Laser driver for controlling electrical current passed to a laser in an optical disc system
US5878015A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Mar 2, 1999 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K41/0356
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A laser driver for controlling an electrical current supplied to a laser in an optical disc system. The laser driver includes pass transistors for delivering electrical current to the laser, an operational amplifier for setting a reference voltage on the bases of the pass transistors, and a CMOS buffer for applying a drive voltage to emitter circuits of the pass transistors. The drive voltage has a first voltage level and a second voltage level, and the electrical current is supplied to the emitter circuits only when the drive voltage is at the first voltage level. The laser driver further includes a switch for switching the drive voltage between the first voltage level and the second voltage level so that electrical power is consumed only when the laser is energized and enhanced rise and fall switching characteristics are thereby achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.