TDA9109 STMicroelectronics, TDA9109 Datasheet - Page 18

• Manufacturer Part Number: TDA9109
• Description: Multimedia Misc DISC BY STM 11/99
• Manufacturer: STMicroelectronics
• Type: Low Cost Deflection Processorr

Specifications of TDA9109

• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: Through Hole
• Package / Case: SPDIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TDA9109/S
OPERATING DESCRIPTION (continued)
II.2 - PLL1
The PLL1 consists of a phase comparator, an exter-
nal filter and a voltage-controlled oscillator (VCO).
The phase comparator is a "phase frequency" type
designed in CMOS technology. This kind of phase
detector avoids locking on wrong frequencies. It is
followed by a "charge pump", composed of two
current sources : sunk and sourced (typically I = 1mA
when locked and I = 140 A when unlocked). This
difference between lock/unlock allows smooth catch-
ing of the horizontal frequency by PLL1. This effect
is reinforced by an internal original slow down system
when PLL1 is locked, avoiding the horizontal fre-
quency changing too quickly.
The dynamic behaviour of PLL1 is fixed by an exter-
nal filter which integrates the current of the charge
pump. A "CRC" filter is generally used (see Figure 7).
The PLL1 is internally inhibited during extracted
vertical sync (if any) to avoid taking in account
missing pulses or wrong pulses on phase compara-
tor.The inhibition is done by a switch located be-
tween the charge pump and the filter (see Figure 8).
The VCO uses an external RC network. It delivers
a linear sawtooth obtained by the charge and the
discharge of the capacitor, with a current propor-
tional to the current in the resistor. The typical
Figure 8 : Block Diagram
Figure 9 : Details of VCO
18/30
(Loop Filter)
H/HVIN
PLL1F
(1.3V < V
1
7
7
< 6V)
INTERFACE
Tramext
INPUT
6
I
(0.80 < a < 1.30)
2
LOCKDET
C Free Running
COMP1
Adjustment
E2
R0
a
High
Low
I
0
Figure 7
thresholds of the sawtooth are 1.6V and 6.4V.
The control voltage of the VCO is between 1.33V
and 6V (see Figure 9). The theorical frequency
range of this VCO is in the ratio of 1 to 4.5. The
effective frequency range has to be smaller (1 to
4.2) due to clamp intervention on the filter lowest
value. To remove the device and external compo-
nents spread, it is possible to adjust the free run-
ning frequency through I
be done automatically on the manufacturing line
without manual operation by using Hlock/unlock
information. The adjustment range is 0.8 to 1.3 f0
(where 1.3 f0 is the free running frequency at power
on reset).
4 I
I
2
Lock/Unlock
0
CHARGE
0
Status
PUMP
Tramext
5
HPOSITION
INHIBITION
C0
ADJUST
PHASE
6.4V
1.6V
1.8kW
4.7m F
PLL
8
Frequency
6.4V
1.6V
Forced
PLL1F
I
2
C
0 0.875T
7
PLL1F
2
C. This adjustment can
7
HPOS
Adj.
I
2
C
H
FLIP FLOP
T
1 m F
R0
6
H
VCO
RS
OSC
C0
5