ISL97653A Intersil Corporation, ISL97653A Datasheet - Page 15

• Manufacturer Part Number: ISL97653A
• Description: 5-Channel Integrated LCD Supply
• Manufacturer: Intersil Corporation

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In voltage doubler configuration, the maximum V
given by the following equation:
For Voltage Tripler:
V
Negative Charge Pump Design Consideration
The negative charge pump consists of an internal switcher
M1, M2 which drives external steering diodes D2 and D3 via
a pump capacitor (C
supply. An internal comparator (A1) senses the feedback
voltage on FBN and turns on M1 for a period up to half a
CLK period to maintain V
0.2V. External feedback resistor R
Faults on V
are detected by comparator (A2) and cause the fault
detection system to start the internal fault timer which will
cause the chip to power down if the fault persists.
V
V
V
ON
ON_MAX(2x)
ON_MAX(3x)
ON
output voltage is determined by the following equation:
=
V
FBP
OFF
=
=
•
3
⎛
⎜
⎝
2
which cause V
•
1
680KHz
(
•
+
V
(
0.9V
V
R
------ -
R
SUPP
V
12
REF
8
9
SUPP
⎞
⎟
⎠
) to generate the negative V
(FBN)
–
–
V
DIODE
V
15
DIODE
FBN
in regulated operation at
6
)
to rise to more than 0.4V,
–
FB
Error
is referenced to V
)
Control
2 I
–
•
2 I
•
OUT
OUT
( •
FIGURE 16. V
•
3 R
(
ON
•
2 R
OFF
•
ONH
is as
REF
ONH
SUPP
+
ISL97653A
.
+
2 R
(EQ. 15)
(EQ. 16)
(EQ. 17)
M1
ON
•
R
ONL
ONL
FUNCTION DIAGRAM
SUPP
SUPP
)
D3
M3
M5
M2
M4
The maximum V
pump is:
R
V
*Although in the given typical application diagram, SUPP and SUPN are
connected to A
could be connected to either A
V
V
OFF
OFF_MAX
6
OFF
and R
D2
•
(
output voltage.
=
R
ON
V
7
FBN
(
D1
in the Typical Application Diagram determine
2x
(
VDD
NOUT
)
•
, depending on a specific application, SUPN and/or SUPP
=
⎛
⎝
OFF
1
–
+
)H
V
C1-
C1+
POUT
C2+
C2-
FBP
R7
------- -
R6
SUPP
output voltage of a single stage charge
+
⎞
⎠
R
VDD
–
ON
V
+
C21
REF
(
or V
V
NOUT
C22
C7
C8
DIODE
IN.
•
External Connections
⎛
⎝
C14
and Components
R7
------- -
R6
)L
+
⎞
⎠
)
2 I
•
x2 Mode
x3 Mode
Both
R8
R9
OUT
February 21, 2008
(EQ. 19)
(EQ. 18)
FN6367.1