TDA7719 STMicroelectronics, TDA7719 Datasheet - Page 25

• Manufacturer Part Number: TDA7719
• Description: IC AUDIO PROCESSOR CAR 28-TSSOP
• Manufacturer: STMicroelectronics
• Type: Audio Processorr
• Series: -r

Specifications of TDA7719

• Applications: Radio
• Mounting Type: Surface Mount
• Package / Case: 28-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TDA7719
4.11
4.12
DC offset detector and level meter option
This device provide DC offset detector function and level meter function option. In one
specific application, only one of the function can be used. The configuration of the function
is controlled by I
When the device uses DC offset detector function, Pin22, Pin27 and Pin28 are used as
WinTC, DCErr and WinIN for DC offset detector. When it is configured as level meter, DCErr
becomes level meter output. In the mean time, WinIN is used as beep input (Mono single-
ended input for mixing), and WinTC becomes a reference voltage output (4 V external DC
voltage or 3.3 V internal reference voltage).
DC offset detector
Using the DC offset detection circuit
audio power amplifier and the TDA7719's Front and Rear outputs can be detected,
preventing serious damage to the loudspeakers. The circuit compares whether the signal
crosses the zero level inside the audio power at the same time as in the speaker cell. The
output of the zero-window-comparator of the power amplifier must be connected with the
WinIn-input of the TDA7719. The WinIn-input has an internal pull-up resistor connected to
5.5Volts. It is recommended to drive this pin with open-collector outputs only.
To compensate for errors at low frequencies the WinTC-pin are implemented, with external
capacitors introducing the same delay τ = 7.5kΩ * C
TDA7719 and the power amplifier introduces. For the zero window comparators, the time
constant for spike rejection as well as the threshold are programmable.
For electrical characteristics see
A low-active DC-offset error signal appears at the DCErr output if the next conditions are
both true:
After power-on, the external attached capacitor is rapidly charged (fast-charge) to overcome
a false indication.
a)
b)
Front and rear outputs are inside zero crossing windows.
The Input voltage VWinIn is logic low whenever at least one output of the power
amplifier is outside the zero crossing windows.
2
C bus (Byte3 Bit7).
Doc ID 13698 Rev 4
Chapter 3 on page
(Figure
19) an offset voltage difference between the
ext
9.
as the AC-coupling between the
Description
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