JPS5847806Y2 - semiconductor voltage regulator - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a semiconductor voltage regulator that controls the output voltage of an alternator driven by, for example, an internal combustion engine to a predetermined value.

First, a conventional device of this type is shown in FIG. 1 and will be explained.

In Fig. 1, 1 is equipped on a vehicle (not shown), and is equipped with an engine (
This is an alternating current generator driven by an AC generator (not shown), and has an armature coil 101 and a field coil 102 connected in a three-phase star shape.

2 is a full-wave rectifier that rectifies the AC output of the generator 1; 3;
is a voltage regulator that controls the output voltage of the generator 1 to a predetermined value, and is composed of the following parts.

That is, 301 is a surge absorption diode connected to both ends of the field coil 102, and 302 is a surge absorbing diode connected to both ends of the field coil 102.
The first transistor 303 constitutes a switching element that blocks the field current of 2, and 303 is the base of this transistor 302.
A resistor 304 inserted between the ground and the transistor 3
A resistor 305 is connected in series with the base circuit of transistor 302, and a second transistor 306 is inserted between the base of transistor 305 and ground. The resistor 307 detects the output voltage of the generator 1 and constitutes a detection element that is energized when the output voltage reaches a predetermined value.
Diodes 308 and 309 are connected in series to form a voltage divider circuit, and 310 is the first resistor.
A negative feedback capacitor is connected between the collector and base of the transistor 305, 311 is a positive feedback resistor, and 312 is a positive feedback capacitor.

4 is a storage battery, and 5 is a key switch.

The operation of the conventional device circuit configured as above will be explained.

First, when the key switch 5 is closed when starting the internal combustion engine, a base current is supplied from the storage battery 4 to the transistor 302 via the key switch 5 and the resistor 304, and the transistor 302 becomes conductive.
A field current flows from the storage battery 4 to the field coil 102 through the storage battery 4, and a field magnetomotive force is generated.

In this state, when the engine starts and the generator 1 is driven,
An alternating current output is induced in the armature coil 101 according to the rotation speed, and this output is full-wave rectified by the full-wave rectifier 2.

Here, when the rectified output voltage is below a predetermined value, the resistor 308
, 309 is still low, the zener diode 307 maintains a non-conducting state, and the supply of field current is maintained, thereby reducing the output of the generator 1. The voltage increases as the rotational speed increases.

After that, when the rotational speed of the generator 1 further increases and the output voltage exceeds a predetermined value, the potential of the voltage dividing point of the voltage dividing circuit also increases, thereby causing the zener diode 307 to conduct.
A base current flows through the Zener diode 307 to the transistor 305, making the transistor 305 conductive.

If this transistor 305 conducts, the transistor 3
02 becomes non-conductive, cutting off the field current of the field coil 102 and lowering the output voltage of the generator 1.

When this output voltage decreases to a predetermined value, the Zener diode 307 and the I transistor 305 become non-conductive again, the transistor 302 becomes conductive, and the field coil is energized, so that the output voltage of the generator 1 increases again. Rise.

By repeating the above-described operations, the output voltage of the generator 1 is controlled to a predetermined value, and the storage battery 4 is charged to the predetermined voltage using this control voltage.

Here, a resistor 303 inserted between the base of the transistor 302 and ground is inserted for the purpose of increasing the collector-emitter breakdown voltage of the transistor 302 and preventing destruction even if a high surge voltage is applied from the outside. .

Also, resistors 306, 311. The capacitors 312 are each connected in series to form a positive feedback circuit, and the transistor 3
The intermittent operation of 02 is accelerated and reliably performed, thereby reducing the intermittent loss that occurs when intermittent.

On the other hand, when the above-mentioned positive feedback circuit is provided as in this conventional example, the negative feedback capacitor 310 connected between the collector and base of the transistor 305 suppresses unstable operation such as oscillation caused by the positive feedback circuit. Not only does this prevent malfunctions caused by high-frequency noise, which has occurred since Φ5, but the average voltage of the regulated voltage decreases due to the rectified output ripple, which increases especially when the generator 1 is under heavy load. It has the function of correcting the phenomenon of deterioration.

In other words, the capacitor 3 to which all negative feedback functions are connected
10 has the function of giving a time delay to the cutoff of the field current even when the Zener diode 307 conducts according to the ripple voltage mentioned above, so that the peak value of the adjustment voltage is adjusted as desired. It is possible to correct the phenomenon in which the voltage value becomes larger than the voltage value, and the adjustment voltage substantially decreases due to ripple.

It is more effective if the capacitance of this capacitor 310 is larger to some extent, but when the transistor 305 is cut off, the capacitor 310
This is the same as when the resistor 303 and the base-emitter of the transistor 302 are inserted in parallel with each other to reduce the negative feedback capacitance, and the voltage drop when a load is connected to the generator 1 increases.

In particular, when these voltage regulators are constructed from hybrid thick film integrated circuits, etc., the capacitor 310 has a large external size and is expensive, and at the same time, large capacitors are susceptible to temperature cycles and have low overall reliability. - There were some drawbacks.

This invention provides an excellent semiconductor voltage regulator that overcomes the above-mentioned drawbacks.

The embodiment shown in FIG. 22 will be described below.

In FIG. 2, 313 has a cathode connected to the connection point between the transistor 305 and the negative feedback capacitor 310, and a base resistor 30.
A diode 314 whose anode is connected between the transistor 4 and the base of the transistor corrects the forward voltage drop of the diode 313.

The operation of the embodiment apparatus configured in this manner will be explained.

First, when the key switch 5 is closed when starting the engine, the power is transferred from the storage battery 4 to the key switch 5, the resistor 304, and the diode 3.
Since the base current is supplied to the transistor 302 through the transistor 14 and the transistor 302 becomes conductive, a field current flows from the storage battery 4 to the field coil 102 through the transistor 302, and a field magnetomotive force is generated.

When the engine is started in this state and the generator 1 is driven, an alternating current output is induced in the armature coil 101 according to its rotational speed, and this output voltage is full-wave rectified by the full-wave rectifier 2.

Here, if the rectified output voltage is below a predetermined value, the resistor 308
, 309, the voltage dividing point potential of the voltage dividing circuit is still low, so the zener diode 307 remains non-conducting, so that the output voltage of the generator 1 increases as the rotational speed increases. It is rising accordingly.

Thereafter, when the rotational speed of the generator 1 further increases and the output voltage exceeds a predetermined value, the potential of the voltage dividing point of the voltage dividing circuit also increases, and the zener diode 307 becomes conductive. A base current flows through the diode 307 to the transistor 305, making the transistor 305 conductive.

If this transistor 305 conducts, the transistor 3
02 becomes non-conductive, cutting off the field current of the field coil 102, and the output voltage of the generator 1 drops again.

- By repeating the above-described operations, the output voltage of the generator 1 is controlled to a predetermined value, and the storage battery 4 is charged to the predetermined value using this control voltage.

Here, when the transistor 305 is cut off, the energy stored in the negative feedback capacitor 310 is transferred to the diode 31.
3 prevents backflow, and almost all the energy is 11~
Since it is released to the base circuit of the transistor 305, the negative feedback effect increases.

In addition, when the transistor 305 becomes conductive, the diode 313 adds the forward voltage drop of the diode 314, which is equivalent to increasing the saturation voltage of the transistor 1 to transistor 305. It is inserted to compensate for this forward voltage drop since it becomes difficult to shut off.

Therefore, if a transistor with a large forward voltage drop between the base and emitter, such as a Darlington-connected transistor, is used in place of the transistor 302, the diode 314 can be omitted.

Furthermore, even if the field current is intermittent through a transistor that amplifies the output of the first transistor 302, the same effects as those described above can be obtained.

In addition, a positive feedback circuit (resistors 311, 306,
Even if the present invention is applied to a voltage regulation circuit that does not have a capacitor (312), it not only prevents malfunctions caused by external high-frequency noise, but also effectively corrects the substantial drop in the regulation voltage caused by current output ripple. It's something you get.

In the device of the present invention as described above, the capacitance of the negative feedback capacitor 310 and the The external size can be reduced, and it is inexpensive, reliable, and has excellent effects.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing a conventional device, and FIG. 2 is an electric circuit diagram showing an embodiment of this invention. In the figure, 1 is a generator, 101 is an armature coil, 102 is a field coil, 2 is a full-wave rectifier, 3 is a semiconductor voltage regulator,
301, 313, 314 are diodes, 302, 30
5 is a transistor, 303, 304, 306, 308,
309 and 311 are resistors, 307 is a Zener diode, and 310 and 312 are capacitors. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] An alternating current generator having an armature coil and a field coil, a rectifier that rectifies the alternating current output generated in the armature coil, a storage battery that is charged by the rectified output of the rectifier, and a rectified output of the storage battery or the alternating current output. a first transistor that intermittently controls the feeding current of the field coil to which power is supplied; the transistor is provided in a circuit that bypasses the base current of the transistor; the base current of the first transistor is intermittently controlled in accordance with the rectified output voltage; a negative feedback capacitor inserted between the collector and base of the second transistor; A semiconductor voltage regulator comprising a reverse current blocking diode connected between the base of the transistor and the base of the second transistor in the direction of conduction of the second transistor.