JPH01183215A - Dynamic driving circuit of photosensor - Google Patents

Abstract

PURPOSE:To set a single comparator in respective blocks and to simplify a wire harness by switching the threshold levels of the comparators and setting the threshold levels corresponding to the output levels of photosensors. CONSTITUTION:The constitution of a block B7 is set to one block, and blocks B0-B7 are provided, whereby the photosensors 2a-2h consist of the matrix of 8X8. The outputs of the photosensors 2a-2h are wired OR-connected and inputted to the - input terminal of the comparator 3 and an analogue switch 7 is changed over by scan signals A-C. The threshold levels of variable resistors 6a-6h are switched and the signals are supplied to the + input terminal of the comparator 3. Thus, the threshold levels corresponding to the output levels of the photosensors can be set and a single comparator is provided in respective blocks, whereby the simplification of constitution and the wire harness is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a photosensor dynamic drive circuit that increases the number of photosensors and makes it possible to reduce the number of parts and simplify the wiring harness.

[Conventional technology]

FIG. 4 is a block diagram showing a conventional dynamic drive circuit of a photosensor.
As shown in FIG. 5fbl, the scan signal shown in FIG.
Decoded signal “0” from timing decoder 1 through
~ “7” is input and its output is output from comparator 3a ~ 3
A sword is connected to one input terminal of h.

Comparators 3a to 5hn convert the output levels of photosensors 2a to 2h to logic levels, and their ten input terminals are grounded via capacitor C1 and connected to the connection point between resistors R1 and R2. n, resistance R1
and R2 are connected between the power supply Vcc and ground.

43 to 4h are variable resistors that are set to load resistances VRO to VRht according to the output levels of the photosensors 2a to 2h,
Each of the comparators 6a to 3h is connected between the single power terminal and the power supply Vcc.

5a to 5hi The flip/flip to be sampled according to the output raster scan timing of comparators 3a to 3h.
It is a 70-tub circuit (hereinafter referred to as FF), the outputs of the comparators 6a to 6h are input to the D terminal, and the decoded signals "0" to "7" from the timing decoder 1 are input to the T terminal.
is input f.

The output is taken out from the Q terminal.

Next, the operation will be explained. Photo sensor 2a~2hk
Scan signals A, B and Ci shown in FIG. 5 (al) are decoded by the timing decoder 1 for dynamic driving.
7”.

The photosensors 2a to 2hi are each connected to a decoding output terminal, and are dynamically driven by decoding and foil numbers rOJ to "7". A comparator 5 is connected to the output of the dynamically driven photosensors 2a to 2h.
It is supplied to one input terminal of a-3h.

By the way, the photosensors 2a to 2hli are transmission type.

Differences due to methods such as reflective type, and differences depending on usage 1c
Eri, since the output level varies, it is possible to use resistor 4a.
~4h, as shown in Figure 5+d)
It needs to be adjusted to 7.

The output of the photosensors 2a to 2h is the comparator 3a.
-3h one input terminal to the comparator threshold level of the blade gill n1 section 5 fcl No. 51a +d+
n, comparator 5a
~3h output rcFF5a input to ~5hoD terminal n
Ru. The decoded signals "0" to "7" from the a-timing decoder 1 are input to the T terminals of the FFs 5a to 5h. Therefore, the decoded signals "0" to "7" are synchronized with the dynamic drive timing. Then, the outputs of the comparators 3a to 6h are sampled.

[The problem that the invention attempts to solve]

Since the conventional dynamic drive circuit of the photosensor is configured as described above, the same number of comparators 3a to 3h as the number of photosensors 2a to 2h are required, and sensor output connections are required for each photosensor 2a to 2h. If you try to increase the number of photosensors because it requires wires,
IIf The number of air components increases with the number of photosensors. Furthermore, there were other problems such as the wire harness becoming complicated.

This method was developed to solve the above-mentioned problems, and when the photo sensor is used as an intensifier, the number of parts can be significantly reduced compared to the conventional method 9, and the wiring harness can also be simplified. The purpose of this invention is to obtain a dynamic drive circuit for a photosensor that can perform the following steps.

[Problem 4 - Means for solving fpk] Photo sensor dynamic drive circuit i according to the present invention
, as a matrix configuration of NXM, decoding consists of a photosensor that is driven elidynamically, a comparator that converts the output of this photosensor into a logic level for each M block, and a comparator that converts the output of this photosensor into a logic level for each M block, and a signal that corresponds to the output level of the N photosensors. An analog switch is provided that synchronizes the threshold level with dynamic drive timing and applies it to the comparator.

[Effect]

The analog switch in this invention adjusts the threshold level of the comparator in synchronization with the timing of the photo sensor's timing. i ri? A j;,
- Ll to the output level of the photosensor for each block.
The threshold level is set, a comparator is used for each block of photosensors, and the wiring harness is simplified.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 1 indicates scan signals A and B.

A timing decoder that decodes C and outputs decoded signals "0" to "7", and one block of photosensors such as 23 to 2hi photo interrupters? '8, photo sensor 23~2ha decode signal "0" for each block
7 is configured to be dynamically driven, and FIG. 1 shows an example of a case where the block is configured with blocks BO to B7.
7 is shown as a representative.

In this block B7, a 3a comparator,
The outputs of the -input terminals 1c and 23 to 2h of the photosensors 23 to 2h are inputted by wired OR connections.

A1 resistor at one input terminal of comparator 3? Through the power supply V
cc is connected, and the input terminal of the comparator 6 is grounded via the capacitor CIk, and is also connected to the analog switch 7.

FF in 5a to 5hiC block B7, and the fourth
This is similar to the FF shown in 1. The output of the comparator 6 is input to each terminal of FF5a to 5h, and the T bias:
Decoded signal “0” from timing decoder 1
~ "7" is input, the output of comparator 6 is sampled in synchronization with the dynamic drive timing, and Q terminal:! 1 output.

62-6hi Photo sensor 23-2h in block B7
These are variable resistors that set a threshold level corresponding to the output level of the analog switch 7, each of which is connected between the power supply and the ground, and whose respective switchable terminals a are connected to the contacts 70 to 77 of the analog switch 7. ing.

t1 Scan signals A, B,
Is the threshold level of variable resistors 6a to 6h more convenient than CtIc? A switch is made so that the signal is supplied to the input terminal of the comparator 3.

Block B7 lecture like I-hi? 1 block,
As shown in FIG. 1, eight stages of blocks BO to B7 are provided to form an 8×8 matrix of photosensors 2a to 2bt.

FIG. 2 is a block diagram of the basic configuration consisting of block B7 in FIG. 1 and the timing decoder 1 that drives it, and RO to R7 in the figure are resistors.

组 [d I will explain about the work. The drive circuits of the photosensors 2a to 2h are the same as in the case of FIG. ~ “7” in Figure 5 1c
It is similar to l.

Analog switch 7rc scan I turns off the analog input in response to A, B, and C changing from "0" to "7" in binary! In other words, when the scan signal is "D", the set voltage t of the variable resistor 6a is the threshold level of the comparator 5, and when the scan signal is "1", the set voltage t of the variable resistor 6b is set as the threshold level of the comparator 5. The output voltage is supplied to the converter 6, and the voltage can be similarly switched to the set voltage of the variable resistor of each threshold level t in response to the scan signal.

An example of the voltage change at the input terminal of comparator 6 is shown in Figure 5-1.
There's a water explosion on CL. FF5a to the output of comparator 3
~5h1C, the signals are sampled by decode signals "0" to "7" in synchronization with the dynamic drive timings of n, respectively.

The above operation is explained about block B7vc,
The same process is performed for blocks BO to B6.

In addition, in the above implementation, 1 sampling 71.1 amps 7
Of course, the case where individual FFs 5a to 5h are provided as a 0-tub circuit is shown, but the programmable keyboard/display [Co., Ltd.] which is a general-purpose LSI shown in Fig.
By using the controller LSI (8279) 9, scan signals A, B, and C can be easily generated, resulting in a simpler configuration.

Cono programmable keyboard/display controller LSI (8279) is a general-purpose LSI,
The internal VC has a total of 81 × 81 = 64 FFs having the same functions as the scan signal generation circuit of 1al and 1 in Fig. 5 and the 11th FF 5a to 5i>, and the implementation of Fig. 1. Similarly to the operation in the example, the block BO is
The input signals sent from the comparators 6 of ~B7 are sampled by four people at the terminals RO~R7.

Furthermore, since the programmable keyboard/display controller LSI (8279)8i can be directly connected to the general-purpose CPU path, it can be configured more easily than the hardware.

〔Effect of the invention〕

As described above, according to the present invention, the output t of the photosensor for each block is added to the comparator as a wired OR, and the threshold level of the comparator is determined based on the dynamic drive timing of the photosensor. Since the configuration has tM stages of blocks that can be switched by analog switches, the threshold level can be set according to the output level of the photosensor, and each block has a single comparator, simplifying the configuration and wiring harness. This makes it possible to purify the structure, which in turn has the effect of being able to be constructed at a much lower cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a dynamic drive circuit for a photosensor according to an embodiment of the present invention, FIG. 2 is a block diagram showing the basic arrangement of one block out of eight blocks in the embodiment. FIG. 3 is a block diagram of another embodiment of the dynamic drive circuit for a photosensor of the present invention, FIG. 4 is a block diagram of a conventional dynamic drive circuit for a photosensor, and FIG. 5 is a block diagram of a conventional dynamic drive circuit for a photosensor and an embodiment of the present invention. 3 is a timing chart for explaining the entire operation of the dynamic drive circuit of the photosensor. 1 is a timing decoder, 2a to 2hn photosef"j
, 3i comparator, 5a-5h flip-flop 1q1 path, 6a-6ha variable resistor, 7 analog switch. In the drawings, the same reference numerals indicate the same parts. 8: Probramab J Reckey Ho-1-/↑ Company Spray Controller 0 Figure 6 Procedural Amendment (Voluntary) 3.67 Showa Month Date

Claims (1)

[Claims] N photosensors are provided in each of the M blocks, the outputs are wired OR, and the entire structure is an M×N matrix; and a timing decoder that decodes a scan signal to dynamically drive each of the N photosensors. and a comparator provided for each of the M blocks to convert the outputs of the N photosensors into logic levels; A variable resistor sets a threshold level according to the output level of the photosensor, and a threshold level set by a variable resistor provided for each of the M blocks is switched in synchronization with the dynamic drive timing. A dynamic drive circuit for a photosensor, comprising an analog switch that applies to the comparator of each block, and a flip-flop circuit that samples the output of the comparator of each block in synchronization with the dynamic drive timing.