BCR402U
LED Driver
Features
•
LED drive current of 20mA
•
Output current adjustable up to 65mA with external resistor
•
Supply voltage up to 40V
•
Easy paralleling of drivers to increase current
•
Low voltage overhead of 1.4V
•
High current accuracy at supply voltage variation
•
No EMI
•
High power dissipation of 750mW
•
Reduced output current at higher temperatures - Negative thermal coefficient of -0.2% / K
•
RoHS compliant (pb-free) small and robust SC-74 package
•
Qualified according to 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
•
Automotive applications like CHMSL and rear combination lights
General Description
The BCR402U 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 BCR402U 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 AN097.
The BCR402U 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.
1
2009-07-31
5
6
1
4
2
3
BCR402U
Electrical Characteristics
at
T
A
=25°C, unless otherwise specified
Parameter
Characteristics
Collector-emitter breakdown voltage
Symbol
min.
Values
typ.
-
420
220
44
20
0.85
max.
-
500
470
53
22
0.9
V
µA
-
Ω
mA
V
Unit
V
BR(CEO)
I
S
h
FE
R
int
I
out
V
drop
40
340
100
37
18
0.8
I
C
= 1 mA,
I
B
= 0
Supply current
V
S
= 10 V
DC current gain
I
C
= 50 mA,
V
CE
= 1 V
Internal resistor
I
Rint
= 20 mA
Output current
V
S
= 10 V,
V
out
= 8.6 V
Voltage drop (V
S
-
V
E
)
I
C
= 20 mA
DC Characteristics with stabilized LED load
Lowest sufficient battery voltage overhead
V
Smin
∆
I
out
/I
out
∆
I
out
/I
out
-
-
-
1.4
-0.2
1
-
-
-
V
%/K
%/V
I
out
> 18mA
Output current change versus
T
A
V
S
= 10 V
Output current change versus
V
S
V
S
= 10 V
3
2009-07-31
Discrete Device
京公网安备 11010802033920号
EEWORLD
