BQ24704 Datasheet, PDF (21/31 Pages) Texas Instruments – Low Cost, Host-Controlled Li-Ion and Li-Polymer Battery Charger With Low Iq

bq24704
www.ti.com........................................................................................................................................................................................................ SLUS838 – MAY 2009
Table 2. Component List for Typical System Circuit of Figure 1
PART DESIGNATOR
Q1, Q2, Q3
Q4, Q5
D1, D2
R_AC, R_SR
L1
C6, C7, C11, C12
C4, C10
C2, C3, C8, C9, C13, C14, C15
C5
C1
R3, R4, R15
R1
R2
R10
R6
QTY
3
2
2
2
1
4
2
7
1
1
3
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, 8.2µH, Vishay-Dale, IHLP5050CE-01
Capacitor, Ceramic, 10µF, 25V, 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
Capacitor, Ceramic, 100pF, 25V, 10%, X7R, 0805, Kemet, C0805C101K5RACTU
Capacitor, Ceramic, 2.2µF, 25V, 10%, X7R, 2012, TDK, C2012X7R1E225K
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, 2 Ω, 1W, 1%, 1210
Resistor, Chip, 20 kΩ, 1/16W, 1%, 0402
APPLICATION INFORMATION
Input Capacitance Calculation
During the adapter hot plug-in, the ACFET has not been turned on. The AC switch is off and the simplified
equivalent circuit of the input is shown in Figure 29.
I_IN
V_IN
Charger
R_i
V_i
L_i
R_c
C_i
A. R_i: Equivalent resistance of cable
B. L_i: Equivalent inductance of cable
C. R_C ESR of C_i
D. C_i: Decoupling capacitor
Figure 29. Simplified Equivalent Circuit During Adapter Insertion
The voltage on the input capacitor(s) is given by:
V_IN(t) =
I_IN (t)
x
R_C
+
V_Ci (t)
=
V_i
-
R_{t t}
V_Ie ^2Li
êëéê
R_i - R_C
wL_i
sinwt + coswt^{ùúúû}
V_Ci(t) =
V_i
-
R_{t t}
V_Ie ^2Li
éê _Rt
êë _2wLi
sinwt + coswt^{ùúúû}
R_t = R_i + R_C
w=
I
L_iC_i
-çççèæç
R_t
2L_i
÷÷ø÷÷ö²
I_In(t) =
V_i
wL_i
R_{t t}
e ^2Li
sinwt
(6)
Copyright © 2009, Texas Instruments Incorporated
Product Folder Link(s) :bq24704
Submit Documentation Feedback
21