JPH08250645A - Semiconductor device and amplifying circuit - Google Patents

Abstract

PURPOSE: To provide a semiconductor device and a buffer circuit wherein the space and the cost are reduced by reducing the number of components. CONSTITUTION: Only when an input voltage is higher than the divided voltage VA determined by resistors 4c, 6 in a semiconductor device 4, an input signal is amplified by a common emitter amplifier constituted of resistors 1, 3 and a transistor 2, and further amplified by the next stage common emitter amplifier constituted of resistors 7, 9 and a transistor 8. When the input is lower than VA, the transistors 2, 8 are turned into the state of cutoff, and the output becomes equal to the earth potential.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device in which a plurality of resistors and diodes are integrated into one chip, and an amplifier circuit to which the semiconductor device is applied.

[0002]

2. Description of the Related Art It is a well-known fact that semiconductor devices have been highly integrated in recent years. On the other hand, when connecting these highly integrated circuits, it is a fact that they are still connected by discrete components via resistors and diodes. The reason for this is that if you connect while leaving the difference in the power supply voltage or the difference in the ground potential, it will be highly integrated,
This is because the withstand voltage and withstand current of the input section are reduced, and the expensive highly integrated circuit itself may be destroyed.

[0003]

However, when a protection circuit or the like using such discrete components is used, the number of components is inevitably increased, and the area of the board on which the components are mounted has many landmarks. Needed or
Since it is necessary to separate the landmarks by a predetermined width so that they do not come into contact with each other during etching, the landmarks become large, and there is a problem that they become an obstacle to high cost and miniaturization.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a semiconductor device and a buffer circuit aiming at space saving and cost reduction by reducing the number of parts.

[0005]

In order to achieve the above object, a semiconductor device of the present invention comprises a diode and first and second resistors connected in series to a first electrode of the diode. A first terminal connected to a connection point between the first resistor and the second resistor, a second terminal connected to the other end of the second resistor, and a second electrode of the diode A third terminal is provided, and the diode and the first terminal are provided.
And the second resistor in one molded package.

Also, in the amplifier circuit of the present invention, the first terminal is connected to a power source through a third resistor, the second terminal is connected to a reference potential point, and the third terminal is a grounded-emitter type. It is connected to the emitter of the amplifier.

[0007]

With the above structure, the semiconductor device according to the present invention comprises the diode and the first and second resistors connected in series to the first electrode of the diode. A first terminal connected to the connection point of the second resistor, a second terminal connected to the other end of the second resistor, and a third terminal connected to the second electrode of the diode are provided, and the diode and the By housing the first and second resistors in one mold package, the number of parts can be reduced, and as a result, space saving and cost reduction can be achieved.

With the above structure, in the amplifier circuit according to the second aspect, the first terminal is connected to the power source through the third resistor, the second terminal is connected to the reference potential point, and the third terminal is connected. Is connected to the emitter of the grounded-emitter amplifier, the number of parts is reduced, and as a result, space saving and cost reduction are aimed at.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. 1 is a circuit diagram of a semiconductor device and an amplifier circuit to which the semiconductor device is applied according to an embodiment of the present invention. In FIG. 1, 1, 3, 6, 7, and 9 are resistors, 2 is an NPN transistor, 5 is a capacitor, 8 is a PNP transistor, and 4 is a semiconductor device of the present application.
The operation of the semiconductor device of the present invention configured as described above and the amplifier circuit to which the semiconductor device is applied will be described below.

The input signal is input to the base terminal of the transistor 2 and is amplified by (R2 / R1) times, where R1 is the resistance value of the resistor 3 and R2 is the resistance value of the resistor 1. It Here, when the resistance value of the resistor 4c in the semiconductor device 4 is R3 and the resistance value of the resistor 6 is R4, the potential VA at the point A in the figure is given by the following equation.

[0011]

[Equation 1]

This potential VA is supplied to the emitter of the transistor 2 from the diode 4a via the resistor 4b. Here, since the operating voltage in the forward direction of the diode and the operating voltage between the base and emitter of the transistor 2 are almost the same, the transistor 2 is cut off if the potential at the point A on the figure and the input voltage are the same or higher. Will be turned off.
Therefore, the amplifier circuit of FIG. 1 has a structure that does not work when the input is not more than VA of the above formula (1). The capacitor 5 is just a decap.

When the voltage is higher than VA, the output of the grounded-emitter amplifier composed of resistors 1 and 3 and transistor 2 is the grounded-emitter amplifier composed of resistors 7 and 9 and transistor 8 in the next stage. Will be further amplified and output at. Here, if the resistance value of the resistor 7 is R7 and the resistance value of the resistor 9 is R9, the amplification factor of the circuit of FIG. 1 is (R2 / R1) · (R7 / R9). On the contrary, when the input is equal to or lower than the voltage VA, the transistor 2 is cut off, so that the transistor 8 is also cut off and the output becomes the ground potential.

Here, the semiconductor device 4 is one element coated with a one-chip mold resin, and is incorporated in the package in the arrangement as shown in FIG. Therefore, the number of elements in the circuit of FIG. 1 is nine in total, which is two compared with the case where the semiconductor device 4 is composed of separate elements. Further, when the semiconductor element 4 is mounted on the printed circuit board, the number of terminals is three, so that it is possible to reduce three landmarks considering that the number of terminals is six when the different elements are combined. become.

In the above embodiment, the semiconductor device as shown in FIG. 2A was used, but for other circuits, for example, the diode direction is reversed as shown in FIG. 2B. Good. The semiconductor device of FIG. 2 may be used not only in the analog amplifier circuit as described above,
For example, it may be used for connection between integrated circuits as described in the section of the prior art. In addition, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made.

[0016]

As described above, according to the present invention, claim 1
In the semiconductor device of 1), the diode and the first and second resistors connected in series to the first electrode of the diode are provided, and the first resistor connected to the connection point of the first resistor and the second resistor. One terminal, a second terminal connected to the other end of the second resistor, and a third terminal connected to the second electrode of the diode are provided, and the diode and the first and second resistors are formed in one mold. -By putting it in a package, the number of parts can be reduced, and as a result, space saving and cost reduction can be achieved.

Furthermore, there is an effect that the transmission speed can be improved by reducing the circuit area. Further, since the number of wirings between adjacent electronic components on the substrate can be reduced, noise is less picked up, and there is an effect that high performance can be achieved. Further, since the number of electronic components mounted on the board is reduced, it is possible to reduce the number of mounting defects.

Further, in the amplifier circuit according to claim 2, the first circuit is provided.
Since the terminal is connected to the power source through the third resistor, the second terminal is connected to the reference potential point, and the third terminal is connected to the emitter of the grounded-emitter amplifier, the number of parts is reduced, As a result, there is an effect that space saving and cost reduction can be aimed at.

Furthermore, there is an effect that the transmission speed can be improved by reducing the circuit area. Further, since the number of wirings between adjacent electronic components on the substrate can be reduced, noise is less picked up, and there is an effect that high performance can be achieved. Further, since the number of electronic components mounted on the board is reduced, it is possible to reduce the number of mounting defects.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an amplifier circuit to which a semiconductor device according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing another configuration example of the semiconductor device in the example.

[Explanation of symbols]

 1, 3, 6, 7, 9 Resistor 2 NPN transistor 4 Semiconductor device 5 Capacitor 8 PNP transistor

Claims (2)

[Claims] 1. A diode, a first electrode connected in series to a first electrode of the diode,
A second resistor; and the first resistor and the second resistor
A first terminal connected to the connection point of the resistor, a second terminal connected to the other end of the second resistor, and a third terminal connected to the second electrode of the diode, and the diode and the third terminal. A semiconductor device in which the first and second resistors are housed in a single molded package. 2. The first terminal is connected to a power source through a third resistor, the second terminal is connected to a reference potential point, and the third terminal is connected to the emitter of a grounded-emitter amplifier. Amplifier circuit consisting of.