Btl mode system

The Teac AP power amplifier uses its wide potential to satisfy all music lovers. With its 3 amplifier modes, you are bound to find the optimal setting for your Hi-Fi system. With its 3 amplifier modes, you are bound to find the optimum setting for your Hi-Fi system. With its audiophile design, XLR and RCA analogue inputs and attractive design, the qualities of this amplifier are clearly visible. Equipped with a Teac-compliant Ncore amplifier module , the AP power amplifier delivers superior power for your Hi-Fi system. Carried by a symmetrical design and audiophile components, this model will offer you a high fidelity experience.

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Btl mode system

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• Automotive audio power amplifier ICs
• Add to your order
• Teac AP-505 Black
• Automotive audio power amplifier ICs
• Legacy Models
• BTL-5825SL COMBI
• TARGETED RADIOFREQUENCY THERAPY
• TDA7498E Double 160W Power Amplifier Dual Channel Stereo Audio Amplifier Module Support BTL Mode
• A 2 W BTL single-chip class-D power amplifier with very high efficiency for audio applications

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Automotive audio power amplifier ICs

Effective date : Year of fee payment : 4. Year of fee payment : 8. Year of fee payment : An amplifier circuit of a BTL system is disclosed, which comprises a first operational amplifier which outputs an output signal having a same phase as an input signal input to a signal input terminal, a second operational amplifier which outputs an output signal having an opposite phase to the input signal, a voltage divider which generates a midpoint voltage of the input signal, a first resistor connected between an output terminal and a negative phase input terminal of the first operational amplifier, second and third resistors connected in series between the negative phase input terminals of the first and second operational amplifiers, a fourth resistor connected between an output terminal and the negative phase input terminal of the second operational amplifier, and an impedance converter connected between a midpoint voltage node of the voltage divider and a series-connection node of the second and third resistors.

The present invention relates to an amplification circuit, and in particular, to a power amplifier of a bridge tied load BTL system for audio a BTL power amplifier , which is used for, for example, a power amplifier for car audio of a high output specification. In a conventional BTL power amplifier, an input signal Vin is subjected to voltage-current conversion V-I conversion at a gm amplifier serving as a preamplifier to be made into a BTL signal current, and the BTL signal current is output to a circuit formed of first and second resistance elements connected in series.

The series-connection node of the first and second resistance elements are connected to a reference input terminal. A voltage generated across the first resistance element is amplified by a first operational amplifier, and is output from the first operational amplifier as a same phase output voltage VoutP having the same phase as the input signal Vin.

On the other hand, a voltage generated across the second resistance element is amplified by a second operational amplifier, and the amplified voltage is output from the second operational amplifier as an opposite phase output voltage VoutM having an opposite phase to the input signal Vin.

A closed loop gain GvP of the first operational amplifier and a closed loop gain GvM of the second operational amplifier can be given by the following expressions 1 and 2. Assuming that feedback quantity of the first operational amplifier and the second operational amplifier are defined as f 1 and f 2 , respectively, f 1 and f 2 can be given by the following expressions 3 and 4.

The feedback quantity do not depend on a frequency and is at a fixed value, and thus the BTL power amplifier of the above configuration is excellent in oscillation stability. In addition, since the circuit configuration of the first operational amplifier is the same as that of the second operational amplifier, the BTL power amplifier according to the above configuration has advantages that the circuit structure can be made symmetric and the circuit designing can be made easy.

However, in the power amplifier configured as described above, a noise and an offset voltage generated in the gm amplifier are amplified by the first operational amplifier and the second operational amplifier. Thus, the power amplifier as described above is unsuitable for use in a power amplifier of a low noise and a low offset voltage. Particularly, in the case of applying the circuit of the above configuration to an audio power amplifier or the like which is made into an integrated circuit, a sound quality is deteriorated if the noise is large, and a POP noise becomes large if the offset voltage is large.

In order to attain a low offset voltage, high accuracy is required for elements forming the gm amplifier, which increases the chip area of the gm amplifier. A concrete example of the gm amplifier, which is a preamplifier in the BTL power amplifier circuit of the above configuration, is disclosed in Jpn.

According to a first aspect of the present invention, there is provided an amplifier circuit of a BTL system, comprising:. According to a second aspect of the present invention, there is provided an amplifier circuit of a BTL system, comprising:. First, an amplifier circuit made by improving the conventional example for comparison with amplifier circuits of BTL system according to embodiments of the present invention will be described with reference to FIG.

The positive phase output terminal 71 configures one output terminal of the BTL power amplifier. The negative phase output terminal 72 configures the other output terminal of the BTL power amplifier. A resistance element R 2 is connected between the circuit point A and the circuit point C. Hereinafter, the operation and the problems of the circuit of FIG. For example, the operation before and after the output voltage VoutP of the operational amplifier 1 is clipped will be considered.

Accordingly, a current flowing through the resistance element R 2 becomes a current in accordance with the input voltage Vin. Since the current flowing through the resistance element R 2 flows through the resistance element R 3 as it is, a signal reversed of the output voltage VoutP of the operational amplifier 1 is output from the operational amplifier 2 as the output voltage VoutM of the operational amplifier 2.

Consideration will be given to a case in which neither the output voltage VoutP nor the output voltage VoutM is clipped. Assuming that an AC alternate current flowing through the resistance element R 2 is i R 2 , the output voltages VoutP and VoutM are given by the following expressions 5 and 6 , and a closed loop gain GvP of the first operational amplifier 1 and a closed loop gain GvM of the second operational amplifier 2 can be given by the following expressions 7 and 8.

Applying this state to formulas 5 to 8 , it is found that the gain GvM of the operational amplifier 2 also becomes zero just when the output voltage VoutP of the operational amplifier 1 is clipped. In other words, even if the output voltage VoutM of the operational amplifier 2 is not clipped, it is impossible to further drive the output of the operational amplifier 2 to attain a further amplified output power.

More specifically, in the power amplifier shown in FIG. In order to attain a large maximum output power, it is necessary that the output residual voltages of the output transistors at the driving side and the load side are made small to the limit in which the output residual voltages of the output transistors at the driving side and the load side are determined by the on-resistance of the output transistor of the operational amplifier.

However, it cannot be expected for the element configuring the power amplifier to be made so accurate as to satisfy the requirement. Hence, a large maximum output power cannot be attained. Generally, a main factor to determine the oscillation stability of a negative feedback amplifier circuit includes a feedback quantity.

It is a well known matter that the more the feedback quantity is, the more the negative feedback amplifier circuit is easily oscillated.

However, the power amplifier shown in FIG. Here, a feedback quantity f 1 that is a ratio of a voltage of the circuit point A with respect to the output voltage VoutP of the operational amplifier 1 is calculated. An impedance Z 2 in a case where a view is taken from the side of the resistance element R 2 to the circuit point C will be given by the following expression 9 :.

Therefore, f 1 is the following expression Here, it is known that, in general, a 2 has a frequency property and a 2 is small at a high frequency. From the expression 10 , it is found that f 1 has a frequency dependency and the larger the frequency becomes, the larger f 1 becomes.

In other words, in the power amplifier shown in FIG. Embodiments of the present invention will be described below, with reference to the drawings. In the following description, the same reference symbols are used for the same parts or portions. The positive phase output terminal of the first operational amplifier 1 configures one output terminal 11 of the BTL power amplifier. The junction of the second resistance element R 2 and the third resistance element R 3 constitutes a circuit point B.

The output terminal of the second operational amplifier 2 configures the other output terminal of the BTL power amplifier. A voltage divider circuit 14 for generating a midpoint voltage of the input voltage Vin is connected between the signal input terminal 10 and the reference voltage terminal The voltage divider circuit 14 is formed of a fifth resistance element Rin 1 and a sixth resistance element Rin 2 connected in series.

The junction of the fifth resistance element Rin 1 and the sixth resistance element Rin 2 constitutes a midpoint voltage circuit point D of the voltage divider circuit An impedance conversion circuit 3 is connected between the midpoint voltage circuit point D of the voltage divider circuit 14 and the circuit point B of the junction node of the second resistance element R 2 and the third resistance element R 3.

A resistance value ratio between the second resistance element R 2 and the third resistance element R 3 is 1:n arbitrary number , and a resistance value ratio between the fifth resistance element Rin 1 and the sixth resistance element Rin 2 is equal to the resistance value ratio between the second resistance element R 2 and the third resistance element R 3.

According to the present embodiment, the resistance value ratio between the fifth resistance element Rin 1 and the sixth resistance element Rin 2 is , and the resistance value ratio between the second resistance element R 2 and the third resistance element R 3 is also Consideration will be given to a case in which neither the output voltage VoutP of the operational amplifier 1 nor the output voltage VoutM of the operational amplifier 2 is clipped.

Assuming that an open loop gain of the operational amplifier 1 and an open loop gain of the operational amplifier 2 are a 1 and a 2 , respectively.

Accordingly, although the buffer amplifier 3 of the gain 1 is connected between the circuit point D and the circuit point B, supply and absorption of the current by the buffer amplifier 3 do not occur. In other words, there is no difference in the operation from the case where the buffer amplifier 3 is not provided.

Here, representing an AC current flowing through the resistance element R 2 by i R 2 and an AC current flowing through the resistance element R 3 by i R 3 , i R 2 and i R 3 will be given by the following expression The AC currents i R 2 and i R 3 in the expression 11 are supplied from the output terminal of the operational amplifier 1 via the resistance element R 1 , and flow into the output terminal of the operational amplifier 2 via the resistance element R 4.

When neither the output voltage VoutP of the operational amplifier 1 nor the output voltage VoutM of the operational amplifier 2 is clipped, the output voltages VoutP and VoutM are given by the following expressions 12 and 13 , respectively, and the closed loop gain GvP of the operational amplifier 1 and the closed loop gain GvM of the operational amplifier 2 are given by the following expressions 14 and 15 , respectively.

Accordingly, as the output voltage VoutP of the operational amplifier 1 and the output voltage VoutM of the operational amplifier 2 , signals having the reversed phase to each other are output so as to obtain a BTL signal. On the other hand, consideration will be given to a case in which Vin becomes larger and either the output voltage VoutP of the operational amplifier 1 or the output voltage VoutM of the operational amplifier 2 is clipped, for example, a case in which the output voltage VoutP of the operational amplifier 1 is only clipped.

In this case, the AC current i R 3 is given by the expression 16 , and the output voltage VoutM of the operational amplifier 2 and the closed loop gain GvM of the operational amplifier 2 are given by the following expressions 17 and 18 , respectively.

In this case, it is noted that the current value shown in the expression 16 is equal to the current value just before clipping as shown in the expression That is, due to the effect of the buffer amplifier 3 , it is possible to provide an amplification operation to substantially make the output amplitude larger without change of the gain of the operational amplifier 2 which is not clipped, before and after the VoutP which is the output voltage of the operational amplifier 1 is clipped.

The amplification correction operation by the buffer amplifier 3 is continued till both of the output voltage VoutP of the operational amplifier 1 and the output voltage VoutM of the operational amplifier 2 are clipped.

When both of the output voltage VoutP of the operational amplifier 1 and the output voltage VoutM of the operational amplifier 2 are clipped, the buffer amplifier 3 does not provide the amplification correction operation, though it provides the amplification. Accordingly, the BTL power amplifier according to the first embodiment has the following advantage.

That is, even when the closed loop gains GvP and GvM of the operational amplifiers 1 and 2 are not equal to each other, or the output residual voltages i. As a result, the BTL power amplifier can be sufficiently driven, and the maximum output power of the BTL power amplifier can be made sufficiently large. Now, a feedback quantity f 1 which is a ratio between the voltage at the circuit point A and the output voltage VoutP of the operational amplifier 1 is calculated. As described above, supply and absorption of the current by the buffer amplifier 3 do not occur in a low frequency in which the open loop gains a 1 and a 2 are sufficiently large.

Thus, the output impedance of the buffer amplifier 3 does not relate to the feedback quantity f 1. That is, the feedback quantity f 1 at the low frequency can be approximately represented by the following expression On the other hand, at the high frequency for example, several hundreds KHz to several MHz where the open loop gains a 1 and a 2 are small, the output impedance of the buffer amplifier 3 affects the feedback quantity f 1.

Briefly estimating, an impedance Zc in the case where a view is taken from the side of the resistance element R 3 to the circuit point C can be represented by the following expression Assuming that the output impedance of the buffer amplifier 3 is r 0 , the impedance Zb in the case where a view is taken from the side of the resistance element R 2 to the circuit point B is substantially represented by the following expression When the buffer amplifier 3 is configured by an emitter follower circuit or the like, the buffer amplifier 3 is normally more excellent than the operational amplifiers 1 and 2 in the high frequency property, so that the output impedance r 0 of the buffer amplifier 3 becomes dominant with respect to the impedance Zb.

Therefore, the feedback quantity f 1 at the high frequency can be represented by the following expression Consequently, by using an emitter follower of a broad band having a high input impedance and a low output impedance, the oscillation stability of the BTL amplifier can be improved even at the high frequency without making the feedback quantity f 1 extremely large. In addition, since an offset voltage generated between the input and the output of the buffer amplifier 3 is evenly applied to the resistance elements R 2 and R 3 , the offset between the BTL outputs VoutP and VoutM is not increased.

It means that there is no necessity to use a high-accuracy amplifier of a low offset, and the emitter follower which can be easily designed may be used. Thus, as compared to the case that a preamplifier is employed, a low offset voltage and a low noise can be expected. The BTL amplifier of the present embodiment is preferably used in particular for a power amplifier for car audio of a high output specification in which the maximum output power is important. A pnp transistor Q 2 has a base which is connected to the circuit point D, a collector which is connected to the ground node Vss, and an emitter connected to the power source node Vcc via a constant current source I 2.

An npn transistor Q 3 has a base which is connected to the emitter of the pnp transistor Q 2 , a collector which is connected to the power source node Vcc, and an emitter which is connected to the circuit point B which constitutes an output node of the buffer amplifier 3. A pnp transistor Q 4 has a base which is connected to the emitter of the npn transistor Q 1 , a collector which is connected to the ground node Vss, and an emitter which is connected to the circuit point B which constitutes the output node of the buffer amplifier 3.

The circuit shown in FIG. In this manner, it is possible to match the impedance in the case where a view is taken from the reference input Ref terminal 13 to the positive phase input terminal of the operational amplifier 1 with the impedance in the case where a view is taken from the reference input terminal 13 to the positive phase input terminal of the operational amplifier 2.

Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

An amplifier circuit of a BTL system, comprising: a first operational amplifier circuit which outputs an output signal having a same phase as an input signal input to a signal input terminal;. The amplifier circuit of a BTL system according to claim 1 , wherein the voltage dividing circuit comprises a fifth resistance element and a sixth resistance element which are connected in series between a positive phase input terminal of the first operational amplifier circuit and a reference input terminal, and.

The amplifier circuit of a BTL system according to claim 2 , wherein the resistance value ratio of the fifth resistance element and the sixth resistance element is 1:n, where n is an arbitrary number, and the resistance value ratio of the second resistance element and the third resistance element is 1:n, where n is an arbitrary number.

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Effective date : Year of fee payment : 4. Year of fee payment : 8. Year of fee payment :

Teac AP-505 Black

Irss w Schematic. The goal was simple; to test many existing BA transmitter designs, compare their performance, identify weaknesses and come up with a new BA transmitter design that improves sound quality, has very good frequency stability, maximizes transmitter's range, and is fairly simple for everyone to build. All products are quality checked. The extremely durable buried metal contruction gives FaradayCage performance needed to. They operate by rapidly switching back and forth between the supply rails, being fed by a modulator using pulse width, pulse density, or related techniques to encode the audio. The Zero DAC is a low cost Asian designed and manufactured digital to analog converter pre-amplifier. PCB size: 76MM. Seattle Area.

Automotive audio power amplifier ICs

Audio amplifiers are certainly the most interesting topic for the broadest range of engineers and enthusiasts. There is a vast number of different designs available, based on many different technologies. High-voltage HV sound distribution systems are commonly used for public announcements public address, PA in hospitals, train and bus stations, airports, and similar places where sound distribution over long distances is required. Depending on its rated power, the current through the load can reach high values, which requires the use of lower wire gauge numbers thicker wires with less resistance.

Legacy Models

The automated High Intensity Laser, so-called Robotic Scanning System delivers the most gentle and effective pain management to your patients! The healing effect of laser light is based on biostimulation and speeding up cell processes that contribute to pain suppression and faster injury recovery. The unique combination of 30W power and a nm wavelength allows for targeting deep-lying tissues, maximizing pain relief and delivering strong thermic therapies within a shorter time. Robotic Scanning System is an operator-free procedure that:. Patient position control ensures safe distance between patient and device. Medicine Science.

BTL-5825SL COMBI

Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. DOI: Emerging Technologies for the 21st Century. Conventional class-D amplifiers generate pulse-width-modulated PWM signals by comparing a triangle-wave with input-signals.

TARGETED RADIOFREQUENCY THERAPY

It increases the data transport quality and reduces the power supply noise, which make changes to your PC Hi-Fi system from the source. X-Hi uses high precision clocks coordinate with USB 3. The switchable power supply mode let the PC Hi-Fi enthusiasts to achieve different experiences.

TDA7498E Double 160W Power Amplifier Dual Channel Stereo Audio Amplifier Module Support BTL Mode

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Sometimes we need configurable multichannel amplifiers for experiments or for use in offices or schools. Here is a multi mode audio amplifier circuit based on TDAQ , configured for multi-mode function with four channel outputs. The circuit of the simple 4-channel multi mode audio amplifier is shown in Fig. It has four channels and each channel can provide around 11W over a load of 2-ohms and around 6W over a load of 4-ohms.

A 2 W BTL single-chip class-D power amplifier with very high efficiency for audio applications

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No Preview Available! It was designed for the best possible audio quality and features an extended low band roll-off frequency provided by a newly-developed NF circuit that does not require an external capacitor. Furthermore, crosstalk, which can cause muddiness in the audio output, has been significantly reduced by both circuit and wiring pattern improvements.