Light emission control circuit uniformly and non-uniformly controlling a plurality of light-emitting elements
US7391406B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 2004 |
| Grant date | Jun 24, 2008 |
| Priority date | — |
| Expiry date | Apr 5, 2026 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/30
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A booster converter outputs a boosted voltage. A plurality of LEDs emit light of respective colors. The transistors establish or shut connection between the LEDs and a main driving circuit. A variable current circuit feeds a current to drive the LEDs. A PWM control unit effects control to cause the LEDs to emit light with respective tones of color. A PWM circuit executes PWM modulation in accordance with an instruction from the PWM control unit. A setting control unit 138 controls the magnitude of the driving current fed by the variable current circuit in accordance with an instruction from a second light emission control unit. In an image pickup mode, an additional driving circuit feeds a driving current to the LEDs so that the LEDs operate as an electronic flash.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.