# US 9,517,715 B1 · Light driver arrangements for vehicle headlamps

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- Number: US 9,517,715 B1
- Document ID: US9517715B1
- Status: Granted
- Kind: B1
- Application number: 14/975,833
- Filed: 2015-12-20
- Granted: 2016-12-13
- Earliest claimed: 2015-12-20
- Assignees: Toyota Motor Engineering & Manufacturing North America, Inc.
- Applicants: Toyota Motor Engineering & Manufacturing North America, Inc.
- Inventors: Nicholas S. Sitarski
- Web page: https://patentgrep.com/patent/US9517715B1

## CPC

- B60Q 1/0076: {Switches therefor (B60Q1/1446, B60Q1/343, B60Q1/40 take precedence)}
- B60Q 1/04: the devices being headlights
- B60Q 1/1415: {Dimming circuits}
- B60Q 11/002: {Emergency driving lights in the event of failure of the principal lighting circuit}
- H05B 45/44: with an active control inside an LED matrix
- H05B 45/50: responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
- B60Q: ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL

## Abstract

A vehicle headlamp system can include a plurality of low beam light sources and a plurality of high beam light sources. In one or more arrangements, the light sources can be light emitting diodes. The system can include a first light driver operatively connected to selectively supply electrical energy to a first group of low beam light sources and/or a first group of high beam light sources. The system can include a second light driver operatively connected to selectively supply electrical energy to a second group of low beam light sources and/or a second group of high beam light sources. The system can further include a controller. The controller can be operatively connected to the first light driver and the second light driver to control the selective supply of electrical energy by the first light driver and the second light driver.

## Claims

### Claim 1

A vehicle lighting system comprising:
a plurality of low beam light sources including a first group of low beam light sources and a second group of low beam light sources;
a plurality of high beam light sources including a first group of high beam light sources and a second group of high beam light sources;
a first light driver operatively connected to the first group of low beam light sources and the first group of high beam light sources;
a second light driver operatively connected to the second group of low beam light sources and a second group of high beam light sources; and
a controller operatively connected to the first light driver and the second light driver, the controller being configured to:
cause the first light driver to selectively supply electrical energy to at least one of the first group of low beam light sources or the first group of high beam light sources, and
cause the second light driver to selectively supply electrical energy to at least one of the second group of low beam light sources or the second group of high beam light sources.

### Claim 2 (depends on 1)

The vehicle lighting system of claim 1, wherein the controller is further configured to operate the first light driver and the second light driver in a low beam operational mode, wherein, in the low beam operational mode:
the first light driver selectively supplies electrical energy to the first group of low beam light sources while bypassing the first group of high beam light sources, whereby the first group of low beam light sources are activated and the first group of high beam light sources are not activated, and
the second light driver selectively supplies electrical energy to the second group of low beam light sources while bypassing the second group of high beam light sources, whereby the second group of low beam light sources are activated and the second group of high beam light sources are not activated.

### Claim 3 (depends on 2)

The vehicle lighting system of claim 2, wherein the controller is further configured to operate the first light driver and the second light driver in a high beam operational mode, wherein, in the high beam operational mode:
the first light driver selectively supplies electrical energy to the first group of low beam light sources and the first group of high beam light sources in series, whereby the first group of low beam light sources are activated and the first group of high beam light sources are activated; and
the second light driver selectively supplies electrical energy to the second group of low beam light sources and the second group of high beam light sources in series, whereby the second group of low beam light sources are activated and the second group of high beam light sources are activated.

### Claim 4 (depends on 3)

The vehicle lighting system of claim 3, further including:
a first switching element operatively positioned between the first group of low beam light sources and the first group of high beam light sources; and
a second switching element operatively positioned between the second group of low beam light sources and the second group of high beam light sources,
wherein the controller is operatively connected to the first switching element and the second switching element,
wherein, in the low beam operational mode, the controller causes the first switching elements to be set to a position to allow electrical energy from the first light driver to be provided to the first group of low beam light sources while bypassing the first group of high beam light sources, and wherein the controller causes the second switching element to be set to a position to allow electrical energy from the second light driver to be provided to the second group of low beam light sources while bypassing the second group of high beam light sources.

### Claim 5 (depends on 4)

The vehicle lighting system of claim 4, wherein the first switching element is a transistor, and wherein the second switching element is a transistor.

### Claim 6 (depends on 1)

The vehicle lighting system of claim 1, wherein the plurality of low beam light sources are light emitting diodes, and wherein the plurality of high beam light sources are light emitting diodes.

### Claim 7 (depends on 1)

The vehicle lighting system of claim 1, wherein the first light driver is configured to supply electrical energy at an associated first power output, wherein the first group of low beam light sources has an associated power output, wherein the first group of high beam light sources has an associated power output, and wherein the first power output is greater than or equal to the sum of the power output by the first group of low beam light sources and the power output by the first group of high beam light sources, and
wherein the second light driver is configured to supply electrical energy at an associated second power output, wherein the second group of low beam light sources has an associated power output, wherein the second group of high beam light sources has an associated power output, and wherein the second power output is greater than or equal to the sum of the power output by the second group of low beam light sources and the power output by the second group of high beam light sources.

### Claim 8 (depends on 7)

The vehicle lighting system of claim 7, wherein the first power output is substantially equal to the second power output.

### Claim 9 (depends on 1)

The vehicle lighting system of claim 1, further including:
a light source fault sensor configured to detect a fault in one or more of the plurality of low beam light sources, wherein the light source fault sensor is operatively connected to the controller.

### Claim 10 (depends on 9)

The vehicle lighting system of claim 9, wherein the controller is further configured to:
responsive to detecting a fault with one or more of the plurality of low beam light sources, cause the first light driver to supply electrical energy to the first group of high beam light sources while bypassing the first group of low beam light sources, and cause the second light driver to supply electrical energy to the second group of high beam light sources while bypassing the second group of low beam light sources, whereby the plurality of high beam light sources are activated and the plurality of low beam light sources are not activated.

### Claim 11 (depends on 1)

The vehicle lighting system of claim 1, wherein at least the plurality of low beam light sources and the plurality of high beam light sources are provided in a single headlamp assembly.

### Claim 12

A vehicle headlamp system comprising:
a plurality of low beam LEDs;
a plurality of high beam LEDs;
the plurality of low beam LEDs and the plurality of high beam LEDs being a part of a light source for a single headlamp assembly;
a first light driver;
a second light driver; and
the first light driver and the second light driver being configured to selectively provide electrical energy to power the plurality of low beam LEDs and the plurality of high beam LEDs in a commingled manner.

### Claim 13 (depends on 12)

The vehicle headlamp system of claim 12, wherein the plurality of low beam LEDs includes a first group of low beam LEDs and a second group of low beam LEDs, wherein the plurality of high beam LEDs includes a first group of high beam LEDs and a second group of high beam LEDs, wherein the light source includes a low beam operational mode, and wherein, in the low beam operational mode:
the first light driver selectively provides electrical energy to the first group of low beam LEDs while bypassing the first group of high beam LEDs,
the second light driver selectively provides electrical energy to the second group of low beam LEDs while bypassing the second group of high beam LEDs,
whereby the plurality of low beam LEDs are activated and the plurality of high beam LEDs are not activated.

### Claim 14 (depends on 12)

The vehicle headlamp system of claim 12, wherein the plurality of low beam LEDs includes a first group of low beam LEDs and a second group of low beam LEDs, wherein the plurality of high beam LEDs includes a first group of high beam LEDs and a second group of high beam LEDs, wherein the light source includes a high beam operational mode, and wherein, in the high beam operational mode:
the first light driver selectively provides electrical energy to the first group of low beam LEDs and the first group of high beam LEDs,
the second light driver selectively provides electrical energy to the second group of low beam LEDs and the second group of high beam LEDs,
whereby the plurality of low beam LEDs are activated and the plurality of high beam LEDs are activated.

### Claim 15 (depends on 12)

The vehicle headlamp system of claim 12, wherein the plurality of low beam LEDs includes a first group of low beam LEDs and a second group of low beam LEDs, wherein the plurality of high beam LEDs includes a first group of high beam LEDs and a second group of high beam LEDs,
wherein the first light driver is configured to supply electrical energy at an associated first power output, wherein the first group of low beam LEDs has an associated power output, wherein the first group of high beam LEDs has an associated power output, and wherein the first power output is greater than or equal to the sum of the power output by the first group of low beam LEDs and the power output by the first group of high beam LEDs, and
wherein the second light driver is configured to supply electrical energy at an associated second power output, wherein the second group of low beam LEDs has an associated power output, wherein the second group of high beam LEDs has an associated power output, and wherein the second power output is greater than or equal to the sum of the power output by the second group of low beam LEDs and the power output by the second group of high beam LEDs.

### Claim 16 (depends on 12)

The vehicle headlamp system of claim 12, further including:
a light source fault sensor configured to detect a fault in one or more of the plurality of low beam LEDs; and
a controller operatively connector the light source fault sensor, wherein the controller is operatively connected to the first light driver and the second light driver.

### Claim 17 (depends on 16)

The vehicle headlamp system of claim 16, wherein the controller is further configured to:
responsive to detecting a fault with one or more of the plurality of low beam LEDs, cause, using the controller, the first light driver and the second light driver to supply electrical energy to the plurality of high beam LEDs while bypassing the low beam LEDs, whereby the plurality of high beam LEDs are activated and the plurality of low beam LEDs are not activated.

### Claim 18

A method of operating a vehicle headlamp system, the vehicle headlamp system including a plurality of low beam light sources and a plurality of high beam light sources, the method comprising:
receiving a signal to operate the vehicle headlamp system in one of a low beam operational mode or a high beam operational mode;
responsive to the received signal being a signal to operate the vehicle headlamp system in the low beam operational mode, causing, using a controller, a first light driver to supply electrical energy to a first group of low beam light sources while bypassing a first group of high beam light sources, and causing, using the controller, a second light driver to supply electrical energy to a second group of low beam light sources while bypassing a second group of high beam light sources, whereby the plurality of low beam light sources are activated and the plurality of high beam light sources are not activated; and
responsive to the signal being a signal to operate the vehicle headlamp system in the high beam operational mode, causing, using the controller, the first light driver to supply electrical energy to the first group of low beam light sources and the first group of high beam light sources in series, and causing, using the controller, the second light driver to supply electrical energy to the second group of low beam light sources and the second group of high beam light sources in series, whereby the plurality of low beam light sources are activated and the plurality of high beam light sources are activated.

### Claim 19 (depends on 18)

The method of claim 18, further including:
detecting whether there is a fault in one or more of the plurality of low beam light sources; and
responsive to detecting a fault with one or more of the plurality of low beam light sources, causing, using the controller, the first light driver to supply electrical energy to a first group of high beam light sources while bypassing a first group of low beam light sources, and causing, using a controller, the second light driver to supply electrical energy to a second group of high beam light sources while bypassing the second group of low beam light sources, whereby the plurality of high beam light sources are activated and the plurality of low beam light sources are not activated.

### Claim 20 (depends on 18)

The method of claim 18, wherein the first light driver supplies electrical energy at an associated first power output, wherein the first group of low beam light sources has an associated power output, wherein the first group of high beam light sources has an associated power output, and wherein the first power output is greater than or equal to the sum of the power output by the first group of low beam light sources and the power output by the first group of high beam light sources, and
wherein the second light driver supplies electrical energy at an associated second power output, wherein the second group of low beam light sources has an associated power output, wherein the second group of high beam light sources has an associated power output, and wherein the second power output is greater than or equal to the sum of the power output by the second group of low beam light sources and the power output by the second group of high beam light sources.