MAX753CSE View Datasheet(PDF) - Maxim Integrated
Part Name
Description
Manufacturer
MAX753CSE Datasheet PDF : 16 Pages
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CCFL Backlight and
LCD Contrast Controllers
Table 3. Spreadsheet Design Equations
PARAMETER
CCFL Specifications
Strike Voltage (VS)
SYMBOL
VS,RMS
Discharging Tube Current (IL)
ILAMP,RMS
Discharging Tube Voltage (VL)
VLAMP,RMS
LCD Contrast Voltage Specifications
Bias Voltage
VLCD
Output Current
ILCD
Royer Specifications
T1 Turns Ratio (Sec/Pri)
n
T1 Resonating Inductance
LMAG
C9 Value
CRES
C10 Value
CBAL
Royer Frequency
w
MAX754 Specifications
Reference Voltage
VREF
Second Volts Constant
sV
CCFL Circuit Calculations
R8 Current-Sensing Resistor
R8
Secondary Voltage Phase vs. Tube
Voltage
phi
T1 Center-Tap Peak Voltage
Secondary Limit Voltage
T1 Center-Tap Limit Peak Voltage
R5/R6
LCD Circuit Calculations
VIN(min) Full-Load Switching Period
VTAP,PK
VLIM
ROTP,RATIO
TFL
L2 Inductance
L2
L2 Peak Currrent
R4/R3
RLCD,RATIO
Application Circuit Operating Range
Input Voltage
VIN
MIN
1100
= 0.28 *
ILAMP,RMS(max)
TYP
435
MAX
1500
0.005
= VLCD(max) / 2
0.0245
0.000008
171
0.000045
2.2E-07
1.5E-11
= SQRT [1 / (LMAG * CRES)]
1.25
32.6
2.4E-05
= PI() * VREF * SQRT(2) /
(2 * ILAMP,RMS(max))
= ATAN (-ILAMP,RMS(max) /
(CBAL * w * + VLAMP,RMS)
= -SQRT(2) * ILAMP,RMS(max) /
(CBAL * w * SIN(phi)) / n
= VS,RMS(max) * 0.9
= SQRT(2) * VLIM / n
= VREF / (D25 - 0.6 - VREF)
= L2(max) * 0.8
= sV(min) / VIN(min) + sV(min) /
(VLCD(max) - VIN(min))
= sV(min) ^ 2 / (2 * TFL *
VLCD(max) * ILCD(min))
= VREF / (VLCD(max) - VREF)
= sV(max) / L2(min)
= (2 / PI()) * VTAP,PK
18
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