Patent ID: 6087815
Filing Date: 2000-07-11
Classification: B25F,H01M,Y02E

Abstract:
A DC to DC converter for a handheld electrical device, comprising:a DC power input;a power conversion circuit coupled to said input for receiving power at a first voltage and having an output, said conversion circuit selectively gating power at a desired second voltage different from the first voltage to the output, the output adaptable to be coupled to a power input of the handheld electrical device;an output impedance element of the conversion circuit connected to the output, a logic circuit coupled to the output impedance element by a voltage sense line, a control path coupling the logic circuit to the conversion circuit, the logic circuit sensing a drop in voltage across the output impedance element as an indication that the handheld electrical device has been turned on by the user and that power is now required, the logic circuit, in response to sensing the drop in voltage, transmitting a control signal to the conversion circuit, the conversion circuit gating DC power at the second voltage responsive to receiving the control signal; anda trickle current path from the input of the conversion circuit to the output of the conversion circuit to permit a sense voltage to reside across the output impedance element when the electrical device is not turned on.