TDA7719 datasheet(26/45 Pages) STMICROELECTRONICS

26 / 45 page

Description

TDA7719

26/45

Figure 19.

DC offset detection circuit (simplified)

4.13

Level meter

In case of not using DC offset detector, the three pins used for this function can be

configured as other functions. Pin27 (DC_Err / LMOUT) then becomes the level meter

output. The level meter block takes signal after main input selector and mix signal into mono,

then rectify the signal and detect the peak of the signal. The output stage of level meter

removes the DC voltage of the signal and the output voltage level shows exactly the Vpeak

of signal. Since the discharge time constant of the level meter is quite slow, it is necessary to

reset level meter regularly (with I2C bus control Byte3 Bit6) to get correct peak information of

the signal.

4.14

Output gain control

The output stage of the device can provide a option to have additional 1dB gain in order to

boost the maximum output level to 2.2Vrms with maximum 1% distortion.

4.15

Audioprocessor testing

In the test mode, which can be activated by setting bit D7 of the I2C subaddress byte and bit

D0 of the testing-audioprocessor byte, several internal signals are available at the QD1L pin.

In this mode, the input resistance of 100kOhm is disconnected from the pin. Internal signals

available for testing are listed in the data-byte specification.

TDA7719 数据表(PDF) 26 Page - STMicroelectronics