TDA8922B
Philips Semiconductors
2 × 50 W class-D power amplifier
Table 3:
Symbol
Pin description …continued
Pin
Description
TDA8922BTH TDA8922BJ
SGND1
VSSA1
PROT
VDDP1
BOOT1
OUT1
VSSP1
STABI
n.c.
11
12
13
14
15
16
17
18
19
20
21
22
23
24
5
signal ground for channel 1
6
negative analog supply voltage for channel 1
decoupling capacitor for protection (OCP)
positive power supply voltage for channel 1
bootstrap capacitor for channel 1
PWM output from channel 1
7
8
9
10
11
12
-
negative power supply voltage for channel 1
decoupling of internal stabilizer for logic supply
not connected
VSSP2
OUT2
BOOT2
VDDP2
VSSD
13
14
15
16
17
negative power supply voltage for channel 2
PWM output from channel 2
bootstrap capacitor for channel 2
positive power supply voltage for channel 2
negative digital supply voltage
8. Functional description
8.1 General
The TDA8922B 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 TDA8922B 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 TDA8922B 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 TDA8922B 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.
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
9397 750 13357
Preliminary data sheet
Rev. 01 — 1 October 2004
5 of 32
NXP [ NXP ]
