| 摘要 |
PROBLEM TO BE SOLVED: To output the information liquid temperature and liquid level with one output signal line 13 and to prevent erroneous detection even when a potential difference occurs in a minus line of a storage battery. SOLUTION: The storage battery state detector 10 includes a liquid level detection electrode 11, a temperature detection resistor 12, and one output signal line 13. The liquid level detection electrode 11 is connected to the output signal line 13 through second and third switching elements 20, 21 and a second constant-current source 22. A first constant-current source 14 is connected to the output signal line 13 through a first switching element 16 turned on and off by an output of an oscillator circuit 15. The oscillator circuit 15 is composed of a timer IC 23 and a time constant setting circuit 24 connected to the timer IC 23 to set the on-off timing of a switch for capacitive discharge built in the timer IC 23. The temperature detection resistor 12 constitutes a part of the time constant setting circuit 24, and a power supply 17 of the timer IC 23 is powered from a storage battery 18. COPYRIGHT: (C)2011,JPO&INPIT |
