EV1529DR-00A Datasheet, PDF (4/4 Pages) Monolithic Power Systems – Fixed Frequency Step-Up Converter LCD Backlight Plus Flash Evaluation Board

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EV1529DR-00A – FIXED FREQUENCY CONVERTER LCD BACKLIGHT EV BOARD
QUICK START GUIDE
The LED currents at backlight mode, backlight plus review mode and flash mode are set to 20mA, 40mA, and
100mA, respectively on this board. The board layout accommodates mostly common used inductors and
output capacitors.
1. Preset Power Supply to 2.7V ≤ V_IN ≤ 4.2V.
2. Turn Power Supply off.
3. Connect Power Supply terminals to:
a. Positive (+): VIN
b. Negative (–): GND
4. Solder the first backlight LED string to LED1 - LED4.
Solder the second backlight LED string to LED5 – LED8.
Solder the flash LED string to LED9 – LED12.
Set EN1 and EN2 based on the Enable Operation Table below. Connect EN1, EN2 to VIN to set
them “H” and to GND to set them “L”.
Mode
Off
Backlight
Backlight plus Preview
Flash
EN1
L
H (PWM)
H (PWM)
L
EN2
Strings 1+2: LCD
Backlight LEDs
L Off
L On (PWM)
H On (PWM)
H Off
String 3: Flash
LEDs
Off
Off
Preview current
Flash current
5. Turn Power Supply on after making connections.
The LED currents can be adjusted by changing the values of resistors RS1, RS2, and RS3. VSET = 1.216V.
RS1 = ^{950 × VSET}
I_{LED _ BL}
RS2 = ^{1100 × VSET}
I_{LED _ PV}
RS3 = ^{1000 × VSET}
I_{LED _ FL}
For examples, If I_{LED_BL} = 10mA, then
RS1 = ^{950 × 1.216} = 115.52kΩ (Use a 115kΩ 1% resistor)
10
If I_{LED_PL} = 20mA, then
RS2 = ^{1100 × 1.216} = 66.88kΩ (Use a 66.5kΩ 1% resistor)
20
If I_{LED_FL} = 150mA, then
RS3 = ^{1000 × 1.216} = 8.11kΩ (Use a 8.06kΩ 1% resistor)
150
NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications.
Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS
products into any application. MPS will not assume any legal responsibility for any said applications.
EV1529DR-00A Rev. 1.0
www.MonolithicPower.com
4
11/2/2005
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