EL5000AER INTERSIL [Intersil Corporation], EL5000AER Datasheet - Page 7

• Manufacturer Part Number: EL5000AER
• Description: High Voltage TFT-LCD Logic Driver
• Manufacturer: INTERSIL [Intersil Corporation]

Application Information
General Description
The EL5000A is a high performance 70V TFT-LCD row
driver. It level shifts TTL level timing signals from the video
source into 70V peak to peak output voltage. Its output is
capable of delivering 100mA peak current into 1nF of
capacitive load. It also incorporates logic to control the
output timings. The logic timing control circuit is powered
from 3.3V supply. Figure 15 shows the system block
diagram.
Input Signals
The device performs beside of level transformation also logic
operation between the input signals:
• STV - Vertical Sync Timing signal, frequency range around
• CPV - Horizontal Sync Timing signal, frequency range up
• OE - Output Enable Write Signal, frequency range up to
Output Signals
The output signals, CKV and CKVB are generated by
EL5000A internal switches. Figure 16 depicts the simplified
schematic of the output stage and interface.
60Hz
to 166kHz
166kHz
FIGURE 16. SIMPLIFIED SCHEMATIC OF OUTPUT STAGE
7
FIGURE 15. EL5000A SYSTEM BLOCK DIAGRAM
EL5000A
EL5000A
C
inputs of the TFT-LCD panel for the CKV and the CKVB
signals. The C
In addition to switches SW1, SW2, SW3, and SW4, a fifth
switch is added to reduce the power dissipation and shape
the output waveform. Figure 17 shows the location of the
additional SW5 switch.
In reality, each switch consists of two such switches, one for
the positive discharge and one for the negative discharge,
see Figure 18.
Due to the actual solid-state construction of the switches, the
capacitors C
of left over charges depends on the value of the voltages of
V
ON
L
capacitors model the capacitive loading appeared at the
and V
CL
r
CKV
FIGURE 18. BI-DIRECTIONAL SWITCHES
OFF
FIGURE 17. SW5 SWITCH LOCATION
L
does not get discharged entirely. The amount
L
on the capacitors.
is typically between 1nF and 5nF.
SW1
SW3
SW5
Rd
SW2
SW4
CKVB
r
July 28, 2005
FN6167.0
CL