Multi-mode portable lighting device
A portable lighting device, such as a flashlight, with a mechanical power switch and multiple operating modes is provided. The mechanical power switch is disposed in series with the controller for the lighting device and acts as the user interface to the controller to change modes of operation. Because the mechanical power switch is in series with the controller, the portable lighting device does not consume battery power when the mechanical switch is open. A state machine coupled to the controller is polled by the controller each time it is powered up to determine the operational mode of the lighting device. A regulating circuit is used to power a controller and light source. The regulating circuit converts between current regulation and voltage regulation.
1. A flashlight comprising:
a housing for receiving a power source comprising at least one battery;
a light source comprising at least one LED;
a main power circuit for connecting the light source to the power source, the main power circuit including a mechanical power switch; and
a regulating circuit that is coupled in series with the mechanical power switch and that powers the light source and a controller;
wherein the controller provides a pulse width modulating (PWM) signal to the regulating circuit to provide multiple modes of flashlight operation, such that during the on cycle of the PWM signal, the regulating circuit is a current regulating circuit that powers both the light source and the controller, and during the off cycle of the PWM signal, the regulating circuit is a voltage regulating circuit that powers the controller; and
wherein the controller is not powered by the power source when the mechanical power switch is opened in an off state.
2. The multiple mode portable lighting device of claim 1 , wherein the mechanical power switch is the only man to machine interface of the multiple mode portable lighting device.