JPH07322531A - Power supply for car - Google Patents

Abstract

PURPOSE:To obtain a power supply for car which serves as a backup power supply for the electronic apparatus in a car regardless of the switching of a main power supply. CONSTITUTION:The power supply for electronic apparatus in a car requiring backup comprises secondary batteries 3, 4, and diodes 5, 6 having anodes being applied with the output voltages from the secondary batteries 3, 4 and interconnected cathodes and feeding power to circuits in a car audio unit requiring backup, e.g. memories. The power supply further comprises a switch 2 for selecting one of the outputs from the secondary batteries 3, 4 as the main power supply for the car audio unit 1, and a circuit 8 for comparing the voltages of the secondary batteries 3, 4 and turning the switch 2 from the secondary battery having dropped voltage to the secondary batter having normal voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle power supply device for supplying electric power to an on-vehicle electronic device requiring a backup power source.

[0002]

2. Description of the Related Art There has been no vehicle-mounted power supply device that has a memory or the like and can function as a backup power source regardless of switching of the main power source for vehicle-mounted electronic equipment requiring backup.

An object of the present invention is to provide an in-vehicle power supply device which is equipped with a memory or the like and can also function as a backup power source for an in-vehicle electronic device requiring a backup regardless of switching of a main power source.

[0004]

An on-vehicle power supply device of the present invention is an on-vehicle power supply device for supplying electric power to an on-vehicle electronic device which requires backup, and includes two or more secondary batteries and the two or more two batteries. The output voltage of the secondary battery is applied to each of the anodes and the cathodes are commonly connected to each other to select a diode for supplying power to a circuit in the on-vehicle electronic device requiring backup and one of the outputs of the secondary battery. Switching control for switching the selection means from the secondary battery whose voltage has dropped to the secondary battery side where the voltage has not dropped by comparing the voltage of the secondary battery with the selection means that supplies the main power of the on-vehicle electronic device. And means.

[0005]

In the vehicle-mounted power supply device of the present invention, the voltage in the secondary battery is compared to two or more in the switching control means, and the secondary battery side whose voltage has been reduced by the selection means under the control of the switching control means. Is switched to the secondary battery side in which the voltage has not dropped, and the switched secondary battery serves as the main power source to supply power to the on-vehicle electronic device. On the other hand, the circuit requiring backup in the vehicle-mounted electronic device is backed up by the power of the secondary battery having the highest output voltage via the diode.

Therefore, even if there is a momentary interruption of the power supply voltage during the switching in which one of the secondary batteries is switched by the selection means under the control of the switching control means, during this period, the voltage of the highest voltage among the two or more power supply devices is the highest. The circuit requiring the backup in the vehicle-mounted electronic device is backed up from the high secondary battery via the diode, and the backup power is not interrupted. As a result, the information stored in the memory of the on-vehicle electronic device such as the radio receiver may be lost from the audio device equipped with the memory, the timer, etc. that needs to be backed up and the memory storing the broadcast station list etc. There is no such thing.

[0007]

EXAMPLES The present invention will be described below with reference to examples. Figure 1
FIG. 1 is a block diagram showing a configuration of an embodiment of a vehicle-mounted power supply device according to the present invention.

The vehicle-mounted power supply device according to this embodiment includes a secondary battery 3
And 4, the secondary batteries 3 and 4 are supplied to the changeover switch 2, and the one of the two selected by the changeover switch 2 is supplied.
The power from the secondary battery is supplied to, for example, the vehicle-mounted audio device 1 as the vehicle-mounted electronic device. On the other hand, the secondary batteries 3 and 4
Output voltage is applied to the anodes of the diodes 5 and 6, respectively, and the cathode of the diode 5 and the cathode of the diode 6 are connected in common, and the resistor 7 is connected through the diode 5 or 6 to the memory etc. in the vehicle audio device 1. Circuits that require backup (hereinafter simply referred to as memory, etc.)
Supply power for backup. Diode 5
6 and 6 are for automatically selecting the secondary battery on the high potential side, and are inserted to prevent backflow, and the resistor 7 requires only a small amount of current for backup. It is connected.

The output voltages of the secondary batteries 3 and 4 are supplied to the changeover control circuit 8, and the changeover control circuit 8 compares the two output voltages and changes over the changeover switch 2 so as to select the secondary battery having the higher output voltage. Control. Reference numeral 11 is a charging device, and the charging device 11 is connected so as to charge the secondary batteries 3 and 4 through diodes 9 and 10 for preventing backflow separately.

In the on-vehicle power supply device of the present embodiment configured as described above, the changeover switch 2 is used to change the voltages of the secondary batteries 3 and 4 in the changeover control circuit 8 and select the higher one. Controlled by 8. Therefore, the in-vehicle audio device 1 operates by being supplied with power from the secondary battery 3 or 4 having the higher voltage as the main power source to the in-vehicle audio device 1. On the other hand, the output voltages of the secondary batteries 3 and 4 are supplied to the diodes 5 and 6, and the higher output voltage is supplied to the memory or the like in the vehicle audio device 1 through the resistor 7.

Under control of the switching control circuit 8, the secondary battery 3
And 4 are switched by the changeover switch 2, a momentary interruption occurs. Even during this momentary interruption, power is supplied from the secondary battery 3 or 4 to the memory or the like in the vehicle audio device 1 via the diode 5 or 6. Since the data is supplied and the memory and the like in the vehicle-mounted audio device 1 is backed up, the stored contents of the memory and the like in the vehicle-mounted audio device 1 will not be lost.

When the output voltage of the secondary batteries 3, 4 drops to a predetermined value due to the discharge of the secondary batteries 3, 4, the diode 9,
The secondary batteries 3 and 4 are automatically charged by the charging device 11 via 10. Therefore, the one with the higher output voltage
If the secondary battery has not dropped to the predetermined value for charging and the output voltage of the secondary battery with the lower output voltage has dropped to the predetermined value for charging, the secondary battery is charged. Become.
As a result, when the output voltage of the charged secondary battery is higher than the output voltage of the other secondary battery due to charging, this is detected by the changeover control circuit 8 and the changeover switch 2 changes the output voltage of the secondary battery. Switching will be performed.

In the above-described embodiment, the case where two secondary batteries are used has been illustrated, but the same constitution can be made even if a plurality of secondary batteries are used.

For example, in an electric vehicle in which a vehicle is driven by electric power from a power battery, a power battery having a high voltage of about 200 V is used for other devices such as an on-vehicle audio device. A DC-DC converter or the like is required to obtain the low voltage. However, in the above-described vehicle-mounted power supply device of the present embodiment, since the power consumption is small, even if a small secondary battery is used, it can be used for a long time, and a plurality of secondary batteries are used by switching. For,
It can be easily configured such that a DC-DC converter is not required. Further, when using the charging device, a solar charger or the like can be used.

[0015]

As described above, according to the on-vehicle power supply device of the present invention, it is compact because it is composed of a plurality of secondary batteries, and it is possible to supply power to the on-vehicle electronic equipment as the main power source and also as the backup power source. There is an effect that it is possible to back up the memory and the like in the in-vehicle electronic device without instantaneous interruption.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an in-vehicle power supply device according to the present invention.

[Explanation of symbols]

 1 In-vehicle audio device 2 Changeover switch 3 and 4 Secondary battery 5, 6, 9 and 10 Diode 8 Changeover control circuit 11 Charging device

Claims (1)

[Claims] 1. An on-vehicle power supply device for supplying electric power to an on-vehicle electronic device requiring backup, comprising two or more secondary batteries, and output voltages of the two or more secondary batteries applied to respective anodes. A diode having a cathode commonly connected to supply power to a circuit in the vehicle-mounted electronic device that requires backup, and a selection of one of the outputs of the secondary battery to supply the selected power source as the main power source of the vehicle-mounted electronic device. A vehicle-mounted power supply comprising: means for comparing the voltage of the secondary battery; and switching control means for switching the selecting means from the secondary battery whose voltage has dropped to the secondary battery side whose voltage has not dropped apparatus.