NCP1835 ON Semiconductor, NCP1835 Datasheet - Page 11

• Manufacturer Part Number: NCP1835
• Description: Integrated Li-Ion Charger
• Manufacturer: ON Semiconductor

Input and Output Capacitor Selection
recommended for the input bypass capacitor. For the output
capacitor, when there is no battery inserted and the
NCP1835 is used as an LDO with 4.2 V or 4.242 V output
voltage, a 4.7 mF or higher value tantalum capacitor is
recommended for stability. With the battery attached, the
output capacitor can be any type with the value higher than
0.1 mF.
R
Current
ground programs the pre−charge current, full charge
current, and end−of−charge detection threshold. The
nominal voltage of ISEL is 0.8 V. The charge current out
of BAT pin is 100,000 times the current out of ISEL pin.
Therefore, the full charge current (I
with the R
resistance value for desired currents.
Table 2. Charge Current vs. R
ISEL
A 4.7 mF or higher value ceramic capacitor is
A single resistor, R
I
The following table and curves show the selection of the
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
PC
I
FCHG
80
Resistor Selection for Programming Charge
and I
1000
300
500
600
700
800
900
(mA)
Figure 16. Full−Charge Current (I
ISEL
EOC
I FCHG + 100, 000
100
resistor.
Current Select Resistor (R
are 10% of the value programmed above
120
I
PC
ISEL,
/ I
EOC
100
R
30
50
60
70
80
90
ISEL
between the ISEL pin and
140
ISEL
(mA)
(kW)
R ISEL
FCHG
0.8
160
) is:
(A)
R
ISEL
APPLICATION INFORMATION
FCHG
ISEL
133.3
114.3
88.9
267
160
100
80
180
)
(kW)
) vs.
http://onsemi.com
(eq. 1)
200
NCP1835
11
C
prevent the battery from continuously charging which can
cause premature aging or safety issues. The timing
capacitor between TIMER pin and ground, C
end−of−charge time, TIMEOUT, and the pre−charge
timeout. This capacitor is required for proper device
operation.
discharges it to 0.6 V with 6 mA current in one period.
Therefore, the period of the oscillator is:
it reaches the maximum number corresponding to
end−of−charge time, TIMEOUT.
signal if the battery has not completed charging within the
TIMEOUT period. The timeout signal then forces the
FAULT pin low.
TIME
T OSC + 2
0.18
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
The NCP1835 offers an end−of−charge timeout timer to
The internal oscillator charges C
A 22−binary counter counts every oscillator period until
The NCP1835 will terminate charging and give a timeout
TIMEOUT + 2
80
Selection for Programming Charge Time
Figure 17. Pre−Charge Current (I
100
C TIME
Current Select Resistor (R
22
I C
120
T OSC + 14
dV c
R
+ 0.2
ISEL
140
(kW)
TIME
10
C TIME
160
6
1 nF
to 1.2 V and then
C TIME (sec)
ISEL
PCHG
TIME
(minute)
)
180
) vs.
, sets the
(eq. 2)
(eq. 3)
200