EL7581_06 INTERSIL [Intersil Corporation], EL7581_06 Datasheet - Page 14

• Manufacturer Part Number: EL7581_06
• Description: 3-Channel DC/DC Converter
• Manufacturer: INTERSIL [Intersil Corporation]

Two-Stage Positive Charge Pump Circuit
The maximum V
R
Where V
Negative Charge Pump Design Considerations
The criteria for the negative charge pump is similar to the
positive charge pump. For a single stage charge pump, the
maximum V
Similar to positive charge pump, if additional stage is
required, the LX switching signal is recommended to drive
the additional charge pump diodes. The figure on the next
page shows a two stage negative charge pump circuit.
V
----------------------------------------------- -
0.5
V
V
ON
11
ON
OFF
×
and R
(
F
max
=
(
max
S
V
1
×
FPB
FBP
)
C
12
)
≤
OUT1
OFF
≥
2
×
set the V
is nominal 1.310V.
I
×
OUT
R
-------------------------- -
V
11
ON
output voltage is:
+
DDP
R
N
×
+
11
output voltage for N+1 stage charge pump is:
2
×
R
- I
×
12
V
ON
(
LX
OUT
R
ONN
output voltage:
(
max
×
14
2
+
) - N
×
R
(
1.265V
ONP
R
R
R
V
V
+
DRNP
-
ONN
×
DDP
ONP
ONN
SSP
FBP


)
2
+
×
+
2 V
+
-
V
R
×
DIODE
ONP
DIODE
) - 2
C
+
CPP
I
OUT
×
- I
V
OUT
DIODE
×
------------------------------------------- -
0.5
×
EL7581
C
------------------------------------------- -
0.5
OUT1
×
- I
V
(5V-17V)
F
BOOST
×
OUT
S
1
F
×
S
C
1
×
×
CPP
C
------------------------------------------- -
0.5
CPN
×
+
V
F
I
OUT
LX
- I
S
1
C
×
OUT
CPP
C
C
×
OUT1
CPP
----------------------------------------------- -
0.5
×
----------------------------------------------- -
0.5
×
- I
F
×
OUT
S
1
F
×
S
C
1
×
×
OUT1
C
R
R
OUT2
12
11


V
ON
- V
DDN