Controller - Power Supply Circuits - Xilinx Virtex-4 ML461 User Manual

Appendix B: LCD Interface
Controller – Power Supply Circuits
Figure B-5
boost mode, where VDD is 3.3V and VOUT is 16.5V. VOUT is the operating voltage of the
operational amplifier delivering the operating voltage, V0, for the LCD panel.
The LCD operating voltage, V0, is set with two resistors R
when the resistors are external. INTRS is driven High when the resistors are internal. For
the Virtex-4 ML461 Development Board, internal resistors are selected.
The LCD operating voltage (V0) and the Electronic Volume Voltage (V
in units of V with these formulae:
Equation 1:
V0
Equation 2:
V
In Equation 2, V
The values of the reference voltage parameter, α, and the ratio R
bit settings in the LCD controller's instruction registers. Thus, it is possible to change
92
shows the power supply circuits. The power supply is used in the five times
2
VDD
1
VSS
Figure B-5: Power Supply Circuits
R
⎛ ⎞
B
×
1 ----- - V
= +
⎝ ⎠
EV
R
A
63 α
⎛ ⎞
–
×
1 -------------- - V
= –
⎝ ⎠
EV
300
is equal to 2.0V at 25 °C.
REF
www.xilinx.com
DUTY1
DUTY2
BSTS
VR
MS
INTRS
17 VDD
18 VOUT
25
26
27
28
29
30 VSS1
16 VSS
DCDC5B
REF
Virtex-4 ML461 Development Board User Guide
VOUT
5 x VDD
VDD
VSS
ug077_b_05_081005
and R . INTRS is driven Low
A B
) can be calculated
EV
/R are determined with
A B
UG079 (v1.1) September 5, 2007
R