DDP3310B Datasheet, PDF (14/60 Pages) Micronas – Display and Deflection Processor

DDP 3310B
ADVANCE INFORMATION
The picture tube measurement returns results on
every field for:
– cutoff R
– cutoff G
– cutoff B
– white-drive R or G or B (sequentially)
Thus, a cutoff control cycle for RGB requires one field
only while a complete white-drive control cycle
requires three fields. During cutoff and white-drive
measurement the average beam current limiter func-
tion (see Section 2.2.5.) is switched off. The amplitude
of the cutoff and white-drive measurement lines can be
programmed separately with IBRM and WDRM (see
Fig. 2–11). The start line for the tube measurement
(cutoff red) can be programmed via I²C-bus (TML).
The built-in control loop for cutoff and white-drive can
operate in three different modes selected by
CUT(WDR)_GAIN and CUT(WDR)_DIS.
– The user control mode is selected by setting
CUT(WDR)_GAIN = 0. In this mode the registers
CUT(WDR)_R/G/B are used as direct control values
for cutoff and drive using the whole 9-bit range. If
the measurement lines are enabled
(CUT(WDR)_DIS = 0) the user can read the mea-
sured cutoff & white drive values in the CUT-
OFF(WDRIVE)_R/G/B registers. An external soft-
ware can now control the settings of the
CUT(WDR)_R/G/B registers.
– The automatic mode is selected by setting
CUT(WDR)_GAIN > 0 and CUT(WDR)_DIS = 0. In
this mode, the registers CUT(WDR)_R/G/B are
used as reference for the measured values (CUT-
OFF(WDRIVE)_R/G/B). Due to the 8-bit resolution
of the ADC, only 8 LSB can be used as reference
values. The calculated error is used with a small
hysteresis (1,5 %) to adjust cutoff and drive. The
higher the loop gain (CUT(WDR)_GAIN), the
smaller the time constant for the adjustment.
– If the automatic mode was once enabled
(CUT(WDR)_GAIN > 0), the control loop can be
stopped by setting CUT(WDR)_DIS = 1. In this
mode, the calculated cutoff and drive values will no
longer be modified and the measurement lines are
suppressed. Changes of the reference values
(CUT(WDR)_R/G/B) have no effect.
If one of the calculated red, green, or blue white-drive
values exceeds its maximal possible value (WDR_R/
G/B>511), the white balance gets misadjusted. An
automatic drive saturation avoidance prevents from
this effect (WDR_SAT = 1) from occurring. If one drive
value exceeds the maximum allowed threshold
(MAX_WDR), the amplitude of the white-drive mea-
surement line will be increased and decreased if one
of them goes below the fixed threshold 475.
ROUT
GOUT
Black
Ultra Black
BOUT
Active
Resistors
R1||R2||R3
Measurement
BCL
OFFSET
Lines
VBSO
Fig. 2–11: MADC measurement timing
14
CUT_R + IBRM + WDRM×WDR_R
CUT_R + IBRM
Cutoff
R
White-
Drive
R
CUT_G + IBRM
Cutoff
G
CUT_B + IBRM
Cutoff
B
R1
TML
CUTOFF
R1||R3
R1
R1||R2||R3
WDR
BCL
VBST
Micronas