AOZ9004B
Applications Information
EB+
R1
220Ω
8
7
6
5
IC
VDD
VM
IC
Single-Cell
Lithium-Ion/
Lithium Polymer
Battery
R2
2kΩ
C1
0.1μF
AOZ9004B
VSS
1
IC
2
IC
3
OUTM
4
EB-
Figure 6. AOZ9004B Applications Circuit
A low-pass filter formed by R1 and C1 reduces supply
voltage fluctuation on the VDD pin. R1 also provides ESD
protection and serves as an current-limiting resistor in the
event of charger reverse connection. The supply current
of AOZ9004B has to flow through R1, so a small R1
should be chosen to guarantee detection accuracy of
VDD voltage. Choose a resistor value between 100ꢀ and
330ꢀ for R1. Choose the value of C1 to be 0.022µF or
higher. Both R1 and C1 should be placed as close as
possible to AOZ9004B to minimize parasitic effect.
R2 provides ESD protection and serve as a current-
limiting resistor in the event of charger reverse connec-
tion. A large value resistor should be chosen to limit
power consumption during this condition. However, an
extremely large value of R2, of course, will cause
inaccuracy of VM pin voltage detection. Choose a
resistor value between 300ꢀ and 4kꢀ for R2.
Table 3. External Components Selection Range
Designator
Purpose
Min.
Typ.
Max.
R1
Reduce supply voltage fluctuation, provide ESD protection, and limit current
when a charger is reversely connected
0.022µF
0.1µF
1.0µF
C1
R2
Reduce supply voltage fluctuation
100ꢀ
300ꢀ
220ꢀ
2kꢀ
330ꢀ
4kꢀ
Provide ESD protection and limit current when a charger is reversely
connected
Rev. 1.2 August 2008
www.aosmd.com
Page 14 of 17
AOS [ ALPHA & OMEGA SEMICONDUCTORS ]
