JPS62272606A - Power amplifier circuit - Google Patents

Abstract

PURPOSE:To reduce the voltage fluctuation of a power source, and to exactly reproduce a signal wave, or a dynamic range, by driving a power amplifier on one side out of two power amplifiers with a negative phase against the power amplifier on the other side. CONSTITUTION:At the time of operating the first power amplifier 1 on one side in a positive half cycle, and permitting a load current IL to flow from a positive power source circuit 3, the second power amplifier 2 on the other side is operated in a negative half cycle, and a load current, the inverse of IR flows in from a negative power circuit 4. And in the period of the following half cycle, a reverse operation to the previous period is performed, and the currents IL and IR, and the currents, the inverse of IL, and the inverse of IR, are permitted to flow in the positive and the negative power source circuits by every half cycle alternately, and as a resulted, only a load current of one channel sequence is always permitted to flow, and it is possible to suppress the voltage fluctuation due to impedance r0 in the power source to a slight degree, same as that in one channel, to perform the transmission of an input waveform with high fidelity, and to prevent deterioration in the dynamic range.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) This invention is applicable to, for example, a stereo power amplifier,
This invention relates to a power amplifier circuit configured to minimize the influence of the voltage fluctuation rate of the power supply when two power amplifiers are connected to a common power supply circuit from an economical standpoint.

<Prior Art> Generally, as an example of the configuration of a stereo power amplifier circuit consisting of two first and second power amplifiers for the L channel and the R channel, a common power supply circuit is used as shown in FIG. (23).

(24) is the first power amplifier (21) for the L channel.
and a second power amplifier (22) for the R channel are connected in parallel, and in use, the power amplifiers (1) and (2) are driven in the same phase, and the load The L channel speaker (25) and the R channel speaker (26) are connected so that they have the same polarity.

<Problems to be solved by the invention> On the other hand, in the conventional example described above, the power supply circuit (23), (
24) consists of the resistance of the secondary winding of the power transformer, the resistance of the connecting conductor, etc., and has a configuration equivalent to the impedance represented by ro in Figure 5 being inserted in series. Therefore, when the output current flows into the power amplifier, the impedance r. A voltage drop occurs due to
The voltage applied to the power amplifier will fluctuate.

6 and 7 show this state in graphs, where the voltages of the positive power supply circuit (23) and the negative power supply circuit (24) are set to +Vcc and +Vcc, respectively, and the power amplifier (21)
) is VoL, the impedance is r because power flows from the positive power supply circuit (23) in the positive half cycle of the output VoL. This causes a voltage drop of +ΔVccL, and +Vcc fluctuates as shown by the dotted line.

Also, in the negative half cycle of the output VoL, the negative power supply circuit (2
Similarly, since the current flows from 4), r. by −ΔV
This causes a voltage drop of ccL, as shown by the same dotted line (-Vc
c changes.

Generally, a music signal has many in-phase components between the R channel and the R channel, but when the L and R channels are driven in the same phase as in a conventional stereo amplifier circuit, the 7th channel
As shown in the graph in the figure, the amount of fluctuation in the power supply voltage is the sum of the fluctuations due to the inflow current to both L%R channels, that is, +(ΔVccL + ΔVccR) and -(ΔVceL + ΔVccR), which are so large that they cannot be ignored. Then, each output waveform VoL (or VoR) is VoL' (or VoR) when there is no voltage fluctuation indicated by one point f (i).
'), it had the disadvantage of being limited in its large output and not being able to accurately reproduce the original signal waveform or the dynamic range of the music.

Therefore, the present invention eliminates the above-mentioned drawbacks of the conventional example by driving two power amplifiers (1) and (2) with one power amplifier in the opposite phase to the other, thereby reducing the voltage fluctuation of the power supply. The purpose is to accurately reproduce signal waveforms and dynamic ranges.

<Means for Solving the Problems> The structure of the present invention for achieving the above object will be explained using FIGS. 1 to 4 corresponding to the embodiments. Power supply circuit (3).

(4), which are commonly connected to a first power amplifier (1) and a second power amplifier (2) corresponding to the R channel and the R channel, respectively. When power amplifier (1) is driven with a positive phase signal voltage -VIL, the other second power amplifier (2) is configured such that it is driven with an opposite phase signal voltage -VIR.

<Operation> According to the present invention, when one of the first power amplifiers (1) operates in a positive half cycle and the load current IL flows from the -4=positive power supply circuit (3),
The other second power amplifier (2) operates in a negative half cycle, and the load current -IR flows in from the negative power supply circuit (4). A negative current -IL flows into the first power amplifier (1) from the power supply circuit (4), and a positive current -IR flows into the second power amplifier (2) from the power supply circuit (3). In both positive and negative power supply circuits, IL and IR, and -IL and -IR,
The current flows alternately every half cycle, and as a result, only the load current for one channel flows at all times, and the current for two channels does not flow at the same time for each cycle as in the conventional case. Power supply impedance r. This makes it possible to suppress voltage fluctuations due to noise to a slight degree as in the case of one channel, thereby ensuring faithful transmission of the input waveform and preventing deterioration of the dynamic range.

<Example> A detailed description of the present invention will be given below with reference to Sekibe: (]),
(2) are the first and second power amplifiers, respectively. For example, if the first power amplifier (1) is for the R channel, the second
The power amplifier (2) is for the R channel.

Each power amplifier (1), (2) is connected to a positive power supply circuit (3) and a negative power supply circuit (4) so as to share a common power supply.

An L channel speaker (5) is connected as a load to the first power amplifier (1), and an R channel speaker (6) is connected to the second power amplifier (2) which is driven in the opposite phase. The terminals are connected with the + and - terminals reversed.

In this embodiment, a phase inversion circuit () is connected to the input terminal of the second power amplifier (2), assuming that R and L in-phase input signals are applied from a normal preamplifier. The input signal VIR is inverted by this phase inversion circuit (7) and is applied to the second power amplifier (2) as a signal -\/IR of opposite polarity.

If a signal of opposite polarity is separately obtained for only one channel, the input signal may be directly applied as power to the amplifier (2).

FIG. 2 shows another embodiment in which 12
The output terminal to which the speaker of the power amplifier (2) should be connected (
8) is displayed in reverse to the actual polarity of the second power amplifier (2). In this embodiment, when connecting the speaker (6), unlike the former embodiment, there is no need to consciously connect the polarity in the opposite direction. It has the feature that it can be treated like a conventional stereo amplifier.

FIG. 3 shows yet another embodiment, in which a power amplifier (2)
is driven in reverse phase as in the previous embodiment, but
It has a configuration in which a phase inversion circuit (9) is connected to the output section. Like the other embodiments mentioned above, this embodiment is not only convenient in use because it is not necessary to consciously connect the speaker (6) as a load in an opposite phase; 9) can also be used as a reverse circuit.

<Effects of the Invention> Since the present invention has the above configuration, the two first and second stereo power amplifiers are driven in opposite phases. Therefore, when one power amplifier operates in a positive half cycle, the other power amplifier operates in a negative half cycle, and as in the conventional example, the two power amplifiers are driven in phase, and the power supply is Since it is not equivalent to connecting in parallel, it is equivalent to connecting two power amplifiers (1) and (2) alternately every half cycle for each positive and negative power supply. The load current of the circuit is exactly the same as when there is only one power amplifier, and there is an advantage that fluctuations in the power supply voltage are suppressed to a negligible extent.

Therefore, the output is no longer limited by fluctuations (decrease) in the power supply voltage, and even signal waveforms with large amplitudes at high outputs are reproduced extremely faithfully to the input, and the dynamic noise in the music signal is suppressed. All in all, you can get powerful playback sound without any problems.

Furthermore, since the load current of the power supply only needs to be substantially for one channel, the second consideration in designing for voltage fluctuation rate is reduced.
This also has the effect of reducing the manufacturing cost of the product.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of a power amplifier circuit according to the present invention,
Fig. 2 is a block diagram of another embodiment, Fig. 3 is a block diagram of another embodiment, Fig. 4 is a time characteristic diagram showing the relationship between the output waveform and power supply voltage fluctuation of this embodiment, and Fig. 5 6 is a configuration diagram of a conventional power amplifier circuit, and FIGS. 6 and 97 are time characteristic diagrams showing the relationship between the output waveform and power supply voltage fluctuation in the conventional example. In the figure, (1) is the 11 power amplifier, (2) is the second power amplifier, (3) is the positive power supply circuit, (4) is the negative power supply circuit, (7) is the phase inversion circuit, and (8) is the negative power supply circuit. ) is the output terminal.

Claims (1)

[Claims] [1] A first channel power amplifier (1) commonly connected to one each of positive and negative power supply circuits (3) and (4).
and a second channel power amplifier (2), the power amplifier circuit being configured such that the amplifiers (1) and (2) are driven in opposite phases to each other. [2] The power amplifier (1) or the power amplifier (2)
The power amplifier circuit according to claim 1, wherein a phase inversion circuit (7) is connected to one input section of the power amplifier circuit. [3] The polarity display of the output terminal (8) of the power amplifier (2) driven with the opposite phase or the power amplifier connected to the phase inversion circuit (7) is the actual output of the power amplifier. The power amplifier circuit according to claim 1, wherein positive and negative polarities are displayed in reverse. [4] The power amplifier (1) or the power amplifier (2)
), in which a phase inversion circuit (9) is connected to the output section of a power amplifier driven in an opposite phase.
] The power amplifier circuit described in section.