tb62734fmg TOSHIBA Semiconductor CORPORATION, tb62734fmg Datasheet - Page 5

• Manufacturer Part Number: tb62734fmg
• Description: Step-up Type Dc-dc Converter For White Led?s
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Setting the Output Side Capacitance
A C2 of 0.47 (µF) or greater is recommended.
Setting the External Inductor Size
Reference: According to the number of LED’s, select an inductor size greater than the corresponding value
Setting of I
Connect the RSENS resistor between the RSENS pin and GND. The RSENS resistor (K terminal and Ground) is
used for setting the output current (I
corresponding to the number of LED’s.)
The equations above apply only to the inductor sizes we recommend, i.e., they cannot be used to calculate average
current if the inductor sizes used differ from those recommended.
Average currents set by this RSENS value are obtained using the following equations. (Choose the equation
Number of LED’s
2 LED’s: I
3 LED’s: I
4 LED’s: I
5 LED’s: I
6 LED’s: I
indicated in the table below.
50
45
40
35
30
25
20
15
10
2
3
4
5
6
O
0
O
O
O
O
O
= 119.16 × RSENS
= 115.32 × RSENS
= 113.08 × RSENS
= 108.02 × RSENS
= 106.71 × RSENS
V
IN
= 2.8V to 5.5V
2
4.7
6.8
10
O
).
− 0.8399
− 0.854
− 0.8614
− 0.8534
− 0.836
4
RSENS vs Iout
RSENS vs I
I
Vin=3.6V
O
V
Unit: µH
IN
= 20 mA
Note
RSENS(Ω)
RSENS (Ω)
= 3.6 V
5
6
OUT
8
10
2 LEDs
3 LEDs
4 LEDs
5 LEDs
6 LEDs
2LED
3LED
4LED
5LED
6LED
TB62734FMG
12
2006-06-14