KR101006095B1 - A electrostatic discharge protection circuit of activating a low voltage - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low voltage operation type static electricity protection circuit, comprising: a first static electricity induction unit connected between a first node and a ground voltage line and inducing static electricity when positive static electricity flows; and a connection between the first node and a power supply voltage line And a second electrostatic induction unit for inducing static electricity when negative static electricity is introduced, the second node connected to the input / output pad and the ground voltage line, and connected to the first electrostatic induction unit and induced by the first electrostatic induction unit. A first discharge part that is turned on with positive static electricity to discharge the positive static electricity, and is connected between the second node connected to the input / output pad and the power supply voltage line and connected to the second static electricity induction part, and by the second static electricity induction part. A second discharge part and the first node and the second discharge part which are turned on by the induced negative static electricity to discharge the negative static electricity The present invention relates to a low voltage operation type static electricity protection circuit capable of electrostatic discharge at low voltage without increasing a capacitor component at a pin by including a resistor connected between nodes.

ESD, electrostatic induction, electrostatic discharge, diode chain

Description

Low Voltage Operated Static Protection Circuit {A ELECTROSTATIC DISCHARGE PROTECTION CIRCUIT OF ACTIVATING A LOW VOLTAGE}

The present invention relates to a static electricity protection circuit, and more particularly, to a low voltage operation type static electricity protection circuit that protects a semiconductor device from static electricity by quickly discharging static electricity flowing into an input / output pad of a semiconductor device at a low voltage.

In general, when a semiconductor integrated circuit is in contact with a human body or a machine, the static electricity charged in the human body or the machine is discharged into the semiconductor, and thus the semiconductor internal circuit may be greatly damaged.

The semiconductor integrated circuit configures an electrostatic protection circuit between the input / output pad and the semiconductor internal circuit to protect the semiconductor internal circuit from such damage.

However, as the semiconductor technology becomes faster and more highly integrated, the gate oxide film thickness of the semiconductor internal circuit device is gradually thinner, and thus the gate breakdown voltage is also lowered.

Therefore, as the difference between the operating voltage of the static electricity protection device and the gate breakdown voltage of the semiconductor internal circuit in the static electricity protection circuit is gradually reduced, the gate of the internal circuit device is destroyed before the static electricity introduced into the semiconductor is discharged by the static electricity protection device. May occur.

Therefore, an electrostatic protection circuit employed in a high speed and highly integrated semiconductor circuit requires a technology that can further lower the operating voltage of the electrostatic protection element.

1 is a circuit diagram of a conventional static electricity protection circuit, and shows an example of a static electricity protection circuit having a lower operating voltage.

Referring to FIG. 1, the conventional static electricity protection circuit 100 includes a CDM transistor (CHARGE DEVICE MODEL TRANSISTOR, hereinafter referred to as a CDM transistor) that prevents the gate voltage of the internal circuit 150 from rising. 120 and a power clamp 130 for discharging static electricity.

Induction unit 110 is composed of a first diode 111 and a second diode 112, one end of the first diode is connected to the ground power line 104, the other end is one end and the node 113 of the second diode (112). The other end of the second diode 112 is connected to the power supply voltage line 102.

The node 113 of the first diode 111 and the second diode 112 is connected to the input / output data line 103 and connected to the CDM transistor unit 120 with the resistor 140 therebetween.

CDM transistor unit 120 is composed of a first GCNMOS transistor 121 and a second GCNMOS transistor 122, the drain of the first GCNMOS transistor 121 is connected to the ground voltage line 104, the source is the second GCNMOS The drain of the transistor 122 and the input / output data line 102 are connected, and the source of the second GCNMOS transistor 122 is connected to the power supply voltage line 102.

The power clamp unit 130 includes a coupling capacitor 132, an internal resistor 133, and a third GCNMOS transistor 131, and a coupling capacitor 132, an internal resistor 133, and a third GCNMOS transistor 131. ) Is connected to the node 134 and the node 134 is connected to the first GCNMOS transistor 121 and the second GCNMOS transistor 122.

The conventional static electricity protection circuit 100 uses a structure in which the power clamp unit 130 is shared with the CDM transistor unit 120 so that the operation of the CDM transistor unit 120 is prevented by the static electricity introduced by the power clamp unit 130. As a result, the CDM transistor unit 120 has a low operating voltage.

However, since the conventional static electricity protection circuit 100 shares the power clamp unit 130, the pin of the input / output pad 101 is increased by the coupling capacitor 132 so that the capacitor component increases. There was a slowing problem.

In addition, since the operating voltage of the CDM transistor unit 120 is added to the operating voltage of the first diode 111 and the second diode 112 due to the shared structure of the power clamp unit 130, the operation voltage is actually lowered. There was a problem that is not so big.

The present invention provides a low voltage operation type static electricity protection circuit which does not decrease the data transfer rate into the semiconductor device by preventing the capacitor component at the pin from increasing.

In addition, the present invention provides a low voltage operation type static electricity protection circuit suitable for the protection of high speed and highly integrated semiconductor devices having low internal circuit damage voltage by enabling electrostatic discharge at low voltage.

The low voltage operation type static electricity protection circuit of the present invention is connected between a first node and a ground voltage line, and includes a first static electricity induction unit for inducing static electricity when positive static electricity is introduced, and is connected between the first node and a power supply voltage line and is negative. A second static electricity inducing part which induces static electricity when inflow of static electricity, a second node connected to the input / output pad and the ground voltage line, and connected to the first static electricity inducing part and the positive amount of static electricity induced by the first static electricity inducing part A first discharge part turned on to discharge the positive static electricity, a second node connected to an input / output pad, and the power supply voltage line, connected to the second electrostatic induction part, and induced by the second electrostatic induction part The second discharge part and the first node and the second node to turn on the negative static electricity to discharge the negative static electricity It characterized in that it comprises a resistor connected.

Preferably, the first electrostatic induction part is characterized in that it comprises a first diode chain for connecting a plurality of forward diodes in series.

The first electrostatic induction part may further include a first diode in a reverse direction connected in parallel with the first diode chain.

In addition, the second electrostatic induction part is characterized in that it comprises a second diode chain for connecting a plurality of reverse diodes in series.

In addition, preferably, the second electrostatic induction part further comprises a second diode in the forward direction connected in parallel with the second diode chain.

Preferably, the first discharge part may include an NMOS transistor having a gate connected to the first diode chain, and a source and a drain connected between the second node and the ground voltage line, respectively.

Preferably, the second discharge unit may include a PMOS transistor having a gate connected to the second diode chain, and a source and a drain connected between the second node and the power supply voltage line, respectively.

The present invention has the effect of increasing the reliability of the semiconductor device by configuring the capacitor component at the pin not to increase so that the data transfer rate into the semiconductor device is not lowered.

In addition, the present invention can control the operating voltage of the electrostatic discharge portion by the diode chain, thereby enabling electrostatic discharge at low voltage, so that the stability of the semiconductor device by discharge under the low breakdown voltage of the high-speed and highly integrated semiconductor internal circuit There is an effect to increase.

2 is a block diagram of a low voltage operation static electricity protection circuit 200 according to a first embodiment of the present invention, and FIG. 3 is a detailed circuit diagram of a low voltage operation static electricity protection circuit 200 according to a first embodiment of the present invention. to be.

First, referring to FIG. 2, the low voltage operation type static electricity protection circuit 200 of the present invention includes a first electrostatic induction part 210 and a second electrostatic induction part 220, a first electrostatic induction part 210, or a second induction of static electricity. The first discharge unit 230 and the second discharge unit 240 are turned on by the static electricity by the electrostatic induction unit 220 to discharge the static electricity.

The first electrostatic induction unit 210 is connected between the first node 250 and the ground voltage line 204 and induces static electricity from the input / output data line 202 to the ground voltage line 204 when a positive static electricity is introduced.

The second electrostatic induction part 220 is connected between the first node 250 and the power supply voltage line 203 and induces static electricity from the input / output data line 202 to the power supply voltage line 203 when negative static electricity is introduced.

The first discharge part 230 is connected between the second node 260 connected to the input / output pad 201 and the ground voltage line 204, and is connected to the first electrostatic induction part 210, and the first electrostatic induction part 210. Positive static electricity is turned on to discharge positive static electricity.

The second discharge part 240 is connected between the second node 260 connected to the input / output pad 201 and the power voltage line 203, and is connected to the second electrostatic induction part 220, and the second electrostatic induction part 220. It is turned on by negative static electricity induced by to discharge negative static electricity.

In addition, a resistor 270 is connected between the first node 250 and the second node 260.

In this case, the resistor 270 may be configured to have a high resistance value so that the amount of static electricity flowing into the internal circuit 280 does not directly affect the internal circuit 280.

The operation description of the low voltage type static electricity protection circuit 200 according to FIG. 2 is as follows.

When positive static electricity flows into the input / output pad 201, the static electricity flows to the input / output data line 202 and passes through the resistor 270 through the second node 260.

The amount of static electricity passing through the resistor 270 turns on the first discharge unit 230 while passing through the first electrostatic induction unit 210, and the turned on first discharge unit 230 discharges a large amount of static electricity to a ground voltage. Discharge to line 204.

On the contrary, when negative static electricity flows in, the negative static electricity passes through the second node 260 along the input / output data line 202, passes through the resistor 270, and then passes through the second static induction part 220. Turn on (240).

The turned-on second discharge part 240 discharges a large amount of negative static electricity to the power supply voltage line 203, thereby protecting the internal circuit 280.

In this case, since a small amount of positive or negative static electricity flowing into the input / output data line 202 is passed by the resistor 270 having a high resistance value existing between the first node 250 and the second node 260, a small amount is passed. The internal circuit 280 is not directly damaged.

For a detailed description thereof, referring to FIG. 3, the first electrostatic induction part 210 includes a first diode chain 211 connecting a plurality of forward diodes in series.

The first electrostatic induction part 210 includes a first diode 212 in a reverse direction and is connected in parallel with the first diode chain 211.

The second electrostatic induction part 220 includes a second diode chain 221 connecting a plurality of reverse diodes in series.

The second electrostatic induction part 220 connects the second diode 222 in the forward direction with the second diode chain 221 in parallel.

When the first diode chain 211 reaches the operating voltage of the first diode chain 211 when positive static electricity flows, each diode in the forward direction is operated, thereby inducing positive static electricity to the ground voltage line 204. .

At this time, a part of the amount of static electricity that passes the first node 250a (hereinafter referred to as the first node) of the second node 250 is forwarded through the second node 250b (hereinafter referred to as the second node) of the second node 250. 2 is discharged to the power supply voltage line 203 along the second diode 222 of the electrostatic induction part 220.

Meanwhile, when negative static electricity flows through the input / output pad 201 and the second diode chain 221 reaches the operating voltage, each diode in the reverse direction is operated to induce static electricity to the power supply voltage line 203.

In this case, a part of the negative static electricity passing through the first node 250a is discharged to the ground voltage line 204 along the first diode 212 of the first electrostatic induction part 210 in the reverse direction through the second node 250b.

The first discharge unit 230 is composed of the NMOS transistor 231, the gate is connected to the first diode chain 211, the source is connected to the second node 260, the drain is connected to the ground voltage line 204 Connected.

The second discharge part 240 is composed of a PMOS transistor 241, the gate is connected to the second diode chain 221, the source is connected to the power supply voltage line 203, and the drain is connected to the second node 260. Connected.

At this time, in the connection of the gate of the first discharge unit 230 and the first diode chain 211 or the connection of the gate of the second discharge unit 240 and the second diode chain 221, the operating voltage of each diode chain Is designed to be higher than the driving voltage of the semiconductor internal circuit but lower than the gate oxide breakdown voltage of the semiconductor internal circuit.

To this end, the gate of the first discharge unit 230 or the gate of the second discharge unit 240 is connected with the diodes of each diode chain (211, 221) in consideration of the minimum number of diodes that can reach the operating voltage.

Operation of the low voltage type static electricity protection circuit 200 according to FIG. 3 is as follows.

First, when positive static electricity flows into the input / output pad 201, positive static electricity flows through the second node 260, the resistor 270, and the first node 250 along the input / output data line 202.

The first diode chain 211 starts operation when the operating voltage reaches the operating voltage due to positive static electricity, and introduces positive static electricity in the forward direction.

That is, since the first diode chain 211 is composed of four diodes each having a turn-on voltage of 0.7 V, the first diode chain 211 is turned on when the voltage of the first diode chain 211 reaches 2.8 V or more due to positive static electricity.

In this case, the first discharge unit 230 connected to the first diode chain 211 should be designed to have a driving voltage lower than the gate oxide breakdown voltage of the internal circuit 280 so that the gate oxide of the internal circuit 280 is not destroyed. .

3 illustrates that the operating voltage of the NMOS transistor 231 of the first discharge part 230 is designed to be 1.4 V, which is lower than the gate oxide breakdown voltage and higher than the driving voltage of the internal circuit 280.

Accordingly, the NMOS transistor 231 of the first discharge unit 230 has a gate connected between the second and third diodes of each diode of the first diode chain 211, so that when the positive static electricity flows, the first room is 1.4V. All of the NMOS transistors 231 operate.

A large amount of static electricity is discharged through the NMOS transistor 231 of the operated first discharge unit 230, and a portion of the second diode 222 in the second electrostatic induction unit 220 passes through the resistor 270. It discharges to the power supply voltage line 203 through the forward direction or flows to the internal circuit 280.

At this time, a small amount of static electricity flowing into the internal circuit 280 flows only a small amount due to the large resistance value of the resistor 270 does not affect the internal circuit 280.

Meanwhile, when negative static electricity flows into the input / output pad 201, the negative static electricity passes through the second node 260, the resistor 270, and the first node 250 along the input / output data line 202, similarly to the positive static electricity. Flows.

The negative static electricity flows in the reverse direction of the second diode chain 221 when the second diode chain 221 reaches the operating voltage and flows to each diode to operate each diode.

The PMOS transistor 241 of the second discharge unit 240 has a gate connected between the second and third diodes of the second diode chain 221 and is operated at 1.4V when the second diode chain 221 is operated.

The PMOS transistor 241 of the operated second discharge part 240 emits a large amount of negative static electricity, and some negative static electricity passes through the resistor 270 and the first diode 212 in the first electrostatic induction part 210. Is discharged to the ground power line 204 or flows to the internal circuit 280 through the reverse direction.

The influence of negative static electricity flowing through the resistor 270 to the internal circuit 280 is the same as the effect of the positive static electricity introduced into the internal circuit 280 described above.

4 is an operation waveform diagram as a simulation result showing the operating voltage drop of the electrostatic protection element when the present invention is applied.

Referring to FIG. 4, the conventional static electricity protection circuit (100 in FIG. 1) shows an operating voltage of about 5 V in the CDM transistor unit (120 in FIG. 1), while the first discharge unit (FIG. The NMOS transistor (230 of FIG. 3) of FIG. 3 is configured to have a gate connected between the second and third diodes of the first diode chain (211 of FIG. 3) consisting of four diodes, and thus a low operating voltage of about 3 V. Seemed.

As described above, the configuration of the low-voltage operation type electrostatic protection circuit according to the preferred embodiment of the present invention is illustrated with reference to the drawings and described above. However, this is merely an example and is within the scope not departing from the technical spirit of the present invention. Various designs and modifications are possible in the art and it will be readily apparent to those skilled in the art that this is within the scope of the present invention.

1 is a detailed circuit diagram of a conventional static electricity protection circuit.

Figure 2 is a block diagram of a low voltage operation static electricity protection circuit according to an embodiment of the present invention.

3 is a detailed circuit diagram of a low voltage operation type static electricity protection circuit according to the embodiment of the present invention.

4 is a prior art comparative operation waveform diagram of a low voltage operation electrostatic discharge protection circuit according to an embodiment of the present invention;

Claims (7)

A first electrostatic induction part connected between the first node and the ground voltage line and inducing static electricity when positive static electricity is introduced; A second electrostatic induction part connected between the first node and a power supply voltage line and inducing static electricity when negative static electricity is introduced; A second node connected between the second node connected to the input / output pad and the ground voltage line, connected to the first electrostatic induction unit, and turned on by the positive electrostatic charge induced by the first electrostatic induction unit to discharge the positive electrostatic charge; 1 discharge section; A second node connected between the second node connected to the input / output pad and the power voltage line, connected to the second electrostatic induction unit, and turned on by the negative electrostatic induced by the second electrostatic induction unit to discharge the negative electrostatic charge; 2 discharge parts; And A resistor coupled between the first node and the second node; Low voltage operation type static electricity protection circuit comprising a. The method of claim 1, The first electrostatic induction part And a first diode chain for connecting a plurality of forward diodes in series. The method of claim 2 The first electrostatic induction part And a first diode in a reverse direction connecting in parallel with the first diode chain. The method of claim 1 The second electrostatic induction part A low voltage operation type static electricity protection circuit comprising a second diode chain connecting a plurality of reverse diodes in series The method of claim 4, wherein The second electrostatic induction part And a forward second diode connected in parallel with the second diode chain. The method of claim 2, The first discharge unit And an NMOS transistor having a gate connected to the first diode chain, and a source and a drain connected between the second node and the ground voltage line, respectively. The method of claim 4, wherein The second discharge portion And a PMOS transistor having a gate connected to the second diode chain, and a source and a drain connected between the second node and the power supply voltage line, respectively.

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