JPH09260592A - Integrated circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an integrated circuit which controls a gate drive semiconductor device, wherein the integrated circuit is low in cost and capable of detecting an electric current with small temperature dependence. SOLUTION: An IGBT 1 is connected to a load 4, the auxiliary emitter terminal 3 of a current detecting sense IGNT 2 is connected to a sense resistor 6 as a current detecting resistor, an integrated circuit 5 which controls the IGBT 1 surrounded with dotted lines is equipped with a gate drive circuit 9, a current detector 8, a reference voltage circuit 7, and a sense resistor 7. The sensor resistor 6 and the reference voltage circuit 7 are formed on the same semiconductor substrate, so that a voltage difference between a voltage generated by the sensor resistor 6 and a reference voltage becomes very low in temperature dependence. An outer sensor resistor can be dispensed with, and the integrated circuit 5 can be reduced in cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated circuit for controlling a gate drive type semiconductor device.

[0002]

2. Description of the Related Art FIG. 2 shows the structure of a main part of a conventional integrated circuit. The gate drive type semiconductor element (shown here as the IGBT 1) is usually used as a switch for turning on and off a load current. If the load current abnormally increases due to a load short circuit or the like, the element or the load may be destroyed. In order to avoid this overcurrent state, normally, this load current is detected so that a negative overcurrent exceeding a specified value does not flow, and the IGBT
1 is cut off or kept below a certain current value.
As a method of detecting the load current, a sense IGBT2 is provided in the IGBT1, the auxiliary emitter terminal 3 of the sense IGBT2 is connected to a sense resistor 6 which is a current detecting resistor, and the voltage generated by the resistor 6 and the integrated circuit are connected. The presence or absence of overcurrent is determined by comparing with the voltage of the reference voltage circuit 7 within 5. In this case, the sense resistor 9 and the reference voltage circuit 7 having a low temperature dependency are used to detect the current having a low temperature dependency.

[0003]

However, the sense resistor 9
Is composed of a chip resistor and is usually mounted on a printed circuit board outside the integrated circuit. The cost is increased because the chip resistor and the printed board are prepared. Further, in order to reduce the temperature dependency, it is necessary to manufacture a chip resistor having a small temperature dependency, which increases the cost of manufacturing the chip resistor.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide an integrated circuit for controlling a gate drive type semiconductor device, which is low in cost and enables current detection with little temperature dependence. It is in.

[0005]

In order to achieve the above object, in an integrated circuit for controlling a semiconductor element, a current detecting resistor for detecting a current flowing through the semiconductor element is formed. A current detection resistor and a reference voltage circuit for current detection may be formed on a semiconductor substrate on which this integrated circuit is formed. Also, whether the temperature dependence of the reference voltage is the same as the temperature dependence of the current detection resistor, or ±
It is effective to set it within 300 ppm / ° C.

With the above-described structure, the external chip resistor is incorporated in the integrated circuit of the drive circuit (control circuit), so that the cost of the chip resistor and the printed circuit board on which the chip resistor is mounted can be reduced. Further, by forming the sense resistor and the reference voltage circuit on the same semiconductor substrate, it is possible to generate the reference voltage according to the temperature change of the resistance value, and compare the voltage generated by the sense resistor with this reference voltage. For example, current detection can be performed that is almost independent of temperature changes.

[0007]

1 shows a part of an integrated circuit and a main circuit according to an embodiment of the present invention. Here, the gate drive type semiconductor device is represented by IGBT1. The IGBT 1 is connected to, for example, an inductive load 4, has a current detection sense IGBT 2, and its auxiliary emitter terminal 3 is connected to a sense resistor 6 which is a current detection resistor. Inside the dotted line is an integrated circuit 5 for controlling the IGBT, which includes a gate drive circuit 9, a current detector 8, a reference voltage circuit 7 and a sense resistor 6. Part of the load current flows to the sense IGBT 2 and the current flows to the ground through the sense resistor 6. The voltage generated across the sense resistor 6 and the reference voltage generated by the reference voltage circuit 7 are compared by the current detector 8, and the load current flowing through the IGBT 1 is controlled by the difference. Sense resistor 6 and reference voltage circuit 7
Are formed on the same semiconductor substrate, the temperature dependency of the difference between the voltage generated at the sense resistor 6 and the reference voltage becomes extremely small. A bandgap reference voltage circuit is well known as the reference voltage circuit 7. This circuit normally aims to output a reference voltage whose temperature dependence is almost zero, but by adjusting the resistance in the circuit, it becomes approximately -200.
The temperature dependence can be freely adjusted within the range of 0 ppm / ° C to +1800 ppm / ° C. Normally, the temperature dependence of resistance used in integrated circuits is from approximately +1000 ppm / ° C to +
It is 3000 ppm / ° C., and there are usually some +1500 ppm / ° C. among several types of diffusion resistance. Therefore, the temperature dependence of the reference voltage and the sense resistor formed on the semiconductor substrate can be matched within a range of ± 300 ppm / ° C.

[0008]

According to the present invention, by incorporating the conventional external sense resistor in the integrated circuit, the external sense resistor is not required and the area for installing the sense resistor can be reduced on the printed circuit board. The cost of a circuit (including an integrated circuit) can be reduced. Further, by integrating the sense resistor and the reference voltage circuit on the same semiconductor substrate, the temperature characteristics of the sense resistor and the reference voltage can be made to coincide with each other, and the temperature dependence of current detection can be reduced. Further, by reducing the temperature dependence, it is possible to improve the manufacturing yield rate and reduce the cost of the integrated circuit.

[Brief description of drawings]

FIG. 1 is a diagram showing a part of an integrated circuit and a main circuit according to an embodiment of the present invention.

FIG. 2 is a diagram showing a part of a conventional integrated circuit.

[Explanation of symbols]

 1 IGBT 2 Sense IGBT 3 Auxiliary Emitter Terminal 4 Load 5 Integrated Circuit 6 Sense Resistor 7 Reference Voltage Circuit 8 Current Detector 9 Gate Drive Circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeyuki Ohikata No. 1-1 Tanabe Shinden, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. No. 1 inside Fuji Electric Co., Ltd.

Claims (3)

[Claims] 1. An integrated circuit for controlling a semiconductor device, comprising:
An integrated circuit, wherein a current detecting resistor for detecting a current flowing through the semiconductor element is formed. 2. The integrated circuit according to claim 1, wherein a current detection resistor and a reference voltage circuit for current detection are formed on a semiconductor substrate on which the integrated circuit is formed. 3. The integrated circuit according to claim 2, wherein the temperature dependence of the reference voltage is the same as the temperature dependence of the current detecting resistor, or within ± 300 ppm / ° C.