tb62736fugel Marktech Optoelectronics, tb62736fugel Datasheet - Page 5

• Manufacturer Part Number: tb62736fugel
• Description: Step-up Type Dc-dc Converter For White Leds
• Manufacturer: Marktech Optoelectronics

Output-side Capacitor Setting
It is recommended that the value of C2 be equal to, or greater than 1.0 (µF).
External Inductor Size Setting
Control of I
Current control using SHDN pin
Dimming using PWM signal input
A dimming function can also by applied using a PWM signal.
[Notes]
<<Output current is calculated using the following equation>>
table below.
This IC can carry out variable of the IF current by external resistance Variable range : 30 to 100%
The resistance RSENS is connected between the FB pin and the GND pin.
The average current is controlled by the RSENS value, and calculated using the following equation:
Margin of error is ±5%.
▪When using a PWM signal, the minimum pulse width of the PWM should be greater than 33µs.
▪Duty ratio of PWM function should be set at 10% - 90%.
▪The recommended PWM frequency should be 100Hz - 10kHz.
Number of LEDs
Io Valuable Rate
SHDN Voltage
For each number of LEDs, the selected inductance should be greater than the value indicated in the
2
3
4
5
6
F
Inductance (Unit: µH)
I
100
F
VSHDN=0V~0.5V
IF(mA) =
80
60
40
20
(mA) = [ 325mV / RSENS(Ω) ]
0
1.0
4.7
6.8
10
0
SHDN input - output rate/output current
1.3
325[mV] × ON Duty [%]
I
F
1.6
VSHDN=1V~2.5V
= 20 mA
VIN=3.0V
VSHDN(V)
Note
RSENS [Ω]
25 - 100
5
1.9
2.2
IF rate
IF
VSHDN>2.5V
2.5
25
20
15
10
5
0
100
TB62736FUG
2004-10-29
UNIT : %
Note