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Philips Semiconductors
8. Functional description
8.1 General
9397 750 13356
Preliminary data sheet
Table 3:
Pin description
Symbol Pin
TDA8920BTH TDA8920BJ
SGND1
11
V
12
SSA1
PROT
13
V
14
DDP1
BOOT1
15
OUT1
16
V
17
SSP1
STABI
18
n.c.
19
V
20
SSP2
OUT2
21
BOOT2
22
V
23
DDP2
V
24
SSD
The TDA8920B is a two channel audio power amplifier using class-D technology.
The audio input signal is converted into a digital Pulse Width Modulated (PWM) signal via
an analog input stage and PWM modulator. To enable the output power transistors to be
driven, this digital PWM signal is applied to a control and handshake block and driver
circuits for both the high side and low side. In this way a level shift is performed from the
low power digital PWM signal (at logic levels) to a high power PWM signal which switches
between the main supply lines.
A 2nd-order low-pass filter converts the PWM signal to an analog audio signal across the
loudspeakers.
The TDA8920B one-chip class-D amplifier contains high power D-MOS switches, drivers,
timing and handshaking between the power switches and some control logic. For
protection a temperature sensor and a maximum current detector are built-in.
The two audio channels of the TDA8920B contain two PWMs, two analog feedback loops
and two differential input stages. It also contains circuits common to both channels such
as the oscillator, all reference sources, the mode functionality and a digital timing
manager.
The TDA8920B contains two independent amplifier channels with high output power, high
efficiency, low distortion and a low quiescent current. The amplifier channels can be
connected in the following configurations:
•
Mono Bridge-Tied Load (BTL) amplifier
•
Stereo Single-Ended (SE) amplifiers.
...continued
Description
5
signal ground for channel 1
6
negative analog supply voltage for channel 1
7
decoupling capacitor for protection (OCP)
8
positive power supply voltage for channel 1
9
bootstrap capacitor for channel 1
10
PWM output from channel 1
11
negative power supply voltage for channel 1
12
decoupling of internal stabilizer for logic supply
-
not connected
13
negative power supply voltage for channel 2
14
PWM output from channel 2
15
bootstrap capacitor for channel 2
16
positive power supply voltage for channel 2
17
negative digital supply voltage
Rev. 01 — 1 October 2004
TDA8920B
2 × 100 W class-D power amplifier
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
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