TW201707184A - Electrostatic discharge protection circuit and integrated circuit - Google Patents

Abstract

The present invention relates to an electrostatic discharge (ESD) protection circuit. The ESD protection circuit includes an ESD detection unit, an ESD unit and a switch unit. The ESD detection unit is coupled to the first conductive pad. The ESD detection unit is configured to detect whether the first conductive pad having an ESD phenomenon and outputs a detect signal. The ESD unit is configured to transmit an ESD current between a first conductive pad and a second conductive pad when the first conductive pad having the ESD phenomenon. The switch unit is coupled between the first conductive pad and a core operation circuit. The switch unit is configured to control the first conductive pad is electric conducted to or disconnected to the core operation circuit according to the detection signal. The present invention further relates an integrated circuit (IC) including the ESD protection circuit.

Description

Electrostatic discharge protection circuit and integrated circuit

The present invention relates to an electrostatic discharge protection circuit, and more particularly to an electrostatic discharge protection circuit for preventing an electrostatic discharge current from flowing into a core working circuit when an electrostatic discharge occurs.

An integrated circuit (IC) or some electronic components may be damaged by electrostatic discharge (ESD) in actual use environments. For example, when the integrated circuit is transported or assembled, the electrostatic charge is quickly transferred from the external object to the input due to an external object with an electrostatic charge, such as the human body, touching the input/output terminals (I/O ports) of the integrated circuit. The output end generates an electrostatic discharge phenomenon, and when the electrostatic discharge occurs, a large electrostatic voltage and an electrostatic current can be generated, which is sufficient to damage the core working circuit inside the integrated circuit. Wherein, the core working circuit is all working circuits in the integrated circuit, such as logic circuit, signal processing circuit and the like. Therefore, a low-resistance bypass must be placed between the input/output terminals of the integrated circuit to act as an electrostatic current venting path to prevent the electrostatic circuit from entering the core operating circuit.

However, when the electrostatic current is vented from the low-resistance bypass, part of the static current will enter the core working circuit from the input/output terminal. Therefore, it is urgent to prevent the electrostatic current from entering the core working circuit while the electrostatic current is venting. Solve the problem.

In view of this, it is necessary to provide a highly reliable electrostatic discharge protection circuit.

Further, an integrated circuit having the aforementioned electrostatic discharge protection circuit is provided.

An electrostatic discharge protection circuit comprising:

An ESD detecting unit is coupled between a first conductive end and a second conductive end, configured to detect whether the first conductive end has an electrostatic discharge, and output a corresponding detection signal, the first The conductive end is used to provide a programming voltage or transmit a data signal to a core working circuit;

An electrostatic discharge unit coupled between the first conductive end and the second conductive end for venting an electrostatic charge accumulated at the first conductive end to the second conductive end;

a switching unit is coupled between the first conductive end and a working circuit for electrically connecting or disconnecting the first conductive end to the working circuit according to the detecting signal; the switching unit includes selecting a switch, a first control switch, and a second control switch, the selection switch is coupled to the first conductive end and the working circuit, and the first control switch and the second control switch are connected in series to the first conductive end and the third conductive end Controlling the selection switch to be in an on or off state;

When the first conductive end has an electrostatic discharge current, the detecting signal controls the first control switch to be in an on state, so that the selection switch is in an off state, and the first conductive end is electrically disconnected from the working circuit;

When the first conductive end provides the programming voltage or transmits a data signal to the core working circuit, the detecting signal controls the first control switch to be in an off state, and the second control switch is in an on state under an open voltage control The selection switch is in an on state under the voltage control of the third conductive end, and the first conductive end is electrically connected to the working circuit.

An integrated circuit includes: a first conductive end; a second conductive end; a core working circuit, wherein the core working circuit is configured to provide a programming voltage or a transmitted data signal from the first conductive end; Electrostatic discharge protection circuit.

Compared with the prior art, the switch unit controls the on/off of the selection switch coupled between the first conductive end and the core working circuit by the first control switch and the second control switch, so that when the integrated circuit is working normally, The first conductive end is normally electrically connected to the core working circuit, and during the transportation or assembly process of the integrated circuit, when the electrostatic discharge phenomenon occurs at the first conductive end due to human contact, when the electrostatic circuit is vented by the electrostatic discharge unit, At the same time, the first conductive end can be electrically disconnected from the core working circuit accurately and reliably, and the electrostatic circuit is prevented from entering the core working circuit.

100, 200, 300, 400, 500. . . Integrated circuit

10, 20, 30, 40, 50. . . Electrostatic discharge protection circuit

101, 201, 301, 401, 501. . . First conductive end

102, 202, 302, 402, 502. . . Second conductive end

X. . . Core working circuit

110, 210, 310, 410, 510. . . Electrostatic discharge detection unit

110a, 410a. . . Detection input

110b, 410b. . . Detection output

111, 411. . . Resistive component

112, 412. . . Capacitive component

120, 220, 320, 420, 520. . . Electrostatic discharge starting unit

120a, 520a. . . First input

120b, 520b. . . First output

121. . . First switch

122. . . Second switch

130, 230, 330, 430, 530. . . Electrostatic discharge unit

130a. . . Startup

131. . . Discharge switch

140, 240, 340, 440, 540. . . Switch unit

140a. . . First transmission end

140b. . . Second transmission end

140c. . . First control terminal

140d, 240d, 540d. . . Second control terminal

141, 241, 341, 441, 541. . . switch

142, 242, 342, 442, 542. . . First control switch

143, 243, 343, 443, 543. . . Second control switch

144, 244, 344, 444, 544. . . Current limiting unit

A. . . Control node

P1. . . First transistor

N1. . . Second transistor

N2. . . Third transistor

P2. . . Fourth transistor

P3. . . Fifth transistor

N3. . . Sixth transistor

P4. . . Seventh transistor

N4. . . Eighth transistor

P5. . . Ninth transistor

R0. . . resistance

C0. . . capacitance

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram showing the circuit of an electrostatic discharge protection circuit in a first embodiment of the present invention.

2 is a detailed circuit configuration diagram of the electrostatic discharge protection circuit shown in FIG. 1.

3 is a circuit configuration diagram of an electrostatic discharge protection circuit in a second embodiment of the present invention.

4 is a circuit configuration diagram of an electrostatic discharge protection circuit in a third embodiment of the present invention.

Fig. 5 is a circuit diagram showing the structure of an electrostatic discharge protection circuit in a fourth embodiment of the present invention.

Fig. 6 is a circuit diagram showing the structure of an electrostatic discharge protection circuit in a fifth embodiment of the present invention.

The specific structure of the electrostatic discharge protection circuit of the present invention will be specifically described below with reference to the accompanying drawings.

Please refer to FIG. 1, which is a circuit block diagram of an electrostatic discharge protection circuit 10 of the present invention. The electrostatic discharge protection circuit 10 is applied to electrostatic discharge protection between any one of the input/output terminals (I/O terminals) of the integrated circuit 100 and the core operating circuit X. In this embodiment, any one of the input/output terminals is defined as a first conductive terminal 101, and the core working circuit X is a working circuit of the integrated circuit 100, such as a logic circuit, a signal processing circuit, and the like.

It should be noted that the electrostatic discharge may occur during the production, transportation, assembly, and use of the integrated circuit 100, including three types: Human Body Model (HBM), Machine Model (MM), and charging device model. (Charged Device Model, CDM), the present embodiment mainly describes the protection of the human body model HBM that generates electrostatic discharge at the first conductive end 101 of the human body integrated circuit 100.

The integrated circuit 100 may be an integrated circuit such as a one-time programmable nonvolatile memory or a multi-programmable nonvolatile memory. The first conductive end 101 is used to supply the core working circuit X with the programming voltage Vp and the input or output data signal (Data). The electrostatic charge carried by the human body mainly generates an electrostatic discharge at the first conductive end 101, and the electrostatic current generated by the electrostatic discharge is relatively easy to enter the core working circuit X from the first conductive end 101. The electrostatic discharge protection circuit 10 functions to quickly and accurately vent the electrostatic current from the first conductive terminal 101 to the second conductive end 102. In this embodiment, the second conductive end 102 is a ground terminal or a power terminal, thereby preventing static electricity. The current enters the core working circuit X. The core working circuit X described in this embodiment is mainly a programmable logic circuit, such as a programmable memory unit, a logic processing circuit, and the like.

The integrated circuit 100 includes a plurality of states. This embodiment mainly describes two states of the normal working state and the electrostatic discharge state of the integrated circuit 100. The normal working state of the integrated circuit includes a burning state and an information transmission state. The programming state is mainly to provide a programming voltage Vp from the first conductive terminal 101, and the programming voltage Vp starts the core working circuit X to perform a writing operation of the information. The information transmission state is mainly transmitted by the first conductive end 101. At this time, the first conductive end 101 is the same as the power supply voltage Vd of the integrated circuit.

When the integrated circuit 100 is in the normal working state, the programming voltage Vp or the power supply voltage Vd is loaded from the first conductive terminal 101. In this embodiment, the programming voltage Vp can be 7V, and the power supply voltage is 3.3V.

When the integrated circuit 100 is in an electrostatic discharge state, that is, the integrated circuit 100 is in a state of being in contact with the human body in transportation, packaging, etc., at this time, the integrated circuit 100 is not in an active state, and the power is not loaded at the same time. Voltage, whereby the first conductive terminal 101 does not load the programming voltage Vp or the power supply voltage Vd, and at the same time, the power supply terminal VDD does not provide the power supply voltage Vd, and at this time, the voltage of the first conductive terminal 101 is equal to its accumulation. Electrostatic charge electrostatic voltage Ve.

In this embodiment, the electrostatic discharge protection circuit 10 includes an electrostatic discharge detecting unit 110, an electrostatic discharge starting unit 120, an electrostatic discharge unit 130, and a switching unit 140.

The ESD detecting unit 110 is coupled between the first conductive end 101 and the second conductive end 102 for detecting that the first conductive end 101 is in a normal working state or an electrostatic charge discharging state. The ESD detecting unit 110 includes a detecting input terminal 110a and a detecting output terminal 110b. The detecting input terminal 110a is coupled to the first conductive end 101, and the ESD detecting unit 110 outputs the voltage of the first conductive end 101 detected by the detecting input terminal 110a, and outputs the self-detecting output terminal 110b. A detection signal is used to characterize whether the first conductive terminal 101 has an electrostatic discharge.

Specifically, for example, when the first conductive terminal 101 loads the programming voltage Vp or the voltage Vd, the electrostatic discharge detecting unit 110 outputs a high potential signal from the detecting output terminal 110b; when the first conductive terminal 101 collects the electrostatic charge and When the electrostatic discharge phenomenon occurs, the ESD detecting unit 110 outputs a low potential signal from the detecting output terminal 110b. In this embodiment, the high potential signal can be 3.3V-7V, and the low potential signal can be 0V.

The ESD starting unit 120 is also coupled between the first conductive end 101 and the second conductive end 102. The ESD starting unit 120 is also coupled to the ESD detecting unit 110 and the ESD unit 130.

The electrostatic discharge activation unit 120 includes a first input terminal 120a and a first output terminal 120b. Specifically, the first input end 120a is coupled to the detection output end 110b, and the first output end 120b is coupled to the ESD unit 130. The ESD activation unit 120 outputs the detection signal according to the detection signal from the first output end 120b. An activation signal opposite to the phase of the detection signal is sent to the electrostatic discharge unit 130 to activate the electrostatic discharge unit 130 for the cathartic transmission of the electrostatic current.

The electrostatic discharge unit 130 is coupled between the first conductive end 101 and the second conductive end 102 for venting the electrostatic current generated by the electrostatic discharge of the first conductive end 101 to the second conductive end 102. The electrostatic discharge unit 130 can be coupled to the electrostatic discharge starting unit 120, and can start discharging the electrostatic current by starting the activation signal, and can also directly discharge the electrostatic current without starting the activation signal. In this embodiment, the electrostatic discharge unit 130 includes a start end 130a coupled to the first output end 120b for receiving the start signal, and the electrostatic discharge unit 130 starts to operate under the driving of the start signal and vents the electrostatic current. .

The switch unit 140 is coupled between the first conductive end 101 and the core working circuit X, and is also coupled to the detecting output end 110b of the ESD detecting unit 110 for controlling the first conductive end 101 according to the detecting signal. Selectively electrically or electrically disconnected from the core working circuit X, so that when the core working circuit X is in a normal working state, it can be electrically electrically connected from the first conductive terminal 101 and perform signal transmission, and at the same time When the first conductive end 101 is accumulated with electrostatic charge or has an electrostatic discharge phenomenon, the core working circuit X can be electrically disconnected from the first conductive end 101 to prevent the electrostatic current from entering the core working circuit X and causing damage to its components.

The switch unit 140 includes a first transmission end 140a, a second transmission end 140b, a first control end 140c, and a second control end 140d. The first transmission end 140a is coupled to the first conductive end 101, and the second transmission end 140b is coupled to the first transmission end 140b. The core control circuit X, the first control terminal 140c is coupled to the detection output terminal 110b, and the second control terminal 140d is coupled to the power supply terminal VDD. The switch unit 140 receives the detection signal by the first control terminal 140c to selectively control the first transmission end 140a and the second transmission end 140b to be electrically or electrically disconnected, and also by the second control end. Whether 140d receives an open voltage to control the conduction between the first transmission end 140a and the second transmission end 140b.

The turn-on voltage indicates that the first conductive terminal 101 is in an active state or in an electrostatic discharge state. When the first conductive terminal 101 is in a normal working state, the voltage of the turn-on voltage is equal to the power supply voltage Vd, which is a high voltage signal; when the first The conductive terminal 101 is in an electrostatic discharge state, and the turn-on voltage is a floating low potential signal, so that the switch unit 140 is caused to reliably electrically conduct the first conductive terminal 101 and the core working circuit X when the integrated circuit 100 operates normally.

Specifically, please refer to FIG. 2. FIG. 2 is a schematic structural diagram of a specific circuit of the ESD protection circuit 10 of FIG.

The electrostatic discharge detecting unit 110 includes a resistive element 111 and a capacitive element 112. The resistive component 111 is coupled between the first conductive end 101 and the detecting output end 110b. The capacitive component 112 is coupled between the detection output terminal 110b and the second conductive terminal 102.

The resistive component 111 and the capacitive component 112 form an RC filter circuit for detecting whether the first conductive terminal 101 has an electrostatic discharge phenomenon, and the corresponding detection signal is output from the detection output terminal 110b.

In this embodiment, the resistive component 111 is a resistor R0, and the capacitive component 112 is a capacitor C0.

The electrostatic discharge starting unit 120 includes a first switch 121 and a second switch 122. The first switch 121 is coupled between the first conductive end 101, the first input end 120a and the first output end 120b, and the second switch 122 is coupled to the first input end 120a, the first output end 120b and the second conductive end. Between 102, the first switch 121 and the second switch 122 form an inverter structure between the first input terminal 120a and the first output terminal 120b.

In this embodiment, the first switch 121 is a P-type first transistor P1, the gate of the first transistor P1 is coupled to the first input end 120a, and the source and the base end are coupled to the first conductive end 101. The drain is coupled to the first output terminal 120b.

The second switch 122 is an N-type second transistor N1. The gate of the second transistor N1 is coupled to the first input end 120a, the drain is coupled to the first output end 120b, and the source is coupled to the base end. The second conductive end 102.

The electrostatic discharge unit 130 further includes a discharge switch 131 coupled to the first conductive end 101, the second conductive end 102, and the start end 130a for being in an on state or an off state under the start signal control, when the discharge switch When the 131 is in the on state, the first conductive end 101 and the second conductive end 102 are electrically connected to provide a venting path for the electrostatic current of the first conductive end 101; when the discharge switch 131 is in the off state, the first conductive end 101 is The second conductive end 102 is electrically disconnected. The discharge switch 131 is an N-type third transistor N2, the gate of the third transistor N2 is coupled to the starting end 130a, and the drain is coupled to the first conductive end 101, the source ( Source) is coupled to the second conductive end 102 with a body/bulk.

The switch unit 140 includes a selection switch 141, a first control switch 142, a second control switch 143, and a current limiting unit 144.

The selection switch 141 is coupled between the first conductive end 101 and the core working circuit X. In this embodiment, the selection switch 141 is a P-type fourth transistor P2, and the source and the base end of the fourth transistor P2. The first conductive terminal 101 is coupled to the core working circuit X, and the gate is coupled to the control node A.

The first control switch 142 is coupled to the first conductive terminal 101, the first control terminal 140c, and the control node A. In this embodiment, the first control switch 142 is a P-type fifth transistor P3, and the fifth transistor P3 is The gate is coupled to the first control terminal 140c, the source and the base end are coupled to the first transmission end 140a, and the drain is coupled to the control node A.

The current limiting unit 144 is coupled between the control node A and the second control switch 143 for limiting the current flowing through the second control switch 143 to more accurately control the voltage of the node A.

In this embodiment, the current limiting unit 144 is a current limiting resistor. Preferably, the current limiting unit 144 has a resistance value of 10 KΩ.

The second control switch 143 is coupled between the current limiting unit 144, the second conductive end 102, the second control end 140d, and the third conductive end 103 for controlling the control node A under the control of the second control terminal 140d. The second conductive terminal 102 is electrically or electrically disconnected, so that the voltage of the control node A is equal to the voltage of the third conductive terminal 103 when the integrated circuit 100 is in the normal working state, thereby controlling the selection switch 141 to be in an on state. In this embodiment, the third conductive end 103 is a ground end, and the voltage of the third conductive end 103 is 0V.

Specifically, the second control switch 143 is an N-type sixth transistor N3, the gate of the sixth transistor N3 is coupled to the second control terminal 140d, the drain is coupled to the current limiting unit 144, and the source is The base ends are respectively coupled to the second conductive ends 102.

The working process and principle of the electrostatic discharge protection circuit 10 will be specifically described below with reference to FIG.

When the integrated circuit 100 is in a normal working state, the first conductive terminal 101 provides a programming voltage VP or a power supply voltage Vd, and the detecting input terminal 110a of the electrostatic discharge detecting unit 110 loads the programming voltage, and the resistive element 111 and The RC filter circuit formed by the capacitive component 112 outputs a high potential detection signal at the detection output terminal 110b.

The first input terminal 120a of the electrostatic discharge starting unit 120 receives the high-potential detection signal from the detection output terminal 110b. The first switch 121 is in an off state under the control of the high potential detection signal, and the second switch 122 is in an on state under the control of the high potential detection signal, thereby outputting a low potential activation signal from the first output terminal 120b.

The electrostatic discharge unit 130 is in an off state under the control of the driving signal of a low potential.

The first control terminal 140c of the switch unit 140 receives the high-potential detection signal from the detection output terminal 110b, whereby the first control switch 142 is in an off state.

The second control terminal 140d receives the power supply voltage Vd from the power supply terminal VDD as the turn-on voltage, and the second control switch 143 is in an on state, whereby the control node A and the third conductive terminal 103 are electrically turned on, and is equal to the second conductive terminal 102. a low potential voltage, whereby the selection switch 141 is in an on state, so that the first conductive end 101 is electrically connected to the core working circuit X, and the first conductive end 101 provides a programming voltage VP to be transmitted to the core working circuit X, Thereby, the core working circuit X is activated, so that the core working circuit X starts to work.

When the integrated circuit 100 is in an electrostatic charge or in an electrostatic discharge state, the voltage of the first conductive terminal 101 is equal to the electrostatic voltage Ve of the accumulated electrostatic charge, and the power supply terminal VDD does not supply the power supply voltage Vd, and is in a floating state (floating) ).

At this time, when the electrostatic voltage Ve is a positive pulse, the resistive element 111 and the capacitive element 112 have a delay time τ due to the delay characteristic of the RC filter circuit, whereby the electrostatic voltage Ve is applied from the detection input terminal 110a to the detection. The output voltage of the output terminal 110b also has a delay time τ. Therefore, during the delay time τ, the detection output terminal 110b outputs a low potential detection signal, and the low potential detection signal is loaded to the first input end. 120a, the first output terminal 120b outputs a high-potential start signal to the start end 130a of the electrostatic discharge unit 130.

The discharge switch 131 of the electrostatic discharge unit 130 is in an on state under the control of the high-potential activation signal, so that the first conductive end 101 and the second conductive end 102 are electrically connected to provide a static discharge current for the first conductive end 101. Quick catharsis path. It can be understood that, within the delay time τ, the electrostatic discharge current of the first conductive terminal 101 has been vented, and the delay time τ can be adjusted according to the actual circuit.

At the same time, the low-potential detection signal is applied to the first control terminal 140c of the switch unit 140, and the first control switch 142 is in an on state under the control of the low-potential detection signal, whereby the control node A is at a high potential, correspondingly, The selection switch 141 is in an off state under the high potential control of the control node A, so that the first conductive terminal 101 and the core working circuit X are electrically disconnected, and the electrostatic current formed by the electrostatic charge is prevented from entering the core working circuit.

If the electrostatic voltage Ve is a negative pulse, the parasitic diode (not shown) of the discharge switch 131 is turned on, and the electrostatic current may provide a venting conductive path between the first conductive end 101 and the second conductive end 102.

Compared with the prior art, the switch unit 140 controls the conduction or the off of the selection switch 141 coupled between the first conductive terminal 101 and the core working circuit X by the first control switch 142 and the second control switch 143, thereby When the integrated circuit 100 is in normal operation, the first conductive end 101 is normally electrically connected to the core working circuit X, and during the transportation or assembly process of the integrated circuit 100, when the first conductive end 101 is electrostatically discharged due to human contact. When the electrostatic circuit is vented by the electrostatic discharge unit 130, the first conductive end 101 can be electrically and reliably disconnected from the core working circuit X, and the electrostatic circuit is prevented from entering the core working circuit X.

Please refer to FIG. 3 , which is a schematic diagram of the circuit structure of the electrostatic discharge protection circuit 20 according to the second embodiment of the present invention.

The electrostatic discharge protection circuit 20 of the present embodiment has substantially the same structure as the electrostatic discharge protection circuit 10 of the first embodiment, except that the switch unit 240 includes only the selection switch 241, the first control switch 242, and the second control switch 243, and The current limiting unit 144 of the ESD protection circuit 10 is not included. The second control switch 243 is directly coupled between the control node A, the third conductive terminal 203, and the second control terminal 240d, thereby omitting the space occupied by the current limiting unit 144. The layout space of the electrostatic discharge protection circuit 20 is increased.

Please refer to FIG. 4 , which is a schematic diagram of the circuit structure of the electrostatic discharge protection circuit 30 according to the third embodiment of the present invention.

The electrostatic discharge protection circuit 30 of the present embodiment has substantially the same structure as the electrostatic discharge protection circuit 10 of the first embodiment, except that the electrostatic discharge protection circuit 30 does not include the electrostatic discharge activation unit 120, and the electrostatic discharge unit 330 is directly It is coupled between the first conductive end 301 and the second conductive end 302, and does not need to detect the activation of the signal, but when the first conductive end 301 is accumulated with electrostatic charge or has an electrostatic discharge phenomenon, the parasitic bi-carrier power The crystal (not labeled) will automatically be in a conducting state to provide a conduction loop for the electrostatic current, venting the electrostatic current to the second conductive terminal 302.

Specifically, the electrostatic discharge unit 330 is a gate-grounded N-type transistor, the drain of the N-type transistor is coupled to the first conductive end 301, and the gate, the source, and the base end are coupled to the second conductive end. 102, which constitutes electrostatic discharge protection with a GG-NMOS structure.

Please refer to FIG. 5 , which is a schematic structural diagram of a circuit of an electrostatic discharge protection circuit 40 according to a fourth embodiment of the present invention.

The electrostatic discharge protection circuit 40 of the present embodiment has substantially the same structure as the electrostatic discharge protection circuit 10 of the first embodiment. The difference is only in the electrostatic discharge detecting unit 410. The resistive element 411 is a P-type seventh transistor. P4, the gate of the seventh transistor P4 is coupled to the ground end, the source and the base end are coupled to the detection input end 410a, and the drain is coupled to the detection output end 410b.

The capacitive element 412 is an N-type eighth transistor N4, and the gate of the eighth transistor N4 is coupled to the detection output end 410b as one of the electrode ends of the capacitive element, the base end, the source and the The drain is coupled to the second conductive end 402 as another electrode end of the capacitive element.

By forming the RC filter circuit by the seventh transistor P4 and the eighth transistor N4, the space occupied by the components can be reduced, and the component design space of the electrostatic discharge protection circuit 40 and the integrated circuit 400 can be improved.

Please refer to FIG. 6, which is a circuit diagram of an electrostatic discharge protection circuit 50 according to a fifth embodiment of the present invention.

The electrostatic discharge protection circuit 50 of the present embodiment has substantially the same structure as the electrostatic discharge protection circuit 40 of the fourth embodiment. The only difference is that the switch unit 540 further includes a third control switch 545, and the third control switch 545 is coupled to the first The second control terminal 540d, the first input terminal 520a and the first output terminal 520b are configured to provide an opening voltage for the second control terminal 540d to control the third control switch 545 to be in an on state.

Specifically, the third control switch 545 is a P-type ninth transistor P5, the NMOS of the ninth transistor P5 is coupled to the second control terminal 540d, and the gate is coupled to the first output terminal 520b, the source The first input end 520a is coupled to the base end at the same time.

Therefore, when the integrated circuit is in a normal working state or a standby state, the first input terminal 520a provides a working voltage of 3.3V or a programming voltage of 7V to the source of the third control switch 545, and the first output terminal 520b Providing a reverse voltage of 0V to the gate of the third control switch 545, whereby the third control switch 545 is in an on state, and at the same time, providing a voltage of at least 3.3V to the second control terminal 540d, thereby making The second control switch 543 and the selection switch 541 are in an on state, and the first conductive terminal 501 provides a programming voltage (7V) or a power supply voltage (3.3V) to the core operating circuit X.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. However, the above description is only the preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and equivalent modifications or variations made by those skilled in the art in light of the spirit of the present invention are It should be covered by the following patent application.

no

100‧‧‧ integrated circuit

10‧‧‧Electrostatic discharge protection circuit

101‧‧‧First conductive end

102‧‧‧Second conductive end

103‧‧‧ third conductive end

X‧‧‧ core working circuit

110‧‧‧Electrostatic Discharge Detection Unit

110a‧‧‧Detection input

110b‧‧‧Detection output

111‧‧‧Resistive components

112‧‧‧Capacitive components

120‧‧‧Electrostatic discharge starter unit

120a‧‧‧ first input

120b‧‧‧first output

130‧‧‧Electrostatic discharge unit

130a‧‧‧Startup

131‧‧‧Discharge switch

140‧‧‧Switch unit

140a‧‧‧first transmission end

140b‧‧‧second transmission end

140c‧‧‧first control end

140d‧‧‧second control terminal

141‧‧‧Selection switch

142‧‧‧First control switch

143‧‧‧Second control switch

144‧‧‧ Current limiting unit

A‧‧‧ control node

P1‧‧‧First transistor

N1‧‧‧second transistor

N2‧‧‧ third transistor

P2‧‧‧ fourth transistor

P3‧‧‧ fifth transistor

N3‧‧‧ sixth transistor

P4‧‧‧ seventh transistor

N4‧‧‧ eighth transistor

P5‧‧‧ ninth transistor

R0‧‧‧ resistance

C0‧‧‧ capacitor

Claims (18)

An electrostatic discharge protection circuit comprising:
An ESD detecting unit is coupled between a first conductive end and a second conductive end, configured to detect whether the first conductive end has an electrostatic discharge, and output a corresponding detection signal, the first The conductive end is used to provide a programming voltage or transmit a data signal to a core working circuit;
An electrostatic discharge unit coupled between the first conductive end and the second conductive end for venting an electrostatic charge accumulated at the first conductive end to the second conductive end; and a switching unit coupled to the first Between a conductive end and the core working circuit, the first conductive end is electrically connected or disconnected from the core working circuit according to the detecting signal; the switching unit includes a selection switch, a first control switch, and a second control switch, the selection switch is coupled to the first conductive end and the core working circuit, the first control switch and the second control switch are connected in series between the first conductive end and the third conductive end to control the selection The switch is in an on or off state;
When the first conductive end has an electrostatic discharge current, the detecting signal controls the first control switch to be in an on state, so that the selection switch is in an off state, and the first conductive end is electrically disconnected from the core working circuit;
When the first conductive end provides the programming voltage or transmits a data signal to the core working circuit, the detecting signal controls the first control switch to be in an off state, and the second control switch is in an on state under an open voltage control The selection switch is in an on state under the voltage control of the third conductive end, and the first conductive end is electrically connected to the core working circuit. The ESD protection circuit of claim 1, wherein the switch unit comprises a first transmission end, a second transmission end, a first control end and a second control end, and a control node, wherein the first transmission end is coupled to the a first conductive end, the second transmitting end is coupled to the core working circuit, the first control end is connected to the detecting signal, the second control end receives the turning-on voltage, and the selecting switch is coupled to the first transmitting end, The second control switch is coupled to the first transmission end, the first control end, and the control node, and the second control switch is coupled to the control node, the second control end, and the third conductive end. The ESD protection circuit of claim 2, wherein the selection switch and the second switch are P-type transistors, and the source of the P-type transistor is electrically connected to the first transmission end, and the gate is electrically connected. The second transmission end is coupled to the control node, the source of the first control switch is electrically connected to the first transmission end, the drain is coupled to the control node, and the gate is coupled to the first control end, The third switch is an N-type transistor, the source of the third switch is electrically connected to the control node, the drain is electrically connected to the third conductive end, and the gate is coupled to the second control end. The electrostatic discharge protection circuit of claim 2, wherein the control node and the second control switch further comprise a current limiting unit for limiting a current flowing through the second control switch. The electrostatic discharge protection circuit of claim 4, wherein the current limiting unit is a resistor having a resistance value of 10 kΩ. The ESD protection circuit of claim 3 or 4, wherein the ESD detection unit includes a detection input end and a detection output end, the detection input end is coupled to the first conductive end, and the detection output is The end is configured to output the detection signal, the electrostatic discharge unit includes a resistive component and a capacitive component, the resistive component is coupled between the detection input end and the detection output end, and the capacitive component is coupled to Between the detection output end and the second conductive end, the resistive element and the capacitive element form an RC filter circuit. The electrostatic discharge protection circuit of claim 6, wherein the resistive component is a resistor, and the resistive component is a capacitor. The electrostatic discharge protection circuit of claim 7, wherein the electrostatic discharge unit is a gate-grounded N-type transistor, and the gate, the source and the base end of the N-type transistor are coupled to the second conductive end, The drain is coupled to the first conductive end to form a GG-NMOS structure. The electrostatic discharge protection circuit of claim 8, wherein the turn-on voltage is a power supply voltage of the core operating circuit. The electrostatic discharge protection circuit of claim 6, wherein the resistive component is a P-type transistor, the gate of the P-type transistor is coupled to the ground, and the source and the substrate are coupled to the detection input. The drain electrode is coupled to the detection output end, the capacitive component is an N-type transistor, and the gate of the N-type transistor is coupled to the detection output end as one of the electrode ends of the capacitive component, the base end The source and the drain are coupled to the second conductive end as the other electrode end of the capacitive element. The electrostatic discharge protection circuit of claim 10, wherein the electrostatic discharge protection circuit further includes an electrostatic discharge activation unit coupled between the first conductive end and the second conductive end, the static electricity The discharge starting unit includes a first input end coupled to the first output end, the first input end is coupled to the detection output end for receiving the detection signal, and the first output end is coupled to the electrostatic discharge unit, the static electricity The discharge starting unit is configured to output an activation signal opposite to the phase of the detection signal according to the detection signal. The ESD protection circuit of claim 11, wherein the ESD activation unit includes a first switch and a second switch, the first switch is coupled to the first conductive end, the first input end, and the The first switch is coupled between the first input end, the first output end and the second conductive end, the first switch and the second switch are at the first input end and the second switch An inverter structure is formed between the outputs. The electrostatic discharge protection circuit of claim 10, wherein the electrostatic discharge unit is an N-type transistor, the gate of the N-type transistor is coupled to the first output end, and the drain is coupled to the first conductive end The source and the base end are coupled to the second conductive end. The ESD protection circuit of claim 10, wherein the turn-on voltage indicates that the first conductive end is in an active state or in an electrostatic discharge state, and when the first conductive end is in an active state, the start signal is in a high voltage state, And causing the voltage of the control node to control the selection switch to be in an on state; when the first conductive end is in an electrostatic discharge state, the startup signal is a low potential signal, and the voltage of the control node controls the selection switch to be in an off state, preventing static electricity Current enters the core operating circuit. The ESD protection circuit of claim 14, wherein the activation signal is a power supply voltage of the core operating circuit. The ESD protection circuit of claim 15, wherein the switch unit further includes a third control switch, the third control switch is a P-type transistor, and the gate of the P-type transistor is electrically connected to the first The output end of the P-type transistor is coupled to the detection terminal and the first input end, and the drain of the P-type transistor is coupled to the gate of the third switch. The electrostatic discharge protection circuit of claim 1, wherein the second conductive end and the third conductive end are both grounded. An integrated circuit comprising:
a first conductive end;
a second conductive end;
A core working circuit for providing a programming voltage or a transmitted data signal from the first conductive terminal; and an electrostatic discharge protection circuit according to any one of claims 1-5.