JPS6338693Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that warns when at least one of the battery voltage and the generator generated voltage is lower than a set voltage in a battery charging circuit.

Various devices have been proposed and used in the past to issue a warning when the voltage generated by the generator used to charge the battery is less than the set voltage. Since converters must absolutely prevent engine ignition errors, they constantly monitor battery voltage drops, which are a major cause of ignition errors, and issue a warning when the battery voltage drops below the set voltage. It has become necessary to encourage consumers to reduce their battery power consumption by giving them more power.

As a device for monitoring both the voltage generated by the generator and the battery voltage in this way, a circuit as shown in FIG. 1 can be considered, for example.

In Fig. 1, A is a known generator including a voltage regulator, B is a battery connected to be charged by generator A, and VDA is a voltage at or above a set voltage generated by generator A. VDB is connected to battery B via power switch S and relay R, and is a battery voltage detection circuit that detects whether the battery voltage is higher than a set voltage. be. The generator generated voltage detection circuit VDA and the battery voltage detection circuit VDB are connected in parallel with each other.
They are combined to form, so to speak, an OR circuit, and connected to the warning light W.

In this circuit, when the power switch S is closed, the contacts of the relay R are closed, and the battery voltage detection circuit
VDB detects the voltage of battery B, and when the battery voltage is lower than a set value, a warning light W is turned on regardless of the action of the generator generated voltage detection circuit VDA. In addition, when the power switch S is closed and the generator A does not generate a voltage higher than the set value, the generator generated voltage detection circuit VDA lights up the warning light W regardless of the action of the battery voltage detection circuit VDB. It acts on

Therefore, in the circuit shown in FIG. 1, in order to monitor the voltage generated by the generator A and the battery voltage, a generator generated voltage detection circuit VDA and a battery voltage detection circuit VDB are required separately, and the circuit configuration is This method has drawbacks such as complexity, increased cost, and increased size of the device.

The purpose of the present invention is to provide a device that monitors both the generator generated voltage and battery voltage with a simple circuit configuration. The battery charging circuit for a vehicle includes a generator 2 for charging the battery 1, which is driven by the battery 1, and the generator 2 includes alternating current generators 21 and 22, a rectifier circuit 23, and a voltage regulator 24. a first voltage detection circuit including a constant voltage element 33 connected between both poles of the generator 2 and conductive when the voltage between the poles is equal to or higher than a first predetermined voltage; a second voltage detection circuit including a constant voltage element 37 which is conductive at a second predetermined voltage or higher; and a constant voltage element 37 inserted into the second voltage detection circuit, a first switching element 36 that is turned on by conduction; a second switching element 41 that is turned on by conduction between the constant voltage element 37 of the second voltage detection circuit and the first switching element 36; A third switching element 43 that becomes non-conductive due to conduction of the second switching element 41; and a third switching element 43 that is connected to the battery 1 through the third switching element 43 to reduce the voltage drop of the battery 1 or the generator 2. A battery charging circuit for a vehicle is provided with a warning device 4 for giving a warning, and a resistor 39 for applying a part of the generated voltage outputted from the second switching element 41 to the first voltage detection circuit. will be achieved.

According to such a configuration, it is possible to simplify the circuit configuration, thereby avoiding an increase in costs and an increase in the size of the device, and also to prevent the voltage of the battery from decreasing to around the detection voltage of the first voltage detection circuit. This eliminates the problem of the warning device being activated intermittently due to the ripples contained in the voltage.

An embodiment of the present invention shown in FIG. 2 will be described below.

1 is a battery mounted on the vehicle; 2 is a generator driven by engine output (not shown) to charge the battery 1; 21 is an armature coil; 22 is a field coil; 23 is a rectifier circuit; and 24 is a voltage regulator. vessel, 2
Reference numeral 5 denotes an initial excitation circuit, and since this generator 2 is well known, detailed explanation will be omitted. 3 is a voltage detection circuit, which constitutes a battery voltage detection circuit which is a first voltage detection circuit by resistors 31, 32, 35 and a Zener diode 33 which is a constant voltage element, and the input terminal of this battery voltage detection circuit is connected to a relay. It is connected between the electrodes of the battery 1 via 5. Further, a generator generated voltage detection circuit, which is a second voltage detection circuit, is configured by the resistors 38 and 40 and a Zener diode 37 which is a constant voltage element.The input terminal of this generator generated voltage detection circuit is connected to the generator 2. It is connected to a control output circuit 26 that supplies power to the field coil 22 and voltage regulator 24. In both voltage detection circuits, the detection voltage is set by the breakdown voltage of the Zener diodes 33 and 37. The Zener diode 33 is conductive when the voltage of the battery 1 is higher than the first predetermined voltage, and the Zener diode 37 is connected to the generator. The second power generation voltage becomes conductive at a second predetermined voltage or higher. Further, a transistor 36, which is a first switching element, is inserted in the generator generated voltage detection circuit, and is turned on when the Zener diode 33 is turned on. The collector of this transistor 36 is connected to a transistor 41 which is a second switching element via a Zener diode 37 and a resistor 38, and the base is connected to a resistor 35 of a battery voltage detection circuit and a Zener diode 3.
3, and its emitter is connected to the cathode of battery 1. Further, the transistor 41 whose base is connected to the collector of the transistor 36 has an emitter connected to the control output circuit 2.
6, and its collector is connected to a relay 43, which is a third switching element, and is made conductive by the conduction of the transistor 36 and the Zener diode 37. The relay 43 has one end connected to the collector of the transistor 41 and an excitation coil connected to the cathode of the battery 1 at the other end, one end connected to the warning light 4 serving as a warning device, and the other end connected to the cathode of the battery 1. When the transistor 41 is conductive, the normally closed contact becomes non-conductive. The warning light 4 has one end connected to the normally closed contact of the relay 43, and the other end connected to the anode of the battery 1 via the power switch 6. 42 is relay 43
A flywheel diode is connected in parallel to the excitation coil, and 34 is a capacitor for noise absorption. Furthermore, 39 is a resistor connected to supply a part of the generated output of the generator 2 to the input terminal of the battery voltage detection circuit.

Next, the operation of the circuit shown in FIG. 2 will be described.

When the power switch 6 is closed and the generator 2 is not generating power, the voltage of the control output circuit 26 is the voltage supplied from the battery 1 via the initial excitation circuit 25, but the voltage generated by the generator is higher than this voltage. Since the detection voltage of the voltage detection circuit is set high, the transistor 41 does not conduct, the normally closed contact of the relay 43 remains closed, and the warning light 4 lights up. Therefore, when the power switch 6 is closed, the warning light 4 is always turned on, and it is possible to check whether there is any abnormality in the warning light itself.

After that, when the generator 2 starts generating electricity, the voltage of the control output circuit 26 increases as the electricity is generated, so if the voltage of the battery 1 is equal to or higher than the detection voltage, both the transistors 36 and 41 become conductive. The normally closed contact of the relay 43 is opened and the warning light 4 is turned off.

From this state, when the electrical load connected to battery 1 increases and the voltage of battery 1 drops below the detection voltage, Zener diode 33 becomes non-conductive, transistors 36 and 41 also become non-conductive, and relay The normally closed contact 43 closes and the warning light 4 lights up. When the warning light 4 is turned on, if the electric load is disconnected from the battery 1 as much as possible, the voltage of the battery 1 will be restored, and the Zener diode 33 will become conductive again, making it possible to turn off the warning light 4. In other words, the danger of engine ignition errors can be avoided.

In addition, the field coil 22 may be disconnected, the voltage regulator 24
If a voltage higher than the set value is not output to the control output circuit 26 of the generator 2 due to a failure in the generator 2, a disconnection of the control output circuit 26, etc., the Zener diode 37 becomes non-conductive, and the transistor 41 also becomes non-conductive. It becomes conductive and closes the normally closed contact of relay 43,
Warning light 4 goes out. In order for the warning light 4 to turn on, the failure of the generator 2 must be repaired. In other words, if left as is, the battery 1 will not be charged and will gradually become over-discharged. When the failure of the generator 2 is recovered, the Zener diode 37 becomes conductive again, so the transistor 41 also becomes conductive, and the warning light 4 goes out.

Note that when the transistor 41 is in a conductive state, the voltage of the control output circuit 26 of the generator 2 is supplied via the resistor 39 to the connection point between the resistors 31 and 32, which is the input end of the battery voltage detection circuit. Even if the electrical load connected to the battery 1 increases and the voltage of the battery 1 decreases, if the voltage decreases within a predetermined range, the Zener diode 33 is maintained in a conductive state by the voltage of the control output circuit 26. It is becoming possible to do so. This is because the main output circuit 27 of the generator 2, which is connected to charge the battery 1, contains ripples when the three-phase AC waveform is full-wave rectified.
If the voltage detected by the battery voltage detection circuit falls within the ripple amplitude without the circuit 9, the Zener diode 33 changes conduction and non-conduction at the ripple period. This is because the warning light 4 will repeatedly flash, and the voltage of the control output circuit 26 also contains ripples similar to the main output circuit 27.
By providing the resistor 39 circuit, the resistor 31
The voltage at the connection point between and 32 is increased, and the increased voltage value is made higher than the amplitude of the ripple, resulting in
It is possible to eliminate problems such as the blinking of the warning light 4. In other words, the voltage of the main output circuit 27 of the generator 2 and the voltage of the control output circuit 26 are always equal, but the voltage of the main output circuit 27 and the voltage of the battery 1 are not necessarily equal, and due to an increase in electrical load. When the voltage of the battery 1 decreases, the current flowing from the main output circuit 27 to the battery 1 is increased, so the voltage drop due to the wiring resistance of the wiring connecting the main output circuit 27 and the battery 1 increases. , a relatively large difference occurs between the voltage of the main output circuit 27 and the voltage of the battery 1. Therefore, when the voltage of the battery 1 decreases as described above, the voltage from the control output circuit 26 is transferred to the resistor 31.
By supplying the connection point between and 32, the voltage at this point can be increased. In addition, generator 2
If the voltage of the control output circuit 26 decreases and the Zener diode 37 repeats conduction and non-conduction with a ripple cycle, the warning light 4 will blink in that case as well, but the generator 2 Main output circuit 2
7. The voltage generated in the control output circuit 26 may become zero if there is a failure in the generator 2, but it will remain at an intermediate level voltage set by the Zener diode 37. Therefore, the flashing operation of the warning light 4 as described above is almost impossible.

Although a specific embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various other embodiments can be considered. enumerate.

(1) The generator and voltage regulator may be of any type as long as they can charge the battery.

(2) The input terminal of the generator generated voltage detection circuit may be connected to the main output circuit of the generator or between the neutral point and cathode of the armature coil.

(3) The voltage detection circuit may not include a Zener diode, but may be a combination of only a resistor and a transistor, and the detection voltage may be set by the threshold level of the transistor.

(4) The warning device may be a buzzer.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing an example of a circuit based on a conventional concept not based on the present invention, and FIG. 2 is an electric circuit diagram showing an embodiment of the present invention. 1... Battery, 2... Generator, 21... Armature coil (AC generator), 22... Field coil (AC generator), 23... Rectifier circuit, 24... Voltage regulator, 26... ...control output circuit (output circuit),
3... Voltage detection circuit, 33... Zener diode (constant voltage element), 36... Transistor (first
37... Zener diode (constant voltage element), 39... Resistor, 4... Warning light (warning device), 41... Transistor (second switching element), 43... Relay (third switching element).

Claims (1)

[Claims for Utility Model Registration] A generator 2 which is driven by the output of an on-vehicle engine and is used to charge a battery 1;
is connected between both poles of the battery 1 in a vehicle battery charging circuit including alternating current generators 21 and 22, a rectifier circuit 23, and a voltage regulator 24, and conducts when the voltage between the poles is equal to or higher than a first predetermined voltage. a first voltage detection circuit including a constant voltage element 33 that is connected to the output circuit 26 of the generator 2, and a second voltage detection circuit that includes a constant voltage element 37 that is connected to the output circuit 26 of the generator 2 and conducts when the generated voltage is equal to or higher than a second predetermined voltage. a first switching element 36 which is inserted into the second voltage detection circuit and is made conductive by the conduction of the constant voltage element 33 of the first voltage detection circuit; and the second voltage detection circuit. A second switching element 41 is made conductive when the constant voltage element 37 and the first switching element 36 of the circuit are made conductive; and a third switching element is made non-conductive when the second switching element 41 is made conductive. 43; a warning device 4 connected to the battery 1 via the third switching element 43 to warn of a voltage drop in the battery 1 or the generator 2; and an output from the second switching element 41. A battery charging circuit for a vehicle, comprising: a resistor 39 that applies a part of the generated voltage to the first voltage detection circuit.