Portable lighting devices
A flashlight uses a reverse battery protection circuit to prevent current from flowing in a power control circuit when at least one battery is held in a reversed orientation, rather than a correct orientation, in a battery compartment of the flashlight.
1. A flashlight, comprising:
a light source;
a power source comprised of at least one battery held in a battery compartment;
a power control circuit that electrically couples the light source to the power source when said at least one battery is held in a correct orientation in the battery compartment; and
a reverse battery protection circuit that prevents current from flowing in the power control circuit when said at least one battery is held in a reversed orientation in the battery compartment; wherein
the reverse battery protection circuit is comprised of a p-channel metal-oxide semiconductor field-effect transistor (“PMOS”), a source of the PMOS is connected to a positive electrode of the at least one battery held in the correct orientation in the battery compartment or to a negative electrode of the at least one battery held in the reversed orientation in the battery compartment, a gate of the PMOS is connected to a ground, and a drain of the PMOS is connected to an internal voltage supply in the power control circuit.
2. A method for preventing a flashlight from operating when at least one battery is inserted into a battery compartment of the flashlight in a reversed orientation, comprising the steps of using a reverse battery protection circuit to prevent current from flowing in a power control circuit when said at least one battery is held in a reversed orientation, rather than a correct orientation, in the battery compartment and operating the flashlight in the desired mode of operation when the electrical circuit is reconnected after less than the preselected period of time.