JP2020124091A - controller - Google Patents

Abstract

To provide a controller in which noise generated at turn-on and/or turn-off of a PWM gate voltage can be protected from affecting timing of the turn-on and/or turn-off of the PWM temperature voltage.SOLUTION: A controller is used while being connected a semiconductor device comprising an input terminal of gate voltage and an output terminal of a temperature-dependent voltage. The controller comprises: an output circuit of a PWM gate voltage that outputs a PWM gate voltage to be applied to an input terminal of the gate voltage; and an output circuit of a PWM gate voltage that outputs a PWM temperature obtained by modulating the temperature-dependent voltage. In the controller, the ratio between the period of the PWM gate voltage and the period of the PWM temperature voltage is set to be a non-integer value. It is difficult to match the timing of the turn-on and/or turn-off of the PWM gate voltage with the timing of the turn-on and/or turn-off of the PWM temperature voltage since the period ratio is set to be a non-integer value.SELECTED DRAWING: Figure 2

Description

The technology disclosed in this specification relates to a controller of a semiconductor device. In particular, the invention relates to a controller used by connecting to a semiconductor device having a gate voltage input terminal and a temperature dependent voltage output terminal.

2. Description of the Related Art There is known a semiconductor device that has a built-in transistor in which the resistance between a pair of main electrodes changes depending on the level of a gate voltage and that has a gate voltage input terminal. A semiconductor device having a temperature detecting function is also known. The semiconductor device of Patent Document 1 is provided with a temperature detection element that outputs a voltage that changes depending on temperature. The semiconductor device of Patent Document 1 includes an input terminal of a gate voltage and an output terminal of a temperature dependent voltage, the input terminal of the gate voltage is connected to a gate electrode, and the output terminal of the temperature dependent voltage is a temperature detecting element. It is connected.
When an analog voltage that changes depending on the temperature is applied to the wiring extending from the temperature-dependent voltage output terminal to the outside of the semiconductor device, noise generated from peripheral circuits is likely to be duplicated on the wiring. In Patent Document 1, the analog voltage is PWM-modulated, and a pulse wave (referred to as PWM temperature voltage) modulated so that its duty ratio is proportional to the analog voltage is sent to the gate voltage output circuit side. This shortens the wiring length for transmitting the analog voltage, making it less susceptible to noise.
The gate voltage output circuit controls on/off of the transistor in consideration of the temperature of the semiconductor device. For example, when it is necessary to protect a semiconductor device from overheating, the on-time is shortened and the off-time is lengthened. The gate voltage output circuit applies a PWM-modulated pulse wave (referred to as a PWM gate voltage) to a gate voltage input terminal to control ON/OFF of the transistor.

International Publication No. 2015/076014

When the gate voltage output circuit outputs the PWM gate voltage to the gate voltage input terminal, noise may be generated at turn-on and turn-off timings. This noise overlaps the analog voltage. That is, the timing at which the noise overlaps the analog voltage changes depending on the cycle of the PWM gate voltage.
Here, the cycle of the PWM gate voltage may be changed depending on the magnitude of the change per unit time of the voltage output by the device switched by the semiconductor device. Specifically, when there is a large change in the voltage output from the device per unit time, the trackability is improved by shortening the cycle of the PWM gate voltage. On the other hand, when the change in the voltage output from the device per unit time is small, the cycle is lengthened to reduce noise due to switching. On the other hand, the cycle of the PWM temperature voltage may be kept constant. In such a case, in the technique disclosed in Patent Document 1, the cycle of the PWM gate voltage may change and become the same as the cycle of the PWM temperature voltage, or there may be a multiplication relationship.

If the period of the PWM gate voltage and the period of the PWM temperature voltage are the same or have a multiplication relationship, the turn-on timing and/or turn-off timing of the PWM gate voltage coincides with the turn-on timing and/or turn-off timing of the PWM temperature voltage. It will be easier. In this case, the analog voltage that changes depending on the temperature of the semiconductor device disturbs the relationship in which the turn-on timing and/or turn-off timing of the PWM temperature voltage is determined, and the analog voltage occurs when the PWM gate voltage is turned on and/or turned off. The noise-overlapping voltage will determine the turn-on and/or turn-off timing of the PWM temperature voltage. As a result, the duty ratio of the PWM temperature voltage may not be proportional to the analog voltage that changes depending on the temperature of the semiconductor device.
Provided herein is a controller in which the PWM gate voltage turn-on and/or turn-off timing is difficult to match the PWM temperature voltage turn-on and/or turn-off timing.

The controller disclosed in this specification is used by being connected to a semiconductor device having a gate voltage input terminal and a temperature-dependent voltage output terminal.
The controller also includes a PWM gate voltage output circuit that outputs a PWM gate voltage applied to a gate voltage input terminal, and a PWM temperature voltage output circuit that outputs a PWM temperature voltage obtained by modulating a temperature-dependent voltage.
Further, in this controller, the ratio of the cycle of the PWM gate voltage and the cycle of the PWM temperature voltage is set to a non-integer.

In the controller described above, since the ratio of the period of the PWM gate voltage and the period of the PWM temperature voltage is set to a non-integer, the turn-on and/or turn-off timing of the PWM gate voltage is set to the turn-on and/or turn-on of the PWM temperature voltage. It is difficult to match the turn-off timing. As a result, it is possible to prevent noise generated when the PWM gate voltage is turned on and/or turned off from affecting the turn-on and/or turn-off timing of the PWM temperature voltage.

Details of the technology disclosed in the present specification and further improvements will be described in the following “Description of Embodiments”.

It is a block diagram of the electric equipment containing the controller of an Example. It is a wave form diagram which shows the relationship between a PWM gate voltage and a PWM temperature voltage. It is an enlarged view which shows the range of III in FIG. It is an enlarged view which shows the range of IV in FIG.

FIG. 1 shows a block diagram of an electronic device 1 including a controller 10 of the embodiment. The electronic device 1 constitutes a three-phase inverter that performs power conversion between DC power and three-phase AC power. FIG. 1 shows only a transistor 4 forming an upper arm of a U phase among the three phases (U phase, V phase, W phase). Actually, the transistors also include a U-phase lower arm, a V-phase upper arm, a V-phase lower arm, a W-phase upper arm, and a W-phase lower arm, which are not shown. The transistor forming the upper arm is connected to the positive electrode of the battery (not shown) through the high voltage side terminal 8a and the high voltage side wiring (not shown). The transistor forming the lower arm (not shown) is connected between the low voltage side terminal 8b and a ground line (not shown). A controller 10 is prepared for each transistor 4. In FIG. 1, only one transistor 4 and one controller 10 are shown.
It should be noted that the electronic device 1 is not limited to the inverter, and can be used in other types of power conversion devices such as a DC-DC converter. The electronic device 1 is not particularly limited, but can be adopted in a vehicle whose wheels are driven by a motor, such as a hybrid vehicle, a fuel cell vehicle, or a rechargeable electric vehicle.

As shown in FIG. 1, the electronic device 1 includes a semiconductor device 2 and a controller 10. The semiconductor device 2 includes a switching element (transistor) 4 and a temperature detection element 6. The switching element 4 includes a gate electrode 4g, and the gate electrode 4g is connected to the controller 10 via the gate voltage input terminal 4a. The switching element 4 is an IGBT (Insulated Gate Bipolar Transistor). The temperature detection element 6 is a diode. The anode of the temperature detection element 6 is connected to the controller 10 via the terminal 6a. As will be described later, the voltage of the terminal 6a changes depending on the temperature of the switching element 4. The terminal 6a is an output terminal for the temperature dependent voltage.
As will be described later in detail, a constant current flows through the temperature detection element 6 by the constant current circuit 20, and the voltage of the terminal 6a that outputs the temperature-dependent voltage changes depending on the temperature of the semiconductor device 2. Voltage. The terminal 6a is a terminal that outputs a temperature-dependent voltage. The semiconductor device 2 includes a gate voltage input terminal 4a and a terminal 6a that outputs a temperature dependent voltage.

The controller 10 includes a driver 12 and a temperature voltage output circuit 14. The temperature voltage output circuit 14 includes a PWM gate voltage detection unit 16, a triangular wave generation unit 18, a constant current circuit 20, and a comparator 22.

A microcomputer (not shown) is provided in front of the low-voltage wirings 24c and 24d. The microcomputer includes, for example, a central control unit (CPU). The microcomputer receives a PWM temperature voltage, which will be described later, from the temperature/voltage output circuit 14 via the low voltage side wiring 24d and a photo coupler (not shown). The microcomputer analyzes the received PWM temperature voltage and other conditions such as vehicle speed. The microcomputer sets the duty ratio for driving the switching element 4 from the analysis result. The microcomputer transmits a PWM signal having the set duty ratio to the driver 12 via a photo coupler (not shown) and the low voltage side wiring 24c. The driver 12 uses the received PWM signal to generate a PWM gate voltage. Specifically, the driver 12 generates a PWM gate voltage having the same duty ratio as the PWM signal received from the microcomputer and having a voltage that can actually turn on or off the switching element 4. The driver 12 causes the switching element 4 to perform the processing instructed by the microcomputer by applying the generated PWM gate voltage to the gate voltage input terminal a of the switching element 4.

Next, the temperature/voltage output circuit 14 will be described. The analog voltage of the temperature detection element 6 is input to the comparator 22 of the temperature voltage output circuit 14. The comparator 22 compares the analog voltage of the temperature detection element 6 with the waveform generated by the triangular wave generator 18 to generate a PWM temperature voltage with a varying duty ratio. More specifically, PWM modulation is performed in which a period in which the triangular wave exceeds the analog voltage is a pulse-on width and a period in which the triangular wave is lower than the analog voltage is a pulse-off width. The temperature voltage output circuit 14 outputs the PWM temperature voltage generated by the comparator 22 to the above-mentioned microcomputer via the low voltage side wiring 24d and a photo coupler (not shown). That is, the temperature voltage output circuit 14 outputs the PWM temperature voltage obtained by modulating the temperature dependent voltage.

The cycle of the PWM gate voltage and the PWM temperature voltage will be described. As described above, the PWM gate voltage is generated by the driver 12 using the PWM signal transmitted from the microcomputer. The microcomputer changes the cycle of the PWM signal depending on the magnitude of the change per unit time of the voltage output by the device switching by the semiconductor device 2. Specifically, when there is a large change in the voltage output from the device per unit time, the trackability is improved by shortening the cycle of the PWM signal. On the other hand, when the change in the voltage output from the device per unit time is small, the cycle of the PWM signal is lengthened to reduce noise due to switching. As described above, the driver 12 uses the PWM signal to generate the PWM gate voltage. Therefore, when the cycle of the PWM signal changes, the cycle of the PWM gate voltage generated by the driver 12 also changes.

Here, the influence of the PWM gate voltage on the PWM temperature voltage will be described once the cycle of the PWM gate voltage and the PWM temperature voltage is the same with reference to FIGS. 2 and 3. FIG. 2A shows a pulse wave Pg of the PWM gate voltage. As shown in FIG. 2A, the pulse wave Pg has a period Tg. The pulse wave Pg has a pulse-on width tg1 and a pulse-off width tg2. In FIG. 2, the pulse wave Pg is enlarged and expressed, but the actual cycle Tg is very short, for example, about 0.07 ms.

FIG. 2B shows the analog voltage Vt of the temperature detection element 6. Although the analog voltage Vt changes depending on the temperature of the temperature detection element 6, as described above, the analog voltage Vt is represented by a constant value because it is a very short time in FIG. As shown in FIG. 2B, noises are overlapped when the pulse wave Pg of the PWM gate voltage is turned on and turned off. Each noise is a triangular wave having the maximum voltage at the turn-on and turn-off timings of the pulse wave Pg shown in FIG. The noise drops from the maximum voltage and returns to the value of the analog voltage Vt, and thereafter, a triangular wave that is vertically symmetrical about the analog voltage Vt is generated and disappears. Note that the noises shown in FIGS. 2C and 2F are similar noises n1 to n6, but the reference numerals are omitted for the sake of clarity.

The effect of the above-mentioned noise on the PWM temperature voltage when PWM-modulating the analog voltage Vt of FIG. 2B will be described with reference to FIG. FIG. 3 is an enlarged view showing a range III in FIG. In FIG. 3C, the triangular wave wt is overlapped on the analog voltage Vt of FIG. 2B and the noise overlapped. In FIG. 3C, the voltage v1 when the noise n1 does not overlap the analog voltage Vt in the period from the rise of the noise n1 to the disappearance thereof is shown by a two-dot chain line. The voltage v1 is a straight line connecting the end point on the left side of the drawing, which is the starting point of the noise n1, and the end point on the right side of the drawing, which is the ending point of the noise n1. The voltage v1 is the same voltage as the analog voltage Vt because it is not affected by the noise n1. In FIG. 3C, similarly, in the period from the rise of the noise n2 to the disappearance, the voltage v2 when the noises n2 do not overlap, and the noise n3 in the period from the rise to the disappearance of the noise n3. The voltage v3 when there is no overlap is shown by a two-dot chain line. Like the voltage v1, the voltage v2 and the voltage v3 are the same voltage as the analog voltage Vt.

As shown in FIG. 3C, the triangular wave wt is composed of a straight line extending upward from the left side of the drawing and a straight line extending downward to the right. As shown in FIG. 2C, the triangular wave wt repeats rising and falling to the right at a constant cycle Tt. As shown in FIG. 3C, the triangular wave wt intersects the voltage v1 described above at the intersection point p1. Subsequently, the triangular wave wt intersects the noise n1 at the intersection point p2. The triangular wave wt further rises to the right, reaches the highest point, and then falls to the right. The triangular wave wt, which has dropped to the right, intersects the analog voltage Vt at the intersection point p3. After that, the triangular wave wt reaches the lowest point and rises to the right. The triangular wave wt rising to the right intersects with the voltage v3 at the intersection point p4, similarly to the intersection point p1. Further, the triangular wave wt intersects the noise n3 at the intersection point p5. As shown in FIG. 2C, the triangular wave wt subsequently intersects with the analog voltage Vt and each noise at the same cycle Tt.

In FIG. 3C, the triangular wave wt intersects the voltage v1 at the timing t1. The triangular wave wt intersects the noise n1 at the timing t2. The triangular wave wt intersects the analog voltage Vt at the timing t3. The triangular wave wt intersects the voltage v3 at the timing t4. The triangular wave wt intersects the noise n3 at the timing t5. Hereinafter, with reference to FIGS. 3D and 3E, a pulse wave in which the analog voltage Vt when the noises do not overlap are PWM-modulated and a pulse wave in which the analog voltage Vt where the noises overlap are PWM-modulated The difference between the waves will be described.

First, the pulse wave Pt of the PWM temperature voltage generated from the analog voltage Vt when noise does not overlap the analog voltage Vt will be described with reference to FIG. As shown in FIG. 3C, the triangular wave wt exceeds the voltage v1 at the timing t1. That is, as shown in FIG. 3D, the pulse wave Pt turns on at the timing t1. The triangular wave wt crosses the analog voltage Vt at the timing t3 and falls below the analog voltage Vt. Therefore, the pulse wave Pt turns off at the timing t3. Similarly, since the triangular wave wt exceeds the voltage v3 at the timing t4, the pulse wave Pt is turned on again at the timing t4, and the turn-on and the turn-off are repeated at the same cycle Tt as the triangular wave wt. The pulse wave Pt has a pulse-on width of tt1 and a pulse-off width of tt2.

Subsequently, the pulse wave P't of the PWM temperature voltage generated from the analog voltage Vt when the noise overlaps the analog voltage Vt will be described with reference to FIG. As shown in FIG. 3C, the triangular wave wt exceeds the noise n1 at the timing t2. That is, as shown in FIG. 3E, the pulse wave P′t turns on at the timing t2. The triangular wave wt crosses the analog voltage Vt at the timing t3 and falls below the analog voltage Vt. Therefore, the pulse wave P't is turned off at the timing t3. Since the triangular wave wt exceeds the noise n3 at the timing t5, the pulse wave P't is turned on again at the timing t5, and the turn-on and the turn-off are repeated at the cycle T't. The pulse wave P′t has a pulse-on width of t′t1 and a pulse-off width of t′t2.

The pulse wave Pt and the pulse wave P't are compared. As shown in FIG. 3D, the cycle Tt of the pulse wave Pt is the period from the timing t1 to the timing t4. Further, as shown in FIG. 3E, the cycle T′t of the pulse wave P′t is a period from the timing t2 to the timing t5. The period Tt of the pulse wave Pt and the period T't of the pulse wave P't are different at the timing of turning on at the timings t1 and t2, and at the timing of turning on again at the timings t4 and t5. Here, the difference between the timing t1 and the timing t2 and the difference between the timing t4 and the timing t5 are the turn-on timing of the pulse wave Pg (see FIG. 2A), the noise generated at the turn-on timing, and the triangular wave wt. Is the difference in the timing of intersection. The straight lines rising to the right of the triangular wave wt all have the same slope. Further, since the respective noises that overlap at the turn-on timing of the pulse wave Pg of the PWM gate voltage have the same waveform, the difference between the timings t1 and t2 is equal to the difference between the timings t4 and t5. Therefore, the cycle Tt and the cycle T't are equal.

Then, the pulse-on width and the pulse-off width of the pulse waves Pt and P't are compared. As described above, the pulse wave Pt has a pulse-on width of tt1 and a pulse-off width of tt2. The pulse wave P′t has a pulse-on width of t′t1 and a pulse-off width of t′t2. As shown in FIG. 3D, the pulse-on width tt1 of the pulse wave Pt is the period from the timing t1 to the timing t3. The pulse-off width tt2 of the pulse wave Pt is from timing t3 to timing t4. On the other hand, as shown in FIG. 3E, the pulse-on width t′t1 of the pulse wave P′t is the period from the timing t2 to the timing t3. The pulse off width t′t2 of the pulse wave P′t is the period from the timing t3 to the timing t5. That is, the pulse-on width tt1 of the pulse wave Pt is longer than the pulse-off width tt2 of the pulse wave Pt. The pulse off width tt2 of the pulse wave Pt is shorter than the pulse off width t't2 of the pulse wave P't. In other words, the duty ratio obtained by the pulse on width and the off width of the pulse wave Pt is larger than the duty ratio obtained by the pulse on width and the off width of the pulse wave P't in which noise overlaps. That is, due to the noise overlapping the analog voltage Vt, a difference occurs in the duty ratio. In other words, due to the noise overlapping the analog voltage Vt, the duty ratio of the PWM-modulated pulse wave is no longer proportional to the analog voltage Vt that changes depending on the temperature of the semiconductor device 2.

As described above, the noise overlapping the analog voltage Vt is generated at the turn-on and turn-off timings of the PWM gate voltage. As shown in FIG. 2A, the PWM gate voltage has a cycle Tg. That is, noise is generated in each cycle Tg. Here, as shown in FIGS. 2A and 2C, the timing at which the PWM gate voltage is turned on is the timing t1, and the timing at which it is turned on again is the timing t4. That is, the cycle Tg is between the timing t1 and the timing t4. As described above, the period Tt of the pulse wave Pt is also the period from the timing t1 to the timing t4. Further, the cycle Tt and the cycle T't are equal. That is, the cycle Tg and the cycle T't are equal. In other words, the PWM gate voltage and the PWM temperature voltage have the same cycle.

As described above, when the cycle Tg of the PWM gate voltage and the cycle Tt of the PWM temperature voltage are the same, the turn-on timing of the PWM gate voltage matches the turn-on timing of the PWM temperature voltage. As a result, noise generated at the turn-on timing of the PWM gate voltage affects the turn-on timing of the PWM temperature voltage. Hereinafter, the control executed in the controller 10 of the embodiment to make it difficult for the turn-on timing of the PWM gate voltage to coincide with the turn-on timing of the PWM temperature voltage will be described.

Returning to FIG. 1, the temperature voltage output circuit 14 will be described again. As described above, the temperature voltage output circuit 14 has the PWM gate voltage detection unit 16. The PWM gate voltage detection unit 16 acquires the PWM gate voltage from the driver 12. As described above, the period of the PWM signal that generates the PWM gate voltage changes. When the cycle of the PWM signal changes, the cycle of the PWM gate voltage also changes. The PWM gate voltage detection unit 16 specifies the period Tg (see FIG. 2A) of the PWM gate voltage from the acquired PWM gate voltage and transmits it to the triangular wave generation unit 18. The triangular wave generator 18 uses the received cycle Tg to generate a triangular wave having a cycle such that the ratio with the cycle Tg is a non-integer. Specifically, the triangular wave generation unit 18 sets a cycle Td (see FIG. 2F) obtained by multiplying the cycle Tg by, for example, a non-integer 8/7. The triangular wave generation unit 18 compares the triangular wave having the set period Td with the analog voltage of the temperature detection element 6, and sets the period in which the triangular wave exceeds the analog voltage as the pulse-on width, and the period in which the triangular wave is lower than the analog voltage. Is used as the pulse-off width. A pulse wave having a period Td is generated from a triangular wave having a period Td. The temperature voltage output circuit 14 uses the comparator 22 to generate a PWM temperature voltage pulse wave Pd (see FIG. 2(g)) having a period Td (see FIG. 2(g)) such that the ratio to the period Tg is a non-integer. ) Is generated. The non-integer value by which the cycle of the PWM gate voltage is multiplied is not limited to 8/7, and the triangular wave generation unit 18 sets a cycle obtained by multiplying by a different non-integer according to the cycle Tg of the PWM gate voltage.

The PWM temperature voltage having a cycle in which the ratio with the cycle Tg is a non-integer will be described with reference to FIG. FIG. 4 is an enlarged view showing a range of IV in FIG. The analog voltage Vt and noise in FIG. 4(f) are the same as those in FIG. 3(c). The triangular wave wd that generates the pulse wave has a different period from the triangular wave wt in FIG. 3C, but for ease of comparison, the timing at which the triangular wave wd and the voltage v1 intersect is set to the same timing t1 as the triangular wave wt. As shown in FIG. 4F, the triangular wave wd is composed of a straight line extending from the left side of the drawing to the right and a straight line extending to the right like the triangular wave wt. As shown in FIG. 2F, the triangular wave wd repeats rising and falling to the right at a constant cycle Td. As shown in FIG. 4F, the triangular wave wd first intersects with the voltage v1 at the intersection point p6. Subsequently, the triangular wave wd intersects with the noise n1 at the intersection point p7. After that, the triangular wave wd goes up to the right, reaches the highest point, and goes down to the right. The triangular wave wt, which has dropped to the right, intersects with the analog voltage Vt at the intersection p8. After that, the triangular wave wd reaches the lowest point and rises to the right. The rising triangular wave wd intersects the analog voltage Vt at the intersection p9. As described above, the triangular wave wd repeats the intersection with the analog voltage Vt at a constant cycle Td thereafter, but as shown in FIG. 2F, the triangular wave wd crosses noise except the intersection p7. Instead, it crosses the analog voltage Vt.

In FIG. 4F, the triangular wave wd crosses the voltage v1 at the timing t6. As described above, the timing t6 is the same as the timing t1. The triangular wave wd intersects with the noise n1 at the timing t7. The triangular wave wt intersects the analog voltage Vt at the timing t8. The triangular wave wt intersects the analog voltage Vt at the timing t9.

As shown in FIG. 4F, the triangular wave wd and the noise n1 intersect at timing t7. The triangular wave wd exceeds the noise n1 overlapping the analog voltage Vt at the timing t7. That is, as shown in FIG. 4(g), the pulse wave Pd is turned on at the timing t7. The triangular wave wd crosses the analog voltage Vt at the timing t8 and falls below the analog voltage Vt. Therefore, the pulse wave Pd is turned off at the timing t8. Similarly, the pulse wave Pd is turned on again at the timing t9. As shown in FIG. 2G, the pulse wave Pd repeats turn-on and turn-off with the period Td thereafter, but unlike the pulse wave P't described above, it does not intersect with noise. That is, the pulse-on width td1 and the pulse-off width td2 of the pulse wave Pd after the timing t9 are determined at the timing at which the triangular wave wd and the analog voltage Vt intersect. In other words, the duty ratio of the pulse wave Pd after the timing t9 is proportional to the analog voltage Vt that changes depending on the temperature of the semiconductor device 2 without being affected by noise.

As described above, in the controller 10 of the embodiment, the ratio between the cycle Tg of the PWM gate voltage and the cycle Td of the PWM temperature voltage is set to a non-integer. Therefore, it is difficult to match the turn-on timing and/or turn-off timing of the PWM gate voltage with the turn-on timing and/or turn-off timing of the PWM temperature voltage. As a result, it is possible to prevent noise generated when the PWM gate voltage is turned on and/or turned off from affecting the PWM temperature voltage when it is turned on and/or turned off.

The points to be noted in the embodiment will be described below. In the controller 10 of the embodiment, after the PWM gate voltage detection unit 16 detects the PWM gate voltage, the triangular wave wd is generated and the ratio to the cycle is a non-integer. The technology disclosed in this specification is not limited to this. For example, when the cycle of the PWM gate voltage does not change and the cycle of the PWM temperature voltage is also fixed, the ratio of the cycles may be set to a non-integer in the initial setting. Further, in the embodiment, the case where the cycle T't of the PWM temperature voltage and the cycle Tg of the PWM gate voltage are the same is described. Even when the cycle of the PWM temperature voltage has a multiplication relationship with the cycle Tg of the PWM voltage, the turn-on and/or turn-off timing of the PWM gate voltage periodically matches the turn-on and/or turn-off timing of the PWM temperature voltage. .. Even in such a case, according to the technique disclosed in the present specification, the timing of turning on and/or turning off the PWM gate voltage is cycled to the timing of turning on and/or off of the PWM temperature voltage as described above. It is possible to prevent the physical matching.

Further, the triangular wave generation unit 18 of the embodiment performs PWM modulation in which a period in which the triangular wave exceeds the analog voltage is a pulse-on width and a period in which the triangular wave is lower than the analog voltage is a pulse-off width. Is not limited to this. On/off may be inverted, and PWM modulation may be performed in which the period in which the triangular wave exceeds the analog voltage is the pulse-off width and the period in which the triangular wave is below the analog voltage is the pulse-on width.

Furthermore, the types and specific structures of the switching element 4 and the temperature detection element 6 are not particularly limited. For example, the switching element 4 is not limited to the IGBT, and a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), an RC (Reverse C on ducting)-IGBT, or the like can be used. Further, a freewheel diode may be connected to each switching element 4 in antiparallel. Further, the temperature detecting element 6 is not limited to the diode, and another temperature detecting element such as a thermistor may be adopted.

Specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in the present specification or the drawings exert technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Further, the technique illustrated in the present specification or the drawings can simultaneously achieve a plurality of objects, and achieving the one object among them has technical utility.

1: Electric device 2: Semiconductor device 4: Switching element 4a: Gate voltage input terminal 4g: Gate electrode 6: Temperature detection element 6a: Terminal 8a: High voltage side terminal 8b: Low voltage side terminal 10: Controller 12: Driver 14: Temperature voltage Output circuit 16: PWM gate voltage detection unit 18: Triangular wave generation unit 20: Constant current circuit 22: Comparator 24c, 24d: Low voltage side wiring

Claims (1)

A controller used by connecting to a semiconductor device having a gate voltage input terminal and a temperature-dependent voltage output terminal,
A PWM gate voltage output circuit for outputting a PWM gate voltage applied to the gate voltage input terminal;
A PWM temperature voltage output circuit for outputting a PWM temperature voltage obtained by modulating the temperature dependent voltage is provided,
A controller in which the ratio of the cycle of the PWM gate voltage and the cycle of the PWM temperature voltage is set to a non-integer.

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