JPS6358028B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle charging device, and is intended to prevent malfunctions in the event of an abnormality.

The circuit configuration of the charging device shown in FIG. 1 has been proposed by the present inventors.

In FIG. 1, the power necessary for the operation of each circuit in the voltage regulator 2 is supplied from a terminal 204 through a power line 27 via a battery 3 and a key switch 4. If this terminal 204 is disconnected, the power source is battery 3 → key switch 4 → charge lamp 5 →
It is supplied through the path of terminal 205 → diode 255 in transistor 250 → power supply line 27. At this time, the voltage of the power line 27 is determined by the voltage regulator 2.
As the current consumed by each circuit in the circuit changes, the current flowing through the charge lamp 5 changes, and the voltage drop occurring across the charge lamp 5 also changes, making it extremely unstable. For example, it is clear that the voltage of the power supply line 27 is significantly different when the transistor 24 is conductive and when it is not conductive. If the voltage of the power supply line 27 becomes unstable in this way, each circuit in the voltage regulator 2 is likely to malfunction, and power generation control of the alternator 1 may become impossible, which is not preferable.

In order to eliminate the above-mentioned problems, each transistor 2501 shown in FIGS. 2, 3, and 4 is used instead of the transistor 250 in the configuration shown in FIG.
It is also possible to use 2502 and 2503. However, each of these has drawbacks as described below. First, the transistor 250 in FIG.
1, the current amplification factor is significantly smaller than that of the transistor 250, so a current amplification circuit with a larger amplification factor than the case where the transistor 250 is used is required in the power generation detection circuit 23. When the transistor 2502 shown in FIG. 3 is used, it is superior to the transistor 250 in terms of current amplification factor, but it tends to malfunction as it becomes conductive even with a small leakage current. Malfunctions due to this leakage current can be prevented to some extent by connecting an external resistor between the emitter terminal 256 and the base terminal 258. However, when transistor 2502 is non-conducting, transistor 2
Since a stable potential is not applied to the base terminal of the transistor 252 in the transistor 502, the reverse breakdown voltage between the collector and emitter of the transistor 252
It decreases compared to Transistor 2503 in FIG.
When using transistor 25, both the current amplification factor, malfunction due to leakage current, and breakdown voltage are
0, and unlike the case of the transistor 250, there is no diode 255, so the above-mentioned problem does not occur. However, transistor 25
In order to create a structure like 03 in one silicon chip, a more complicated process is required compared to the case of the transistor 250, or if it is manufactured in the same process as the transistor 250, the structure inside the transistor 2503 is required. In order to make the resistor 254 in the transistor 250 have the same resistance value as the resistor 254 in the transistor 250, a larger chip area is required.

The present invention has been made in order to eliminate the above-mentioned drawbacks.

The embodiment of the present invention shown in FIG. 6 will be specifically described below. Each circuit of the present invention is constructed with the intention of semiconductor integration. 1 is an alternating current generator equipped with a rectifier, 2 is a voltage regulator, and this voltage regulator 2 has a transistor 21 that controls the excitation current of the alternator 1, and a terminal that supplies the charging voltage to the battery 3 of the alternator 1. In addition to the voltage regulating circuit 22 which is detected at 201 and thereby controls the transistor 21, there is also a transistor 24 which constitutes second semiconductor switch means for driving the charge lamp 5 which constitutes the load.
, a transistor 25 serving as a first semiconductor switch means for driving the load 6, and a power generation detection circuit 2 that detects the generated voltage of the alternator 1 at a terminal 203 and thereby controls the transistors 24 and 25.
Equipped with 3. Diode 26 is a well-known freewheeling diode. The power line 27 is connected to the positive side of the battery 3 via the terminal 204 and the key switch 4.
Power is thereby supplied to each circuit included in the voltage regulator 2. As shown in FIG. 5, the transistor 25 includes two pnp type transistors 251 and 252 and one resistor 25 in one semiconductor chip.
3 and two transistors 251 and 2
52 is Darlington connected, and a resistor 253 is connected between the base and emitter of the transistor 251 in the previous stage. Resistor 28 is transistor 25
is connected between the emitter terminal 256 and base terminal 258 of.

Further, to describe in more detail the operation of the power generation detection circuit 23 and the transistors 24 and 25, the power generation detection circuit 23 detects the generated voltage of the alternator 1 at the terminal 203, and when the generated voltage is below a predetermined value, the 24 conductive, transistor 2
When the generated voltage exceeds a predetermined value, the transistor 24 is turned off and the transistor 25 is turned on. As a result, when the generated voltage of the alternator 1 is below a predetermined value, the charge lamp 5 is turned on and the load 6 is not driven, and when the generated voltage exceeds the predetermined value, the charge lamp 5 is turned off and the load 6 is turned on. Driven.

According to the above configuration, when the terminal 204 is disconnected, the power supply to the power line 27 is completely cut off, so the operation of each circuit in the voltage regulator 2 is reliably stopped, and the transistor 21 is in a non-conducting state. maintain.
Therefore, the AC generator 1 can reliably stop power generation. Furthermore, the resistor 28 can prevent malfunctions due to leakage current, and the base terminal of the transistor 252 in the transistor 25 is
Similarly, since the resistor 253 in the transistor 25 provides a stable potential even when the transistor is non-conductive, the reverse breakdown voltage between the collector and emitter does not decrease.

7 shows a specific example of the power generation detection circuit 23, and each terminal a, b, c, d, e in the figure corresponds to the symbol shown in the block 23 in FIG. In other words, the comparator 231 compares the smoothed voltage with the reference voltage, and when no power is being generated, the transistor 231
32 and 233 are configured to be turned off.

In addition, in the embodiment described above, the case where a pnp type transistor is used is described, but an npn type transistor is used.
The same thing can be said when using a type of transistor.

Here, as shown in FIG. 5, a resistor 25 is connected only between the emitter and base of the input stage transistor 251.
The point (a point described in the prior art) that the area of one semiconductor chip can be made significantly smaller than the circuit shown in FIG. 4 by connecting the circuits shown in FIG.

Normally, a PNP type Darlington transistor has an N-type diffusion region formed in a P-type silicon substrate, which serves as a common collector region of the input stage transistor and an output stage transistor, and an N-type diffusion region, which serves as the base region of each of the input stage and output stage transistors. A P-type diffusion region is formed inside an N-type diffusion region to serve as an emitter region of an input stage and an output stage. If you want to provide a resistance between the base and emitter of the input stage or output stage within the same chip of this Darlington transistor without increasing the manufacturing process, you can use a part of the N-type diffusion region that serves as the base region or the emitter region. The only way to do this is to pattern a part of the P-type diffusion region so that a predetermined resistance value can be obtained. (A resistor cannot be provided on the P-type silicon substrate portion, which will become the common collector region, because it is not possible to pattern a part of it separately and independently.) In addition, due to the characteristics required for transistors, the N-type silicon substrate portion, which will become the base region, cannot be provided with a resistor. The impurity concentration of the diffusion region is significantly lower (the specific resistance thereof is significantly higher) than that of the P-type diffusion region which becomes the emitter region. Therefore, if you try to form a resistor with the same resistance value in a part of the P-type diffusion region that will become the emitter region, the resistance will be significantly larger than when forming a resistor in a part of the N-type diffusion region that will become the base region. Pattern area is required.

Therefore, when providing a resistor, it is more advantageous in terms of chip area to pattern the resistor on a part of the N-type diffusion region that will serve as the base region, but if it is connected between the base and emitter of the output stage, Target N
The type diffusion region will be connected to the emitter of the output stage transistor, and a PN junction diode will be formed between it and the P type silicon substrate, i.e. the common collector of the Darlington transistor (this is the first
250 shown in the figure). As is clear from the above, like 2503 shown in Figure 4,
In order to provide a resistance between the base and emitter of the output stage transistor without forming a diode between the common collector and the emitter of the output stage transistor within the same chip of the Darlington transistor, it is necessary to This results in either forming a resistor in a portion or adding an additional process to form the resistor.

Further, in the embodiments described above, a case has been described in which a PNP type transistor is used as the first switching means, but the same can be said when an NPN type transistor is used.

The same thing can be said even if the charge lamp 5 serving as a load is another load such as a coil, a resistor, a light emitting diode, or the like.

As described above, in the present invention, two loads are connected in series to the battery, and these two loads are driven depending on whether the alternator is generating power or not. In order to perform contradictory driving such as driving the other load in the case of power generation, first and second semiconductor switch means are connected in series between the battery and the ground terminal. In a configuration in which the mutual connection points of the two semiconductor switch means and the mutual connection points of the two loads are connected, an input stage is provided in one semiconductor chip as the first semiconductor switch means connected to the battery side. By making a Darlington connection between the transistor and the output stage transistor, and by connecting a resistor only between the base and emitter of the input stage transistor, the first semiconductor switch means can prevent malfunctions due to current amplification factors, leakage currents, and breakdown voltages. , both the manufacturing process and the chip area can be made almost the same as those of the previous ones, and malfunctions will not occur if the connection between the load and the first semiconductor switch means is disconnected. This excellent effect can be obtained.

[Brief explanation of the drawing]

FIGS. 1 to 4 are electrical circuit diagrams showing examples proposed by the present inventors, and FIGS. 5, 6, and 7 are electrical circuit diagrams showing one embodiment of the present invention. . 1... AC generator, 2... Voltage regulator, 3...
battery, 5...charge lamp, 6...load,
22... Voltage adjustment circuit, 23... Power generation detection circuit,
24, 25...Transistor, 28...External resistor, 251, 252...Darlington configuration transistor, 253...Resistor.

Claims (1)

[Claims] 1. A power generation detection circuit that detects the power generation state of the generator and generates a signal in accordance with the power generation state, and a first semiconductor switch means and a second semiconductor that are connected in parallel to the battery via a key switch. a series circuit comprising switch means; and a load provided between one end of the key switch and a connection point of the first and second semiconductor switch means, and the first semiconductor switch means has a Darlington structure. It consists of an output stage transistor and an input stage transistor, and a resistor is provided only between the base and emitter of this input stage transistor, and the output stage, input stage transistor, and resistor are formed in one semiconductor chip, and the An external resistor is provided between the base side of the input stage transistor and the emitter side of the output stage transistor, and the first and second semiconductor switch means are driven in accordance with the signal from the power generation detection circuit. A vehicle charging device characterized by comprising: