tb62732fug TOSHIBA Semiconductor CORPORATION, tb62732fug Datasheet - Page 10

• Manufacturer Part Number: tb62732fug
• Description: Step-up Dc/dc Converter For White Led Driver
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Application Evaluation Circuit Example 1
(Example of evaluation result using a small coil: Coil LDR304612T-6R8)
6.8 µH is optimum for illuminating serial LEDs 3 to 4 LEDs using I
4.7 µH is recommended for steady illumination of serial LED 2 in the range V
Note 5: Connection of C
25
20
15
25
20
15
3
3
The I
3.2
3.2
F
3.4
3.4
is expected to stabilize on decrease of voltage.
V
V
IN
IN
– Efficiency/I
– Efficiency/I
3.6
3.6
V
V
IN
IN
3
is not necessary in every case.
(V)
(V)
3.8
3.8
3.0 to 4.3 V
V
IN
F
F
4 LEDs efficiency
4 LEDs I F
2 LEDs efficiency
2 LEDs I F
4
4
=
L1 : TDK LDR304612T-6R8
S-Di : TOSHIBA CUS02 30 V/1 A
LED : NICHIA NSCW215T
4.2
4.2
ON
OFF
85
80
75
70
65
85
80
75
70
65
V
SHDN
L1 = 6.8 µH S-Di
CC
10
GND
<Measurement>
Efficiency in the range V
I
Note 6: The above values have been obtained
Number
F
Number
A
of LED
of LED
K
in the range V
25
20
15
2
3
4
2
3
4
3
F
through Toshiba’s own measurements.
However, results may vary according to the
measurement environment.
= 20 mA.
3.2
Efficiency (%)
I
79.0 to 83.8
75.1 to 80.9
72.0 to 78.3
19.5 to 21.1
19.5 to 20.5
19.6 to 20.7
F
3.4
I
V
IN
F
IN
3 to 4
LEDs
IN
(mA)
= 3.0 to 4.3 V
– Efficiency/I
> 4.5 V.
3.6
V
IN
IN
(V)
3.8
= 3.0 to 4.3 V
V
F
3 LEDs efficiency
3 LEDs I F
Average Efficiency
CC
4
TB62732FUG
Dependence (%)
4.2
81.6
78.3
75.7
(%)
7.8
4.9
5.3
2006-06-14
85
80
75
70
65