BQ24705 Datasheet, PDF (20/30 Pages) Texas Instruments – Host-Controlled Multi-Chemistry Battery Charger With Low Input Power Detect

bq24705
SLUS779 – DECEMBER 2007
www.ti.com
Table 2. Component List for Typical System Circuit of Figure 2
PART DESIGNATOR
Q1, Q2, Q3
Q4, Q2
D1
R_AC, R_SR
L1
C6, C7, C11, C12
C1, C4, C10
C2, C3, C8, C9, C13, C14, C15
R3, R4
R1
R2
R5
R6
QTY
3
2
1
2
1
5
3
7
4
1
1
1
1
DESCRIPTION
P-channel MOSFET, –30V,-6A, SO-8, Vishay-Siliconix, Si4435
N-channel MOSFET, 30V, 12.5A, SO-8, Fairchild, FDS6680A
Diode, Dual Schottky, 30V, 200mA, SOT23, Fairchild, BAT54C
Sense Resistor, 10 mΩ, 1%, 1W, 2010, Vishay-Dale, WSL2010R0100F
Inductor, 10µH, 7A, 31mΩ, Vishay-Dale, IHLP5050FD-01
Capacitor, Ceramic, 10µF, 35V, 20%, X5R, 1206, Panasonic, ECJ-3YB1E106M
Capacitor, Ceramic, 1µF, 25V, 10%, X7R, 2012, TDK, C2012X7R1E105K
Capacitor, Ceramic, 0.1µF, 50V, 10%, X7R, 0805, Kemet, C0805C104K5RACTU
Resistor, Chip, 10 kΩ, 1/16W, 5%, 0402
Resistor, Chip, 432 kΩ, 1/16W, 1%, 0402
Resistor, Chip, 66.5 kΩ, 1/16W, 1%, 0402
Resistor, Chip, 4 Ω, 1/2W, 1%, 1210
Resistor, Chip, 33 kΩ, 1/16W, 1%, 0402
APPLICATION INFORMATION
Input Capacitance Calculation
During the adapter hot plug-in, the ACDRV has not been enabled. The AC switch is off and the simplified
equivalent circuit of the input is shown in Figure 29.
I_i
R_i
V_i
L_i
C1
C8 C_{i Vc}
A. R_i and L_i are the equivalent input inductance and resistance. C1 and C8 are the input capacitance.
Figure 29. Simplified Equivalent Circuit During Adapter Insertion
The voltage on the input capacitor(s) is given by:
V_C (t) =
V_C (0) +
V_i × w
Z₀
× C_i
×
w
2
0
+
Z₀
V_i
× C_i
× w₀₂
e
-
R_i
2L_i
t
ççèæ
-
R_i
2L _i
sin wt - w × cos wt _{÷÷øö}
(5)
Z₀ =
where:
L_{i w =}
C_{i ,}
1
L_iC_i
-
ççèæ
R_i
2L _i
÷÷øö ²
,
and
w₀
=
1
L_iC_i
20
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