LED current bias control using a step down regulator
US7323828B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 2005 |
| Grant date | Jan 29, 2008 |
| Priority date | — |
| Expiry date | Apr 25, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B45/375
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A step down switching regulator circuit that is particularly well-suited to drive high power LEDs includes a crossover conduction mode (XCM) control circuit that maintains operation at the crossover point between continuous conduction mode (CCM) and discontinuous conduction mode (DCM). This XCM operation provides an inductor current waveform that ramps up and down between zero and a desired maximum current. One or more comparators in the XCM control circuit can be used to control switching between the inductor current ramp up and ramp down phases. In this manner, complex feedback loop logic and PID controlled PWM signal generation logic can be avoided, and the need for external sense resistors and associated interface pins can be eliminated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.