Summary of the invention
It is above-mentioned to solve that the purpose of this utility model is to provide a kind of ac solid relays with short-circuit protection
There are the problem of.
To achieve the above object, the technical solution adopted in the utility model are as follows: a kind of ac solid relay, including be used for
It is connected on the output switch circuit of load circuit, the output switch circuit includes two power switch tubes, the drive with short-circuit protection
Dynamic circuit and short-circuit detecting circuit, the power switch tube are that IGBT is managed or metal-oxide-semiconductor, two power switch tube differential concatenations are connected
Two output ends of the both ends afterwards as the ac solid relay, the driving circuit are powered by power circuit, the driving electricity
The input termination control signal on road, the on-off of two power switch tubes is correspondingly controlled according to control signal, and the driving circuit is same
When by short-circuit detecting circuit detection load whether short circuit, if short-circuit, then control two power switch tubes disconnection.
Further, two power switch tube is IGBT pipe T1 and T2, and the driving circuit is by two band short-circuit protections
IGBT driving chip IC1 and IC2 composition, IGBT driving chip IC1 and IC2 respectively drive IGBT pipe T1 and T2.
Further, the model of IGBT the driving chip IC1 and IC2 are IX2127, the IGBT driving chip
The H0 foot series resistance of IC1 connects the gate pole of IGBT pipe T1, and the H0 foot series resistance of the IGBT driving chip IC2 meets IGBT pipe T2
Gate pole, the emitter of IGBT the pipe T1 and T2 is connected with each other, and the collector of IGBT the pipe T1 and T2 are respectively as the friendship
Two output ends for flowing solid-state relay, for being serially connected in load circuit.
Further, the short-circuit detecting circuit is realized by bleeder circuit, and the bleeder circuit is for detecting the friendship
Flow solid-state relay two output ends voltage, the output end of the bleeder circuit respectively with IGBT driving chip IC1 and IC2
The connection of CS foot, IGBT driving chip IC1 and IC2 judge whether load is short-circuit by the voltage levels that CS foot inputs.
Further, the bleeder circuit includes diode D3, diode D5, resistance R1, resistance R4, resistance R6, electricity
The first end forward direction series diode D3 of resistance R8, resistance R2 and resistance R9, the resistance R1 connect the collector of IGBT pipe T1, described
The second end of resistance R1 is sequentially connected in series resistance R4 and R5 and connects signal ground, and the node between the resistance R1 and R4 connects IGBT driving core
The CS foot of piece IC1, the first end forward direction series diode D5 of the resistance R8 connect the collector of IGBT pipe T2, the resistance R8's
Second end is sequentially connected in series resistance R6 and R5 and connects signal ground, and the node between the resistance R8 and R6 connects IGBT driving chip IC2's
CS foot, the anode of the first terminating diode D3 of the resistance R2, the HO of the second termination IGBT driving chip IC1 of resistance R2
Foot, the anode of the first terminating diode of resistance R9 D5, the HO foot of the second termination IGBT driving chip IC2 of resistance R9.
It further, further include timing circuit, the timing circuit when driving circuit detects load short circuits for opening
Beginning timing exports enable signal to driving circuit after preset time-count cycle and drives the conducting of two power switch tubes.
Further, the timing circuit is realized using the timer IC3 of model MC14541B.
It further, further include optical coupling isolation circuit, the input termination control signal of the optical coupling isolation circuit, the light
The enable signal output end of first output termination timing circuit of coupling isolation circuit, the second output terminal of the optical coupling isolation circuit
Connect the input terminal of driving circuit.
Further, the power circuit is isolated DC/DC power circuit.
Further, further include resistance R15 and capacitor C8, the resistance R15 and capacitor C8 series connection be followed by this exchange it is solid
Between two output ends of state relay.
The advantageous effects of the utility model:
The utility model is common silicon-controlled using two IGBT or metal-oxide-semiconductor anti-series substitution, is protected using two band short circuits
The driving chip of shield respectively drives two IGBT or metal-oxide-semiconductor, the characteristic that can be actively turned off using IGBT or metal-oxide-semiconductor, realizes negative
The function of short-circuit protection, high reliablity, long service life are carried, and carry out periodic detection load short circuits failure using timing circuit to be
No disappearance, it is easy to use to restore normal operating conditions automatically after load short circuits failure vanishes, improve user experience.
The utility model circuit structure is simple, it is easy to accomplish, cost is relatively low.
Specific embodiment
Now in conjunction with the drawings and specific embodiments, the present invention will be further described.
A kind of ac solid relay, including for being connected on load circuit output switch circuit, optical coupling isolation circuit,
Power circuit and timing circuit, the output switch circuit include two power switch tubes, the driving circuit with short-circuit protection and short
Alignment detection circuit, the power switch tube are IGBT pipe or metal-oxide-semiconductor, itself are integrated with diode, two power switch tubes are reversely gone here and there
Connection, the both ends after series connection are used to be serially connected in load circuit as two output ends of the ac solid relay, the power supply electricity
Road is drive circuitry, and control signal is transferred to driving circuit by optical coupling isolation circuit isolation, and driving circuit is according to control
Signal correspondingly controls the on-off of two power switch tubes, and whether the driving circuit detects load by short-circuit detecting circuit simultaneously
Short circuit then controls the disconnection of two power switch tubes if short-circuit.
Timing circuit is for starting timing when driving circuit detects load short circuits, after preset time-count cycle
It exports enable signal and drives the conducting of two power switch tubes to driving circuit.If the short trouble loaded at this time has been removed,
The ac solid relay will start to work normally;, whereas if load is still in short trouble at this time, driving circuit is logical
It crosses short-circuit detecting circuit and detects load short circuits again, then two power switch tube of secondary control disconnects, timing circuit starts new timing,
Terminate until a new time-count cycle, exports enable signal again to driving circuit and drive the conducting of two power switch tubes, so
Circulation.
As shown in Fig. 2, power switch tube is preferably IGBT pipe, i.e. IGBT pipe T1 and T2, itself collection in this specific embodiment
At diode, the emitter of IGBT pipe T1 and T2 are connected with each other, the node series electrical between the emitter of IGBT pipe T1 and T2
Resistance R5 connects signal ground, and the collector of IGBT pipe T1 and T2 are used for respectively as two output ends 1 and 2 of the ac solid relay
It is serially connected in load circuit, certainly, in other implementations, power switch tube is also possible to metal-oxide-semiconductor, this is those skilled in the art
It can realize, no longer describe in detail easily.
As shown in Fig. 2, the driving circuit is by two IGBT driving chips with short-circuit protection in this specific embodiment
IC1 and IC2 composition, the model of IGBT the driving chip IC1 and IC2 are IX2127, the H0 of the IGBT driving chip IC1
Foot series resistance R3 connects the gate pole of IGBT pipe T1, and the H0 foot series resistance R7 of the IGBT driving chip IC2 connects IGBT pipe T2's
Gate pole is connected to zener diode D6 between the gate pole and emitter of IGBT pipe T1, protects to IGBT pipe T1, the IGBT pipe
It is connected to zener diode D7 between the gate pole and emitter of T2, IGBT pipe T2 is protected, certainly, in other embodiments,
IGBT driving chip IC1 and IC2 can also use other IGBT driving chips with short-circuit protection, this is those skilled in the art
It can realize, no longer describe in detail easily.
In this specific embodiment, the short-circuit detecting circuit is realized by bleeder circuit, and the bleeder circuit is for detecting
The voltage of two output ends 1 and 2 of the ac solid relay, the output end of the bleeder circuit respectively with IGBT driving chip
IC1 is connected with the CS foot of IC2, and IGBT driving chip IC1 and IC2 may determine that load is by the voltage levels that CS foot inputs
No short circuit, this is because when the ac solid relay is in the conductive state, and load and short circuit occurs, at this point, output loop
Electric current will be increased sharply, cause the voltage of two output ends 1 and 2 of the ac solid relay will be with the increasing of output loop electric current
Add and increases.
Specifically, as shown in Fig. 2, the bleeder circuit includes diode D3, diode D5, resistance R1, resistance R4, resistance
R6, resistance R8, resistance R2 and resistance R9, the resistance R1 first end forward direction series diode D3 connect the collector of IGBT pipe T1
(output end 1 of the ac solid relay), the second end of the resistance R1 is sequentially connected in series resistance R4 and R5 and connects signal ground, described
Node between resistance R1 and R4 connects the CS foot of IGBT driving chip IC1, the first end forward direction series diode of the resistance R8
D5 connects the collector (output end 2 of the ac solid relay) of IGBT pipe T2, and the second end of the resistance R8 is sequentially connected in series electricity
Resistance R6 and R5 connects signal ground, and the node between the resistance R8 and R6 meets the CS foot of IGBT driving chip IC2, the resistance R2
The first terminating diode D3 anode, the HO foot of the second termination IGBT driving chip IC1 of resistance R2, the resistance R9 the
The anode of one terminating diode D5, the HO foot of the second termination IGBT driving chip IC2 of resistance R9.
As shown in Figure 1, power circuit is isolated DC/DC power circuit in this specific embodiment, it is highly-safe, specifically
Including isolated DC/DC converter S1 and diode D1, the input anode Vin of the isolated DC/DC converter S1 is reversely gone here and there
Union II pole pipe D1 meets input power, the input negative terminal GND ground connection of the isolated DC/DC converter S1, the isolated DC/DC
Output plus terminal+the Vo of converter S1 connects the VCC foot of IGBT driving chip IC1 and IC2, the isolated DC/DC converter respectively
The output negative terminal 0V of S1 connects signal ground.Certainly, in other embodiments, power circuit can also be using existing other power supply electricity
Road, this is that those skilled in the art can realize easily, is no longer described in detail.
As shown in figure 4, the timing circuit uses the programmable timer of model MC14541B in this specific embodiment
IC3 realizes that the VDD foot of timer IC3 meets the output plus terminal+Vo of the isolated DC/DC converter S1, timer IC3's
MR foot connects the F foot of IGBT driving chip IC1 and IC2 simultaneously, and the Q foot of timer IC3 is enable signal output pin, timer IC3
The circuit connections of other pins be detailed in Fig. 4, this is no longer described in detail so that when timer IC3 is started counting, the Q of timer IC3
Foot exports low level, and after timer IC3 is counted, the Q foot of timer IC3 exports high level (enable signal).Certainly, exist
In other embodiments, when also can be set as needed timer IC3 and starting counting, the Q foot of timer IC3 exports high level,
After timer IC3 is counted, the Q foot of timer IC3 exports low level, this is that those skilled in the art can realize easily
, no longer describe in detail.
Certainly, in other embodiments, timing circuit can also use existing other timing circuits, this is this field skill
What art personnel can realize easily, no longer describe in detail.
As shown in figure 3, optical coupling isolation circuit includes optocoupler P1 and NPN triode T1, the optocoupler in this specific embodiment
P1 is made of light emitting diode and phototriode, and the anode series resistance R10 of the light emitting diode of the optocoupler P1 connects
Control signal, the negativing ending grounding of the light emitting diode of the optocoupler P1, the collector of the phototriode of the optocoupler P1
The Q foot of timer IC3 and the collector of NPN triode T1 are connect, the emitter of the phototriode of the optocoupler P1 connects tri- pole NPN
The base stage of pipe T1, the emitter of the NPN triode T1 connects the IN foot of IGBT driving chip IC1 and IC2, while passing through parallel connection
Resistance R11 and capacitor C5 connect signal ground.Certainly, in other embodiments, optical coupling isolation circuit can also use existing other
Optical coupling isolation circuit, this is that those skilled in the art can realize easily, is no longer described in detail.
It further include that resistance R15 and capacitor C8, the resistance R15 and capacitor C8 series connection are followed by this in this specific embodiment
Between two output ends 1 and 2 of ac solid relay, resistance R15 and capacitor C8 constitute resistance-capacitance absorption circuit, improve IGBT pipe T1
With survival ability of the T2 under surge.
The course of work:
When normal work: when the front end resistance R10 is to control signal, optocoupler P1 conducting, the Q foot output of timing circuit at this time
High level, then the IN foot of IGBT driving chip IC1 and IC2 is in high level, the H0 foot output of IGBT driving chip IC1 and IC2
High level drives IGBT pipe T1 and T2 conducting, then output loop is connected, and the ac solid relay is in the conductive state.When defeated
When entering the control signal at end and removing, optocoupler P1 is disconnected, then the IN foot of IGBT driving chip IC1 and IC2 be in low level, IGBT drive
The H0 foot of dynamic chip IC 1 and IC2 export low level, then IGBT pipe T1 and T2 are turned off, which is off shape
State.
Short-circuit protection principle: when the ac solid relay is in the conductive state, and loading and short circuit occur, at this point, output
The electric current in circuit will be increased sharply, and the voltage of two output ends 1 and 2 of the ac solid relay will be with output loop electric current
Increase and increase, when voltage increase when, the voltage of the CS foot of IGBT driving chip IC1 and IC2 also rises, once on the voltage
When rising certain value, IGBT driving chip IC1 and IC2 are judged as load short circuits, the H0 foot of IGBT driving chip IC1 and IC2 it is defeated
It will be rapidly decreased to zero from normal high level out, so that IGBT pipe T1 and T2 switchs to closed state from state, entrance is short
Road guard mode avoids IGBT pipe T1 and T2 from damaging because of excessive short circuit current.Meanwhile IGBT driving chip IC1 and IC2
F foot is by the MR foot of device IC3 when exporting a signal feeding, so that timing circuit is started to work, the Q foot of timer IC3 is by high electricity
Flat turn is low level, and the IN foot of IGBT driving chip IC1 and IC2 are in low level, drives IGBT pipe T1 and T2 shutdown, works as timing
At the end of, the Q foot of timer IC3 switchs to high level by low level, and the IN foot of IGBT driving chip IC1 and IC2 are in high level,
IGBT pipe T1 and T2 conducting is driven, if the short trouble loaded at this time has been removed, which will start
It works normally;, whereas if load is still in short trouble at this time, then the ac solid relay enters short-circuit protection again
State terminates until a new time-count cycle, then judges whether load is still within short-circuit condition, so recycles.
The utility model is common silicon-controlled using two IGBT pipe T1 and T2 anti-series substitutions, is protected using two band short circuits
IGBT the driving chip IC1 and IC2 of shield respectively drive IGBT pipe T1 and T2, the spy that can be actively turned off using IGBT pipe T1 and T2
Property, realize the function of load short circuits protection, high reliablity, long service life, and periodic detection load is carried out using timing circuit
Whether short trouble disappears, easy to use to restore normal operating conditions automatically after load short circuits failure vanishes, improves
User experience, and circuit structure is simple, it is easy to accomplish, cost is relatively low.
Certainly, in other embodiments, it is saving cost, timing circuit can also be cancelled, but cancel timing circuit, then
It can not carry out whether periodic detection load short circuits failure disappears, to restore normal work automatically after load short circuits failure vanishes
Make state.
Although specifically showing and describing the utility model in conjunction with preferred embodiment, those skilled in the art is answered
This is understood, in the spirit and scope for not departing from the utility model defined by the appended claims, in form and details
On the utility model can be made a variety of changes, be the protection scope of the utility model.