TDA8929 Ver la hoja de datos (PDF) - Philips Electronics

Número de pieza

componentes Descripción

Fabricante

TDA8929

Controller class-D audio amplifier

Philips Electronics 

Philips Semiconductors

Controller class-D audio amplifier

Preliminary specification

TDA8929T

15 TEST AND APPLICATION INFORMATION

15.1 Test circuit

The test diagram in Fig.10 can be used for stand alone

testing of the controller. Audio and mode input pins are

configured as in the application. For the simulation of a

switching output power stage a simple level shifter can be

used. It converts the digital PWM signal from the controller

(switching between VSS and VSS + 12 V level) to a

PWM signal switching between VDD and VSS.

A proposal for a simple level shifting circuit is given

in Fig.9.

The low-pass filter performs the demodulation, so that the

audio signal can be measured with an audio analyzer. For

measuring low distortion values, the speed of the level

shifter is important. Special care has to be taken at a

sufficient supply decoupling and output waveforms without

ringing.

The handshake with the power stage is simulated by a

direct connection of the release inputs (REL1 and REL2)

with the switch outputs (SW1 and SW2) of the controller.

The enable outputs (EN1 and EN2) for waking-up the

power stage are not used here, only the output level and

timing are measured.

handbook, full pagewidth

switch

0/12 V

VSS

2 kΩ

+5 V

20 kΩ

10 kΩ

BST82

1.33 kΩ

74LV14

10 Ω

PHC2300

10 nF

10 Ω

33 Ω

42 Ω

VDD

PWM

MGW154

VSS

Fig.9 Level shifter.

2001 Dec 11

17

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