CN203216983U

CN203216983U - Zero-crossing detection circuit

Info

Publication number: CN203216983U
Application number: CN 201320041128
Authority: CN
Inventors: 周渊
Original assignee: Zhuhai Jingxun Electronic Technology Co ltd
Current assignee: Zhuhai Jingxun Electronic Technology Co ltd
Priority date: 2013-01-24
Filing date: 2013-01-24
Publication date: 2013-09-25
Anticipated expiration: 2023-01-24

Abstract

The utility model provides a zero-crossing detection circuit, which comprises an AC-DC conversion circuit, a power frequency signal detection circuit and an optical coupling isolation output circuit, wherein the AC-DC conversion circuit is electrically connected with the power frequency signal detection circuit; and the power frequency signal detection circuit is in signal connection with the optical coupling isolation output circuit. The zero-crossing detection circuit provided by the utility model solves the problem that a zero-crossing detection circuit in the prior art is poor in reliability and susceptible to interferences.

Description

A kind of zero cross detection circuit

Technical field

The utility model relates to electronic technology field, refers to a kind of zero cross detection circuit especially.

Background technology

Along with the fast development of power line carrier, PLC, the accurate detection of ac grid voltage zero crossing becomes very crucial, has only the zero passage of utilization point value, could realize the synchronism of carrier data transmission.General zero cross detection circuit is directly finished the transfer process of fixing level of the zero crossing of pulsating volage by triode, and directly output, and this circuit is too simple, and reliability is low, is subject to interference.

The utility model content

The utility model proposes a kind of zero cross detection circuit, it is low to have solved in the prior art reliability, the problem that is subject to disturb.

The technical solution of the utility model is achieved in that

A kind of zero cross detection circuit comprises: AC-DC change-over circuit, power frequency component testing circuit and light-coupled isolation output circuit; Wherein AC-DC change-over circuit and power frequency component testing circuit electrically connect; The power frequency component testing circuit is connected with light-coupled isolation output circuit signal.

Preferably, the power frequency component testing circuit comprises: capacitor C 21, C22, C23, C26; Optocoupler PT1, triode N7, transformer T1, diode D10, D11, VP1; Inductance L 6; Resistance R 14, R19, R20, R21, R23, R24, R25, R26; Wherein capacitor C 22 is electrically connected on the input end of optocoupler PT1, an end ground connection of capacitor C 22, and the other end connects power supply by resistance R 14, and resistance R 14 connects test interface with the connected node of capacitor C 22; Output first pin of optocoupler PT1 connects the collector of triode; Be connected diode D10 between the emitter of triode and the base stage, the grounded emitter of triode, base stage connects output after being electrically connected resistance R 21, R23, R24, R25 and the R26 of series connection successively; Output first pin of optocoupler PT1 connects resistance R 19, the R20 of series connection successively, the node that resistance R 19, R20 link to each other is by diode D11 ground connection, the earth terminal of diode D11 also is connected the two ends shunt capacitance C26 of capacitor C 23 by capacitor C 23 with the other end of resistance R 20; The node that resistance R 20 is connected with capacitor C 26 connects 4 pin of transformer T1; 2 pin of transformer T1 connect signal input part, 1 pin ground connection, and the inductance L 6 that 3 pin connect series connection successively connects output then with capacitor C 21, and the node that 3 pin are connected with inductance L 6 is by diode VP1 ground connection.

Preferably, diode D11 is 5.1V.

Preferably, the model of diode D10 is IN4148.

Preferably, the model of diode VP1 is P6KE22CA.

The utility model is constantly informed carrier chip in the mode of pulse by the power frequency component testing circuit with the zero passage of industrial-frequency alternating current, thereby for synchronous communication and phase judgment provide foundation, the accuracy of crossover point signal directly influences the effect of tdm communication, therefore but the utility model can provide reliability, is not subject to the zero cross detection circuit that disturbs.

Description of drawings

In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below, apparently, accompanying drawing in describing below only is embodiment more of the present utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the electronic circuit block diagram of a kind of zero cross detection circuit of the utility model;

Fig. 2 is the electronic circuit schematic diagram of the utility model power frequency component testing circuit.

Embodiment

Below in conjunction with the accompanying drawing among the utility model embodiment, the technical scheme among the utility model embodiment is clearly and completely described, obviously, described embodiment only is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making the every other embodiment that obtains under the creative work prerequisite, all belong to the scope of the utility model protection.

AC-DC change-over circuit 1(ac-dc converter circuit), power frequency component testing circuit 2 and light-coupled isolation output circuit 3 see also accompanying drawing 1 and accompanying drawing 2, a kind of zero cross detection circuit comprises:; Wherein AC-DC change-over circuit 1 electrically connects with power frequency component testing circuit 2; Power frequency component testing circuit 2 is connected with light-coupled isolation 3 output circuit signals.

Preferably, diode D11 is 5.1V.

Preferably, the model of diode D10 is IN4148.

Preferably, the model of diode VP1 is P6KE22CA.

Preferably, capacitor C 21 and transformer T1 in the utility model, effect be to be capacitor C 23, C26 charging when power frequency period, gather the electric flux into optocoupler conducting in the light-coupled isolation output circuit; Resistance R 20 and diode D11 also form mu balanced circuit, and D11 is the stabilivolt of a 5.1V, are 5V for the input voltage of stablizing optocoupler; Resistance R 21, R23, R24, R25 and diode D10 form bleeder circuit, and positive half period waveform is for triode N7 provides the suitable cut-in voltage moment; Triode N7 is used for amplifying the signal that zero crossing produces, and drives the optocoupler conducting; PT1 is common optocoupler, plays the photoelectricity buffer action, isolates forceful electric power and light current; Resistance R 14 is for optocoupler provides electric current, and capacitor C 22 can effectively be eliminated the interference on the line of electric force; And the utility model zero cross detection circuit has requirement equally to resistance capacitance: because the accuracy of crossover point signal directly influences the effect of tdm communication, and the precision of components and parts is depended in the accuracy of zero cross detection circuit, therefore the device precision of circuit is more high more good, but consider production cost simultaneously, therefore the precision that requires electric capacity is less than ± 10%, and the precision of resistance is less than ± 5%; For keeping all products consistance at zero point, 9014 of the long electricity of the triode N7 that adopts in this practicality, enlargement factor hFE must select B shelves (100～300) for use; Be chosen in IF=5mA for further adding the stiff stability optocoupler, VCE=5V, in the time of Ta=25 ℃, current transfer ratio is not less than 200%, is not less than 10 years serviceable life; The voltage stabilizing value of the model ZMM5V1 of D11 stabilivolt has determined the unlatching moment of triode N7 etc., in all devices of this part zero cross detection circuit, the parameter of stabilivolt is the most important, because the charging current of this circuit is very little, and the reverse steady current of powerful stabilivolt is bigger, so can not select powerful stabilivolt for use, specify 0.5W here.And the model of diode D10 is IN4148, and its unlatching that has determined triode N7 constantly etc. in all devices of the utility model zero cross detection circuit, is selected the diode with batch unanimity, and selected the IN4148 of long electricity for use; This was preferred forms of the present utility model at that time, but was not to be defined in this embodiment.

The above only is preferred embodiment of the present utility model; not in order to limit the utility model; all within spirit of the present utility model and principle, any modification of doing, be equal to replacement, improvement etc., all should be included within the protection domain of the present utility model.

Claims

1. a zero cross detection circuit is characterized in that, comprising: AC-DC change-over circuit, power frequency component testing circuit and light-coupled isolation output circuit; Wherein AC-DC change-over circuit and power frequency component testing circuit electrically connect; The power frequency component testing circuit is connected with light-coupled isolation output circuit signal.

2. a kind of zero cross detection circuit as claimed in claim 1 is characterized in that, the power frequency component testing circuit comprises: capacitor C 21, C22, C23, C26; Optocoupler PT1, triode N7, transformer T1, diode D10, D11, VP1; Inductance L 6; Resistance R 14, R19, R20, R21, R23, R24, R25, R26; Wherein capacitor C 22 is electrically connected on the input end of optocoupler PT1, an end ground connection of capacitor C 22, and the other end connects power supply by resistance R 14, and resistance R 14 connects test interface with the connected node of capacitor C 22; Output first pin of optocoupler PT1 connects the collector of triode; Be connected diode D10 between the emitter of triode and the base stage, the grounded emitter of triode, base stage connects output after being electrically connected resistance R 21, R23, R24, R25 and the R26 of series connection successively; Output first pin of optocoupler PT1 connects resistance R 19, the R20 of series connection successively, the node that resistance R 19, R20 link to each other is by diode D11 ground connection, the earth terminal of diode D11 also is connected the two ends shunt capacitance C26 of capacitor C 23 by capacitor C 23 with the other end of resistance R 20; The node that resistance R 20 is connected with capacitor C 26 connects 4 pin of transformer T1; 2 pin of transformer T1 connect signal input part, 1 pin ground connection, and the inductance L 6 that 3 pin connect series connection successively connects output then with capacitor C 21, and the node that 3 pin are connected with inductance L 6 is by diode VP1 ground connection.

3. a kind of zero cross detection circuit as claimed in claim 2 is characterized in that, diode D11 is 5.1V.

4. a kind of zero cross detection circuit as claimed in claim 2 is characterized in that, the model of diode D10 is IN4148.

5. a kind of zero cross detection circuit as claimed in claim 2 is characterized in that, the model of diode VP1 is P6KE22CA.