JPS62130007A - Low frequency signal amplifier circuit - Google Patents

Abstract

PURPOSE:To improve the reproducing capability with low cost and low frequency by adopting the constitution that right/left power amplifiers are in BTL connection to double woofers only at a low frequency band. CONSTITUTION:Left/right signals are amplifier by power amplifiers 2, 3 through coupling capacitors C1, C2 normally and reproduced from speakers 5, 6 through the coupling capacitors C6, C7, Further, the left/right signals mixed by resistors R1, R2, are given to a low-pass filter 1, and only a low frequency band is inputted to a base of a transistor (TR) Q1 through a coupling capacitor C3. In setting resistor R4, R5 equal, the collector output and the emitter of the TR Q1 are inversed in the phase. In applying the output signal to the left/right power amplifiers 2, 3, through coupling capacitors C4, C5, the output voltage between the output terminals is twice in the normal signal and than the woofer 4 is driven by the normal double voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a low frequency signal amplification circuit in a cassette tape recorder with a radio receiver, a television receiver, or a stereo playback device.

Conventional technology In general, in stereo audio reproduction methods, left and right signals are amplified using a power amplifier circuit and connected to left and right speakers. Reproduction ability φ; Dedicated regeneration circuit for the 11υ vagina band,
A "3-dimensional" (hereinafter abbreviated as 3D) method using speakers is known. FIG. 2 shows a conventional 3D signal regenerator.

In Fig. 2, the left and right speakers 6.6 are connected to the power amplification paths 2 and 3 of the left and right people, and the left and right signals are further connected to the resistor R11.
r R12K, the signal is synthesized through a low-pass filter 1, and a power amplifier 7 drives a deep bass speaker 4. In addition, in Fig. 2, C11°C12, C13,
C14, C16, and C16 are coupling capacitors.

Problems to be Solved by the Invention However, in this kind of circuit configuration, a dedicated power amplifier is required for bass reproduction, which increases the number of components used and requires additional space for placement. There was a problem with rising prices.

Means to Solve the Problem The low frequency signal amplification circuit of the present invention connects the left and right speakers to the outputs of the left and right power amplification circuits, and in the low frequency band, the left and right power amplifiers are used for heavy bass. It is configured to be connected to the speaker via BTL.

Function: In addition to the left and right stereo signal amplification functions, the low frequency signal amplification circuit of the present invention has a BTL connection between the left and right power amplifiers to the deep bass speaker only for low frequency bands in order to reproduce deep bass. By doing so, it is possible to drive a dedicated speaker that reproduces deep bass using only the left and right power amplifiers that are conventionally required for stereo signal reproduction, improving the reproduction sound quality at a low cost, and especially improving the reproduction ability of low frequencies. It is possible to aim for

Embodiments Hereinafter, low frequency signal amplification circuits according to embodiments of the present invention will be explained with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In FIG. 1, 2 and 3 are left and right power amplifiers, and 5.6 is left and right speakers. Normally, the left and right signals are amplified by power amplifiers 2 and 3 through coupling capacitors C1 and C2, and reproduced by speakers 5 and 6 through coupling capacitors C6 and C7. Furthermore, the left and right signals mixed by resistors R1 and R2 pass through a low-pass filter 1, and only the low frequency band enters the transistor Q1 through a coupling capacitor C2.

Here, if the resistor R4 and the Rρ constant are set equal, the collector output and emitter output of the transistor Q1 will output signals whose phases are inverted. This signal is coupled to the capacitor C4,
When applied to the left and right power amplifiers 2 and 3 through C6, the outputs of the power amplifiers 2 and 3 are also inverted in phase, so if you look at the output voltages of these output terminals, a voltage twice the normal signal will appear. Therefore, the bass speaker 4 can be driven with twice the normal voltage.

Effects of the Invention As described above, the low frequency signal amplification circuit of the present invention uses BT only in the low frequency band for reproduction of heavy bass in the left and right power amplifiers.
It is configured so that it can be connected as an L, and therefore, by simply adding a phase inversion circuit to the conventional circuit, it is possible to improve sound quality and reproduce deep bass while minimizing the increase in price, making it extremely advantageous in practical terms. be.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a low frequency signal amplification circuit according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional low frequency signal amplification circuit. 1...Low pass filter, 2,3...Power amplifier, 4...Deep bass speaker, 5,6...
...Speaker, Ql...Phase inversion transistor. Name of agent: Patent attorney Toshio Nakao and 1 other person1-
--a-Ba-in-Fui-Ref 4-m-English person's entry σ-/l-Q 1 Figure 2.3---
tn4'44r 6.6--- 7. c'-1Q
---t-Hunn people Figure 2

Claims (1)

[Claims] The left and right speakers are connected to the outputs of the left and right power amplifiers, and in order to reproduce deep bass frequencies, the left and right power amplifiers connect BT to the deep bass speakers only for low frequency bands.
A low frequency signal amplification circuit characterized in that it is configured to be L-connected.