Feedback-controlled LED switching
US6825619B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 8, 2002 |
| Grant date | Nov 30, 2004 |
| Priority date | — |
| Expiry date | Aug 8, 2022 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/14552
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An oximeter has an op-amp with a first input, a second input, and an output, the first input being directly connected to a reference voltage. A switch has an input connected to the output of the op-amp, and has a plurality of switch outputs. A transistor has a control input connected to one of the plurality of outputs, and has a current source terminal and a supply terminal. A diode is connected to the current source terminal of the transistor. The supply terminal of the transistor is connected both to the second input of the op-amp and to a second one of the plurality of switch outputs. The switch is thereby in a feedback loop of the op-amp, effecting a feedback-controlled switch for switching the diode on and off.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.