Stereo amplifier with SPDIF input. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Transistor power amplifiers

 Comments on the article

The proposed powerful stereo UMZCH with SPDIF input is designed to amplify audio signals fed to its input from analog and digital sources.

The rated output power of the amplifier is 2x25 W at a load of 4 ohms. Bandwidth - 0.02...20 kHz. The coefficient of non-linear distortion in the specified frequency band is not more than 0.15% (0,08% at a frequency of 1 kHz). The amplifier circuit is shown in fig. 1.

(click to enlarge)

The SPDIF converter (LC + PC) is assembled on a DA1 chip (UDA1350ATS) manufactured by Philips. SPDIF (Sony/Philips Digital Interconnect Format) is a digital audio interface. In it, samples (signal samples) are transmitted at a fixed frequency, bit by bit, in blocks of 32 bits, where 8 bits (4 at the beginning and 4 at the end) are used for synchronization and service information, and 24 bits are used for information (Fig. 2 ).

In most cases, a 16-bit sample is transmitted (CDs contain only 16-bit "sound"), and the lower 8 bits are zero. This interface is very simple and cheap and therefore widely used. The SPDIF interface supports three standard sampling rates: 32; 44,1 and 48 kHz.

(click to enlarge)

The UDA1350ATS, housed in a 28-pin SMD package, is a data stream recovery circuit for 24-bit stereo audio signal sampled at up to 48 kHz. The internal structure of the microcircuit is shown in fig. 3. When a signal appears at the SPDIF input, it is recognized by the decoder, processed, divided into two channels, the signals of which are converted to analog form and fed to the outputs (pins 15 and 17) DA1 (Fig. 1). The switching signal from pin 16 DA1 through a 2-transistor key VT1-VT2 acts on the switch DA2, which passes the decoded signals to the inputs of power amplifiers.

Toshiba's TC4053B switcher is a 3-channel 2-way multiplexer that allows you to select analog and digital signals. The structure of the IC is shown in fig. 4. Depending on the logical levels at the address inputs A, B, C and the enable input 1NH, signals from one of the inputs (0X and 1X, 0Y or 1Y, 0Z or 1Z) pass to the outputs X, Y, Z. This commutation is reflected in the microcircuit's truth table.

At voltages VDD = + / -5 V. Vss = 0 V, VEE = -5 V, the signal can vary in the range -5 ... + 5 V. ICs are available in several types of packages: DIP16 (TC4053VR - Fig. 5a), SOP16 (TC4053BF - fig. 56), SOL16 (TC4053BFN - fig. 5c) and TSSOP16 (TC4053BFT - fig. 5d). The pinout of the microcircuit is shown in fig. 6.

Power amplifiers DA3, DA4 (Fig. 1) are assembled on the LM2876 IC from National Semiconductor.

The LM2876 chip is an UMZCH with a maximum output power of 40 W at a load of 8 ohms and a harmonic coefficient of 0,1% in a frequency band of 0,02 .. .20 kHz. The IC has several protections (overload, overtemperature, power). It is produced in an 11-pin TO-220 package (Fig. 7).

The internal structure of the UMZCH is shown in fig. 8, and a typical switching circuit - in fig. 9.

The dependence of the harmonic coefficient K, on ​​the frequency is shown in fig. 10, in fig. 11 - from the output power.

The dependence of the dissipated power on the output and output power on the supply voltage is shown by the graphs in fig. 12 and 13 respectively.

The SA2 button in the amplifier (Fig. 1) turns on the “Pause” (“Mute”) low power mode.

The UMZCH is powered by a bipolar ± 25 V power supply. To power DA2, the positive supply voltage is reduced to 12 V by the DA6 integral stabilizer, and for DA1 - to 3.3 V, obtained using the DA5 stabilizer (AMS1117-3.3), manufactured by Advanced Monolithic Systems .

When assembling the amplifier, the DA3, DA4 microcircuits are installed on a finned heat sink with an effective area of ​​at least 100 cm2. Transformer T1 is wound on a toroidal core with a diameter of 100 mm and a cross section of 15x60 mm. The primary winding consists of 1250 turns of PEVTL-2 00,6 mm wire, and the secondary - 2x140 turns of PEVTL-2 01 mm.

Establishing an amplifier correctly assembled from serviceable parts is not difficult. The signal from the sound generator with a frequency of 1 kHz is fed to the inputs of the LC and PC. A load is connected to the output of the amplifier, on which the output signal is monitored by an oscilloscope. Its shape should repeat the shape of the input signal.

Author: V. Fedorov, G. Lipetsk

See other articles Section Transistor power amplifiers.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive Centennial battery on bacteria 23.04.2023 Scientists have developed a battery that uses spore-forming bacteria to generate electricity. Engineers at Binghamton University have used spore-forming bacteria to create a bio-battery that can be stored for long periods of time and will potentially work even after 100 years. The coin-sized fuel cell was sealed with a piece of Kapton tape, a material that can withstand high and low temperatures. This made it possible to preserve the material for long-term storage. When the tape was removed and moisture got inside, the bacteria mixed with a chemical germ that stimulated the microbes to produce spores. The energy of biochemical reactions was enough to power an LED, a digital thermometer, or a small clock. The researchers also found that thermal activation of bacterial spores reduced the time to reach full power from 1 hour to 20 minutes, and increased humidity increased electrical output. After a week of storage at room temperature, power generation decreased by only 2%. "The overall goal is to develop a microbial fuel cell that can be stored for a relatively long period of time without degrading biocatalytic activity, and also quickly activated by absorbing moisture from the air," said Sohin Choi, co-author of the study. The researchers said the current prototype is just the beginning of research. Although it shows good results for the full implementation and replacement of traditional batteries with bioaccumulators, such a fuel cell should turn on faster and produce more voltage.

Other interesting news:

▪ Stable miniature 3D airgel objects

▪ Transgenic product causes allergies

▪ The taste of fat

▪ amoeba in amber

▪ Traces of early life in precious stones

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Electrical safety, fire safety. Article selection

▪ article Railroad tracks for the model. Tips for a modeler

▪ article Who recognized Hitler as the man of the year? Detailed answer

▪ article Weather Records. Sky. Travel Tips

▪ article A good crystal filter for CW and AM. Encyclopedia of radio electronics and electrical engineering

▪ article Overhead power lines with voltage above 1 kV. Rapprochement of overhead lines with explosive and fire hazardous installations. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024