JP3152598B2 - Hybrid integrated circuit device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid integrated circuit device, and more particularly, to an improvement of a hybrid integrated circuit device equipped with an amplifier circuit used for a vehicle-mounted audio amplifier or the like.

[0002]

2. Description of the Related Art Most of the power consumption in a general amplifier is consumed by a power transistor in the last stage of the amplifier. In general amplifiers, a constant power supply voltage that can extract the maximum output is supplied to the power transistor in the final stage, so such a high power supply voltage is used even when the output amplified signal is minute or no signal. The power is supplied to the power transistor at the last stage of the amplifier, and there is a large loss in power consumption with respect to the output power.
In particular, this problem was remarkable when applied to an in-vehicle audio amplifier or the like, which requires only a battery as a power source and requires an efficient amplifier.

The conventional example described below has been proposed to avoid such a problem, and the power supply voltage (+ Vc) supplied to the power transistors (TR1, TR2) at the last stage of the amplifier (3) is changed. A hybrid IC mounted on a vehicle equipped with an amplifier circuit for improving efficiency by following and increasing and decreasing an amplified signal (ZS). As shown in FIG. 7, a positive-side control unit (1), a negative-side control unit (2), and an amplifier (3) provided with a push-pull power transistor (TR1, TR2) in the last stage are shown in FIG. 1
0, choke coils (L1, L
2) A switching transistor (Q1, Q2), a diode (D1, D2), and a capacitor (C1, C2) constituting a step-down chopper are mounted on a thick film substrate (not shown), and an audio signal input from the outside. Amplify the input signal (AS) such as to generate an amplified signal (ZS),
An amplification circuit for outputting to a speaker (SP) connected to the outside is mounted.

The positive side control unit (1) has a comparator (CMP) and an offset voltage generation unit (OG) as shown in FIG. 8, and when the amplified signal (ZS) swings to the positive side, as shown in FIG. This circuit generates a positive-side power supply voltage (+ Vc) that changes following the amplified signal (ZS). The negative-side controller (2) also has the same configuration, and generates a negative-side power supply voltage (-Vc) that changes following the amplified signal (ZS) when the amplified signal (ZS) swings to the negative side. Circuit.

The operation of the above device will be described below.
First, a power supply voltage (± Vcc) is supplied to the hybrid IC, and the positive side control unit (1) and the negative side control unit (2) turn on / off the switching transistors (Q1, Q2).
F operation is controlled, and external choke coils (L1, L
2) The power supply voltage (± Vcc) is reduced by the positive / negative step-down choppers (4, 5) composed of the switching transistors (Q1, Q2), diodes (D1, D2) and capacitors (C1, C2). Then, the power supply voltage (± Vc) of the amplifier (3) is generated and supplied to the amplifier (3).

Next, the audio signal (AS) is input from the outside and amplified by the amplifier (3) to generate an amplified signal (ZS) and output it to the speaker (SP). The amplified signal (ZS) is fed back to the positive control unit (1) and the negative control unit (2), and at the same time, the power supply voltage (± Vc) of the amplifier (3) is also controlled by the positive control unit (1) and the negative control unit. Returned to (2).

At this time, in the positive side control unit (1), a constant voltage is added to the amplified signal (ZS) by the offset voltage generation unit (OG), and this is added to the power supply voltage (+) by the comparator (CMP).
Vc). If the power supply voltage (+ Vc) is higher than the amplified signal (ZS) with the added constant voltage, the output goes high (hereinafter referred to as "H"), and the switching transistor (Q1) in FIG. 7 is turned on. To increase the power supply voltage (+ Vc).

Conversely, an amplified signal (Z
If the power supply voltage (+ Vc) is lower than the power supply voltage (+ Vc), the output thereof becomes low level (hereinafter referred to as “L”), and the switching transistor (Q1) in FIG.
Vc). In this way, the positive-side step-down chopper (4) is controlled so that the power supply voltage (+ Vc) always follows the amplified signal (ZS) on which a constant voltage is added.

Similarly to the positive control unit (1), when the amplified signal (ZS) swings to the negative side, the negative control unit (2) changes following the amplified signal (ZS). Power supply voltage (-V
The negative side step-down chopper (5) is controlled to generate c). In this way, the positive-side control unit (1) drives the step-down chopper so as to generate a positive-side power supply voltage (+ Vc) that follows a voltage obtained by adding a constant voltage to the amplified signal (ZS). Then, as shown in FIG. 9, a positive power supply voltage (+ Vc) in which a constant voltage is added to the amplified signal (ZS) is generated.

Similarly, on the negative side, as shown in FIG. 9, the negative power supply voltage (-Vc) which changes following the voltage obtained by adding a constant voltage to the amplified signal (ZS) which has been shifted to the negative side. Will be generated. The positive-side control unit (1) and the negative-side control unit (2) operate alternately as the amplified signal (ZS) swings positively and negatively. Therefore, the power supply voltage (ZS) changes following the amplified signal (ZS). ± Vc) to these control units (1, 2)
Are not generated at the same time.

As described above, the positive control unit (1) and the negative control unit (2) operate alternately, and as shown in FIG. 9, the power supply voltage (±) having an absolute value larger than the amplified signal (ZS). Vc) is the last power transistor (TR1, T1) of the amplifier (3).
R2), the power supply voltage (± Vc) increases when the amplified signal (ZS) is large, but the power supply voltage (± Vc) decreases when the amplified signal (ZS) is small, so that the output power is reduced. Power consumption loss for
Efficiency has been improved compared to a general amplifier that uses a constant voltage at which the maximum output can be taken out as a power supply voltage of the amplifier.

[0012]

However, the conventional hybrid IC has the following problems. That is, in the above circuit configuration, as shown in FIG. 7, a total of two step-down choppers (4, 5) are required on the positive side and the negative side, so that the choke coils (L1, L2)
Are also required, and the switching transistors (Q1,
The switching noise of Q2) leaks out of these two choke coils (L1, L2), affecting peripheral devices.

In particular, when used in a vehicle-mounted audio amplifier or the like, this noise jumps into a radio tuner that is essential for a vehicle-mounted audio system, and the noise is generated when the tuner operates. Occurs. In order to reduce this noise, it is necessary to take measures such as providing a shield cover for the choke coils (L1, L2).
2), two shield covers are also required, which causes problems such as an increase in cost.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional disadvantages. As shown in FIG. 1, an amplifying section for amplifying an input signal and outputting an amplified signal includes at least a positive side signal. A positive chopper power supply with a choke coil,
When the amplified signal swings to the positive side, a positive auxiliary power supply unit that generates a positive power supply voltage that changes following the amplified signal and supplies the power supply voltage to the amplification unit, and at least a negative choke coil A negative-side chopper power supply, and when the amplified signal swings to the negative side, generates a negative-side power supply voltage that changes following the amplified signal and supplies the negative-side auxiliary voltage to the amplifier. An amplifier circuit having a power supply unit is mounted, and the positive choke coil and the negative choke coil are configured as one shared choke coil wound on the same iron core. An object of the present invention is to provide a hybrid IC equipped with an amplifier capable of reducing adverse effects on peripheral devices due to noise and reducing costs by using a hybrid integrated circuit device.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a hybrid integrated circuit device according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a hybrid integrated circuit device according to the present embodiment, and FIG. 2 is a circuit configuration diagram of a positive control unit. FIG. 3 is a diagram for explaining the relationship between the positive and negative power supply voltages (± Vc) supplied to the amplifier (13) by the positive side step-down chopper and the negative side step-down chopper according to the present embodiment and the amplified signal (ZS). FIG. 4 shows a common choke coil (L
It is a figure explaining z).

This hybrid integrated circuit device is a hybrid IC equipped with an audio amplifier. As shown in FIG. 1, a positive control unit (11), a negative control unit (12), an amplifier (13), a switching transistor ( Q11, Q1
2) A diode (D11, D12) and a capacitor (C11, C12) are mounted on a thick film substrate (not shown), and two choke coils (L11, L12) are identical as external components as shown in FIG. It is provided with a common choke coil (Lz) configured to be wound on an iron core.

The positive control section (11) is a circuit having a comparator (CMP) and an offset voltage generating section (OG) as shown in FIG. 2, and the amplified signal (ZS) is shifted to the positive side. During the swing, a voltage obtained by adding a constant voltage to the amplified signal (ZS) and the positive side power supply voltage (+ V
c), the switching transistor (Q1
The ON / OFF operation of 1) is controlled.

A positive-side step-down chopper comprising a switching transistor (Q11), a diode (D11), a capacitor (C11) and a positive-side choke coil (L11) reduces the applied power supply voltage (+ Vcc). This circuit generates a power supply voltage (+ Vc) on the positive side of the amplifier (13) and supplies it to the amplifier (13). The positive side step-down chopper and the positive side control section (11) constitute an example of a positive side auxiliary power supply section.

The negative control section (12) has the same circuit configuration as the positive control section (11) shown in FIG.
When the voltage swings to the negative side, a voltage obtained by adding a constant voltage to the amplified signal (ZS) and the power supply voltage (−V
c), the switching transistor (Q1
2) The ON / OFF operation is controlled. Switching transistor (Q12), diode (D1
2), a negative-side step-down chopper comprising a capacitor (C12) and a negative-side choke coil (L12) lowers the applied power supply voltage (-Vcc) to reduce the power supply voltage (-Vcc).
The power supply voltage (−Vc) on the negative side of 3) is generated and the amplifier (1) is generated.
It is a circuit to supply to 3). The negative side step-down chopper and the negative side control unit (12) constitute an example of a negative side auxiliary power supply unit.

The amplifier (13) is an example of an amplifier,
An input signal such as an audio signal input from outside (A
S) is a circuit that amplifies S) to generate an amplified signal (ZS) and outputs it to a speaker (SP) connected to the outside. The operation of the above device will be described below. First, the power supply voltage (± V
cc) is input to the hybrid IC, and the ON / OFF operation of the switching transistors (Q11, Q12) is controlled by the positive side control unit (11) and the negative side control unit (12). Transistor (Q11, Q12), diode (D1
1, D12) and capacitors (C11, C12), the power supply voltage (± Vcc) is reduced by the positive / negative step-down chopper, and the power supply voltage (± Vc) of the amplifier (13) is generated. (13).

Next, the input signal (AS) is input from the outside and is amplified by the amplifier (13) to generate an amplified signal (ZS) and output it to the speaker (SP). The amplified signal (ZS) is fed back to the positive control unit (11) and the negative control unit (12), and at the same time, the power supply voltage (± Vc) of the amplifier (13).
Is also fed back to the positive control unit (11) and the negative control unit (12).

At this time, in the positive control section (11), the offset voltage generation section (OG) adds a constant voltage to the amplified signal (ZS), and compares this with a power supply voltage (+ Vc) by a comparator (CMP). ing. If the power supply voltage (+ Vc) exceeds the amplified signal (ZS) with the added constant voltage, the output becomes "H" and the switching transistor (Q11) in FIG. 1 turns on to increase the power supply voltage (+ Vc). Let
Conversely, if the power supply voltage (+ Vc) is lower than the amplified signal (ZS) on which the constant voltage is added, the output becomes "L" and the switching transistor (Q11) in FIG. 1 is turned off to turn off the power supply voltage (+ Vc). Lower. In this way, the positive-side step-down chopper is controlled such that the power supply voltage (+ Vc) always follows the amplified signal (ZS) on which the constant voltage is added.

Similarly, in the negative side controller (12), when the amplified signal (ZS) swings to the negative side, the amplified signal (Z
The negative-side step-down chopper is controlled so as to generate a negative-side power supply voltage (-Vc) that changes following S). As described above, the positive-side control unit (11) controls the step-down chopper to generate the positive-side power supply voltage (+ Vc) that follows the voltage obtained by adding a constant voltage to the amplified signal (ZS). Then, a positive power supply voltage (+ Vc) in which a constant voltage is added to the amplified signal (ZS) is generated as shown in FIG. Similarly, the negative power supply voltage (−−) that follows a voltage obtained by adding a constant voltage to the amplified signal (ZS) swinging to the negative side.
Vc) is generated.

In this manner, the positive side control section (11) and the negative side control section (12) operate alternately, and as shown in FIG. 3, the power supply voltage (A) having an absolute value larger than the amplified signal (ZS). ± V
c) is supplied to the power transistor (TR1, TR2) at the last stage of the amplifier (13), so that the amplified signal (Z
S) is small, the power supply voltage (± V
c) is also reduced, and the loss of power consumption with respect to the output power is reduced, so that the efficiency is improved as compared with a conventional amplifier that uses a constant voltage at which the maximum output can be taken out as the power supply voltage of the amplifier.

According to the hybrid IC according to the present embodiment, the choke coil (L11) of the positive step-down chopper and the choke coil (L12) of the negative step-down chopper are configured as shown in FIG.
As shown in (1), it is configured as one shared choke coil (Lz) wound around one iron core, which is a feature of the present invention. In the shared choke coil (Lz), in the amplifier circuit having the above configuration, the positive control unit (11) and the negative control unit (12) operate alternately as the amplified signal (ZS) swings positive and negative. As shown in FIG. 3, when a current flows through the positive choke coil (L11), a constant voltage is applied without flowing a current to the negative choke coil (L12), and conversely, a negative choke coil (L12) is applied. )
When a current flows through the choke coil on the positive side (L1
In 1), since a constant voltage is applied without flowing a current, there is almost no adverse effect on the mutual coils due to the current flowing through these coils, and thus the single choke coil (Lz) is configured. There's nothing wrong with that.

In practice, the waveform of the positive power supply voltage (+ Vc) generated by the positive control section (11) is such that the amplified signal (ZS) is positively deviated as shown in FIG. Z
S) is changed so as to follow a voltage obtained by adding a constant voltage to S. However, when the amplified signal (ZS) swings negatively, the coil (L12) of the negative step-down chopper is switched from the coil (L12) of the positive step-down chopper. As shown in FIG. 3, the electromotive force induced in the coil (L11) rises / falls in a mountain-like waveform.

However, at this time, the speaker (SP), which is a load, is not connected to the positive side chopper.
No current flows through the coil of the negative side step-down chopper (L
From 12), power consumption due to the electromotive force induced in the coil (L11) of the positive side step-down chopper is zero. Similarly, with the negative power supply voltage (-Vc) generated by the negative control unit (12), when the amplified signal (ZS) swings positively, the coil (L11) of the positive step-down chopper is used.
Thus, a waveform as shown in FIG. 3 is drawn by the electromotive force induced in the coil (L12) of the negative step-down chopper. At this time, the speaker (S
Since P) is not connected, the current does not flow to the speaker (SP) even if the voltage rises or falls, and the coil (L11) of the positive side step-down chopper changes from the coil (L11) of the negative side step-down chopper. Since the power consumption due to the electromotive force induced in L12) is zero, there is no power consumption loss. Therefore, even if these coils (L11, L12) are wound around a common iron core to form one shared choke coil (Lz), there is no problem because there is no loss in power consumption.

As described above, by using one common choke coil (Lz) as the choke coil of the step-down chopper on both the positive and negative sides, the number of parts is reduced as compared with the conventional case requiring two choke coils. Also, since only one shield cover is required for noise suppression, two coils,
The number of parts can be reduced as compared with the conventional case requiring two shield covers, and the cost can be reduced accordingly. In addition, as shown in FIG. 4, a coil configured by winding two types of coils on the same iron core can be seen to be used as a transformer, but is used as a choke coil as described above. The use was not found in the past.

In the prior art, two sources of noise were the two choke coils (L1, L2). However, according to the present embodiment, the number of sources of noise is one, so that the adverse effect of noise is reduced. Reduction becomes possible. Further, since a constant voltage is applied to the coil on the non-operating side, noise hardly jumps out of the coil. For example, when a current flows through the positive choke coil (L11) and the negative choke coil (L12) is operated, a constant voltage is applied to the negative choke coil (L12). 2) makes it difficult for the magnetic field generated by the current to leak due to the application of a constant voltage to cause noise.

FIGS. 5 and 6 show graphs of experimental results of the frequency dependence of the intensity of the switching noise which proves this fact. FIG. 5 is a graph showing the switching frequency of the switching transistor according to the conventional circuit and the intensity at that time, and FIG. 6 is a graph showing the switching frequency according to the present embodiment and the intensity at that time. As shown in FIG. 5, in the related art, first-order to higher-order harmonics generate strong spectral noise, and this strong noise jumps into a peripheral device, for example, a car audio tuner, and the noise is generated from the tuner. However, in the present embodiment, as shown in FIG. 6, the intensity of the spectrum-like noise of the first to higher harmonics is considerably reduced as compared with the related art. Can be reduced, and the adverse effect of noise can be reduced.

In the present embodiment, the use of the audio amplifier is not particularly limited. However, the use of the audio amplifier is desirably used for a vehicle-mounted audio amplifier that drives the amplifier using a battery of a single power supply. This is because there is a demand to reduce power consumption as much as possible in order to effectively utilize the limited battery voltage. In such a case, for example, the voltage of the battery is changed to DC / DC.
Generated by a converter, etc., and the above constant power supply voltage (± V
cc) may be generated and supplied to the circuit.

In this embodiment, the common choke coil (Lz) is mounted on the hybrid IC as an external component of the thick film substrate. However, the present invention is not limited to this.
For example, the same effect can be obtained by directly mounting on a thick film substrate.

[0033]

As described above, according to the hybrid integrated circuit device of the present embodiment, the amplifying section and the positive auxiliary power supply section having the positive chopper power supply having the positive choke coil are provided. Amplifying circuit having a negative side auxiliary power supply having a negative side chopping power supply having a negative side choke coil, and the positive side choke coil and the negative side choke coil being mounted on the same iron core. Is configured as a single common choke coil wound around.

Therefore, by using one common choke coil as the choke coil of the chopper power supply on both the positive and negative sides, the number of components is reduced as compared with the conventional case where two choke coils are required, and noise suppression is achieved. The number of parts can be reduced as compared with the conventional case that requires two coils and two shield covers, and the cost can be reduced.

Conventionally, noise was generated from two locations because there were two choke coils, which are noise sources, but according to the present invention, the noise source is reduced to one location and the noise is generated. Since a constant voltage is applied to the coil on the side without noise, it is difficult for noise to jump out of the coil,
It is possible to reduce the adverse effects of noise.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a hybrid integrated circuit device according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a positive control unit according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating operations of a positive control unit and a negative control unit according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a shared choke coil according to the embodiment of the present invention.

FIG. 5 is a graph illustrating the relationship between switching frequency and switching noise of a conventional hybrid integrated circuit device.

FIG. 6 is a graph illustrating a relationship between switching frequency and switching noise of the hybrid integrated circuit device according to the embodiment of the present invention.

FIG. 7 is a configuration diagram of a conventional hybrid integrated circuit device.

FIG. 8 is a circuit configuration diagram of a conventional positive-side control unit.

FIG. 9 is a diagram illustrating the operation of a conventional positive side control unit and negative side control unit.

FIG. 10 is a diagram illustrating a conventional choke coil.

[Explanation of symbols]

 (11) Positive control section (12) Negative control section (13) Amplifier (amplifying section) (Q11, Q12) Switching transistor (C11, C12) Capacitor (D11, D12) Diode (L11) Positive choke coil (L12) ) Negative choke coil (Lz) Shared choke coil (AS) Input signal (ZS) Amplified signal (OG) Offset voltage generator (CMP) Comparator

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H03F 1/00-3/72 G05F 1/56 330

Claims (3)

(57) [Claims] An amplifying unit that amplifies an input signal and outputs an amplified signal; and a positive chopper power supply having at least a positive choke coil. A positive-side auxiliary power supply that generates a positive-side power supply voltage that changes following an amplified signal and supplies the power supply voltage to the amplification unit; and a negative-side chopper power supply that includes at least a negative-side choke coil. When the amplified signal swings to the negative side, an amplification circuit having a negative-side auxiliary power supply unit that generates a negative-side power supply voltage that changes following the amplified signal and supplies the power supply voltage to the amplification unit, A hybrid integrated circuit device, wherein the positive choke coil and the negative choke coil are configured as one shared choke coil wound on the same iron core. 2. The hybrid integrated circuit device according to claim 1, wherein the shared choke coil is mounted as an external component on a thick film substrate on which the hybrid integrated circuit device is mounted. 3. The hybrid integrated circuit device according to claim 1, wherein said common choke coil is directly mounted on a thick film substrate on which the hybrid integrated circuit device is mounted.