Power supply for electrochromic mirrors in high voltage automotive power systems

• US 6,958,844 B2
• Filed: 09/08/2003
• Issued: 10/25/2005
• Est. Priority Date: 10/22/1999
• Status: Expired due to Fees

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Bauer, Frederick T., Turnbull, Robert R.
• Primary Examiner(s): THOMPSON, TIMOTHY J
• Application Number:
  US10/657,625
• Publication Number:
  US 20040051378A1
• Time in Patent Office: 778 Days
• Field of Search: 359/265, 359/271, 359/273, 359/608, 359/275, 359/269, 359/267, 359/601, 348/148, 340/461, 340/433, 340/438, 340/457
• US Class Current: 359/265
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors

Abstract

A rearview mirror assembly is disclosed including a housing adapted to be mounted to the vehicle, a mirror disposed in the housing, at least one electrically powered device disposed in the housing, and a power supply for receiving power from a vehicle power source having a voltage in excess of about 24 V and for supplying power at a voltage of about 5 V or less to the electrically powered device. The electrically powered device and the power supply exhibit an electromagnetic interference level of less than about 41 dBμV/m for emissions in the frequency range from about 0.4 MHz to about 20 MHz. The mirror is preferably an electrochromic mirror, and the electrically powered device may be a control circuit for the electrochromic mirror.

Claims

1. A vehicular electrical system, comprising:

at least one electrically operated rearview mirror element;

a power supply configured to receive power from a vehicle power source having a first voltage, said power supply is further configured to supply power to said at least one electrically operated rearview mirror element and at least one electrically powered device at a second voltage less than said first voltage, the vehicular electrical system exhibiting an electromagnetic interference level less than about 47.8 dBμ

V/m for emissions in the frequency range from about 0.4 MHz to about 1000 MHz; and

said at least one electrically powered device is selected from the group comprising;

a light-emitting diode, a break light, a center high-mounted stop lamp, a cargo light, a turn signal indicator assembly, a cellular telephone transceiver, a trainable transceiver, a user activated switch, a tire pressure monitoring system, a GPS receiver, a compass, a display, a vehicle bus interface and a light sensor.

2. A vehicular electrical system as in claim 1 wherein said electromagnetic interference level is less than about 28 dBμ

V/m for narrowband emissions in the AM broadcast band.

3. A vehicular electrical system as in claim 1 wherein said electromagnetic interference level is less than about 28 dBμ

V/m for emissions in the frequency range from about 119.132 MHz to about 375 MHz.

4. A vehicular electrical system as in claim 1 wherein said first voltage is greater than about 24 volts.

5. A vehicular electrical system as in claim 1 wherein said second voltage is less than about 5 volts.

6. A vehicular electrical system as in claim 1 wherein said at least one electrically powered device is configured as a remote keyless entry system.

7. A vehicular electrical system as in claim 1 wherein said trainable transceiver is configured to function as a garage door opener.

8. A vehicular electrical system as in claim 1 wherein said cellular telephone transceiver is part of a vehicle communication system.

9. A vehicular electrical system, comprising:

a power supply configured to receive power from a vehicle power source having a voltage in excess of about 24 volts, said power supply is further configured to supply power to at least one electrically operated rearview mirror element and at least one electrically powered device at a voltage less than said power source voltage, said electrical system exhibiting an electromagnetic interference level less than about 47.8 dBμ

V/m for emissions in the frequency range from about 0.4 MHz to about 1000 MHz, wherein said at least one electrically powered device is selected from the group comprising;

a light-emitting diode, a break light, a center high-mounted stop lamp, a cargo light, a turn signal indicator assembly, a cellular telephone transceiver, a trainable transceiver, a user activated switch, a tire pressure monitoring system, a GPS receiver, a compass, a display, a vehicle bus interface and a light sensor.

10. A vehicular electrical system as in claim 9 wherein said electromagnetic interference level is less than about 28 dBμ

V/m for narrowband emissions in the AM broadcast band.

11. A vehicular electrical system as in claim 9 wherein said electromagnetic interference level is less than about 28 dBμ

V/m for emissions in the frequency range from about 119.132 MHz to about 375 MHz.

12. A vehicular electrical system as in claim 9 wherein said second voltage is less than about 5 volts.

13. A vehicular electrical system as in claim 9 wherein said trainable transceiver is configured to function as a garage door opener.

14. A vehicular electrical system as in claim 9 wherein said at least one electrically powered device is configured as a remote keyless entry system.

15. A vehicular electrical system as in claim 9 wherein said cellular telephone transceiver is part of a vehicle communication system.

16. A vehicular electrical system, comprising:

a power supply configured to receive power from a vehicle power source having a voltage in excess of about 24 volts, said power supply is further configured to supply power to at least one electrically operated rearview mirror element and at least one electrically powered device at a voltage less than said power source voltage, said electrical system exhibiting an electromagnetic interference level less than about 28 dBμ

V/m for narrowband emissions in the AM broadcast band.

17. A vehicular electrical system as in claim 16 wherein said at least one electrically powered device is selected from the group comprising:

a light-emitting diode, a break light, a center high-mounted stop lamp, a cargo light, a turn signal indicator assembly, a cellular telephone transceiver, a trainable transceiver, a user activated switch, a tire pressure monitoring system, a GPS receiver, a compass, a display, a vehicle bus interface and a light sensor.

18. A vehicular electrical system as in claim 17 wherein said trainable transceiver is configured to function as a garage door opener.

19. A vehicular electrical system as in claim 16 wherein said at least one electrically powered device is configured as a remote keyless entry system.

20. A vehicular electrical system as in claim 17 wherein said cellular telephone transceiver is part of a vehicle communication system.

21. A vehicular electrical system, comprising:

a power supply configured to receive power from a vehicle power source having a voltage, said power supply is further configured to supply power to at least one electrically powered device at a voltage less than said power source voltage, said electrical system exhibiting an electromagnetic interference level less than about 47.8 dBμ

V/m for emissions in the frequency range from about 0.4 MHz to about 1000 MHz; and

circuitry for dithering the pulse width or the switching frequency of said power supply.

22. A vehicular electrical system as in claim 21 wherein said at least one electrically powered device is selected from the group comprising:

a light-emitting diode, a break light, a center high-mounted stop lamp, a cargo light, a turn signal indicator assembly, a cellular telephone transceiver, a trainable transceiver, an electrochromic mirror, a user activated switch, a tire pressure monitoring system, a GPS receiver, a compass, a display, a vehicle bus interface and a light sensor.

23. A vehicular electrical system as in claim 21 wherein said electromagnetic interference level is less than about 28 dBμ

V/m for narrowband emissions in the AM broadcast band.

24. A vehicular electrical system as in claim 21 wherein said electromagnetic interference level is less than about 28 dBμ

V/m for narrowband emissions in the AM broadcast band.

25. A vehicular electrical system as in claim 22 wherein said trainable transceiver is configured to function as a garage door opener.

26. A vehicular electrical system as in claim 21 wherein said electrically powered device is configured as a remote keyless entry system.

27. A vehicular electrical system as in claim 22 wherein said cellular telephone transceiver is part of a vehicle communication system.

28. A vehicular electrical system as in claim 21 wherein said first voltage is greater than about 24 volts.

29. A vehicular electrical system as in claim 21 wherein said second voltage is less than about 5 volts.