Rainbow Electronics MAX781 - Manual (Page 7)

MAX781
PDA/Hand-Held Computer Power Controller
_______________________________________________________________________________________ 7
10
1 10 100 1000
3OUT OPERATE MODE POWER EFFICIENCY
VARIABLE SWITCHING FREQUENCY
MAX781-09
3OUT OUTPUT CURRENT (mA)
POWER EFFICIENCY (%)
20
30
40
50
60
70
80
90
100
BATT = 7.5V
SYNC = AGND
IDLE = 1
MODE1 = 1
MODE0 = 0
0
50
100
150
200
250
300
350
400
450
SWITCHING EFFICIENCY (kHz)
% kHz
0
0
USING THE BATTERY CHARGER TO DRIVE
A CCFL BACKLIGHT ROYER OSCILLATOR
MAX781-01
CHG6–CHG0 BITS VALUE
CCFL TUBE CURRENT (mA, rms) CSBAT AVERAGE VOLTAGE (mV)
10
20
mV
30
40
50
60
70
80
90
100
110
10 20 30 40 50 60 70
0.5
1.0
1.5
2.0
2.5
SYNC = REF
VCHG = 7V
BATT = VCHG - DIODE DROP
R4 = 0.47
Ω
mA, rms
____________________________Typical Operating Characteristics (continued)
(T A = +25°C, unless otherwise noted.)
______________________________________________________________Pin Description
21 DLO +3.3V Regulator, Synchronous Rectifier, Gate-Driver Output
22 BST +3.3V Regulator Boost Capacitor Connection (0.1µF to LX)
23 DHI +3.3V Regulator High-Side Gate-Driver Output
24 LX +3.3V Regulator Inductor Connection
20 PGND Power Ground
12 DOUT Serial-Interface Data Output
13 DIN Serial-Interface Data Input
16 COMP Battery-Charger Compensation
NAME FUNCTION
1–4 GD2–GD5 High-Side Gate-Driver Outputs
5 VPPA VPP-Programming Voltage Output A
PIN
17 CSBAT Battery-Charger Current-Sense Input
18 5OUT Linear-Regulated +5V Output
19 DCHG Battery-Charger MOSFET Gate-Driver Output
14 INT Interrupt Output
15 FAST General-purpose open-drain output
8 AGND Analog Ground
9 SYNC Oscillator Frequency Control and Synchronization Input
10 CE Serial-Interface Chip-Enable Input—active high
11 SCLK Serial-Interface Clock Input
6 VHI VPPA, VPPB Linear-Regulator Input Power
7 VPPB VPP-Programming Voltage Output B