Sharp LC-50LE771E Service Manual ▷ View online
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Figure : Pin description.
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Table: Pin functions.
Table: Recommended operating conditions.
B. HEAD-PHONE AMPLIFIER STAGE
Head-phone is a SoC (single on chip) configuration in mainboard, Design scheme is
shown in figure 3.
Figure: Head-phone
B. HEAD-PHONE AMPLIFIER STAGE
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C. SUBWOOFER AMPLIFIER STAGE
1. PREAMPLIFIER (DRV632)
a. Description
The DRV632 is a 2-VRMS pop-free stereo line driver designed to allow the removal of the
output dc-blocking capacitors for reduced component count and cost. The device is ideal for
single-supply electronics where size and cost are critical design parameters.
Designed using TI’s patented DirectPath™ technology, The DRV632 is capable of driving
2 VRMS into a 10-kΩ load with 3.3-V supply voltage. The device has differential inputs and
uses external gain-setting resistors to support a gain range of ±1 V/V to ±10 V/V, and gain
can be configured individually for each channel. Line outputs have ±8-kV IEC ESD
protection, requiring just a simple resistor-capacitor ESD protection circuit. The DRV632 has
built-in active-mute control for pop-free audio on/off control. The DRV632 has an external
undervoltage detector that mutes the output when the power supply is removed, ensuring a
pop-free shutdown.
Using the DRV632 in audio products can reduce component count considerably compared
to traditional methods of generating a 2-VRMS output. The DRV632 does not require a power
supply greater than 3.3 V to generate its 5.6-Vpp output, nor does it require a split-rail power
supply. The DRV632 integrates its own charge pump to generate a negative supply rail that
provides a clean, pop-free ground-biased 2-VRMS output.
The DRV632 is available in a 14-pin TSSOP.
b. Features
• Stereo DirectPath™ Audio Line Driver
– 2 Vrms Into 10 kΩ With 3.3-V Supply
• Low THD+N < 0.01% at 2 Vrms Into 10 kΩ
• High SNR, >90 dB
• 600-Ω Output Load Compliant
• Differential Input and Single-Ended Output
• Adjustable Gain by External Gain-Setting Resistors
• Low DC Offset, <1 mV
• Ground-Referenced Outputs Eliminate DC-Blocking Capacitors
– Reduce Board Area
– Reduce Component Cost
– Improve THD+N Performance
– No Degradation of Low-Frequency Response Due to Output Capacitors
• Short-Circuit Protection
• Click- and Pop-Reduction Circuitry
• External Undervoltage Mute
• Active Mute Control for Pop-Free Audio On/Off Control
• Space-Saving TSSOP Package
C. SUBWOOFER AMPLIER STAGE
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Figure: PW package.
Table: Pin functions.
Table: Recommended operating conditions.
2. SUB WOOFER MAIN AMPLIFIER (TPA3112D1)
a. Description
The TPA3112D1 is a 25-W efficient, Class-D audio power amplifier for driving a bridge
tied speaker. Advanced EMI Suppression Technology enables the use of inexpensive ferrite
bead filters at the outputs while meeting EMC requirements. SpeakerGuard™ speaker
protection system includes an adjustable power limiter and a DC detection circuit. The
adjustable power limiter allows the user to set a "virtual" voltage rail lower than the chip
supply to limit the amount of current through the speaker. The DC detect circuit measures the
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