JP2002125329A - Power generation controller for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power generation controller for vehicles which can prevent a display lamp from lighting regardless of without relation to the power generating condition. SOLUTION: A battery B is charged with a 3-phase AC generator 10. One end of a charge lamp L is connected to the battery B, and the other end of the same lamp is connected to a lamp drive transistor T31. The charge lamp L is driven with the lamp drive transistor T31, according on the power generating condition of the 3-phase AC generator 10. The voltage of the connecting point P1 between the lamp drive transistor T31 and charge lamp L is detected with a voltage between the resistors R31 and R32, and when this voltage is equal to or higher than a prescribed voltage, the transistor T32 is turns on to inhibit drive of the lamp drive transistor T31. When the lamp drive transistor T31 is turned off, conduction between the connecting point P1 and resistor R31 is cut off with a conduction cut-off circuit 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular power generation control device for controlling a vehicular power generator mounted on a passenger car, a truck or the like.

[0002]

2. Description of the Related Art FIG. 2 shows a circuit diagram of a conventional vehicle power generation control device. As shown in FIG. 2, the power generation control device includes a three-phase AC generator 10, a power generation controller 20 that controls the generator 10, and a power generation detector 30 that detects a power generation state of the generator 10. The three-phase AC generator 10 includes a three-phase armature winding 11, a magnetic field winding 12, and a full-wave rectifier 13. The power generation controller 20 includes a transistor T21 and a voltage controller 21. The voltage controller 21 controls the magnetic field current flowing through the magnetic field winding 12 by driving the transistor T21 according to the battery voltage. Has become.

The power generation detector 30 includes a lamp drive transistor T31 for driving a charge lamp (display lamp) L, and turns on or off the charge lamp L according to the power generation state of the three-phase AC generator 10. It is configured as follows. Specifically, when the power generation is stopped when no power generation voltage is generated in the three-phase AC generator 10, the lamp driving transistor T
When the power is turned on to turn on the charge lamp L and the three-phase AC generator 10 generates power, the lamp drive transistor T31 is turned off to turn off the charge lamp L.

Here, if the charge lamp L is short-circuited while the lamp drive transistor T31 is on, an excessive current flows through the lamp drive transistor T31, and the transistor T31 may be destroyed. for that reason,
The power generation detector 30 detects the collector voltage of the lamp driving transistor T31, and turns off the lamp driving transistor T31 when the collector voltage rises due to an excessive current. Try to prevent.
Specifically, in the power generation detector 30, the collector of the lamp driving transistor T31 is connected to a resistor R3 connected in series.
1, R32, and the resistor R
The connection between the resistor 31 and the resistor R32 is connected to the base of the transistor T32. The collector of the transistor T32 is connected to the base of the lamp driving transistor T31, and the emitter of the transistor T32 is grounded. According to the circuit configuration, an excessive current flows through the lamp driving transistor T31 due to the short circuit of the charge lamp L, and when the collector voltage of the transistor T31 increases, the voltage between the resistors R31 and R32 (the transistor T32
, The base voltage of the transistor T32 rises and the transistor T32 turns on. As a result, the lamp driving transistor T31 is turned off, and an excessive current is prevented from flowing through the lamp driving transistor T31, and thus the lamp driving transistor T31 is prevented from being destroyed.

Japanese Patent Application Laid-Open No. 55-97151 discloses a technique for preventing breakdown of a transistor for driving an electric load due to an excessive current caused by a short circuit of the electric load. Also in the device of the publication, the collector voltage of the transistor for driving the magnetic field winding is detected, and when the collector voltage rises to a predetermined voltage or more when the transistor is turned on, it is determined that the magnetic field winding is short-circuited. Driving is restricted.

[0006]

By the way, in the vehicular power generation control device shown in FIG. 2, a circuit for detecting the collector voltage (a series circuit of the resistors R31 and R32) is employed to destroy the lamp driving transistor T31. However, a small amount of current always flows through the detection circuit. Therefore, when an LED (light emitting diode) that is lit even with a small current is used as the charge lamp L, the charge lamp L is always lit by the small current flowing through the detection circuit regardless of whether the lamp drive transistor T31 is on or off.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a vehicular power generation control device capable of preventing a display lamp from being turned on regardless of a power generation state. It is to be.

[0008]

According to the first aspect of the present invention, the battery is charged by the vehicle generator, and the display means is driven by the switching means according to the power generation state of the vehicle generator. You. Further, if the display lamp is short-circuited when the switching means is turned on, an excessive current may flow and the switching means may be destroyed. Therefore, the voltage at the connection point between the switching means and the display lamp is detected by the voltage detecting means, and when the detected voltage is equal to or higher than the predetermined voltage, the driving of the switching means is prohibited by the drive prohibiting means. Conventionally, when detecting the voltage at this connection point, a minute current flows into the voltage detection means and flows through the display lamp, so that when the switching means is off, the display lamp is turned on regardless of the power generation state. There was a thing. On the other hand, when the switching means is turned off, the conduction between the connection point and the voltage detection means is interrupted by the conduction interruption means, so that a very small current can be prevented from flowing through the display lamp, and the display can be performed regardless of the power generation state. The inconvenience of turning on the lamp can be avoided.

According to the second aspect of the present invention, the voltage detecting means is constituted by two resistors connected in series, and a voltage at a connection point is detected based on a voltage value between the resistors.
That is, a very small current flows through the resistor constituting the voltage detecting means, and the voltage at the connection point is detected by utilizing the resulting voltage drop.

According to the third aspect of the invention, the conduction between the connection point and the voltage detecting means is cut off by turning off the switching transistor. In this case, when the switching unit is turned off, the conduction between the connection point and the voltage detection unit can be accurately cut off in synchronization with the off timing,
This is practically preferable.

When the light emitting diode is used as the display lamp as in the invention of claim 4, the light emitting diode is lit by a very small current. Is interrupted. Therefore, lighting of the light emitting diode can be controlled accurately.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a circuit diagram of a vehicle power generation control device according to the present embodiment. In addition,
1, the same components as those of the conventional power generation control device shown in FIG. 2 are denoted by the same reference numerals.

As shown in FIG. 1, a power generation control device for a vehicle includes a three-phase AC generator 10, a power generation controller 20 for controlling the generator 10, and a power generation detector for detecting a power generation state of the generator 10. 30.

The three-phase AC generator 10 includes a three-phase armature winding 1.
1, a magnetic field winding 12 and a full-wave rectifier 13 are driven by an engine (not shown) to generate an AC electromotive force, convert the electromotive force to DC, and charge the battery B. . More specifically, the full-wave rectifier 13 includes 6
Diodes D11, D12, D13, D14, D1
5, three-phase full-wave rectification using D16,
Two diodes D11 to D16 connected in series are connected between the battery B and the ground. Also,
The connection of the three-phase armature winding 11 is a Y connection, and one end of each phase (one phase, two phase, three phase) windings 11a, 11, 11c is connected at one place, and the winding 11a of each phase is connected. , 11, 11c are connected to the connection between the diodes in the full-wave rectifier 13, respectively. Here, the other end of the one-phase winding 11a is located between the diode D11 and the diode D12.
The other end of the two-phase winding 11b is connected between the diode D13 and the diode D14, and the other end of the three-phase winding 11c is connected between the diode D15 and the diode D16. At the time of power generation by the three-phase AC generator 10,
When a current is applied to the magnetic field winding 12, a magnetic field is generated, and an AC electromotive force is generated in the three-phase armature winding 11 by the magnetic field and the rotational force of the engine. The AC electromotive force is rectified into DC by the diodes D11 to D16 of the full-wave rectifier 13 and supplied to the battery B.

The power generation controller 20 has a transistor T21 and a voltage controller 21. The collector of the transistor T21 is connected to the magnetic field winding 12, and the emitter of the transistor T21 is grounded. Further, the base of the transistor T21 is connected to the voltage controller 21.
The voltage controller 21 detects a battery voltage and outputs an ON or OFF command signal to the transistor T21 according to the battery voltage. Thereby, the magnetic field current of the magnetic field winding 12 in the three-phase AC generator 10 is controlled to keep the battery voltage at a constant voltage (for example, 14 V). In the power generation controller 20, the transistor T2
A diode D21 for back electromotive force bypass is connected in parallel with the magnetic field winding 12 between the collector 1 and the battery B.

The power generation detector 30 includes a lamp driving transistor T31 for driving the charge lamp L, and the charge lamp L depends on the power generation state of the three-phase AC generator 10.
Is turned on or off. In the present embodiment, when the three-phase AC generator 10 is stopped, the lamp driving transistor T31 is turned on to turn on the charge lamp L, and at the time of power generation, the lamp driving transistor T31 is turned off and the charge lamp L is turned off. Note that the lamp driving transistor T31 corresponds to a switching unit, and the charge lamp L corresponds to a display lamp. Further, as the charge lamp L, an LED (light emitting diode) that is lit even with a small current is used.

More specifically, in the power generation detector 30, a capacitor C31 and a resistor R33 for smoothing the generated voltage of the three-phase AC generator 10 are connected in series. One end (the resistor R33 side) of the series circuit of the capacitor C31 and the resistor R33 is connected to the one-phase winding 11a (the diode D11 and the diode D12) in the three-phase AC generator 10.
) And the other end of the series circuit (capacitor C
31) is grounded. In this case, the capacitor C is output via the resistor R33 by the voltage generated by the three-phase AC generator 10.
31 is charged. Also, a capacitor C31 and a resistor R3
3 is connected to the non-inverting input terminal of the comparator 31. The input terminal receives a voltage obtained by smoothing the voltage generated by the three-phase AC generator 10 (the charging voltage of the capacitor C31). You. On the other hand, the reference voltage Vref is input to the inverting input terminal of the comparator 31. Therefore, when the three-phase AC generator 10 is operated and the charging voltage of the capacitor C31 becomes higher than the reference voltage Vref, the output of the comparator 31 becomes H level, the three-phase AC generator 10 stops, and the When the charging voltage becomes lower than the reference voltage Vref, the output of the comparator 31 becomes L level.

The output of the comparator 31 is a transistor T33
And the input of the one-shot multivibrator 32. The collector of the transistor T33 is connected to a power supply (for example, 5 V) via a resistor R34, and the emitter of the transistor T33 is grounded.
The collector of the transistor T33 is connected to the base of the lamp driving transistor T31 via the resistor R35. The collector of the lamp driving transistor T31 is connected to the battery B via the charge lamp L. That is, one end of the charge lamp L is connected to the battery B, and the collector of the lamp drive transistor T31 is connected to the other end of the charge lamp L. The emitter of the lamp driving transistor T31 is grounded.

The output of the one-shot multivibrator 32 is connected to the base of a transistor T34.
When the output of the comparator 31 switches from the H level to the L level, the one-shot multivibrator 32 outputs an H level signal for a predetermined time to the transistor T34.
Output to the base. The collector of the transistor T34 is connected between the series-connected resistors R31 and R32, and the emitter of the transistor T34 is grounded.
The connection between the resistor R31 and the resistor R32 is connected to the base of the transistor T32, and the transistor T3
2 is connected to the base of the lamp driving transistor T31, and the emitter of the transistor T32 is grounded.

In the present embodiment, a lamp driving transistor T3 is connected by a series circuit including resistors R31 and R32.
A voltage detecting means for detecting a collector voltage (a voltage at a connection point P1 between the charge lamp L and the lamp driving transistor T31) is configured. Note that this resistor R3
1, R32 has a large resistance value,
The collector voltage (the voltage at the connection point P1) is detected by utilizing the voltage drop due to the minute current flowing through the resistors R31 and R32.

The power generation detector 30 includes a collector (connection point P1) of the lamp driving transistor T31 and a resistor R
A conduction cutoff circuit 35 for cutting off conduction with the series circuit of R31 and R32 is provided. The conduction cutoff circuit 35
It comprises an NPN transistor T35, a PNP transistor T36, and resistors R36 and R37. This conduction interruption circuit 35 corresponds to conduction interruption means.

Specifically, in the conduction cutoff circuit 35,
One end of the resistor R36 is connected to the resistor R34 and the transistor T3.
3 and the other end of the resistor R36 is connected to the base of the transistor T35. The collector of the transistor T35 is connected to the collector of the lamp driving transistor T31 via the resistor R37, and the emitter of the transistor T35 is grounded. The collector of the transistor T35 is connected to the base of the transistor T36, the collector of the transistor T36 is connected to the resistor R31 constituting the voltage detecting means, and the emitter of the transistor T36 is connected to the collector of the lamp driving transistor T31. It is connected.

Next, the operation of the power generation control device for a vehicle configured as described above will be described. First, when the vehicle shifts from a state in which the engine is rotating to a stopped state, the power generation of the three-phase AC generator 10 is stopped,
The output current of the three-phase armature winding 11 disappears. As a result, the charging voltage of the capacitor C31 decreases, and when the voltage becomes lower than the reference voltage Vref, the output of the comparator 31 becomes H
Switching from level to L level. At this time, the output of the one-shot multivibrator 32 is at the H level for a predetermined time, the transistor T34 is turned on, and the transistor T34 is turned on.
32 turns off. Further, when the output of the comparator 31 becomes L level, the transistor T33 turns off and the lamp driving transistor T31 turns on. As a result, a current flows through the charge lamp L, and the lamp L is turned on.

Further, since the transistor T33 is turned off, the transistor T35 is turned on in the conduction cutoff circuit 35, and accordingly, the transistor T36 is turned on. As a result, the collector (connection point P1) of the lamp driving transistor T31 and the resistor R31 conduct through the transistor T36. When the output of the one-shot multivibrator 32 becomes L level after a predetermined time elapses after the output of the comparator 31 switches, the transistor T
Since the switch 34 is turned off, the voltage between the resistors R31 and R32 changes according to the collector voltage of the lamp drive transistor T31 (the voltage at the connection point P1). That is, the collector voltage (the voltage at the connection point P1) is detected from the voltage between the resistors R31 and R32. Here, when the lamp drive transistor T31 is turned on, its collector voltage changes from H level to L level,
The voltage between the resistors R31 and R32 becomes L level.
Therefore, the transistor T32 turns off and the lamp driving transistor T31 continues to turn on.

When the charge lamp L is short-circuited while the lamp driving transistor T31 is on, an excessive current flows through the lamp driving transistor T31, and the collector voltage of the lamp driving transistor T31 increases. When the voltage rises, the voltage between the resistances R31 and R32 also rises, and when the voltage exceeds a predetermined voltage, the transistor T32 turns on. The turning on of the transistor T32 turns off the lamp driving transistor T31, thereby preventing the lamp driving transistor T31 from being destroyed due to an excessive current. That is, in the present embodiment, the transistor T32 corresponds to a driving prohibition unit, and the driving of the lamp driving transistor T31 is prohibited by the transistor T32.

On the other hand, when the vehicle shifts from the stopped state to the rotating state in the vehicle, the three-phase AC generator 10 starts generating power, and the output of the three-phase armature winding 11 is increased as the engine rotates. The current increases. As a result, the charging voltage of the capacitor C31 increases, and the voltage becomes the reference voltage V
When the value becomes ref or more, the output of the comparator 31 becomes H level. In this case, the transistor T33 turns on and the lamp driving transistor T31 turns off. Further, in the conduction cutoff circuit 35, the transistor T35 is turned off and the transistor T36 is turned off, so that the conduction between the collector (connection point P1) of the lamp driving transistor T31 and the resistor R31 is cut off by the transistor T36. Here, when the lamp driving transistor T31 is off, the collector voltage of the transistor T31 (the voltage at the connection point P1) is equivalent to the battery voltage via the charge lamp L. When the same voltage is applied to the detection circuit (a series circuit of the resistors R31 and R32), a small current flows in the circuit and the charge lamp L is turned on, but the conduction to the resistors R31 and R32 is cut off by the conduction cutoff circuit 35. Therefore, a small current does not flow through the charge lamp L,
Turns off.

According to the embodiment described above, the following effects can be obtained. (1) Since the connection point P1 and the resistor R31 are cut off by the conduction cutoff circuit 35 when the lamp drive transistor T31 is turned off, a very small current can be prevented from flowing through the charge lamp L, regardless of the power generation state. The disadvantage that the charge lamp L is turned on can be avoided. On the other hand, when the lamp drive transistor T31 is on, the connection point P1 and the resistor R31 are connected by the conduction cutoff circuit 35, so that the collector voltage of the lamp drive transistor T31 can be detected by the series circuit of the resistor R31 and the resistor R32. . When the voltage at the connection between the resistor R31 and the resistor R32 corresponding to the collector voltage becomes equal to or higher than a predetermined voltage (voltage at which the transistor T32 turns on),
The lamp driving transistor T is controlled by the transistor T32.
Since the driving of the transistor T31 is prohibited, the destruction of the transistor T31 can be prevented.

(2) Switching transistor T3
6, the conduction between the connection point P1 and the resistor R31 can be accurately interrupted when the lamp drive transistor T31 is turned off in synchronization with the off timing, which is practically preferable. .

(3) When a light emitting diode is used as the charge lamp L, the light emitting diode is lit by a small current flowing through the resistors R31 and R32. When the lamp driving transistor T31 is off, the connection point P1 and the resistor R are turned off.
Since the conduction with the LED 31 is interrupted, the lighting of the light emitting diode can be controlled accurately. In addition, since a light emitting diode can be used as the charge lamp L, power saving, miniaturization, and improvement of the life of the device can be achieved.

The present invention can be embodied in the following modes other than the above. In the above-described embodiment, the conduction interruption circuit 35 as the conduction interruption means includes the transistors T35 and T3.
6 and the resistors R36 and R37, but the invention is not limited to this. The point is that the connection point P1 is connected to the series circuit of the resistors R31 and R32 when the lamp driving transistor T31 is driven, while the series circuit of the connection point P1 and the resistors R31 and R32 is connected when the lamp driving transistor T31 is not driven. What is necessary is just to comprise the conduction | electrical_connection interrupting means so that connection with this may be cut off. For example, in the conduction interruption circuit 35, the transistor T36 disposed between the connection point P1 and the resistor R31 is not limited to a bipolar transistor, and the conduction interruption circuit 35 may be configured using a MOSFET or the like. .

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a vehicular power generation control device according to the present embodiment.

FIG. 2 is a circuit diagram showing a conventional vehicle power generation control device.

[Explanation of symbols]

10: three-phase AC generator as a vehicle generator, B: battery, L: charge lamp as display lamp, P1 ...
Connection points, R31, R32: resistors constituting voltage detecting means, T31: lamp driving transistor as switching means, T32: transistor as driving inhibiting means, T36: switching transistor.

Claims (4)

[Claims] 1. A vehicle generator for charging a battery, a display lamp having one end connected to the battery, and a display lamp connected to the other end of the display lamp according to a power generation state of the vehicle generator. Switching means for driving the display lamp, voltage detection means for detecting a voltage at a connection point between the switching means and the display lamp, and when a detection voltage of the voltage detection means is equal to or higher than a predetermined voltage,
A power generation control device for a vehicle, comprising: a drive prohibition unit that prohibits driving by the switching unit; and a conduction interruption unit that disconnects conduction between the connection point and the voltage detection unit when the switching unit is off. . 2. The power generation control device for a vehicle according to claim 1, wherein the voltage detection unit includes two resistors connected in series, and detects a voltage at the connection point based on a voltage value between the resistors. A power generation control device for a vehicle, characterized in that: 3. The power generation control device for a vehicle according to claim 1, wherein the conduction interrupting means has a switching transistor, and turns off the switching transistor to connect the connection point to the voltage detecting means. A power generation control device for a vehicle, which cuts off conduction. 4. The power generation control device for a vehicle according to claim 1, wherein the display lamp is a light emitting diode.