el7583 Intersil Corporation, el7583 Datasheet - Page 11

• Manufacturer Part Number: el7583
• Description: 3-channel Dc/dc Converter
• Manufacturer: Intersil Corporation

Single Stage Charge Pump
Positive Charge Pump Design Considerations
A single stage charge pump is shown above. The maximum
V
where:
• R
If additional stage is required, the LX switching signal is
recommended to drive the additional charge pump diodes.
The drive impedance at the LX switching is typically 220mΩ.
The figure below illustrates an implementation for two-stage
positive charge pump circuit.
V
ON
ON
voltage levels. For 12V supply, R
6V supply, R
V
ONN
OFF
(
output voltage is determined by the following equation:
max
5V TO
and R
17V
)
≤
2
×
R
ON
ONP
21
V
R
C
3.3µF
DDCPP
22
OUT2
is typically 45Ω.
resistance values depend on the V
0.1µF
C
V
- I
CPN
REF
OUT
11
×
V
DRVN
V
FBN
DDN
2
SSN
R
R
×
ON
ONP
ONN
(
R
ONN
is typically 33Ω. For
+
R
+
-
ONP
R
ON
) - 2
IS 30 - 40Ω FOR V
DDP
×
V
DIODE
EL7583
OSC
- I
OUT
DD
6V TO 12V
×
------------------------------------------- -
0.5
×
F
S
1
×
C
+
-
CPP
+
-
- I
V
R
R
FBP
OUT
ONP
ONN
DRVP
V
V
FBP
DDP
SSP
×
----------------------------------------------- -
0.5
×
F
S
1
×
C
0.1µF
OUT1
C
CPP
R
R
12
11
C
2.2µF
May 12, 2006
OUT1
FN7335.5
5V TO
17V
V
ON