TDA4853 Datasheet, PDF (14/60 Pages) NXP Semiconductors – I2C-bus autosync deflection controllers for PC/TV monitors

Philips Semiconductors
I²C-bus autosync deflection controllers for
PC/TV monitors
Product specification
TDA4853; TDA4854
For supply voltages below 8.3 V the internal I²C-bus will
not generate an acknowledge and the IC is in standby
mode. This is because the internal protection circuit has
generated a reset signal for the soft start
register SOFTST. Above 8.3 V data is accepted and all
registers can be loaded. If the register SOFTST has
received a set from the I²C-bus, the internal soft start
procedure is released, which activates all mentioned
outputs.
If during normal operation the supply voltage has dropped
below 8.1 V, the protection mode is activated and
HUNLOCK (pin 17) changes to the protection status and is
floating. This can be detected by the microcontroller.
This protection mode has been implemented in order to
protect the deflection stages and the picture tube during
start-up, shut-down and fault conditions. This protection
mode can be activated as shown in Table 3.
When the protection mode is active, several pins of the
TDA4853; TDA4854 are forced into a defined state:
HDRV (horizontal driver output) is floating
BDRV (B+ control driver output) is floating
HUNLOCK (indicates, that the frequency-to-voltage
converter is out of lock) is floating (HIGH via external
pull-up resistor)
CLBL provides a continuous blanking signal
VOUT1 and VOUT2 (vertical outputs) are floating
The capacitor at HPLL2 is discharged.
If the soft start procedure is activated via the I²C-bus, all of
these actions will be performed in a well defined sequence
(see Figs 25 and 26).
Table 3 Activation of protection mode
ACTIVATION
Low supply voltage at
pin 10
Power dip, below 8.1 V
X-ray protection (pin 2)
triggered, XSEL (pin 9) is
open-circuit or connected
to ground
X-ray protection (pin 2)
triggered, XSEL (pin 9)
connected to V_CC via an
external resistor
HPLL2 (pin 30) externally
pulled to ground
RESET
increase supply voltage;
reload registers;
soft start via I²C-bus
reload registers;
soft start via I²C-bus
reload registers;
soft start via I²C-bus
switch V_CC off and on
again, reload registers;
soft start via I²C-bus
release pin 30
1999 Jul 13
14