HV506
HV Switching Waveforms and Operation
To drive a TFEL row with a negative pulse: The desired sink SCR
is enabled and V
SS
is connected to -HV via a current limited
switch. After holding the output at the -HV level, the switch is
opened in order to set the sink SCR current to zero. The row is
then discharged through a discharge diode when D
2
is switched
to GND. The application of a positive pulse to a row operates in
a similar manner using the selected source SCR and D
1
.
+ HV - (V
DD
- V
SS
)
V
SS
0V
Drive Current
Disabled
- HV
Drive Current
Disabled
High Impedance
Output n
Sink*
SCR
D
2
*
t
OFF
(D
2
)
t
OFF
(Sink SCR)
t
OFF
(Source SCR)
t
OFF
(D
1
)
Output n+1
High Impedance
Source*
SCR
D
1
*
High Impedance
*
Notes internal device handling current flow. Refer to Typical Output Circuit Connections for schematic.
8
SUPERTEX [ Supertex, Inc ]
