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150W MP3 Car Amplifier
150W MP3 Car Amplifier Circuit : Youssef Bouterfes
Email : ybouteras123@yahoo.fr
Block Diagram:
Here, it is a diagramm of an active loudspeaker. The LF353 of, National Semiconductor, is going to split audio signal into three bands. SANYO'S LA47536 is going to amplify these signals. In stereo mode, we shall have the action of eight high speakers who are going to create a very important sound pressure.
Three Band Active Tone Control:
Description :
LF353 Wide Bandwidth Dual JFET Input Operational Amplifier
General Description
These devices are low cost, high speed, dual JFET input operational amplifiers with an internally trimmed input offset voltage (BI-FET II technology). They require low supply current yet maintain a large gain band width product and fast slew rate. In addition, well matched high voltage JFET input devices provide very low input bias and offset currents. The LF353 is pin compatible with the standard LM1558 allowing designers to immediately upgrade e the overall performance of existing LM1558 and LM358 designs. These amplifiers may be used in applications such as high speed integrators, fast D/A converters, sample and hold circuits and many other circuits requiring low input offset voltage, low input bias current, high input impedance, high slew rate and wide bandwidth. The devices also exhibit low noise and offset voltage drift. (National Semiconductor)
Features : Internally trimmed offset voltage: 10 mV Low input bias current: 50pA Low input noise voltage: 25 nV Low input noise current: 0.01 pA Wide gain bandwidth: 4 MHz High slew rate: 13 V/us Low supply current: 3.6 m High input impedance: 1012. Low total harmonic distortion : <> Power Amplifier :
When the amplifier is installed behind in the suitcase, we shall need a switch works stop. The LA47536 possesses a function stand by in it pin4. This pine require a small tension superior to 2V in start up the amplifier. Transistor Q1 and Q2 makes the function of walking stop for distance. When the driver activates the left indicator, either light the back fires or press on the brake , lamps rear ignite driving Q2 who he even made to drive Q1 who applies a tension > 2V on it pin4. Overview
LA47536 Four-Channel 45 W BTL Car Audio Power Amplifier
The LA47536 is a 4-channel BTL power amplifier IC developed for use in car audio systems. The output stage features
- A pure complimentary structure that uses V-PNP transistors on the high side and NPN transistors on the low side to provide high power and superb audio quality.
- The LA47536 includes almost all the functions required for car audio use, including a standby switch, a muting function, and each protection circuit. It also provides a self-diagnosis function (output offset detection). (Sanyo)
Functional Description
1. Standby Switch Function (pin 4)
The pin 4 threshold voltage is set to be 2 VBE. When Vst is 2.0V or higher, the amplifier will be on, and when Vst, is 0.7V or lower, the amplifier will be off. Note that pin 4 requires an operating current of at least 40uA.
2. Muting Function
The IC is set to the muted state by setting pin 22 to the ground potential. In this state, the audio output is muted. The time constant with which the muting function operates is set by an external RC circuit, and this time constant influences the pop noise that occurs when the amplifier is turned on or off.
The muting on and off times due to the recommended external component values (R=10k, C=3.3uF) are as follows.
Muting on time: 50ms
Muting off time: 20ms
3. Self-Diagnosis Function (Speaker burnout prevention)
During steady state operation, the LA47536 detects, internally, whether or not an abnormal amplifier output offset has occurred, and outputs this signal from pin 25. Applications can prevent speaker burnout and other problems by having the system microcontroller detect this pin 25 output signal and control either the standby state or the power supply. (An abnormal output offset may be caused by, for example, input capacitor leakage current.) The pin 25 signal is turned off by setting pin 1 to the ground potential.
4. Oscillator Stability
In some cases, parasitic oscillations may be induced by the PCB layout. This oscillation can be eliminated by adding the components listed below. Note that the optimal capacitor value must be verified by testing in the actual mounted state in the end product. Connect a capacitor and resistor (0.1uF and 2.2) in series between each output pin and ground.
5. Audio Quality (Low band)
The frequency characteristics in the low frequencies can be improved by making the capacitance of the input capacitors variable. The recommended capacitance is 2.2uF and smaller.
6. Protection Circuits
Do not ground the outputs with the STBY voltage at around 1.4V. Also, do not turn the IC off in the grounded state with a time constant provided for the STBY voltage.
7. Pop Noise
Although the LA47536 includes an pop noise prevention circuit, pop noise can be reduced even further by using the muting function as well. Activate the muting function at the same time as power is applied. Then, after the output DC potential has stabilized, turn off the muting function. When turning the amplifier off, first turn on the muting function and then turn off the power supply. These two methods are effective at minimizing pop noise.
Printed Circuit Boards :
Source: http://www.zen22142.zen.co.uk/Circuits/Audio/150wmp3.htm
5-Band Graphic Equalizer
5-Band Graphic Equalizer
author: YMYA electronics - IZHAR FAREED
This complete high quality, low noise 5-BAND GRAPHIC EQUALIZER circuit is based around Monolithic Linear integrated circuit LA3600 manufactured by SANYO. This circuit is very easy to build and has good Quality. You can use it with Portable component stereos, tape-recorders, radio-cassette recorders, car stereos etc...
It is On-chip one operational amplifier. 5-band graphic equalizer for one channel can be formed easily by externally connecting capacitors and variable resistors which fix fo (resonance frequency). Series connection of two LA3600’s makes multiband (6 to 10 bands) available. It is Highly stable to capacitive load. Maximum supply voltage VCC max 20V must not be exceeded. The operating voltage is in the range of 5 to 15V. Application of power with the pin-to-pin spaces shorted causes breakdown or deterioration of the IC to occur. When mounting the IC on the board or applying power, make sure that the pin-to-pin spaces are not shorted with solder, etc.
Download this circuit in PDF Source: http://www.electronics-lab.com/projects/audio/052/index.html
5A Power Supply 1.2-25V
 The core of the power supply circuit is LM338K. The scheme circuit 5A power supply with adjustable output voltage from 1.2 to 25V. Construction circuit is compact, all elements except transformer, the printed circuit. Serial element to the cooling body mounted over the aluminum-angular profile. One side of angular profile, therefore, lies between the printed circuit boards and regulators LM338K, the other side is mounted on cooling the body with one flat surface.
The regulator must be electrically isolated from the angular profile for better heat conductivity .Relationship with wires, the minimum and facilitated by the buckle on the printed circuit. Potentiometer to change the output voltage can be trimer potentiometer on a printed circuit or potentiometer on the front panel housing, with two wires connected to the printed circuit boards.
Manufacture power supply is simple and cheap.Constructed power supply is also suitable as a power supply for the benches as an experienced electrician, as well as the newcomer.
More info 5A Power Supply 1.2-25V
Voltage Inverter
This simple circuit is a good solution to the powering a dual supply op amp from a single battery problem. The circuit simply takes a positive voltage and inverts it. It uses only one 555 timer and a few other passive components, so it doesn't add much in the way of size and cost to a project.
Schematic
 Parts
R1 ---- 24K 1/4 Watt Resistor
R2 ---- 56K 1/4 Watt Resistor
C1 ---- 3300pF 25V Ceramic Capacitor
C2 ---- 47uF 25V Electrolytic Capacitor
C3 ---- 10uF 25V Electrolytic Capacitor
D1, D2 ---- 1N4148 Silicon Diode
U1 ---- 555 Timer
MISC ---- Wire, Board
Notes
1. V+ can be anywhere from 4 to 16V. -V is one volt less than V+. So for -12V output, use +13V input. The maximum current output of the circuit is about 280mA, more than enough for a few op amps.
2. For better regulation, a 79LOxx series regulator can be used.
3. A zener diode may also be used to regualte the output voltage.
Passive Crossover Network Design for Hi-Fi Speaker
Passive Crossover Network Design for Hi-Fi Speaker
Crossover network for speaker can improve the quality of the sound, reducing the distortion level caused by excessive signal beyond the speaker’s frequency response. This articles describes how you can design your own crossover networks for your Hi-Fi speaker set. Both first order and second order passive filter will be explained in this article. First order crossover network will give 6dB roll off curve for the frequency response, and the second order one will give 12dB/octave roll-off. Woover, Mid-range, and Tweeter Speakers You need a low-pass filter crossover network for woover or sub-woover, a band-pass filter for mid-range speaker, and a high-pass filter for tweeter. Sometimes when you have only two speakers in a set with a woover and a tweeter, then you need only a low-pass and high pass filters. To give a flat response, you need to set the corner frequency of each filter at the same point, so the response of will cross-over (overlapped) in the transition area of each filter band). This point is called crossover frequency point. 
The circuit configuration of the circuit is simple, as shown in the figure below. The first order crossover network is the simplest, need only a capacitor for the high pass and and an inductor for the low pass. 
Designing A Crossover Network for Two-Way Speakers System For 2-way speaker system, in case of the first order filter, you just need a capacitor and inductor. Let’s say you have a 8 ohm woover and a 8 ohm tweeter. First you have to select the crossover frequency, say 1 kHz. Then you look-up the table to find the value for the inductor to be installed in series with the woover, and the capacitor to be installed in series with the tweeter. For this case you’ll get 1.2mH for the inductor and 20uF for the capacitor. If you need a second-order filter for your crossover network, then you need to provide two caps and two inductors. Look at the second table (12dB/octave) 1 kHz, 8 ohm, and you’ll find 1.8 mH and 13uF value for the inductor and capacitor. Provide two 13uF caps and two 1.8mH inductors. One capacitor should be wired in parallel with the woover, and then connected in series with the inductor. For the tweeter, you need to wire the inductor in parallel with the tweeter, then connect the capacitor in series. Designing A Crossover Network for Three-Way Speakers System For three-way speaker system, you need to define the first crossover point f1 for transition between low frequency and mid frequency, and the second crossover point f2 for the transition between mid frequency and the high frequency. Let say you have an 8 ohm woover, 8 ohm mid-range speaker, and an 8 ohm tweeter. Let’s define the crossover frequency f1=500Hz and f2=10KHz. If you want a first order filter (6dB/octave roll-off), look at the table for 200Hz, 8 ohm. You’ll find a 9mH value for the inductor. Connect this inductor to your woover in series. For the mid-range speaker, you need a capacitor and an inductor to be wired in series. Look the value of capacitor using the f1 (200Hz), and look the value for the inductor using f2 (10 kHz). You’ll need a 70uF capacitor and a 0.18mH inductor to be wired in series with the mid-range speaker. For the tweeter, you have to choose the capacitor value for f2 (10 kHz) at 8 ohm, a 1.4 uF capacitor will be needed. For the second order filter (12dB/octave roll-off), f1 (200 Hz) should be used for selecting the capacitor-inductor pair for the woover. For the tweeter, capacitor-inductor pair should be selected based on f2 (10 kHz). For the mid-range, there a two pairs of caps-inductor, i.e. L1-C1 and L2-C2 (see the last circuit wiring schematic in the figure). The first pair (Li-C1) should be chosen based on f1 (200 Hz) and the second pair (L2-C2) should be based on f2 (10 kHz).
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