JPH023322B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resistance value setting circuit, and particularly to increasing the resistance value in a semiconductor integrated circuit.

Conventionally, in semiconductor integrated circuits, in order to increase the output voltage of an amplifier circuit or a rectifier circuit, methods have been adopted such as increasing the circuit current or increasing the value of a monolithic resistor.

However, increasing the circuit current
Although high output is possible with a small resistance, current loss cannot be ignored. Furthermore, setting a large monolithic resistor on a semiconductor integrated circuit requires forming it in a separate process due to the internal resistance of the semiconductor integrated circuit itself, and increases the chip area by increasing the resistor area. There are drawbacks such as.

An object of the present invention is to provide a resistance value setting circuit that increases the resistance value using circuit means and forms a large equivalent resistance.

The present invention is characterized in that a resistor is connected between the emitter of the transistor and the input part of the current inversion circuit, and the output part of the current inversion circuit is connected to the base of the transistor.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

FIG. 1 shows an embodiment of the resistance value setting circuit of the present invention. In the figure, a power supply terminal 4 is formed at the collector of a transistor 2.
A drive voltage Vcc is applied between the common terminal 6 and the common terminal 6. Emitter of transistor 2 and current inversion circuit 8
A reference resistor 10 is connected between the input section and the input section. The current inverting circuit 8 has a transistor 12 configured as a diode with a common base and collector connected in the forward direction between the base and emitter of a transistor 14.
The common terminal 6 is formed on the emitters 2 and 14. The base of the transistor 2 is connected to the collector of the transistor 14, and an output terminal 16 is formed.

According to such a configuration, the value of the resistor 10 is Rx,
The emitter area of transistors 12 and 14 is Q _A ,
Assuming Q _B , the equivalent resistance value Ry between the output terminal 16 and the common terminal 6 is given by the relationship with the current I flowing from the emitter of the transistor 2 to the resistor 10, Ry=Rx (Q _A /Q _B )... (1) becomes. That is, the emitter area of transistor 12
By arbitrarily setting the ratio between Q _A and the emitter area Q _B of the transistor 14, the equivalent resistance Ry
can be set to a desired value.

According to such a resistance value setting circuit, an arbitrary high resistance can be achieved by changing the ratio of the emitter areas of the transistors 12 and 14, and no special process such as an ion implantation process is required. High resistance can be achieved at a low price,
It is possible to improve the economy of the chip area of a semiconductor integrated circuit.

FIG. 2 shows a rectifier circuit which is an application example of the present invention, and parts common to the embodiment shown in FIG. 1 are given the same reference numerals. In the figure, a differential amplifier 18 is installed in this rectifier circuit, and this differential amplifier 18 includes a pair of transistors 2 having a common emitter.
0 and 22 are installed. An input terminal 24 is formed at the base of the transistor 20 to which an AC input to be rectified is applied. A constant bias is applied to a bias input terminal 26 formed in the transistor 22 from a bias circuit (not shown). The operating current of the differential amplifier 18 is supplied by a constant current source 28
The constant current of the constant current source 28 is configured to cause an operating current to flow through the transistors 20 and 22 via a current inversion circuit consisting of transistors 30 and 32.

Further, the collector of the transistor 22 is connected to the power supply line, and a transistor 34 having a common base and collector is connected between the collector of the transistor 20 and the power supply line, and the differential amplifier 1
The output of 8 is taken from the collector of transistor 20 and applied to the base of transistor 36. The collector of the transistor 36 is commonly connected to the collector of the transistor 38 forming a current inverting circuit with the transistor 30, and these transistors 36 and 38 are connected in series between the power supply line and the common line.

The half-wave rectified output is the transistor 36, 3
8 and is taken out from the collector of resistance value setting circuit 4.
0 to the base of transistor 2.
Output transistor 4 is connected to the base of transistor 2.
2, the collector of this transistor 42 is connected to the power supply line, and the emitter is connected to an output terminal 46 via a diode 44.
is formed. A capacitor 4 constituting a smoothing circuit is connected between this output terminal 46 and the common line.
8 and a resistor 50 are connected.

In a rectifier circuit using such a resistance value setting circuit 40 as a load resistor, the input voltage V _IN applied to the input terminal 24, the constant current given by the constant current source 28 I, and the ratio of the emitter areas of the transistors 30 and 32. is doubled, the operating current flowing through the transistor 32 is set to 2I, the collector current of the transistor 38 is set to I, and in response to changes in the input voltage, the collector current of the transistor 20 is set to I+ΔI, and the collector current of the transistor 22 is set to I-. Assuming ΔI,
As a result of the current combination of transistors 36 and 38, the base current of transistor 2 is given by ΔI. Then, when the base-emitter voltage V _BE (=V _F ) of the transistor 42, the forward voltage drop of the diode 44 is V _F , and the equivalent resistance value set by the resistance value setting circuit 40 is Ry, the output terminal 4
The rectified output voltage V _O generated in 6 is: V _O = ΔI・Ry−2V _F ……(2) Substituting the above equation (1) into this equation (2), V _O = ΔI・Rx・(Q _A /Q _B )−2V _F ……(3). However, V _O ≫ _{V F.}

Therefore, although the resistor 10 actually formed on the semiconductor integrated circuit has a small value and a small area, the operation of the resistance value setting circuit 40 causes the equivalent resistance value Ry to be larger than Rx. Therefore, it is possible to realize a high output of the rectified output V _O.

Moreover, according to such a configuration, the circuit current of the rectifier circuit is small, and current loss can be suppressed.

FIG. 3 shows another example of application of the invention.
In this embodiment, the resistance value setting circuit is used as an output resistor of an amplifier circuit, and parts common to those in the above embodiment are given the same reference numerals.

This amplifier circuit is composed of a differential amplifier, and this differential amplifier is equipped with a pair of transistors 52 and 54 having a common emitter, and a constant current source that sets an operating current between the emitter and the common line. 56 are installed. An input signal to be amplified is applied to an input terminal 58 formed at the base of the transistor 52, and a predetermined bias is applied to a bias input terminal 60 formed at the base of the transistor 54. The collector of the transistor 54 is connected to the power supply line, and a transistor 62 having a common base and collector is connected between the collector of the transistor 52 and the power supply line, and the output taken out from the collector of the transistor 52 is connected to the power supply line. added to the base. That is, the transistors 62 and 64 constitute a current inversion circuit, and the transistor 64 has its emitter connected to the power supply line and its collector connected to the base of the transistor 2.

According to such a configuration, compared to the case where the output resistor 66 is installed, the value of the resistor 10 can be set smaller, its area can be reduced, and high output can be realized.

Note that although the embodiment describes the setting of an enlarged resistance value, the present invention can also be used to reduce the resistance value.

As explained above, according to the present invention, the actual resistance value can be expanded or reduced to form a desired equivalent resistance value, and it can be installed in an output circuit such as an amplifier circuit or a rectifier circuit to achieve high output. can be realized.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the resistance value setting circuit of the present invention, FIG. 2 is a circuit diagram showing a rectifier circuit which is an application example of the resistance value setting circuit of the present invention, and FIG. 3 is a circuit diagram showing the resistance value setting circuit of the present invention. FIG. 7 is a circuit diagram showing an amplifier circuit which is another application example of the value setting circuit. 2...Transistor, 8...Current inversion circuit, 1
0...Resistance.

Claims (1)

[Claims] 1. A resistance value setting circuit, characterized in that a resistor is connected between an emitter of a transistor and an input part of a current inversion circuit, and an output part of the current inversion circuit is connected to a base of the transistor.