Patent ID: 7269194
Filing Date: 2007-09-11
Classification: H01S

Abstract:
1. An apparatus for driving a laser the apparatus comprising: a current sink; a differential pair of PNP transistors, each transistor having a base, emitter and collector the bases being coupled together, and the emitters being coupled to a supply voltage Vcc, a differential pair of NPN transistors, each transistor having a base, emitter and collector the emitters being joined at a junction with the current sink, the bases providing the input across which an input signal is developed, a load junction of the collector of one of the PNP transistors and one of the collectors of one of the NPN transistors that is coupled to a laser load; wherein the load junction is coupled to the base junction of the PNP transistors by a feedback resistor; and wherein the feedback resistor is coupled between the load junction and the base of a PNP feedback transistor, and the emitter of the PNP feedback transistor is coupled to the base junction of the PNP differential transistor pair.