Patent ID: 6748180
Filing Date: 2004-06-08
Classification: H01S,H04B

Abstract:
A driver circuit for a light emitting diode in an optical transmitter which converts an electrical signal into an optical signal, comprising:a charge switch; a capacitor having a first side connected to a higher voltage terminal of a power supply through said charge switch; a discharge switch coupled to a lower voltage terminal of said power supply, a second side of the capacitor being connected to said lower voltage terminal of the power supply, the anode of the light emitting diode being connected to a connection point of the charge switch and the capacitor, the cathode of the light emitting diode being connected to said lower voltage terminal of the power supply through said discharge switch; and a controller for closing the charge switch to charge the capacitor when a voltage on the capacitor reaches a preset low voltage threshold and for opening the charge switch when the voltage on the capacitor reaches a preset high voltage threshold, wherein the discharge switch is closed responsive to an intensity of the electrical signal and the capacitor thereby discharges through the light emitting diode to emit an optical signal corresponding to the electrical signal.