BCR402R
LED Driver
Features
•
LED drive current of 20mA
•
Output current adjustable up to 60mA with
external resistor
•
Supply voltage up to 18V
•
Easy paralleling of drivers to increase current
•
Low voltage overhead of 1.2V
•
High current accuracy at supply voltage variation
•
No EMI
•
Reduced output current at higher temperatures - negative thermal coefficient of -0.3% / K
•
RoHS compliant (pb-free) SOT143R package
•
Qualified according AEC Q101
Applications
•
Channel letters for advertising, LED strips for decorative lighting
•
Aircraft, train, ship illumination
•
Retrofits for general lighting, white goods like refrigerator lighting
•
Medical lighting
General Description
The BCR402R is a cost efficient LED driver to drive low power LED’s. The advantages
towards resistor biasing are:
•
homogenous light output despite varying forward voltages in different LED strings
•
homogenous light output of LED’s despite voltage drop across long supply lines
•
homogenous light output independent from supply voltage variations
•
longer lifetime of the LED’s due to reduced output current at higher temperatures
(negative thermal coefficient)
The advantages towards discrete solutions are:
•
lower assembly cost
•
smaller form factor
•
better quality due to less soldering points
•
higher output current accuracy due to pretested LED drivers
Dimming is possible by using an external digital transistor at the ground pin.
The BCR402R can be operated at higher supply voltages by putting LED’s between the
power supply +VS and the power supply pin of the LED driver. You can find further details
in the application note AN066.
The BCR402R is a perfect fit for numerous low power LED applications by combining small
form factor with low cost. These LED drivers offer several advantages to resistors like
significantly higher current control at very low voltage drop ensuring high lifetime of LED’s.
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2009-11-13
BCR402R
Electrical Characteristics
at
T
A
=25°C, unless otherwise specified
Parameter
Characteristics
Collector-emitter breakdown voltage
Symbol
min.
Values
typ.
-
440
150
38
20
0.76
max.
-
540
-
47
22
-
-
µA
-
Ω
mA
V
Unit
V
BR(CEO)
I
S
h
FE
R
int
I
out
V
drop
18
350
-
33
18
-
I
C
= 100 µA,
I
B
= 0
Supply current
V
S
= 10 V
DC current gain
I
C
= 50 mA,
V
CE
= 1 V
Internal resistor
I
Rint
= 10 mA
Output current
V
S
= 10 V,
V
out
= 7.6 V
Voltage drop (V
S
-
V
E
)
I
out
= 20 mA
DC Characteristics with stabilized LED load
Lowest sufficient supply voltage overhead
V
Smin
∆
I
out
/I
out
∆
I
out
/I
out
-
-
-
1.2
-0.3
2
-
-
-
V
%/K
%/V
I
out
> 8mA
Output current change versus
T
A
V
S
= 10 V
Output current change versus
V
S
V
S
= 10 V
3
2009-11-13
Microcontroller MCU
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