Vehicle electric power supply apparatus

Abstract

A control unit (14) of a vehicle electric power supply apparatus (10) controls an opening and closing unit (16) to set a switch (15) to an OFF state and a voltage detection unit (26, 25) to detect an output voltage (VB) of a first power source (12) and an output voltage (VC) of a second power source (11) when a second electric load (20) is to be driven, and the control unit inhibits driving of the second electric load when the absolute value of the difference between the output voltage of the first power source and the output voltage of the second power source detected by the voltage detection unit is a predetermined first threshold value or less over a predetermined length of time.

Description

technical field [0001] The present invention relates to a power supply device for a vehicle. Background technique [0002] Conventionally, a power supply device for a vehicle is known, wherein a DC-DC converter is connected between a main power supply connected to an electric load and a sub power supply connected to a generator for starting an engine, and a power supply is provided between the main power supply and the sub power supply. switch (for example, refer to Japanese Patent Application Laid-Open No. 2010-195336). [0003] According to the power supply device for a vehicle of the prior art described above, it is preferable to prevent unexpected charging and discharging between the main power supply and the sub power supply by detecting whether or not there is an ON failure in which the switch is fixed in the on state. [0004] In addition, according to the vehicle power supply device of the prior art described above, when the output voltage of the auxiliary power sup...

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Problems solved by technology

[0004] In addition, according to the vehicle power supply device of the prior art described above, when the output voltage of the auxiliary power supply falls below a predetermined value, and the voltage required to start the engine cannot be ensured by the generator, the switch is turned off and the main power supply is directly connected to the power supply. generator power

However, only judging whether the output voltage of the auxiliary power supply detected by the voltage sensor is lower than a predetermined value cannot actually properly judge whether or not the engine can be started by the generator, and there is a possibility of unnecessary direct power supply from the main power supply to the generator.

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