JP2003174356A - Overvoltage protection circuit, semiconductor device provided with the protection circuit and packaging substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protection circuit having simple constitution and capable of preventing the supply of voltage of a level more than a prescribed value to a function circuit by the simple constitution. <P>SOLUTION: The protection circuit is provided with a switch means connected between a power supply terminal of a succeeding circuit and a ground terminal, and capable of short-circuiting between the power supply terminal and the ground terminal by turning on the switch means itself; and a switch control unit for switching the switch means to ON when the voltage of a level higher than a prescribed value is impressed to the power supply terminal. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overvoltage protection circuit for preventing an overvoltage such as a surge voltage from being applied to a circuit at a subsequent stage, and more particularly to a surge voltage or the like at a circuit at a subsequent stage including a transistor such as a CMOS inverter. The present invention relates to an overvoltage protection circuit for preventing overvoltage from being applied.

[0002]

2. Description of the Related Art A constant voltage Vcc is applied to a power supply terminal of a semiconductor device formed by packaging a semiconductor chip from a constant voltage circuit provided on a substrate on which the semiconductor device is mounted. As is well known, the constant voltage circuit is a circuit that always supplies a constant voltage regardless of what load is applied.

[0003]

However, a surge voltage may be added to the voltage supplied from the constant voltage circuit due to mutual interference between semiconductor devices mounted on the same substrate, an external noise signal, or the like. For example, when a CMOS inverter of a semiconductor chip packaged in a semiconductor device is continuously supplied with a voltage higher than usual,
The latch-up phenomenon occurs, and the output is always fixed at the high level. This causes the semiconductor chip including the CMOS inverter to malfunction. Further, in the case of a CMOS inverter composed of a transistor having a low latch-up resistance, it may be broken.

Therefore, the present invention provides an overvoltage protection circuit, a semiconductor device and a mounting board having the overvoltage protection circuit, which has a simple structure and prevents a voltage of a predetermined level or more from being supplied to a circuit in a subsequent stage. The purpose is to do.

[0005]

A first overvoltage protection circuit according to the present invention is provided between a power supply terminal and a ground terminal of a circuit in a subsequent stage, and is turned on to short-circuit the power supply terminal and the ground terminal. Means and a switch controller for turning on the switch means when a high level voltage of a predetermined value or more is applied to the power supply terminal.

A second overvoltage protection circuit of the present invention is the above-mentioned first overvoltage protection circuit, wherein the switch means is an n-channel MOS transistor having a power supply terminal connected to a drain and a ground terminal connected to a source. The switch control unit divides the voltage applied to the power supply terminal at a predetermined ratio so that the transistor is turned on when a high level voltage of a predetermined value or higher is applied to the power supply terminal. It is a resistance division circuit applied to the gate of the transistor.

A third overvoltage protection circuit of the present invention is the above-mentioned first overvoltage protection circuit, wherein the switch means is a p-channel MOS transistor having a source connected to a power supply terminal and a drain connected to a ground terminal. The switch control unit divides the voltage applied to the power supply terminal at a predetermined ratio so that the transistor is turned on when a high level voltage of a predetermined value or higher is applied to the power supply terminal. It is a resistance division circuit applied to the gate of the transistor.

A fourth overvoltage protection circuit of the present invention is the first overvoltage protection circuit, wherein the switch means is an npn junction transistor having a collector connected to a power supply terminal and an emitter connected to a ground terminal. The switch controller divides the voltage applied to the power supply terminal at a predetermined ratio so that the transistor is turned on when a high level voltage of a predetermined value or more is applied to the power supply terminal. It is characterized in that it is a resistance division circuit applied to the gate of the transistor.

A fifth overvoltage protection circuit of the present invention is the first overvoltage protection circuit, wherein the switch means is a pnp junction transistor having an emitter connected to a power supply terminal and a collector connected to a ground terminal. The switch controller divides the voltage applied to the power supply terminal at a predetermined ratio so that the transistor is turned on when a high level voltage of a predetermined value or more is applied to the power supply terminal. It is characterized in that it is a resistance division circuit applied to the base of the transistor.

The sixth overvoltage protection circuit of the present invention is any one of the above-mentioned second to fifth overvoltage protection circuits, and the resistance division circuit which is the switch control section uses a diode as a load.

A seventh overvoltage protection circuit of the present invention is the above-mentioned first overvoltage protection circuit, wherein the switch means is a one- or multi-stage connection in which a drain is connected to a power supply terminal and a source is connected to a ground terminal. The switch control unit is one diode or a plurality of diodes connected in series, the cathode of the diode located at the end is connected to the power supply terminal, and the opposite end is provided. One or a plurality of series-connected diodes whose anodes are connected to the gate of the n-channel MOS transistor described above or to the gate of the first-stage transistor of the n-channel MOS transistors connected in multiple stages. It is characterized by being composed of a diode.

An eighth overvoltage protection circuit of the present invention is the above-mentioned first overvoltage protection circuit, wherein the switch means is a one- or multi-stage connection in which a source is connected to a power supply terminal and a drain is connected to a ground terminal. The switch controller is a diode or a plurality of diodes connected in series, the anode of the diode located at the end is connected to the ground terminal, and the opposite end is provided. The cathode of the diode located in the section is connected to the gate of the above-mentioned p-channel MOS transistor or the gate of the first-stage transistor of the above-mentioned p-channel MOS transistors connected in multiple stages, or one or a plurality of which are connected in series. It is characterized by being composed of a diode.

A ninth overvoltage protection circuit of the present invention is the above-mentioned first overvoltage protection circuit, wherein the switch means is a one- or multi-stage connection in which a collector is connected to a power supply terminal and an emitter is connected to a ground terminal. Npn junction transistor, wherein the switch controller is one diode or a plurality of diodes connected in series, the cathode of the diode located at the end is connected to the power supply terminal, and the opposite end The anode of the diode located at 1 is connected to the base of the npn junction transistor of 1 above or one of a plurality of diodes connected in series connected to the base of the first stage transistor of the npn junction transistors connected in multiple stages. It is characterized by being configured.

A tenth overvoltage protection circuit of the present invention is the first overvoltage protection circuit, wherein the switch means is
It is a pnp junction transistor having a power supply terminal connected to an emitter and a ground terminal connected to a collector, and the switch control unit is one diode or a plurality of diodes connected in series, The anode of the diode located in the section is connected to the ground terminal,
The cathode of the diode located at the opposite end is 1 above.
Of the pnp junction transistor, or one of a plurality of diodes connected in series, which is connected to the base of the first-stage transistor of the multistage-connected pnp junction transistors.

The semiconductor device of the present invention is characterized by including any of the above-mentioned overvoltage protection circuits.

The mounting board of the present invention is characterized in that any of the above-mentioned overvoltage protection circuits is provided on the board.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION (1) Outline of the Invention An overvoltage protection circuit of the present invention is provided, for example, between a power supply terminal and a ground terminal of a drive power supply Vcc of a circuit in the subsequent stage including a transistor, and is turned on to turn on the above. A switch means for short-circuiting the power supply terminal and the ground terminal; and a switch control section for turning on the switch means when a high level voltage exceeding a predetermined value that may malfunction or destroy the circuit at the subsequent stage is applied. It is characterized by including.

By adopting the above structure, it is possible to reduce the influence of the surge voltage with a simple structure. Embodiments 1 to 5 of the overvoltage protection circuit will be described below with reference to the accompanying drawings.

(2) First Embodiment FIG. 1 is a diagram showing a configuration of an overvoltage protection circuit 4 according to the first embodiment. The overvoltage protection circuit 4 is provided in the semiconductor device 100.
Built into. To be more precise, the overvoltage protection circuit 4 is provided in the semiconductor chip included in the semiconductor device 100. The overvoltage protection circuit 4 is provided between the power supply terminal 5 and the ground terminal 6 of the functional circuit 50. The functional circuit 50 is a CMO.
It is composed of a large number of logic gates such as an S inverter, processes a data signal input to the terminal 8 from the outside, and outputs the processed data from the terminal 9 to the circuit 200 in the subsequent stage. Circuit 2
00 includes a switching element such as an IGBT.

The overvoltage protection circuit 4 is provided between the power supply terminal 5 and the ground terminal 6 of the functional circuit 50, and serves as a switch means for short-circuiting the power supply terminal 5 and the ground terminal 6 by switching on. An n-channel MOS transistor 1 having a drain connected to 5 and a source connected to the ground terminal 6 is provided.

Further, the overvoltage protection circuit 4 includes a functional circuit 50.
As a switch control unit for switching on the transistor 1 which is the switch means when a high level voltage exceeding a predetermined value that may cause malfunction or damage is applied, a resistor 2 is provided between the power supply terminal 5 and the ground terminal 6. A resistor divider circuit 7 is formed by connecting resistors 3 in series, and a midpoint P1 between the resistors 2 and 3 is connected to the gate of the transistor 1.

Incidentally, the resistors 2 and 3 of the resistor division circuit 7
Is a value of the transistor 1 when a high level voltage that may cause malfunction or damage of the functional circuit 50 in the subsequent stage is applied.
Set to apply to the gate a voltage that turns on.

[0023] For example, a power supply voltage Vcc is 15v, when the threshold voltage _{V TH} of the gate of n-channel MOS transistor 1 is 1.0 v, and sets the resistance 2 in 39Keiomega, setting the resistance 3 to 1KΩ .

In the structure, the voltage applied to the functional circuit 50 by the surge voltage is 40V in the transistor 1.
When it exceeds, it is switched on and the power supply terminal 5 and the ground terminal 6 are short-circuited. As a result, a surge voltage larger than 40 V is continuously applied to the functional circuit 50 and the functional circuit 5
Prevent 0 from breaking.

The overvoltage protection circuit 4 is used in the semiconductor device 1
However, the present invention is not limited to this, and a conventional semiconductor chip not including the overvoltage protection circuit 4 may be provided on a lead frame for wire bonding. Thereby, further versatility can be secured. In addition, a semiconductor device having a single overvoltage protection circuit may be prepared, or may be provided between a power supply terminal and a ground terminal on a substrate on which a plurality of semiconductor devices are mounted. The semiconductor devices 110 and 12 of the second to fifth embodiments described below
The same applies to 0, 130 and 140.

(3) Second Embodiment FIG. 2 is a diagram showing a configuration of an overvoltage protection circuit 10 according to the second embodiment. The configuration of the semiconductor device 110 is the same as that of the semiconductor device 100 shown in FIG. 1 in which the overvoltage protection circuit 4 is replaced with the overvoltage protection circuit 10, and the same components are denoted by the same reference numerals. The duplicate explanation is omitted.

The overvoltage protection circuit 10 includes an overvoltage protection circuit 4
The same function as the above is realized by using a p-channel MOS transistor. Specifically, the overvoltage protection circuit 10
Is provided between the power supply terminal 5 and the ground terminal 6 of the functional circuit 50, and a source is connected to the power supply terminal 5 as a switch means for short-circuiting the power supply terminal 5 and the ground terminal 6 by switching on. A p-channel MOS transistor 11 having a drain connected to the ground terminal 6 is provided.

Further, the overvoltage protection circuit 10 includes a functional circuit 5
As a switch control unit for switching on the transistor 11 which is the switch means when a voltage of a high level exceeding 0, which may cause malfunction or breakage, is applied, a resistor 12 is provided between the power supply terminal 5 and the ground terminal 6. And resistance 1
3 is connected in series, and the resistance division circuit 14 is provided in which the midpoint P2 of the resistance 12 and the resistance 13 is connected to the gate of the transistor 1.

Note that the values of the resistors 12 and 13 of the resistance division circuit 14 are such that the transistor 11 turns on when a high level voltage is applied which causes the functional circuit 50 in the subsequent stage to malfunction. Is set to be applied to.

[0030] For example, a power supply voltage Vcc is 15v, when the threshold voltage _{V TH} of the gate of the p-channel MOS transistor 11 is -1.0 V, the resistance 12 1K
Ω and the resistor 13 to 39 KΩ.

In this structure, the transistor 11 is
The voltage applied to the functional circuit 50 by the surge voltage is 40
When it exceeds v, it is switched on and the power supply terminal 5 and the ground terminal 6 are short-circuited. This prevents the surge voltage larger than 40 V from being continuously applied to the functional circuit 50 and damaging the functional circuit 50.

(4) Third Embodiment FIG. 3 is a diagram showing the configuration of the overvoltage protection circuit 20 according to the third embodiment. The configuration of the semiconductor device 120 is the same as that of the semiconductor device 100 shown in FIG. 1 in which the overvoltage protection circuit 4 is replaced with the overvoltage protection circuit 20, and the same components are denoted by the same reference numerals. The duplicate explanation is omitted.

The overvoltage protection circuit 20 includes an overvoltage protection circuit 4
The same function as the above is realized by a bipolar transistor having an npn junction. Specifically, the overvoltage protection circuit 2
0 is provided between the power supply terminal 5 and the ground terminal 6 of the functional circuit 50, and a collector is connected to the power supply terminal 5 as a switch means for short-circuiting the power supply terminal 5 and the ground terminal 6 by switching on. And an npn junction transistor 21 having an emitter connected to the ground terminal 6.

Further, the overvoltage protection circuit 20 includes the functional circuit 5
As a switch control unit that turns on the transistor 21 that is the switching means when a high level voltage exceeding a predetermined value that may cause malfunction or damage is applied.
The resistor 22 and the resistor 23 are connected in series between the power supply terminal 5 and the ground terminal 6, and the intermediate point P3 of the resistor 22 and the resistor 23 is formed.
Includes a resistance divider circuit 24 connected to the base of the transistor 21.

The values of the resistors 22 and 23 of the resistance division circuit 24 are based on the voltage at which the transistor 21 is turned on when a high level voltage is applied which causes the functional circuit 50 in the subsequent stage to malfunction. Is set to be applied to.

For example, when the power supply voltage Vcc is 15 v and the threshold voltage V _BE of the base of the npn junction transistor 21 is 0.7 v, the resistor 22 is set to 39.3 KΩ and the resistor 23 is 0.7 KΩ. Set to.

In this structure, the transistor 21 is
The voltage applied to the functional circuit 50 by the surge voltage is 40
When it exceeds v, it is switched on and the power supply terminal 5 and the ground terminal 6 are short-circuited. This prevents a surge voltage larger than 40 V from being continuously applied to the functional circuit 50 and causing the functional circuit 50 to collapse.

Note that instead of the npn junction transistor 21, a pnp junction transistor may be used to form a protection circuit having the same function.

(5) Fourth Embodiment FIG. 4 is a diagram showing the structure of the overvoltage protection circuit 30 according to the fourth embodiment. The configuration of the semiconductor device 130 is the same as that of the semiconductor device 100 shown in FIG. 1 in which the overvoltage protection circuit 4 is replaced with the overvoltage protection circuit 30, and the same components are denoted by the same reference numerals. The duplicate explanation is omitted.

The protection circuit 30 includes n pin diodes Z1, Z2 ... Zn which are reverse-connected in series so that a reverse bias is applied, instead of the resistor 2 provided in the resistance division circuit 7 of the overvoltage protection circuit 4. It is characterized in that it is used as the load 32. Each of the pin diodes Z1, Z2 ... Zn causes Zener collapse when a predetermined voltage is applied, and causes a current to flow to the next stage.

More specifically, the overvoltage protection circuit 30 is provided between the power supply terminal 5 and the ground terminal 6 of the functional circuit 50.
An n-channel MOS transistor 31 having a source connected to the power supply terminal 5 and a drain connected to the ground terminal 6 is provided as switch means for short-circuiting the power supply terminal 5 and the ground terminal 6 by switching on.

Further, the overvoltage protection circuit 30 includes the functional circuit 5
As a switch control unit for turning on the transistor 31 which is the switch means when a high level voltage exceeding a predetermined value that causes malfunction or destruction of 0 is applied, the load 32 is connected between the power supply terminal 5 and the ground terminal 6. And resistance 3
3 is connected in series, and includes a resistance dividing circuit 34 in which the intermediate point P4 of the load 32 and the resistor 33 is connected to the gate of the transistor 31.

The values of the load 32 and the resistor 33 of the resistance dividing circuit 34 are applied to the gate so that the transistor 31 is turned on when a high level voltage is applied which causes the functional circuit 50 in the subsequent stage to malfunction. Set to do.

[0044] For example, a power supply voltage Vcc is 15v, when the threshold voltage _{V TH} of the gate of n-channel MOS transistor 31 is 1.0 v, have configured the Zener voltage Vz of the load 32 to 40v, resistance 33 to 1.0
Set to KΩ.

In this structure, the transistor 31 is
The voltage applied to the functional circuit 50 by the surge voltage is 40
When it exceeds v, it is switched on and the power supply terminal 5 and the ground terminal 6 are short-circuited. This prevents the surge voltage larger than 40 V from being continuously applied to the functional circuit 50 and damaging the functional circuit 50.

In the overvoltage protection circuit 30, the load 32
This has the advantage that the current is not consumed in the resistance division circuit 34 until it becomes conductive.

In place of the n-channel MOS transistor 31 of the overvoltage protection circuit 30, a p-channel MO transistor is used.
Any of an S transistor, an npn junction transistor, and a pnp junction transistor may be used.

However, a p-channel MOS transistor,
And when using a pnp junction transistor, load 3
2 and the arrangement of the resistor 33 must be changed and their values must be changed appropriately. More specifically, the anode of the diode Z1 forming the load 32 is connected to the ground terminal 6, and the cathode of the diode Zn is connected to the gate or base of the transistor. Further, one end of the resistor 33 is connected to the power supply terminal 5, and the other end is connected to the gate or base of the transistor.

(6) Fifth Embodiment FIG. 5 shows the fifth embodiment.
It is a figure which shows the structure of the overvoltage protection circuit 40 which concerns on. The configuration of the semiconductor device 140 is the same as the semiconductor device 100 shown in FIG.
The same components as those in which the overvoltage protection circuit 4 is replaced with the overvoltage protection circuit 40, and the same components are denoted by the same reference numerals, and a duplicate description thereof will be omitted.

The overvoltage protection circuit 40 is provided between the power supply terminal 5 and the ground terminal 6 of the functional circuit 50, and has two stages as a switch means for short-circuiting the power supply terminal 5 and the ground terminal 6 by switching on. And npn junction transistors 41 and 42 connected to each other (Darlington connection). In addition,
In the overvoltage protection circuit 40, the npn junction transistor connected in two stages (Darlington connection) is adopted as the final stage transistor (corresponding to the transistor 41 in this example).
Is to improve the flow of current when the power supply terminal 5 and the ground terminal 6 are short-circuited, and similarly, the number of connections may be increased to three or four.

Further, the overvoltage protection circuit 40 includes the functional circuit 5
As a switch control unit that turns on the transistors 41 and 42 that are the above-mentioned switch means when a voltage of a high level exceeding 0 that malfunctions or is destroyed is applied, a reverse bias is applied in the reverse direction. A plurality of pin diodes 43 to 47 connected in series to
The diode 43 has a cathode connected to the power supply terminal 5, and an anode of the diode 47 at the opposite end connected to the base of the transistor 42.

Now, assuming that the total of the Zener voltages of the five diodes 43 to 47 is Vz, when the voltage Vcc applied to the power supply terminal 5 exceeds Vz, Zener collapse occurs and a current flows to the base of the transistor 42. Begins to flow. In response to this, the transistors 42 and 41 are continuously turned on,
The transistor 41 short-circuits the power supply terminal 5 and the ground terminal 6.

[0053] For example, the power supply voltage Vcc is a 15v, when the base of the threshold voltage _{V BE} of the npn junction transistor 42 is 0.7 v, 5 diodes 43-4
The total of the Zener voltage of 7 is set to Vz = 40V.

In this structure, the transistor 42 is
The voltage applied to the functional circuit 50 by the surge voltage is 40
When it exceeds v, it is switched on and the power supply terminal 5 and the ground terminal 6 are short-circuited. This prevents a surge voltage larger than 40 V from being continuously applied to the functional circuit 50 and causing the functional circuit 50 to collapse.

In place of the npn junction transistors 41 and 42 of the overvoltage protection circuit 40, an n-channel MOS transistor and a p-channel M connected in two stages respectively.
Either an OS transistor or a pnp junction transistor may be used.

However, pnp junction transistor and p
When using a channel MOS transistor, the arrangement of the load circuit composed of the diodes 43 to 47 connected in series is changed. Specifically, the cathode of the diode 43 of the load circuit is connected to the base or gate of the first-stage transistor, and the anode of the diode 47 is connected to the ground terminal 5.
Connect to.

[0057]

The first overvoltage protection circuit of the present invention short-circuits the power supply terminal and the ground terminal of the protected circuit when a high level voltage exceeding a predetermined value is applied to the protected circuit in the subsequent stage. , The high level voltage is applied to the protected circuit,
Prevent circuits from malfunctioning or breaking.

In the second overvoltage protection circuit of the present invention, when a high level voltage exceeding a predetermined value is applied to the circuit to be protected in the subsequent stage, the n-channel MOS transistor which is the switch means is turned on and the circuit to be protected is turned on. The power supply terminal and the ground terminal are short-circuited to prevent the above-mentioned high level voltage from being applied to the protected circuit, thereby preventing the circuit from malfunctioning or breaking.

In the third overvoltage protection circuit of the present invention, when a high level voltage exceeding a predetermined value is applied to the circuit to be protected in the subsequent stage, the p-channel MOS transistor which is the switching means is turned on and the circuit to be protected is turned on. The power supply terminal and the ground terminal are short-circuited to prevent the above-mentioned high level voltage from being applied to the protected circuit, thereby preventing the circuit from malfunctioning or breaking.

In the fourth overvoltage protection circuit of the present invention, when a high level voltage exceeding a predetermined value is applied to the protected circuit in the subsequent stage, the npn junction transistor which is the switch means is turned on, and the power supply of the protected circuit is turned on. A short circuit is made between the terminal and the ground terminal to prevent the above-mentioned high level voltage from being applied to the protected circuit and prevent the circuit from malfunctioning or breaking.

In the fifth overvoltage protection circuit of the present invention, when a high level voltage exceeding a predetermined value is applied to the circuit to be protected in the subsequent stage, the pnp junction transistor which is the switch means is turned on, and the power supply of the circuit to be protected is turned on. A short circuit is made between the terminal and the ground terminal to prevent the above-mentioned high level voltage from being applied to the protected circuit and prevent the circuit from malfunctioning or breaking.

The sixth overvoltage protection circuit of the present invention utilizes the voltage resistance characteristic of the reversely connected diode to short-circuit between the power supply terminal and the ground terminal of the protected circuit, and to protect the protected circuit from the high level. Voltage is applied to prevent the circuit from malfunctioning or breaking. Moreover, since no operation is performed until the voltage of the above-mentioned large level is applied, there is no waste of power consumption and it is economical.

A seventh overvoltage protection circuit of the present invention is a switch control unit, which is a diode connected in a predetermined number in series, in which a cathode at an end is connected to a power supply terminal and an anode at the remaining end is connected. Is connected to the gate of an n-channel MOS transistor. This allows
A high level voltage can be applied to the protected circuit to prevent the circuit from malfunctioning or breaking. In addition, the circuit does not operate at all until a high level voltage is applied, which is economical without wasteful consumption of electric power.

The eighth overvoltage protection circuit of the present invention is a switch control unit, which is a diode connected in a predetermined number in series, in which the anode of the end is connected to the ground terminal and the cathode of the remaining end is connected. Is connected to the gate of a p-channel MOS transistor. This allows
A high level voltage can be applied to the protected circuit to prevent the circuit from malfunctioning or breaking. In addition, the circuit does not operate at all until a high level voltage is applied, which is economical without wasteful consumption of electric power.

The ninth overvoltage protection circuit of the present invention is a switch control section, which is a diode connected in a predetermined number in series, in which the cathode of the end is connected to the power supply terminal and the anode of the remaining end is connected. Is connected to the base of an npn junction transistor. As a result, a high level voltage is applied to the protected circuit, and it is possible to prevent the circuit from malfunctioning or breaking. In addition, the circuit does not operate at all until a high level voltage is applied, which is economical without wasteful consumption of electric power.

A tenth overvoltage protection circuit of the present invention is a switch control section, which is a diode connected in a predetermined number in series, in which an anode at an end is connected to a ground terminal and a cathode at the remaining end is connected. Is connected to the base of a pnp junction transistor. As a result, a high level voltage is applied to the protected circuit, and it is possible to prevent the circuit from malfunctioning or breaking. In addition, the circuit does not operate at all until a high level voltage is applied, which is economical without wasteful consumption of electric power.

The semiconductor device of the present invention can be distributed as a semiconductor device having high resistance to overvoltage by incorporating any of the above-mentioned overvoltage protection circuits.

The mounting board of the present invention can be distributed as a mounting board having a function of protecting a semiconductor device mounted from an overvoltage by including any one of the overvoltage protection circuits described above.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a semiconductor integrated circuit including a protection circuit according to a first embodiment.

FIG. 2 is a diagram showing a configuration of a semiconductor integrated circuit including a protection circuit according to a second embodiment.

FIG. 3 is a diagram showing a configuration of a semiconductor integrated circuit including a protection circuit according to a third embodiment.

FIG. 4 is a diagram showing a configuration of a semiconductor main circuit including a protection circuit according to a fourth embodiment.

FIG. 5 is a diagram showing a configuration of a semiconductor integrated circuit including a protection circuit according to a fifth embodiment.

[Explanation of symbols]

1,31 n-channel MOS transistor, 2,3
12, 13, 22, 23, 33 Resistance, 4, 10, 2
0, 30, 40 Overvoltage protection circuit, 5 power supply terminals, 6
Ground terminal, 8 data input terminals, 9 data output terminals,
11 p-channel MOS transistors 21, 41,
42 npn junction transistor, 43-47, Z1-Z
n Zener diode, 50 functional circuit.

Claims (12)

[Claims] 1. A switch means which is provided between a power supply terminal and a ground terminal of a circuit in a subsequent stage and short-circuits between the power supply terminal and the ground terminal when turned on, and a high level voltage of a predetermined value or more at the power supply terminal. An overvoltage protection circuit, comprising: a switch control unit that turns on the switch means when a voltage is applied. 2. The overvoltage protection circuit according to claim 1, wherein the switch means has a drain connected to a power supply terminal,
An n-channel MOS transistor having a source connected to a ground terminal, wherein the switch control unit controls the power supply terminal so that the transistor is turned on when a high level voltage higher than a predetermined value is applied to the power supply terminal. An overvoltage protection circuit, wherein the overvoltage protection circuit is a resistance divider circuit that divides a voltage applied to the transistor at a predetermined ratio and applies the divided voltage to the gate of the transistor. 3. The overvoltage protection circuit according to claim 1, wherein the switch means is a p-channel MOS transistor having a source connected to a power supply terminal and a drain connected to a ground terminal, and the switch control unit. Applies the voltage applied to the power supply terminal to the gate of the transistor in a predetermined ratio so that the transistor is turned on when a high level voltage of a predetermined value or more is applied to the power supply terminal. An overvoltage protection circuit characterized by being a resistance division circuit. 4. The overvoltage protection circuit according to claim 1, wherein the switch means has a collector connected to a power supply terminal,
An npn junction transistor having an emitter connected to a ground terminal, wherein the switch control unit connects to the power supply terminal so that the transistor is turned on when a high level voltage of a predetermined value or more is applied to the power supply terminal. An overvoltage protection circuit, which is a resistance division circuit that divides an applied voltage at a predetermined ratio and applies the divided voltage to the base of the transistor. 5. The overvoltage protection circuit according to claim 1, wherein the switch means has an emitter connected to a power supply terminal,
A pnp junction transistor having a collector connected to a ground terminal, wherein the switch control unit applies power to the power supply terminal so that the transistor is turned on when a high level voltage of a predetermined value or higher is applied to the power supply terminal. An overvoltage protection circuit, which is a resistance division circuit that divides an applied voltage at a predetermined ratio and applies the divided voltage to the base of the transistor. 6. The overvoltage protection circuit according to claim 2, wherein the resistance division circuit, which is a switch control unit, uses a diode as a load. circuit. 7. The overvoltage protection circuit according to claim 1, wherein the switch means has a drain connected to a power supply terminal,
Source connected to ground terminal or n connected in multiple stages
A channel MOS transistor, wherein the switch control unit is one diode or a plurality of diodes connected in series, the cathode of the diode located at the end is connected to the power supply terminal, and the switch control unit is located at the opposite end. The anode of the diode is composed of one or a plurality of diodes connected in series whose gate is connected to the gate of the n-channel MOS transistor described above or the gate of the first-stage transistor among the n-channel MOS transistors connected in multiple stages. An overvoltage protection circuit characterized by being provided. 8. The overvoltage protection circuit according to claim 1, wherein the switch means has one or more p-stages in which a source is connected to a power supply terminal and a drain is connected to a ground terminal.
A channel MOS transistor, wherein the switch control unit is one diode or a plurality of diodes connected in series, the anode of the diode located at the end is connected to the ground terminal, and the switch control unit is located at the opposite end. The diode has a cathode connected to the gate of the p-channel MOS transistor described above or to the gate of the first-stage transistor of the p-channel MOS transistors connected in multiple stages, or a plurality of diodes connected in series. An overvoltage protection circuit characterized by being configured. 9. The overvoltage protection circuit according to claim 1, wherein the switch means has a collector connected to a power supply terminal,
The switch control unit is one diode or a plurality of diodes connected in series, wherein the cathode of the diode located at the end is The anode of the diode, which is connected to the power supply terminal and is located at the opposite end, is the base of the npn junction transistor described in 1 above, or the n connected in multiple stages.
An overvoltage protection circuit comprising one or a plurality of diodes connected in series connected to the base of a first-stage transistor of the pn junction transistors. 10. The overvoltage protection circuit according to claim 1, wherein the switch means has an emitter connected to a power supply terminal,
It is a pnp junction transistor in which a collector is connected to a ground terminal or is connected in multiple stages, and the switch control unit is one diode or a plurality of diodes connected in series, and the anode of the diode located at the end is The cathode of the diode connected to the ground terminal and located at the opposite end is the base of the pnp junction transistor described in 1 above, or the p connected in multiple stages.
An overvoltage protection circuit comprising one or a plurality of diodes connected in series connected to the base of a first-stage transistor of the np junction transistors. 11. A semiconductor device comprising the overvoltage protection circuit according to any one of claims 1 to 10. 12. A mounting board comprising the overvoltage protection circuit according to claim 1 on a board.