Drive circuit and light emitting device
US11109459B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | May 23, 2018 |
| Grant date | Aug 31, 2021 |
| Priority date | — |
| Expiry date | May 23, 2038 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/30
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A drive circuit 3 includes a power source 11; current control units 12-1 to 12-n configured to control the amount of currents supplied to a light emitting element in accordance with a pulse modulation signal; and a calculation unit 13 configured to change a duty ratio of a pulse modulation signal. The current control units 12-1 to 12-n include a first switching element 21 configured to be switched on/off in accordance with a pulse modulation signal; and a second switching element 22 configured to be switched on/off in accordance with an inversion signal of the pulse modulation signal input to the first switching element 21; and an inductor 23. The first switching element 21 and the inductor 23 are serially connected between the power source and the light emitting element. The second switching element 22 is connected between ground 25 and a contact point 24 of the first switching element 21 and the inductor 23. The two or more current control units 12-1 to 12-n are connected in parallel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.