All of you may know about many different single chip audio amplifiers, some of which are very popular like LM384, LM386 from National Instrumentation (NI). You will find these chips in many easy-to build audio amplifier circuits which need additional components like resistors, capacitors as well as some time inductors.
But what if you get a single chip audio amplifier of 3W output that does not require any external components? Yes, it’s TDA7056 chip from NXP (Philips) semiconductors.
This chip does not require any external components. It only needs two capacitors for biasing and one pot for volume control (and that’s also optional). Just apply audio input and connect 1W @ 8Ω (or 3W @ 16Ω) loud speaker to output terminals and that’s all. This chip is widely used in different audio amplifier circuits for audio recorders and players, MP3 players and other such devices. Its major features are:
• Bridge Tide load working principle
• Supply voltage range : 3 V to 18 V
• Gain : 40 dB
• No external components required
• No switch-on or switch-off clicks
• Good overall stability
• Low power consumption
• No external heat sink required
It uses Bridge-Tied-Load (BTL) principle which can deliver an output power of 1W into an 8 Ω load with a power supply of 6 V and 3W power into 16 Ω load with a power supply of 11 V.
Fig. 1: Image showing TDA7056 based Audio Amplifier Circuit designed on a breadboard
So here the given circuit demonstrates how to use TDA7056 chip for audio amplification application. But before that first let us understand the pin diagram of TDA7056.
TDA7056 pin diagram:
|
Pin num |
Pin name |
Pin function |
|
1 |
NC |
Not used |
|
2 |
Vcc |
Connect 3 to 18 V DC supply with two external capacitors 220µF and 100 nF for biasing |
|
3 |
input |
Connect audio signal input (through pot or fixed resistor of 5K) |
|
4 |
Signal ground |
Connect with audio signal ground |
|
5 |
NC |
Not used |
|
6 |
Output 1 |
Output terminal 1 |
|
7 |
Supply ground |
Connect with supply ground for biasing |
|
8 |
Output 2 |
Output terminal 2 (connect speaker (load) between output terminals 1 & 2) |
|
9 |
NC |
Not used |
Circuit description:
The circuit is built using only two chips, namely melody generator UM66 and audio amplifier TDA7056 along with few additional capacitors like resistors, pot and capacitors. For giving audio input, the best possible choice is melody generator chip UM66 that requires around 3 V input given by voltage divider network build using R1 and R2. The 5 V input is reduced to around 3 V. Output of UM66 is connected to input (3) of TDA7056 through 5 K pot R3. R3 is used for volume control. Vcc pin (2) is given 12 V supply along with two capacitors connected as shown in the above figure. A 3W, 16Ω loud speaker is connected to output terminals 6 and 8. The circuit uses two supplies 5 V and 12 V for its operation.
Circuit operation:
• When switch is pressed momentarily the UM66 chip gets input
• It generates melody output tone that is fed to TDA7056 through pot
• TDA7056 chip amplifies this audio tone input from UM66 and produces melody sound from speaker. The output is around 3 W
• The pot limits input signal to TDA7056 and thus provide volume control. So by varying pot volume of output, the tone can also be adjusted.
The pot limits input signal to TDA7056 and thus provides volume control. So by varying pot volume of output tone can be adjusted.
Circuit Diagrams
Project Video
Filed Under: Electronic Projects
Filed Under: Electronic Projects
Questions related to this article?
👉Ask and discuss on EDAboard.com and Electro-Tech-Online.com forums.
Tell Us What You Think!!
You must be logged in to post a comment.