el7641 Intersil Corporation, el7641 Datasheet - Page 16

• Manufacturer Part Number: el7641
• Description: Tft-lcd Dc/dc With Integrated Amplifiers
• Manufacturer: Intersil Corporation

Component Selection for Start-up Sequencing and
Fault Protection
The C
to stabilize the V
22nF to 1µF and should not be more than five times the
capacitor on C
The C
range from 47nF minimum to several microfarads – only
limited by the leakage in the capacitor reaching µA levels.
REF
DEL
capacitor is typically 220nF and has a usable
capacitor is typically set at 220nF and is required
DEL
REF
V
to ensure correct start-up operation.
ON SLICE
output. The range of C
CIRCUIT
V
16
BOOST
V
V
V
CDLY
V
REF
OFF
ON
IN
REF
EL7640, EL7641, EL7642
FIGURE 23. START-UP SEQUENCE
is from
START-UP SEQUENCE
t
ON
TIMED BY C
t
DEL1
DLY
C
above). Note with 220nF on C
typically 50ms and the use of a larger/smaller value will vary
this time proportionally (e.g. 1µF will give a fault time-out
period of typically 230ms).
Fault Sequencing
The EL7640, EL7641 and EL7642 have an advanced fault
detection system which protects the IC from both adjacent
pin shorts during operation and shorts on the output
DEL
t
DEL3
t
DEL2
should be at least 1/5 of the value of C
OPERATION
NORMAL
DEL
PRESENT
FAULT
the fault time-out will be
REF
February 22, 2006
(see
FN7415.2