HOME     STORE     BLOG     SCHEMATICS     TUTORIALS     DOWNLOADS     CONTACT

Low Power Stereo Amplifier TDA2822
 
Low Power Stereo Amplifier TDA2822


 

Low Power Stereo Amplifier TDA2822

 


Here's low power stereo amplifier built around TDA2822 chip. Many people may have heard of the TDA2822 before, but for those who haven't, it is a small power amplifier that will drive two channels. It is usually in an 8-pin DIL package, but older versions I have seen are 14-pin or similar (there are datasheets for both variants). For simplicity though, my circuits show schematics for the 8-pin DIL package. The datasheet is here, provided by ST. This article is based along the usage of the TDA2822M variant of the chip series as it is commonly available. The TDA2822 is similar, but has slightly more pins so is less used.


Low Power Stereo Amplifier TDA2822

I have seen the TDA2822 used in commercial offerings too, based on a circuit very similar to the schematic shown. An old ghetto Blaster used this chip (the 14-pin version) and for a small old system, its performance is better than many cheap offerings today. I have also seen this chip in use in PC speakers, a pair I got free when I brought a computer case claimed 120W PMPO. Well I won't lie like they do, this amp is only capable of 700mW per channel from a 6V power supply into 8 ohms (should be over a watt with 12V). This amp can also function well as an amp for headphones, providing 20mW into 32 ohms from 3V. I would have used it for that purpose in my main system, but unfortunately, space was limited and all I could do was run some resistors in series with the output to cut down the volume for headphones.

So what have I done with these amps then? Well recently I have rebuilt a pair of speakers I had to be amplified with this amp. The speakers are quite large 4in speakers, but the TDA2822M will provide over a watt into each from the 12V PSU I am using. With built in transformer, these speakers easily impress more then most cheap walkman and PC speakers.

Update:

I have changed my small stereo speakers from a two TDA7052 amps to one TDA2822M amp. This is because my TDA7052 circuit eventually failed. I guess this is so because the outputs from the TDA7052 are bridged and the removal and insertion of the 3.5mm plug that I used to connect the other speaker to the one with the amplifier circuit in would short the circuit momentary. The new circuit will make use of the TDA2822M's non-bridged output which is still capable of nearly as much power (enough for the reason I built the speakers).

The other amp I built was brought as a project kit and uses a similar circuit, the advantage of course was I didn't need to build the board. I used this amp in a small (ish) FM radio. Don't ask how I made a stereo FM radio circuit because the circuit was just re-used from a rather sorry ghetto Blaster. It does have LW and MW too, but these don't work properly. The speakers are just simple elliptical speakers, but quality is bad at all, although it needs a regulated PSU because that digital clock I put in makes the amp hum if it runs off the same unregulated PSU.

Construction


The circuit is simple to construct, it can be done easily on strip-board, although I have never tried it to be honest. As always make sure that you insert the TDA2822M chip in the board the right way and please get the electrolytic capacitors the right way round, I only recently blew one up in them larger speakers I have mentioned above. Nothing else is particularly critical, the amp will happily run with the cheapest resistor and capacitors you can buy. A dual log pot is recommended because it gives simple volume adjustment. Any thing else can be added as you require, i.e. tone controls etc, but it is unlikely you will need anything else for simple systems.

The circuit also contains a power LED, which can easily be removed if not needed by omitting R3 and LD1 and also includes a dual gang volume control in the form of RV1a and RV1b.

ST Microelectronics were nice enough to also provide PCB layouts in their datasheet. The following is the stereo application of the TDA2822M fit onto a very small sized board. The only problem with this is for most of my applications the TDA2822M has been a standalone amplifier PCB which means I have wanted to include both volume control, LED's and PCB jack and power sockets. I'm sure you can also modify the layout however to fit your needs...



Note: The above image is copied directly from the datasheet and is not mine, nor is it likely to be 1:1 scale. To achieve this scale, the best idea is to print to PDF file to A4 paper.

While this is mainly a battery operated device, a power supply is easy to make too, and a circuit idea is shown below. You shouldn't need more then 1000uF for the smoothing capacitor, although capacity more won't hurt, it will just increment your parts bill. A simple EI transformer is ideal for the job and 15VA will give you more then 1A with 9V secondary wirings.

MAINS VOLTAGE IS VERY DANGEROUS AND THE FOLLOWING PSU USES IT. DO NOT WIRE IT UNLESS YOU ARE SUITABLE QUALIFIED, DEATH OR SERIOUS INJURY MAY RESULT.



On the other hand, I would recommend, especially for beginners, that you just buy a simple DC adapter (giving about 12V). This is already made and rectified, and most importantly, safe becausemains electricity is dangerous. Get one with a good current output though, I would say 100mA is the absolute minimum, although this amp runs off a 9V PP3 longer than you would expect. For those who want a bit more volume, get a 12V PSU which will provide 1A or more (although more is probably unnecessary), and connect speakers that are sensitive to it, like those elliptical speakers in my radio, or better. Small low cost speakers (especially 55mm or less) have low sensitivity, as do high quality hi-fi speakers and should be avoided unless they are necessary.

This amp can also be very portable, as before I built the radio, I used the amp in a small pair of Walkman type speakers (that were passive). Only from 3V, there was a lot more volume then having them just passive, I recall people were quite impressed (although as you can guess the tone from the speakers was poor).

Extra (simple) parts you may want to add to the schematic could be:

3.5mm jack input socket
A power switch
Batteries
2.1mm power plug (for external PSU's) - if wired correctly, this should disconnect the batteries when a plug is pushed into the socket.
Bridge Version
There is a bridge variant of this chip available in the datasheet should it be required. It is smaller still then the stereo version of the chip and should provide output levels similar to or even greater then, the TDA7052.



Again, this circuit is simply taken from the datasheet and you may need to modify it to include a single gang volume control. Please refer to the datasheet for schematics, components their values.

That's about all that can be said about this amp because so many applications are possible from it - it is very cheap too, however if you want that extra power, using two TDA7052 amps is also simple and will give you a little more power. Remember that the TDA7052 amplifiers are bridged and may not be suitable for some situations.


Low Power Stereo Amplifier TDA2822


Low Power Stereo Amplifier TDA2822






Accurate LC Meter Capacitance Inductance Meter with 16F628 and LCD
Volt Ampere Meter with 16F876 Microcontroller and LCD display
 
Accurate LC Meter

Build your own Accurate LC Meter (Capacitance Inductance Meter) and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils and inductors. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging as well as reset switch and produces very accurate and stable readings.
PIC Volt Ampere Meter

Volt Ampere Meter measures voltage of 0-70V or 0-500V with 100mV resolution and current consumption 0-10A or more with 10mA resolution. The meter is a perfect addition to any power supply, battery chargers and other electronic projects where voltage and current must be monitored. The meter uses PIC16F876A microcontroller with 16x2 backlighted LCD.

50MHz 60MHz Frequency Meter / Counter with 16F628 & LCD
1Hz - 2MHz XR2206 Function Generator
60MHz Frequency Meter / Counter

Frequency Meter / Counter measures frequency from 10Hz to 60MHz with 10Hz resolution. It is a very useful bench test equipment for testing and finding out the frequency of various devices with unknown frequency such as oscillators, radio receivers, transmitters, function generators, crystals, etc.
1Hz - 2MHz XR2206 Function Generator

1Hz - 2MHz XR2206 Function Generator produces high quality sine, square and triangle waveforms of high-stability and accuracy. The output waveforms can be both amplitude and frequency modulated. Output of 1Hz - 2MHz XR2206 Function Generator can be connected directly to 60MHz Counter for setting precise frequency output.

BA1404 HI-FI Stereo FM Transmitter
USB IO Board PIC18F2455 / PIC18F2550
BA1404 HI-FI Stereo FM Transmitter

Be "On Air" with your own radio station! BA1404 HI-FI Stereo FM Transmitter broadcasts high quality stereo signal in 88MHz - 108MHz FM band. It can be connected to any type of stereo audio source such as iPod, Computer, Laptop, CD Player, Walkman, Television, Satellite Receiver, Tape Deck or other stereo system to transmit stereo sound with excellent clarity throughout your home, office, yard or camp ground.
USB IO Board

USB IO Board is a tiny spectacular little development board / parallel port replacement featuring PIC18F2455/PIC18F2550 microcontroller. USB IO Board is compatible with Windows / Mac OSX / Linux computers. When attached to Windows IO board will show up as RS232 COM port. You can control 16 individual microcontroller I/O pins by sending simple serial commands. USB IO Board is self-powered by USB port and can provide up to 500mA for electronic projects. USB IO Board is breadboard compatible.

ESR Meter / Transistor Tester Kit
Audiophile Headphone Amplifier Kit
 
ESR Meter / Capacitance / Inductance / Transistor Tester Kit

ESR Meter kit is an amazing multimeter that measures ESR values, capacitance (100pF - 20,000uF), inductance, resistance (0.1 Ohm - 20 MOhm), tests many different types of transistors such as NPN, PNP, FETs, MOSFETs, Thyristors, SCRs, Triacs and many types of diodes. It also analyzes transistor's characteristics such as voltage and gain. It is an irreplaceable tool for troubleshooting and repairing electronic equipment by determining performance and health of electrolytic capacitors. Unlike other ESR Meters that only measure ESR value this one measures capacitor's ESR value as well as its capacitance all at the same time.
Audiophile Headphone Amplifier Kit

Audiophile headphone amplifier kit includes high quality audio grade components such as Burr Brown OPA2134 opamp, ALPS volume control potentiometer, Ti TLE2426 rail splitter, Ultra-Low ESR 220uF/25V Panasonic FM filtering capacitors, High quality WIMA input and decoupling capacitors and Vishay Dale resistors. 8-DIP machined IC socket allows to swap OPA2134 with many other dual opamp chips such as OPA2132, OPA2227, OPA2228, dual OPA132, OPA627, etc. Headphone amplifier is small enough to fit in Altoids tin box, and thanks to low power consumption may be supplied from a single 9V battery.
 

Arduino Prototype Kit
RF Remote Control 433MHz Four Channel
 
Arduino Prototype Kit

Arduino Prototype is a spectacular development board fully compatible with Arduino Pro. It's breadboard compatible so it can be plugged into a breadboard for quick prototyping, and it has VCC & GND power pins available on both sides of PCB. It's small, power efficient, yet customizable through onboard 2 x 7 perfboard that can be used for connecting various sensors and connectors. Arduino Prototype uses all standard through-hole components for easy construction, two of which are hidden underneath IC socket. Board features 28-PIN DIP IC socket, user replaceable ATmega328 microcontroller flashed with Arduino bootloader, 16MHz crystal resonator and a reset switch. It has 14 digital input/output pins (0-13) of which 6 can be used as PWM outputs and 6 analog inputs (A0-A5). Arduino sketches are uploaded through any USB-Serial adapter connected to 6-PIN ICSP female header. Board is supplied by 2-5V voltage and may be powered by a battery such as Lithium Ion cell, two AA cells, external power supply or USB power adapter.
200m 4-Channel 433MHz Wireless RF Remote Control

Having the ability to control various appliances inside or outside of your house wirelessly is a huge convenience, and can make your life much easier and fun. RF remote control provides long range of up to 200m / 650ft and can find many uses for controlling different devices, and it works even through the walls. You can control lights, fans, AC system, computer, printer, amplifier, robots, garage door, security systems, motor-driven curtains, motorized window blinds, door locks, sprinklers, motorized projection screens and anything else you can think of.
 

Electronics-DIY.com © 2002-2024. All Rights Reserved.