Electronic circuit

Abstract

To provide a technique that can adjust the difference in current rise speed when multiple transistors are turned on.SOLUTION: An electronic circuit may include a plurality of transistors connected in parallel, and a gate resistor connected in series to the gate of each transistor, the gate resistor having a resistance value that changes depending on temperature.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology disclosed in this specification relates to electronic circuits. [Background technology]

[0002] Patent Document 1 discloses a device including a FET and a gate control element connected to a gate terminal of the FET to change the voltage of the gate terminal. In the configuration of Patent Document 1, when the temperature of the FET rises to a predetermined temperature or higher, the gate control element changes the voltage of the gate terminal to control the channel current between the source and drain of the FET. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-228706 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration of Patent Document 1, a single transistor (FET) is used, but multiple transistors may be connected in parallel. In such a configuration, a difference may occur in the rise speed of current when the multiple transistors are turned on. This specification provides a technology that can adjust the difference in the rise speed of current when the multiple transistors are turned on. [Means for solving the problem]

[0005] In a first aspect of the present technology, an electronic circuit may include a plurality of transistors connected in parallel, and a gate resistor connected in series to a gate of each of the transistors, the gate resistor having a resistance value that changes depending on temperature.

[0006] According to this configuration, the resistance value of each gate resistor changes according to temperature, so that the value of the current flowing into the gate of each transistor can be changed according to temperature. This allows the resistance value between the drain and source of each transistor to be changed, and the current rise speed when each transistor is turned on to be changed. This allows the difference in the current rise speed when multiple transistors are turned on to be adjusted.

[0007] In a second aspect, the semiconductor device according to the first aspect may further include a substrate on which a plurality of the transistors and a plurality of the gate resistors are arranged, and a resistance value of each of the gate resistors may change depending on a temperature of the substrate.

[0008] With this configuration, even if the temperature differs depending on the position on the substrate, the current rise speed when each transistor is turned on can be changed, thereby adjusting the difference in the current rise speed when multiple transistors are turned on. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a circuit diagram of an electronic circuit according to an embodiment. [Diagram 2] FIG. 13 is a graph showing an example of the relationship between the temperature and the resistance value of a gate resistor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An electronic circuit of the embodiment will be described with reference to the drawings. As shown in Fig. 1, an electronic circuit 2 of the embodiment includes a plurality of transistors (a first transistor 10 and a second transistor 20 in this embodiment) and a plurality of gate resistors (a first gate resistor 30 and a second gate resistor 32 in this embodiment). The plurality of transistors (the first transistor 10 and the second transistor 20) are connected in parallel. Also, the plurality of gate resistors (the first gate resistor 30 and the second gate resistor 32) are connected in parallel.

[0011] A plurality of transistors 10, 20 and a plurality of gate resistors 30, 32 are disposed on a substrate 50. The plurality of transistors 10, 20 are disposed at positions spaced apart from each other. In addition, the plurality of gate resistors 30, 32 are disposed at positions spaced apart from each other.

[0012] The substrate 50 is, for example, a printed circuit board having insulating properties. The temperature of the substrate 50 may change depending on the situation. For example, the substrate 50 becomes hot when the plurality of transistors 10, 20 become hot, and becomes cold when the plurality of transistors 10, 20 become cold. The temperature of the substrate 50 may also change partially. For example, when the first transistor 10 becomes hot, the portion of the substrate 50 where the first transistor 10 is arranged becomes hot, and when the first transistor 10 becomes cold, the portion of the substrate 50 where the first transistor 10 is arranged becomes cold. The same applies to the portion where the second transistor 20 is arranged.

[0013] The first transistor 10 is a field effect transistor, such as a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). The first transistor 10 includes a gate 12, a source 14, and a drain 16. The first transistor 10 is a switching element used in, for example, a converter circuit or an inverter circuit. The first transistor 10 is a voltage-controlled switching element that controls the current flowing between the drain 16 and the source 14 by controlling the voltage applied to the gate 12.

[0014] A gate 12 of the first transistor 10 is connected to a gate control unit 100 via a first gate resistor 30. A drain 16 of the first transistor 10 is connected to the positive electrode (+) of a power supply 40. A source 14 of the first transistor 10 is connected to a load 60. When the first transistor 10 is turned on, a current flows through the load 60 via the first transistor 10.

[0015] The first gate resistor 30 is connected in series with the gate 12 of the first transistor 10. As shown in FIG. 2, the first gate resistor 30 is a variable resistor whose resistance value changes according to temperature. For example, the resistance value of the first gate resistor 30 changes according to the temperature of the substrate 50 on which the first gate resistor 30 is arranged. The higher the temperature, the lower the resistance value of the first gate resistor 30, and the lower the temperature, the higher the resistance value of the first gate resistor 30. The change in the resistance value of the first gate resistor 30 changes the value of the current flowing through the first gate resistor 30.

[0016] The first gate resistor 30 is disposed in close proximity to the first transistor 10. The first gate resistor 30 is disposed in a position spaced apart from the second transistor 20. The distance between the first gate resistor 30 and the first transistor 10 is shorter than the distance between the first gate resistor 30 and the second transistor 20. In addition, the distance between the first gate resistor 30 and the first transistor 10 is shorter than the distance between the first transistor 10 and the second transistor 20. Therefore, the first gate resistor 30 is easily affected by the temperature of the first transistor 10, but is less affected by the temperature of the second transistor 20.

[0017] The second transistor 20 has the same configuration as the first transistor 10. The second transistor 20 is a field effect transistor, for example, a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). The second transistor 20 includes a gate 22, a source 24, and a drain 26. The second transistor 20 is a switching element used in, for example, a converter circuit or an inverter circuit. The second transistor 20 is a voltage-controlled switching element that controls the current flowing between the drain 26 and the source 24 by controlling the voltage applied to the gate 22.

[0018] The gate 22 of the second transistor 20 is connected to the gate control unit 100 via a second gate resistor 32. The drain 26 of the second transistor 20 is connected to the positive electrode (+) of the power supply 40. The source 24 of the second transistor 20 is connected to a load 60. When the second transistor 20 is turned on, a current flows through the load 60 via the second transistor 20.

[0019] The second gate resistor 32 is connected in series with the gate 22 of the second transistor 20. As shown in FIG. 2, the second gate resistor 32 is a variable resistor whose resistance value changes according to temperature. For example, the resistance value of the second gate resistor 32 changes according to the temperature of the substrate 50 on which the second gate resistor 32 is arranged. The higher the temperature, the lower the resistance value of the second gate resistor 32, and the lower the temperature, the higher the resistance value. The change in the resistance value of the second gate resistor 32 changes the value of the current flowing through the second gate resistor 32.

[0020] The second gate resistor 32 is disposed in close proximity to the second transistor 20. The second gate resistor 32 is disposed at a distance from the first transistor 10. The distance between the second gate resistor 32 and the second transistor 20 is shorter than the distance between the second gate resistor 32 and the first transistor 10. In addition, the distance between the second gate resistor 32 and the second transistor 20 is shorter than the distance between the first transistor 10 and the second transistor 20. Therefore, the second gate resistor 32 is easily affected by the temperature of the second transistor 20, but is less affected by the temperature of the first transistor 10.

[0021] The power supply 40 of the electronic circuit 2 is, for example, a secondary battery such as a lithium ion battery, a nickel metal hydride battery, or a lead storage battery. In a modified example, the power supply 40 may be a primary battery. The power supply 40 supplies power to a load 60 via the first transistor 10 and the second transistor 20. The load 60 is, but is not limited to, for example, a resistive load, an inductive load, or a capacitive load. The positive electrode (+) of the power supply 40 is connected to the drain 16 of the first transistor 10 and the drain 26 of the second transistor 20. The power supply 40 applies a voltage between the drain 16 and the source 14 of the first transistor 10 and between the drain 26 and the source 24 of the second transistor 20. The negative electrode (-) of the power supply 40 is, for example, grounded.

[0022] The gate control unit 100 controls the operation of the first transistor 10 and the second transistor 20. The gate control unit 100 applies a gate drive voltage to the gate 12 of the first transistor 10 and the gate 22 of the second transistor 20. That is, the gate control unit 100 inputs an on signal and an off signal to the gates 12, 22 of the multiple transistors 10, 20 at a predetermined timing. The gate control unit 100 inputs an on signal and an off signal based on a predetermined duty ratio. The gate control unit 100 may input a signal to the gate 12 of the first transistor 10 and the gate 22 of the second transistor 20 at the same timing or at different timings.

[0023] In the electronic circuit 2 configured as above, when the first transistor 10 is repeatedly turned on and off, the temperature of the first transistor 10 gradually increases. When the first transistor 10 becomes hot, the first gate resistor 30 also becomes hot, and the resistance value of the first gate resistor 30 decreases. Then, the current value flowing through the first gate resistor 30 increases, and the current value flowing into the gate 12 of the first transistor 10 increases. In the first transistor 10, when the current value flowing into the gate 12 increases, the resistance value between the drain 16 and the source 14 decreases. This increases the rise speed of the current when the first transistor 10 is turned on. Also, since the resistance value between the drain 16 and the source 14 decreases, the temperature of the first transistor 10 gradually decreases.

[0024] When the first transistor 10 becomes cold, the first gate resistor 30 also becomes cold, and the resistance value of the first gate resistor 30 becomes high. This reduces the value of the current flowing through the first gate resistor 30, and the value of the current flowing into the gate 12 of the first transistor 10 becomes small. In the first transistor 10, when the value of the current flowing into the gate 12 becomes small, the resistance value between the drain 16 and the source 14 becomes high. This slows down the rise speed of the current when the first transistor 10 is turned on.

[0025] On the other hand, when the resistance value between the drain 16 and the source 14 of the first transistor 10 increases, the resistance value between the drain 26 and the source 24 of the second transistor 20 decreases relatively. As a result, the current value flowing between the drain 26 and the source 24 of the second transistor 20 increases, and the second transistor 20 becomes hot. When the second transistor 20 becomes hot, the second gate resistor 32 becomes hot, and the resistance value of the second gate resistor 32 decreases. As a result, the current value flowing through the second gate resistor 32 increases, and the current value flowing into the gate 22 of the second transistor 20 increases. In the second transistor 20, when the current value flowing into the gate 22 increases, the resistance value between the drain 26 and the source 24 decreases. As a result, the rise speed of the current when the second transistor 20 is turned on becomes faster. Also, since the resistance value between the drain 26 and the source 24 decreases, the temperature of the second transistor 20 gradually decreases.

[0026] When the second transistor 20 becomes cold, the second gate resistor 32 also becomes cold, and the resistance value of the second gate resistor 32 becomes high. This reduces the value of the current flowing through the second gate resistor 32, and the value of the current flowing into the gate 22 of the second transistor 20 becomes small. In the second transistor 20, when the value of the current flowing into the gate 22 becomes small, the resistance value between the drain 26 and the source 24 becomes high. This slows down the rise speed of the current when the second transistor 20 is turned on.

[0027] On the other hand, when the resistance value between the drain 26 and the source 24 of the second transistor 20 increases, the resistance value between the drain 16 and the source 14 of the first transistor 10 relatively decreases. As a result, the current value flowing between the drain 16 and the source 14 of the first transistor 10 increases, and the first transistor 10 becomes hot.

[0028] In the electronic circuit 2 configured as described above, the difference between the rise rates of the currents when the first transistor 10 and the second transistor 20 are turned on is adjusted by changing the rise rates of the currents.

[0029] (effect) The electronic circuit 2 of the embodiment has been described above. As is not clear from the above description, the electronic circuit 2 includes a plurality of transistors 10, 20 connected in parallel, and gate resistors 30, 32 connected in series to the gates 12, 22 of the transistors 10, 20. The resistance value of each of the gate resistors 30, 32 changes depending on the temperature.

[0030] According to this configuration, the resistance value of each gate resistor 30, 32 changes in response to temperature, so that the value of the current flowing into the gate 12, 22 of each transistor 10, 20 can be changed in response to temperature. This makes it possible to change the resistance value between the drain 16, 26 and the source 14, 24 of each transistor 10, 20, and to change the rise speed of the current when each transistor 10, 20 is turned on. This makes it possible to adjust the difference in the rise speed of the current when the multiple transistors 10, 20 are turned on.

[0031] (Modification) (1) The resistance value of the first gate resistor 30 may change depending on the temperature of the substrate 50 on which the first gate resistor 30 is arranged. For example, the resistance value of the first gate resistor 30 may be lowered when the portion on which the first gate resistor 30 is arranged becomes hot, and the resistance value of the first gate resistor 30 may be higher when the portion on which the first gate resistor 30 is arranged becomes cold.

[0032] Furthermore, the resistance value of the second gate resistor 32 may change depending on the temperature of the substrate 50 on which the second gate resistor 32 is arranged. For example, the resistance value of the second gate resistor 32 may be reduced when the temperature of the portion on which the second gate resistor 32 is arranged becomes high, and the resistance value of the second gate resistor 32 may be increased when the temperature of the portion on which the second gate resistor 32 is arranged becomes low.

[0033] With this configuration, it is possible to change the rate of rise of the current when each of the transistors 10, 20 is turned on, even if the temperature differs depending on the position on the substrate 50. This makes it possible to adjust the difference in the rate of rise of the current when the multiple transistors 10, 20 are turned on.

[0034] (2) In the above embodiment, the electronic circuit 2 has been described as having a simple configuration including the first transistor 10 and the second transistor 20, but is not limited to this configuration. For example, the electronic circuit 2 may include three or more transistors. Furthermore, the technology described in this specification may be used in electronic circuits such as converter circuits, inverter circuits, and motor circuits.

[0035] Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful. [Explanation of symbols]

[0036] 2: electronic circuit, 10: first transistor, 20: second transistor, 30: first gate resistor, 32: second gate resistor, 40: power supply, 50: substrate, 60: load, 100: gate control unit

Claims

1. A plurality of transistors connected in parallel; a gate resistor connected in series to a gate of each of the transistors, the gate resistor having a resistance value that changes depending on temperature.

2. 2. The electronic circuit of claim 1, a substrate on which a plurality of the transistors and a plurality of the gate resistors are disposed; The resistance of each of the gate resistors varies in response to a temperature of the substrate.

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