This article introduces a DC/DC converter for driving Lumileds white LEDs from a variety of power sources. The converter combines a traditional voltage feedback loop and a unique current feedback loop to operate as a constant-voltage, constant-current DC/DC converter. No external op amps are required, saving cost and space.
This document is a design note (DN340) detailing application circuits for the Linear Technology LT1618 IC. It explains how to use this boost converter to drive 1W white LEDs with constant current, addressing efficiency and component count challenges associated with standard DC/DC converters.
| Maximum peak current limit | 1.5A |
|---|---|
| Switching frequency | 1.4MHz |
| Package type | 10-pin thermally enhanced DFN package |
| Efficiency (Li-ion source) | approximately 70% |
| Efficiency (2-Alkaline Cell Source) | 85% |
| Efficiency (Automotive source) | approximately 70% |
The monolithic low side switch has a maximum peak current limit of 1.5A.
Yes, it can power a 1W white LED from a single lithium-ion battery with approximately 70% efficiency.
No, no external op amps are required because it combines traditional voltage feedback and a unique current feedback loop.