PURPOSE: To certainly alarm the consumption of a battery before the voltage of the battery is lowered to transmission impossible voltage by the lowering in temp., by applying temp. correction to the voltage of the battery or the voltage coming to the judge reference of the consumption of the battery corresponding to the detection temp. of the battery.
CONSTITUTION: In the battery consumption detection circuit of a portable radio apparatus, the output voltage of a lithium battery 44 applied from an analogue switch 46 is divided by a temp. compensation circuit 50 and a resistor 52 to be imparted to a judge circuit 54 and the correction of temp. is performed corresponding to the temp. of the battery by the temp. compensation circuit 50. In the circuit 54, when the divided voltage corrected corresponding to the temp. of the battery was lowered to the reference voltage thereof, the consumption of the battery 44 is detected to be applied to a microcomputer 26 and alarm bit information is inserted in a transmission cord. When the radio signal contained in the transmission cord is received by the loop antenna provided to a vehicle side, the bit information alarming the consumption of the battery 44 is extracted by a receiving demodulation circuit 24 to be imparted to an alarm control circuit and an alarm lamp is lighted.
TAKEUCHI MIKIO
NAKANO KINICHIRO
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