JPH0720342B2 - Power supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power supply device, and in particular to a terminal voltage of a battery for supplying a power to a refrigerator which can be mounted on a vehicle by a battery power source mounted on the vehicle. In the power supply device in which power can be supplied only when the above condition is satisfied, even if the terminal voltage is below a predetermined value, the power supply is forcibly maintained and the refrigerator can be tested, for example. The present invention relates to the power supply device.

[Conventional technology]

2. Description of the Related Art Conventionally, a refrigerator is operated by using a power source of a battery mounted on a vehicle, that is, by using, for example, a cigarette plug prepared in a passenger car.

In such a system, since power consumption by the refrigerator is relatively large, power is supplied to the refrigerator when the terminal voltage of the battery becomes a predetermined value, for example, 10.75 [V] or less. Is stopped. Then, when the terminal voltage is recovered to a predetermined value, for example, 12.75 [V] or more (the terminal voltage is recovered by the engine generator mounted on the vehicle), the power can be supplied again. ing.
That is, when the terminal voltage of the battery is 12.75 [V] or higher, or once it exceeds the terminal voltage, the relay circuit is turned on to supply electric power. After that, unless the terminal voltage of the battery becomes 10.75 [V] or lower, the relay circuit operates. When the terminal voltage of the battery continues to turn on and becomes 10.75 [V] or lower, the relay circuit turns off and power supply is stopped. The off state is continued until the terminal voltage of the battery becomes 12.75 [V] or higher. Such a hysteresis characteristic is to prevent chattering, and is performed by the functions of the resistors R ₆ and R ₁₀ in the voltage detection IC circuit 9 described later.

FIG. 4 shows a conventional configuration example. In the figure, reference numeral 1 is a battery, 2 is an engine generator, 3 is a load, 4 is a control circuit section, 5 is a relay circuit, 6 is a manual switch, 7 is a voltage dividing section, 8 is a reference voltage section, 9 is a voltage A detection IC circuit, 10 is a drive IC circuit, and 11 is a relay control transistor. In the figure, R ₁ to R ₁₀ and VR are resistive elements, C ₁ to C ₄ are capacitors, and D is
₁ is a diode, ZD is a zener diode, and LED is a light emitting diode.

When the terminal voltage of the battery 1 is at the first threshold value, that is, for example, 12.75 [V] or more when the manual switch 6 is turned on, the voltage of the voltage dividing unit 7 is larger than the voltage of the variable resistor VR, The detection IC circuit 9 emits a high output, and the IC circuit 10
Then, the relay circuit 5 is turned on via the transistor 11. As a result, the load 3 is fed to the refrigerator, for example. Under this condition, when the terminal voltage of the battery 1 falls below the second threshold value, that is, for example, 10.75 [V] or less, the voltage detecting IC circuit 9 outputs a low output and the relay circuit 5 is turned off. Under this condition, when the engine generator 2 is not started and the terminal voltage of the battery 1 is restored to the first threshold value or more, if the manual switch 6 is turned on, the relay is turned on. The circuit 5 is turned on again.

When the manual switch 6 is turned on and the terminal voltage of the battery 1 is equal to or lower than the first threshold value, for example, 12.75 [V], the voltage of the voltage dividing unit 7 is smaller than the voltage of the variable resistor VR, The relay circuit 5 is not turned on. That is, the load 3 is not supplied with power. Of course, when the manual switch 6 is turned on, the terminal voltage of the battery 1 reaches a second threshold value of 10.75.
Power is not supplied to the load 3 even if it is below [V].

If the manual switch 6 is left on, the relay circuit 5 is turned on and power is supplied to the load 3 when the terminal voltage of the battery 1 recovers to the first threshold value or higher.

[Problems to be solved by the invention]

In the case of the above-described conventional configuration, it is possible to eliminate the risk that the terminal voltage of the battery 1 undesirably drops and the vehicle cannot start, but as described above, the terminal voltage of the battery 1 is equal to or lower than the first threshold value. If so, the power cannot be supplied to the load 3 unless the engine generator 2 is started and the voltage is restored to the first threshold value or more.

Therefore, when the power cannot be supplied, for example, even when the refrigerator is operated for a very short period of time and the cooling function is checked for a test, the terminal voltage of the battery 1 can be checked by the engine generator 2. Even if is not recovered above the first threshold value, even the check becomes impossible. Further, while the load 3 is being supplied with power, the terminal voltage of the battery 1 is temporarily set to the second value.
Even if the terminal voltage of the battery 1 naturally recovers above the second threshold when the voltage drops below the second threshold, power cannot be supplied to loads other than the refrigerator as long as it does not exceed the first threshold. .

[Means for solving problems]

The present invention has solved the above-mentioned problems. Even if the power supply cannot be performed as described above by simply adding a predetermined means for inputting a signal to an existing circuit configuration, it is possible to perform a test or the like. Power is supplied for a short period of time.

FIG. 1 shows the principle of the present invention. In the figure, reference numeral 1 is a battery, 2 is an engine generator, 3 is a load such as a refrigerator, 4 is a control circuit section, 5 is a relay circuit, and FIG. Is compatible with, 1
Reference numeral 2 represents a forced activation means provided in the present invention.

The configurations and operations of the control circuit unit 4 and the relay circuit 5 shown in the figure are substantially the same as those of the conventional case shown in FIG.

In the case of the present invention, the forced activating means 12 is provided, and the forced activating means 12 is, of course, in the second state even if the terminal voltage of the battery 1 is below the first threshold value. Even if it is below the threshold value, the control circuit unit 4 is activated when the forced activation means 12 is activated, and the relay circuit 5 is turned on for a predetermined time, for example, several seconds.

[Action]

When the terminal voltage of the battery 1 is equal to or higher than the first threshold value when the manual switch 6 is turned on, the relay circuit 5 is turned on and power is supplied to the load 3. Then, under this power supply state, when the voltage becomes equal to or lower than the second threshold value, the relay circuit 5 is turned off. This point is no different from the conventional case.

However, in the case of the present invention, when the forced activation means 12 is operated with the manual switch 6 turned on, the voltage detection
The control circuit section 4 is activated by applying a signal to the input side of the IC circuit 9 so that the ON state is maintained for several seconds even if the terminal voltage of the battery 1 is below the second threshold value. . Of course, if the terminal voltage of the battery 1 has recovered to the second threshold value, that is, 10.75 [V] or higher at the time when the on-state has been connected for several seconds, the on-state is maintained.

Therefore, it becomes possible to test the cooling function of the refrigerator. In addition, even if the terminal voltage of the battery 1 temporarily drops below the second threshold value for some reason during power supply to the load 3, if the terminal voltage of the battery 1 becomes equal to or higher than the second threshold value, the load 3 will not be supplied to the load 3. Power supply can be restarted.

〔Example〕

FIG. 2 shows the construction of an embodiment of the present invention, in which the reference numerals 1 to 11, R ₁ to R ₁₀ , C ₁ to C ₄ , D ₁ , ZD and LEDs correspond to those in FIG. Corresponds to Figure 1. Further, reference numeral 13 in the drawing denotes an oscillation operation IC circuit, 14 an oscillator, 15 a counter, 16 a timer, R ₁₁ to R ₁₅ are resistive elements, C ₅ and C ₆ are capacitors, D _2
Through D ₄ are diodes and V _Ref is the power supply.

In the case shown, the oscillator 14 and the timer are used as the forced activation means 12.
It is marked with 16. Then, based on the output from the forced activation means 12, the resistance element R ₃ in the voltage dividing unit 7
And the potential at the connection point between R ₄ and R ₄ is forcibly maintained at a high level.

That is, in the illustrated case, the output from the oscillator 14 is the counter 15
Counted by. When the count value reaches a predetermined value (for example, after several minutes to several tens of minutes), the resistance element R
The output voltage of diode D ₂ is held at high level for several seconds by the time constant of ₁₅ and capacitor C ₆ . As a result, even if the terminal voltage of the battery 1 is below the second threshold value, if the manual switch 6 is turned on, I
The C circuit 9 is turned on for the above several seconds. That is, the relay circuit 5
Is turned on for at least a few seconds to supply power to the load 3. During this period, the refrigerator's cooling function is checked. Further, the ON state can be maintained as long as the terminal voltage of the battery 1 recovers to the second threshold value or less.

3 (A) and (B) are explanatory views for explaining another embodiment of the present invention. Incidentally, FIG. 3 (A) shows the circuit configuration shown in FIG. 2 as it is, and FIG. 3 (B) shows the configuration of another embodiment of the present invention. The reference numerals in the figure correspond to those in FIG. 2, but in the case of FIG. 3 (B), the connection mode of the capacitor C ₂ in FIG. 3 (A) is changed,
The capacitor C ₂ ′ constitutes the forced activation means 12 according to the present invention.

The difference between FIG. 3 (A) and FIG. 3 (B) is that the capacitor C ₂
However, there is no difference between the capacitors C ₂ and C ₂ ′ in removing the undesired noise component in the voltage dividing unit 7, although it is only the difference between the capacitor C ₂ ′ and the capacitor C ₂ ′.

However, in the case shown in FIG. 3 (B), at the moment when the manual switch 6 shown in FIG. 2 is turned on, the capacitor is connected via the diode D ₁ , the resistor element housing ₁ , the capacitor ₂ ′, and the resistor element housing _4. The charging current for C ₂ ′ flows. At this time, there is no electric charge remaining in the capacitor C ₂ ′.
The potential at the point indicated by is the current flowing through the resistance element R ₃ and the resistance element.
The value is proportional to the sum of the current flowing through R ₁ and the current flowing through the capacitor C ₂ ′. As a result, the IC circuit 9 outputs a high output. Then, the high output state is continued for a predetermined time (for example, several seconds) during which charges are accumulated in the capacitor C ₂ ′. In other words, even if the terminal voltage of the battery 1 is below the second threshold value,
The relay circuit 5 is turned on, and it becomes possible to check the cooling function of the refrigerator. If the terminal voltage of the battery 1 has recovered to the second threshold value or more after the above-mentioned several seconds, the ON state is maintained.

〔The invention's effect〕

As described above, according to the present invention, even if the terminal voltage of the battery is equal to or lower than the second threshold value, it is possible to allow power supply for at least several seconds as needed. Moreover, even if the terminal voltage of the battery 1 temporarily drops below the second threshold value for some reason during power supply to the load 3, the power supply to the load 3 can be restarted by the forced activation means. . And a slight modification of the existing configuration is sufficient.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention, FIG. 2 is an embodiment configuration, FIG. 3 is an explanatory diagram for explaining another embodiment, and FIG. 4 is a conventional configuration. In the figure, 1 is a battery, 2 is an engine generator, 3 is a load, 4 is a control circuit, 5 is a relay circuit, 6 is a manual switch, 7 is a voltage divider, 9 is a voltage detection IC circuit, and 12 is a voltage detection IC circuit. This means forced activation.

Claims (1)

[Claims] 1. A battery, a control circuit section for detecting a terminal voltage of the battery, a relay circuit which is turned on / off by an output from the control circuit section, and electric power from the battery via the relay circuit. And a load to be fed, the control circuit unit turns on the relay circuit when the terminal voltage of the battery exceeds a predetermined first threshold value, and the terminal voltage of the battery is the first voltage. In the power supply device configured to maintain the ON state until it decreases to the second threshold value equal to or lower than the threshold value and turn off the relay circuit when the second threshold value is equal to or lower than the second threshold value, The terminal voltage of the battery and the first
It has a voltage detection IC circuit for comparing with the threshold value of, and activates the function of turning on the relay circuit by the control circuit section for the input terminal side of the voltage detection IC circuit, and at least a predetermined value is set. Even when the terminal voltage of the battery is equal to or lower than the second threshold value, the control circuit unit is provided with at least the predetermined control circuit section even if the terminal voltage of the battery is equal to or less than the second threshold value. A power supply device characterized in that the relay circuit is forcibly kept in an ON state by the control circuit section for a period.