The La4440 is the most popular dual channel amplifier IC, different types of amplifier circuits are available using la4440 IC, most of them are low cost and reliable at work, so in this article, we are going to show you bridge amplifier using la4440 amplifier circuit.
At La4440 datasheet having 3 different circuits, but does not include the PCB layout. Some of the websites on the internet have created la4440 PCBs, but I am not satisfied with those layouts. So we just created a professional PCB layout of la4440 amplifier circuits and it will be made and tested, the testing video will be included at the end of this article.
La4440 amplifier circuit
The main part of this amplifier is la4440 IC, the amplifier IC will produce 6w in stereo mode and 19w in bridge mode.
The maximum power of la4440 is 18W and the minimum is 12W.
The C1 and C2 are electrolyte-type capacitors that are used to reduce the noise, the staring time is delayed due to varying the capacitor value, and the capacitor is called a feedback capacitor.
The C3 (C4) capacitor is called the Bootstrap capacitor, decrease in capacitance value will results in the output at low frequencies goes low.
The C5 (C6) polyester film capacitor is used to preventing oscillation, they are being good at temperature characteristics and frequency characteristics.
The capacitance value can be reduced to 0.047µF depending on the stability of the board.
The C7 (C8) Output capacitor is used to cutoff low-frequency signals.
When the circuit works in bridge amplifier mode, the output capacitor is generally connected, C9 Decoupling capacitor, Used to filter ripples, since the rejection effect is saturated at a certain.
At this point, meaningless to increase the capacitance value more than required. This capacitor, which is also used for the time constant of the muting circuit, will affect the starting time.
The resistors R1 (R2) are Filter resistors for preventing the oscillation.
The R5 Resistor is for adjusting starting time in Voltage Gain Adjust at Bridge, Amplifier Mode (No. 2)
And C10 Capacitor is for preventing oscillation in Voltage Gain Adjust at Bridge Amplifier Mode (No. 2)
Then the C11 capacitor is used as the Power source.
And last R6 (R7) resistor Used at bridge amplifier mode to increase discharge speed and to secure transient stability.
la4440 amplifier components list
|104/50V||Mylar Cap||C8, C11, C12|
|1000uF||Electrolytic Cap||C6, C9, C10|
|100uF||Electrolytic Cap||C5, C7|
|4R7||Resistor 1/4W||R7, R8|
|47uF||Electrolytic Cap||C1, C4|
|470R||Resistor 1/4W||R5, R6|
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