JPS60182277A - Drive circuit of charge injection device - Google Patents

Abstract

PURPOSE:To detect a line causing a fault by providing a current waveform detecting circuit in common among plural inverters and power supplies. CONSTITUTION:Inverters I1,I2-In consist of CMOSes and inputs Vinl-Vinn are received from a shift register 3. Thus, when a low level is given to the Vinl of the inverter I1, for example, a p-channel transistor (TR) Tp is turned on and an-channel TRTn is turned off, then a pulse current flow from a power supply VDD in the path of a resistor (r), the TRTp and a picture element CL1. On the other hand, in bringing the level of the input Vin3 of the inverter I3 to a low level similarly, a current flows from the VDD through the picture element CL3, but since a capacitor C and a resistor RL are connected in parallel equivalently, a DC flows through the resistor RL. Thus, in bringing the Vinl-Vinn to a low level sequentially, the voltage Vr across the resistor (r) becomes a pulse form waveform when the picture element is normal and if there is a fault, a DC component voltage is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a charge injection device (al) used as a photodetector.
Hereinafter, CID; Cha4ge Injection D
(referred to as EVICE).

(b) Conventional technology and problems To drive a CID as an optical sensor in which multiple pixels are arranged in a matrix, drive pulses generated by a shift register are applied to the drive line via a CMOS inverter as an output sofa. Ta.

However, conventional devices have the disadvantage that even if a fault occurs, it cannot be detected in which line the fault has occurred.

(C) Object of the Invention An object of the present invention is to eliminate the above-mentioned drawbacks of the conventional method and to enable detection of a faulty line.

(di) Structure of the Invention To achieve the above object, the present invention is a CID drive circuit, which includes a shift register and a plurality of complementary MOs that respectively receive a plurality of outputs of the shift register and drive a charge injection device.
It is characterized by having an S inverter and a current waveform detection means provided in common between the plurality of inverters and a power source.

(el　Embodiments of the invention An embodiment of the present invention will be described above using the drawings.

In the present invention, the CID pixels have an MO3 structure, and while normal pixels are capacitive, failures occur.

For example, if there is a leak in the insulating film between the electrode and the substrate,
Since a resistor is equivalently connected to the pixel, power only flows in the form of alternating current to a normal pixel, but direct current also flows to a faulty pixel.

FIG. 1 is a diagram showing an embodiment of the present invention, where 1 is a CID, 2 is a
is a CID drive circuit, which includes a shift register 3 and inverters 11-In. Each inverter is commonly connected to the power supply ■ through a resistor r. , is connected to.

In addition, the output of each inverter corresponds to each pixel CL1 to CIDI.
Each is connected to the CLN.

The inverter and pixels are shown in more detail in Figure 2.
Each inverter is configured with 0MO3 and receives inputs Van1 to V7sn from the shift register 3.

Therefore, for example, if the Vin of the inverter I is set to a low level,
), and when the p-channel transistor Tp is turned on and the n-channel transistor Tn is turned off, a pulse-like current flows through the path from the power supply Vl) Il+ to the resistor r and the transistor Tp1 and the pixel CLI.

On the other hand, the input Vrn3 of inverter ■3 is similarly set to “I7”.
”, a current flows from Vpo through the pixel CL3, but at this time, since the capacitor C and the resistor RL are equivalently connected in parallel, a DC-like current flows through RL.

Therefore, as shown in FIG. 3, Vin1 to vi are sequentially displayed.

When the voltage Vr across the resistor r is set to "L", only a pulse-like waveform will be detected if the @ element is normal, but if there is a failure like pixel CL 3, the voltage Vr across the resistor r will be detected at position 3 of Vr. Since the DC component Vd appears as shown, it is possible to know where the fault has occurred.

Further, the value of the resistor RL can also be determined from the value of the voltage Vd.

(fl) As described in detail, according to the present invention, it is possible to detect a location where a fault occurs in a CID pixel, and further, it is also possible to know the resistance value of a fault line.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing the embodiment of FIG. 1 in more detail, and FIG. 3 is a diagram showing waveforms at various parts. 1: CID, 2: CID drive circuit, 3: Shift register, l7-In: Inverter 1 r: Resistor. ■ρρ: Power source −−−−−−−−−−−−−” Figure 1, Figure 2 Σ

Claims (1)

[Claims] A shift register, a plurality of complementary MOS inverters each receiving a plurality of outputs of the shift register and driving a charge injection device, and a current waveform detection means provided in common between the plurality of inverters and a power supply. Characteristic drive circuit 6 of charge injection device