JP3186619B2 - Internal combustion engine ignition circuit device and internal combustion engine ignition semiconductor device - Google Patents

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 for an automobile or the like which generates a spark in a spark plug by a high voltage generated on a secondary side when a primary current of an ignition coil is turned on and off by a switching means, and to the ignition circuit. 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, the engine ignition
Nisshon circuit upon interruption of the current through the battery 101 to the primary winding of the ignition coil 102 in bipolar Darlington transistor 103 (switching means), a spark plug (spark plug) by a high voltage generated in the secondary winding The internal combustion engine is driven by spark discharge.

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 perform main circuit current detection for current limitation. This resistor 106 is described in FIG. 1 of Japanese Patent Publication No. 55-3538 and US Pat.
No. 51, which is known in FIG. 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 detecting resistor 106 as a current limiting circuit.
The base terminal of the transistor 104 is connected via a resistor 111 to a connection point between the main circuit current detecting resistor 106 and the emitter terminal of the bipolar Darlington transistor. The load current flowing through the primary winding of the ignition coil 102 is the bipolar Darlington transistor 10
3 flows 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, the main circuit current detection resistor 106
The voltage between the base and the emitter 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.
Is diverted to the transistor 104.
When the base current of the bipolar Darlington transistor 103 decreases due to the shunting to the transistor 104, the collector current, which is the load current, also acts to decrease. 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).

Incidentally, a resistor 111 and a capacitor 112
Although it is not disclosed in the above-mentioned patent, it is a known technique for suppressing current oscillation during current limitation. The resistance 1
A 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 supply,
When the transistor 105 is off,
Darlington transistor 103 with resistors 108 and 107
The base current limited by the above is caused to flow. 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 operation 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 by the Zener diode 110 whose breakdown voltage is set lower than the breakdown voltage between the main terminals of the bipolar Darlington transistor. This reverse current partially becomes the base current of the bipolar Darlington transistor 103, and
The collector-emitter voltage of the Darlington transistor 103 is substantially clamped to the withstand voltage of the Zener diode 110. This protects the bipolar Darlington transistor 103 from overvoltage. At this time, most of the electric charge emitted from the ignition coil is emitted as the collector current of the bipolar Darlington transistor 103. The Zener diode 110 is known from US Pat. No. 4,030,469. Also MO
An example of a method for manufacturing a Zener diode for an S-gate transistor is disclosed in US Pat. No. 5,115,369.

An example in which a capacitor is used in place of the Zener diode 110 is disclosed in Japanese Utility Model Publication No. Sho 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 is used.
FIG. 2 shows the collector-emitter voltage and the collector current waveform before and after the current limiting operation of No.3. 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 with respect to the paper surface is the time when a base current (not shown) is supplied to the bipolar Darlington transistor 103. Match. After that, the collector current changes by a change amount determined by the power supply voltage and the inductance of the ignition coil (collector current change amount per unit time dic / dt = power supply voltage value / ignition coil inductance value). This leads to a current limiting operation in which the collector current becomes a constant value. In addition, the collector-emitter voltage value while the collector current is limited is a value obtained by subtracting the voltage drop due to the resistance component of the main circuit (mainly the ignition coil resistance) from the power supply voltage value.

[0007]

The above is a case where a bipolar Darlington transistor is applied to an element for controlling an ignition coil current.
The transistor 105 and the resistor 108 of the drive circuit 109 are removed, and a wide temperature range (-40 to 40
If the above function is to be achieved at 150 ° C.), a large-capacity 5 V logic element having a current carrying capacity of 20 to 50 mA is required, although it depends on the current amplification characteristics of the bipolar Darlington transistor.

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

The oscillation of the drain voltage waveform shown in FIG. 3 causes the following problem. (1) On the high voltage side (secondary winding) of the ignition coil,
A voltage proportional to the oscillating collector voltage is induced, and there is a possibility that sparks may fly on the spark plug at unexpected timing. (2) When a circuit for monitoring the drain voltage is added in order to monitor the operation state of the ignition system, the oscillation of the drain voltage immediately after the start of the current limitation becomes an adverse effect. (3) This oscillation of the drain voltage waveform may lead to waveform oscillation during the entire period of the current limiting operation.

On the other hand, in a bipolar Darlington transistor, the reason why the collector voltage oscillation phenomenon immediately after the start of current limiting is minimal as in a MOS gate structure transistor is that the horizontal axis is the collector voltage and the vertical axis is the collector current. The output characteristic is significantly different from that of the MOS gate structure transistor. FIG. 4 shows the output characteristics of a bipolar Darlington transistor currently used in automobile ignition circuits, and FIG. 2 shows an operation waveform diagram using this transistor. On the other hand, FIG. 5 shows a MOS gate structure transistor (here, MOSFE) which produces the waveform of FIG.
It is an output characteristic figure of T). Of course, IGBTs are also MOSF
Output characteristics similar to ET are obtained. A significant difference between the characteristics shown in FIGS. 4 and 5 is a change in the collector current due to an increase in the collector voltage when the collector voltage is about 2 V or more. 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 related art, when the voltage of the resistor 106 increases in proportion to the increase of the collector current (which is also an ignition coil current),
Eventually, a base current flows through the transistor 104 and conduction between the collector and the emitter of the transistor 104 starts.

At this time, a portion of the current flowing as the base current of the Darlington transistor 103 via the resistors 108 and 107 is diverted as the collector current of the transistor 104 when the transistor 104 starts conducting. If the voltage between both ends of the resistor 106 is to be further increased,
The voltage operates to increase the base current of the transistor 104 and decrease the base current of the transistor 103. Finally, the voltage between both ends of the resistor 106 is substantially summarized in the base-emitter voltage characteristic of the transistor 104, and as a result, the collector current of the transistor 103 keeps a constant value. On the other hand, there is naturally a time difference from when the base current starts flowing through the transistor 104 to when the collector current of the transistor 103 becomes constant. Therefore, the base current of the transistor 103 varies within the time lag between the battery 1
01 and gradually decreases from a value substantially determined by the resistors 108 and 107.

From the gradually decreasing base current and the output characteristics of the bipolar Darlington transistor having the characteristics shown in FIG. 4, a gradual rise in the collector voltage before the current limiting operation in the operation waveform of FIG. 2 starts. It can be understood.
This gradual rise in the collector voltage slows down the change in the collector current immediately before the start of the current limiting operation. The gradual change in the collector voltage and the collector current contributes to the suppression of the oscillation of the collector voltage.

Further, as shown in FIG.
If the change in the collector current is large, the time difference is assumed to be zero and the voltage of the battery 101 and the resistors 108 and 107
Even if the base current of the transistor 103 changes stepwise from a base current value substantially determined by the equation (1) to a certain base current value, it can be predicted that the oscillation of the collector voltage immediately after the start of the current limitation is extremely small for the following reason. That is, a jump (oscillation) of the collector voltage immediately after the start of the current limitation does not occur unless at least the change of the ignition coil current changes from a change in increase to a change in time with respect to time. When the change of the collector current with time changes in the decreasing direction and the collector voltage tries to increase under a certain base current, the transistor having the output characteristic as shown in FIG. This means that the collector current to be reduced acts to increase, in other words, the transistor itself has a so-called negative feedback function in which the collector voltage increases with decreasing collector current. This negative feedback function makes it difficult for the ignition coil current to change from an increase to a decrease, and suppresses oscillation of the collector voltage.

On the other hand, in the MOS-gate transistor shown in FIG. 5, the change in the collector current when the collector voltage is about 2 V or more is extremely small, so the increase in the collector current due to the increase in the 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 provide an internal combustion engine ignition circuit device and an internal combustion engine ignition semiconductor device that can solve the above-mentioned problems and can suppress the oscillation of the collector voltage.

[0016]

In order to achieve the above object, the present invention provides (1) a method in which a DC power supply and a switching means are connected to a primary winding of an ignition coil, and one of secondary windings of the ignition coil is connected. Connect the spark plug to the end,
A high voltage generated in a secondary winding due to a change in a primary current of an ignition coil due to opening and closing of the switching means is supplied to a spark plug.
An OS gate transistor, comprising at least a coil current detector and a circuit for lowering the gate voltage of the MOS gate transistor to limit the coil current of the primary winding to a certain value; When the main terminal voltage on the high value side is higher than the gate terminal voltage, a current supply circuit for applying a voltage generated by a current flowing from the main terminal on the high voltage side to the gate terminal to the gate terminal is provided. I do. High voltage value
The magnitude of the minute current flowing from the main terminal on the side to the gate terminal is preferably 0.01 mA to 10 mA, and more preferably several mA. Further, (2) the main terminal voltage, the predetermined voltage is equal to or lower than, and, below the voltage value set in the range higher than the gate terminal voltage is small flowing into the gate terminal of the main terminal voltage generated by the current, as applied to the gate terminal in accordance with the difference between the values of the gate terminal voltage of a constant value or the main terminal voltage, and, if higher than the voltage value set, said the micro A circuit that suppresses, decreases, or shuts off an increase in voltage generated by current is provided. This predetermined voltage value is 20V
To 30V, preferably 25V.
Further, (3) a circuit for operating the current supply circuit of (1) or (2) during a period in which a gate voltage added in advance is applied is provided. (4) A detection circuit (monitor circuit) for detecting the voltage across the coil is provided, and the voltage across the coil has a polarity opposite to the main circuit power supply voltage. A means for applying a voltage generated by the micro-current circuit between the detection circuit and the gate terminal, and a means for applying a voltage generated by the micro-current to the gate terminal operates the micro-current circuit only during a period in which the gate voltage applied in advance is applied. A circuit may be provided. The (5) M OS circuits operating point of lowering the gate voltage of the gate structure transistor (where determined by the control device) point change with temperature is small and, or and be set to the vicinity thereof. (6) Part or all of the circuit excluding the storage battery and the coil is made into one chip or one package. Also, (7)
The output characteristics of the MOS gate structure transistor connected in series with the coil are within a range substantially equal to the coil current for limiting the current, and the gate voltage is fixed to a certain voltage, and the voltage between the main terminals due to an increase in the main terminal current In a region where there is almost no change (a resistance region for a MOSFET and a saturation region for an IGBT) and a voltage between main terminals increases rapidly (a region where current is limited), at least a voltage between the main terminals becomes the first voltage. Up to a predetermined value, voltage between main terminals 1V
In contrast, the change in the main terminal current may be equal to or greater than a second predetermined value. Also, the first predetermined value is 16V
In this case, the second predetermined value may be 0.1A.

According to the above (1), in the MOS gate transistor having a small change in the collector current with respect to the change in the collector voltage when the collector voltage is about 2 V or more as shown in FIG. 5, the collector current changes from the saturation region to the current limiting region. Oscillation of the collector voltage occurs at the point of transition to. In FIG. 3, when the 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,
When the collector voltage is higher than the gate voltage, a circuit that applies a small current generated from the collector terminal to the gate terminal to the gate terminal in the current limit area is provided to increase the collector voltage immediately after the current limit operation starts. Acts in the direction of increasing the gate terminal voltage, and the rise of the gate voltage promotes the increase of the collector current, so that the output characteristics of the MOS gate structure transistor become like the output characteristics of the bipolar Darlington transistor, and the sharp collector voltage Suppress the rise. Further, when moved as by Ri collector voltage to the vibration is reduced, reduces the effect of increasing the gate voltage from the collector terminal, the drop of the collector voltage becomes as if form gate voltage is narrowed down is suppressed.

The gate voltage of the MOS gate transistor is set by the transistor 304 of FIG.
Since the collector current of 03 operates so as to be constant, it rises instantaneously following the rise of the collector voltage. Therefore, when the collector voltage is higher than the gate voltage, applying a voltage generated from the collector terminal to the gate terminal by a very small current changes the output characteristic of the MOS gate structure transistor as shown in FIG. 5 to the bipolar Darlington 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 frequently used at present is 12 V, but it is also assumed that two 12 V batteries are connected in series and set to 24 V to start the engine. Accordingly, the power supply voltage at the time of limiting the ignition coil current is 24 V (24 V in this case).
V is only at the time of engine start, and is 20 to 30 V in consideration of voltage fluctuation at this time, but the voltage here may change in the future). M at the time of current limit
The collector voltage of the transistor having the OS gate structure has the above-described content, and it is necessary to take the power supply voltage value into view. In consideration of this voltage value, the operation of the above (1) sufficiently functions at a current power supply of 25 V or less, and limits the operation of increasing the gate terminal by the collector terminal voltage under a high collector voltage exceeding 25 V. It is. The reason for suppressing the above-described operation under a high collector voltage exceeding 25 V is that when the connection between the electrode of the battery and the wiring terminal is disconnected during the power supply surge of the vehicle, the transistor 3 of FIG.
04 is required to flow the current sufficiently. But,
Since the occurrence of a surge voltage due to the detachment of the battery electrode is rare, it is uneconomical to increase the current carrying capability of the transistor 304 in FIG. Therefore, when the collector voltage exceeds at least 25 V 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. 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), the second reason for suppressing the above-mentioned operation under a high collector voltage exceeding at least 25 V is as follows.
The first is as follows. That is, this is a case where the gate voltage from the driving circuit 307 in FIG. 1 is lost and the MOS gate structure transistor (IGBT 303) shifts to the off state.
When the IGBT 303 is turned off, the collector voltage becomes about 400
However, when 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.

Although the collector voltage of the IGBT is substantially clamped by the voltage of the Zener diode 312 in FIG. 1, during this clamping operation, the current flowing through the Zener diode is reduced as shown in FIG.
And causes a voltage drop in the drive circuit 307. When the 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 emission energy.

However, if the operation of increasing the gate terminal voltage with the collector terminal voltage is continued when the collector voltage, which is one means of the present invention, is higher than the gate voltage, the current may become higher than the Zener diode current.
This current increases the voltage drop in the driving circuit 307 of FIG. 1 and hinders the processing of the ignition coil emission energy at the collector voltage of the IGBT 303 which is substantially equal to the zener diode voltage. That is, there is a new problem 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 according to the presence or absence of the gate voltage from the drive circuit 307 in FIG. 1, the collector terminal voltage is higher than the gate terminal voltage during the current limiting operation. At this time, the operation of increasing the gate terminal voltage can be performed. On the other hand, when there is no gate voltage from the driving circuit 307 in FIG. 1, the operation of increasing the gate terminal voltage is canceled, and the current of the zener diode 312 in FIG. This has the effect of increasing the gate voltage of the IGBT 303 and ensuring that the ignition coil energy accumulated by the conduction of the IGBT 303 can be 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 provides the same operation (or effect) as. (1) is characterized in that when the collector voltage of the transistor is higher than the gate terminal voltage, a voltage generated by a minute current flowing from the collector terminal to the gate terminal is applied to the gate terminal. On the other hand, (4) monitors the collector voltage indirectly by detecting (monitoring) the voltage between both ends of the coil. When the collector voltage is higher than the gate terminal voltage, the voltage generated by the minute current is applied to the gate terminal. Thus, it performs the same function as the above (1) and has the same effect.

According to (5), the transistor 30 of FIG.
By setting the operating point 4 to a point where the temperature change is small, the change in the current limit value is reduced even when the external temperature changes. According to (6), the output characteristics of the MOS gate structure transistor are the same as the output characteristics of the current bipolar Darlington transistor, and a semiconductor device in which a circuit for suppressing the collector voltage oscillation immediately after the start of the current limitation is integrated.

According to (7), in the output characteristic of the MOS gate transistor of (6), in the current limiting region where the collector voltage is at least up to 16 V, the change of the collector current with respect to the collector voltage of 1 V is zero. .1
A semiconductor device that can suppress collector voltage oscillation by setting the resistance to A or more. In practice, it is difficult to suppress vibration below 0.1 A.

[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 withstand voltage constant current element 308 connected in series are connected between the collector and the gate. This combination corresponds to the configuration of claim 1. The high breakdown voltage constant current element 308 may use a MOSFET and an IGBT having a depletion structure, or may be built 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 function of the zener diode 312 may be shared. Alternatively, the high withstand voltage constant current element 308 may be a circuit such as a series power supply.

The constant current value of the high withstand voltage constant current element 308 and the value of the resistor 309 suppress the increase in the minute current flowing from the collector terminal to the gate terminal, which is the content of the third aspect. 12 (a) and 12 (b) show an example in which the collector voltage can be set. FIG. 3A shows the relationship between the gate-source voltage and the source-drain voltage and the drain current of the depletion-mode MOSFET. When the gate-drain voltage is zero, the drain current saturates at 2 mA, and becomes constant regardless of the source-drain voltage. Therefore, it functions as a constant current element. FIG. 3B shows that the value of the resistor R (corresponding to the resistor 309) is 3 k.
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 is shown. The collector voltage Vc at which the current value saturates becomes 2 mA is 6 V when the resistance R is 3 kΩ and 10 V and 8 k when it is 5 kΩ.
It is 16V when it is Ω. That is, the product of the resistance R and 2 mA is the collector voltage VC at which the minute current I is saturated.
Is changed, the collector voltage Vc can be changed. 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 voltage division of the resistor 306, the gate voltage increases as the collector voltage Vc increases, and the collector current also increases. Therefore, the output characteristics of the IGBT 303 are similar to the output characteristics of the bipolar Darlington transistor of 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, when the value of the resistor R is increased, the collector voltage Vc at which the minute current I is saturated can be increased, and the effect of suppressing the oscillation of the collector voltage can be enhanced. The value of the small current I may be 0.01 mA to 10 mA, and more practically 0.5 mA to 10 mA, and preferably about 1 mA to 3 mA. When the current value increases, the amount of energy stored in the ignition coil consumed by the current increases, and a spark voltage may not be secured. On the other hand, if it is too small, the output characteristic approaches the MOSFET characteristic from the bipolar Darlington transistor characteristic, and the collector voltage waveform oscillates. On the other hand, IGBT30
In order to turn off the ignition coil 3, shut off the ignition coil current, and discharge the spark plug with the energy stored in the ignition coil, it is necessary to maintain the voltage generated in the ignition coil at several hundred volts. For this purpose, the ignition coil current must be reduced as much as possible, and the value of the constant current flowing through the high withstand voltage constant current element must be as small as several mA even at a high voltage. That is, in this embodiment, the resistor 309 is inserted between the gate and the collector to make the output characteristic of the IGBT 303 the output characteristic of the bipolar Darlington transistor, and the high voltage constant current element 308 is connected to the resistor 309 to secure the spark voltage. They are connected in series. Further, a configuration of one of the resistor 309 and the high withstand voltage constant current element 308 is also conceivable. This is claimed in 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 circuit in which a resistor 208 and a capacitor 209 are connected in series 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. When the IGBT 203 is turned off, the capacitor 209 disconnects the IGBT 20 from the ignition coil 202.
3 absorbs the current that is about to flow to 3, and sharply decreases the current, and raises the voltage of the gate with the electric charge due to the minute current from the ignition coil 202, thereby ensuring the spark voltage. It works similarly to the breakdown voltage constant current element. Note that only the capacitor 209 may be used.

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 the effect of suppressing oscillation of the collector voltage. Further, the high withstand voltage constant current element 308 of FIG. 1 may be further 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 voltages of the GBTs 303 and 203 are single transistors and MOs.
Operation amplifier (operational amplifier) other than SFET
And the like can be used, and even these are effective. FIG. 8 is a diagram showing a circuit configuration of the third embodiment of the present invention. A resistor 410 corresponds to the resistor 208 of the first embodiment. When the IGBT 401 is turned off and the collector voltage becomes at least 25 V or higher, the resistor 410 is turned on.
This is an example of a circuit in the case where a very small current flowing through the MOSFET is cut off by a MOSFET 403. Drive circuit (with internal resistance, of course)
To the IGBT 401 from the IGBT 40
Turn 1 on. The IGBT 401 has a current detection terminal, and is commonly called a current sense IGBT. This current detection terminal is connected to a ground point via a resistor 405. The ignition coil current becomes a collector current and flows out through the IGBT 401. Then, the increased collector current is shunted to the current detection terminal, and the potential at the upper end of the resistor 405 is raised to turn on the MOSFET 402. At this time, the MOSFET 404 is connected to the IGBT4
01 is an off state because the collector-emitter voltage becomes extremely small. Then, the MOSFET 403 is turned on, the resistor 410 is connected to the gate terminal of the IGBT 401, and the minute current is supplied to the resistor 410 and the MOSFET 40.
3 through the MOSFET 402 and the IGBT 4
As the gate voltage of 01, a voltage generated by the on-resistance of the MOSFET 402 is applied. Collector current is MOSFET4
Finally, a constant current is obtained by the operation of 02. The resistor 41
By connecting 0 to the gate terminal of the IGBT 401, the output characteristic of the IGBT 401 is changed to the output characteristic of a bipolar Darlington transistor, thereby suppressing the oscillation of the collector voltage. Further, the MOSFET 403 is necessary to shut off a minute current from the ignition coil when the IGBT 401 is turned off, and to ensure a spark voltage.
Furthermore, although not shown, if an additional resistor is connected in parallel between the drain and the source of the MOSFET 403, an embodiment in which the above-described minute current is reduced at least when the collector voltage is 25 V or more is provided.

FIG. 9 is a diagram showing a circuit configuration of a 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 make 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 ET 503 corresponds to the MOSFET 403 of the third embodiment.

Operation amplifier (operational amplifier)
502 is an emitter terminal of the IGBT 501 and the MOSFET
A connection is made between the gate terminals of 504 via a resistor 507 so that the operation amplifier operates only during the application period of the gate voltage previously applied from the drive circuit 513 to the IGBT 501. FIG. 10 is a diagram showing a circuit configuration of a fifth embodiment of the present invention. Voltage detection circuit (monitor circuit) 6 for detecting and monitoring the voltage of ignition coil 602
08 is connected to both ends of the ignition coil 602, and the other is connected to the minute current circuit 609. The minute current circuit 609 is a minute current switch circuit 61.
1 is connected to the gate terminal of the IGBT 603. When the ignition coil voltage has a polarity opposite to the main circuit power supply voltage or a polarity that is added to the main circuit power supply voltage and the voltage drops by more than the gate voltage value, the voltage generated by the minute current from the minute current circuit to the gate terminal can be supplied to the collector. Suppresses voltage oscillation. The IGBT 603 has a current detection terminal. In the drawing, 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 an operating point where the temperature change of the transistor constituting the control device is small.
Here, an example in which a MOSFET is used as a transistor is shown. Of course, the circuit components (transistors 304 and 204, etc.,
FIG. 11 shows an example of reducing the temperature change at the operating point of the circuit 2 or the like. In FIG. 11, the temperature change of the current limit value can be reduced by setting the crossing point as the operating point.

FIG. 13 is an operation waveform diagram when the power MOSFET having the output characteristics shown in FIG. 5 is applied to the circuit of FIG. Since the output characteristics of the MOSFET become closer to the output characteristics of the bipolar Darlington transistor by installing the circuit of the present invention, the oscillation of the drain voltage shown in FIG. 3 has disappeared. In each of the above embodiments, IG
The BT, the current limiting circuit, and the minute current supply circuit can be configured on one chip. Further, it is possible to form a single chip including a driving circuit, or the individual elements may be mounted on a ceramic substrate or a metal insulating substrate and housed in a case to form a single package. Moreover, it is good also as one module including an ignition coil.

Although the present invention has been described with reference to the example in which the MOS gate structure transistor is applied to a circuit device for igniting an internal combustion engine, the present invention is not limited to this, but may be applied to a circuit including an inductive component in a wiring system. Has a remarkable effect. For example, the circuit device of the present invention can be used for 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
There is an 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 relates to an M transistor that enables high-speed switching with a lower driving current than a conventional bipolar Darlington transistor.
An OS gate transistor can be applied to an automobile ignition circuit. Secondly, it is possible to prevent sparks from being generated in the spark plug at unscheduled timing during the constant current operation of the ignition coil current of the MOS gate structure transistor having the first effect. Thirdly, it is possible to prevent the drain voltage from oscillating immediately after the start of the current limitation, which is a bad effect when a circuit for monitoring the drain voltage is added in order to monitor the operation state of the ignition system, which provides the first effect. Fourth, waveform oscillation during the entire current limiting operation is prevented. The above effects are obtained.

[Brief description of the 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 is a collector voltage / current waveform diagram at the time of current limitation in a bipolar Darlington transistor.

FIG. 3 is a collector voltage / current waveform diagram at the time of current limitation in a power MOSFET.

FIG. 4 is an output characteristic diagram of a bipolar Darlington transistor

FIG. 5 shows a power M with a withstand voltage of 250 V and an ON resistance of 0.16Ω
OSFET output characteristics

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 the setting of a collector voltage at which suppression of a minute current or a voltage applied to a gate terminal from a collector terminal is started.

FIG. 13 is a power MOSFET having the output characteristics of FIG.
Operation waveform diagram when is applied to the circuit of FIG.

[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
Driving circuit 110, 312 Zener diode 112, 209, 311, 607 Capacitor 203, 303, 501 IGBT 204, 402 to 404, 503 to 505, 604
MOSFET 308 High withstand voltage constant current element 313 Diode 401, 603 IGBT with current detection terminal 502 Operational amplifier 608 Monitor circuit 609 Microcurrent circuit 611 Microcurrent switch circuit

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-5-164031 (JP, A) JP-A-2-136563 (JP, A) JP-A-59-176929 (JP, A) JP-A-5-176929 195927 (JP, A) JP-A-5-18305 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02P 3/04 301 H01L 29/78

Claims (10)

(57) [Claims] A DC power supply and a switching means are connected to a primary winding of an ignition coil, an ignition plug is connected to one end of a secondary winding of the ignition coil, and a primary current of the ignition coil by opening and closing the switching means is provided. In the apparatus for supplying a high voltage generated in the secondary winding due to the change to the ignition plug, the switching means is a MOS gate structure transistor, and in order to limit the coil current of the primary winding to a certain value, at least a coil current detection unit And a circuit for lowering the gate voltage of the MOS gate structure transistor. When the main terminal voltage of the MOS gate structure transistor having a higher voltage value is higher than the gate terminal voltage, the main terminal voltage of the MOS gate structure transistor is reduced from the main terminal having the higher voltage value. A current supply circuit for applying a voltage generated by a current flowing into the gate terminal to the gate terminal; Engine ignition circuit device according to claim. 2. The ignition circuit device according to claim 1, wherein the current flowing from said main terminal to said gate terminal of said MOS gate transistor is 0.01 mA to 10 mA. Wherein said main terminal voltage is lower than or equal to a predetermined voltage, and, below the voltage value set in the range higher than the gate terminal voltage, a current flowing into the gate terminal of the main terminal The resulting voltage to a constant or previous
According to the difference between the serial main terminal voltage and the gate terminal voltage, as applied to the gate terminal, before higher than Ki設 boss was voltage value, the voltage generated by the current flowing from the front Symbol main terminal to the gate terminal 2. The ignition circuit device for an internal combustion engine according to claim 1, further comprising a circuit for suppressing, decreasing or cutting off the increase. 4. The method according to claim 1, wherein the value of the predetermined voltage is 20 V to 30 V.
4. The ignition circuit device according to claim 3, wherein: 5. The ignition device according to claim 1, further comprising a circuit for operating the current supply circuit during a period in which a gate voltage added in advance is applied. 6. A DC power supply and a switching means are connected to a primary winding of the ignition coil, a spark plug is connected to one end of a secondary winding of the ignition coil, and a primary current of the ignition coil by opening and closing the switching means is provided. In the apparatus for supplying a high voltage generated in the secondary winding due to the change to the ignition plug, the switching means is a MOS gate structure transistor, and in order to limit the coil current of the primary winding to a certain value, at least a coil current detection unit And a circuit for lowering the gate voltage of the MOS gate structure transistor, comprising: a detection circuit for detecting a voltage between both ends of the coil; a microcurrent circuit for applying a voltage generated by a microcurrent to a gate terminal; JP further comprising a circuit for operating the micro current circuit only while the voltage is applied Internal combustion engine ignition circuit device according to. 7. The gate voltage of a MOS gate structure transistor
The operating point of the pressure drop circuit does not change much with temperature
7. The method according to claim 1, wherein the point is set to a point.
The ignition circuit device according to any one of the above. 8. A circuit for ignition of an internal combustion engine according to claim 1 , wherein a part or all of a circuit excluding a DC power supply and an ignition coil is formed in one chip or one package. Semiconductor device for ignition of an internal combustion engine. 9. A gate voltage supplied from a drive circuit is fixed to a constant value within an output characteristic of a MOS gate structure transistor connected in series with an ignition coil within a range substantially equal to a current-limited coil current. In a region where the main terminal voltage changes rapidly from a region where the main terminal voltage hardly changes due to an increase in the main terminal current, the main terminal voltage is at least up to a first predetermined value. A semiconductor device for igniting an internal combustion engine, wherein a variation of a main terminal current with respect to an inter-voltage 1 V is equal to or more than a second predetermined value. 10. The semiconductor device for ignition of an internal combustion engine according to claim 9, wherein the first predetermined value is 16 V, and the second predetermined value is 0.1 A.