Semiconductor device and ignition control device equipped with the same

Abstract

To prevent an input determination circuit from misunderstanding an on operation by an electromotive force caused by parasitic inductance of ground wiring during an off period of a power semiconductor device used in the semiconductor device, and prevent vibration of a collector current caused by a re-on operation of a power semiconductor device.SOLUTION: A delay circuit is provided at an output of an input determination circuit, and when a signal output by the input determination circuit is an on operation determination signal, it is delayed during 10 μsec to 20 μsec, thereby masking an on operation determination signal of several μsec to prevent re-on operation of a power semiconductor device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor device and a circuit configuration of an ignition control device including the semiconductor device. [Background technology]

[0002] An igniter, which controls the current flowing through the ignition coil of an internal combustion engine, is equipped with power semiconductor elements such as insulated gate bipolar transistors (IGBTs), and controls the flow of primary current through the ignition coil by controlling the power semiconductor elements based on switching control signals from an engine control unit (ECU).

[0003] When the power semiconductor element is turned off, the voltage of the primary coil rises to several hundred volts, generating a high voltage of several tens of kV in the secondary coil according to the winding ratio of the primary coil and secondary coil, causing the spark plug to discharge.

[0004] Furthermore, as shown in Patent Document 1, for example, the igniter is provided with a resistor connected between the gate signal input terminal of the igniter and the gate terminal of the power semiconductor element, and a resistor connected between the gate signal input terminal of the igniter and the ground terminal (or emitter terminal), and the gate charge is extracted through these resistors when the power semiconductor is turned off.

[0005] Furthermore, as shown in Patent Document 1, for example, there is a technology in which a speed-up diode is provided from the gate terminal of the power semiconductor to the signal input terminal of the igniter, thereby quickly extracting the gate charge of the power semiconductor element when the power semiconductor element is turned off, thereby quickly turning off the power semiconductor element. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2018-7539 Summary of the Invention [Problem to be solved by the invention]

[0007] The sudden change in current when the power semiconductor element is turned off and the electromotive force caused by the parasitic inductance of the ground wiring cause the emitter potential of the igniter to drop relative to the ECU ground, causing the potential difference between the signal input terminal and emitter terminal of the igniter to increase. This causes problems such as the power semiconductor elements not being able to turn off properly, lengthening the turn-off time, or causing the collector current, which is equivalent to the primary coil current, to oscillate during the turn-off period, affecting the timing of the ignition coil discharge and generating noise that can affect other equipment inside the vehicle. The present invention has been made in consideration of the above-mentioned problems, and aims to provide a semiconductor device that can suppress the adverse effects caused by oscillations in the collector current of a power semiconductor element, and an ignition control device equipped with the same. [Means for solving the problem]

[0008] In order to solve the above problem, the present invention provides a semiconductor device having a power semiconductor element connected between a first terminal on the high potential side and a second terminal on the low potential side, a control terminal to which a switching control signal is input, a gate resistor connected between the gate of the power semiconductor element, and a cutoff unit connected between the gate of the power semiconductor element and the second terminal, an input judgment circuit that judges whether or not a potential difference between the control terminal potential and the second terminal potential is higher than a predetermined potential and outputs this judgment result as an input judgment signal, and a delay circuit that receives the input judgment signal and has an output connected to the input of the cutoff unit, and that, when the potential difference is higher than the predetermined potential (an on-judgment signal), outputs the input judgment signal with a predetermined delay from when the potential difference exceeds the predetermined potential, and an ignition control device equipped with the semiconductor device. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a semiconductor device capable of suppressing the adverse effects of oscillations in the collector current of a power semiconductor element, and an ignition control device including the semiconductor device. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a configuration example of a first embodiment of a semiconductor device according to the present invention and an ignition control device including the semiconductor device; [Figure 2] FIG. 2 is a diagram illustrating a configuration example of an input determination circuit. [Figure 3] FIG. 2 is a diagram illustrating an example of the configuration of a delay circuit. [Figure 4] 1 is a diagram illustrating an example of the configuration of a semiconductor device and an ignition control device including the semiconductor device according to a conventional technology; [Figure 5a] FIG. 1 is a diagram of operational waveforms of an embodiment of the prior art. [Figure 5b] FIG. 4 is a diagram showing operational waveforms according to the first embodiment. [Figure 6] FIG. 2 is a diagram illustrating an example of the configuration of a control signal generating unit. [Figure 7] FIG. 2 is a diagram illustrating a configuration example of a second embodiment of a semiconductor device according to the present invention and an ignition control device including the semiconductor device. [Figure 8] FIG. 10 is a diagram illustrating a configuration example of a third embodiment of a semiconductor device according to the present invention and an ignition control device including the semiconductor device. [Figure 9a] FIG. 10 is a diagram showing operational waveforms of the first embodiment in a state where the parasitic inductance of the emitter wiring is high. [Figure 9b] FIG. 10 is a diagram showing operational waveforms of the third embodiment in a state where the parasitic inductance of the emitter wiring is high. [Figure 10] FIG. 10 is a diagram illustrating a configuration example of a fourth embodiment of a semiconductor device according to the present invention and an ignition control device including the semiconductor device. [Figure 11] FIG. 10 is a diagram illustrating a configuration example of a fifth embodiment of a semiconductor device according to the present invention and an ignition control device including the semiconductor device. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1 to 3 show examples of the configuration of a first embodiment of a semiconductor device according to the present invention and an ignition control device including the same. Here, the semiconductor device of the present application may be a load driving device having inductance such as an igniter.

[0012] An ignition control device 1000 for an internal combustion engine of an automobile or the like comprises a control signal generating unit 10, an ignition plug 20, an ignition coil 30, a power supply 40, and a semiconductor device 100 according to the present invention.

[0013] The control signal generating section 10 generates a switching control signal Vin that controls the on / off switching of the power semiconductor element 110 built into the semiconductor device 100 .

[0014] The control signal generating unit 10 is, for example, a part or the whole of an ECU of an automobile.

[0015] When the control signal generating unit 10 supplies the switching control signal Vin to the semiconductor device 100 , the ignition control device 1000 for an internal combustion engine starts the ignition operation of the spark plug 20 .

[0016] The spark plug 20 generates an electrical spark by discharging. The spark plug 20 discharges when a voltage of, for example, about 10 kV or more is applied.

[0017] The spark plug 20 is provided, for example, in an internal combustion engine, and in this case, ignites combustion gas such as an air-fuel mixture in a combustion chamber.

[0018] The spark plug 20 is provided in, for example, a through hole that passes through from the outside of the cylinder to the combustion chamber inside the cylinder, and is fixed so as to seal the through hole. In this case, one end of the spark plug 20 is exposed to the combustion chamber, and the other end receives an electrical signal from outside the cylinder.

[0019] The ignition coil 30 supplies a high voltage as an electrical signal to the spark plug 20 to cause it to discharge.

[0020] The ignition coil 30 may function as a transformer, for example, an ignition coil having a primary coil 32 and a secondary coil 34 .

[0021] One end of the primary coil 32 and one end of the secondary coil 34 are electrically connected.

[0022] The primary coil 32 of the ignition coil 30 has fewer windings than the secondary coil 34 and shares a core with the secondary coil 34. The secondary coil 34 generates an electromotive force (mutually induced electromotive force) in response to the electromotive force generated in the primary coil 32.

[0023] The other end of the secondary coil 34 is connected to the spark plug 20, and supplies the generated electromotive force to the spark plug 20 to cause discharge.

[0024] The power supply 40 supplies a voltage to the ignition coil 30. The power supply 40 supplies, for example, a predetermined constant voltage Vb (for example, 14 V) to one end of the primary coil 32 and the secondary coil 34. For example, the power supply 40 is a car battery.

[0025] The semiconductor device 100 switches between conduction and non-conduction between the other end of the primary coil 32 of the ignition coil 30 and the reference potential in response to a switching control signal Vin supplied from the control signal generating unit 10.

[0026] For example, the semiconductor device 100 brings the primary coil 32 and the reference potential into conduction when the switching control signal Vin is at a high potential (on potential), and brings them into non-conduction when the switching control signal Vin is at a low potential (off potential).

[0027] Here, the reference potential may be a reference potential in the control system of the automobile, or may be a reference potential corresponding to the semiconductor device 100 inside the automobile. The reference potential may be a low potential that turns off the semiconductor device 100, and is, for example, 0 V.

[0028] The semiconductor device 100 includes a control terminal 102, a first terminal 104, a second terminal 106, a power semiconductor element 110, a cutoff unit 120, an input determination circuit 130, a delay circuit 140, a logic circuit 150, a gate resistor 170, a speed-up diode 180, and a pull-down resistor 190. The semiconductor device 100 has a configuration in which these components are integrated on a single semiconductor substrate.

[0029] In addition, the power supply voltage that operates the input determination circuit 130 and the delay circuit 140 is also the switching control signal Vin input from the control terminal 102, and the input determination circuit 130 and the delay circuit 140 are configured to operate only when the switching control signal Vin is at a high potential.

[0030] The control terminal 102 is connected to the control signal generating unit 10 and receives a switching control signal Vin for controlling the power semiconductor element 110. The first terminal 104 is connected to the power supply 40 via the ignition coil 30.

[0031] The second terminal 106 is connected to a reference potential. That is, the first terminal 104 is a terminal on the higher potential side compared to the second terminal 106, and the second terminal 106 is a terminal on the lower potential side compared to the first terminal 104.

[0032] The power semiconductor element 110 includes a gate terminal, a collector terminal, and an emitter terminal, and the gate is controlled in response to a switching control signal Vin input to the gate terminal to electrically connect or disconnect the collector terminal and the emitter terminal.

[0033] The power semiconductor element 110 is connected between a first terminal 104 on the high potential side and a second terminal 106 on the low potential side, and is controlled to be on or off according to the gate potential.

[0034] The power semiconductor element 110 is, for example, an IGBT, or may be a metal oxide semiconductor field effect transistor (MOSFET). In the case of a MOSFET, the collector terminal can be read as the drain terminal, and the emitter terminal as the source terminal.

[0035] The emitter terminal of the power semiconductor element 110 is connected to the second terminal 106, and the collector terminal is connected to the first terminal 104.

[0036] In this embodiment, an example will be described in which the power semiconductor element 110 is an IGBT that electrically connects the collector terminal and the emitter terminal in response to the switching control signal Vin becoming high potential.

[0037] First, we will explain the basic operation of the semiconductor device 100. In the turn-on operation, which turns on the power semiconductor element 110 and conducts the primary coil current, when a high potential is input to the switching control signal Vin, a high potential equal to or higher than the threshold voltage of the power semiconductor element 110 is applied to the gate terminal of the power semiconductor element 110 via the gate resistor 170, turning on the power semiconductor element 110 and starting to flow the primary coil current.

[0038] On the other hand, when a low potential is input to the switching control signal Vin, the charge at the gate terminal of the power semiconductor element 110 is discharged to the reference potential via the gate resistor 170, the speed-up diode 180, and further via the pull-down resistor 190. As a result, the gate potential of the power semiconductor element 110 drops to a low potential that is equal to or lower than the threshold voltage of the power semiconductor element, the power semiconductor element 110 turns off, and the primary-side coil current is cut off.

[0039] In addition to the above basic operation, the semiconductor device 100 of FIG. 1 includes an input determination circuit 130, a delay circuit 140, a logic circuit 150, and a cutoff unit 120. The cutoff unit 120 is connected between the gate terminal of the power semiconductor element 110 and a reference potential. As an example, the cutoff unit 120 is an n-channel MOSFET that is controlled to turn on or off between the drain terminal and the source terminal in response to a cutoff unit input signal Vmos, which is the gate potential.

[0040] The cutoff unit 120 is, for example, a normally-off switch element that electrically connects the drain terminal and the source terminal in response to the cutoff unit input signal Vmos, which is the gate potential, becoming a high potential.

[0041] The cutoff unit 120 has a drain terminal connected to the gate terminal of the power semiconductor element 110, a source terminal connected to a reference potential, and switches whether or not to supply the switching control signal Vin input from the control terminal 102 to the gate terminal of the power semiconductor element 110 depending on whether the cutoff unit input signal Vmos input to the gate terminal is high potential or low potential.

[0042] The gate resistor 170 is connected between the control terminal 102 and the gate terminal of the power semiconductor device 110 .

[0043] When the cutoff unit 120 is in the off state, the gate resistor 170 supplies the switching control signal Vin to the gate terminal of the power semiconductor element 110. When the cutoff unit 120 is in the on state, the switching control signal Vin flowing in via the gate resistor 170 flows to the reference potential via the cutoff unit 120, and a low potential is applied to the gate terminal of the power semiconductor element 110.

[0044] Furthermore, when the cutoff unit 120 is in the ON state, the gate voltage of the power semiconductor element 110 is discharged to the reference potential via the cutoff unit 120. That is, the power semiconductor element 110 is in the OFF state.

[0045] The input determination circuit 130 is connected between the control terminal 102 and the delay circuit 140 .

[0046] The input determination circuit 130 receives the control terminal potential Vg and the emitter potential Ve from the control signal generating unit 10 as inputs and makes a determination. If the difference between the control terminal potential Vg and the emitter potential Ve is equal to or greater than a predetermined potential, it determines that the signal is an on signal for the power semiconductor element, and outputs an on determination signal as the input determination signal Vj. If the difference between the control terminal potential Vg and the emitter potential Ve is lower than the predetermined potential, it determines that the signal is an off signal for the power semiconductor element, and outputs an off determination signal as the input determination signal Vj. The input determination signal Vj is transmitted to the cutoff unit 120 via the delay circuit 140 and the logic circuit 150. Here, the predetermined potential is, for example, the threshold potential of the power semiconductor element. In this example, the on determination signal is a high-level signal, and the off determination signal is a low-level signal.

[0047] An example of the configuration of the input determination circuit 130 is shown in FIG.

[0048] The input determination circuit 130 includes resistors 131 and 132 connected in series between the control terminal 102 and the second terminal 106, and a resistor 133 and a MOSFET 134 arranged in series with each other and in parallel with the resistors 131 and 132. The input determination circuit 130 further includes a plurality of inverters 135 whose inputs and outputs are connected in series between one end of the resistor 133 and the collector of the MOSFET 134.

[0049] A wire extending from the connection point between the resistors 131 and 132 is connected to the gate of the MOSFET 134 .

[0050] Furthermore, the input of one of the inverters 135 is connected to the connection point between one end of the resistor 133 and the drain of the MOSFET 134 , and the output of one of the inverters is connected to the input terminal of the delay circuit 140 .

[0051] Generally, the semiconductor device 100 is integrated with the ignition coil 30, and the control terminal 102, the second terminal 106, and the terminal corresponding to the power supply 40 side connection terminal of the ignition coil 30 are connected to the signal output terminal of the ECU, the reference potential, and the battery terminal, or to the corresponding connection terminals, via a harness. Depending on the length of this harness, the parasitic inductance between the second terminal 106 and the reference potential is expected to be approximately 5 μH at maximum.

[0052] When the switching control signal Vin input to the control terminal 102 becomes an OFF signal and the IGBT, which is the power semiconductor element 110, turns OFF, the potential of the second terminal 106 drops by a voltage value determined by the slope of the collector current Ic and the parasitic inductance value of the harness, and as a result, the potential difference between the control terminal 102 and the second terminal 106 rises, and depending on the rising potential, it becomes an input signal equivalent to when an ON signal is input from the switching control signal Vin, and if the semiconductor device 100 operates in response to this signal, it will interfere with the turn-OFF operation. The rise time is approximately several μsec.

[0053] Although the plurality of inverters 135 of the input determination circuit 130 also have the effect of delaying the input signal, they do not have the ability to mask the ON determination signal for several microseconds.

[0054] The delay circuit 140 receives the input determination signal Vj output from the input determination circuit 130, has its output connected to the input of the logic circuit 150, and outputs a delay circuit output signal Vd.

[0055] When the input determination signal Vj output from the input determination circuit 130 to the logic circuit 150 is an ON determination signal, the delay circuit 140 can delay this by 10 μsec to 20 μsec from the reception of the ON determination signal.

[0056] An example of the configuration of the delay circuit 140 is shown in FIG.

[0057] The delay circuit 140 includes a resistor 141 connected to the output of the input determination circuit 130, a capacitor 142 to which current is supplied via the resistor 141, and a plurality of inverters 143 connected to the connection point between the resistor 141 and the capacitor 142, with their inputs and outputs connected in series.

[0058] One end of the resistor 141 is connected to the output of the input determination circuit 130, and the other end is connected to the capacitor.

[0059] The input of one of the plurality of inverters 143 is connected to the connection point between the resistor 141 and the capacitor 142 , and the output of one of the plurality of inverters 143 is connected to the input terminal of the cutoff unit 120 .

[0060] The delay circuit 140 smooths out temporary rises and falls in the input potential by using the charging and discharging effect of the capacitor 142, and outputs the smoothed potential. By adjusting the capacitance of the capacitor 142, the delay time can also be adjusted.

[0061] The logic circuit 150 is a device that converts the delay circuit output signal Vd output from the delay circuit 140 into the cutoff unit input signal Vmos, and in this embodiment, an inverter circuit is used.

[0062] In the semiconductor device 100 according to the present embodiment, when the power semiconductor element 110 is in a normal state and the switching control signal Vin changes from a high potential to a low potential, the power semiconductor element 110 changes from an on state to an off state.

[0063] As a result, the collector current Ic that has been flowing from the power supply 40 through the primary coil 32 of the ignition coil 30 decreases rapidly.

[0064] When the switching control signal Vin is applied at a high potential to the control terminal 102, the time change dIc / dt of the collector current Ic is determined according to the inductance of the primary coil 32 and the supply voltage of the power supply 40, and the collector current Ic maintains a predetermined (or set) current value according to the on-time.

[0065] For example, the collector current Ic is about several amperes, a dozen amperes, or several tens of amperes in the on state.

[0066] Due to the sudden decrease in collector current in the off state, the voltage across the primary coil 32 increases suddenly due to self-induced electromotive force, generating an induced electromotive force of up to several tens of kV across the voltage across the secondary coil 34.

[0067] The ignition control device 1000 supplies the voltage of the secondary coil 34 to the spark plug 20, thereby causing the spark plug 20 to discharge and ignite the combustion gas.

[0068] FIG. 5b shows the operational waveforms of the various parts of the semiconductor device 100 during the process in which the power semiconductor element 110 changes from the ON state to the OFF state. The operating waveforms will be explained with reference to FIG. 6, which shows an example of the output circuit configuration of the control signal generating section 10 in FIG.

[0069] At time T4, the command signal (CPU output signal) CPUout from the CPU 710 in the control signal generating unit 10 changes from high potential to low potential, turning off the transistor 720, and the switching control signal Vin discharges the capacitor 730, causing the potential to gradually decrease.

[0070] Since this switching control signal Vin also serves as the power supply voltage for the input determination circuit 130, the input determination signal Vj, which is the output voltage of the input determination circuit 130, also drops in response to the switching control signal Vin, and when the switching control signal Vin falls below the determination voltage of the input determination circuit 130, the input determination signal Vj outputs a low potential as an off determination signal.

[0071] Furthermore, when the switching control signal Vin begins to decrease, the gate charge of the power semiconductor element 110 begins to be discharged to the pull-down resistor 190 via the speed-up diode 180 .

[0072] When the input determination signal Vj outputs an OFF determination signal, the delay circuit output voltage Vd also outputs a low potential, the cutoff unit input signal Vmos, which is the output voltage of the logic circuit 150, becomes a high potential, and the cutoff unit 120 becomes conductive. The gate charge of the power semiconductor element 110 also begins to be discharged via the cutoff unit 120, accelerating the discharge of the gate charge.

[0073] From time T5 when the gate potential of the power semiconductor element 110 drops to near the threshold voltage of the power semiconductor element 110, the collector current Ic starts to drop, and the emitter potential Ve drops sharply due to -dIc / dt and parasitic inductance. As a result, the voltage between the control terminal 102 and the emitter potential Ve rises, and the input determination circuit 130 mistakenly determines that a high potential has been input from the switching control signal Vin, outputs an ON determination signal, and the conduction of the cutoff unit 120 is cut off.

[0074] As a result, the magnitude relationship between the control terminal 102 side and the gate potential of the power semiconductor element 110 changes, the discharge rate of the electric charge slows down, or the gate of the power semiconductor element 110 is charged again, the decrease in the collector current Ic slows down, and the decrease in the emitter potential Ve starts to increase. The voltage between the control terminal 102 and the emitter potential Ve decreases again, and the input determination circuit 130 outputs the OFF determination signal again, causing the cutoff unit 120 to become conductive, and accelerating the turning off of the power semiconductor element 110.

[0075] By repeating this operation, the power semiconductor element repeatedly turns on and off during the period T5 to T6 as shown in FIG. 5b, and the collector voltage Vc and collector current Ic oscillate in a cycle of several microseconds.

[0076] In the present invention, by providing the delay circuit 140, even if the input judgment signal Vj, which is the input signal to the delay circuit, starts to rise due to a drop in the emitter potential Ve, as shown in FIG. 5b, the delay circuit 140 delays the signal by 10 μsec to 20 μsec, and attempts to maintain the conductive state of the cutoff section 120. As a result, the power semiconductor element 110 also continues to maintain gate discharge, and oscillations in the collector voltage Vc and collector current Ic can be suppressed.

[0077] As described above, the role of pull-down resistor 190 in this application is to draw out the gate charge of power semiconductor element 110 and the charge of capacitor 730. Therefore, if the gate charge of power semiconductor element 110 can be completely drawn out by cut-off unit 120 and control signal generating unit 10 does not have capacitor 730, pull-down resistor 190 may not be necessary.

[0078] 4 shows an example of an ignition control device for an internal combustion engine according to a reference example, and an ignition control device 10000 equipped with the same. A semiconductor device 900 constituting the ignition control device 10000 has a power semiconductor element 910, a gate pull-down circuit (interrupter) 920 connected to the gate terminal of the power semiconductor element 910, gate resistors 912 and 970 connected between a control terminal 902 and the gate terminal of the power semiconductor element 910, a pull-down resistor 990, and a speed-up diode 980.

[0079] The semiconductor device 900 is composed of two chips: a power semiconductor chip 911 including a power semiconductor element 910, a gate resistor 912, etc., and a control semiconductor chip 921 including a cutoff section 920, an input determination circuit 930, a gate control circuit 950, etc.

[0080] When the signal input to control terminal 902 is an off-determination signal, the charge on the gate capacitance of power semiconductor element 910 is extracted via speed-up diode 980 and pull-down resistor 990. Also, cutoff unit 920 establishes conduction between the gate and emitter of power semiconductor element 910. This extracts charge from the gate capacitance of power semiconductor element 910, rapidly lowering the gate potential and cutting off the collector current.

[0081] By drawing out the gate charge by the cutoff section 920, the power semiconductor device 910 can be turned off rapidly.

[0082] The faster the power semiconductor element 910 turns off, the more rapidly the emitter potential Ve drops, causing the input determination circuit 930 to erroneously recognize the power semiconductor element 910 as on, which turns the power semiconductor element 910 on again. When the power semiconductor element 910 turns on, the potential difference Vge between the control terminal and the second terminal drops, and when the input determination circuit 930 recognizes the power semiconductor element 910 as an off signal, the power semiconductor element 910 turns off. Repeating these events causes the collector current to oscillate.

[0083] This vibration has adverse effects such as affecting the timing of discharge of secondary coil 834 of ignition coil 830, generating noise that affects other devices, and increasing losses.

[0084] FIG. 5a shows the operating waveforms of the various parts of the semiconductor device 900 when the power semiconductor element 910 changes from an ON state to an OFF state.

[0085] At time T1, the switching control signal Vin changes from high to low, causing the input determination circuit 930 to stop operating and the input determination signal Vj to drop. As a result, at time T2, the cutoff unit input signal Vmos rises, the cutoff unit 920 becomes conductive, and the collector current Ic begins to drop. During the period T2 to T3, the emitter potential Ve oscillates in a cycle of several microseconds due to -dIc / dt and parasitic inductance. Similarly, the potential difference Vge between the control terminal and the second terminal oscillates, causing the input determination circuit 930 to mistakenly recognize this as an ON signal for the power semiconductor element 910. As a result, the output input determination signal Vj also oscillates, causing the cutoff unit 920 to shut off and turn on the power semiconductor element 910. After this, the power semiconductor element 910 repeatedly turns on and off, causing the collector voltage Vc to oscillate, and the collector current Ic to oscillate slightly.

[0086] FIG. 7 shows a configuration example of a second embodiment 1001 of a semiconductor device according to the present invention and an ignition control device including the same.

[0087] The difference between the ignition control device 1001 and the ignition control device 1000 of the first embodiment is that the semiconductor device 200 is configured from two chips: a control semiconductor chip 101 and a power semiconductor chip 111. Even with this configuration, the same effects as in the first embodiment can be achieved.

[0088] Similarly, in the following embodiments, the semiconductor devices 300, 400, and 500 can each have a two-chip configuration.

[0089] FIG. 8 shows a configuration example of a third embodiment 1003 of a semiconductor device according to the present invention and an ignition control device including the same.

[0090] The difference between the ignition control device 1003 and the ignition control device 1000 of the first embodiment is that the speed-up diode 180 inside the semiconductor device 300 is eliminated and a backflow prevention diode 181 is provided. The other configurations are the same as those of the semiconductor device 100.

[0091] The diode 181 is connected between the control signal generating section 10 and the gate of the power semiconductor element 110, with the anode connected to the control signal generating section 10 side and the cathode connected to the power semiconductor element 110 side.

[0092] The pull-down resistor 190 can also serve as a path for extracting gate charge during the off period of the power semiconductor element 110. Therefore, in order to reliably extract the gate charge from the cutoff unit 120, a diode 181 is installed to prevent the gate charge of the power semiconductor element 110 from flowing back into the pull-down resistor 190.

[0093] Figure 9b shows the operating waveforms of each part of semiconductor device 300 as power semiconductor element 110 changes from the on state to the off state. For comparison, Figure 9a shows the operating waveforms of semiconductor device 100. Here, to show the difference between the two, the case where the parasitic inductance of the emitter wiring is higher than in Figures 5a and 5b is shown.

[0094] The phenomena occurring between times T1 and T6 are similar to those shown in Figures 5a and 5b. However, because the parasitic inductance of the emitter wiring is large, the drop in emitter potential Ve at turn-off is large, and the rise in switching control signal Vin is also large. In Figure 9a, which corresponds to the operational waveform diagram of semiconductor device 100, the input determination circuit 130 and delay circuit are unable to suppress the oscillations, and cutoff unit 120 cannot maintain a conductive state. As a result, the discharge rate of the gate charge of power semiconductor element 110 slows down temporarily, causing a drop in collector voltage Vc and slight oscillations in collector current Ic.

[0095] 9b, which corresponds to the operational waveform diagram of semiconductor device 300, the presence of diode 181 increases the impedance from the gate terminal of power semiconductor element 110 to control terminal 102, so even if a turn-off signal is input, the gate charge of power semiconductor element 110 is not discharged to the pull-down resistor side, and when the switching control signal Vin drops sufficiently and the input determination circuit detects off, cutoff unit 120 becomes conductive and begins to draw the gate charge of the power semiconductor element. During this period, the switching control signal Vin continues to drop, and at timing T5 when the gate voltage falls below the threshold voltage of power semiconductor element 110, the collector current Ic starts to drop.

[0096] At this time, the slope of the collector current Ic and the parasitic inductance cause the Ve voltage to decrease and the switching control signal Vin to increase, but since the switching control signal Vin at the start of current interruption is lower than at timing T2 in Figure 9a and does not exceed the judgment voltage of the input judgment circuit, it does not result in a false detection of an on signal, the interrupter 120 maintains conduction, and the power semiconductor element 110 is able to interrupt the current without vibrating.

[0097] FIG. 10 shows a configuration example of a fourth embodiment of a semiconductor device according to the present invention and an ignition control device including the semiconductor device.

[0098] The difference between the semiconductor device 400 of the ignition control device 1004 of this embodiment and the semiconductor device 300 is that the semiconductor device 400 does not have the diode 181 and has a very large resistance value of the gate resistor 170. The other configurations are the same as those of the semiconductor device 300.

[0099] The interrupter section 120 has an impedance, and the resistance value of the gate resistor 170 is preferably five times or more the impedance of the interrupter section 120 .

[0100] By setting the resistance value of the gate resistor 170 to be sufficiently large, the impedance from the gate terminal of the power semiconductor element 110 to the control terminal 102 is increased, as in the third embodiment, thereby suppressing the withdrawal of gate charge from the power semiconductor element 110 by the pull-down resistor, and the charge is withdrawn by the cut-off unit 120 once the Vin voltage has dropped sufficiently.

[0101] FIG. 11 shows a configuration example of a fifth embodiment of a semiconductor device according to the present invention and an ignition control device including the same.

[0102] The difference between semiconductor device 500 of ignition control device 1005 and semiconductor device 300 is that semiconductor device 500 has a series circuit of gate resistor 170 and backflow prevention diode 181 in parallel with second gate resistor 171 between control terminal 102 and the gate of power semiconductor element 110. Here, the resistance value of second gate resistor 171 is preferably five times or more the impedance of cutoff section 120. The other configurations are the same as those of semiconductor device 300.

[0103] The gate resistor 170 of the fourth embodiment and the second gate resistor 171 shown in the fifth embodiment increase the impedance from the gate terminal of the power semiconductor element 110 to the control terminal 102 at the time of turn-off, thereby suppressing the pull-down resistor 190 from extracting the gate charge of the power semiconductor element 110, and allowing the cut-off unit 120 to extract the charge once the Vin voltage has dropped sufficiently.

[0104] In the fourth embodiment shown in Fig. 10, if the resistance value of the gate resistor 170 is made too large, a problem occurs in that the delay time when turning on the power semiconductor element 110 becomes too long. In contrast, in the fifth example shown in Fig. 11, during the on period, the gate of the power semiconductor element 110 is charged via the gate resistor 170 and the diode 181, and during the off period, a second gate resistor 171 is provided so that most of the gate charge of the power semiconductor element 110 is extracted from the cutoff section 120, thereby reducing the increase in delay time when turning on the power semiconductor element 110.

[0105] As described above, in this embodiment, even if the emitter potential drops with respect to the ECU ground when the power semiconductor element is rapidly turned off and the gate-emitter potential difference increases, the malfunction of the power semiconductor element is suppressed by providing a delay circuit. This makes it possible to suppress the adverse effects of oscillations in the collector current of the power semiconductor element.

[0106] The embodiment of the present application is not limited to this, and for example, the blocking unit 120 may be a p-type MOSFET and the inverter of the logic circuit 150 may be eliminated. Also, the semiconductor device 100 does not have to be configured on the same semiconductor substrate. [Explanation of symbols]

[0107] 10...Control signal generating unit 20...Spark plug 30...Ignition coil 32...Primary coil 34...Secondary coil 40...Power supply 100...Semiconductor device (first embodiment) 102...Control terminal 104…1st terminal 106…Second terminal 110...Power semiconductor element 120...Interrupter 130...Input determination circuit 131, 132, 133...Resistor 134...MOSFET 135...Inverter 140...Delay circuit 141... Constant current source 142...Capacitor 143...Inverter 150...Logic circuit 170...Gate resistor 171...Second gate resistor 180...Speed-up diode 181...Diode 190...Pull-down resistor 1000... Ignition control device including the semiconductor device of the first embodiment 101...control semiconductor chip of semiconductor device (second embodiment) 111...power semiconductor chip of semiconductor device (second embodiment) 1001... Ignition control device including the semiconductor device of the second embodiment 200...Semiconductor device (second embodiment) 300...Semiconductor device (third embodiment) 1003... Ignition control device including the semiconductor device of the third embodiment 400...Semiconductor device (fourth embodiment) 1004...Ignition control device including the semiconductor device of the fourth embodiment 500...Semiconductor device (fifth embodiment) 1005...Ignition control device including the semiconductor device of the fifth embodiment 710...CPU 720...PNP transistor 730...Capacitor 820...Spark plug (example of conventional technology) 830...Ignition coil (example of conventional technology) 832...Primary coil (example of conventional technology) 834...Secondary coil (example of conventional technology) 840...Power supply (example of conventional technology) 900...Semiconductor device (prior art example) 902...Control terminal (example of prior art) 904...Collector terminal (example of conventional technology) 910...Power semiconductor element (example of conventional technology) 911...Power semiconductor chip (example of conventional technology) 912...Gate resistor (prior art example) 920...Interrupter (example of conventional technology) 921...Control semiconductor chip (example of prior art) 930...Input judgment circuit (example of prior art) 950...Gate control circuit (example of prior art) 970...Resistor (prior art example) 980...Speed-up diode (example of conventional technology) 990...Pull-down resistor (example of conventional technology) 10000...Example of ignition control device (prior art example) CPUout: CPU output signal Vg: Control terminal potential Ve: Emitter potential Vin: Switching control signal Vj: Input judgment signal Vd: Delay circuit output signal Vmos: Cutoff input signal Ic: Collector current

Claims

1. a power semiconductor element connected between a first terminal on a high potential side and a second terminal on a low potential side; a pull-down resistor connected between a control terminal to which a switching control signal is input and the second terminal; a gate resistor and a reverse current prevention diode are connected between the control terminal and the gate of the power semiconductor element to form a series circuit, and a second gate resistor is connected in parallel to the series circuit; the anode of the reverse current prevention diode is connected to the control terminal side and the cathode is connected to the gate side of the power semiconductor element, a cutoff portion connected between the gate of the power semiconductor element and the second terminal; an input determination circuit that determines whether a potential difference between the potential of the control terminal and the potential of the second terminal is higher than a predetermined potential and outputs the determination result as an input determination signal, wherein the input determination circuit outputs an ON determination signal as the input determination signal when the potential difference is higher than the predetermined potential, and further comprises a delay circuit that receives the input of the input determination signal, has an output connected to the input of the cutoff unit, and outputs the ON determination signal with a predetermined delay time from the time of input; Semiconductor device.

2. The resistance value of the gate resistor is 5 times or more the impedance of the cutoff section. The semiconductor device according to claim 1 .

3. The resistance value of the second gate resistor is five times or more the impedance of the cutoff section. The semiconductor device according to claim 1 .

4. the delay circuit includes a resistor and a capacitor connected in series between the output of the input determination circuit and the second terminal. The semiconductor device according to claim 1 .

5. the delay time in the delay circuit is 10 μsec to 20 μsec from the time when the ON determination signal of the input determination signal is received; The semiconductor device according to claim 1 .

6. the power semiconductor element, the pull-down resistor, the first gate resistor, the second gate resistor, the reverse current prevention diode, the cutoff unit, and the delay circuit are formed within the same chip. The semiconductor device according to claim 1 .

7. The semiconductor device is an igniter of an ignition control device of an internal combustion engine. The semiconductor device according to claim 1 .

8. 7. An ignition control device for an internal combustion engine, comprising the semiconductor device according to claim 1 as an igniter.

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