BCR320U / BCR321U
LED Driver
Features
•
Continuous output current up to 250mA
with external resistor
•
Supply voltage up to 24V
•
Digital PWM input up to 10kHz frequency (BCR321U)
•
Up to 1W power dissipation in a small SC74 package
•
Negative thermal coefficient reduces output current
at higher temperatures
•
Easy paralleling of drivers to increase current
•
PB-free (RoHS compliant) package
•
Automotive qualified according to AEC Q101
Applications
•
Architectural LED lighting
•
Channel letters for advertising, LED strips for decorative lighting
•
Retail lighting in fridge, freezer case and vending machines
•
Emergency lighting (e.g. steps lighting, exit way signs etc.)
5
6
1
4
2
3
General Description
The BCR320U/BCR321U provide a low-cost solution for driving 0.5W LEDs with a typical
LED current ILED of 150mA to 200mA. Internal breakdown voltage is >16V, this is the
maximum voltage that the LED driver IC can sustain when the ouput is directly connected
to supply voltage. The BCR320U/BCR321U can be operated at supply voltages of 16V or
higher, by regarding the voltage drop of the LED load, which reduces the supply voltage
to the maximum output voltage of the driver.
The enable pin (BCR320) can withstand a maximum voltage of 25 V, which can also be
increased by stacking a series in front of the LED drivers, resulting in a certain voltage
drop of the LEDs, reducing the voltage at the enable pin below 25V.
A digital input pin (BCR321U) allows dimming via a Microcontroller
with frequencies of up to 10 kHz.
A reduction of the output current at higher temperatures is the result of the negative
temperature coefficient of 0.2 %/K. of the LED drivers.
With no need for additional external components like inductors, capacitors and
free wheeling diodes, the BCR320U/BCR321U LED drivers are a cost-efficient and
PCB-area saving solution for driving 0.5W LEDs.
1
2010-01-15
BCR320U / BCR321U
Electrical Characteristics
at
T
A
=25°C, unless otherwise specified
Parameter
Characteristics
Collector-emitter breakdown voltage
Symbol
min.
Values
typ.
-
max.
-
V
mA
-
-
1.2
1.2
350
90
-
-
500
105
-
Ω
kΩ
-
-
10
1.5
10
10
250
250
0.95
-
-
mA
8
8
-
-
12
12
-
-
1.05
V
Unit
V
BR(CEO)
I
EN
16
I
C
= 1 mA,
I
B
= 0
Enable current
V
EN
= 12 , BCR320U
V
EN
= 3.3 , BCR321U
DC current gain
h
FE
R
int
R
B
200
65
I
C
= 50 mA,
V
CE
= 1 V
Internal resistor
I
Rint
= 10 mA
Bias resistor
BCR320U
BCR321U
Output current
I
out
V
out
= 1.4 V,
V
EN
= 12 V, BCR320U
V
out
= 1.4 V,
V
EN
= 3.3 V, BCR321U
V
out
= 1.4 V,
V
EN
= 12 V,
R
EXT
= 3
Ω,
BCR320U
V
out
= 1.4 V,
V
EN
= 3.3 ,
R
EXT
= 3
Ω,
BCR321U
Voltage drop (V
Rext
)
V
drop
0.85
I
C
= 10 mA
DC Characteristics with stabilized LED load
Lowest sufficient supply voltage overhead
V
Smin
∆
I
out
/I
out
-
1.4
-
V
%/K
I
out
> 18mA
Output current change versus
T
A
V
EN
= 12 V;
V
out
> 2.0 V, BCR320U
V
EN
= 3.3 V;
V
out
> 2.0 V, BCR321U
Output current change versus
V
S
∆
I
out
/I
out
-
-
-
-
3
-0.2
-0.2
1
1
-
-
%/V
-
-
2010-01-15
V
EN
= 12 V;
V
out
> 2.0 V, BCR320U
V
EN
= 3.3 V;
V
out
> 2.0 V, BCR321U
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