Power amplifier BTL

Audio amplifiers operate either in a BTL (bridged) or single-ended ("normal") configuration. In the single-ended setup, the output lead goes to the "hot" or "+" side of the load (speaker or speaker box since we are talking audio) and the "-" or "negative" side of the load is tied to a common ground shared with the amplifier. In the BTL configuration, one amp is connected to the "+" side of the speaker (load) and a second amp is connected to the "-" side of the load. For this to work, the output signal from the second amplifier must be a "mirror image" (identical in every respect, but 180 degrees out of phase) of the output from the first amp. The BTL configuration is most often seen in low-voltage, battery-powered applications (like cell phones or "walkman" type personal tape or cd players etc) or in automotive applications over about 10 watts per channel.

In the BTL configuration, each amp drives half the load impedance. With the signals being out of phase, the voltage swing across the load appears to be doubled, and with each amp driving half the impedance the current is doubled. In theory the bridged pair will produce 4 times the power into the load that either amp acting alone could provide. In reality it seldom works that well.

This is an power amplifier circuit of a BTL system, which comprises a first op-amp chip 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. (end of abstract)

List Componet:
R1, R2,R3, R4, R6..................... 10kOhm.
R3............................................. 20kOhm.
C1, C2, C3, C4........................... 10µF.
Catu daya (VCC) ±12 V.



source : http://elektroarea.blogspot.com

300 Watt OCL audio amplifier circuit

This is a 300W power amplifier OCL circuit that the circuit has been stout kit on the market. If you are fanatical about the use of transistors 2N3055 and MJ2955 jengkol then this circuit is the answer. This power amplifier OCL circuit delivering a blasting 300 watts to a 4 Ohm speaker.

The amplifier circuit is very Cheapest and cans be powered from 24 to 32 V/5A dual power supply. You must try this circuit. Its working great. Because 4 transistors (2 x 2n3055 and mj 2955) on the final amplifier will of some very hot then add the aluminum finned cooler and the fan so That the transistor is not too high temperatures

SOURCE : http://skema-amplifier.blogspot.com

300W Power amplifier for subwoofer

The 300W Amplifier circuit is shown it is a reasonably conventional design. Connections are provided for the Internal SIM, and filtering is provided for RF protection (R1, C2). The input is via a 4.7uF bipolar cap, as this provides lots of capacitance in a small size. Because of the impedance, little or no degradation of sound will be apparent. A polyester cap may be used if you prefer - 1uF with the nominal 22k input impedance will give a -3dB frequency of 7.2Hz, which is quite low enough for any sub.

Continuous power into 8 ohms is typically over 150W (250W for ±70V supplies), and it can be used without additional transistors at full power into an 8 ohm load all day, every day. The additional transistors are only needed if you want to do the same thing into 4 ohms at maximum supply voltage

Although I have shown MJL4281A and MJL4302A output transistors, because they are new most constructors will find that these are not as easy to get as they should be. The alternatives are MJL3281/ MJL1302 or MJL21193/ MJL21194.

Because this amplifier circuit operates in "pure" Class-B (something of a contradiction of terms, I think), the high frequency distortion will be relatively high, and is probably unsuited to high power hi-fi. At the low frequency end of the spectrum, there is lots of negative feedback, and distortion is actually rather good, at about 0.04% up to 1kHz. My initial tests and reports from others indicate that there are no audible artefacts at high frequencies, but the recommendation remains.

Circuit from: www.sound.westhost.com

Stereo audio amplifier with TDA 2004

The TDA2004A is a class B dual audio power amplifier (10 + 10W STEREO AMPLIFIER) in MULTIWATT package specifically designed for car radio applications.
stereo amplifiers are easily designed using this device that provides a high current capability (up to 3.5A) and that can drive very low impedance loads (down to 1.6 ohm).
Its main features are :
Low distortion, Low noise, High reliability of the chip and of the package with additional safety during operation.
space and cost saving : very low number of external components,very simple mounting system with no electrical isolation between the packageand the heatsink.
you can see the schematic circuit for amplifier aplication below:

with this circuit you can easily boost your audio level, from your stereo walkman, Ipod, tuner, MP3 or MP4 player, portable receiver, laptop or PC.
PIN connection of TDA 2004 is described in this picture:

The maximum operating DC voltage on the TDA2004A is 18 V.
However the device can withstand a DC voltage up to 28V with no damage.
this information above is based from datasheet TDA2004A issued by SGS-Thomson Microelectronics

Source:http://quazen.com