JPH11204900A - Electronic circuit board device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent malfunction of a device, by surrounding a lead terminal for control of an integrated circuit element and a part of a printed pattern connected with the terminal, with a printed pattern connected with lead terminals relating to a power source. SOLUTION: A lead terminal A1 with which a driving transistor 19 is connected, and a printed pattern A2 for connecting the lead terminal A1 with a first current control resistor 16, are surrounded on an electronic circuit board, with a printed pattern B for protection which constitutes a power source line (+V). When water drops permeate in such a manner that the printed pattern A2 for connecting the lead terminal A1 of a driving transistor 19 with the first current control resistor 16 is covered, the lead terminal Al is connected with the power source line (+V) via the water drops, potential of the lead terminal A1 increases, and the driving transistor 19 is led to the direction of non-operation. As a result, an ignition current can be prevented from flowing in a detonator 6, i.e., action in the safety direction can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit in which a malfunction is not permitted, for example, in an occupant protection device used for protecting an occupant by inflating an airbag instantaneously in a collision accident of a vehicle or the like. The present invention relates to a substrate device.

[0002]

2. Description of the Related Art A conventional occupant protection system of this type will be described with reference to FIG. Reference numeral 1 denotes a vehicle-mounted battery, 2 denotes an ignition switch, and 3 denotes a DC / DC converter, which boosts the output voltage of the vehicle-mounted battery 1 and outputs the boosted voltage. Reference numeral 4 denotes a backup capacitor which is connected to the output of the DC / DC converter 3 and is charged by its boosted output. 6 is the primer,
Reference numeral 7 denotes a field effect switching transistor for drive control, which is connected in series to the primer 6 and connected to an output terminal of the DC / DC converter 3. Reference numeral 8 denotes a first acceleration sensor, and 9 denotes a second acceleration sensor which has the same performance as the first acceleration sensor 8 and detects acceleration in the same direction.

A microcomputer 10 includes a comparison circuit 11, a collision determination circuit 12, a switching circuit 13, and the like. The comparison circuit 11 compares the magnitude of the acceleration signal supplied from the second acceleration sensor 9 with a reference value. If the reference value is exceeded, it is determined that a collision has occurred and the collision determination circuit 1
2 is supplied with a switch signal. The collision determination circuit 12 receives the acceleration signal from the first acceleration sensor 8 and the switch signal from the comparison circuit 11 and determines that the collision is a serious collision, and determines each of the switching circuit 13, the field-effect switching transistor 7, and the drive control transistor 14 To supply a high level signal to turn on each of them.

The switching circuit 13 is normally connected as shown by solid lines with switching contacts and outputs a high-level signal. In the event of a collision, the switching circuit 13 switches the switching contact from the connection shown by the solid line to the connection shown by the broken line, and outputs a low-level signal.

Reference numeral 15 denotes a current limiting circuit, and a constant voltage circuit 18,
Drive transistor 19, current detection resistor 20, amplifier circuit 2
1, a driving transistor 23, a bias resistor 22, and the like. The constant voltage circuit 18 is a first current controlling resistor 16 of first and second current controlling resistors 16, 17, which will be described later.
The potential of the non-ground side terminal is kept constant, and the current value at that time is obtained regardless of whether the connection point of the first and second current control resistors 16 and 17 is clamped by the power supply or grounded. Is detected by the current detection resistor 20 with high accuracy. The detected current value is amplified at a predetermined amplification rate by the amplifier circuit 21 via the signal line A, and the amplified current value flows between the collector and the emitter of the driving transistor 23.

A drive control transistor 14 is connected to the signal line A to the amplifier circuit 21. When the drive control transistor 14 is off, the current detection resistor 20
Is amplified by the amplifier circuit 21 at a predetermined amplification factor, and the drive transistor 23 is turned on. On the other hand, when the drive control transistor 14 is on,
Since the input terminal of the amplifier circuit 21, that is, the signal line A is grounded, even if the current detection signal is amplified and supplied at a predetermined amplification rate via the signal line A, the drive transistor 23 is not turned on.

Next, the operation of the above configuration will be described. (1) When the collision judging circuit 12 does not judge a collision The contact 13a in the switching circuit 13 is held in the connection relationship shown by the solid line, and the first and second current control resistors 16, 1
Since the potential at the connection point 7 is clamped to the power supply voltage (+ V), only a small current flows through the current detection resistor 20, and the primer 6 is not ignited.

(2) When the collision determination circuit 12 determines that a collision has occurred: The contact 13a in the switching circuit 13 is switched to the connection shown by the broken line and held by the high level signal from the collision determination circuit 12, and the first Since the connection point between the first and second current control resistors 16 and 17 is grounded, the drive transistor 19 conducts and a large amount of current flows through the current detection resistor 20 and the second current control resistor 16, and the current is detected by the current detection. It is detected by the resistor 20 and supplied to the amplifier circuit 21. At this time, since the drive control transistor 14 is turned off and the switching transistor 7 is turned on, the voltage supplied by the signal line A is amplified by the amplifier circuit 21 at a predetermined amplification factor. The drive transistor 23 is turned on, and an ignition current is supplied to the primer 6.

[0009]

However, many semiconductor circuit elements including microcomputers have recently been increasingly integrated or miniaturized, and the intervals at which lead terminals such as input / output terminals and power supply terminals are arranged are arranged. In the above-described electronic circuit board device, water invades the inside of the case or the like, turning on the transistors 7 and 23 and so on, and supplying an ignition current to the primer 6 so that the There was a problem that was misdeployed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide an apparatus which is less likely to malfunction by devising a print pattern.

[0011]

According to a first aspect of the present invention, a plurality of lead terminals are arranged adjacent to each other, and a control lead terminal and a power supply related lead terminal are adjacent to each other. An electronic circuit board device for soldering integrated circuit elements arranged in a pattern to lands of a printed pattern and electrically connecting the circuit elements by the printed pattern, wherein the control lead terminals of the integrated circuit elements and the prints connected thereto are provided. A part of the pattern is surrounded by a printed pattern connected to the power-related lead terminals.

According to a second aspect of the present invention, there is provided an electronic circuit board device in which a semiconductor circuit element having a plurality of lead terminals and another circuit element are electrically connected by a printed pattern. The printed pattern connecting to the circuit element is surrounded by a printed pattern related to the power supply.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Embodiment 1 according to the present invention will be described below with reference to FIGS. 1 to 3, but detailed description of the same or equivalent components already described with reference to FIG. 4 will be omitted. Only different components will be described. That is, as shown in FIG. 2, the lead terminal A1 to which the drive transistor 19 forming the current limiting circuit 15 is connected,
A printed pattern A2 for connection between the lead terminal A1 and the first current controlling resistor 16 is surrounded on the electronic circuit board by a protective printed pattern B constituting a power supply line (+ V). Penetrates so as to cover the connection printed pattern A2 between the lead terminal A1 and the first current control resistor 16, the lead terminal A1 is connected to the power supply line (+ V) via the water droplet, and the potential of the lead terminal A1 is reduced. As a result, the driving transistor 19 rises and is guided in a non-operating direction, so that the ignition current does not flow through the primer 6, that is, it acts in a safe direction.

Next, as shown in FIG. 3, the lead terminal C1 of the switching transistor 7 is connected to the lead terminal C1.
A ground line C3 is provided on the electronic circuit board such that the protective resistor D and the bias resistor 30 and the connection print pattern C2 are surrounded by the protection print pattern D. As a result, water drops are generated in the switching transistor 7.
Lead terminal C1, lead terminal C1 and bias resistor 30
Penetrating so as to cover the connection print pattern C2,
The lead terminal C1 is connected to the earth line C3 via the water drop, and the potential of the lead terminal C1 is reduced to guide the switching transistor 7 in a non-operating direction, so that the ignition current does not flow through the primer 6; Act on.

[0015]

As described above, according to the first and second aspects of the present invention, even when water drops enter, an important part in the operation of the circuit is that the potential rises so that the output operates in a safe direction. Or descend, so that an effect of being able to use it with peace of mind is obtained.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of an occupant protection device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram for explaining a main part of FIG. 1;

FIG. 3 is a circuit diagram for explaining a main part of FIG. 1;

FIG. 4 is a circuit block diagram of a conventional occupant protection device.

[Explanation of symbols]

 7 Switching transistor 15 Current limiting circuit 16 Current control resistor 19 Drive transistor 30 Bias resistor A1, C1 Lead terminal A2, C2 Connection print pattern B Protection print pattern C3 Earth line

Claims (2)

[Claims] An integrated circuit element in which a plurality of lead terminals are arranged adjacent to each other, and of which a control lead terminal and a power supply related lead terminal are arranged adjacent to each other, is soldered to a land of a printed pattern. An electronic circuit board device for electrically connecting circuit elements by a printed pattern, wherein the control lead terminal of the integrated circuit element and a part of a printed pattern connected to the control lead terminal are formed by a printed pattern connected to the power-related lead terminal. An electronic circuit board device, which is enclosed. 2. An electronic circuit board device in which a semiconductor circuit element having a plurality of lead terminals and another circuit element are electrically connected by a printed pattern, wherein a control lead terminal of the semiconductor circuit element and another circuit element are connected to each other. An electronic circuit board device characterized in that a printed pattern connecting the two is surrounded by a printed pattern related to a power supply.