Supply Voltage (Max): 42V Frequency: - Type: Linear Internal Switch: None Topology: - Supply Voltage (Min): 5V High Bandwidth, Fast Fault Response Current Sensor IC
Supply Voltage (Max): 42V Frequency: - Type: Linear Internal Switch: None Topology: - Supply Voltage (Min): 5V High Bandwidth, Fast Fault Response Current Sensor IC
• Six LED current sinks rated up to 60 mA (A6274) or
120 mA (A6284)
• Total LED drive current—up to 360 mA or 720 mA
• Wide input voltage range of 5 to 42 V for start/stop, cold-
crank, and load-dump requirements
• Low-dropout voltage—drives two series WLEDs from
7 V input
• Gate driver for external ballast P-MOSFET
• LEDs combined in two groups with separate ENx and
ISETx
• LED current level set by external reference resistors
• Internal or external PWM dimming
• Controlled output drivers slew during PWM for lower
EMI
• Fault detection features: LED string open, LED pin
short-to-ground, single LED short, VOUT short-to-
ground, VIN overvoltage, and thermal protection
• Input supply and temperature-based derating
• Automotive K-temperature range (–40°C to 150°C)
20-Pin eTSSOP (LP) with Exposed Thermal Pad
AEC-Q100 qualified
DESCRIPTION
The A6274 and A6284 are programmable linear current
regulator ICs for driving automotive LED arrays. The LED
current is programmed by external resistors. These devices
sink up to 60 mA (A6274) or 120 mA (A6284), from each of
six LED pins, to drive strings of high-brightness LEDs. LED
pins can be paralleled to drive even higher current LED strings.
Current settings are typically accurate to 2%, while typical
matching between LED strings is 0.8%.
LED light output can be adjusted by PWM dimming. The ICs
provide an internal PWM dimming circuit that is programmed
by external resistors for PWM frequency and duty cycle. It
can also accept an external PWM signal. Multiple ICs can be
configured in parallel for larger lighting systems. An internal
FULL (V
DR
> 3.6 V) option is provided to override the PWM-
dimming ratio for full LED current.
LED current derating with temperature and programmable
VIN levels allows operation over a wide range of operating
conditions.
Continued on next page...
PACKAGES:
APPLICATIONS
• Automotive rear combination light
• DRL/position
• General automotive lighting
Not to scale
Q1
C2
DIM
FULL
D1
D2
D3
R1
C5
R3
FFn
R6
EN1
EN2
R2
R4
R5
R7
R8
R9
C1
GATE
VIN
EN1
EN2
BIAS
VTH
FFn
C3
C4
COMP
OUT
LED1
LED2
LED3
LED4
LED6
GND
A6274-84
LED5
DR
PWMIN
ISET1
ISET2
Figure 1: Typical Application Diagram for “-1” Latching Version
A6274-84-DS, Rev. 2
January 3, 2017
A6274, A6274-1
A6284, A6284-1
DESCRIPTION (continued)
Linear Current Regulator and Controller
for Automotive LED Arrays
A GATE pin is provided to drive an external P-channel MOSFET,
which serves as an active ballast resistor to reduce the heat dissipation
within the IC package. It also serves as an input disconnect switch
in the event of an LED string short-to-ground fault.
The A6274 and A6284 provide a non-latching option while the
A6274-1 and A6284-1 provide a latching option.
SPECIFICATIONS
SELECTION GUIDE
Part Number
A6274KLPTR-T
A6284KLPTR-T
A6274KLPTR-1-T
A6284KLPTR-1-T
1
Contact Allegro
™
I
LED(MAX)
60 mA per channel
120 mA per channel
60 mA per channel
120 mA per channel
FAULT Response
(see Table 2 for details)
Unlatched MODE0
Unlatched MODE0
Latched MODE1
Latched MODE1
Package
Packing
[1]
20-pin eTSSOP with thermal pad
4,000 pieces per 13-in. reel
for additional packing options.
ABSOLUTE MAXIMUM RATINGS
[2]
Characteristic
VIN, OUT, DR, EN1, EN2, COMP, FFn
GATE
LED1 to LED6
All other pins
Junction Temperature
Transient Junction Temperature
Storage Temperature Range
2
Stresses
Symbol
V
IN
, V
OUT
,
V
COMP
, V
DR
,
V
EN1
, V
EN2
, V
FFn
V
GATE
V
LEDx
T
J
T
Jt
T
stg
Notes
Rating
−0.3 to 45
Max of (–0.3 or
V
IN
– 9) to 45
−0.5 to 45
−0.3 to 6.5
−40 to 150
Unit
V
V
V
V
°C
°C
°C
Overtemperature event not exceeding 10 seconds, lifetime
duration not exceeding 10 hours, determined by design
characterization.
175
−55 to 150
beyond those listed in this table may cause permanent damage to the device. The absolute maximum ratings are stress ratings only, and functional operation of
the device at these or any other conditions beyond those indicated in the Electrical Characteristics table is not implied. Exposure to absolute-maximum-rated conditions for
extended periods may affect device reliability.
THERMAL CHARACTERISTICS
Characteristic
Junction-to-Ambient Thermal Resistance
3
Additional
Symbol
R
θJA
Test Conditions
[3]
Estimated, on 4-layer PCB based on JEDEC standard
Value
29
Unit
°C/W
thermal information available on the Allegro website.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
A6274, A6274-1
A6284, A6284-1
Linear Current Regulator and Controller
for Automotive LED Arrays
PINOUT DIAGRAM AND TERMINAL LIST TABLE
Terminal List Table
ISET1
ISET2
VTH
PWMIN
BIAS
FFn
LED1
LED2
LED3
GND
1
2
3
4
5
PAD
6
7
8
9
10
15
14
13
12
11
COMP
OUT
LED6
LED5
LED4
5
BIAS
4
PWMIN
3
VTH
20
19
18
17
16
DR
EN2
EN1
VIN
Number
1
Symbol
ISET1
Function
Sets LEDx sink current for LED1-3. Connect
resistor to GND to set current, up to 60 mA
(A6274) or 120 mA (A6284) per channel.
Sets LEDx sink current for LED4-6. Connect
resistor to GND to set current, up to 60 mA
(A6274) or 120 mA (A6284) per channel.
Connect ISET2 to BIAS if only one resistor
setting is required for LED1-6.
Sets input voltage threshold for current foldback
and V
OUT
threshold for open-LED fault (D, E, F,
and G) disable threshold.
PWM frequency setting. Internal PWM frequency
set when connected to GND through a resistor
and uses external PWM when a logic signal is
applied to this pin.
Output of internal bias regulator. Connect a
1 µF decoupling capacitor near to IC pin. BIAS
pin can deliver up to 7 mA to an external load.
Active-low fault flag. This pin can be used as
an input pin while using “-1” latching version. If
pulled low, IC will turn all LEDs off for one-out-
all-out functionality across multiple chips in the
system.
Three LED current sinks. Connect the cathode of
each LED string to these pins.
Ground pin.
Three LED current sinks. Connect the cathode of
each LED string to these pins.
Connect to drain of series-pass MOSFET.
Connect a 470 nF capacitor across COMP pin
and drain node of external PMOS. If PMOS is
not used, connect this pin to VIN.
Gate drive for series-pass MOSFET. If PMOS is
not used, connect this pin to VIN.
Input voltage to IC. Connect to source of series-
pass P-channel MOSFET. Connect a decoupling
capacitor close to this pin.
Active-high-enable input for LED1-3.
Active-high-enable input for LED4-6.
Voltage on this pin sets dimming duty cycle
when 0 < V
DR
< 3.6 V. IC operates with 100%
duty cycle in internal and external PWM mode
when V
DR
> V
DRDC
(max)
Thermal pad. Solder to ground plane for better
thermal performance.
2
ISET2
GATE
Package LP, 20-Pin eTSSOP Pinout Diagram
6
FFn
7, 8, 9
10
11, 12, 13
14
15
16
17
18
19
20
LED1-3
GND
LED4-6
OUT
COMP
GATE
VIN
EN1
EN2
DR
–
PAD
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
3
A6274, A6274-1
A6284, A6284-1
VIN
Linear Current Regulator and Controller
for Automotive LED Arrays
GATE
COMP OUT
A6274-84
VBIAS
LDO
V
OUT Short
EN1
EN1
EN2
EN2
Feedback
and Control
FULL
6
LED1
ON/OFF
LED2
Internal
PWM
Generator
VTH
DR
PWMIN
LED3
EN1
LED4
ISET2
Reference
Current
ISET1
TSD
FFn
Fault
Driver
OUT Short
EN2
LED5
LED
Open/
Short
Detect
6
LED6
GND
Functional Block Diagram
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
A6274, A6274-1
A6284, A6284-1
Linear Current Regulator and Controller
for Automotive LED Arrays
ELECTRICAL CHARACTERISTICS:
Valid at V
IN
= 14 V, V
ENx
= 3.3 V; ● indicates specifications across the full operating temperature
Characteristics
INPUT SPECIFICATIONS
Operating Input Voltage Range
Input Quiescent Current
[1]
Input Sleep Supply Current
[1]
INTERNAL BIAS CIRCUIT
BIAS Pin Voltage
BIAS Pin Dropout
V
BIAS
Undervoltage Release Threshold
V
BIAS
Undervoltage Lockout Stop Threshold
V
BIAS
V
BIASDROP
V
BIASSTART
V
BIASSTOP
I
BIAS
= 0 to 7 mA, 5.6 V ≤ V
IN
≤ 18 V
Minimum voltage drop across VIN and
BIAS pins. I
BIAS
< 7 mA, V
IN
= 5 V
V
IN
rising
V
IN
falling
Due to on-chip current limit, 10 V < V
IN
< 18 V
Due to on-chip current limit, V
IN
= 5 V
V
IN
– V
GATE
, V
LEDx
= 0.3 V
V
IN
– V
GATE
, V
LEDx
= 1 V
Voltage measured (V
IN
– V
GATE
) at end of
startup to detect PMOS connected
A6274; not in derating
A6284; not in derating
Measured at I
LED(MAX)
, LEDx mismatch < 0.5 V,
5 V < V
IN
< 18 V, T
J
= 0°C to 150°C
ISET2 connected to BIAS; compared to
average I
LEDx
, measured at I
LED(MAX)
, LEDx
mismatch < 1 V, 5 V < V
IN
< 18 V
A6274
A6284
A6274
A6284
A6274
A6284
I
LEDx
10% to 90% and 90% to 10%
A6274
A6284
0.015 mA ≤ I
ISETx
≤ 0.3 mA
●
●
●
●
●
●
●
●
4.75
–
–
–
4
2
8
–
–
5
0.3
–
–
–
–
10
130
600
5.25
–
4.6
4.2
–
–
12
360
–
V
IN
I
Q
I
QSLEEP
V
ENx
= high, FULL mode
V
EN1
= V
EN2
= 0 V; V
DR
= V
BIAS
●
●
5
–
–
–
–
–
42
6
6
Symbol
Test Conditions
Min.
Typ.
Max.
range with T
J
= –40°C to 150°C; other specifications are at T
J
= 25°C, unless noted otherwise. Refer to Figure 1 for typical application circuit.
Supply Voltage (Max): 42V Frequency: - Type: Linear Internal Switch: None Topology: - Supply Voltage (Min): 5V High Bandwidth, Fast Fault Response Current Sensor IC
Supply Voltage (Max): 42V Frequency: - Type: Linear Internal Switch: None Topology: - Supply Voltage (Min): 5V 120KHz Frequency, High Voltage Isolated Current Sensor with Overload Current Detection
Supply Voltage (Max): 42V Frequency: - Type: Linear Internal Switch: None Topology: - Supply Voltage (Min): 5V
Supply Voltage (Max): 42V Frequency: - Type: Linear Internal Switch: None Topology: - Supply Voltage (Min): 5V
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