JP4024531B2 - Thermistor built-in power semiconductor module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an increase in switching loss even when the temperature of a semiconductor chip rises, though the conventional semiconductor module for electric power comprising an inverter, where a plurality of semiconductor chips for electric power such as IGBTs or FETs are fixed to a copper circuit, has such a demerit that the temperature of the semiconductor chip increases as conductive current increases and switching loss is made large, and furthermore the temperature increases as a result. <P>SOLUTION: A thermistor is arranged near a semiconductor chip for electric power on a copper circuit, and it is electrically connected with a gate, so that the resistance value of the gate is reduced when the temperature increases. In such a circuit, switching loss can be reduced because the resistance value of the gate is made small even when the temperature increases. <P>COPYRIGHT: (C)2003,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power semiconductor module incorporating a thermistor.
[0002]
[Prior art]
In a power semiconductor module in which a plurality of IGBT or FET power semiconductor chips are fixed to a copper circuit to form an electric circuit, for example, an inverter, and the entire surface except the bottom surface of the heat dissipating metal base and the terminal fitting is resin molded. As the current flowing increases and the temperature of the IGBT or FET increases, the switching loss increases. This loss becomes heat, and the semiconductor chip may eventually burn out. For this reason, when the current applied to the semiconductor chip exceeds the limit value, a current detecting means for detecting this and a current interrupting means for stopping the current are required. When the temperature of the usage environment was high, there was a situation where the current suddenly stopped during use when the load current changed.
[0003]
[Problems to be solved by the invention]
As the temperature of the semiconductor chip such as IGBT or FET as described above increases, the switching loss increases. Finally, the conventional defect of burning the semiconductor chip is eliminated, and the switching loss increases as the temperature increases. It is an object of the present invention to improve to a power semiconductor module that does not become.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the relationship between the semiconductor chip junction temperature and the switching loss was investigated. On the other hand, the relationship between the gate resistance value of the IGBT or FET and the switching loss was investigated, and the characteristic that the switching loss becomes smaller as the gate resistance value decreases was found. A copper circuit is formed on the upper surface of the metal base via an insulating layer, and two sets of power semiconductor chips of two IGBTs or FETs connected in series are connected in parallel on the copper circuit to form an electric circuit such as an inverter. In the power semiconductor module, a thermistor having a resistance value that decreases as the temperature rises in series is connected to each gate of a plurality of IGBTs or FETs that are elements constituting an electric circuit, and the thermistors are IGBTs or FETs. It was arranged on a copper circuit at a position close to the power semiconductor chip so as to have a temperature substantially equal to that of the power semiconductor chip . The thermistor is connected in series to the gate of the semiconductor chip, is connected to the control terminal fitting, and is led out to the outside. A power terminal fitting for connecting the power of the semiconductor chip to the outside is provided, and is filled with a filler that covers the copper circuit, the semiconductor chip and the thermistor, and the power terminal fitting and the portion excluding the tip of the control terminal fitting, A power semiconductor module is formed by exposing the lower surface of the metal base.
[0005]
A thermistor is disposed in the vicinity of the semiconductor chip, the thermistor is connected in series to the gate of the semiconductor chip, and a resistor is connected in series to the thermistor. It is also effective to connect and connect to a control terminal.
[0006]
When a thermistor is connected in series to the gate of the IGBT or FET, the resistance value decreases as the temperature increases, and the gate resistance value of the total combined resistance decreases as the temperature increases. Act on. Therefore, when the gate resistance is small as described above, the switching loss is small, so that the switching loss decreases as the temperature increases.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment according to the present invention will be described with reference to FIGS. In FIG. 2, reference numerals 5, 6, 7 and 8 denote IGBT or FET power semiconductor elements. The power semiconductor elements 5 and 6 are connected in series, and the power semiconductor elements 7 and 8 are connected in series. . The series circuit of the power semiconductor elements is connected in parallel to form an electric circuit having the function of an inverter. A thermistor 9 is connected in series to the gate of each power semiconductor element 5, 6, 7, 8, a resistor 10 is connected in series with the thermistor 9, and in parallel with a series circuit of the thermistor 9 and resistor 10. The resistor 11 is connected to the power semiconductor element so that the switching loss of the power semiconductor element does not increase.
[0008]
FIG. 1 is a structural diagram of a power semiconductor module when an electric circuit having an inverter function is configured. Chip components such as power semiconductor chips 5, 6, 7, 8, thermistor 9, resistors 10, 11 are fixed to a circuit board on which a copper circuit 3 is formed on the surface of the metal base 1 via an insulating layer 2. The semiconductor chips are electrically connected by a metal piece 12 or by a copper circuit 3. The thermistor 9 is disposed on the copper circuit 3 at a position close to the semiconductor chip, and is fixed so as to be substantially equal to the semiconductor chip temperature. The gate of the semiconductor chip is electrically connected by a bonding wire 15 and is connected to a control terminal fitting 13 via a resistor 10 and led out. It is also effective when the resistor 10 is omitted and it is directly connected to the control terminal fitting 13, and it is also effective that the resistor 11 is connected between the gate and the control terminal fitting 13. A power semiconductor module is formed by covering the entire component mounting side of the metal base 1 with a filler (not shown). The filler is a filling insulator such as an epoxy resin.
[0009]
The power semiconductor chips 5, 6, 7, and 8 are fixed to the copper circuit 3 and led out to the outside by power terminal fittings 14 connected to the copper circuit. The resistor 10 connected in series to the thermistor 9 connected between the control terminal fitting 13 and the gate of the power semiconductor chip 5, 6, 7, 8 may have a zero resistance value, that is, the resistance required for the thermistor alone. When the value is obtained, neither the resistor 10 nor the resistor 11 is required, and it is also effective to form a copper circuit that is directly connected from the thermistor 9 to the control terminal fitting. Although the embodiment described above is shown only for the basic circuit, the circuit component constituting the peripheral circuit such as the circuit for rectifying the alternating current into the direct current when the semiconductor protective circuit component is incorporated and integrated. It is also included in the scope of the embodiment to be formed as a power semiconductor module having a comprehensive function.
[0010]
【The invention's effect】
According to the present invention, since the switching loss increases as the temperature of the power semiconductor chip such as IGBT or FET increases, the conventional defect that the semiconductor chip is burned out at higher temperatures can be eliminated. It can be made smaller than conventional power semiconductor modules that require detection means and current interrupting means, and the number of manufacturing steps can be reduced. In addition, it can be provided at low cost by reducing the materials, and also contributes to resource and energy savings. So industrial value is great.
[Brief description of the drawings]
FIG. 1 is a structural perspective view of a power semiconductor module with a built-in thermistor according to an embodiment of the present invention.
FIG. 2 is a circuit diagram of a thermistor built-in power semiconductor module according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal base 2 Insulation layer 3 Copper circuit 4 Circuit board 5, 6, 7, 8 Power semiconductor chip 9 Thermistor 10, 11 Resistor 12 Metal piece 13 Control terminal metal fitting 14 Power terminal metal fitting 15 Bonding wire 16 Filler

Claims (1)

A copper circuit is formed on an upper surface of a metal base via an insulating layer, and two sets of power semiconductor chips of two IGBTs or FETs connected in series on the copper circuit are connected in parallel to form an electric circuit. A power terminal fitting for connecting the electric power to the outside, filled with a filler covering the copper circuit, the power semiconductor chip and the power terminal fitting excluding the tip, and leading out the power terminal fitting and A power semiconductor module formed by exposing a lower surface includes a thermistor whose resistance value decreases as the temperature increases, and the power semiconductor chip has a temperature substantially equal to that of the power semiconductor chip. placed copper circuit position close to, be characterized by the thermistor to the gate of the semiconductor chip is derived as the respective terminal control connected in series Semiconductor module for thermistor visceral power

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