AAT2820
Triple-Output Charge Pump Regulator
Design Procedure and
Component Selection
VPOS (V)
# of Stages (n)
7
1
1
1
2
2
2
2
3
3
3
3
3
4
4
4
4
5
5
5
8
Number of Stages for Dual Charge
Pump Regulators
The number of stages required can be determined by:
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
VPOS - 5
NPOS
=
5 - 2VFWD
for the positive output, and
VNEG
2VFWD - 5
NNEG
=
for the negative output.
Where,
Table 1: Number of Stages Required for
Positive Charge Pump.
VNEG = Negative output voltage
VPOS = Positive output voltage
VFWD = Forward voltage drop of the Schottky diode
(0.31V, based on BAT54SDW diode when
IF = 4mA)
VNEG (V)
# of Stages (n)
-7
2
2
3
3
3
3
3
4
4
4
4
5
5
5
5
6
6
6
6
-8
-9
After solving for the number of stages (NPOS and
NNEG), round up the solutions to the next highest
integers for the number of stages required.
-10
-11
-12
-13
-14
-15
-16
-17
-18
-19
-20
-21
-22
-23
-24
-25
Tables 1 and 2 show the number of stages required
for positive and negative charge pumps, respectively.
Table 2: Number of Stages Required for
Negative Charge Pump.
2820.2006.04.1.4
11
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
