Light emitting element drive apparatus and portable apparatus using same

Patent metadata

Field	Value
Publication number	US-8941581-B2
Application number	US-201314086570-A
Country	US
Kind code	B2
Filing date	Nov 21, 2013
Priority date	May 31, 2002
Publication date	Jan 27, 2015
Grant date	Jan 27, 2015

Abstract

A light emitting element drive apparatus capable of outputting the lowest voltage satisfying drive conditions and having high light emitting efficiency and low power loss, and a portable apparatus using the same, comprising an LED drive apparatus to which LEDs of different drive voltages required for emitting light are connected in parallel and driving one or more LEDs, wherein the LED drive apparatus 10 has drive circuits connected to the corresponding LEDs among a plurality of LEDs and driving the corresponding LEDs with luminances based on set values and power supply circuits for deciding a drive voltage value required for the highest light emission among one or more LEDs driven to emit light based on drive states of drive circuits (for example terminal voltages of the current source) and supplying a drive voltage having at least the decided value to LEDs in parallel.

First claim

What is claimed:

1. A processor comprising:
a first interface configured to control an operation of a first display device; and
a second interface configured to provide a first control signal to a first power supply device,
wherein the first power supply device comprises a first drive circuit configured to drive a first light emitting element corresponding to the first display device based on the first control signal, a first decision circuit configured to decide whether a first drive voltage of the first drive circuit is smaller than a first reference voltage, and a first power supply control circuit configured to boost a first supply voltage for the first light emitting element when the first decision circuit indicates that the first drive voltage is smaller than the first reference voltage.

2. The processor according to claim 1 , wherein the processor is configured to provide a command signal indicating whether the first light emitting element corresponding to the first display device should perform a normal on operation or a flashing operation.

3. The processor according to claim 1 , wherein the processor is configured to provide a synchronization signal.

4. The processor according to claim 1 , further comprising:
a third interface configured to control an operation of a second display device, wherein a second control signal is provided to a second power supply device, and the second power supply device comprises a second drive circuit configured to drive a second light emitting element corresponding to the second display device based on the second control signal, a second decision circuit configured to decide whether a second drive voltage of the second drive circuit is smaller than a second reference voltage, and a second power supply control circuit configured to boost a second supply voltage for the second light emitting element when the second decision circuit indicates that the second drive voltage is smaller than the second reference voltage.

5. The processor according to claim 4 , wherein the first display device is a main display of a portable apparatus, and the second display device is a sub-display of the portable apparatus.

6. The processor according to claim 5 , wherein the processor is configured to provide a command signal indicating whether the second display device should perform a normal on operation or a flashing operation.

7. The processor according to claim 6 , wherein the processor is configured to provide a synchronization signal.

8. A processing system, the system comprising:
a processing unit including a first interface and a second interface, the first interface being configured to control an operation of a first display device, and the second interface being configured to provide a first control signal; and
a first power supply device, configured to receive the first control signal from the processing unit, the first power supply device comprising a first drive circuit configured to drive a first light emitting element corresponding to the first display device based on the first control signal, a first decision circuit configured to decide whether a first drive voltage of the first drive circuit is smaller than a first reference voltage, and a first power supply control circuit configured to boost a first supply voltage for the first light emitting element when the first decision circuit indicates that the first drive voltage is smaller than the first reference voltage.

9. The processing system according to claim 8 , wherein the processing unit is configured to provide a command signal indicating whether the first light emitting element corresponding to the first display device should perform a normal on operation or a flashing operation.

10. The processing system according to claim 8 , wherein the processing unit is configured to provide a synchronization signal.

11. The processing system according to claim 8 , further comprising:
a second power supply device configured to receive a second control signal from the processing unit, the second power supply device comprising a second drive circuit configured to drive a second light emitting element corresponding to a second display device based on the second control signal, a second decision circuit configured to decide whether a second drive voltage of the second drive circuit is smaller than a second reference voltage, and a second power supply control circuit configured to boost a second supply voltage for the second light emitting element when the second decision circuit indicates that the second drive voltage is smaller than the second reference voltage.

12. The processing system according to claim 11 , wherein the first display device is a main display of a portable apparatus, and the second display device is a sub-display of the portable apparatus.

13. The processing system according to claim 12 , wherein the processing unit is configured to provide a command signal indicating whether the second display device should perform a normal on operation or a flashing operation.

14. The processing system according to claim 13 , wherein the processing unit is configured to provide a synchronization signal.

15. A method of providing supply voltages to light emitting elements of display devices, the method comprising:
receiving, by a first power supply device, a first control signal, the first power supply device comprising a first drive circuit configured to drive a first light emitting element corresponding to a first display device based on the control signal;
determining, by a first decision circuit of the first power supply device, whether a first drive voltage of the first drive circuit is smaller than a first reference voltage; and
boosting, by a first power supply control circuit of the first power supply device, a first supply voltage for the first light emitting element when the first decision circuit indicates that the first drive voltage is smaller than the first reference voltage.

16. The method according to claim 15 , further comprising:
receiving a command signal indicating whether the first light emitting element corresponding to the first display device should perform a normal on operation or a flashing operation.

17. The method according to claim 15 , further comprising:
receiving a synchronization signal.

18. The method according to claim 15 , further comprising:
receiving, by a second power supply device, the second power supply device comprising a second drive circuit configured to drive a second light emitting element corresponding to a second display device based on the second control signal;
determining, by a second decision circuit of the second power supply device, whether a second drive voltage of the second drive circuit is smaller than a second reference voltage; and
boosting, by a second power supply control circuit of the second power supply device, a second supply voltage for the second light emitting element when the second decision circuit indicates that the second drive voltage is smaller than the second reference voltage.

19. The method according to claim 18 , wherein the first display device is a main display of a portable apparatus, and the second display device is a sub-display of the portable apparatus.

20. The method according to claim 19 , wherein the processing unit is configured to provide a command signal indicating whether the second display device should perform a normal on operation or a flashing operation.

Assignees

• Sony Corp
• Sony Mobile Comm Inc

Inventors

• Tsuchida Kazuhito
• Saito Junji
• Sudo Kazuo

Classifications

• H05B45/46

  having LEDs disposed in parallel lines · CPC title

• H05B45/20

  Controlling the colour of the light · CPC title

• H05B47/16

  by timing means · CPC title

• H05B45/37

  Converter circuits · CPC title

• G09G3/3208

  organic, e.g. using organic light-emitting diodes [OLED] · CPC title