KB2511B View Datasheet(PDF) - Samsung
Part Name
Description
MFG CO.
'KB2511B' PDF : 35 Pages View PDF
KB2511B
DEFLECTION PROCESSOR FOR MULTISYNC MONITORS
I2C Free running
Adjustment
ID
2
Loop
Filter 7 +
-
a ID
4 I0
(0.80<a<1.30) 2
(1.3V < V7 < 6V) 6
R0
+
6.4V -
+
1.6V -
RS
FLIP
FLOP
5
6.4V
Co 1.6V
0 0.84T T
Figure 10. Details of VCO
The control voltage of the VCO is typically comprised between 1.33V and 6V (see figure 10). The theorical
frequency range of this VCO is in the ratio 1 to 4.5, the effective frequency range has to be smaller 1 to 4.2 due to
clamp intervention on filter lowest value. To avoid spread of external components and the circuit itself, it is possible
to adjust free running frequency through I2C. This adjustment can be made automatically on the manufacturing line
without manual operation by using hlock/unlodk information. The adjustment range is 0.8 to 1.3 F0 (where 1.3 F0 is
the free running frequency at power on reset).
The sync frequency has to be always higher than the free running frequency. As an example for a synchro range
from 24kHz to 100kHz, the suggested free running frequency is 23kHz.
An other feature is the capability for MCU to force horizontal frequency throw I2C to 2xF0 or 3xF0 (for burn in mode
or safety requirement). In this case, inhibition switch is opened leaving PLL1 free but voltage on PLL1 filter is
forced to 2.66V for 2xF0 or 4.0V for 3xF0.
The PLL1 ensures the coincidence between the leading edge of the synchro signal and a phase reference
obtained by comparism between the sawtooth of the VCO and an internal DC voltage I2C adjustable between
2.65V and 3.75V (corresponding to ±10%) (see figure 11)
H Osc
Sawtooth 7/8TH
1/8TH
Phase REF1
H Synchro
6.4V
2.65V < Vb < 3.75V
Vb
1.6V
Phase REF1 is obtained by compari-
sion between the sawtooth and a DC
voltage adjustable between 2.6V and
3.8V. The PLL1 ensures the exact
coindidence between the signals
phase REF and HSYNS. A ±TH/10
phase adjustment is possible
Figure 11. PLL1 Timing Diagram
26
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