JPS593170A - Semiconductor ignition device - 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 a semiconductor ignition device for an internal combustion engine.

As shown in FIG. 1, a conventional semiconductor ignition device turns on and off a power transistor 4 by applying an AC voltage generated from an electromagnetic pickup coil l to a control circuit 3 via an input circuit 2 in synchronization with engine rotation. make it work,
The primary current of the ignition coil 5 flowing from the power source 6 is intermittent to generate a high voltage on the secondary side of the ignition coil 5, and this high voltage causes a spark to be generated in the ignition gragua to discharge and ignite the fuel mixture sword. There is. In this case, the input circuit 2 includes transistors Q□, Q2゜Q3, as shown in FIG.
．． Q4. A differential amplifier 8 consisting of a current source ■, an emitter resistor R, and a pace resistor R2, R3.
Resistors R, , R that give the same bias voltage to both terminals of
5, an electromagnetic pickup coil 1 is connected between a pair of input terminals of a differential amplifier 8, and when a voltage of the polarity shown in the diagram is generated in the electromagnetic pickup coil 5, an ignition signal is generated from the output terminal OUT. It is supposed to be done. Further, the control port 183 receives the wl source voltage V. The spark generated in the spark plug 7 is stabilized by controlling the energization time of the primary current of the ignition coil 5 in response to fluctuations in the spark plug 7. As a result, the resistor 9 that limits the current of the ignition coil 5 is no longer necessary, and the ignition coil 5 itself is also downsized due to the elimination of the need for the resistor 9 and more efficient energization time control. It is lighter overall. In addition,
10 is an ignition switch.

However, in such a conventional semiconductor ignition device, when the ignition key switch 10 is turned on, the power supply voltage V is applied to the ignition coil 5. is applied, but the engine is stopped and there is no input signal from the electromagnetic pickup coil (one pick-up coil), and there is no need to energize the ignition coil 5. Transistor 4 is turned on continuously, a Tue:! There was a risk that the primary winding of the coil 5 would be continuously energized by an overcurrent, causing heat generation and destruction of the ignition coil 5 or the control circuits 3, 7 (warp engine nut 4, etc.) in the preceding stage. This is because the differential amplifier 8 operates very unstable and there is a possibility that a signal that turns on the power amplifier 4 may be generated from the output terminal 0[JT of the differential amplifier 8.

Therefore, an object of the present invention is to provide a semiconductor ignition device that can prevent the ignition coil and the like from being destroyed by heat.

This invention applies a constant bias voltage to a pair of input terminals of a differential amplifier, and also applies a predetermined offset voltage between the pair of input terminals, so that when the input signal is Ov, the differential amplifier and the power transistor are switched. It is configured to generate a signal that always turns it off. The offset voltage between a pair of input terminals is caused by the differential amplifier itself producing an offset of about 0.5 to 2 mV in a well-designed integrated circuit due to variations in the amplification factor and base resistance of the differential amplifier. The value should be small enough to extinguish the ignition, and it is better to make it as small as possible in terms of ignition timing.

A first embodiment of this invention is shown in FIG. That is, this semiconductor ignition device has a resistor R6 and a diode D in the power supply 6.
Connect the series circuit of □ and resistor Rヮ, connect the connection point of the diode wire and resistor R7 to the non-inverting input terminal (signal input terminal) of the differential amplifier 8 via the electromagnetic pickup coil 1, and Connect a series circuit of resistors R9 and R8 in parallel to the drawer, connect the connection point of resistors R9 and R8 to the inverting input terminal (reference input terminal) of the differential amplifier 8, and connect the resistor R7 to the υ differential amplifier 8.
A bias voltage is applied to the non-inverting input terminal and the inverting input terminal of the diode, and the forward voltage drop of about 0.7V of the diode drawer is divided by resistors R8 and R8, and the offset voltage is higher at the inverting input terminal. The signal is applied between the non-inverting input terminal and the inverting input terminal of the dynamic amplifier 8. In this case, the ratio of resistors R8 and R8 is 1
When the resistance value is about 100 υ, when it is integrated into an integrated circuit, the minimum resistance value of the integrated circuit is about 100Ω, and the resistance value 100 times this value is about IOKΩ.

As a result of this configuration, when the input signal from the electromagnetic pickup coil 1 is Ov, the voltage at the inverting input terminal is always higher, and the output of the differential amplifier 8 always turns off the power twangister 4. , continuous energization of the ignition coil 5 is prevented, and destruction of the ignition coil etc. due to heat generation can be prevented.

A second embodiment of this invention is shown in Figure @4. That is, in this semiconductor ignition device, the power supply 6 includes a resistor R1o.

Connect the series circuit of R□, and connect the resistor R. , R, are connected to the non-inverting input terminal of the differential amplifier 8 via the electromagnetic pickup coil 1, and a resistor R□ is connected. K resistance R engineering.

Connect the series circuits of R and R in parallel, and connect the resistors R and 3. Connect the connection point of R□2 to the inverting input terminal of the differential amplifier 8, and apply an input bias voltage to the differential amplifier 8 through the resistor R. Voltage of resistor R 3. The offset voltage is applied between both input terminals of the differential amplifier 80, with the inverting input terminal having a higher offset voltage. The effect is similar to the previous embodiment.

A third embodiment of the present invention is shown in FIG. .

Connect the series circuit of the resistor R and the diode D2, connect the connection point of the resistor R and the diode D2 to the non-inverting input terminal of the differential amplifier 8 via the electromagnetic pick-up coil 1, and connect the resistor R to the non-inverting input terminal of the differential amplifier 8. Resistance R work 7. R-engineer. Connect the series circuits of 7 in parallel and connect the resistor R.7. R-engineer. The connection point of the differential amplifier 8 is connected to the inverting input terminal of the differential amplifier 8, and the diode D2 connects the connection point of the differential amplifier 8 to the inverting input terminal of the differential amplifier 8.
Apply an input bias voltage to the resistor R□5, and change the voltage across the resistor R
Engineering 7. R-engineer. The offset voltage is divided by the differential amplifier 8.
is giving to The effect is similar to the previous embodiment.

A fourth embodiment of the invention is shown in FIG. That is, this semiconductor ignition device has a resistor R in the power supply 6. .

R engineering 9. Connect the series circuit of R20 and connect the resistor R9. R2
Connect the connection point of 0 to the non-inverting input terminal of the differential amplifier 8 via the electromagnetic pickup coil 1, and connect the resistor R2 to the resistor R9.
2. Connect the series circuit of R21 in parallel, and connect the resistors R2Q and R2
Connect the connection point □ to the inverting input terminal of the differential amplifier 8, apply an input bias voltage through the resistor R2o, and connect the resistor R.

The voltage is divided by resistors R22 and R2□ to provide an offset voltage.

This embodiment, like the previous embodiment, prevents continuous energization of the ignition coil 5 and prevents the ignition coil 5 and the like from being destroyed by heat. Also, the voltage obtained by subtracting the bias voltage from the power supply voltage is applied to the resistor R□8. Since the voltage of resistor R is further divided by resistor R22 and R2□ to create an offset voltage, it is possible to reduce the number of resistors with large resistance values, and when it is integrated into an integrated circuit. Since the ratio occupied by the resistor is small, the mask design of the integrated circuit is easier than in the first and second embodiments. In addition, in recent years, the engine compartments of automobiles have become smaller, the distance between noise sources and other electronic components has become shorter, and the proportion of noise received by electronic components has increased.
Since the input bias is applied at 0, the same level of noise enters both terminals and is canceled within the differential amplifier 8, thereby reducing the influence of noise. Note that when the input bias voltage is applied by the diode D2 as in the third embodiment, the noise entering the inverting input terminal is smaller than the noise entering the non-inverting input terminal, and is no longer canceled and the differential amplifier 8 The noise output from is relatively large. In addition, the diode D2 causes a phase shift between the noise entering the non-inverting input terminal and the noise entering the inverting input terminal, and the noise is affected more greatly than in the case of FIG.

FIG. 7(2), Q3) is a waveform diagram showing this, and S and S in the same drawing indicate noise entering the non-inverting input terminal and the inverting input terminal of the differential amplifier 8 in the case of FIG. 5.

Is your job a noise? , indicates the level difference between S- and 0 is noise?
, S-. , also in the same figure)? ,
S- indicates the noise in the case of Fig. 6, and vN indicates the noise s”
, s-.

The electromagnetic pickup coil 1 is connected directly to the signal input terminal of the differential amplifier 8 or via a resistor, a diode, etc., and the connection point of the resistors R20 and R22 is also connected directly to the inverting input terminal of the differential amplifier 80. Connected via etc.

As described above, the semiconductor ignition device of the present invention includes an electromagnetic pickup coil that generates an alternating current voltage in synchronization with the rotation of the engine, one end of the electromagnetic pickup coil connected to the signal input terminal, and the electromagnetic pickup coil. A differential amplifier whose other end is connected to the reference input terminal, a power transistor that turns on and off in response to the output of this differential amplifier, and a primary current that is intermittent in response to the on and off of this power transistor, resulting in a high voltage on the secondary side. an ignition coil that generates a voltage; a spark plug that generates a spark by a secondary voltage of the ignition coil; a bias applying means that applies a bias voltage l to a signal input terminal and a reference input terminal of the differential amplifier; an offset voltage that applies a predetermined offset voltage between a signal input terminal and a reference input terminal of a dynamic amplifier to cause the differential amplifier to generate an output for always turning off the power transistor when the electromagnetic pickup coil has zero output; Since it is provided with a applying means, it is effective in preventing heat generation destruction of the ignition coil and the like.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional semiconductor ignition device, □ Fig. 2 is a specific circuit diagram of its main parts, Fig. 3 is a main part circuit diagram of the first embodiment of the present invention, and Fig. 4 is a circuit diagram of the main parts of the present invention. 5 is a circuit diagram of the main part of the second embodiment of the present invention, FIG. 6 is a circuit diagram of the main part of the fourth embodiment of the invention, and FIG. 7 is a circuit diagram of the main part of the fourth embodiment of the invention. , (B) are waveform diagrams for explaining the effect. 1... Electromagnetic pickup coil, 2... Input circuit. 3...ftrt control circuit, 4...power transistor, 5...ignition coil, 6...power supply, 7...spark plug, 8...differential amplifier, R engineering, ~R22...・Resistance Figure 1 Figure 2 Figure 7

Claims (1)

[Claims] An electromagnetic pickup coil that generates an alternating current voltage in synchronization with engine rotation, one end of which is connected to a signal input terminal, and the other end of this electromagnetic pickup coil is connected to a reference input terminal. and a power transistor that turns on and off in response to the output of this differential amplifier. An ignition coil that generates a high voltage on the secondary side by intermittent primary current in response to the on/off of this power transistor, a spark plug that generates a spark by the secondary voltage of this ignition coil, and a signal of the differential amplifier. bias applying means for applying a bias voltage to an input terminal and a reference input terminal, and a predetermined offset voltage between a signal input terminal and a reference input terminal of the differential amplifier to activate the power transistor when the electromagnetic pickup coil has a zero output; A semiconductor ignition device comprising an offset voltage applying means for causing the differential amplifier to generate an output to always turn off the semiconductor ignition device.