JPH06268504A - Semiconductor device drive circuit - Google Patents

Abstract

PURPOSE:To provide a semiconductor device drive circuit provided with a function for monitoring an effect of a radiant ray onto a semiconductor device and for recovering an electric characteristic deteriorated by the effect of the radiant ray. CONSTITUTION:The drive circuit is provided with a semiconductor device 12 whose source connects to a drive power supply 14 via a resistor 13 and whose gate and drain connect to ground, a differential amplifier 15 generating a detection voltage in response to a voltage between both terminals of the resistor 13, a reference voltage source 16 generating a reference voltage, an error amplifier 17 outputting an error voltage based on the detected voltage and the reference voltage, light sources 25, 26 arranged opposite respectively to the semiconductor device 12 and the electric circuit 11, switches 19, 20 connected between the light sources and power supplies 22, 23 for the light sources and turned on/off in response to the error voltage and a switch 21 connected between the electric circuit 11 and a drive power supply 24 and turned off/on in response to the error voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device drive circuit, and more particularly to a radiation resistant semiconductor device drive circuit for driving a semiconductor device while monitoring the radiation dose.

[0002]

2. Description of the Related Art A conventional semiconductor device drive circuit simply supplies a drive voltage to a semiconductor device.

[0003]

Generally, when a semiconductor device is used in a radiation environment, its electrical characteristics deteriorate. For example, in a MOS field effect transistor, an oxide film of a gate electrode portion having a composition of silicon dioxide is exposed to radiation, and electrons in the valence band are excited by a conductor due to an ionizing action generated by the exposure, so that a valence band is generated. Holes are trapped. As a result, the electrical characteristics such as a permanent drift phenomenon of the threshold value are deteriorated and the function as an electric circuit is lost. Also,
Even in a semiconductor device having a structure in which MOS type field effect transistors and bipolar transistors are monolithically integrated, a similar phenomenon occurs in a separation band having a composition of silicon dioxide, which electrically separates these transistors, and the same phenomenon occurs between the transistors. The isolation function is impaired, and leakage current or more current flows and destroys the transistor.

The conventional drive circuit has a problem that it is impossible to eliminate the influence of these radiations.

An object of the present invention is to provide a semiconductor device drive circuit having a function of monitoring the influence of radiation and recovering the electrical characteristics deteriorated by the influence of radiation.

[0006]

According to the present invention, there is provided a semiconductor device drive circuit having a first drive power source for driving a first semiconductor device, the second semiconductor device monitoring a radiation dose. A resistor connected between a second driving power source for driving the second semiconductor device, a differential amplifier for generating a detection voltage according to a potential difference between both terminals of the resistor, and a reference voltage Reference voltage source, an error amplifier that outputs an error voltage based on the difference between the detected voltage and the reference voltage, and first and second light sources that are arranged to face the first and second semiconductor devices, respectively. When,
First and second switches that are respectively connected between the first and second light sources and the first and second light source power supplies that drive the light sources, and that are turned on / off in accordance with the potential of the error voltage. And a third switch connected between the first radiation-resistant semiconductor device and the first drive power supply and turned on / off according to the potential of the error voltage. The circuit is obtained.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention. The semiconductor device drive circuit of this embodiment is a drive circuit for driving an electric circuit 11 including a semiconductor device (not shown). This semiconductor device drive circuit has a semiconductor device (MOS type field effect transistor) 12 for monitoring radiation. The source of the semiconductor device 12 includes a resistor 13
The driving power supply 14 is connected via the, and the gate and drain are grounded. An optical waveguide is formed on the gate. The semiconductor device drive circuit also includes an amplifier 15 that outputs a voltage according to the potential difference across the resistor 13, a reference voltage source 16 that generates a reference voltage, and a potential difference between the outputs of the amplifier 15 and the reference voltage source 16. Error amplifier 17 for generating a voltage, relays 18 and relay switches 19, 20, and 21, power sources 22 and 23 for light sources connected to these relay switches 19 and 20, respectively, and electric power connected to relay switch 21. It has a circuit driving power supply 24 and light sources 25 and 26 arranged to face the semiconductor device 12 and the semiconductor devices in the electric circuit 11.

Next, the operation of this drive circuit will be described. In the normal state, as shown in the figure, the relay switches 19 and 20 are off, and the relay switch 21 is on. That is, the electric circuit 11 is driven. At this time,
No current flows between the source and drain of the semiconductor device 12.

When this drive circuit is exposed to radiation, the semiconductor device 12 is exposed and a dark current flows between the source and drain. That is, a potential difference is generated across the resistor 13. The amplifier 15 outputs a detection voltage based on this potential difference.
The error amplifier 17 compares the reference voltage from the reference voltage source 16 with the detection voltage from the amplifier 15, and when the detection voltage exceeds the reference voltage, the error is amplified and the relay 18 is driven.
As a result, the relay switches 19 and 20 are turned on and the relay switch 21 is turned off. Then, the light sources 25 and 26
Lights up and the electric circuit 11 is stopped. Light source 25
The holes trapped inside the semiconductor device 12 and the semiconductor device of the electric circuit 11 are detrapped and the deteriorated electrical characteristics can be restored by lighting the light emitting devices 26 and 26.

When the electric characteristics of the semiconductor device 12 are restored, the dark current stops flowing, so that the potential difference of the resistor 13 disappears and the output of the error amplifier 17 also disappears. As a result, the relay switches 19 and 20 are turned off and the relay switches are turned on to return to the original state. That is, in the present embodiment, it is considered that when the electrical characteristics of the semiconductor device 12 are restored, the electrical characteristics of the semiconductor device of the electric circuit 11 are also restored.

[0011]

According to the present invention, the exposure situation is monitored by using a monitor semiconductor device different from the semiconductor device to be driven, and the light source is turned on when the monitor semiconductor device is deteriorated in electrical characteristics due to the exposure. By stopping the driving of the semiconductor device to be driven by irradiating the semiconductor device with light, it is possible to recover the influence of the exposure of the driven semiconductor device and avoid destruction.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

[Explanation of symbols]

 11 Electric Circuit 12 Semiconductor Device 13 Resistance 14 Driving Power Supply 15 Amplifier 16 Reference Voltage Source 17 Error Amplifier 18 Relay 19, 20, 21 Relay Switch 22, 23 Light Source Power Supply 24 Electric Circuit Driving Power Supply 25, 26 Light Source

Claims (1)

[Claims] 1. A semiconductor device drive circuit having a first drive power supply for driving a first semiconductor device, the second semiconductor device monitoring a radiation dose, and the second semiconductor device.
A resistor connected between the second driving power source for driving the semiconductor device, a differential amplifier for generating a detection voltage according to a potential difference between both terminals of the resistor, and a reference voltage for generating a reference voltage. A source, an error amplifier that outputs an error voltage based on a difference between the detected voltage and the reference voltage, and a first amplifier arranged to face the first and second semiconductor devices, respectively.
And a second light source, respectively connected between the first and second light sources and first and second light source power sources for driving the light sources, and turned on / off in accordance with the potential of the error voltage. Having first and second switches, and a third switch which is connected between the first radiation resistant semiconductor device and the first driving power supply and which is turned on / off according to the potential of the error voltage. A semiconductor device drive circuit characterized by: