JPS5840433Y2 - Photocurrent amplifier circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scanning drive circuit and a root current amplification circuit for a large number of small current output type photoelectric conversion element arrays.

Conventionally, as a charge current amplification circuit for this type of photoelectric conversion unit element, a photoelectric conversion element 1 is connected to the base side of a transistor 2 as shown in FIG. There was an amplifier circuit that obtained collector currents spaced by .

The present invention uses a combination of these unit photocurrent spaced circuits to scan and drive lead lines of photoelectric conversion elements arranged in a matrix.The purpose of this invention is to reduce the circuit scale due to matrixing, and further Its purpose is to amplify and output a minute current.

FIG. 2 is a connection example when a large number of photoelectric conversion elements are connected in a matrix, and the terminal row on one side is divided into m blocks of n terminals each starting from the leftmost element (this will be referred to as the n-side). On the other side, every n terminal rows are connected to form n blocks (this will be referred to as the Y side).

Figure 3 shows the matrix components between X.
4 is the resistance of each NPN transistor, Rij (isj) photoelectric conversion element, R1sR2 is the amplifier circuit load resistance, R3
sR4 is switching Tr3.

The base input resistance of Tr4, R5-R7, is a bias resistance to complete the switching operation.

xi, y, /I′i matrix selection signal input terminal;
P//i is the amplification output terminal.

Next, to operate this, set Xi to a logic low, Y.

is a logical high.

At this time, Tr3 and Tr4 are turned on, and the emitter of the transistor Tr1 is connected to 10 Vcc, and the emitter of the transistor Tr2 is connected to GND, so that the base current jB of the transistor Tr1 becomes (]IJ). Flows from the resistor Rij of the photoelectric conversion element to the base of the transistor Tr2, and the transistor Tr1
The collector current becomes )1feiB, and an amplified output voltage R1hfe1B is obtained at the P terminal.

When x,, y, are at other than the above logic level, the inflow end or outflow end of the current to the resistor Rij of the photoelectric conversion element (j, j) is opened, so that the resistance of the photoelectric conversion element (itj) No current flows through R, , and point P becomes 11, which is the GND potential.

The above is the operation when there is optical input, but when there is no optical input, the resistance Rij of the photoelectric conversion element of (j, j) becomes ω, so it becomes jB−+O, and the potential at point P also becomes the GND level.

Therefore, use optical input! If 1ljB is modulated, the potential at point P will also be modulated and amplified according to IB.

There is also a method of providing the output terminal at the collector of transistor T r 2, but since a DC component is superimposed on the output,
= Generally difficult to use.

Figure 4 shows the connections for configuring the unit circuits in Figure 3 into the matrix shown in Figure 2. connected to each lead line connected to the amplification transistor T.
The m collectors of r1 are shared, the resistor R1 is shared, and the point P is used as an output terminal.

As explained above, according to the present invention, multiple microcurrent output type photoelectric conversion elements can be arranged into a matrix and scan-driven, and charge current amplification can also be performed, thereby reducing the circuit scale of the scanning circuit. This method has the advantage that it is not necessary to newly provide a charging current amplification circuit.

[Brief explanation of the drawing]

1A and 1B show a conventional example, and FIGS. 2 to 4 show examples of the photocurrent wiring circuit of the present invention. R□・R7...Resistor, Ri,...(itj) photoelectric conversion element resistance, Tr1 to Tr4...Transistor, X4 pY3...Matrix selection signal input terminal.

Claims (1)

[Scope of utility model registration request] When sequentially scanning a solid-state photoelectric conversion device in which a large number of photoelectric conversion elements such as silicon photodiodes and CDS photoconductors are arranged in an array, two of each photoelectric conversion unit element are scanned.
One of the lead wires of the book is connected to m blocks every n from the end, and the other is connected every n to n blocks to form an mXn matrix, and each m block is connected to m blocks of amplifying PNP transistors. the n blocks are each connected to n NPN) transistors, and each P
Connect the PNP) transistor for matrix selection between the emitter of the NP) transistor and the power supply, and connect the NPN for matrix selection between the terminal and GND of each NPN) transistor.
) to connect the transistors, and each amplification P
NP) A photocurrent amplifier circuit characterized in that the collectors of transistors are shared and connected to GND through a single load resistor, and the collector side of this resistor is used as an output terminal.