CN2697666Y

CN2697666Y - Structure for photoelectric sampling control circuit

Info

Publication number: CN2697666Y
Application number: CN 02283500
Authority: CN
Inventors: 马庆容
Original assignee: Shanghai Fudan Microelectronics Co Ltd
Current assignee: Shanghai Fudan Microelectronics Co Ltd
Priority date: 2002-12-24
Filing date: 2002-12-24
Publication date: 2005-05-04
Anticipated expiration: 2012-12-24

Abstract

The utility model relates to a structure of a photoelectric sampling control circuit. In the prior art, the circuit structure has the defects of average power-hungry of the system, short service life of the photoemissive cell, astable circuit running, etc. The utility model adds a receiving key to the photoelectric receiving tube Q2 on the base of the prior art, namely that when the photoemissive cell Q1 is closed, the state of the receiving control signal is determined by the state of the previous sampling point; when the photoemissive cell Q1 is opened, the receiving control signal is high, and Q2 is bias. The utility model reduces the average power consumption of the system as well as prolongs the service life of the photoemissive cell, and the circuit runs stably and effectively.

Description

A kind of structure of photoelectricity sampling control circuit

Technical field

The utility model relates to the circuit structure that uses photoelectrical coupler that signal specific is sampled.

Background technology

At present, photoelectric sampling circuit is widely used in the various metering circuits, mainly finishes the function that physical quantitys such as position, speed is changed into electric signal.Photoelectric sampling circuit mainly is made up of photoemission circuit and receiving circuit, the light that radiating circuit emission is used to survey, and as infrared ray, receiving circuit is according to the power of the light of receiving, produces different electric signal and finishes measurement to measurand.

Because photoemission cell generally needs bigger current drives (needing tens milliamperes electric current as infrared transmitting tube), often make the average power consumption of entire circuit be difficult to descend; Photoemission cell operates continually at the pattern of conducting simultaneously, also makes its life-span be affected; On the other hand, because photoelectric receiving tube enters state of saturation by cut-off state, generally need the long time, this makes that the slope of its output waveform is bigger, if this waveform directly exports the digital processing circuit of back level to, can cause the digital circuit false triggering, cause circuit working undesired, generally need in the digital circuit of the output of photoelectric receiving tube and back level, insert the impact damper of Schmidt's characteristic.In circuit design,, often be difficult to both and take into account because the switching speed of photoemission tube power and photoelectric receiving tube is conflicting.

Summary of the invention

The purpose of this utility model is to design a kind of simple in structure, power consumption is little, circuit working is reliable and stable photoelectricity sampling control circuit structure.

In order to solve power consumption and reliability problems in the photoelectric sampling circuit design, the utility model provides a kind of structure and control signal sequential with matching of photoelectricity sampling control circuit, when effectively reducing the average power consumption of photoemission cell, prolonging the life-span of photoemission cell, also guaranteed the reliability of receiving circuit.

The utility model mainly comprises the improvement to the photoelectric sampling circuit structure, and control signal sequential with matching.The utility model solves the used scheme of its technical matters: at the photoemission tube portion, the control power valve carries out periodic switch, and its cycle is identical with the sample frequency of receiving unit; Receiving unit is after photoemission cell is opened, through the delay of certain hour, the output of the photoelectric receiving tube of sampling again; Simultaneously under the state of power valve periodic switch, also can make Schmidt's impact damper of insertion can play the anti-interference effect of expection, the state of receiving tube when power valve is closed also controlled, when power valve was closed, the state of receiving end was by the once result of sampling decision before it.

In conjunction with prior art, details are as follows to technical solutions of the utility model:

In the sample circuit (Fig. 1) of prior art, photoemission cell Q1 is in continuous conducting state, and photoelectric receiving tube Q2 is biased, and controls the switch of Q2 by the power that receives light, and the output of Q2 drives output through Schmidt's impact damper.The subject matter of this circuit is that system's average power consumption is big, and the serviceable life of photoemission cell Q1 is shorter.

In the photoelectric sampling circuit (Fig. 2) of the belt switch function of prior art, photoemission cell Q1 is controlled by sampling control signal, and the input of this circuit and the waveform of output such as Fig. 3 show.When controlling of sampling when low, switch closure, its switching frequency is identical with the cycle of sampling; Photoelectric receiving tube Q2 is biased, and controls the switch of Q2 by the power that receives light, and the output of Q2 drives output through Schmidt's impact damper.Because the periodic switch of Q1, regardless of the state (as the coverage extent of mobile object to receiving tube) of measurand, in the process of each sampling, Q2 must experience one section process that does not have the light input, corresponding its output must uprise when Q1 turn-offs.This just makes in each sampling process, when Q1 opens, variation from high to low only can appear in the output of Q2, the one-way of this Q2 output, make the characteristic of Schmidt's impact damper of back effectively to use, its effect is just moved original upset level.The subject matter of this circuit is that the undesired signal of output terminal is more, and false triggering appears in the digital processing circuit of back level easily.

In the utility model photoelectric sampling circuit (Fig. 4), circuit has increased the control (receiving control) to the bias supply of photoelectric receiving tube Q2 on the basis of Fig. 2, when to receive control signal be high, switch closure, the input of this circuit and the waveform of output such as Fig. 5 show.Close at photoemission cell Q1 in (being that sampling control signal is high), receive the state decision of the state of control signal by previous sampled point, when opening (being that sampling control signal is low) at Q1, it is high receiving control signal, for Q2 provides biasing.Such control signal, avoided because the pulsation of the Q2 output waveform that the switch of Q1 causes, guaranteed that the waveform of Q2 output terminal conforms to waveform (dotted line among the figure) under the continuous conducting state of Q1, this can use the characteristic of Schmidt's impact damper of back normally, has improved the noiseproof feature of circuit.

The utility model can be to realize by special IC (as FM2306) to the control that power valve Q1 reaches receiving tube Q2, also can realize by mcu programming.No matter be the special IC or the implementation of single-chip microcomputer, those skilled in the art all can implement according to the utility model.

Effect of the present utility model is, by the periodic switch to photoemission cell, when not influencing sampled result, shortened the ON time of power valve, reduced system's average power consumption and prolonged life-span of power valve; Receiving unit has been realized Schmidt's impact damper still can effectively work under transmitting terminal periodic switch state of receiving end by the control to photoelectric receiving tube state when power valve is closed.

Description of drawings

Fig. 1 is the synoptic diagram of the photoelectric sampling circuit structure of prior art.

Fig. 2 is the synoptic diagram of photoelectric sampling circuit structure of the belt switch function of prior art.

Fig. 3 is the control timing oscillogram of Fig. 2 synoptic diagram.

Fig. 4 is the synoptic diagram of the utility model photoelectric sampling circuit structure.

Fig. 5 is the control timing oscillogram of Fig. 4 synoptic diagram.

Fig. 6 is the synoptic diagram of the circuit structure of the utility model embodiment.

1 is photoemission cell Q1 among the above-mentioned figure, the 2nd, and photoelectric receiving tube Q2, the 3rd, Schmidt's impact damper, the 4th, controlling of sampling, the 5th, photoelectric receiving tube output, the 6th, receive control, the 7th, sampling output, the 8th, special circuit or single-chip microprocessor MCU.

Embodiment

Photoelectric sampling circuit structure of the present utility model is applied to a multi-rate electric energy meter special IC, and it produces needed sampling control signal and receives control signal, finishes the sampling that mechanical electric energy meter dial plate is rotated.In Fig. 6, photoemission cell Q1 (1) is directly driven by chip (FM2306), in sampling control signal (4) conducting when low; Photoelectric receiving tube Q2 (2) is directly driven by chip (FM2306), and when to receive control signal (6) be high, Q2 (2) was biased; Be to improve noiseproof feature, the sensor input end of chip built-in Schmidt's impact damper (3).Also can pass through single-chip microcomputer (MCU) (8) or other logical circuit in addition, produce the signal (7) of this photoelectric sampling circuit of the present utility model.

Claims

1, a kind of structure of photoelectricity sampling control circuit, form by photoemission cell, photoelectricity sampling pipe, controlling of sampling, Schmidt's impact damper etc., it is characterized in that in the photoelectric sampling circuit of the belt switch function of prior art, increased the reception gauge tap (6) of photoelectric receiving tube Q2 (2) bias supply, the input of this receiving circuit and output are that photoemission cell Q1 (1) closes, and the state that receives control signal is the state of previous sampled point and deciding; Photoemission cell Q1 opens, and it is high receiving control signal, the Q2 biasing.

2, the structure of photoelectricity sampling control circuit according to claim 1 is characterized in that the acceptance control of Q2 bias supply is special IC.

3, the structure of photoelectricity sampling control circuit according to claim 1 is characterized in that the reception control of Q2 bias supply is single-chip microcomputer.