MIC3201
High Brightness LED Driver with
High-Side Current Sense
General Description
The MIC3201 is a hysteretic step-down, constant-current,
High-Brightness LED (HB LED) driver capable of driving
up to four, 1A LEDs. It provides an ideal solution for
interior/exterior lighting, architectural and ambient lighting,
LED bulbs, and other general illumination applications.
The MIC3201 operates with an input voltage range from
6V to 20V. The hysteretic control gives good supply
rejection and fast response during load transients and
PWM dimming. The high-side current sensing and on-chip
current sense amplifier delivers LED current with ±5%
accuracy. An external high-side current sense resistor is
used to set the output current.
The MIC3201 offers a dedicated PWM input (DIM) which
enables a wide range of pulsed dimming. A high switching
frequency operation up to 1MHz allows the use of smaller
external components minimizing space and cost.
The MIC3201 operates over a junction temperature range
of -40°C to +125°C and is available in an 8-pin ePAD
SOIC package.
Datasheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
6.0V to 20V input voltage range
High efficiency (>90%)
± 5% LED current accuracy
High-side current sense
Dedicated dimming control input
Hysteretic control (no compensation!)
1A internal power switch
Up to 1MHz switching frequency
Adjustable constant LED current
5V on board regulator
Over temperature protection
–40°C to +125°C junction temperature range
Available in an 8-Pin ePAD SOIC package
Applications
•
•
•
•
•
•
Architectural, industrial, and ambient lighting
LED bulbs
Indicators and emergency lighting
Street lighting
Channel letters
12V lighting systems (MR-16 bulbs, under cabinet
lighting, garden/pathway lighting)
_________________________________________________________________________________________________________________________
Typical Application
MIC3201 Step-down LED Driver Circuit
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 •
http://www.micrel.com
February 2011
M9999-021011-B
Micrel, Inc.
MIC3201
Ordering Information
(1)
Part Number
MIC3201YME
Note:
1. YME is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
®
Marking
MIC3201YME
Junction Temp. Range
-40°C to +125°C
Package
8-Pin ePAD SOIC
Lead Finish
Pb-Free
Pin Configuration
8-Pin ePAD SOIC (ME)
Pin Description
Pin Number
1
Pin Name
VCC
Pin Function
Voltage Regulator Output. The V
CC
pin supplies the power to the internal circuitry. The VCC in
the output of a linear regulator which is powered from VIN. A 1µF ceramic capacitor is
recommended for bypassing and should be placed as close as possible to the VCC and AGND
pins. Do not connect to an external load.
Current Sense Input. The CS pin provides the high-side current sense to set the LED current
with an external sense resistor.
Input Power Supply. VIN is the input supply pin to the internal circuitry and the positive input to
the current sense comparator. Due to the high frequency switching noise, a 10µF ceramic
capacitor is recommended to be placed as close as possible to VIN and the power ground
(PGND) pin for bypassing. Please refer to layout recommendations.
Ground pin for analog circuitry. Internal signal ground for all low power sections.
Enable Input. The EN pin provides a logic level control of the output and the voltage has to be
2.0V or higher to enable the current regulator. The output stage is gated by the DIM pin. When
the EN pin is pulled low, the regulator goes to off state and the supply current of the device is
greatly reduced (below 1µA). In the off state, the output drive is placed in a "tri-stated" condition,
where MOSFET is in an “off” or non-conducting state. Do not drive the EN pin above the supply
voltage.
PWM Dimming Input. The DIM pin provides the control for brightness of the LED. A PWM input
can be used to control the brightness of LED. DIM high enables the output and its voltage has to
be at least 2.0V or higher. DIM low disables the output, regardless of EN “high” state.
Power Ground pin for Power FET. Power Ground (PGND) is the ground path for the high current
hysteretic mode. The current loop for the power ground should be as small as possible and
separate from the Analog ground (AGND) loop. Refer to the layout considerations for more
details.
Drain of Internal Power MOSFET. The LX pin connects directly to the inductor and provides the
switching current necessary to operate in hysteretic mode. Due to the high frequency switching
and high voltage associated with this pin, the switch node should be routed away from sensitive
nodes.
Connect to PGND.
2
3
CS
VIN
4
5
AGND
EN
6
DIM
7
PGND
8
LX
EP
GND
February 2011
2
M9999-021011-B
Micrel, Inc.
MIC3201
Absolute Maximum Ratings
(1)
V
IN
, V
CS
to PGND/AGND ................................ -0.3V to +22V
V
DIM
, V
EN
to PGND/AGND ..................................-0.3V to V
IN
V
LX
to PGND/AGND ................................. -0.3V to V
IN
+1.0V
V
CC
to PGND/AGND ..................................... -0.3V to +7.0V
V
CS
to V
IN
...................................................................... 0.3V
V
PGND
to V
AGND
............................................... -0.3V to +0.3V
Storage Temperature (Ts).........................–60°C to +150°C
Lead Temperature (Soldering, 10sec) ....................... 260°C
ESD Ratings (HBM)
(3)
...... ................................………..2kV
(MM)
(3)
......................... ...........................100V
Operating Ratings
(2)
Supply Voltage (V
IN
).......................................... 6.0V to 20V
Junction Temperature (T
J
) .........................-40°C to +125°C
Junction Thermal Resistance
SOIC (θ
JA
) ..........................................................41°C/W
SOIC (θ
JC
).......................................................14.7°C/W
Electrical Characteristics
(4)
V
IN
= 12V, V
DIM
= V
EN
= V
IN
, C
VCC
= 1µF,
bold
values indicate –40°C≤ T
J
≤
+125°C, unless noted.
Typical values are at T
A
= +25°C.
Symbol
V
IN
I
S
I
SD
V
CS(MAX)
V
CS(MIN)
V
HYS
Parameter
Operating Input Voltage Range
Supply Current
Shut Down Supply Current
Sense Voltage Threshold High
Sense Voltage Threshold Low
Current Sense Hysteresis
Current Sense Response Time
CS Pin Input Current
R
DSON
F
MAX
VCC
EN
HI
EN
LO
Internal Switch R
ON
Maximum Switching Frequency
VCC Regulator
EN Input Voltage High
EN Input Voltage Low
EN Input Current High
EN Input Leakage Low
DIM
HI
DIM
LO
DIM Input Voltage High
DIM Input Voltage Low
DIM Input Current High
DIM Input Leakage Low
F
DIM
T
LIM
T
LIMHYS
Maximum DIM Frequency
LX Pin Leakage Current
Over-Temperature Shutdown
Over-Temperature Shutdown Hysteresis
Start-up Time
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
4. Specification for packaged product only.
Condition
LX open
V
EN
= 0V
V
IN
- V
CS
V
IN
- V
CS
V
CS
Rising
V
CS
Falling
V
IN
- V
CS
= 200mV
T
A
= 25ºC
Min
6.0
Typ
1.2
Max
20.0
1.75
1
224
189
Units
V
mA
µA
mV
mV
mV
ns
ns
206
171
35
100
60
3
300
6
2.0
0.4
550
1.0
µA
mΩ
MHz
V
V
V
µA
µA
V
V
µA
µA
kHz
µA
ºC
ºC
µs
V
EN
=12V
V
EN
= 0V
2.0
30
50
1
0.4
V
DIM
=12V
V
DIM
= 0V
V
IN
- V
CS
≥
250mV
V
LX
=V
IN
22
30
1
20
5
165
20
From EN Pin going high,
DIM = 12V, C
VCC
= 1µF
300
February 2011
3
M9999-021011-B
Micrel, Inc.
MIC3201
Typical Characteristics
1 LED Efficiency
vs. Input Voltage
1A
90
80
70
EFFICIENCY (%)
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
2 LED Efficiency
vs. Input Voltage
1A
1200
1000
1 LED Current
vs. Input Voltage
1A
50
40
30
20
10
0
5
10
ILED (mA)
60
350mA
350mA
800
600
400
200
0
350mA
15
20
5
10
15
20
5
10
15
20
INPUT VOTLAGE (V)
INPUT VOTLAGE (V)
INPUT VOTLAGE (V)
1200
1000
2 LED Current
vs. Input Voltage
1.4
SUPPLY CURRENT (mA)
1.2
1.0
0.8
0.6
0.4
0.2
0.0
5
10
15
20
5
Supply Current
vs. Input Voltage
0.050
SHUTDOWN CURRENT (uA)
0.045
0.040
0.035
0.030
0.025
0.020
0.015
0.010
0.005
0.000
10
15
20
Shutdown Current
vs. Input Voltage
1A
ILED (mA)
800
600
400
200
0
INPUT VOTLAGE (V)
350mA
T
A
= 25°C
T
A
= 25°C
5
10
15
20
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Switching Frequency
vs. Input Voltage
SWITCHING FREQUENCY (kHz)
800
Enable Threshold
vs. Input Voltage
1.6
ENABLE THRESHOLD (V)
1.4
1.2
VCC (V)
1.0
0.8
0.6
0.4
0.2
0.0
5
10
T
A
= 25°C
VCC
vs. Input Voltage
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
T
A
= 25°C
700
600
500
400
300
200
100
0
5
10
15
20
INPUT VOLTAGE (V)
R
CS
= 0.2Ω
L = 22µH
T
A
= 25°C
15
20
5
10
15
20
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Current Sense Voltage
vs. Input Voltage
250
V
CS(Max)
VCC
vs. ICC
7.0
SWITCH VOLTAGE (mV)
6.0
5.0
VCC (V)
350
300
250
200
150
100
50
0
0
Switch Voltage
vs. Switch Current
CURRENT SENSE (mV)
200
150
100
50
0
5
10
15
20
INPUT VOLTAGE (V)
V
CS(Min)
4.0
3.0
2.0
1.0
0.0
0
5
10
ICC (mA)
15
20
T
A
= 25°C
T
A
= 25°C
0.25
0.5
0.75
1
SWITCH CURRENT (A)
February 2011
4
M9999-021011-B
Micrel, Inc.
R
DSON
vs. Input Voltage
THERMAL SHUTDOWN (°C)
MIC3201
Thermal Shutdown
vs. Input Voltage
ON
400
350
300
R
DS(ON)
(mΩ)
250
200
150
100
50
0
5
180
160
140
120
100
80
60
40
20
0
5
6.0
ON
UVLO Threshold
vs. Temperature
UVLO THRESHOLD (V)
5.0
4.0
3.0
2.0
1.0
0.0
OFF
OFF
I
OUT
= 1A @ 25°C
10
15
20
10
15
20
-40 -20
0
20
40
60
80 100 120
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
TEMPERATURE (°C)
60
50
40
30
20
10
0
5
T
CASE
@ 1.0A
vs. Input Voltage
SUPPLY CURRENT (mA)
Supply Current
vs. Temperature
2.0
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-40 -20
0
20
40
60
80 100 120
1.6
ENABLE THRESHOLD (V)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-40 -20
Enable Threshold
vs. Temperature
ON
1.8
V
IN
= 12V
1 LED
T
CASE
(ºC)
OFF
10
15
20
INPUT VOTLAGE (V)
TEMPERATURE (°C)
0
20
40
60
80 100 120
TEMPERATURE (°C)
Shutdown Current
vs. Temperature
SWITCHING FREQUENCY (kHz)
Switching Frequency
vs. Temperature
800
700
600
500
400
300
200
100
0
-40 -20
0
20
40 60 80 100 120
TEMPERATURE (°C)
12V Input
R
CS
= 0.2Ω
L = 22µH
35
SHUTDOWN CURRENT (uA)
30
25
20
15
10
5
0
-40 -20
0
20 40 60
80 100 120
TEMPERATURE (°C)
V
IN
= 12V
500
450
400
R
DS(ON)
(mΩ)
350
300
250
200
150
100
50
0
Low-Side MOSFET R
DS(ON)
vs. Temperature
V
IN
= 12V
-40 -20
0
20
40 60 80 100 120
TEMPERATURE (°C)
VCC
vs. Temperature
7.0
CURRENT SENSE (mV)
250
200
150
100
50
Current Sense Voltage
vs. Temperature
V
C(Max)
6.0
5.0
VCC (V)
4.0
3.0
2.0
1.0
0.0
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
V
IN
= 12V
V
CS(Min)
V
HYS
0
-40 -20
0
20
40 60 80 100 120
TEMPERATURE (°C)
February 2011
5
M9999-021011-B
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