JPH09280147A - Internal combustion engine ignition circuit device and internal combustion engine ignition semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the vibration of a collector voltage by providing a coil current detecting part and a circuit for lowering a gate voltage in a MOS gate structure transistor and adding to a gate terminal the voltage of a current flowing from a main terminal into the gate terminal when a main terminal voltage is higher than a gate terminal voltage. SOLUTION: A transistor 304 for lowering a gate voltage and a coil current detecting part 305 are provided in a MOS gate structure transistor (e.g. IGBT) 303, and the serially connected resistor 309 and high pressure resistant rated current element 308 of a circuit for increasing a gate terminal voltage by a collector terminal voltage are connected between the collector and the gate of the IGBT 30. A gate voltage is applied so as to make constant a collector voltage in the transistor 304 and raised instantly following the rising of the collector voltage. When the collector voltage is higher than the gate voltage, the gate voltage is increased by the rising of the collector voltage immediately after the starting of a current regulating operation, the collector current is also increased and thus the vibration of the collector voltage is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition circuit for igniting an engine of an automobile or the like which produces a spark in a spark plug due to a high voltage generated on a secondary side when a primary current of an ignition coil is interrupted by a switching means. The present invention relates to a power semiconductor device used.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional example of an ignition circuit for engine ignition. In FIG. 6, when the current flowing through the battery 101 in the primary winding of the ignition coil 102 is cut off by the bipolar Darlington transistor 103 (switching means), the spark plug (ignition plug) is sparked by the high voltage generated in the secondary winding. Discharge and drive the internal combustion engine.

The details of this circuit will be described below.
A resistor 106 is connected to the emitter terminal side of the bipolar Darlington transistor 103 to detect the main circuit current for limiting the current. The resistor 106 is shown in FIG. 1 of Japanese Patent Publication No. 55-3538 and USP 35875.
It is publicly known in FIG. As a current limiting circuit, a transistor 104 for shunting the base current of the bipolar Darlington transistor 103 is provided between the base of the bipolar Darlington transistor 103 and the ground side of the main circuit current detection resistor 106.
The base terminal of the transistor 104 is connected to the connection point between the main circuit current detection resistor 106 and the emitter terminal of the bipolar Darlington transistor via the resistor 111. The load current flowing through the primary winding of the ignition coil 102 is the bipolar Darlington transistor 10
3 to the main circuit current detection resistor 106. When the voltage drop of the main circuit current detection resistor 106 caused by this current becomes about 0.6 V or more, this main circuit current detection resistor 106
The base-emitter voltage of the transistor 104 connected to the transistor also becomes about 0.6 V or more, and the transistor 104 operates to operate the bipolar Darlington transistor 103.
A part of the base current of is shunted to the transistor 104.
When the base current of the bipolar Darlington transistor 103 decreases due to the shunt to the transistor 104, the collector current, which is a load current, also decreases. However, since the ignition coil 102 has a large inductance, the load current will continue to flow. As a result, the collector-emitter voltage of the bipolar Darlington transistor 103 is increased, and as a result, the load current (= collector current) becomes a constant value and the voltage drop of the main circuit current detection resistor 106 is kept constant (so-called current limiting). Operation works).

By the way, the resistor 111 and the capacitor 112
Is not disclosed in the above-mentioned patent, but is for suppressing current oscillation during current limiting, which is a known technique. The resistance 1
The drive circuit 109 including the transistors 07 and 108 and the transistor 105 uses the voltage of the battery 101 as a drive circuit power source,
Bipolar when transistor 105 is off
Darlington transistor 103 has resistors 108 and 107
It allows the base current limited by. However, the drive circuit is not limited to this.

Further, a Zener diode 110 is connected between the collector terminal and the base terminal of the bipolar Darlington transistor 103. The function of the Zener diode 110 will be described below. When the base current of the bipolar Darlington transistor 103 is removed and the bipolar Darlington transistor 103 is turned off, an overvoltage is applied from the ignition coil 102 to the bipolar Darlington transistor 103. At this time, a reverse current flows through the Zener diode 110 due to the Zener diode 110 whose breakdown voltage is set lower than the breakdown voltage between the main terminals of the bipolar Darlington transistor. Part of this reverse current becomes the base current of the bipolar Darlington transistor 103, and
The collector-emitter voltage of the Darlington transistor 103 is clamped to the breakdown voltage of the Zener diode 110. This protects the bipolar Darlington transistor 103 from overvoltage. Further, at this time, most of the electric charges discharged from the ignition coil are discharged as a collector current of the bipolar Darlington transistor 103. This Zener diode 110 is known from USP 4030469. Also MO
An example of a method for manufacturing a Zener diode for an S-gate structure transistor is disclosed in US Pat. No. 5,115,369.

An example in which a capacitor is used instead of the Zener diode 110 is disclosed in Japanese Utility Model Publication No. 55-48132, which is shown for protecting a transistor connected in series with an ignition coil. In the circuit of FIG. 6, the bipolar Darlington transistor 10
FIG. 2 shows collector-emitter voltage and collector current waveform before and after the current limiting operation of No. 3 in FIG. In the waveform of FIG. 2, the timing at which the collector-emitter voltage drops sharply from 16 V to about 1 V at the position on the left side of the paper is when the base current (not shown) is supplied to the bipolar Darlington transistor 103. Match. After that, the collector current changes according to a change amount (collector current change amount dic / dt = power supply voltage value / ignition coil inductance value per unit time) determined by the power supply voltage and the inductance of the ignition coil. This leads to a current limiting operation in which the collector current has a constant value. The collector-emitter voltage value while the collector current is being limited is the value obtained by subtracting the voltage drop due to the resistance component (mainly the ignition coil resistance) of the main circuit from the power supply voltage value.

[0007]

The above is the case where the bipolar Darlington transistor is applied to the element for controlling the ignition coil current. For example, as shown in FIG.
The transistor 105 and the resistor 108 of the driving circuit 109 are removed, and a wide temperature range (-40 to 40 V
Attempting to achieve the above-mentioned function at 150 ° C.) requires a large-capacity 5V system logic element having a current carrying capacity of 20 to 50 mA, depending on the current amplification factor characteristics of the bipolar Darlington transistor.

In order to reduce the drive current of the above-mentioned 5V system logic element by one digit or more in order to reduce the size of the total system, a voltage drive type MOS gate structure transistor is used as the element for controlling the ignition coil current. If adopted, it can be easily achieved. When the current MOS gate structure transistor (power MOSFET and IGBT) is replaced with the bipolar Darlington transistor of FIG. 6, the drain-source voltage is increased in the process of abrupt increase of the drain voltage at the start of current limiting as shown in FIG. Becomes a voltage higher than the power supply voltage, and moreover, there is a phenomenon that it vibrates greatly although it is an attenuation waveform. FIG. 3 is a voltage waveform and a current waveform showing the vibration phenomenon. The figure shows 250V
7 is a waveform of a drain voltage and a drain current (ignition coil current) when the ignition coil current is controlled by a withstand voltage and 5V driving MOSFET. Therefore, it is conceivable to optimize the capacitance values of the resistor 111 and the capacitor 112 in FIG. 6 or to reduce the ratio (gain or amplification factor) of the output signal to the base signal of the transistor 104 shown in FIG. Although it is effective in suppressing the current oscillation introduced when the collector current becomes constant, it is not useful in preventing the above-mentioned vibration phenomenon.

The oscillation of the drain voltage waveform shown in FIG. 3 causes the following problems. (1) On the high voltage side (secondary winding) of the ignition coil,
A voltage proportional to the oscillating collector voltage is induced, which may cause a spark to fly to the spark plug at an unexpected timing. (2) When a circuit for monitoring the drain voltage is added to monitor the operating condition of the ignition system, the oscillation of the drain voltage immediately after the start of the current limitation becomes a harmful effect. (3) The oscillation of the drain voltage waveform may lead to the waveform oscillation during the entire current limiting operation period.

On the other hand, in the bipolar Darlington transistor, the reason why the collector voltage oscillation phenomenon immediately after the start of current limitation is suppressed to a very small amount as in the MOS gate structure transistor is represented by the collector voltage on the horizontal axis and the collector current on the vertical axis. The output characteristic is significantly different from the MOS gate structure transistor. FIG. 4 shows the output characteristics of a bipolar Darlington transistor currently put into practical use in an automobile ignition circuit, and FIG. 2 is an operation waveform diagram using this transistor. On the other hand, FIG. 5 shows a MOS gate structure transistor (here, the MOSFE structure) which brings about the waveform of FIG.
It is an output characteristic view of T). Of course, even in IGBT, MOSF
The output characteristics are similar to those of ET. A significant difference between the characteristics shown in FIGS. 4 and 5 is the amount of change in the collector current due to the increase in the collector voltage when the collector voltage is about 2V or higher. It can be seen that the amount of change in the bipolar Darlington transistor is larger.

The mechanism of the bipolar Darlington transistor with less collector voltage oscillation can be explained as follows. As described in the section of the prior art, when the voltage of the resistor 106 increases in proportion to the increase of the collector current (which is also the ignition coil current),
Eventually, a base current flows through the transistor 104, and conduction is started between the collector and emitter of the transistor 104.

At this time, a part of the current flowing as the base current of the Darlington transistor 103 via the resistors 108 and 107 is shunted as the collector current of the transistor 104 due to the start of conduction of the transistor 104. If the voltage across the resistor 106 is going to increase further,
The voltage operates to increase the base current of the transistor 104 and decrease the base current of the transistor 103. Finally, the voltage across the resistor 106 is substantially concentrated on the base-emitter voltage characteristic of the transistor 104, and as a result, the collector current of the transistor 103 maintains a constant value. On the other hand, a time difference naturally occurs after the base current starts flowing through the transistor 104 and before the collector current of the transistor 103 becomes constant. Therefore, the base current of the transistor 103 will be
01 voltage and the values substantially determined by the resistors 108 and 107 gradually decrease.

From the gradually decreasing base current and the output characteristic of the bipolar Darlington transistor having the characteristic shown in FIG. 4, there is a gradual increase in collector voltage before the current limiting operation in the operating waveform of FIG. 2 is started. Understandable.
This gentle increase in the collector voltage makes the change in the collector current just before the start of the current limiting operation slow. The gradual change in collector voltage and collector current contributes to the suppression of collector voltage oscillation.

As shown in FIG. 4, the collector voltage is about 2V.
When the change in the collector current is large, if the time difference is zero, the voltage of the battery 101 and the resistances 108 and 107
Even if the base current of the transistor 103 changes stepwise from a base current value that is substantially determined by, to a certain base current value, the oscillation of the collector voltage immediately after the start of current limitation can be predicted to be extremely small for the following reason. That is, the jump (oscillation) of the collector voltage immediately after the start of the current limitation does not occur unless at least the change in the ignition coil current changes from the increase change to the decrease change with respect to time. When the collector current changes in a decreasing direction with time and the collector voltage is going to increase under a certain base current, the collector current of the transistor having the output characteristic as shown in FIG. This works in the direction of increasing the collector current to be reduced, in other words, the transistor itself has a so-called negative feedback function in which the collector voltage rises as the collector current decreases. This negative feedback function makes it difficult for the ignition coil current to change from increasing to decreasing, and suppresses the oscillation of the collector voltage.

On the other hand, in the MOS gate structure transistor as shown in FIG. 5, the change in collector current is extremely small when the collector voltage is about 2 V or more, and therefore the increase in collector current due to the increase in collector voltage is extremely small. Therefore, the negative feedback function is extremely weak, so that the oscillation of the collector voltage is not suppressed. An object of the present invention is to solve the above problems and provide an internal combustion engine ignition circuit device and an internal combustion engine ignition semiconductor device that can suppress the oscillation of the collector voltage.

[0016]

In order to achieve the above object, the present invention provides (1) a primary winding of an ignition coil, a DC power source and a switching means are connected to one of the secondary windings of the ignition coil. Connect the spark plug to the end,
In the device for supplying a high voltage generated in the secondary winding to the ignition plug by the change of the primary current of the ignition coil due to the opening / closing of the switching means, the switching means is M
An OS gate structure transistor, which includes at least a coil current detection unit and a circuit for lowering the gate voltage of the MOS gate structure transistor in order to limit the coil current of the primary winding to a certain constant value. When the main terminal voltage on the higher value side is higher than the gate terminal voltage, a current supply circuit for applying to the gate terminal the voltage generated by the current flowing from the main terminal to the gate terminal is provided. In addition, the magnitude of minute current is 0.01m
It is good that it is A to 10 mA, preferably several mA. Further, (2) when the main terminal voltage is equal to or lower than a predetermined voltage and is equal to or lower than a voltage value set within a range higher than the gate terminal voltage, a minute current flowing from the main terminal to the gate terminal is generated. When the generated voltage is applied to the gate terminal according to a constant value or the difference between the main terminal voltage value and the gate terminal voltage value, and when it is higher than the set voltage value, the voltage generated by the minute current A circuit that suppresses, decreases, or cuts off the increase of The predetermined voltage value may be 20V to 30V, preferably 25V. Further, (3) the above (1) and (2) are applied during a period in which a gate voltage applied in advance is applied.
It is assumed that a circuit for performing the above operation is provided. Further, (4) a detection circuit (monitor circuit) for detecting the voltage across the coil is provided, and when the voltage across the coil is opposite to the main circuit power supply voltage and a drop of more than the gate terminal voltage value occurs, a small current flows to the gate terminal. It is also possible to provide a circuit for applying the voltage generated in 1 between the detection circuit and the gate terminal, and further to provide a means for applying a voltage generated by a minute current to the gate terminal to a circuit that operates only during a period when the gate voltage applied in advance is applied. Good. (5) A direct current power supply and switching means are connected to the primary winding of the ignition coil, an ignition plug is connected to one end of the secondary winding of the ignition coil, and the primary current of the ignition coil is changed by opening and closing the switching means. In which a high voltage generated in the secondary winding is supplied to the spark plug, the switching means is a MOS gate structure transistor, and at least a coil current detector is provided to limit the coil current of the primary winding to a certain constant value. A control device comprising a circuit for decreasing the gate voltage of a MOS gate structure transistor, wherein the operating point of the control device (determined by the control device) is set to a point where there is little change due to temperature or its vicinity. And Further, (6) a part or all of the circuit excluding the storage battery and the coil is made into one chip or one package. (7) The output characteristics of the MOS gate structure transistor connected in series with the coil are in the range substantially equal to the coil current for limiting the current, and the gate voltage is fixed to a certain constant voltage, which increases the main terminal current. Area where there is almost no change in voltage between main terminals due to
In the region where the voltage between the main terminals increases sharply (the region where the current is limited) after shifting from the saturation region in the IGBT),
At least until the voltage between the main terminals reaches the first predetermined value, it is preferable that the change in the main terminal current is equal to or more than the second predetermined value with respect to the voltage between the main terminals of 1V. The first predetermined value may be 16V and the second predetermined value may be 0.1A.

According to the above (1), in the MOS gate structure transistor in which the collector current changes little with respect to the collector voltage change when the collector voltage is about 2 V or more as shown in FIG. 5, the collector current is changed from the saturation region to the current limiting region. At the time of shifting to, the collector voltage oscillation phenomenon occurs. In FIG. 3, when a MOSFET is used as the MOS gate structure transistor, an oscillation phenomenon is observed in the drain voltage corresponding to the collector voltage of the IGBT. As a measure against this,
If the collector voltage is higher than the gate voltage, a circuit that applies a voltage generated by a minute current from the collector terminal to the gate terminal to the gate terminal in the current limiting region increases the collector voltage immediately after starting the current limiting operation. Acts to increase the gate terminal voltage, and the rise in the gate voltage promotes an increase in the collector current. Therefore, the output characteristics of the MOS gate structure transistor become as if they were the output characteristics of the bipolar Darlington transistor, and the abrupt collector voltage increases. Suppress the rise of. Further, if the collector voltage due to the vibration moves so as to decrease, the action of increasing the gate voltage from the collector terminal decreases, and the gate voltage is reduced, and the decrease of the collector voltage is suppressed.

Further, the gate voltage of the MOS gate structure transistor is determined by the transistor 304 of FIG.
Since the collector current of No. 03 operates so as to be constant, the collector current instantly rises following the rise of the collector voltage. Therefore, when the collector voltage is higher than the gate voltage, applying a voltage generated by a minute current from the collector terminal to the gate terminal makes the output characteristics of the MOS gate structure transistor as shown in FIG. It is nothing but conversion to the output characteristics of the transistor.
According to (2), the battery voltage of an automobile that is widely used at present is 12V, but it is also assumed that two 12V batteries are connected in series and set to 24V to start the engine. Therefore, the power supply voltage when the ignition coil current is current limited is 24V (24V in this case).
V is 20 V to 30 V only when the engine is started and the voltage fluctuation at this time is taken into consideration, but the voltage here may change in the future). Also, M when current is limited
The collector voltage of the OS gate structure transistor has the above-mentioned contents, and it is necessary to take into consideration the power supply voltage value. In consideration of this voltage value, the operation of the above (1) functions sufficiently with the current power supply at 25 V or less, and under a high collector voltage exceeding 25 V, the operation of increasing the gate terminal by the collector terminal voltage is restricted. Is. The reason for suppressing the above operation under a high collector voltage exceeding 25 V is that the transistor 3 of FIG. 1 is removed when the connection between the battery electrode and the wiring terminal is disconnected due to the power surge of the automobile.
04 is required to pass the current sufficiently. But,
Since a surge voltage is rarely generated due to disconnection of the battery electrode portion, it is uneconomical to increase the current carrying capacity of the transistor 304 in FIG. Therefore, when the collector voltage exceeds 25 V at least during the current limiting operation, the increase of the minute current flowing from the collector terminal to the gate terminal is suppressed,
It is effective to prevent the transistor 304 in FIG. 1 from increasing in size by reducing or blocking. Of course, the increase in the voltage generated by the minute current is also suppressed, or this voltage is reduced or cut off.

According to (3), there are two reasons for suppressing the above-mentioned operation under a high collector voltage exceeding at least 25V.
The second is as follows. That is, this is a case where the gate voltage from the drive circuit 307 in FIG. 1 disappears and the MOS gate structure transistor (IGBT 303) shifts to the off state.
When the IGBT 303 turns off, the collector voltage is about 400
Although the voltage reaches about V, if the action of increasing the gate terminal voltage by the collector terminal is continued, a relatively large current flows into the drive circuit 307 of FIG.

The collector voltage of the IGBT is substantially clamped by the voltage of the Zener diode 312 shown in FIG. 1. During this clamping operation, the current flowing through the Zener diode is shown in FIG.
To the driving circuit 307, causing a voltage drop in the driving circuit 307. When this generated voltage rises to a gate voltage at which the IGBT 303 can operate, the IGBT 303 conducts and processes most of the ignition coil discharge energy.

However, if the collector voltage, which is one of the means of the present invention, is higher than the gate voltage and the operation of increasing the gate terminal voltage by the collector terminal voltage is continued, there is a possibility that the current will be higher than the Zener diode current.
This current increases the voltage drop in the drive circuit 307 of FIG. 1 and hinders the processing of the ignition coil discharge energy at the collector voltage of the IGBT 303, which is approximately equal to the Zener diode voltage. That is, a new problem arises in that the collector voltage of the IGBT 303 cannot reach the Zener diode voltage. In order to solve this problem, when the gate voltage is applied depending on the presence or absence of the gate voltage from the drive circuit of FIG. 1, when the gate terminal voltage is higher than the collector terminal voltage during the current limiting operation, 1 is performed. On the other hand, when there is no gate voltage from the drive circuit of FIG. 1, the operation of increasing the gate terminal voltage is canceled, and the gate voltage of the IGBT 303 is increased by the Zener diode 312 current of FIG.
This brings about the effect of allowing the accumulated ignition coil energy to be reliably released.

According to (4), in the circuit as shown in FIG.
When replaced with a gate structure transistor, the above (1)
This is another method that brings about an operation (or effect) equivalent to. In (1), when the collector voltage of the transistor is higher than the gate terminal voltage, the voltage generated by the minute current flowing from the collector terminal to the gate terminal is applied to the gate terminal. On the other hand, (4) indirectly monitors the collector voltage by detecting (monitoring) the voltage across the coil, and when the collector voltage is higher than the gate terminal voltage, a voltage generated by a minute current is applied to the gate terminal. The same function as the above (1) and the same effect are obtained.

According to (5), the transistor 30 of FIG.
By making the operating point of 4 a point where the temperature change is small, the change in the current limit value is reduced even if the external temperature changes. According to (6), the output characteristic of the MOS gate structure transistor is set to be similar to that of the current bipolar Darlington transistor, and a semiconductor device in which a circuit for suppressing collector voltage oscillation immediately after the start of current limiting is integrated is integrated.

According to (7), in the output characteristics of the MOS gate structure transistor of (6), in the current limiting region where the collector voltage is at least up to 16V, the change in collector current is 0 for a collector voltage of 1V. .1
A semiconductor device capable of suppressing the collector voltage oscillation by setting A or more. In practice, it is difficult to suppress vibration at 0.1 A or less.

[0025]

FIG. 1 is a diagram showing a circuit configuration of a first embodiment of the present invention. In this embodiment, as a circuit for increasing the gate terminal voltage by the collector terminal voltage, a resistor 309 and a high breakdown voltage constant current element 308 connected in series are connected between the collector and the gate. This combination corresponds to the structure of claim 1. It is considered that the high breakdown voltage constant current element 308 uses a depletion structure MOSFET and an IGBT, and may be incorporated in a part of the IGBT 303 in FIG. Further, the withstand voltage of the high withstand voltage constant current element 308 may be set lower than the withstand voltage of the IGBT 303 so that the Zener diode 312 also has the function. Alternatively, the high breakdown voltage constant current element 308 may be a circuit such as a series power supply.

By the value of the constant current of the high breakdown voltage constant current element 308 and the value of the resistor 309, the increase of a minute current flowing from the collector terminal to the gate terminal, which is the content of claim 3, is suppressed and a constant current is obtained. 12A and 12B show an example in which the collector voltage to be set can be set. FIG. 10A shows the relationship between the gate-source voltage and the source-drain voltage of the depletion type MOSFET and the drain current. When the gate-drain voltage is zero, the drain current saturates at 2 mA and has a constant value independent of the source-drain voltage. Therefore, it functions as a constant current element. In the same figure (b), the value of the resistance R (corresponding to the resistance 309) is 3k.
The relationship between the collector voltage Vc of the IGBT and the minute current I flowing from the collector terminal to the gate terminal through the resistor R when Ω, 5 kΩ, and 8 kΩ are shown. The collector voltage Vc, which is a saturated current value of 2 mA, is 6 V when the resistance R is 3 kΩ, 10 V when the resistance R is 5 kΩ, and 8 k.
When it is Ω, it is 16V. That is, the product of the resistance R and 2 mA is the collector voltage V _C at which the minute current I is saturated, and the resistance R
This collector voltage Vc can be changed by changing the value of. When the minute current I is unsaturated, the minute current I also increases in proportion to the collector voltage Vc. Since the gate voltage of the transistor 304 in FIG.
9 and the resistor 306 divide the voltage, and the gate voltage increases as the collector voltage Vc increases. Therefore, the collector current also increases. Therefore, the output characteristic of the IGBT 303 becomes similar to the output characteristic of the bipolar Darlington transistor shown in FIG. As a result, oscillation of the collector voltage is suppressed and a constant collector current is maintained.
As can be seen from FIG. 12B, if the value of the resistance R is increased, the collector voltage Vc at which the minute current I is saturated can be increased and the effect of suppressing the collector voltage oscillation can be enhanced. The value of the minute current I may be 0.01 mA to 10 mA, and the range of 0.5 mA to 10 mA is practical, preferably about 1 mA to 3 mA. When this current value becomes large, the amount of energy stored in the ignition coil consumed by the current becomes large, and it may become impossible to secure the spark voltage. On the other hand, if it is too small, the output characteristic approaches from the bipolar Darlington transistor characteristic to the MOSFET characteristic and the collector voltage waveform oscillates. On the other hand, IGBT30
It is necessary to maintain the voltage generated in the ignition coil at several hundreds V in order to turn off the ignition coil 3, turn off the ignition coil current, and discharge the spark plug with the energy stored in the ignition coil. For that purpose, it is necessary to make the ignition coil current as small as possible, and it is necessary to make the constant current value flowing through the high withstand voltage constant current element as small as several mA even at high voltage. That is, in this embodiment, the resistor 309 is inserted between the gate and the collector in order to make the output characteristic of the IGBT 303 the output characteristic of the bipolar Darlington transistor, and the high breakdown voltage constant current element 308 is connected to the resistor 309 in order to secure the spark voltage. It is connected in series. Further, the configuration of either the resistor 309 or the high withstand voltage constant current element 308 is also conceivable. This is claim 1
This corresponds to the configuration of

FIG. 7 is a diagram showing a circuit configuration of a second embodiment of the present invention. As a circuit for increasing the gate terminal voltage by the collector terminal voltage, a series circuit of a resistor 208 and a capacitor 209 is provided between the collector and the gate. Connected to. The resistor 208 has the same function as the resistor 309 of the first embodiment. The capacitor 209 is connected from the ignition coil 202 to the IGBT 20 when the IGBT 203 is turned off.
3 absorbs the current that is about to flow to 3 and sharply decreases it, and at the same time, increases the voltage of the gate by the electric charge due to the minute current from the ignition coil 202 to secure the spark voltage. It operates similarly to a withstand voltage constant current element. Incidentally, only the capacitor 209 may be used.

Further, the resistor 206 has an effect of reducing the amount of change in drain voltage with respect to the gate terminal of the MOSFET 204, further emphasizes the effect of increasing the gate voltage by the resistor 208 and the capacitor 209, and has an effect of suppressing oscillation of the collector voltage. Further, the high-voltage constant current element 308 of FIG. 1 may be connected in series to the series circuit of the resistor 208 and the capacitor 209 of the second embodiment.

In the first and second embodiments, I
The transistors 304 and 204 for lowering the gate voltage of the GBTs 303 and 203 are single transistors and MO transistors.
Operation amplifier (op amp) other than SFET
Circuits such as the above can be used, and even these are effective. FIG. 8 is a diagram showing the circuit configuration of the third embodiment of the present invention. The resistor 410 corresponds to the resistor 208 of the first embodiment, and when the IGBT 401 is turned off and the collector voltage becomes at least 25 V or more, the resistor 410 is used.
This is an example of a circuit in the case where a MOSFET 403 cuts off a minute current flowing through the MOSFET. Drive circuit (with internal resistance, of course)
Gate voltage is applied to the IGBT 401 from the
Turn 1 on. This IGBT 401 has a current detection terminal, and is commonly called a current sense IGBT. This current detection terminal is connected to the ground point via the resistor 405. The ignition coil current becomes a collector current and flows out through the IGBT 401. Then, the increasing collector current is shunted to the current detection terminal to raise the potential at the upper end of the resistor 405 to turn on the MOSFET 402. At this time, the MOSFET 404 is the IGBT 4
Since the collector-emitter voltage of 01 is extremely small, it is in the off state. Then, the MOSFET 403 is turned on, the resistor 410 is connected to the gate terminal of the IGBT 401, and a minute current flows through the resistor 410 and the MOSFET 40.
3 and MOSFET 402, IGBT4
As the gate voltage of 01, a voltage generated by the on resistance of the MOSFET 402 is applied. The collector current is MOSFET4
The function of 02 finally provides a constant current. Also the resistor 41
By connecting 0 to the gate terminal of the IGBT 401, the output characteristic is changed to the output characteristic of the bipolar Darlington transistor, thereby suppressing oscillation of the collector voltage. Further, the MOSFET 403 is necessary to cut off a minute current from the ignition coil when the IGBT 401 is turned off and to ensure the spark voltage.
Further, although not shown, if an additional resistor is connected in parallel between the drain and the source of the MOSFET 403, it becomes an embodiment in the case of reducing the minute current at least when the collector voltage is 25 V or more.

FIG. 9 is a diagram showing the circuit configuration of the fourth embodiment of the present invention. IGB with resistor 512 and MOSFET 503
A voltage generated by a minute current is applied to the gate terminal of T501 to bring the output characteristics of the IGBT 501 close to the output characteristics of the bipolar Darlington transistor. That is, the resistor 512 corresponds to the resistor 410 of the third embodiment, and the MOSF
The ET503 corresponds to the MOSFET 403 of the third embodiment.

Operation amplifier (operational amplifier)
502 is an emitter terminal of the IGBT 501 and a MOSFET
The gate terminals of 504 are connected via a resistor 507 so that this operational amplifier operates only during the application period of the gate voltage applied from the drive circuit 513 to the IGBT 501 in advance. FIG. 10 is a diagram showing the circuit configuration of the fifth embodiment of the present invention. Voltage detection circuit (monitor circuit) 6 for detecting and monitoring the voltage of the ignition coil 602
One side of 08 is connected to both ends of the ignition coil 602, and the other side is connected to the minute current circuit 609. The minute current circuit 609 is the minute current switch circuit 61.
1 is connected to the gate terminal of the IGBT 603. If the ignition coil voltage has a polarity opposite to the main circuit power supply voltage or a polarity that adds to the main circuit power supply voltage and a drop of more than the gate voltage value occurs, the micro current circuit can supply the voltage generated by the micro current to the gate terminal, and It suppresses voltage oscillation. The IGBT 603 has a current detection terminal. In the figure, the minute current circuit functions as the resistor 410 of the third embodiment, and the minute current switch circuit 611 functions as the MOSFET 403.

FIG. 11 is a diagram showing an example of setting the operating point where the temperature change of the transistor constituting the control device is small.
Here, an example using a MOSFET as a transistor is shown. Of course, circuit components used in the control device (transistors 304, 204, etc. and the operation amplifier 50
11 is shown as an example of reducing the temperature change of the operating point of the circuit (2, etc.). In FIG. 11, the temperature change of the current limit value can be reduced by setting the intersecting point as the operating point.

FIG. 13 is an operation waveform diagram when the power MOSFET having the output characteristic shown in FIG. 5 is applied to the circuit of FIG. Since the output characteristic of the MOSFET becomes close to that of the bipolar Darlington transistor by installing the circuit of the present invention, the oscillation of the drain voltage shown in FIG. 3 disappears. In each of the above embodiments, the IG
The BT, the current limiting circuit, and the minute current supply circuit can be configured by one chip. Further, the drive circuit can be included in one chip, or the individual elements may be mounted on a ceramic substrate or a metal insulating substrate and housed in a case to form one package. Moreover, the ignition coil may be included in one module.

Although the present invention has been described with reference to an example in which a MOS gate structure transistor is applied to an internal combustion engine ignition circuit device, the present invention is not limited to this, and may be applied to a circuit including an inductive component in a wiring system. It has a remarkable effect. For example, the circuit device of the present invention can be used as a switching element used in each arm of a bridge circuit of an inverter that drives a motor. When used to control an inductive load other than such an ignition circuit device, M
It has the effect of controlling the surge voltage when the OS gate structure transistor is off.

[0035]

As described above, according to the present invention,
First, the present invention enables high-speed switching with a drive current lower than that of the conventional bipolar Darlington transistor.
The OS gate structure transistor can be applied to an automobile ignition circuit. Secondly, the spark plug is prevented from generating sparks at unscheduled timings during the constant current operation of the ignition coil current of the MOS gate structure transistor having the first effect. Thirdly, the oscillation of the drain voltage immediately after the start of the current limitation, which is a harmful effect when a circuit for monitoring the drain voltage is added to monitor the operating condition of the ignition system, which brings about the first effect, is prevented. Fourthly, the waveform vibration is prevented during the entire current limiting operation. The above effects are achieved.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an ignition circuit device according to a first embodiment of the present invention using an IGBT.

[Fig.2] Collector voltage / current waveform diagram at the time of current limitation in bipolar Darlington transistor

FIG. 3 Waveform diagram of collector voltage and current when current is limited in power MOSFET

[Figure 4] Output characteristic diagram of bipolar Darlington transistor

FIG. 5: Power M withstand voltage of 250 V and on-resistance of 0.16 Ω
Output characteristics of OSFET

FIG. 6 is a conventional circuit diagram using a bipolar Darlington transistor.

FIG. 7 is a circuit diagram of an ignition circuit device according to a second embodiment of the present invention using an IGBT.

FIG. 8 is a circuit diagram of an ignition circuit device according to a third embodiment of the present invention.

FIG. 9 is a circuit diagram of an ignition circuit device according to a fourth embodiment of the present invention.

FIG. 10 is a circuit diagram of an ignition circuit device according to a fifth embodiment of the present invention.

FIG. 11 is a diagram showing an example of setting an operating point with a small temperature change.

FIG. 12 is a diagram showing setting of a collector voltage at which suppression of an increase in a minute current or voltage applied from the collector terminal to the gate terminal is started.

13 is a power MOSFET having the output characteristic of FIG.
Waveform diagram when applying to the circuit of Figure 6

[Explanation of symbols]

101, 201, 301, 601 Battery 102, 202, 302, 602 Ignition coil 103 Bipolar Darlington transistor 104, 105, 304 Transistor 109, 207, 307, 411, 513, 610
Drive circuit 110,312 Zener diode 112,209,311,607 Capacitor 203,303,501 IGBT 204,402-404,503-505,604
MOSFET 308 High breakdown voltage constant current element 313 Diodes 401, 603 IGBT with current detection terminal 502 Operational amplifier 608 Monitor circuit 609 Micro current circuit 611 Micro current switch circuit

Claims (10)

[Claims] 1. A primary winding of an ignition coil is connected with a DC power source and a switching means, and an ignition plug is connected with one end of a secondary winding of the ignition coil, and the primary current of the ignition coil is opened and closed by opening and closing the switching means. In a device for supplying a high voltage generated in a secondary winding to a spark plug due to a change, the switching means is a MOS gate structure transistor, and at least a coil current detection unit is provided to limit the coil current of the primary winding to a certain constant value. And a circuit for lowering the gate voltage of the MOS gate structure transistor, the current flowing from the main terminal to the gate terminal when the main terminal voltage on the high voltage side of the MOS gate structure transistor is higher than the gate terminal voltage. Internal combustion circuit characterized by comprising a current supply circuit for applying a voltage generated at Seki ignition circuit device. 2. The current flowing from the main terminal of the MOS gate structure transistor to the gate terminal is 0.01 mA to 10 mA.
The circuit device for ignition of an internal combustion engine according to claim 1, wherein the circuit device is mA. 3. A current flowing from the main terminal to the gate terminal occurs when the voltage of the main terminal is equal to or lower than a predetermined voltage and lower than a voltage value set within a range higher than the gate terminal voltage. A voltage is applied to the gate terminal according to a constant value or the difference between the main terminal voltage and the gate terminal voltage, and when the voltage is higher than the set voltage value, the current flowing from the main terminal to the gate terminal is used. 2. The circuit device for igniting an internal combustion engine according to claim 1, further comprising a circuit for suppressing, decreasing or interrupting an increase in the generated voltage. 4. The internal combustion engine ignition circuit device according to claim 3, wherein the predetermined voltage value is 20V to 30V. 5. The internal combustion engine ignition circuit device according to claim 1, further comprising a circuit which is operated during a period in which a gate voltage applied in advance is applied. 6. A direct current power supply and a switching means are connected to the primary winding of the ignition coil, an ignition plug is connected to one end of the secondary winding of the ignition coil, and a primary current of the ignition coil is generated by opening and closing the switching means. In a device for supplying a high voltage generated in a secondary winding to a spark plug due to a change, the switching means is a MOS gate structure transistor, and at least a coil current detection unit is provided to limit the coil current of the primary winding to a certain constant value. And a circuit for lowering the gate voltage of a MOS gate structure transistor, which includes a detection circuit for detecting the voltage across the coil, a circuit for applying a voltage generated by a minute current to the gate terminal, and a gate voltage applied in advance. A circuit for igniting an internal combustion engine, comprising a circuit which is operated only during a period of being added Location. 7. A direct current power supply and switching means are connected to the primary winding of the ignition coil, an ignition plug is connected to one end of the secondary winding of the ignition coil, and the primary current of the ignition coil is opened and closed by opening and closing the switching means. In a device for supplying a high voltage generated in a secondary winding to a spark plug due to a change, the switching means is a MOS gate structure transistor, and at least a coil current detection unit is provided to limit the coil current of the primary winding to a certain constant value. A circuit device for igniting an internal combustion engine, comprising: a circuit for lowering a gate voltage of a MOS gate structure transistor, wherein an operating point of the control device is set to a point where a change due to temperature is small. 8. An internal combustion engine ignition circuit characterized in that a part or all of the circuit of the internal combustion engine ignition circuit device according to any one of claims 1 to 7 except for a DC power supply and an ignition coil is formed in one chip or one package. Semiconductor device. 9. A gate voltage supplied from a drive circuit is fixed to a constant value within a range in which an output characteristic of a MOS gate structure transistor connected in series with an ignition coil is substantially equal to a current-limited coil current. In the area where the voltage between the main terminals changes abruptly due to the change in the voltage between the main terminals due to the increase in the main terminal current, and the voltage between the main terminals increases to at least the first predetermined value, A semiconductor device for ignition of an internal combustion engine, wherein a change amount of a main terminal current is equal to or more than a second predetermined value with respect to an inter-voltage 1V. 10. A semiconductor device for ignition of an internal combustion engine according to claim 9, wherein the first predetermined value is 16V and the second predetermined value is 0.1A.