Sanyo LA4440 Integrated Circuit has two audio amplifier
which can be used in two modes, 2 channel stereo amplifier and mono bridged
amplifier.
Single mono bridged Circuit Schematic
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LA4440 IC supports 6 watts * 2 channel stereo amplifier and
19 * 1 channel bridged mono amplifier.
LA4440 Power Amplifier is high performance IC. The IC
amplifier has low distortion and has built in
Thermal protector, Overvoltage, surge voltage protector,
Pin-to-pin short protector. LA4440 also has a built in muting function and has
good ripple rejection of 46dB and small residual noise.
IC can drive both 8 ohm and 4 ohm speakers. Can be used to build high quality audio board
or stereo system of Computer, Pc, Laptops and mobile phone, media players and
anything which has audio output for speakers.
This IC support a high voltage gain of 53.5 dB, this means
that even with low signal you can get a better sound quality.
This integrated circuit can produce 6watts output into 4ohm
load at 13.2v supply when signal of 5milli volt is applied and can produce 19watts
in bridged mode.
To obtain good sound quality, we must employ properly
regulated power supply.
We need 12-14 volts 4 amperes properly regulated power
supply for Bridged mono channel 19 watts amplifier and incase of stereo dual
channel 6 * 2 watts, we need 2.5 Amperes .
While designing the power supply for LA4440 one should pay
attention to these things.
At least 25v capacitor should be
used in power supply.
Diode Bridge should be capable of
Providing 6 Ampere. Or it should be manual made by using 6 ampere diodes for
19watts amp and incase of 6 watts * 2 amplifier, it should be able to provide 3
amperes. Higher Capacity Bridge will not hurt.
Use 7*1000 microfarad capacitor
instead of 1 6800 microfarad capacitor. Or Use 3*2200 microfarad capacitor. Each
channel should have at 6000 microfarad capacitance at power supply.
Please do not use local cheap brand capacitors,
use Samsung, nichion, rubycon, or at least use klyrton .
Use mental film register instead
of carbon film, mental film register have better sonic quality.
Use malyar or polyester capacitor
instead of ceramic and electrolyte capacitor as they have low leakage and gives
better sound quality.
This simple and inexpensive integrated
circuit can be used for improving sound quality. You can do the project
yourself and can build an audio board on LA4440 for your needs. This power amplifier
address low power of audio devices in at cheap price.
All you need is power supply,
pair of speakers, a little soldering skills and enclosures, you will get a good
amplifier for your computers, better than what you can but at this price range
in the market.
Description of used external parts :-
C1 (C2) · Feedback capacitor : The low cutoff frequency depends on this capacitor.
If the capacitance value is increased, the starting time is delayed.
C3 (C4) · Bootstrap capacitor : If the capacitance value is decreased, the output at low frequencies goes lower.
C5 (C6) · Oscillation preventing capacitor : Polyester film capacitor, being good in temperature characteristic,
frequency characteristic, is used.
The capacitance value can be reduced to 0.047mF depending on the stability of the board.
C7 (C8) · Output capacitor : The low cutoff frequency depends on this capacitor.
At the bridge amplifier mode, the output capacitor is generally connected.
C9 · Decoupling capacitor :Used for the ripple filter. Since the rejection effect is saturated at a certain
capacitance value, it is meaningless to increase the capacitance value more than required. This capacitor,
being also used for the time constant of the muting circuit, affects the starting time.
R1 (R2) · Filter resistor for preventing oscillation.
R3 (R4) · Resistor for making input signal of inverting amplifier in Voltage Gain Adjust at Bridge Amplifier
Mode (No. 1).
R5 · Resistor for adjusting starting time in Voltage Gain Adjust at Bridge Amplifier Mode (No. 2)
C10 · Capacitor for preventing oscillation in Voltage Gain Adjust at Bridge Amplifier Mode (No. 2)
C11 · Power source capacitor.
R6 (R7) · Used at bridge amplifier mode in order to increase discharge speed and to secure transient stability.
Power supply schematic .
Single IC stereo Circuit Schematic
Single IC stereo pcb diagram
Description of used external parts :-
C1 (C2) · Feedback capacitor : The low cutoff frequency depends on this capacitor.
If the capacitance value is increased, the starting time is delayed.
C3 (C4) · Bootstrap capacitor : If the capacitance value is decreased, the output at low frequencies goes lower.
C5 (C6) · Oscillation preventing capacitor : Polyester film capacitor, being good in temperature characteristic,
frequency characteristic, is used.
The capacitance value can be reduced to 0.047mF depending on the stability of the board.
C7 (C8) · Output capacitor : The low cutoff frequency depends on this capacitor.
At the bridge amplifier mode, the output capacitor is generally connected.
C9 · Decoupling capacitor :Used for the ripple filter. Since the rejection effect is saturated at a certain
capacitance value, it is meaningless to increase the capacitance value more than required. This capacitor,
being also used for the time constant of the muting circuit, affects the starting time.
R1 (R2) · Filter resistor for preventing oscillation.
R3 (R4) · Resistor for making input signal of inverting amplifier in Voltage Gain Adjust at Bridge Amplifier
Mode (No. 1).
R5 · Resistor for adjusting starting time in Voltage Gain Adjust at Bridge Amplifier Mode (No. 2)
C10 · Capacitor for preventing oscillation in Voltage Gain Adjust at Bridge Amplifier Mode (No. 2)
C11 · Power source capacitor.
R6 (R7) · Used at bridge amplifier mode in order to increase discharge speed and to secure transient stability.
Power supply schematic .
Single IC stereo Circuit Schematic
Single mono bridged Circuit Schematic
I have transformers, LA4440 circuit boards (pcb), heatsinks for sale at cheap price in India. Email me or message me if you want to buy them . I have upgraded my audio system even more powerful IC hence I am selling my old IC and stuff .
