Patent ID: 6661116
Filing Date: 2003-12-09
Classification: B60R,H02J

Abstract:
A battery switching device loaded on a vehicle and adapted to supply power from a main battery or an auxiliary primary battery of the vehicle to an emergency signal transmitter for transmitting an emergency radio signal, comprising:a first voltage detection circuit for detecting whether or not an output voltage of the main battery is lower than a first detection voltage for making operable an emergency radio signal generation circuit of the emergency signal transmitter; a second voltage detection circuit for detecting whether or not an output voltage of the main battery is lower than a second detection voltage for making operable a transmitter section of the emergency signal transmitter; a manual switch for outputting an operation signal; a trigger generation unit which outputs a trigger signal when the operation signal and/or an air bag starting signal is entered; and a switching determination circuit, to which output signals are entered from said first and second voltage detection circuits and said trigger generation unit, wherein said switching determination circuit always switches from the main battery to the auxiliary primary battery when an output voltage of the main battery lower than the first detection voltage, and switches from the main battery to the auxiliary primary battery only when a trigger signal is entered in a case in which an output voltage of the main battery is equal to or larger than the first detection voltage and lower than the second detection voltage.