BQ24700_14 Datasheet, PDF (12/32 Pages) Texas Instruments – NOTEBOOK PC BATTERY CHARGE CONTROLLER

bq24700, bq24701
ą
NOTEBOOK PC BATTERY CHARGE CONTROLLER
AND SELECTOR WITH DPM
SLUS452B – APRIL 2001 – REVISED NOVEMBER 2002
pin assignments (continued)
VHSP: The VHSP pin is connected to a 10-µF capacitor (close to the pin) to provide a stable voltage source
to drive the gates of the external MOSFETs. VHSP is equal to (0.5 × VCC) for VCC ≥ 15 V and 0 V for VCC < 15
V (refer to Figure 12). An 18-V Zener diode should be placed between VCC and VHSP for VCC > 20 V to prevent
MOSFET overstress during start-up.
VREF: Bypassed precision voltage 5-V, ±0.6% output. It can be used to set fixed levels on the inverting inputs
of any one of the three error amplifiers if desired. The tight tolerance is suitable for charging lithium-ion batteries.
A 3.3-µF (or higher) capacitor should be placed close to the pin.
VS: System (Load) voltage input pin. The voltage on this pin indicates the system voltage in order to insure a
break before make transition when changing from ac power to battery power. The battery is protected from an
over-voltage condition by disabling the P-channel MOSFET connected to the BATDRV pin if the voltage at VS
is greater than BATP. This function can be eliminated by grounding the VS pin.
APPLICATION INFORMATION
D1
R5
ADAPTER MBRD640CT _0.025
SUPPLY
DPAK
1W
100 kΩ
100 Ω
1 µF
R1
499 kΩ
Q2
IRFR5305
33 µH
D05022p–333
100 Ω
bq24700PW
11 ACN
ACDRV 24
Q1
IRFR5305
220 µF
30 V
D1
MBRD640CT
R6
0.05
0.5 W
DPAK
12 ACP
VCC 22
4.7 Ω
VBAT
R7
523 kΩ
1 ACDET
PWM 21
8 ENABLE
SRP 16
3 ACSEL
SRN 15
19 ALARM
BATP 13
5 SRSET BATDRV 23
6 ACSET
VS 18
2 ACPRES VHSP 20
4.7 µF
C3 10µ F
B330
B330
R10
20 Ω
10Ω
12.6 V +
R9
57.6 kΩ
100 kΩ
J1
D3
18 V
Q3
IRFR5305
C5, C6
22 µF
x2
35 V
20 kΩ
5VREF
C7
3.3 µF
C8 150 pF
C9 R13
4.7 µF 100 Ω
14 IBAT
7 VREF
10 _COMP
BATSET 9
BATDEP 4
GND 17
C4
10 µF
35 V
499 kΩ
180 pF 76.8 kΩ
CHARGE VOLTAGE SETPOINT
Figure 1. Typical Notebook Charge Management Application
D4
17 V
TO SYSTEM
D4
17 V
R14
523 kΩ
R15
57.6 kΩ
VCC
VBAT
UDG–00138
12
• POST OFFICE BOX 655303 DALLAS, TEXAS 75265