STLDC08 STMicroelectronics, STLDC08 Datasheet - Page 19

• Manufacturer Part Number: STLDC08
• Description: Step-up controller for LED supply
• Manufacturer: STMicroelectronics

STLDC08
8.5
Equation 11
Equation 12
Equation 13
If the R
following procedure must be performed to choose the Power MOSFET. During ON time, the
SENSE comparator limits the voltage across the Power MOSFET to a nominal 100 mV. In
that case, the maximum inductor current is given by the following relationships:
Equation 14
Equation 15
Equation 16
Power MOSFET selection
A key parameter to take into account in the selection of the N-MOSFET is the maximum
continuous drain current. As a safety design, it is important to choose a maximum
continuous drain current equal to twice the maximum input current.
DS (ON)
of the main Power MOSFET is used to sense the current on the inductor the
I
( L
MAX
Doc ID 18476 Rev 1
R
DS
)
I
( L
=
(
MAX
2
ON
I
( L
×
R
PK
)
I
I
IN
( L
SENSE
)
<
PK
(
=
)
MAX
0
=
R
1 .
V
)
1
SENSE
DS
×
=
)
−
I
2
2
=
=
LED
(
D
ON
×
×
2
MAX
2
I
1
LED
×
×
)
1
−
I
0
I
=
I
( L
( L
−
LED
D
1 .
PK
+
PK
R
D
MAX
×
100
DS
MAX
Δ
⎛
⎜
⎝
)
)
1
2
I
L
(
+
mV
ON
×
Δ
⎛
⎜ ⎜
⎝
2
I
)
1
L
+
⎞
⎟
⎠
Δ
2
I
L
⎞
⎟ ⎟
⎠
Application information
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