CN202268861U - Switching circuit - Google Patents
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- CN202268861U CN202268861U CN2011204059627U CN201120405962U CN202268861U CN 202268861 U CN202268861 U CN 202268861U CN 2011204059627 U CN2011204059627 U CN 2011204059627U CN 201120405962 U CN201120405962 U CN 201120405962U CN 202268861 U CN202268861 U CN 202268861U
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Abstract
The utility model discloses a switching circuit, which can reduce requirement of products for a space, improve flexibility of product design and prolong service life of products and is high in anti-disturbance performance and reliable in performance. An embodiment of the switching circuit comprises a trigger button, a semi-conductor controlling device and a switching tube. When the switching circuit is in a disconnected state and the trigger button is triggered, the switching tube is connected, the switching circuit is converted into a connected state from a disconnected state, and the semi-conductor controlling device is connected. The connected semi-conductor controlling device keeps the connected state of the switching circuit. When the switching circuit is in the connected state and the trigger switch is triggered, current passing through the semi-conductor controlling device is by-passed, and the semi-conductor controlling device is closed. After the trigger switch is bounced up, the switching tube is closed, and when the switching tube is closed, the switching circuit is converted into a disconnected state from a connected state.
Description
Technical field
The utility model relates to the semiconductor application technical field, especially relates to a kind ofly can realizing the reliable break-make of power supply, switching circuit simple in structure.
Background technology
Switching circuit is the part that most systems must use, and is used to connect or turn-off the power supply between general supply and the system, perhaps the relation of the power supply between control system power supply and the subsystem.
In the existing switching circuit, mainly contain following two kinds of schemes: first kind of scheme directly adopts mechanical limit switch, through mechanical movement, makes circuit be in conducting or off-state physically; Second kind of scheme is to adopt complicated chip to make special control switch circuit; Realize conducting or disconnection between the input and output (IO); Perhaps adopt microprogram control unit (Microprogrammed Control Unit; MCU) with the trigger button combination, with the state of trigger button control MCU and then connection or the disconnection between the realization input and output.
Yet there are many weak points in existing switching circuit, for example,
To first kind of scheme, the general volume of mechanical limit switch is relatively large, is not easy on the structure to realize; Operation is relatively complicated; And there is electromagnetic interference in the moment that connected sum breaks off, and (useful life is shorter relatively for Electro-Magnetic Interference, problem EMI); Its structural design is higher to space requirement, has influenced the flexibility of global switch circuit structure design;
Than first kind of scheme; Second kind of scheme can reduce switching circuit and take up space, but the switching circuit of second kind of scheme needs special control chip or MCU, and required hardware cost is higher relatively; Circuit complexity is big, the work that also needs extra code to write.And; Because the input of trigger button or the IO of MCU itself are very sensitive to voltage; The probability that causes occurring the electrostatic induction phenomenon is higher, be difficult to realize static discharge (Electro-Static discharge, ESD); Make product face Electro Magnetic Compatibility (Electro Magnetic Compatibility, EMC) relatively poor problem.
The utility model content
The utility model embodiment provides a kind of switching circuit, can reduce the requirement of product to the space, improves the flexibility and the useful life of product design, and improves the interference free performance of product.
For achieving the above object, the technical scheme of the utility model embodiment is achieved in that
The utility model embodiment provides a kind of switching circuit; This switching circuit comprises trigger button, semiconductor control device and switching tube; Wherein, the input of above-mentioned switching tube is connected with DC power supply, and above-mentioned control end of switching tube is connected with DC power supply through first resistance; Above-mentioned output end of switching tube is connected with load, and above-mentioned trigger button, semiconductor control device are connected to above-mentioned control end of switching tube;
Under switching circuit was in off-state, above-mentioned trigger button received when triggering, above-mentioned switching tube conducting, and said switching circuit switches to opening from off-state, and the conducting of above-mentioned semiconductor control device;
The above-mentioned opening of the semiconductor control device maintained switch circuit after the conducting;
Under switching circuit was in opening, above-mentioned trigger button received when triggering, and above-mentioned semiconductor control device turn-offs, and when above-mentioned switching tube broke off, said switching circuit switched to off-state from opening.
Further, above-mentioned semiconductor control device is a silicon controlled rectifier, and perhaps, above-mentioned semiconductor control device is the combination of two triodes, and the combination of above-mentioned two triodes comprises a NPN type triode and the second positive-negative-positive triode.
Further, said switching circuit also comprises the 4th resistance, and when above-mentioned semiconductor control device was the triode combination, the base stage of the collector electrode of the above-mentioned second positive-negative-positive triode and a NPN type triode was connected the back through above-mentioned the 4th grounding through resistance.
Further, said switching circuit also comprises the 3rd resistance, and when above-mentioned semiconductor control device was the triode combination, the emitter of an above-mentioned NPN type triode was through above-mentioned the 3rd grounding through resistance.
Further, said switching circuit also comprises second electric capacity, and above-mentioned second electric capacity is connected in parallel on above-mentioned the 4th resistance two ends, and the positive pole of above-mentioned second electric capacity links to each other the minus earth of above-mentioned second electric capacity with the base stage of an above-mentioned NPN type triode.
Further; Said switching circuit also comprises first electric capacity and the 7th resistance; Above-mentioned first electric capacity and the 7th resistance are connected in parallel between above-mentioned trigger button and the above-mentioned control end of switching tube; Wherein, the positive pole of above-mentioned first electric capacity links to each other with above-mentioned control end, and the negative pole of above-mentioned first electric capacity links to each other with above-mentioned trigger button.
Further, the appearance value of above-mentioned first electric capacity is greater than the appearance value of above-mentioned second electric capacity.
Further, said switching circuit also comprises the 4th electric capacity and the 5th resistance, and an end of above-mentioned the 5th resistance is connected to above-mentioned output end of switching tube, and the other end of above-mentioned the 5th resistance is connected to the positive pole of above-mentioned the 4th electric capacity, the minus earth of above-mentioned the 4th electric capacity.
Further; Said switching circuit also comprises the 3rd NPN type triode; The collector electrode of above-mentioned the 3rd NPN type triode is connected with above-mentioned trigger button, the grounded emitter of above-mentioned the 3rd NPN type triode, and the base stage of above-mentioned the 3rd NPN type triode is through above-mentioned the 4th capacity earth.
Further, said switching circuit also comprises the 8th resistance, and when above-mentioned semiconductor control device was the combination of two triodes, above-mentioned trigger button was connected through the base stage of above-mentioned the 8th resistance with a NPN type triode.
By above-mentioned visible, the utility model embodiment utilizes trigger button collocation semiconductor control device and switching tube, and a kind of novel switching circuit is provided, and can realize the reliable break-make of power supply.
The present technique scheme adopts trigger button; Thereby relatively mechanical limit switch has smaller volume and profile flexibly; Reduced the requirement of product, improved the flexibility of product design, operated easy more laborsaving the space; And the EMI problem of having avoided mechanical limit switch to cause in the moment that connected sum breaks off, the useful life of having improved product.
And the present technique scheme need not complicated control chip or MCU, the work of having avoided extra code to write; The device that adopts is the most common semiconductor device commonly used; Simple in structure, significantly reduced hardware cost and development cost, have higher feasibility;
Further, each device is insensitive to static in the switching circuit that the present technique scheme provides, and interference free performance is quite high; Dependable performance; In practice, this programme can access desirable ESD test result, and long by with the situation of pressing trigger button fast under also can realize not having misoperation.
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; Obviously, the accompanying drawing in describing below only is some embodiment of the 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.
The structural representation of a kind of switching circuit that Fig. 1 provides for the utility model embodiment one;
The sketch map of a kind of switching circuit structure that Fig. 2 provides for the utility model embodiment two;
Triode combination that Fig. 3 provides for the utility model embodiment two and silicon controlled equivalence replacement schematic diagram;
Operation principle sketch map under the switching circuit start operator scheme that Fig. 4 provides for the utility model embodiment three;
The switching circuit that Fig. 5 provides for the utility model embodiment three turn-offs the operation principle sketch map under the operator scheme.
Embodiment
The accompanying drawing that will combine the utility model below carries out clear, intactly description to the technical scheme of the utility model, and obviously, described embodiment only is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, the every other embodiment that those of ordinary skills are obtained under the prerequisite of not making creative work belongs to the scope that the utility model is protected.
The utility model embodiment one provides a kind of switching circuit; Referring to Fig. 1; Said switching circuit comprises trigger button S1, semiconductor control device and switching tube Q4, and said switching tube comprises input 11, output 12 and control end 13, when the voltage difference between input 11 and the control end 13 satisfies unlocking condition; Conducting between the input 11 of said switching tube and the output 12, promptly said switching tube conducting;
Said input 11 is connected with DC power supply; Said control end 13 is connected with DC power supply through first resistance R 1 (abbreviating resistance R 1 as); Said output 12 is connected with load, and said trigger button, semiconductor control device are connected to said control end 13;
Under switching circuit is in off-state; Said trigger button receives when triggering; The voltage of said control end 13 changes, and the voltage difference between said input 11 and control end 13 satisfies unlocking condition, said switching tube conducting; Said switching circuit switches to opening from off-state, and the conducting of said semiconductor control device;
Semiconductor control device after the conducting can keep the unlocking condition of said switching tube, i.e. the said opening of the semiconductor control device maintained switch circuit after the conducting;
Under switching circuit was in opening, said trigger button received when triggering, and the voltage of said control end 13 changes; The electric current that flows through the semiconductor control device is by bypass; Said semiconductor control device turn-offs, and the voltage difference between said input 11 and the control end 13 does not satisfy unlocking condition, and said switching tube breaks off; When said switching tube broke off, said switching circuit switched to off-state from opening.
Further; Above-mentioned semiconductor control device can be silicon controlled rectifier, perhaps, can be realized by the combination of two triodes; This triode combination comprises a positive-negative-positive triode and a NPN type triode, like a NPN type triode Q1 and the second positive-negative-positive triode Q2.
Further, above-mentioned switching tube Q4 can be the metal-oxide-semiconductor of P type, and perhaps, above-mentioned switching tube Q4 can be the positive-negative-positive triode.
For the ease of the clear technical scheme of describing the utility model embodiment; In each embodiment of utility model; Adopted printed words such as " first ", " second " that function is distinguished with essentially identical identical entry of effect or similar item, it will be appreciated by those skilled in the art that printed words such as " first ", " second " do not limit quantity and execution order.
The switching circuit that provides in the face of the utility model embodiment two down describes.Present embodiment provides a kind of have lower cost, high performance switching circuit, and it has overcome the deficiency of existing scheme, existing relatively scheme, and this switching circuit is in very high superiority of each Fang Junyou such as space hold, circuit complexity, Costco Wholesale, reliabilities.Referring to Fig. 2, comprise importation, switching circuit portion and output in the example of the switching circuit structure that the utility model embodiment two provides.
As shown in Figure 2, frame of broken lines 1 is importation (or being called power unit), the i.e. input of this exemplary circuit; Power supply is the example explanation with the battery in this example; Anode connects the input of switching circuit portion, and GND is the ground level of this exemplary circuit, is called for short ground.Frame of broken lines 3 is an output, and output inserts load, and this example is connected as load with the 6th resistance R 6 (being called for short resistance R 6) and light-emitting diode D1, and resistance R 6 links to each other the D1 minus earth as the current-limiting resistance of light-emitting diode D1 with the D1 anode.The power supply that the input part branch provides is appreciated that the device that is comprised in the above-mentioned load, can chooses the device of other required power supplies arbitrarily, as long as can satisfy the power demands of these devices.
Frame of broken lines 2 is a switching circuit portion, is used to control the conducting and the disconnection of circuit between importation and the output.Switching circuit portion is the core of this programme, and the switching circuit that constitutes switching circuit portion comprises trigger button, triode combination or controllable silicon, and switching tube, resistance and electric capacity are realized the dual-use function of switch on and off jointly by these devices.Below mainly each device and operation principle thereof in the switching circuit are described.
Switching tube
Above-mentioned switching tube; Be used for controlled connection or break off the operation between importation and the output; Promptly be communicated with importation and output, power supply powered to the load, perhaps through the control switch pipe; Break off importation and output through the control switch pipe, power supply is no longer powered to the load.
Above-mentioned switching tube is the semiconductor device of one three end, and three ends of this switching tube comprise input, output and control end, when the voltage difference between input and the control end satisfies unlocking condition, and conducting between the input of said switching tube and the output.
Preferably, adopt a P type metal-oxide-semiconductor as switching tube in the present embodiment, label is Q4.The source electrode of metal-oxide-semiconductor Q4 (S) is the input of switching tube (or switching circuit), directly is connected with power supply, and the drain electrode of metal-oxide-semiconductor Q4 (D) is the load of switching tube (or switching circuit) output termination.The grid of metal-oxide-semiconductor Q4 (G) links to each other with power supply through resistance R 1 as control end of switching tube.The source electrode that is metal-oxide-semiconductor Q4 is the input of switching tube, and the drain electrode of metal-oxide-semiconductor Q4 is an output end of switching tube, and the grid of metal-oxide-semiconductor Q4 is a control end of switching tube.
Control end also is connected with second resistance R 2 (being called for short resistance R 2) among Fig. 2, and optional to play metering function, this resistance R 2 can be omitted, and substitutes with lead, resistance R 2 two ends all is called the grid (G) of metal-oxide-semiconductor Q4 at this.
Optional; Can also adopt a positive-negative-positive triode as above-mentioned switching tube in the present embodiment; The emitter of this positive-negative-positive triode is as the input of switching tube, and the collector electrode of this positive-negative-positive triode is as output end of switching tube, and the base stage of this positive-negative-positive triode is as control end of switching tube.
The semiconductor control device
Above-mentioned semiconductor control device can be realized by silicon controlled rectifier (abbreviating controllable silicon as).In the silicon controlled operation principle, its turn-on condition is that anode (A) adds enough positive voltages and the control utmost point (G) adds a positive voltage, when both exist simultaneously, and the controllable silicon conducting.After the controllable silicon conducting, there is no-voltage not influence its lasting conducting state in the control extremely.Its condition that opens circuit is the anode voltage disappearance or flows through the silicon controlled electric current less than its lasting conducting electric current, can both change the silicon controlled state so turn-off the supply of anode voltage or the controllable silicon anode current is switched to both any operations of ground.
Above-mentioned semiconductor control device also can be realized by substituting the combination of silicon controlled triode; This triode combination comprises a positive-negative-positive triode and a NPN type triode, like a NPN type triode Q1 (being called for short NPN type triode Q1) and the second positive-negative-positive triode Q2 (being called for short positive-negative-positive triode Q2).The semiconductor control device is used for control and keeps on off state, and the emitter of positive-negative-positive triode Q2 links to each other with control end of switching tube in silicon controlled anode or the triode combination.
Referring to Fig. 3, triode combination and silicon controlled equivalence replacement schematic diagram have been shown.The pairing device of label among Fig. 3 (a) is a controllable silicon; Controllable silicon is formed along regarding as by two triodes after direction shown in the dotted line is cut open,, obtained two triodes after the conversion, shown in the part of label (c) referring to label (b) institute counterpart.
The emitter of positive-negative-positive triode Q2 is equivalent to the silicon controlled anode in the triode combination; The base stage of positive-negative-positive triode Q2 links with the collector electrode of NPN type triode Q1; The base-link of positive-negative-positive triode Q2 collector electrode and NPN type triode Q1 also is equivalent to the silicon controlled control utmost point, and the emitter of NPN type triode Q1 is equivalent to the silicon controlled negative electrode.
Adopt in the equivalents of triode combination at Fig. 2, utilize triode Q1 and Q2 to make up and keep on off state.Triode Q2 is a positive-negative-positive triode; Triode Q1 is a NPN type triode; Triode Q2 emitter (E) links to each other with Q4 grid (G); The base stage of triode Q2 (B) links to each other with the collector electrode (C) of triode Q1, and the collector electrode of triode Q2 (C) links to each other with the base stage (B) of triode Q1, and the emitter of triode Q1 (E) receives ground through the 3rd resistance R 3 (being called for short resistance R 3).The base stage of triode Q1 is received ground through resistance R 4, and triode Q1 base stage connects second capacitor C 2 (being called for short capacitor C 2) positive pole, C2 minus earth.
Can also shunt capacitance C3 at capacitor C 2 two ends, so that circuit is further adjusted, as carry out filtering etc., this capacitor C 3 not necessarily can be omitted.
Trigger button
Trigger button is used to trigger conducting and the dual operation of shutoff between importation and the output.Trigger button can be upspring after receiving external force and being pressed automatically.
Except above-mentioned three Primary Components, also be provided with other devices and annexation thereof in this switching circuit, with the successful realization that guarantees that switching circuit is opened or broken off, for example:
First capacitor C 1 (being called for short capacitor C 1) is parallelly connected with the 7th resistance R 7 (being called for short resistance R 7), and capacitor C 1 positive pole links together with the grid (G) of switching tube Q4 and the emitter (E) of positive-negative-positive triode Q2, and capacitor C 1 negative pole links to each other with the 2nd end of trigger button S1.The 1st termination the 8th resistance R 8 of trigger button S1 (be called for short resistance R a 8) end, and link to each other with the base stage of NPN type triode Q1 through the other end of resistance R 8.Simultaneously, this end (i.e. the 1st end) of linking to each other with resistance R 8 of trigger button S1 also links to each other with the collector electrode (C) of the 3rd NPN type triode Q3 (being called for short NPN type triode Q3).The emitter (E) of NPN type triode Q3 is ground connection directly, and the base stage (B) of NPN type triode Q3 connects the positive pole of capacitor C 4, the minus earth of capacitor C 4.Simultaneously; The base stage (B) of NPN type triode Q3 is also through moving the output of this switching circuit, the i.e. drain electrode of switching tube Q4 (D), the device that diode D2 discharges as acceleration on the 5th resistance R 5 (being called for short resistance R 5); Parallelly connected with resistance R 5; Its anode is connected to capacitor C 4 positive poles, and negative electrode is connected to output, and diode D2 looks the debugging situation and also can omit.
Above-mentioned when describing annexation; In order to make annexation clearer,, utilize the 1st end of trigger button and the 2nd end to describe the annexation between trigger button and other devices in conjunction with the mark among Fig. 2; Be appreciated that; Can indeterminate differentiation the 1st end and the 2nd end for trigger button, only need to make to form current path between the related elements or open circuit to get final product through the pressing or upspringing of trigger button.
Referring to Fig. 2, comprise the combination of three groups of resistance and electric capacity in the switching circuit of this circuit structure, specific as follows:
Combination 1: resistance and capacitor element combination 1 (capacitor C 1, resistance R 7); Be connected between the 2nd end of switch controlled end grid (G) and trigger button after resistance R 7 and capacitor C 1 parallel connection; Isolate and trigger the influence of button,, prevent long by misoperation through the operation that discharges and recharges to its capacitor C 1 to power supply; Create current channel, guarantee the reliable operation of switching circuit.
Combination 2: resistance and capacitor element combination 2 (capacitor C 2, resistance R 4); The 4th resistance R 4 (being called for short resistance R 4) and capacitor C 2 parallel connections; Be connected on then between the silicon controlled control utmost point and the ground, perhaps be connected between the base stage and ground that is used for alternative silicon controlled triode combination NPN type triode Q1.Through its operation that discharges and recharges to this capacitor C 2, be used for the by-pass cock machine time, prevent that external disturbance from causing the start misoperation, guarantee the reliable operation of switching circuit.
Combination 3: resistance and capacitor element combination 3 (capacitor C 4, resistance R 5); The 4th capacitor C 4 (being called for short capacitor C 4) is connected between the base stage and ground of NPN type triode Q3; And capacitor C 4 positive poles are received output through resistance R 5, and wherein NPN type triode Q3 is used for the connection of control input end and output or turn-offs.Through charging operations to this capacitor element C4, be used to regulate NPN type triode Q3 conducting required time, guarantee the switching circuit reliable operation.
Describe below in conjunction with the working method of above-mentioned concrete device, specifically comprise following start operator scheme and turn-off operator scheme this switching circuit:
The start operator scheme
If the current off-state that is in of switching circuit; And when switching to opening according to the demand needs; Be switching circuit in the start operator scheme, realize the operation of actuating switch pipe input and output (being actuating switch circuit input end and output) through following operation:
At input and output under the situation of off-state; Press trigger button S1, because the existence of resistance and capacitor element combination 1 and resistance and capacitor element combination 2, resistance and capacitor element combination 1 are added to electric current in resistance and the capacitor element combination 2 fast; And then voltage is added to the silicon controlled control end or substitutes the base stage of NPN type triode Q1 in the combination of silicon controlled triode; Trigger the conducting of said controllable silicon or triode combination, open switching tube simultaneously by input and output conducting, power supply begins to power to the load; And because controllable silicon conducting this moment or triode are combined into mutual locking saturation conduction state; Switch controlled extremely continues to be in than electronegative potential, even trigger button S1 breaks off, and the unlocking condition that controllable silicon or triode combination can the maintained switch pipes; Switching tube still continues conducting, accomplishes the start operation.
Turn-off operator scheme
If the current opening that is in of switching circuit, and when switching to off-state according to the demand needs, promptly switching circuit is realized breaking off the operation of input and output through following operation in turn-offing operator scheme:
Under the situation of conducting state, the power supply of output makes NPN type triode Q3 be in the saturation conduction state at switching tube input and output.Press trigger button S1 this moment; Because the temporal properties of the electric capacity in above-mentioned resistance and the capacitor element combination 1 import to ground with switch controlled end electric current through trigger button S1 and NPN type triode Q3, the electric current that promptly flows through the semiconductor control device is by bypass; Turn-off thereby make controllable silicon or substitute the combination of silicon controlled triode; After trigger button S1 upspring automatically, switching tube input and output broke off, and switching circuit switches to off-state from opening.
The operation principle of the switching circuit that further the utility model embodiment three is provided below in conjunction with a concrete scene describes.
In the switching circuit of present embodiment, the input voltage VIN of choosing DC power supply (battery) is 5V, and the concrete numerical value of input voltage VIN can be adjusted as required.Referring to Fig. 4, be that example describes as the scene of semiconductor control device mainly in the present embodiment to adopt the triode combination.
If the initial condition of switching circuit is an off-state,, analyze the switch operation principle of the utility model circuit below in conjunction with Fig. 4:
The start operator scheme
In the starting stage of using, trigger button S1 is not pressed, and input voltage VIN is 5V; NPN type triode Q1 and positive-negative-positive triode Q2 are in cut-off state; Current potential equates between the grid G of switching tube Q4 and the source S, and switching tube Q4 is in off-state, output VOUT no-output.
When input and output during in off-state, entire circuit does not have current drain basically, and minimum quiescent current can arrive 1uA, can regard the self discharge of battery as.
As shown in Figure 4, under the initial condition, suppose that switching circuit is in off state, the current potential of several Key Points is following in the circuit at this moment:
A point: be cell voltage 5V.
B point: be cell voltage 5V, the source electrode of switching tube Q4 (S) and grid (G) equipotential.Not conducting of switching tube Q4, triode Q1 and Q2 also are cut-off state at this moment.
The C point: because trigger button S1 is an off-state, because of the existence of resistance R 7, this moment, capacitor C 1 voltage equated, was supply voltage 5V.
D point: because switching tube Q4 is an off-state, so this moment, the D point voltage was 0V.
The E point: because triode Q1 and Q2 end, this moment, the E point voltage was 0V.
F point: 0V.
G point: equate with output end voltage, be 0V.
As shown in Figure 4, in order to open switching circuit, make power supply output to the load of output from input, only need press trigger button S1, make on the 1st end and the 2nd end short circuit of trigger button S1, at this moment, the electric current on the capacitor C 1 is through the circuit shown in the path 1.Resistance R 7 is equivalent to an accessory power supply with capacitor C 1, after trigger button S1 presses, charges to capacitor C 2 through trigger button S1 and resistance R 8.
Because the existence of resistance R 7, before trigger button S1 pressed, capacitor C 1 voltage was supply voltage 5V, because the electric capacity voltage can not be suddenlyd change; S1 presses moment at trigger button, and capacitor C 1 voltage is constant, and the electric current that flows through trigger button S1 is I=5/R8, should change little by this B point voltage; Along with the discharge of capacitor C 1 and the charging of capacitor C 2, B point and C point voltage reduce gradually, and E point current potential raises gradually; At last, if do not consider the conducting situation of triode Q1 and Q2, Q3
The B point voltage is stabilized in: UB=5* (R7+R8+R4)/(R1+R7+R8+R4),
The C point voltage is stabilized in: Uc=5* (R8+R4)/(R1+R7+R8+R4).
E point current potential is after certain value; NPN type triode Q1 begins conducting; The conducting of NPN type triode Q1 causes the base stage of positive-negative-positive triode Q2 to be dragged down; So positive-negative-positive triode Q2 conducting, the conducting of positive-negative-positive triode Q2 can be added to voltage on the base stage (B) of NPN type triode Q1 through its collector electrode (C) again,, triode combination Q1 and Q2 decide the saturation conduction state so getting into interlocking; B point electric current is pressed shown in the passage 2 and is arrived ground through positive-negative-positive triode Q2 and NPN type triode Q1, resistance R 3; Even if this moment, trigger button S1 broke off, do not have power supply to come to supply with NPN type triode Q1 base stage on the current path 1, but NPN type triode Q1 and positive-negative-positive triode Q2 still are in the saturation conduction state.Because the saturation conduction of NPN type triode Q1 and positive-negative-positive triode Q2; The appearance of current channel 2, the B point voltage drops to below the 1V, so the source electrode of switching tube Q4 (S) voltage is higher than grid (G); Switching tube Q4 conducting; Supply voltage is added in the load of output from input, and switching circuit switches to opening from off-state, and start is accomplished.
In switching tube Q4 turn on process, switching tube Q4 is as the switch of current path, and trigger button S1 is used for the conducting of trigger switch pipe Q4, and triode combination Q1, Q2 are used for keeping the conducting state of Q4.
Resistance R 3 is used for current limliting, and can improve the conducting voltage of NPN type triode Q1, prevents the misoperation when NPN type triode Q1 is disturbed.
Resistance R 4 is used for to stable initial condition of NPN type triode Q1 base stage (switching circuit is in the state of off-state NPN type triode Q1 base stage); Prevent triode Q1 misoperation; And resistance R 4 provides a discharge circuit for capacitor C 2; The resistance selection of R4 needs the satisfied E point that lets, and promptly the pressure drop on the resistance R 4 is greater than the required voltage request of Q1 conducting.
The size of capacitor C 2 appearance values can be controlled starting up speed, and the big more starting up speed of appearance value is slow more, and capacitor C 2 begins to be recharged when trigger button S1 presses, up to the enough relief triodes of voltage Q1 conducting.It can also prevent the interference of E point quilt and cause misoperation that ESD is had very big effect as storage capacitor, require the appearance value of capacitor C 2 appearance values less than capacitor C 1.
Resistance R 8 as the charging path of capacitor C 2, helps capacitor C 2 chargings when trigger button S1 presses.After trigger button S1 broke off, Q3 provided collector voltage for NPN type triode, kept the conducting of Q3 and isolated the influence of Q3 to Q1 base stage (E point).
After start is accomplished; Output voltage gives capacitor C 4 chargings through resistance R 5, and triode Q3 gets into the saturation conduction state, and input voltage is loaded into the load of output through switching tube Q4; This moment, switching circuit was in the conducting stable state, and the voltage of each point is among Fig. 4 at this moment:
A point: be supply voltage 5V.
The B point: concrete numerical value is relevant with resistance R 3 sizes, for example, and can be for about 0.8V.
C point: the same with the B point voltage.
D point: be about supply voltage, receive the influence of selected switching tube Q4 conduction voltage drop.
The E point: concrete numerical value is relevant with resistance R 3 sizes, for example, and can be for about 0.8V.This moment, triode combination Q1 and Q2 were in interlocking saturation conduction state.
The F point: less than 0.1V, this moment, Q3 was in the saturation conduction state.
The G point: can be relevant with resistance R 5 sizes, for example, can be 0.6V.
Turn-off operator scheme
Under the switching circuit conducting normal operating conditions, because the existence of resistance R 5 and capacitor C 4, this moment, NPN type triode Q3 was the saturation conduction state, and when pressing trigger button S1 once more, promptly trigger button S1 receives when triggering.
The negative pole of capacitor C 1 is connected to the collector electrode (C) of NPN type triode Q3, can be known by the characteristic of electric capacity, and 1 moment of capacitor C is equivalent to short circuit; Shown in 5 figure, current path 1 is impedance path than current path 2, and the electric current that B is ordered flows on the ground through current path 1; The electric current that promptly flows through the semiconductor control device is by bypass; The electric current that flows through triode combination Q1 and Q2 reduces, and keeps the current vanishes of triode combination Q1 and Q2 conducting, and the interlocking conducting of triode combination Q1 and Q2 is broken; Can know that by the controllable silicon turn-off criterion current path 2 disappears.
From the above mentioned, in conducting and turn off process, switching tube Q4 is as the switch of current path, and trigger button S1 is used for conducting or the shutoff of trigger switch pipe Q4.
Because the appearance of low impedance current path 1, the electric current of current path 2 reduces, and is not enough to keep the conducting of triode combination Q1 and Q2; Triode Q1, Q2 end in succession; The conducting state of keeping before making it of Q1 and Q2 disappears, and after trigger button S1 broke off, B point current potential rose to supply voltage; No longer satisfy the unlocking condition of switching tube, switching circuit switches to off-state from opening.
The appearance value size of capacitor C 2 also can influence power-off operation, because the electric current that flows through capacitor C 1 is only maximum in trigger button S1 closed moment, this moment, current path 2 electric currents were minimum, and the electric current of current path 1 reduces gradually then, and the B point voltage raises gradually.Have in the time period in this stage, if E point current potential has been reduced to below the triode Q1 turn-on condition voltage, then Q1 and Q2 get into off-state.Yet if selected C2 appearance value is excessive, E point current potential descended slow; E point current potential also is on the Q1 turn-on condition voltage after the B point voltage is raised to certain value; So triode combination Q1 and Q2 get into mutual locking conducting state once more, circuit pathways 2 still exists, and causes the power-off operation failure.
NPN type triode Q3 will construct low-impedance current path 1 with capacitor C 1 in power-off operation; So the state of NPN type triode Q3 is also extremely important; Require the state of triode Q3 to be in the saturation conduction state, the appearance value of the resistance of resistance R 5, capacitor C 4, the base stage saturation current three of triode Q3 need a balance on numerical value is chosen, and the electric capacity bigger owing to the appearance value is more expensive in price; And volume is big, can select the little triode of base stage saturation current to reduce the appearance value of capacitor C 4.
Triode Q3 is chosen for NPN type triode in the present embodiment; Switching tube Q4 is chosen for PMOS pipe or positive-negative-positive triode; Be appreciated that; Those skilled in the art can choose the device of other types and realize triode Q3 and switching tube Q4 etc. under the technical conceive of the utility model, and revise the related circuit structure adaptively, to reach identical technique effect.
By above-mentioned visible, the utility model the foregoing description utilizes trigger button collocation semiconductor control device and switching tube, and a kind of novel switching circuit is provided, and can realize the reliable break-make of power supply.
The present technique scheme adopts trigger button; Thereby relatively mechanical limit switch has smaller volume and profile flexibly; Reduced the requirement of product, improved the flexibility of product design, operated easy more laborsaving the space; And the EMI problem of having avoided mechanical limit switch to cause in the moment that connected sum breaks off, the useful life of having improved product.
And the present technique scheme need not complicated control chip or MCU, the work of having avoided extra code to write; The device that adopts is the most common semiconductor device commonly used; Simple in structure, significantly reduced hardware cost and development cost, have higher feasibility;
Further, each device is insensitive to static in the switching circuit that the present technique scheme provides, and interference free performance is quite high; Dependable performance; In practice, this programme can access desirable ESD test result, and long by with the situation of pressing trigger button fast under also can realize not having misoperation.
The above is merely the preferred embodiment of the utility model; Not in order to restriction the utility model; All within the spirit and principle of the utility model, any modification of being made, be equal to replacement, improvement etc., all should be included within the scope of the utility model protection.
Claims (10)
1. switching circuit; It is characterized in that said switching circuit comprises trigger button, semiconductor control device and switching tube, wherein; The input of said switching tube is connected with DC power supply; Said control end of switching tube is connected with DC power supply through first resistance (R1), and said output end of switching tube is connected with load, and said trigger button, semiconductor control device are connected to said control end of switching tube;
Under switching circuit was in off-state, said trigger button received when triggering, said switching tube conducting, and said switching circuit switches to opening from off-state, and the conducting of said semiconductor control device;
The said opening of the semiconductor control device maintained switch circuit after the conducting;
Under switching circuit was in opening, said trigger button received when triggering, and said semiconductor control device turn-offs, and when said switching tube broke off, said switching circuit switched to off-state from opening.
2. switching circuit according to claim 1 is characterized in that,
Said semiconductor control device is a silicon controlled rectifier, perhaps,
Said semiconductor control device is the combination of two triodes, and the combination of said two triodes comprises a NPN type triode (Q1) and the second positive-negative-positive triode (Q2).
3. switching circuit according to claim 2; It is characterized in that; Also comprise the 4th resistance (R4); When said semiconductor control device was the triode combination, the base stage of the collector electrode of the said second positive-negative-positive triode (Q2) and a NPN type triode (Q1) was connected the back through said the 4th resistance (R4) ground connection.
4. switching circuit according to claim 2 is characterized in that, also comprises the 3rd resistance (R3), and when said semiconductor control device was the triode combination, the emitter of a said NPN type triode (Q1) was through said the 3rd resistance (R3) ground connection.
5. switching circuit according to claim 3; It is characterized in that; Also comprise second electric capacity (C2); Said second electric capacity (C2) is connected in parallel on said the 4th resistance (R4) two ends, and the positive pole of said second electric capacity (C2) links to each other the minus earth of said second electric capacity (C2) with the base stage of a said NPN type triode (Q1).
6. switching circuit according to claim 5; It is characterized in that; Also comprise first electric capacity (C1) and the 7th resistance (R7), said first electric capacity (C1) and the 7th resistance (R7) are connected in parallel between said trigger button and the said control end of switching tube, wherein; The positive pole of said first electric capacity (C1) links to each other with said control end, and the negative pole of said first electric capacity (C1) links to each other with said trigger button.
7. switching circuit according to claim 6 is characterized in that,
The appearance value of said first electric capacity (C1) is greater than the appearance value of said second electric capacity (C2).
8. switching circuit according to claim 2; It is characterized in that; Also comprise the 4th electric capacity (C4) and the 5th resistance (R5); One end of said the 5th resistance (R5) is connected to said output end of switching tube, and the other end of said the 5th resistance (R5) is connected to the positive pole of said the 4th electric capacity (C4), the minus earth of said the 4th electric capacity (C4).
9. switching circuit according to claim 8; It is characterized in that; Also comprise the 3rd NPN type triode (Q3); The collector electrode of said the 3rd NPN type triode (Q3) is connected with said trigger button, the grounded emitter of said the 3rd NPN type triode (Q3), and the base stage of said the 3rd NPN type triode (Q3) is through said the 4th electric capacity (C4) ground connection.
10. switching circuit according to claim 2; It is characterized in that; Also comprise the 8th resistance (R8), when said semiconductor control device was the combination of two triodes, said trigger button was connected through the base stage of said the 8th resistance (R8) with a said NPN type triode (Q1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204059627U CN202268861U (en) | 2011-10-21 | 2011-10-21 | Switching circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204059627U CN202268861U (en) | 2011-10-21 | 2011-10-21 | Switching circuit |
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| Publication Number | Publication Date |
|---|---|
| CN202268861U true CN202268861U (en) | 2012-06-06 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011204059627U Expired - Lifetime CN202268861U (en) | 2011-10-21 | 2011-10-21 | Switching circuit |
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| CN (1) | CN202268861U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103066978A (en) * | 2011-10-21 | 2013-04-24 | 歌尔声学股份有限公司 | Switching circuit |
| CN104483585A (en) * | 2014-12-31 | 2015-04-01 | 工业和信息化部电子第五研究所 | Automatic transmission line pulse testing system |
-
2011
- 2011-10-21 CN CN2011204059627U patent/CN202268861U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103066978A (en) * | 2011-10-21 | 2013-04-24 | 歌尔声学股份有限公司 | Switching circuit |
| CN103066978B (en) * | 2011-10-21 | 2016-01-20 | 歌尔声学股份有限公司 | A kind of switching circuit |
| CN104483585A (en) * | 2014-12-31 | 2015-04-01 | 工业和信息化部电子第五研究所 | Automatic transmission line pulse testing system |
| CN104483585B (en) * | 2014-12-31 | 2017-06-13 | 工业和信息化部电子第五研究所 | Transfermatic pulse test system |
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Assignee: Weifang Goertek Electronics Co., Ltd. Assignor: Goertek Inc. Contract record no.: 2013370000060 Denomination of utility model: Switching circuit, filtering method and system thereof Granted publication date: 20120606 License type: Exclusive License Record date: 20130326 |
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Address after: 261031 Dongfang Road, Weifang high tech Industrial Development Zone, Shandong, China, No. 268 Patentee after: Goertek Inc. Address before: 261031 Dongfang Road, Weifang high tech Industrial Development Zone, Shandong, China, No. 268 Patentee before: Goertek Inc. |
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