Circuit audio power amplifier using integrated lm4782 overtureTM for three channels of 25W with mute and stand-by LM4782 is audio amplifier of three channels capable to supply 25W of potency for channel.
LM4782 uses the system of protection of National Self Peak Instantaneous Temperature (˚Ke) (SPiKeTM). Spike protects the exit of the lm4782 of on tension on load, short of the source for gnd, temperature protection and picks instantaneous of temperature. Each amplifier of the lm4782 has a mute circuit and internal stand-by, that can be controlled by logic it expresses. LM4782 can be configured to be used in bridge or in parallel way without complications, it exists several ways to use integrated him. To know more on spike it seeks for AN-898 in the site national.com . Description of the operation of the circuit of the amplifier with lm4782
The circuit described here it is treated of the application suggested by the national semiconductors for an amplifier of potency of three channels with having integrated lm4782. To determine the heat-sink to be used it sees the datasheet of the lm4782.
In the way stand-by the drain of current of the source VCC is less than 30µA for all amplifiers and chain drained of the source VEE is typically of 8mA. Bypassing Capacitors
To eliminate possible oscillations or instability in low frequency high frequency either is used a capacitor electrolytic or of tantalum to absorb variations in low frequency and a ceramic capacitor to prevent feedback in discharges frequencies. those components are placed in the power lines. Filter high raisin
The combination of it Laughs with ci it creates a filter high raisin. The frequency answer is determined by those two components. The point of -3dB can be found using the equation below: fi=1/(2ÀRiCi) (Hz)
If a capacitor of blockade dc be used, there is another filter it passes discharge servant with the combination of Cin and Rin. When great values of Rin are used it can happen oscillations in the exit.
To determine the type of the heat-sink and other assembly configurations it sees the datasheet of the lm4782. Source for the circuit
That proposed circuit requests a symmetrical source of +-25volts that is capable of ?¤ “teão is necessary that is regulated. Just use a good transformer, rectificators and great capacitors of filter of at least 10000µF. The transformer uses transformer torodal preferably, they exist virtual stores that sell transformers and they dispatch for the whole brazil. Schematic of the circuit of the potent amplifier with lm4782 Orijinal görüntüsünü görmek için buraya tıklayın. 524x566 px. Printed circuit board (couple face) side of the it welds suggested by the national for assembly of the potent amplifier of three channels Circuit board (couple face) printed side of the components suggested by the national for assembly of the amplifier Assembly of the components of the amplifier in the board silkscreen of the board of the amplifier It lists of material for assembly of the amplifier
Name value tolerance type /description RIN1,RIN2,RIN3 33kP6; 5% 1/4 watt RB1,RB2,RB3 1kP6; 1% 1/4 watt RF1,RF2,RF3 20kP6; 1% 1/4 watt Ri1,Ri2,Ri3 1kP6; 1% 1/4 watt RSN1,RSN2,RSN3 4.7P6; 5% 2 watt ID 2.7P6; 5% 1/4 watt RV 5.1kP6; 5% 1/4 watt CIN1,CIN2,CIN3 1µF 10% Film metallic polyester CN1,CN2,CN3 15pF 20% Ceramic Ci1,Ci2,Ci3 68µF 20% Ceramic Radial / 35V CSN1,CSN2,CSN3 0.1µF 20% Ceramic CV 0.1µF 20% Ceramic CS1,CS2 0.1µF 20% Ceramic CS3,CS4 10µF 20% Radial Ceramic /50V CS5,CS6 2,200µF 20% Ceramic Radial / 50V S1,S2
Key SPDT (on-on) J1,J2,J3
PCB Montage RCA Jack J5,J7,J9,J11
PCB Banana Jack – Black J4,J6,J8,J10,J12
PCB Banana Jack – Red VZD 5.1V
Zener Diode 1W U1 LM4782
TO-220 For more information to do download of the datasheet of the lm4782
Ahmet UZUN on 18 Mar 12" Precision Power Supply © 1986 Doug Bedrosian and 2010 Tony van Roon "This Precision Power Supply is a nice addition on your workbench as primary, or in my case, a supplementary power supply. With zero to 40V and 2A with adjustable current limiting it will surely gets lots of use on your bench. On average the most amperage for a power supply someone needs is around two or three amps. The sensitivity for current limiting is fully adjustable. Have fun building!" Introduction: Test instruments are considered to be some of the most useful tools available when constructing a project. They are also considered to be the most expensive tools one could buy. For instance, a power supply of any quality and usefulness can range from several hundred dollars to several thousand dollars. The alternative to buying a power supply is to build one. The power supply in this article has a voltage range from 0 to 40V and a current range from 0 to 2 amps with current limiting set by the user. The quality of the supply is determined by the time and care the builder takes while constructing it. How It Works: The power supply is best understood when divided into separate parts. The first parts to look at are the two power supply sections. The output supply section consists of XFMR1, Br1, C1, and C2. They supply the appropriate voltage and current required at the output. The IC supply consists of XFMR2, Br2, and C3. The two power supply sections must be separate from each other because a floating ground is required for IC1. The next section is the voltage control. RV1 and R2 determine the operating point of a constant current source out of pin 3 of IC1. By varying RV1 the maximum output voltage will be set. Pins 8 and 9 are inputs to a high gain differential amplifier contained in IC1. By adjusting potentiometer P1 the voltage at pin 8 will vary; this will cause the voltage at the output to change until it is equal to the voltage at pin 8. Due to the high gain of the differenti