Background technology
Charger is commonly referred to as a kind of equipment that alternating current is converted to low-voltage DC.Charger is to adopt power electronics semiconductor device, and voltage and the constant alternating current of fixed-frequency are transformed to galvanic a kind of static ac dc converter device.Charger is of many uses in every field, particularly is widely used in common electrical equipment such as mobile phone, camera at sphere of life.Therefore along with various such as mobile phone extensively the popularizing of appliance applications, the use amount of each electrical equipment is increasing, makes that the use that is used for the charger on the various electrical equipment is also extensive all the more, has become an indispensable part in the electrical equipment industry.
Along with the widespread use of charger, each production firm all can detect it before charger dispatches from the factory for the quality of raising charger and the security of use.Charger testing circuit commonly used now generally includes input circuit, DC power supply circuit, buffer circuit, amplifying circuit, driving circuit and on-off circuit; Described input circuit is connected with the external commercial power power supply, and described input circuit is provided with socket, so that charger to be detected is connected on the described input circuit, with convenient described charger to be detected is carried out detecting operation; Described buffer circuit is electrically connected with described input circuit, DC power supply circuit and amplifying circuit respectively, influences each other to isolate described DC power supply circuit and input circuit, to prevent in the input circuit mains supply and the direct supply that are connect; Described DC power supply circuit is given described amplifying circuit power supply, to assist to finish detecting operation; Described driving circuit is electrically connected with described amplifying circuit and on-off circuit respectively, to drive described on-off circuit work; Described on-off circuit is controlled the break-make of whole testing circuit, thus the beginning of control detection operation.When carrying out detecting operation, after inserting charger to be detected in the socket, whole testing circuit is conducting at once then, and photoelectrical coupler will produce bigger electric current in energising moment in the described buffer circuit, even produces the situation of electric spark and damage the pin and the testing circuit of charger; And moment bigger electric current also may damage the on-off circuit of back, make make a mistake action and can not get testing result accurately of on-off circuit.
Therefore, be necessary to provide a kind of improved charger testing circuit to overcome above-mentioned defective, avoid contacting moment generation electric spark.
The utility model content
The purpose of this utility model provides a kind of charger testing circuit, and this charger detects electrical equipment and can effectively avoid producing electric spark when charger inserts, has strengthened the security of use, has avoided charger and testing circuit to be damaged by electric spark in insertion moment.
For achieving the above object, the utility model provides a kind of charger testing circuit, this charger testing circuit comprises input circuit, DC power supply circuit, buffer circuit, amplifying circuit, driving circuit and on-off circuit, described input circuit is connected with the external commercial power power supply, described input circuit is provided with socket, so that charger to be detected is connected on the described input circuit, described buffer circuit respectively with described input circuit, DC power supply circuit and amplifying circuit are electrically connected, to isolate described DC power supply circuit and input circuit, described DC power supply circuit is given described amplifying circuit power supply, described driving circuit is electrically connected with described amplifying circuit and on-off circuit respectively, to drive described on-off circuit work, described on-off circuit is electrically connected with described input circuit, to control the break-make of whole testing circuit, wherein, also comprise a delay circuit, described delay circuit is electrically connected to control the work of described amplifying circuit with described amplifying circuit.
Preferably, described amplifying circuit comprises first amplifier and second amplifier, and described delay circuit is installed between the in-phase input end of the difference output end of described first amplifier and second amplifier.
Preferably, described delay circuit comprises pressure release diode, current-limiting resistance and delay capacitor, described pressure release diode and current-limiting resistance are connected in parallel and are connected between the in-phase input end of the difference output end of described first amplifier and second amplifier, described delay capacitor one end is connected other end ground connection with the in-phase input end of described second amplifier.
Preferably; described on-off circuit comprises field effect transistor and relay; described field effect transistor is electrically connected with described driving circuit and relay respectively; to control the adhesive of described relay; the normally opened contact of described relay is connected with described input circuit, and the normally opened contact of a protective resistance and described relay is connected in parallel.
Compared with prior art, described charger testing circuit of the present utility model is owing to also comprise that a delay circuit, described delay circuit are electrically connected with described amplifying circuit to control the work of described amplifying circuit; Thereby described delay circuit may command delays the conducting work of described amplifying circuit, to delay the conducting of whole testing circuit, therefore when charger to be detected is inserted on the testing circuit of the present utility model, whole testing circuit is conducting immediately not, but slowly conducting under the effect of described delay circuit, effectively avoided the moment conducting to cause electric current excessive and produce the situation of electric spark
By following description also in conjunction with the accompanying drawings, it is more clear that the utility model will become, and these accompanying drawings are used to explain embodiment of the present utility model.
Embodiment
With reference now to accompanying drawing, describe embodiment of the present utility model, the similar elements label is represented similar elements in the accompanying drawing.As mentioned above, the utility model provides a kind of charger testing circuit, this charger detects electrical equipment and can effectively avoid producing electric spark when charger inserts, has strengthened the security of use, has avoided charger and testing circuit to be damaged by electric spark in insertion moment.
Please refer to Fig. 1, Fig. 1 is the theory diagram of the utility model charger testing circuit.As shown in the figure, the utility model charger testing circuit comprises input circuit 110, DC power supply circuit 140, buffer circuit 120, amplifying circuit 130, delay circuit 150, driving circuit 160 and on-off circuit 170; Described input circuit 110 is connected with the external commercial power power supply, because charger power supply that connects when charging normal is a mains supply, therefore provides mains supply whether to meet the operate as normal requirement to detect charger; Described buffer circuit 120 is electrically connected with described input circuit 110, DC power supply circuit 140 and amplifying circuit 130 respectively, to isolate described DC power supply circuit 140 and input circuit 110, prevent that the mains supply and the direct supply 140 that are connect in the input circuit 110 from influencing each other; Described delay circuit 150 is electrically connected with described amplifying circuit 130 to control the work of described amplifying circuit 130, can be in the instantaneous conducting of charger insertion to be detected to control whole testing circuit; Described direct supply; The described driving circuit 160 in back is electrically connected with described amplifying circuit 130 and on-off circuit 170 respectively, and to drive described on-off circuit 170 work, described on-off circuit 170 is electrically connected with described input circuit 110, to control the break-make of whole testing circuit.
Particularly, please again in conjunction with reference to figure 2.Described input circuit 110 is connected with the electric main of extraneous 220V, and described input circuit 110 is provided with socket XS, so that charger to be detected is connected on the described input circuit 110, and makes whole testing circuit form complete loops; Described input circuit 110 also is provided with rectifier bridge D101 and resistance R 1, and described resistance R 1 resistance is bigger, can effectively control the magnitude of voltage that is added in described rectifier bridge D101 two ends; Described rectifier bridge D101 is a direct current with the AC rectification of input, and output voltage is clamped at about 1.4V under voltage stabilizing diode D1 and D2 effect, thinks that subsequent conditioning circuit provides stable input voltage.
Described DC power supply circuit 140 is connected with described buffer circuit 120 and amplifying circuit 130 respectively, and described DC power supply circuit 140 comprises three terminal regulator IC1 and filter capacitor C2, C3, described three terminal regulator IC1 is 7805 serial voltage stabilizers, and is connected with extraneous 12V direct supply; The voltage of described three terminal regulator IC1 output is through being added to after described filter capacitor C2 and the C3 filtering on described buffer circuit 120 and the amplifying circuit 130.
Described buffer circuit 120 is connected in the output terminal of described rectifier bridge D101, and the main element of described buffer circuit 120 is photoelectrical coupler PHC01.The voltage of described rectifier bridge D101 output is added on the interior light emitting diode of described photoelectrical coupler PHC01, makes described light emitting diode conducting luminous; Triode in the described photoelectrical coupler PHC01 is connected with the output terminal of described three terminal regulator IC1, described three terminal regulator IC is this triode power supply, after the light emitting diode conducting in the described photoelectrical coupler PHC01, the 5V voltage of this triode conducting and output, the 5V voltage of output is added on the described amplifying circuit 130 by after resistance R 2 and the R3 dividing potential drop.Said, in the utility model embodiment, described buffer circuit 120 has effectively been isolated DC power supply circuit 140 and the AC power that input circuit 110 is connected, and prevents both influencing each other.
Described amplifying circuit 130 comprises the first amplifier ICL1 and the second amplifier ICL2, the voltage of the triode output in the described photoelectrical coupler PHC01 is added on in-phase input end 3 pin of the described first amplifier ICL1 after described resistance R 2 and R3 dividing potential drop, the voltage of described three terminal regulator IC1 output is added on inverting input 2 pin of the described first amplifier ICL1 after resistance R 4 and R5 dividing potential drop, the described first amplifier ICL1 compares the voltage of inverting input and the voltage of in-phase input end, when 3 pin voltages are higher than 2 pin voltages, by its difference output end 1 pin output high level, and this high level is added on in-phase input end 5 pin of the described second amplifier ICL2; The voltage of described three terminal regulator IC1 output is added on inverting input 6 pin of the described second amplifier ICL2 after resistance R 7 and R8 dividing potential drop, the described second amplifier ICL2 compares the voltage of its inverting input and the voltage of in-phase input end, when 5 pin voltages are higher than 6 pin voltages, export high level to described driving circuit 160 by its difference output end 7 pin.Wherein, described delay circuit 150 is connected between in-phase input end 5 pin of difference output end 1 pin of the described first amplifier ICL1 and the second amplifier ICL2; Particularly, described delay circuit 150 comprises pressure release diode D3, current-limiting resistance R6 and delay capacitor C1, described pressure release diode D3 and current-limiting resistance R6 are connected in parallel and are connected between in-phase input end 5 pin of difference output end 1 pin of the described first amplifier ICL1 and the second amplifier ICL2, and described delay capacitor C1 one end is connected other end ground connection with in-phase input end 5 pin of the described second amplifier ICL2; Thereby the voltage of difference output end 1 pin of described first amplifier ICL1 output is earlier described capacitor C 1 charging, have only when the magnitude of voltage on the described capacitor C 1 during greater than the magnitude of voltage on inverting input 6 pin of the described second amplifier ICL2, difference output end 7 pin of the described second amplifier ICL2 just can be exported high level, can make the driving circuit 160 conducting work of back, therefore delayed the action of the on-off circuit 170 of described driving circuit 160 and back thereof, that is to say the ON time that has delayed whole testing circuit, insert the moment of this testing circuit owing to be in not conducting state when charger to be detected, so the situation of electric spark can not take place, can not damage the pin of charger; After charger that detection finishes pulled away, described capacitor C 1 was discharged to described diode D3 because of dead electricity, and described diode D3 is equivalent to let out load, electric charge on the described capacitor C 1 is discharged finish, to prepare to carry out the next round detecting operation.
Described driving circuit 160 comprises triode Q1 and Q2, when difference output end 7 pin of the described second amplifier ICL2 are exported high level, and described triode Q1 and Q2 conducting in succession, and output 12V voltage; When described triode Q1 and Q2 will drive described on-off circuit 170 actions after the conducting.
Described on-off circuit 170 is electrically connected with described driving circuit 160 and input circuit 110 respectively, described on-off circuit 170 comprises field effect transistor Q101 and relay K T, the normally opened contact K1 of described relay K T is connected in the described input circuit 110, and in parallel with described resistance R 2; After described triode Q2 conducting, 12V voltage is added to the grid of described field effect transistor Q101, make described field effect transistor Q101 conducting, thereby the coil of described relay K T gets electric its normally opened contact K1 closure that makes, with with described resistance R 2 short circuits, therefore the alternating current of civil power 220V all is added to the two ends of described charger to be detected, so that described charger to be detected can normally carry out detecting operation.
As mentioned above, charger testing circuit of the present utility model is in testing process, when charger to be detected inserts described socket XS because entire circuit is in not conducting state, and the effect of described resistance R 2 makes that the magnitude of voltage that is added in its two ends is smaller, therefore can instantaneous contact and produce electric spark, strengthened the security of using, avoided charger and testing circuit to be damaged by electric spark in insertion moment.
Abovely the utility model is described, but the utility model is not limited to the embodiment of above announcement, and should contains various modification, equivalent combinations of carrying out according to essence of the present utility model in conjunction with most preferred embodiment.