Patent ID: 7627353
Filing Date: 2009-12-01
Classification: H04B

Abstract:
1. A power-saving auto-off circuit for a wireless transmitter modulated by a baseband signal, said auto-off circuit comprising: a battery; a voltage regulator powered by said battery for providing a regulated voltage output; current-switching means receiving as its input the output of said voltage regulator and having a controlling input; a timing circuit having a reset state and a non-reset state and held initially in a non-reset state, said timing circuit having an output in communication with said controlling input of said current-switching means, wherein when said timing circuit is in a non-reset state it switches said current-switching means to an off state at the end of a predetermined amount of time unless said timing circuit is reset, and wherein when said timing circuit is in a reset state it switches said current-switching means to an on state and allows current to flow through said current-switching means to the transmitter; a baseband signal detection circuit for detecting the presence of the baseband signal and having an input in communication the source of the baseband signal and an output in communication with a controlling input of said timing circuit, wherein when said baseband signal detection circuit detects the presence of the baseband signal it resets said timing circuit, causing said current-switching means to transition to an on state, thus providing power to said transmitter, and continues to keep said timing circuit in a reset state while the presence of the baseband signal is detected, and wherein when said baseband signal detection circuit no longer detects the baseband signal, said timing circuit waits for the predetermined amount of time before switching said current-switching means to an off state, thus cutting off power to the transmitter.