWM power.

3. A system for supplying DC power as in claim 2, wherein the microcontroller is configured to control the DC voltage from the drive circuit based on stored reference data corresponding to the pulse width of the PWM power.

4. A system for supplying DC power as in claim 1, wherein the at least one hold-up circuit includes at least one capacitive device for storing the PWM power supplied by the PWM power source.

5. A system for supplying DC power as in claim 1, wherein the DC voltage supplied to the load is in a range from approximately 0 volts to 1.5 volts.

6. A system for supplying DC power as in claim 1, wherein the DC voltage supplied to the load is based upon light readings received at an interior electrochromic (IEC) mirror.

7. A system for supplying DC power as in claim 6, wherein the light readings are based upon both ambient light and glare light.

8. A system for supplying DC power as in claim 1, wherein the load is an outside electrochromic (EC) mirror element.

9. A vehicular power supply system for supplying DC power derived from a pulse width modulated (PWM) power source comprising:

a connector configured to be in electrical communication with a PWM power source provided by an on/off keying of a voltage source in a vehicle;

a first hold-up circuit for converting a PWM power from the PWM power source to a first DC power supplied to at least one microcontroller;

a second hold-up circuit for converting the PWM power to a second DC power supplied to a drive circuit; and

wherein the at least one microcontroller is configured to control the drive circuit by regulating a DC voltage from the drive circuit to an EC mirror based upon a pulse width of the PWM power.

10. A vehicular power supply system as in claim 9, wherein the first hold-up circuit and the second hold-up circuit include at least one capacitive device for storing power supplied by the PWM power source.

11. A vehicular power supply system as in claim 9, wherein the DC voltage supplied to the EC mirror is in a range from approximately 0 volts to 1.5 volts.

12. A vehicular power supply system as in claim 9, wherein the DC voltage supplied to the EC mirror is based upon light readings received at an interior electrochromic (IEC) mirror.

13. A vehicular power supply system as in claim 9, wherein the EC mirror is an outside EC (OEC) mirror mounted to a vehicle door.

14. A method for supplying DC power derived from a pulse width modulated (PWM) source comprising the steps of:

receiving PWM power from a PWM power source;

converting the PWM power to a first DC power;

supplying the first DC power to a microcontroller;

converting the PWM power to a second DC power;

supplying the second DC power to a drive circuit;

controlling the drive circuit for supplying a DC voltage to a load,

utilizing at least one capacitive device in at least one hold-up circuit for storing power supplied by the PWM power source,

utilizing at least one of the at least one hold-up circuits for converting the PWM power to the first DC power supplied to the microcontroller, and

utilizing an electrochromic EC mirror element as the load.

15. A method for supplying DC power as in claim 14, further comprising the step of:

utilizing the microcontroller for controlling the DC voltage from the drive circuit based on the pulse width of the PWM power.

16. A method for supplying DC power as in claim 14, further comprising the step of:

supplying the DC voltage to the load in a range between approximately 0 volts to 1.5 volts.

17. A method for supply DC power as in claim 14, wherein the load is an EC mirror, and the method further comprising the step of:

supplying the second DC power to the EC mirror based upon light readings received at an interior electrochromic (IEC) mirror.

18. A method for supplying DC power as in claim 14, further comprising the step of:

utilizing an outside electrochromic (OEC) mirror element as the load.