TDA8377A 查看數據表（PDF） - Philips Electronics
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TDA8377A Datasheet PDF : 72 Pages
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Philips Semiconductors
I2C-bus controlled economy PAL/NTSC
and NTSC TV-processors
Preliminary specification
TDA837x family
The input impedance of the black current measuring pin is
14 kΩ. To prevent the voltage on this pin exceeding the
supply voltage during scan an internal protection diode
has been included.
When the TV receiver is switched on the black current
stabilization circuit is not active, the RGB outputs are
blanked and the beam current limiting input pin is
short-circuited. Only during the measuring lines will the
outputs supply a voltage of 4.2 V to the video output stage
to ascertain whether the picture tube is warming up. As
soon as the current supplied to the measuring input
exceeds a value of 190 µA the stabilization circuit will be
activated. After a waiting time of approximately 0.8 s the
blanking and beam current limiting input pins are released.
The remaining switch-on behaviour of the picture is
determined by the external time constant of the beam
current limiting network.
I2C-bus specification
Table 3 Slave address (8A)
A6
A5
A4
A3
A2
A1
A0
R/W
1
0
0
0
1
0
1
I/O
The slave address is identical for all types. The
subaddresses of the various types are slightly different.
The list of subaddresses for each type is given in
Tables 4, 6, 8 and 10.
START-UP PROCEDURE
Read the status bytes until POR = 0 and send all
subaddress bytes. The horizontal output signal is switched
on when the oscillator is calibrated. Each time before the
data in the IC is refreshed, the status bytes must be read.
If POR = 1, then the procedure given above must be
carried out to restart the IC. When this procedure is not
followed the horizontal frequency in the TDA8374 and
TDA8375 may be incorrect after power-up or a power dip.
1997 Jul 01
17
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