JPS6032525A - Input circuit for electronic controller for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in input circuits for electronic control devices employed in vehicles such as automobiles, industrial vehicles, and mobile agricultural machinery.

Conventionally, as shown in FIG. 1, this type of input circuit includes, for example, a resistor 61 and a complementary metal oxide film semiconductor integrated circuit 62 (hereinafter referred to as CMO8
circuit 62], microcomputer 20 and C
A stabilized power supply circuit 66 that is connected to the MO8 circuit 62 and a resistor 6 that connects the detection switch 10 to the stabilized power supply circuit 66.
There is one that consists of 4.

Therefore, in such a configuration, the microcomputer 20 and the CItll OS circuit 62 receive the constant voltage (+5V) from the stabilized power supply circuit 66 that is generated by being supplied with power from the battery B when the operation switch SW is closed. When it is in the operating state, the CMO8 is
The CMO8 circuit 62 is connected to the detection switch 1 through a conductor and/or resistor 61 connecting the circuit 62 to the stabilized power supply circuit 66.
By reducing pulse-less high voltage noise such as engine ignition noise and alternator noise of the vehicle that tends to be carried by the conductor connected to However, in such a configuration, the detection switch If the number of 10 increases with the sheet resistance 31.34, then the individual detection switch 1
Even if the current consumption of the stabilized power supply circuit 36 is small, the current consumption of the stabilized power supply circuit 36 increases, and as a result, the power capacity of the stabilized power supply circuit 66 must be increased, resulting in an increase in the size and cost of the stabilized power supply circuit 66. . In addition, as each detection switch 10 opens and closes, the constant voltage from the stabilized power supply circuit 66 fluctuates in accordance with fluctuations in its current consumption, causing the microcomputer 20 to
And proper operation of the CMO8 circuit 62 will be hindered.

In order to prevent this, for example, as shown in FIG. It is connected to each detection switch 1D via the operation switch SW and each transistor circuit 66, and relies on the stabilized power supply circuit 66 to supply power to each detection switch 10 while preventing the latch-up phenomenon of the CMOS circuit 62 from occurring. There is a system that relies on battery B to prevent voltage fluctuations in the stabilized power supply circuit 66. However, in such a configuration,
The larger the number of detection switches 10, the more transistor circuits 35.
The logarithm of 36 also increases, and as a result, the number of parts increases, resulting in a high cost.

In addition, as shown in FIG. 6, in the input circuit shown in FIG.
It is also possible to connect directly to the
Since power is supplied to each detection switch 1o in the same manner as the input circuit shown in FIG. 2, depending on the battery B without depending on the stabilized power supply circuit 66, the stabilized power supply circuit
Although the voltage fluctuation of 3 can be prevented, the 4
The high-energy, high-voltage noise on the line becomes very high, causing a latch-up phenomenon in the CMO8 circuit 62. Furthermore, since the voltage applied from the battery B to the CMO8 circuit 62 via each resistor 61 when each detection switch 10 is opened is higher than the constant voltage from the stabilized power supply circuit 63 applied to this CMO8 circuit 32, the CMO
This causes a latch-up phenomenon in the 8 circuit 62 and performance deterioration of each of the 414 elements in the CMOS circuit 62.

The present invention was made in response to such problems,
The purpose of this is to construct the input circuit applied to the microcomputer and multiple detectors of the vehicle's electronic control unit at low cost with a small number of parts, and to suppress fluctuations in the constant voltage of the stabilized power supply circuit. The object of the present invention is to ensure that the occurrence of latch-up phenomenon in the 0M08 circuit can always be prevented.

In order to achieve such an object, the present invention provides a vehicle electronic control device including a microcomputer and at least first and second detectors.
When the 0M08 circuit connected to the microcomputer is supplied with a DC' voltage from the DC power source, each allowable power supply voltage of the microcomputer and the 0M08 circuit is generated as a first constant voltage, and the microcomputer and the 0M08 circuit are connected to each other.
a first stabilizing power supply circuit applied to each power supply terminal of the MO8 circuit; and a second stabilizing power supply circuit that generates a second constant voltage lower than the DC voltage and higher than the first constant voltage when DC voltage is applied from the DC power supply. a power supply circuit, this second stabilized power supply circuit,
The first detector and the C! The first connecting conductor is interposed in a first connecting conductor connected between the first signal input terminals of the Mos circuit to allow current to be applied from the second stabilized power supply circuit to the first detector. a first resistor circuit that divides the second constant voltage into a voltage lower than the first constant voltage and applies the divided voltage to the first human power terminal of the CMOS circuit while reducing high voltage noise associated with the CMOS circuit; 0M08 circuit is interposed in a second connecting conductor connected between the stabilized power supply circuit, the second detector, and the second signal input terminal of the 0M08 circuit, and is connected to the second stabilized power supply circuit from the second stabilized power supply circuit to the second detector. The second constant voltage of the 0M08 circuit is divided by dividing the second constant voltage to a voltage lower than the first constant voltage while allowing the current to be applied and reducing high voltage noise on the second connecting conductor. The second resistor circuit is provided to provide power to the human power terminal.

By configuring the present invention in this way, the second stabilized power supply circuit is configured to reduce the amount of high energy that rides on the connecting conductor with the DC'' power source when converting the DC voltage to the second constant voltage. the first and second resistor circuits reduce high voltage noise of low energy riding on the first and second connecting conductors, respectively; The voltage applied to the first and second input terminals of the 0M08 circuit when the detector is not activated is set to the first constant voltage applied to the power supply terminal of the CMOS circuit.
IIV.

Since the voltage is lowered below the voltage, it is possible to reliably prevent the latch-up phenomenon of the 0M08 circuit and the performance deterioration of the CMO8 circuit configuration. In such a case, since the 0M08 circuit receives the first constant voltage from the first stabilized power supply circuit that is different from the second stabilized power supply circuit that is the power supply source to each of the detectors, Even if a fluctuation occurs in the outflow current from the second stabilized power supply due to the operation of each detector, the first constant voltage from the first stabilized power supply circuit does not fluctuate, and therefore the 0M08 circuit can always perform the level conversion function of the input signal under a stable constant voltage. Furthermore, in the present invention, the second stabilized power supply circuit and each resistance circuit can be constructed relatively easily, so this type of input circuit becomes inexpensive.

Hereinafter, a simple embodiment of the present invention will be explained with reference to the drawings.
The figure shows an example in which the input circuit according to the present invention is applied to a microcomputer 4° and a plurality of detection switches el + "2 + ..., sn that constitute a vehicle electronic control device. Input circuit The main stabilized power supply circuit 50 is equipped with a main stabilized power supply circuit 50, an auxiliary stabilized power supply circuit 60, and a CMO8 circuit 70. It is connected to the positive side terminal, receives DC voltage (+12■) from battery B when ignition switch G is closed, and generates a highly stable predetermined constant voltage from its output terminal. It is applied to each power supply terminal of the CMO8 circuit 70. This means that the microcomputer 40 and the CMOS circuit 70 receive a constant voltage from the main stabilized power supply circuit 50 to their respective power supply terminals and are put into operation. In such a case, the constant voltage from the main stabilized power supply circuit 50 is connected to the microcomputer 40 and the CMOB.
Considering each allowable power supply voltage of the circuit 70, it is +5■. Note that the CMO8 circuit 70 is connected at its output terminal to the input terminal of the microfusi computer 40.

Auxiliary stabilizing power supply circuit 601d, power transistor 61
This power transistor 61 has a collector connected to the battery B via the ignition switch 10.
It is connected to the positive side terminal of , and is grounded via a Zener diode 62 at its pace. The Zener diode 62 has a Zener voltage Z (+5V to +12V), and its cathode connected to the base of the power transistor 61 is connected to the collector of the power transistor 61 via a resistor 66. When the ignition switch 1G is closed, the Zener diode 62 receives a DC voltage from the battery B through the resistor 66, generates a Zener voltage 2, and makes the power transistor 61 conductive. This means that the power transistor 61 generates the Zener voltage 2 as a constant voltage from the die terminal (that is, the output terminal of the stabilized power supply circuit 60) due to its conduction. In such a case, high voltage noise having high energy from battery B on the connecting conductor between battery B and stabilized power supply circuit 60 is reduced by the cooperative action of power transistor 61, Zener diode 62, and resistor 66. Both capacitors 64 and 65 together form a closed circuit with the batch IJ 13 when the ignition switch G is closed, and absorb high frequency noise riding on the connecting conductor of this closed circuit.

One end of the resistor a1 is connected to the output terminal of the stabilized power supply circuit 60, and the other end is connected to the output terminal of the stabilizing power supply circuit 60.
When the detection switch θ1 is closed, the current flowing into the detection switch sl from the stabilized power supply circuit 60 based on its constant voltage is limited to a permissible value or less, and the resistor a2 is grounded at one end. It is connected to the output terminal of the stabilized power supply circuit 60, and is grounded at the other end via the detection switch s2. limit the current to below the allowable value, and resistor a.
n is connected to the output terminal of the stabilized power supply circuit 60 at one end, and grounded at the other end via the detection switch sn, so that when the detection switch Sn is closed, the stabilized power supply circuit is connected to the detection switch Sn. The current flowing from 60 against the constant voltage is limited to a permissible value or less.

The resistor b1 has one end connected to the resistor a1 and the detection switch s.
1, and the other end thereof is connected to the first input terminal of the CMO8 circuit 70, and rides on the connecting conductor between the detection switch S1 and the first input terminal of the CMOB circuit 70. C caused by pulsed high voltage noise such as vehicle engine ignition noise and alternator noise
To reduce the current flowing into the MO8 circuit 70, the resistor b2
One end thereof is connected to the common connection end of the resistor a2 and the detection unit S2, and the other end is connected to the CMO8 circuit 7.
0 is connected to the second input terminal of the detection Nuinoch S2 and C
The connection groove and the resistor bn between the second input terminal of the MO8 circuit 70 are connected at one end to the common connection end of the resistor an and the detection switch sn, and at the other end to the CMO
The detection switch sn and the resistor C of the CMO8 circuit 7-0 are connected to the n-th input terminal of the CMO8 circuit 70, and the first terminal of the CMO8 circuit 7o is connected to the nth terminal of the CMO8 circuit 70, and the resistor C of the CMO8 circuit 7-0 is grounded at one end and resistor C is connected to the nth terminal of the CMO8 circuit 70. The resistor c2 is connected to the connection end with the input terminal, divides the constant voltage from the stabilized power supply circuit 60 in cooperation with the resistor b1, and applies this divided voltage to the first input terminal of the CMOB circuit 7o. It is grounded at one end and connected to the second input terminal of the CMO8 circuit 7o of the resistor b2 at the other end, and divides the constant voltage from the stabilized power supply circuit 60 in cooperation with the resistor b2. The divided voltage of this pressure is C
It is applied to the second input terminal of the MO8 circuit 7o, and...
The resistor cn is grounded at one end and connected to the n-th input terminal of the CMO8 circuit 70 of the resistor bn at the other end, so that the constant voltage from the stabilized power supply circuit 60 is connected to the resistor bn. The voltage is divided by collaboration and this divided voltage is transferred to the CMO.
8 to the n-th input terminal of the circuit 70. When darning,
1 of the CMOB circuit 70. Second. . . ., the divided voltages applied to the n-th input terminals are applied to each detection switch S1.
+...+ CMO8 circuit 70 when Sn is open
The input voltage of the CMO8 circuit 700A can be determined as high level when the power supply voltage (5■) or less is higher than the input voltage (for example, 4V) (that is, the input can be determined as high level when the CMO8 circuit 70 does not cause latch-up phenomenon). value) so that the resistance value of each resistor c]+...+ cn is equal to each resistor al+
a2+ ...+ resistance value of an and each resistance bl +
b2 + . . . are determined in relation to the resistance value of bn.

In the present embodiment configured as described above, when the vehicle is placed in a running state by closing the ignition switch G, the ignition system and other various systems of the vehicle become operational, and the main stabilizing power supply circuit 50 becomes regulated. A voltage is generated and applied to each power supply terminal of the microcomputer 4o and the CMOB circuit 70 to put them into operation, and the auxiliary stabilizing power supply circuit 60 generates a constant voltage to connect each resistor al + C2+'',
+ “n respectively through each detection switch” 1+ 82+
・−・・+”n and each resistor bI + b2 + ・・
・, attached to bn.

Then, the constant voltage from the auxiliary stabilizing power supply circuit 60...
, is applied to the n-th input terminal. In such a case, CMO
The first .S circuit 70. The divided voltages applied to the second, +, and nth input terminals are not higher than the constant voltage from the main stabilized power supply circuit 50 applied to the power supply terminal of the CMO8 circuit 70, so the CMOS circuit 70 does not cause a latch-up phenomenon due to the divided voltage.

Furthermore, even if high voltage noise with high energy from batch IJ B is placed on the connecting conductor between battery B and auxiliary stabilizing power supply circuit 6o, this high voltage noise will be transmitted to power transistor 61 of auxiliary stabilizing power supply circuit 6o. , the Zener diode 62 and the resistor 66 cooperate to reduce the high voltage noise, so that the thus reduced high voltage noise is applied to each resistor bI + b2 together with the constant voltage from the auxiliary stabilizing power supply circuit 60.
+..., bn, the first . 2nd degree..., the voltage applied to the nth input terminal is
Due to the action of each resistor b1゜b2 + ``' + bn,
G! The constant voltage applied to the power terminal of the MO8 circuit 70 will never be higher than the constant voltage applied to the power terminal of the MO8 circuit 70, and as a result, the 0M08 circuit 70 will
No latch-up phenomenon occurs due to the influence of high voltage noise from J13. In addition, each detection switch I'
ll.

``'ij + '''+ Sn to the first of the CMO8 circuit 70
．． Even if the above-mentioned high voltage noise with low energy is placed on each connecting conductor wire connected to the 2nd..., nth input terminal, these high voltage noises will be absorbed by each resistor bl+b2+
..., bn, so that the QMOS circuit 70 does not cause a latch-up phenomenon.

This is true even when high voltage noise with low energy, suppressed high voltage noise with high energy, and the divided voltage of each resistor CI + C2+ . . . or cn are superimposed together. It's a trench, each detected Nuinoch"1
Even if there is a large fluctuation in the outflow current from the stabilized power supply circuit 60 due to the opening/closing operation of r "2 r...l" Jl, the microcomputer 40 and the CMOB circuit 70
Since both are supplied with power from the main regulated power supply circuit 50 that is separate from the auxiliary regulated power supply circuit 60, the main regulated power supply circuit 50
The constant voltage from the input signal does not fluctuate due to insufficient capacity, and the microcomputer 40 and the CMO-S circuit 70 can always maintain proper input signal level conversion operating conditions. In addition, open connection 4 between battery B and auxiliary stabilizing power supply circuit 6Q
Even if there is high frequency noise on the line, the capacitors 64 and 65 will absorb the high frequency noise, so C! MOE1 circuit 7
0 latch-up phenomenon will not occur.

Further, in implementing the present invention, for example, each resistor C1
+ C2+ ..., co is grounded at one end, and each pair of resistors '1+bI :'2 at each other end.
+ b2; ”・; an+ bn can be connected to the common connection end to achieve the same effect as in the above embodiment.

[Brief explanation of drawings]

1 to 6 are block diagrams of conventional input circuits employed in a vehicle electronic control device, and FIG. 4 is a block diagram not showing the input circuit according to the present invention. Explanation of symbols 40...Microcomputer, 5D...FI:,
Stabilized power supply @J path, 60...Auxiliary stabilized power supply circuit, 7
0...0M08 circuit, B...battery, 01~al
l+b, ~bn, C1Cn...resistance, mouth, ~8n/detection switch. Applicant Nippondenso Co., Ltd. Agent Patent Attorney Teru Hase −

Claims (1)

[Claims] In a vehicle electronic control device comprising a microcomputer and at least first and second detectors, a C M'OS circuit connected to the microcomputer, and a C M'OS circuit connected to the microcomputer, Each allowable power supply voltage of the computer and 0M03 circuit is generated as the first constant voltage, and the microcomputer and CMOS
a first stabilized power supply circuit applied to each power supply terminal of the circuit; and a second stabilized power supply that generates a second constant voltage lower than the DC voltage and higher than the first constant voltage when DC voltage is applied from the DC power supply. circuit, and a first connecting conductor connected between the second regulated power supply circuit, the first detector, and the first signal input terminal of the 0M08 circuit, so that the second regulated power supply circuit is connected to the second regulated power supply circuit. The 0M08 circuit divides the second constant voltage to a voltage lower than the first constant voltage while allowing current to be applied to the first detector and reducing high voltage noise Z on the first connecting conductor. interposed in a second connecting conductor connected between a first resistance circuit applied to a first input terminal of the circuit, and a second signal input terminal of the second stabilized power supply circuit, the second detector, and the 0M08 circuit. to allow a 7E current to be applied from the second stabilized power supply circuit to the second detector and to reduce high voltage noise on the second connecting conductor while changing the second constant voltage to the first constant voltage. A second voltage divided to a much lower voltage and applied to the second input terminal of the 0M08 circuit.
An input circuit for a vehicle electronic control device, characterized in that it is provided with a resistance circuit.