CN102315633B - Electrostatic protection circuit - Google Patents
Electrostatic protection circuit Download PDFInfo
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- CN102315633B CN102315633B CN201010226292.2A CN201010226292A CN102315633B CN 102315633 B CN102315633 B CN 102315633B CN 201010226292 A CN201010226292 A CN 201010226292A CN 102315633 B CN102315633 B CN 102315633B
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Abstract
The invention discloses an electrostatic protection circuit. The electrostatic protection circuit comprises a sub-voltage generating circuit, a judgment circuit and a switch circuit, wherein the sub-voltage generating circuit outputs a first voltage and a second voltage; the judgment circuit is coupled with the sub-voltage generating circuit and is used for receiving the first voltage and the second voltage and determining the voltage level of an output voltage according to the first voltage and the second voltage; the switch circuit is coupled with the judgment circuit and is used for judging whether the switch circuit is switched on or not according to the output voltage; and the transient voltage of the first voltage is different from the transient voltage of the second voltage.
Description
Technical field
The present invention relates to a kind of electronic circuit, espespecially a kind of electrostatic discharge protection circuit.
Background technology
Static discharge (Electrostatic Discharge, ESD) be to cause most of electronic components to be subject to the excessively electrically principal element of stress rupture, this destruction can cause electronic component to form a kind of permanent breaking-up, thereby affects the normal operation of electronic component.Generally speaking, can utilize an electrostatic discharge protection circuit to avoid the destruction of static discharge.
Traditional electrostatic discharge protection circuit is whether utilize speed that voltage rises to differentiate be static discharge, if yet it is too fast that starting up speed occurs, cause voltage to rise too rapid, it is normal boot-strap that traditional electrostatic discharge protection circuit cannot be told, cause electrostatic discharge protection circuit by error starting, make a unexpected electric current pass through electrostatic discharge protection circuit.
Summary of the invention
One of object of the present invention is to provide a kind of electrostatic discharge protection circuit, and it can avoid unexpected misoperation to occur.
One of object of the present invention is to provide a kind of electrostatic discharge protection circuit, and it can be avoided because start behavior is by error starting.
Of the present inventionly one of solid be to provide a kind of electrostatic discharge protection circuit, it can avoid rising by error starting at a high speed because of power source charges transient voltage.
One of object of the present invention provides a kind of electrostatic discharge protection circuit, can avoid because voltage excessive velocities is by error starting.
One embodiment of the invention provide a kind of electrostatic discharge protection circuit, have a first node, and in order to receive an input voltage, electrostatic discharge protection circuit comprises a dividing potential drop and produces circuit, a decision circuitry and a switching circuit.Dividing potential drop produces circuit output one first voltage one second voltage, and wherein, the first voltage second voltage is in order to reflect the variation situation of the voltage of input voltage, and wherein, the voltage of the first voltage is not identical with the voltage of second voltage.Decision circuitry couples dividing potential drop and produces circuit, receives the first voltage second voltage, and according to the first voltage second voltage, determines the voltage quasi position of an output voltage.Switching circuit couples decision circuitry, and according to the level determine switch circuit turn-on state of output voltage.
Electrostatic discharge protection circuit of the present invention can be told static discharge or normal working voltage in the quick situation of voltage, thereby avoids electrostatic discharge protection circuit misoperation.
Accompanying drawing explanation
Fig. 1 is the embodiment schematic diagram that electrostatic discharge protection circuit of the present invention is shown.
Fig. 2 A be one embodiment of the invention is shown electrostatic discharge protection circuit when circuit just starts, the voltage voltage analogous diagram in rapid situation that rises
Fig. 2 B is the current simulations figure illustrating corresponding to Fig. 2 A.
Fig. 3 A illustrates the electrostatic discharge protection circuit of one embodiment of the invention at electrostatic potential V
eSDvoltage analogous diagram in situation about occurring.
Fig. 3 B is the current simulations figure illustrating corresponding to Fig. 3 A.
Fig. 4 is the embodiment schematic diagram that electrostatic discharge protection circuit of the present invention is shown.
Fig. 5 is the embodiment schematic diagram that electrostatic discharge protection circuit of the present invention is shown.
Fig. 6 is the embodiment schematic diagram that electrostatic discharge protection circuit of the present invention is shown.
Fig. 7 A be one embodiment of the invention is shown electrostatic discharge protection circuit when circuit just starts, the voltage voltage analogous diagram in rapid situation that rises
Fig. 7 B is the current simulations figure illustrating corresponding to Fig. 7 A.
Fig. 8 A is the electrostatic discharge protection circuit that one embodiment of the invention is shown, at electrostatic potential V
eSDvoltage analogous diagram in situation about occurring.
Fig. 8 B is the current simulations figure illustrating corresponding to Fig. 8 A.
[main element symbol description]
100,200,300,400,500,600 electrostatic discharge protection circuits
101,401 dividing potential drops produce circuit
101a, 101b, 201a, 201b, 301a, 301b, 401a, 401b, 401c resistance
101c, 401d electric capacity
102,402 decision circuitry
102a, 102b, 402a, 402b switch
103,403 switching circuits
N1, N2, N3, Nj node
Embodiment
Fig. 1 is the embodiment schematic diagram that electrostatic discharge protection circuit of the present invention is shown.As shown in Figure 1, electrostatic discharge protection circuit 100 comprises dividing potential drop generation circuit 101, a decision circuitry 102 and a switching circuit 103.Electrostatic discharge protection circuit 100 has a node N1, is for receiving an input voltage vin, and according to the voltage swing of input voltage vin and input voltage vin the rate of climb during a transient state, whether determine conducting (On) switching circuit 103.When switching circuit 103 is switched on, electric current is released into earth potential G through switching circuit 103.
In one embodiment, as shown in Figure 1, dividing potential drop produces circuit 101 can comprise resistance 101a, 101b and electric capacity 101c.One end of resistance 101a couples node N1, other end series resistance 101b.Decision circuitry 102 is coupled to the node N2 between resistance 101a and 101b, and electric capacity 101c couples resistance 101b, and decision circuitry 102 is coupled to the node N3 between resistance 101b and electric capacity 101c, and node N2 and N3 difference output voltage V p and Vn.
Note that in an embodiment, if resistance 101a with 101b for connecting, the voltage swing of its voltage Vp and Vn is to determine according to the resistance value size of resistance 101a, 101b and electric capacity 101c.Another embodiment, the number of resistance and electric capacity and coupling mode (for example series-parallel system) all can be determined by designer, are not restricted to this; In addition, resistance and/or electric capacity also can be implemented by the current existing or future various semiconductor elements that develop, for example transistor ... etc.
One embodiment, as shown in Figure 1, decision circuitry 102 can comprise switch 102a and 102b.Node N2, the other end that one end of switch 102a couples dividing potential drop generation circuit 101 couple input voltage vin, and the other end couples switch 102b and forms a node Nj; One end of switch 102b couples that node N3, the other end that dividing potential drop produces circuit 101 couple node Nj and the other end couples an earth potential G.
Switch 102a and 102b be receiver voltage Vp and Vn respectively, according to voltage Vp and Vn, determines an output voltage V 3, therefore decision circuitry 102 can change because of the voltage swing of voltage Vp and Vn, the voltage quasi position of output voltage V 3 is also changed.
In one embodiment, switch 102a can be a P-type mos field-effect transistor and realizes, and switch 102b is that a N-type mos field effect transistor is realized.Certainly, in another embodiment, switch 102a, 102b are not limited to this, and it can be implemented by other current existing or future semiconductor element developing.
As the example of Fig. 1, the source electrode of switch 102a couples node N1 and receives input voltage vin, and the grid of switch 102a flows through the size of switch 102a according to size decision conducting state, nonconducting state or the electric current of voltage Vp.In addition, conducting voltage V1 is the voltage difference (being V1=Vin-Vp) of input voltage vin and voltage Vp, and conducting voltage V2 is the voltage difference (being V2=Vn-0) of voltage Vn and earth potential G.Accordingly, the drain electrode of switch 102b couples the drain electrode of switch 102a, and the source electrode of switch 102b couples earth potential G, and the grid of switch 102b determines that according to the size of voltage Vn conducting state, nonconducting state or electric current flow through the size of switch 102b.Therefore, the conducting state of control switch 102a and 102b, can reach output voltage V 3 sizes of adjusting decision circuitry 102 thus.
One embodiment, switching circuit 103 couples decision circuitry 102 and input voltage vin, and according to output voltage V 3 decide switching circuit 103 conducting state, nonconducting state or electric current flow through the size of switching circuit 103, and then can reach the effect of control switch circuit 103 action.For example, when switching circuit 103 conducting, electric current can be released into earth potential G via switching circuit 103.In the present embodiment, switching circuit 103 can be a N-type mos field effect transistor and realizes, but the present invention should be as limit.Another embodiment, also can be implemented by the current existing or future semiconductor element developing.
For make input voltage vin that electrostatic discharge protection circuit 100 can decision node N1 receives for the operating voltage Vdd starting be fast still electrostatic potential V
eSDtherefore, please also refer to Fig. 2 A, in the present invention one implements, when input voltage vin is the operating voltage Vdd starting fast, input voltage vin is Tr between the quick starting period, and meaning is that input voltage vin is during fast rise, generally speaking Tr is less than 10 μ s, and the relational expression of voltage Vp, resistance 101a and 101b meets in fact following equation:
Wherein, Z1 and Z2 represent respectively the equivalent impedance of resistance 101a and 101b, the operating voltage that Vdd is input voltage vin, V
thpfor the critical voltage (threshold voltage) of switch 102a, V1 is the conducting voltage of switch 102a; Special instruction, at input voltage vin Tr between the quick starting period, because the input voltage vin rate of climb is very fast, the voltage difference that makes electric capacity 101c can instantaneous variation, and one end of electric capacity 101c couples earth potential G, and therefore, voltage Vn levels off to zero.It is noted that, between the quick starting period, after Tr, the effect of electric capacity 101c starts to occur, and therefore in 2A figure, can find, voltage Vp and voltage Vn start slowly to rise.
And please also refer to Fig. 2 A, Fig. 2 A illustrates electrostatic discharge protection circuit 100 of the present invention when just starting (power on), voltage analogous diagram in input voltage vin fast rise situation, can be understood input voltage vin, voltage Vp and voltage Vn three's relation by Fig. 2 A.
Dividing potential drop produces circuit 101 and receives input voltage vin, and export a voltage Vp and a voltage Vn according to input voltage vin, wherein, for example, as input voltage vin Tr (: circuit just starts) between the quick starting period, resistance value Z1 and Z2 via design resistance 101a and resistance 101b, the transient voltage of voltage Vp and the formed conducting voltage V1 of operating voltage Vdd, make switch 102a in nonconducting state; By Fig. 2 A, can be understood, Tt during a transient state, from circuit, just start (t=0) to (comprising Tr between the quick starting period) during stable state, the transient voltage of voltage Vp and the formed conducting voltage V1 of operating voltage Vdd, still make switch 102a in nonconducting state.Therefore, by above-mentioned, can be understood, the electrostatic discharge protection circuit 100 of the present embodiment, in the zooming situation of input voltage vin, when input voltage vin is less than a default value, it is nonconducting state that the transient voltage of voltage Vp makes switch 102a, illustrate, in an enforcement, operating voltage is 3.3V, therefore default value can be set as 3.3V (maybe can be set as a little more than 3.3V), and when input voltage vin is less than or equal to 3.3V, the transient voltage of the voltage Vp that dividing potential drop generation circuit 101 is exported makes switch 102a in nonconducting state.
In like manner, in the zooming situation of input voltage vin, when input voltage vin is greater than another default value, it is conducting state that the transient voltage of voltage Vp makes switch 102a, illustrates, in an enforcement, operating voltage is 3.3V, therefore default value can be set as 5V, and when input voltage vin is greater than 5V, the transient voltage of the voltage Vp that dividing potential drop generation circuit 101 is exported makes switch 102a in conducting state.
In addition, Tt during transient state, the size of the transient voltage of voltage Vp and voltage Vn is unequal.For switching circuit 103 Tt during transient state is not switched on, between voltage Vp of the present invention, voltage Vn and operating voltage Vdd, be to there is a preset relation, the formed conducting voltage V1 of Vp and Vdd, makes switch 102a in nonconducting state.
Must note, when voltage Vin is operating voltage Vdd and without V
eSDduring interference, the input voltage vin of electrostatic discharge protection circuit 100 in Tr, can be learnt by aforementioned formula (2) between the quick starting period,
operating voltage Vdd is because of impedance Z 1 dividing potential drop with Z2, and makes the magnitude of voltage of conducting voltage V1 be less than the critical voltage Vthp of switch 102a; Certainly, due to the impact of electric capacity 101c, fast between the starting period after Tt to electrostatic discharge protection circuit 100 before stable state, voltage Vp rises gradually, so the magnitude of voltage of conducting voltage V1 is still less than the critical voltage Vthp of switch 102a.Therefore, switch 102a will be in non-conduction (Off) state, can avoid approaching when the input voltage vin rate of climb speed of static discharge, causes switch 102a conducting and allows switching circuit 103 error startings.Magnitude of voltage as for the conducting voltage V2 of node N3, because the zooming relation of input voltage vin (Vdd) causes electric capacity 101c stored charge speed slower, make the voltage quasi position of conducting voltage V2 still in low-voltage (leveling off to 0), switch 102b is in non-conduction (Off) state.Because switch 102a and 102b are all in non-conduction (Off) state, so time node Nj be suspension joint (floating), output voltage V 3 is in unknown state, please refer to Fig. 2 B, above-mentioned output voltage V 3 is in unknown state, may cause switching circuit 103 conductings, electrostatic discharge protection circuit 100 may produce a unexpected electric current by switching circuit 103, but due to voltage Vn (being conducting voltage V2), between the starting period, after Tr, can slowly rise fast, when voltage Vn is greater than the critical voltage Vthn of switch 102b, switch 102b is immediately in conducting (On) state, now output voltage V 3 is low-voltage level, to guarantee that switching circuit 103 is in nonconducting state, and more than can reaching 400mA than the unexpected current maxima of known electrostatic discharge protection circuit, the unexpected current maxima of the present embodiment is much smaller than 400mA, therefore unexpected electric current can decline to a great extent.And electrostatic discharge protection circuit 100 enters after stable state, by Fig. 2 A, can be understood, the voltage quasi position of voltage Vp, Vn equates with operating voltage Vdd, switching circuit 103 still maintains nonconducting state.
When input voltage vin is electrostatic potential V
eSDtime, and input voltage vin Tr during fast rise, electrostatic discharge protection circuit meets in fact following equation:
Wherein, V
eSDthe magnitude of voltage producing while being expressed as static discharge.
Please also refer to Fig. 3 A, Fig. 3 A illustrates electrostatic discharge protection circuit of the present invention, at electrostatic potential V
eSDbe introduced into the voltage analogous diagram in situation.Fig. 3 A can understand input voltage vin, voltage Vp and voltage Vn three's relation.
When the situation generation of static discharge, input voltage vin is electrostatic potential V
eSDtime, by aforementioned formula (3), can be learnt,
although electrostatic potential V
eSDstill by impedance Z 1 and Z2 dividing potential drop, but because electrostatic potential V
eSDmagnitude of voltage be generally much larger than operating voltage Vdd, even so through dividing potential drop, the magnitude of voltage of the conducting voltage V1 being caused by electrostatic potential VESD still can be greater than the critical voltage Vthp of switch 102a, therefore switch 102a will be in conducting (On) state, and switching circuit 103 is in conducting state, with release electrostatic voltage V
eSDthe electric current causing; Special instruction, at electrostatic potential V
eSDduring fast rise, after Tr, owing to still having, electric current is by electric capacity 101c slightly, and the voltage of electric capacity 101c can slightly rise, and in Fig. 3 A, can find, voltage Vp and voltage Vn still can slowly rise, and move closer to input voltage vin; In Fig. 3 A, the dated t2 time is the critical voltage Vthp that voltage Vp and the formed conducting voltage V1 of electrostatic potential are less than switch 102a, and now switching circuit 103 is in nonconducting state.
And the magnitude of voltage of the conducting voltage V2 of node N3, because of electrostatic potential V
eSDzooming relation, cause electric capacity 101c stored charge speed slower, make the voltage quasi position of conducting voltage V2 still in low-voltage (leveling off to 0), switch 102b is in non-conduction (Off) state, pay special attention to, in the present embodiment, the RC time constant that resistance 101a, 101b and electric capacity 101c form need be greater than the time of origin of static discharge, make switch 102b in the time of origin of static discharge, still in nonconducting state.
Refer again to Fig. 3 B, Fig. 3 B illustrates electrostatic discharge protection circuit 100 corresponding to the current simulations figure of Fig. 3 A.At conducting voltage V1, be greater than switch 102a critical voltage Vthp during, because switching circuit 103 is switched on, therefore produce a static discharge current (electric current as shown in Figure 3 B), it flows through switching circuit 103, make electric current be released into earth potential G via switching circuit 103, avoid circuit because electrostatic potential V
eSDbe subject to permanent damage.
At this, note that the A from Fig. 3, when electrostatic discharge protection circuit 100 is during in stable state, electrostatic potential V
eSD, voltage Vp and voltage Vn voltage quasi position can level off to equal.
Refer to Fig. 4, Fig. 4 is that the dividing potential drop that electrostatic discharge protection circuit of the present invention is shown produces circuit in the schematic diagram of an embodiment, as shown in Figure 4, electrostatic discharge protection circuit 200 is with the difference of electrostatic discharge protection circuit 100, resistance 201a, 201b are realized by P-type mos field-effect transistor respectively, the gate terminal of resistance 201a, 201b is coupled to respectively earth potential G, the equiva lent impedance of resistance 201a, 201b is Z1, Z2, disclose so far, all the other operating principles are identical with electrostatic discharge protection circuit 100, and its detailed operation of event does not separately repeat in this for the sake of clarity.
Refer to Fig. 5, Fig. 5 is that the dividing potential drop that electrostatic discharge protection circuit of the present invention is shown produces circuit in the schematic diagram of an embodiment, as shown in Figure 5, electrostatic discharge protection circuit 300 is with the difference of electrostatic discharge protection circuit 100, resistance 301a, 301b are realized by N-type mos field effect transistor respectively, the gate terminal of resistance 301a, 301b is coupled to respectively operating voltage Vdd, the equiva lent impedance of resistance 301a, 301b is Z1, Z2, disclose so far, all the other operating principles are identical with electrostatic discharge protection circuit 100, for the sake of clarity, therefore do not repeat separately at this.
Refer to Fig. 6, Fig. 6 is the embodiment schematic diagram that electrostatic discharge protection circuit of the present invention is shown, as shown in Figure 6, electrostatic discharge protection circuit 400 is with the difference of electrostatic discharge protection circuit 100, and dividing potential drop produces circuit 401 and comprises a resistance 401a, 401b, 401c and electric capacity 401d.
One end of resistance 401a is coupled to and couples node N1, other end series resistance 401b, and the two ends of resistance 401c are series resistance 401b and electric capacity 401d respectively.
And decision circuitry 402 couples the node N2 between resistance 401a and 401b, in addition, decision circuitry 402 also couples a node N3 between resistance 401b and 401c, and node N2 and N3 difference output voltage V p and Vn.
Note that the voltage swing of its voltage Vp and Vn is that the resistance value by resistance 401a, 401b, 401c and electric capacity 401d determines by dividing potential drop theorem respectively because resistance 401a, 401b, 401c three are series connection.
One embodiment, as shown in Figure 6, decision circuitry 402 can comprise switch 402a and 402b, and node N2, the other end that one end of switch 402a couples dividing potential drop generation circuit 401 couple input voltage vin, and the other end couples switch 402b and forms a node Nj; One end of switch 402b couples that node N3, the other end that dividing potential drop produces circuit 401 couple node Nj and the other end couples an earth potential G.
In one embodiment, switch 402a is that a P-type mos field-effect transistor is realized, and switch 402b is that a N-type mos field effect transistor is realized.Certainly, in another embodiment, switch 402a, 402b are not limited to this, and it can be implemented by other current existing or future semiconductor element developing.
As shown in Figure 6, the source electrode of switch 402a couples node N1 and receives input voltage vin, and the gate terminal of switch 402a flows through the size of switch 402a according to size decision conducting state, nonconducting state or the electric current of voltage Vp.
Accordingly, the drain electrode of switch 402b couples the drain electrode of switch 402a, and the source electrode of switch 402b couples earth potential G, and the grid of switch 402b determines that according to the size of voltage Vn conducting state, nonconducting state or electric current flow through the size of switch 402b.Therefore, the conducting state of control switch 402a and 402a thus, can reach the size of the output voltage V 3 of adjusting decision circuitry 402.
One embodiment, switching circuit 403 couples decision circuitry 402 and input voltage vin, and decide conducting state, nonconducting state or the electric current of switching circuit 403 to flow through the size of switching circuit 403 according to output voltage V 3, and then can reach the effect of control switch circuit 403 actions.For example, when switching circuit 403 conducting, electric current can be released into earth potential G via switching circuit 403.In the present embodiment, switching circuit 403 can be a N-type mos field effect transistor and realizes, but the present invention should be as limit.Another embodiment, also can be implemented by the current existing or future semiconductor element developing.
For the input voltage vin that electrostatic discharge protection circuit 400 can decision node N1 be received is the operating voltage Vdd for starting fast or is electrostatic potential V
eSDtherefore, please also refer to Fig. 7 A, in the present invention one implements, when input voltage vin is the operating voltage Vdd starting fast, input voltage vin is Tr between the quick starting period, and meaning is that input voltage vin is during fast rise, generally speaking Tr is less than 10 μ s, and the relational expression of voltage Vp, Vn, resistance 401a, 401b, 401c is as follows:
Wherein, Z1, Z2, Z3 represent respectively the equivalent impedance of resistance 401a, 401b and 401c, the operating voltage that Vdd is input voltage vin, V
thpfor the critical voltage (threshold voltage) of switch 402a, V
thncritical voltage for switch 402b, V1 is the conducting voltage of switch 402a, V2 is the conducting voltage of switch 402b, wherein, conducting voltage V1 is the voltage difference (being V1=Vin-Vp) of input voltage vin and voltage Vp, and conducting voltage V2 is the voltage difference (being V2=Vn-0) of voltage Vn and earth potential G.
What specify is, in input voltage vin, between the quick starting period during Tr, because the input voltage vin rate of climb is very fast, the voltage difference that makes electric capacity 401d can instantaneous variation, again because of voltage divider principle, therefore the voltage Vn that node N3 exports levels off to 1V in one embodiment.It is noted that, between the quick starting period, after Tr, the effect of electric capacity 401d starts to occur, and therefore in Fig. 7 A, can find, voltage Vp and voltage Vn start slowly to rise.
Please also refer to Fig. 7 A, Fig. 7 A illustrates electrostatic discharge protection circuit 400 of the present invention when just starting (power on), voltage analogous diagram in input voltage vin fast rise situation, Fig. 7 A can understand input voltage vin, voltage Vp and voltage Vn three's relation.
Dividing potential drop produces circuit 401 and receives input voltage vin, and export a voltage Vp and a voltage Vn according to input voltage vin, wherein, for example, as input voltage vin Tr (: when circuit just starts) between the quick starting period, via design resistance 401a, the corresponding resistance value Z1 of 401b, 401c, Z2, Z3, the transient voltage of voltage Vp and the formed conducting voltage V1 of operating voltage Vdd, make switch 402a in nonconducting state; By Fig. 7 A, can be understood, Tt during a transient state, from circuit, just start (t=0) to (comprise open fast during Tr) during stable state, the transient voltage of voltage Vp and the formed conducting voltage V1 of operating voltage Vdd, still make switch 402a in nonconducting state; In addition, Tt during transient state, the size of the transient voltage of voltage Vp and voltage Vn is unequal.For switching circuit 403 Tt during transient state is not switched on, the design condition of voltage Vp of the present invention and voltage Vn is to have a preset relation, and the formed conducting voltage V1 of Vp and Vdd, makes switch 402a in nonconducting state.
Must note, when voltage Vin is operating voltage Vdd and without electrostatic potential V
eSDduring interference, the input voltage vin of electrostatic discharge protection circuit 400 is Tr between the quick starting period, by aforementioned formula (7), can be learnt,
operating voltage Vdd is the dividing potential drop because of impedance Z 1, Z2, Z3, and makes the magnitude of voltage of conducting voltage V1 can be less than the critical voltage V of switch 402a
thp; Certainly, due to the impact of electric capacity 401d, fast between the starting period after Tt to electrostatic discharge protection circuit 400 before stable state, voltage Vp rises gradually, so the magnitude of voltage of conducting voltage V1 is still less than the critical voltage Vthp of switch 402a.Therefore, switch 402a will can avoid when the input voltage vin rate of climb approaches the speed of static discharge in non-conduction (Off) state, causes switch 402a to be switched on, and allows switching circuit 403 by error starting.
As for the magnitude of voltage of the conducting voltage V2 of node N3, by aforementioned formula (8),
the magnitude of voltage that can learn conducting voltage V2 is the critical voltage V that is designed to be greater than switch 402b
thn, in the present embodiment, switch 402b is in conducting state, in other words, no matter at Tt during transient state or electrostatic discharge protection circuit 400 after stable state, switch 402b is all in conducting state.Therefore the output voltage V 3 of node Nj is pulled to low-voltage, can guarantee that switching circuit 403 Tr between the quick starting period is in nonconducting state, therefore switching circuit 403 can be by error starting, avoid aforesaid embodiment, because switch 102a and 102b are all in non-conduction (Off) state, making node Nj is suspension joint (floating) state, and output voltage V 3 is in unknown state.
Please refer to Fig. 7 B, Fig. 7 B illustrates electrostatic discharge protection circuit corresponding to the current simulations figure of Fig. 7 A, when voltage rises too rapidly (when circuit just starts), it is unexpected that electric current level off to 0 (electric current as shown in Figure 7 B), more than may reaching 400mA than the unexpected current maxima of known electrostatic discharge protection circuit, the about 1.4mA of unexpected current maxima of the present embodiment, therefore unexpected electric current declines to a great extent significantly, the risk that reduces short circuit occurs.
And electrostatic discharge protection circuit 400 enters after stable state, by Fig. 7 A, can be understood, the voltage quasi position of voltage Vp, Vn equates with operating voltage Vdd, switch 402a is still in nonconducting state, now switch 402b is still in conducting state, 3 of output voltage V are still low-voltage level, and now switching circuit 403 is not conducting, and electrostatic discharge protection circuit 100 reverts to not starting state.
When input voltage vin is electrostatic potential V
eSDtime, and input voltage vin Tr during fast rise, electrostatic discharge protection circuit meets in fact following equation:
V wherein
eSDthe magnitude of voltage producing while being expressed as static discharge.
At this, note that by formula (8), (10) and can understand, no matter, at the state of normal operating conditions or static discharge, the magnitude of voltage of conducting voltage V2 is the critical voltage V that is designed to be greater than switch 402b
thn.
Please also refer to Fig. 8 A, Fig. 8 A illustrates electrostatic discharge protection circuit of the present invention, at electrostatic potential V
eSDbe introduced into the voltage analogous diagram in situation.Fig. 8 A can understand input voltage vin, voltage Vp and voltage Vn three's relation.
When the situation generation of static discharge, input voltage vin is electrostatic potential V
eSDtime, by aforementioned formula (9), can be learnt,
although electrostatic potential V
eSDstill by impedance Z 1, Z2, Z3 dividing potential drop, but because electrostatic potential V
eSDmagnitude of voltage be generally much larger than operating voltage Vdd, even so through dividing potential drop, the magnitude of voltage of the conducting voltage V1 being caused by electrostatic potential VESD can be greater than the critical voltage Vthp of switch 402a, therefore switch 402a will be in conducting (On) state, and switching circuit 403 is in conducting state, with release electrostatic voltage V
eSDthe electric current causing; Special instruction, at electrostatic potential V
eSDduring fast rise, after Tr, owing to still having, electric current is by electric capacity 401d slightly, and the voltage of electric capacity 401d can slightly rise, and in 8A figure, can find, voltage Vp and voltage Vn still can slowly rise, and move closer to input voltage vin; In Fig. 8 A, the dated t2 time is the critical voltage Vthp that voltage Vp and the formed conducting voltage V1 of electrostatic potential start to be less than switch 402a, and now switching circuit 403 is in nonconducting state.
And the magnitude of voltage of the conducting voltage V2 of node N3 can be learnt by aforementioned formula (10), the magnitude of voltage of conducting voltage V2 can be greater than the critical voltage V of switch 402b
thntherefore switch 402b will be in conducting state.
Refer again to Fig. 8 B, Fig. 8 B illustrates electrostatic discharge protection circuit 400 corresponding to the current-mode graphoid of Fig. 8 A.At conducting voltage V1, be greater than switch 402a critical voltage Vthp during, because switching circuit 403 is switched on, therefore produce an electric current (electric current as shown in Figure 8 B), electric current is to flow through switching circuit 403, make electric current be released into earth potential G via switching circuit 403, avoid circuit because electrostatic potential V
eSDbe subject to permanent damage.
In addition, the corresponding time constant of resistance 401a, 401b, 401c and electric capacity 401d is greater than the static discharge time, and in other words, the RC time constant being comprised of resistance 401a, 401b, 401c and electric capacity 401d need be greater than the time of origin of static discharge.
At this, note that the A from Fig. 8, when electrostatic discharge protection circuit 400 is during in stable state, electrostatic potential V
eSD, voltage Vp and voltage Vn voltage quasi position can level off to equal.
In this enforcement, when static discharge situation occurs, switch 402a and 402b are switched on simultaneously, and output voltage V 3 is that the conduction impedance value by switch 402a and 402b is determined, in other words, can suitably design the conduction impedance value of switch 402a and 402b, make the magnitude of voltage of output voltage V 3 be enough to starting switch circuit 403.Because the equivalent impedance of switching circuit 403 is less than the equivalent impedance of decision circuitry 402, therefore, what static discharge produced will be released into earth potential G by switching circuit 403 compared with large electric current, to avoid electronic component to be damaged.
In sum, electrostatic discharge protection circuit of the present invention can rise in quick situation at voltage, tells static discharge or normal working voltage, thereby avoids the misoperation of electrostatic discharge protection circuit.
Claims (17)
1. an electrostatic discharge protection circuit, has a first node, and in order to receive an input voltage, described electrostatic discharge protection circuit comprises:
One dividing potential drop produces circuit, couple described first node, described dividing potential drop produces circuit output one first voltage and a second voltage, wherein, when described input voltage is during a transient state, the transient voltage of described the first voltage is not identical with the transient voltage of described second voltage;
One decision circuitry, couples described dividing potential drop and produces circuit, receives described the first voltage and described second voltage, and according to described the first voltage, described second voltage, determines the voltage quasi position of an output voltage; And
One switching circuit, couples described decision circuitry, and determines described switching circuit conducting state according to the voltage quasi position of described output voltage,
Wherein said decision circuitry comprises:
One first switch, couples a Section Point of exporting described the first voltage in described bleeder circuit, according to described the first voltage, determines the whether conducting of described the first switch; And
One second switch, one end couples one the 3rd node of exporting described second voltage in described bleeder circuit, and the other end couples described the first switch, and described second switch determines the whether conducting of described second switch according to described second voltage;
Wherein, whether the voltage quasi position of described output voltage decides according to described the first switch and described second switch conducting.
2. electrostatic discharge protection circuit according to claim 1, wherein said dividing potential drop produces circuit and comprises:
One first resistance, one end couples described first node;
One second resistance, the other end of described the first resistance of connecting, described decision circuitry is coupled to the described Section Point between described the second resistance and described the first resistance; And
One electric capacity, one end is coupled to described the second resistance and other end ground connection, and described decision circuitry is coupled to described the 3rd node between described the second resistance and described electric capacity.
3. electrostatic discharge protection circuit according to claim 2, wherein, during described transient state, be between a rising stage of described input voltage, the transient voltage of described the first voltage and the transient voltage of described second voltage are determined by described input voltage, described the first resistance and described the second resistance.
4. electrostatic discharge protection circuit according to claim 1, is between a rising stage of described input voltage during wherein said transient state.
5. electrostatic discharge protection circuit according to claim 4, wherein, when described input voltage is an operating voltage, the transient voltage of described the first voltage makes described the first switch keep nonconducting state.
6. electrostatic discharge protection circuit according to claim 4, wherein, when described input voltage is an electrostatic potential, the transient voltage of described the first voltage makes described the first switch keep conducting state.
7. electrostatic discharge protection circuit according to claim 1, wherein, when described input voltage is less than or equal to a default value, it is nonconducting state that the transient voltage of described the first voltage makes described the first switch.
8. electrostatic discharge protection circuit according to claim 1, wherein, when described input voltage is greater than a default value, it is conducting state that the transient voltage of described the first voltage makes described the first switch.
9. electrostatic discharge protection circuit according to claim 2, wherein said the first resistance has one first resistance value Z1, described the second resistance and has one second resistance value Z2, described the first switch has a critical voltage V
thp; When described input voltage is an operating voltage Vdd, the transient voltage of described the first voltage Vp meets in fact following equation:
10. electrostatic discharge protection circuit according to claim 9, wherein when described input voltage is an electrostatic potential V
eSDtime, the transient voltage of described the first voltage Vp meets in fact following equation:
11. electrostatic discharge protection circuits according to claim 2, wherein said the first resistance, described the second resistance and the corresponding time constant of described electric capacity are greater than the static discharge time.
12. electrostatic discharge protection circuits according to claim 1, wherein said dividing potential drop produces circuit and comprises:
One first resistance, one end is coupled to described first node;
One second resistance, the connect other end of described the first resistance of one end, described decision circuitry is coupled to the described Section Point between described the second resistance and described the first resistance;
One the 3rd resistance, the connect other end of described the second resistance of one end, described decision circuitry is coupled to described the 3rd node between described the second resistance and described the 3rd resistance; And
One electric capacity, its one end is coupled to the other end of described the 3rd resistance, and the other end of described electric capacity is coupled to an earth potential.
13. electrostatic discharge protection circuits according to claim 12, wherein, when described input voltage is between a rising stage, the transient voltage of described the first voltage and the transient voltage of described second voltage are determined by described input voltage, described the first resistance, described the second resistance and described the 3rd resistance.
14. electrostatic discharge protection circuits according to claim 12, wherein, when described input voltage is between a rising stage, the transient voltage of described second voltage makes described second switch keep conducting state.
15. electrostatic discharge protection circuits according to claim 12, wherein said the first resistance has one first resistance value Z
1, described the second resistance has one second resistance value Z
2, described the 3rd resistance has one the 3rd resistance value Z
3, described the first switch has a critical voltage V
thp, described second switch has a critical voltage V
thn; When described input voltage is an operating voltage V
ddtime, described the first voltage V
ptransient voltage, and described second voltage V
ntransient voltage meet following equation:
With
16. electrostatic discharge protection circuits according to claim 15, when described input voltage is an electrostatic potential V
eSDtime, wherein, described the first voltage V
ptransient voltage, and described second voltage V
ntransient voltage meet following equation:
With
17. electrostatic discharge protection circuits according to claim 16, wherein when described input voltage is an electrostatic potential, described decision circuitry produces described output voltage according to the conduction impedance value of described the first switch and described second switch, and described output voltage to make described switching circuit be conducting state.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010226292.2A CN102315633B (en) | 2010-07-06 | 2010-07-06 | Electrostatic protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010226292.2A CN102315633B (en) | 2010-07-06 | 2010-07-06 | Electrostatic protection circuit |
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| CN102315633A CN102315633A (en) | 2012-01-11 |
| CN102315633B true CN102315633B (en) | 2014-04-23 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN102651547B (en) * | 2012-01-12 | 2013-06-05 | 京东方科技集团股份有限公司 | ESD (Electro-Static discharge) protection circuit and display device comprising same |
| CN107565537B (en) * | 2017-09-29 | 2019-09-20 | 广州慧智微电子有限公司 | A kind of esd protection circuit and method |
| US11063772B2 (en) * | 2017-11-24 | 2021-07-13 | Ememory Technology Inc. | Multi-cell per bit nonvolatile memory unit |
| WO2020051832A1 (en) * | 2018-09-13 | 2020-03-19 | 深圳市汇顶科技股份有限公司 | Electrostatic discharge protection circuit and integrated circuit chip |
| CN111679709B (en) * | 2020-06-16 | 2022-03-11 | 武汉光迅科技股份有限公司 | Voltage generating circuit and method |
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|---|---|---|---|---|
| US6621679B1 (en) * | 2001-12-05 | 2003-09-16 | National Semiconductor Corporation | 5V tolerant corner clamp with keep off circuit |
| CN101207119A (en) * | 2007-12-25 | 2008-06-25 | 上海宏力半导体制造有限公司 | Chip electrostatic protection circuit with CMOS output drive |
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| US8064175B2 (en) * | 2005-09-15 | 2011-11-22 | Rambus Inc. | Power supply shunt |
| TWI284409B (en) * | 2006-02-09 | 2007-07-21 | Winbond Electronics Corp | Electrostatic discharge protection device and integrated circuit utilizing the same |
| US20080316659A1 (en) * | 2007-06-19 | 2008-12-25 | Ismail Hakki Oguzman | High voltage esd protection featuring pnp bipolar junction transistor |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6621679B1 (en) * | 2001-12-05 | 2003-09-16 | National Semiconductor Corporation | 5V tolerant corner clamp with keep off circuit |
| CN101207119A (en) * | 2007-12-25 | 2008-06-25 | 上海宏力半导体制造有限公司 | Chip electrostatic protection circuit with CMOS output drive |
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