Driving several light sources

Patent metadata

Field	Value
Publication number	US-10321533-B2
Application number	US-201715691526-A
Country	US
Kind code	B2
Filing date	Aug 30, 2017
Priority date	May 21, 2015
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

A device for driving several light sources is provided, wherein the several light sources are arranged in a matrix structure; wherein the several light sources of the matrix structure are connected to a semiconductor device; wherein a portion of the semiconductor device corresponds to a light source of the matrix structure, wherein the portion of the semiconductor device comprises a diagnosis function which when activated is arranged for supplying an output diagnosis signal.

First claim

The invention claimed is:

1. A device for driving a plurality of LEDs (Light Emitting Diodes), comprising:
a semiconductor device comprising a plurality of portions,
wherein each portion of the plurality of portions corresponds to an LED of the plurality of LEDs,
wherein each portion of the plurality of portions comprises a pixel addressing block and each pixel addressing block comprises a memory unit, and
wherein a first portion of the plurality of portions of the semiconductor device further comprises a diagnosis function that when activated is arranged for supplying an output diagnosis signal; and

a single chip mounted on the semiconductor device,
wherein the plurality of LEDs is arranged in a matrix structure on the single chip and are connected to the semiconductor device.

2. The device according to claim 1 , wherein the diagnosis function is activated via a diagnosis signal applied to at least the first portion of the semiconductor device.

3. The device according to claim 2 , wherein the diagnosis signal is applied to a multiplexer to switch between the diagnosis function and a normal function of operation.

4. The device according to claim 1 , further comprising a comparator that is arranged for determining the output diagnosis signal as:
the output diagnosis signal has a first value in case a voltage for driving the LED is below a predetermined first threshold or above a predetermined second threshold;
the output diagnosis signal has a second value in case the voltage for driving the LED is not below the predetermined first threshold or not above a predetermined second threshold.

5. The device according to claim 1 , wherein the output diagnosis signal is provided at an output of the portion of the semiconductor device for driving the LED of the plurality of LEDs arranged in the matrix structure.

6. The device according to claim 1 , wherein each portion of the plurality of portions of the semiconductor device comprises the diagnosis function.

7. The device according to claim 1 , further comprising:
a shift register comprising at least two cells, wherein an output of each cell of the shift register controls one of the LEDs;
wherein the at least two cells are connected in series and are driven by a clock signal;
wherein each cell of the shift register comprises a flip-flop and a register;
wherein the output of the flip-flop is connected with the input of the register;
wherein the register is arranged to store the output of the register based on an update signal and wherein the output of the register controls one of the LEDs;
wherein the flip-flops of the at least two cells are filled with a data signal based on the clock signal;
wherein after a predetermined number of cycles of the clock signal, the update signal is conveyed to the registers driving the LEDs according to the values stored in the flip-flops of the cells; and
wherein the output diagnosis signal is stored in at least one cell of the shift register when the diagnosis function is activated.

8. The device according to claim 7 , wherein the flip-flop is a D-flip-flop and the register is an additional D-flip-flop, wherein the update signal is conveyed to the clock terminal of the additional D-flip-flop.

9. The device according to claim 7 , wherein the matrix structure comprises at least two rows and at least two columns.

10. The device according to claim 9 , wherein the register of the shift registers is associated with each LED of the matrix structure.

11. The device according to claim 9 , wherein the cells of the shift register are part of the semiconductor device, on top of which the matrix structure comprising the LEDs is arranged.

12. The device according to claim 11 , wherein the semiconductor device comprises a driver for each LED of the matrix structure.

13. The device according to claim 12 , wherein the driver for each LED of the matrix structure comprises a current mirror that is supplied with at least one reference current.

14. The device according to claim 13 , wherein the at least one reference current is generated at a common area of the semiconductor device and supplied to all drivers for the LEDs of the matrix structure.

15. The device according to claim 12 , wherein the at least two cells of the shift register and the driver associated with a single LED of the matrix structure are arranged on a surface area having a size that corresponds to the size of the surface area of the single LED of the matrix structure.

16. The device according to claim 11 , wherein the semiconductor device comprises a common circuitry for the LEDs of the matrix structure.

17. The device according to claim 16 , wherein the common circuitry is arranged in an area adjacent to the shift register.

18. The device according to claim 7 , further comprising a printed circuit board, wherein the semiconductor device is mounted on the printed circuit board.

19. The device according to claim 1 , wherein the memory unit comprises a shift register.

Assignees

• Infineon Technologies Ag

Inventors

• Scenini Andrea
• Capodivacca Giovanni
• De Cicco Adolfo

Classifications

• G09G3/32 Primary

  semiconductive, e.g. using light-emitting diodes [LED] · CPC title

• H05B33/0842

  Electricity · mapped topic

• H05B33/0857 Primary

  Electricity · mapped topic

• H05B45/397 Primary

  Current mirror circuits · CPC title

• Y02B20/30

  Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED] · CPC title