JPS58159001A - Low distortion amplifying circuit - Google Patents

Abstract

PURPOSE:To realize amplification of a low distortion factor without providing negative feedback, by connecting plural transistors (TR) which are diode-connected as a load of the collector. CONSTITUTION:Between the other terminal of a resistance R2 connected to an electric power source terminal Va, and a collector electrode of a TR T1, n-number of TRs having the same characteristics, which are diode-connected are provided. Each base-emitter voltate VBE of a TR T2 which is diode-connected is equal. Between a current I1 flowing in a base resistance R1 of the TR T1, and a current I2 flowing in the resistance R2, there is a difference by current amplification factor hPE times of the TR T1. When the product of a ratio of the resistance R1 and the resistance R2, and the current amplification factor hPE is made equal to the number (n) of the TR T2, a term of hPE is not contained in output voltage. As a result, the input voltage and the output voltage are connected linearly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a low distortion amplification circuit KII that does not use negative feedback.

In the past, negative feedback was considered an essential condition for constructing a low-distortion amplifier circuit using transistors, and this was considered an unavoidable means to cancel the nonlinearity that is a characteristic of transistors. It had been.

However, in the case of high-fidelity amplifiers, which are required in recent audio amplifiers, etc., the reduction in distortion due to negative part fi [is the opposite (it causes adverse effects such as unstable characteristics in the high range, and the high fidelity decreases). As a result of this, I have become very nervous.

The present invention has been made to eliminate the above-mentioned drawbacks, and it is an object of the present invention to provide a low distortion amplification circuit configured to achieve low distortion without applying negative feedback. Embodiments of the present invention will be described below with reference to WJ aspects.

Series III is a circuit diagram showing a low distortion amplification circuit according to an embodiment of the present invention, where IN is an input terminal, OUT is an output terminal, Va is a power supply terminal, R1 is a first resistor, 2 is a resistor 2, T1.
T-A! A plurality of (one) transistors T3 (41K transistors with the same characteristics) are used, and their collectors and paces are short-circuited, and a forward diode D is directly connected to the output terminal 0υ. It becomes.

(In this case, each transistor with the same characteristics is connected in series, so each base-emitter voltage VB
I becomes equal, and the current amplification rate Yhy of transistor T1
x, is the source voltage VOO1 input signal [Vi, output signal '1
11'VO, the first resistor R.

vtIL resistance 111R11c, Il=(V4-VBI)/Rxt, and the current resistor 8 which is connected to the second resistor R2Yfi is l2=IN・hy
The output signal V becomes x-hyx (Vi-VBI)/R1. is vo== Vaa -a, -im-%@VBI=Vo
o-Rz・hyx, (Vi VBI)/R1-1Vs
x= Vao −12・hym Vi/R1+(R
z11by] cT/Ri 5) Viiz (1 where R
When 2.hym/R1-a, substituting this value into K in the above equation (1), votech■. 0-Route ■1...(2).

In other words, as is clear from equation (2), the input signal ■1 input from the input terminal IN to the transistor T□ changes by a factor of 1 and comes out from the output terminal OUT.
/ Under the condition of R1 = a, by configuring each transistor' with one with the same characteristics, the transistor as a whole is non-linear! Even if it is an I element, negative feedback should not be applied (it can be operated as a distortion-free amplification circuit. ta increase rate hH by measuring circuitization! 6 Figure 2 shows an example of this, in which transistors t' (m+1) with the same characteristics are connected in parallel and the base b and emitter e are connected in common), and one transistor Only t base and collector V are short-circuited to form the base B, and the collectors l of the remaining m transistors are also AK'd to form the collector C.

The collector voltage fiA in such a composite transistor circuit is one component of the collector voltage *Ic of each transistor. Here, if the current amplification factor hlFE is large, the base current can be ignored, so the base current of the composite transistor circuit becomes the same as the collector current of one transistor. Therefore, when the current amplification factor hFi is sufficiently larger than mK, the current amplification factor tIFK of this composite circuit becomes 1. Multiple transistors in parallel VC! [If connected, the current amplification rate of the composite transistor circuit can be determined depending on the number of transistors.]
) value can be obtained.

As is clear from the above description, it is possible to realize a low distortion amplifier without applying a negative feedback Ilv by configuring an amplifier circuit using transistors having skew characteristics according to the present invention. In this embodiment, a high-fidelity amplifier can be constructed without suffering any negative effects. You can also get the same effect.

[Brief explanation of the drawing]

Figures @Ni1i) and @2 are both schematic diagrams showing embodiments of the present invention. IN...Input terminal, OUT...Output terminal, va
...Power terminal, Tl? "2...transistor, D...
··diode. Patent applicant Clarion Co., Ltd.

Claims (1)

[Claims] In a transistor amplifier circuit equipped with an input terminal, an output terminal, and a power supply terminal, a resistance K11il between the input terminal and the base of the transistor is lIkM, and a resistance K1112 between the output terminal and the power supply terminal and the same as that of the transistor. One forward diode configured by the collector-pace smoke path of the transistor with the characteristic is connected in series KlkM!
The product of the ratio of the first resistance and the second resistance and the current term neutrality of the transistor is the above I&(so that it is equal to 5
A low distortion amplification circuit constructed with 1-% mold.