Voltage stabilizer for UMZCH on the TDA2030 chip. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Surge Protectors

 Comments on the article

Integrated circuits TDA2030, TDA2030H, TDA2030V, TDA2030A, TDA2030AH, TDA2030AV are high-quality single-channel audio power amplifiers. Microcircuits of this series have been very popular for two decades both in amateur radio designs and in industrial UMZCH. Usually, UMZCHs assembled on such microcircuits are connected to an unstabilized power source.

Such a solution leads to a decrease in the reliability of amplifiers, an increase in distortion, and a “shortage” of output power.

Microcircuits TDA2030 (without index "A") and domestic analogues K174UN19 allow bipolar voltage supply up to ±18 V and develop output power up to 14 W at a load of 4 ohms. The TDA2030A can be powered up to +22V and deliver up to 18W of output power into a 4 ohm load.

To improve the characteristics of the UMZCH on the TDA2030, it is advisable to power them through a bipolar voltage regulator. The power supply circuit for the UMZCH on the TDA2030 or K174UN19 is shown in Fig. 1.

The mains voltage is supplied to the step-down transformer T1 through the fuses FU1, FU2, the closed contacts of the switch SA1, the noise suppression LC filter L1-C1 and the current-limiting thermistors Rt1, Rt2. The RU1 varistor protects the device from mains voltage surges, and thermistors provide a "soft" turn on of the PSU and amplifier. From the secondary windings of the step-down transformer, an alternating voltage of 2x20 V is supplied to the bridge diode rectifier VD3. Capacitors C 10 ... C13 smooth out the ripples of the rectified voltages of positive and negative polarity.

A positive voltage through a polymer self-healing fuse FU3 is supplied to a voltage regulator, made on an integrated regulator DA1, a transistor VT1 and auxiliary elements. The transistor increases the load current relative to the low-current stabilizer MC7818C (maximum operating current - no more than 1 A). Diodes VD1, VD4 protect the microcircuit and the transistor from surges and interference. Resistor R5 discharges oxide capacitors after the power is turned off, which is important if no load is connected to the PSU outputs.

The negative polarity voltage regulator, made on DA2 and VT2, works in a similar way.

The voltage on the secondary windings of the step-down transformer is chosen so that at a nominal mains voltage of 220 V and the maximum volume of the amplifier, the thermal power dissipated by the transistors does not exceed 10 ... 15 W (each). The MC7818C and MC7918C microcircuits stabilize the output voltages with a minimum difference between the input and output voltage of 2 V.

This PSU is designed to work with a 5-channel UMZCH, one of the channels of which is made on two TDA2030A connected in a bridge circuit (Pout = 36 W). It should be noted that 6-channel "computer" active acoustic systems of industrial production are often equipped with such amplifiers for 5 ICs. Let's calculate the maximum output power of such an UMZCH:

Рвых=14,4+36,1=56+36=92 (Вт).

Taking into account the fact that the supply voltage usually does not exceed ±15 V, which drops to ±10 at high volume. 12 V, the real output total power of such an amplifier will be only about 52 W, and by no means the "cleanest" sound. Therefore, in order for the UMZCH to show everything that it is potentially capable of, it must be fed with stabilized voltages.

In the design, you can use a power transformer with an overall power of 250 W (for a 5-channel amplifier). A power transformer convenient for disassembly from an old domestic TV series UPIMTST-61/67 ("thyristor" TV) is suitable. All secondary windings from such a transformer are removed. It is desirable to leave the copper screen, it is electrically connected to a common wire.

The secondary windings are wound with copper winding wire 1,4 ... 1,6 mm (do not confuse with the "yellow" aluminum winding wire). The number of turns of both halves of the secondary winding should be the same, it is determined by counting the number of turns of the filament winding (6,3 V) intended to power the kinescope cathode heater.

You can also use other step-down transformers with sufficient overall power and secondary winding voltage 2x19...21 V (idling at rated mains voltage).

Thermistors with negative. TCS type SCK103 can be replaced by any similar ones with a resistance of 5,6 ... 18 Ohm at room temperature.

Thermistors from computer PSUs are suitable. Varistor MYG20-471 can be replaced with FNR-20K470, FNR-14K470. Fixed resistors - MLT, OMLT, C1-4, C2-23 or similar imported ones. Non-polar capacitors - ceramic or film for an operating voltage of at least 50 V.

Capacitors for an operating voltage of 25 V can be installed at the outputs of the stabilizers. Capacitor C1 is a film capacitor, for an operating voltage of at least 630 V (250 V AC). Four oxide capacitors with a capacity of 6800 uF each can be replaced by two with a capacity of 10000 ... 15000 uF.

It is undesirable to use domestic high-capacity capacitors K50-18 because of their high leakage current and large dimensions. In place of capacitors C10 ... C13, I used small-sized aluminum oxide capacitors (6800 uFx50 V), removed from the power supply unit of old Epson dot-matrix printers.

The KBU6M diode bridge must be installed on a ribbed or needle-shaped duralumin heat sink with a cooling surface area of ​​approximately 100 cm2.

In some cases, the heat sink for the VD3 can be a metal case or amplifier chassis. Instead of such a diode bridge, you can use RS603, KBU6D, RS803, BR81, KVRS804 (the first digit indicates the maximum operating current - 6 or 8 A). Instead of a diode bridge, four P600G or KD213 diodes can be used. included in the bridge circuit. Diodes 1N5401 can be replaced by any of the series 1N5400, 1N5408, KD226, KD411 ... KD257.

Instead of the MC7818C chip (voltage stabilizer of positive polarity), you can take any of the xx7818, xx78M18 series, instead of the MC7918C (negative polarity voltage stabilizer) - any of the xx7918, xx79M18 series (pay attention to the different pinout of these microcircuits). Each chip is installed on its own heat sink with a cooling area of ​​about 8 cm2.

The TIP2955 transistor can be replaced with MJ2955, KT739A, 2T818A KT818GM, the TIP3055 transistor - with 2N3055, KT738A, 2T819A, KT819GM. Suitable transistors with a base current transfer coefficient of at least 30 at a collector current of 1 A. When replacing, it should be borne in mind that among powerful domestic transistors offered by retail, there is a very large percentage of substandard ones, especially among those released after 1989.

Both transistors are installed through mica spacers on a common ribbed duralumin heat sink with a base size of 175x100x5 mm (according to the size of the board). If the transistors, when the amplifier is operating at maximum volume, heat up by more than 75 ° C, it is necessary to use either a more efficient heat sink or forced airflow.

Two-winding choke L1 - industrial, from the mains filter of the "Panasonic" CRT TV (with a large screen diagonal). Any similar two-winding inductor for an operating current of at least 1 A with an inductance of each winding of at least 0,5 mH is suitable. In the absence of such a choke, it can be made independently by winding it on two K32x20x9 ferrite rings glued together. HM3000 30 turns of double-folded mounting wire with a copper cross section of 0,5 mm2. The ESB99902S power button, designed for switching the mains voltage of 250 V at a current of 5 A, can be replaced by any similar one.

A drawing of the printed circuit board of the device is shown in Fig.2. It contains all the elements related to the rectifier and stabilizers, except for powerful transistors.

Before manufacturing a board, you should check the placement of existing parts on it, especially oxide capacitors. The heat sink flanges of the TDA2030 microcircuits are connected to the "minus" of the power supply, and all microcircuits, in principle, can be installed on a common heat sink without insulating gaskets. True, such an arrangement will lead to some increase in UMZCH distortion due to non-optimal wiring of the microcircuit power circuits. In general, it is desirable that the microcircuit housings be isolated from one another, and a "own" pair of blocking capacitors with a capacity of 470 ... 1000 microfarads is installed near the power leads of each IC.

Instead of manufacturing a stabilized power supply, if necessary, you can go the other way and replace the UMZCH TDA2030 microcircuits with more powerful analogues, for example, TDA2050, powered by an unstabilized source (± 25 V, while Pout = 35 W).

In conclusion, one more note. As protective diodes at the output of such microcircuits, "low-frequency" diodes 1N4001, KD208A or similar are usually installed. As practice has shown, such diodes are often damaged, "taking away" the protected microcircuit. In their place, it is desirable to install "fast" rectifier diodes, for example, UF4004, KD226E, 1N4935, 1N5393.

Author: A.Butov, village of Kurba, Yaroslavl region

See other articles Section Surge Protectors.

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 Dog 31000 years old 14.01.2010 An international expedition of archaeologists unearthed the remains of a 31-year-old dog in a Belgian cave. This is 18 years older than previously known evidence of dog domestication by humans, and approaches the time of dog domestication calculated by geneticists - 40 years since the dog split from its wild ancestors. The calculation was made according to the known rate of gene change by comparing the genome of a modern dog with the genome of its ancestors.

Other interesting news:

▪ DC-DC converter SPB05 5W in SIP package

▪ Malarial mosquitoes sense toxins

▪ Cloning of ancient animals is discussed by Russian scientists

▪ Robot sloth

▪ Multi-channel network encoder with a total throughput of 100 Gbps

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 Stereograms from patterns. Encyclopedia of visual illusions

▪ article Why did the West get scared of Khrushchev's Kuzka's mother? Detailed answer

▪ article Machine from a hand drill. home workshop

▪ article Thermal sensors. Encyclopedia of radio electronics and electrical engineering

▪ article A simple loudspeaker with an acoustic labyrinth. 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