Patent ID: 9713217
Date: 2017-07-18
CPC Classifications: H05B,Y02B

Claim:
1. A brightness control circuit for an LED emitter, comprising: an LED and a transistor connected in series across a DC voltage source having a source terminal and a return terminal; a microprocessor having a non-volatile memory, the microprocessor connected across the DC voltage source, and an output of the microprocessor connected to an input of the transistor; a switch actuator circuit comprising at least one single pole, momentary, non-latching switch coupled between at least one input of the microprocessor and the return terminal for entering user commands to select discrete first, second and third brightness levels of the LED emitter; and a program stored in the non-volatile memory containing control instructions defining a sequence of pulse width modulated signals in a repeating first defined interval and responsive to the operating state of the switch actuator circuit for controlling the discrete first, second and third brightness levels of the LED emitter corresponding respectively to high, medium, and low brightness; wherein the program cycles through each brightness level in a predetermined sequence when a switch contact of the switch actuator is held closed; or the program stops within a brightness level in the sequence when the switch contact of the switch actuator is released to select that brightness level.