DRIVE CONTROL CIRCUIT, EMISSION CONTROL CIRCUIT, COMMUNICATION APPARATUS AND DRIVE CONTROL METHOD

• US 20090096382A1
• Filed: 12/15/2008
• Published: 04/16/2009
• Est. Priority Date: 02/27/2004
• Status: Abandoned Application

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: ITO, Tomoyuki, YAMAMOTO, Isao, IWAKI, Hiroyuki
• Application Number:
  US12/335,277
• Publication Number:
  US 20090096382A1
• Time in Patent Office: Days
• US Class Current: 315/250
• CPC Class Codes: H04M 1/22 Illumination; Arrangements for improving the visibility of characters on dials
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/24 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 47/155 Coordinated control of two or more light sources
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A drive control circuit sends out pulse signals of various pulse signals so as to control the light emission amount and luminance of LEDs by gradually increasing and decreasing the pulse width in predetermined cycles during predetermined periods based on parameters supplied from an LED drive controller that determine a first emission control processing period, a second emission control processing period, first to fourth slope periods and the like. The tone of an emitted color realized by a plurality of LEDs is controlled by synchronizing the periods of time of light emission control processings.

Claims

1. (canceled)

7. An emission control circuit, comprising:

a plurality of light emitting elements;

a drive circuit which drives respectively the light emitting elements by pulse width modulation;

an initial-value setting circuit which sets initial values of pulse width in the pulse width modulation to the light emitting elements, respectively;

a time setting circuit which sets a period during which the pulse width does not vary to the respective light emitting elements; and

a slope control circuit which varies the pulse width gradually in units of minimum modulation for each of the light emitting elements every time the period which is set for each of the light emitting elements.

2. An emission control circuit according to claim 7, wherein the period is set by a multiple of cycle of the pulse width modulation.

3. An emission control circuit according to claim 7, further comprising a total time setting circuit which sets a period of time during which the pulse width varies.

4. An emission control circuit according to claim 2, further comprising a total time setting circuit which sets a period of time during which the pulse width varies.

5. An emission control circuit according to claim 3, wherein the period of time during which the pulse width varies is set as a unit control cycle, further comprising a sequence control unit which controls and determines whether or not to carry out an emission control processing for varying the pulse width, per the unit control cycle.

6. An emission control circuit according to claim 4, wherein the period of time during which the pulse width varies is set as a unit control cycle, further comprising a sequence control unit which controls and determines whether or not to carry out an emission control processing for varying the pulse width, per the unit control cycle.

8. A communication apparatus including an emission control circuit therein, the emission control circuit comprising:

a plurality of light emitting elements;

a drive circuit which drives respectively the light emitting elements by pulse width modulation;

an initial-value setting circuit which sets initial values of pulse width in the pulse width modulation to the light emitting elements, respectively;

a time setting circuit which sets a period during which the pulse width does not vary to the respective light emitting elements; and

a slope control circuit which varies the pulse width gradually in units of minimum modulation for each of the light emitting elements every time a period which is set for each of the light emitting elements elapses.

9-10. -10. (canceled)