tb62731fug TOSHIBA Semiconductor CORPORATION, tb62731fug Datasheet - Page 11

• Manufacturer Part Number: tb62731fug
• Description: Step-up Dc-dc Converter For White Led Driver
• Manufacturer: TOSHIBA Semiconductor CORPORATION

mounting condition.
fluctuates among ICs.
The self-generated temperature T
Thus, the derating start temperature T
As a result, I
Since saturation thermal resistance θ
Depending on the IC characteristics, peripherals, and use environment, the derating start temperature
T
T
up
s
(°C) = 45 (°C) − 10.4 (°C) = 34.8 (°C)
(°C) = ((0.32 − (0.32 × 0.7)) − (0.5 × 0.1 + 0.3 × 0.02 + 1.8 × 0.02 × 0.02)) × 260 = 10.2 (°C)
120
100
80
60
40
20
o
0
0
is controlled in the recommended current range as shown in Figure 5.
Change from T
Change according to T
Recommended LED current range (converted by 25 mA)
Figure 5 Derating Function of Set Current
s
25
= 34.8°C (20 mA = 100%)
up
( ° C) is calculated as follows:
ja
js
Temperatures T
s
= 260 ( ° C/W) is the maximum value, θ
( ° C) is calculated as follows:
s
50
(°C) and T
11
js
(°C)
75
ja
= 210~260 ( ° C/W) is used as a
100
TB62731FUG
2006-06-14