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Philips Semiconductors
8. Functional description
8.1 General
TDA8920B_2
Product 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 signal via an
analog input stage and Pulse Width Modulation (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 PWM modulators, 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
Rev. 02 — 07 November 2005
...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
TDA8920B
2 × 100 W class-D power amplifier
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
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