Patent ID: 7400310

Claim:
A pulse signal drive circuit, comprising: a source of energy, said source of energy including a controllable current source; an energy storage device, coupled to the energy source, for receiving a substantially constant flow of current from the current source, said energy storage device including a capacitor; a switch circuit including a series connection of a load circuit and a switch, coupled to the energy storage device, for drawing repetitive pulses of substantially constant current from the energy storage device to generate corresponding pulse signals, said load circuit including a light emitting diode (LED) and said switch including a transistor having a main conductive path coupled between said LED and a source of common voltage (ground); and a source of a bistate drive signal coupled to the transistor for conditioning the main conduction path of the transistor to not conduct in response to a first state of the bistate drive signal and to conduct in response to a second state of the bistate drive signal.