MIC3202/MIC3202-1
High-Brightness LED Driver with
Integrated MOSFET and High-Side
Current Sense
General Description
The MIC3202 is a hysteretic, step-down, constant-current,
High-Brightness LED (HB LED) driver. It provides an ideal
solution for interior/exterior lighting, architectural and
ambient lighting, LED bulbs, and other general illumination
applications.
The MIC3202 is well suited for lighting applications
requiring a wide-input voltage range. 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 MIC3202 offers a dedicated PWM input (DIM) which
enables a wide range of pulsed dimming. High-frequency
switching operation of up to 1MHz allows the use of
smaller external components, minimizing space and cost.
The MIC3202 offers a frequency dither feature for low-EMI
applications.
The MIC3202 operates over a junction temperature from
−40°C
to
+125°C
and is available in an 8-pin e-PAD SOIC
package.
A dither disabled version MIC3202-1 is also available in
the same package as the MIC3202.
Datasheets and support documentation can be found on
Micrel’s web site at:
www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
•
•
6V to 37V input voltage range
High efficiency (>90%)
±5%
LED current accuracy
MIC3202: Dither enabled for low EMI
MIC3202-1: Dither disabled
High-side current sense (up to 1A)
Dedicated dimming control input
Hysteretic control (no compensation required)
Up to 1MHz switching frequency
Adjustable constant LED current
Over-temperature protection
−40°C
to
+125°C
junction temperature range
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
Efficiency
vs. Input Voltage
100
6LED
4LED
8LED
EFFICIENCY (% )
95
2LED
90
85
I
LED
= 1A
L = 47uH
80
6
14
22
30
38
INPUT VOLTAGE (V)
MIC3202 Step-Down LED Driver
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 •
http://www.micrel.com
September 2010
M9999-091710-A
Micrel, Inc.
MIC3202/MIC3202-1
Ordering Information
(1)
Part Number
MIC3202YME
MIC3202-1YME
Note:
1.
YM is a GREEN RoHS-compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
®
Marking
MIC3202YME
MIC3202-1YME
Junction Temperature Range
−40°C
to
+125°C
−40°C
to
+125°C
Package
8-Pin SOIC
8-Pin SOIC
PWM
Dither
Non-Dither
Pin Configuration
8-Pin ePAD SOIC
MIC3202/MIC3202-1
Pin Description
Pin
Number
1
2
Pin Name
VCC
CS
Pin Function
Voltage Regulator Output. The VCC pin supplies the power to the internal circuitry. The VCC is 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.
Current-Sense Input. The CS pin provides the high-side current sense to set the LED current using an
external sense resistor.
Input Power Supply. The VIN pin 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 1µF ceramic capacitor is
recommended to be placed as close as possible to VIN pin 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. The voltage has to be 2.0V or higher
to enable the current regulator. The output stage is also gated by the DIM input. 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).
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 Internal Power FET. Power Ground (PGND) is the ground path for the high current.
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.
3
4
5
VIN
AGND
EN
6
DIM
7
PGND
8
EP
LX
GND
September 2010
2
M9999-091710-A
Micrel, Inc.
MIC3202
Absolute Maximum Ratings
(1, 2)
V
IN
to PGND ..................................................
−0.3V
to
+42V
V
LX
to PGND........................................
−0.3V
to (V
IN
+
0.6V)
V
CS
to PGND .......................................
−0.3V
to (V
IN
+
0.3V)
V
EN
to AGND .......................................
−0.3V
to (V
IN
+
0.3V)
V
DIM
to AGND ......................................
−0.3V
to (V
IN
+
0.3V)
V
CC
to PGND ................................................
−0.3V
to
+6.0V
PGND to AGND ..........................................
−0.3V
to
+
0.3V
Junction Temperature ................................................ 150°C
Storage Temperature Range ....................
−60°C
to
+150°C
Lead Temperature (Soldering, 10sec) ....................... 260°C
Operating Ratings
(3)
Supply Voltage (V
IN
).......................................... 6.0V to 37V
Enable Voltage (V
EN)
.............................................. 0V to V
IN
Dimming Voltage (V
DIM
)
.................................................................
0V to V
IN
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
= V
EN
= V
DIM
= 12V; C
VCC
= 1.0µF; T
J
=
25°C,
bold
values indicate
−40°C ≤
T
J
≤ +125°C;
unless noted.
Symbol
V
IN
I
S
I
SD
UVLO
UVLO
HYS
VCC
V
CS(MAX)
V
CS(MIN)
Parameter
Input Voltage Range (V
IN
)
Supply Current
Shut Down Current
V
IN
UVLO Threshold
V
IN
UVLO Hysteresis
V
CC
Output Voltage
Current-Sense Upper Threshold
Current-Sense Lower Threshold
V
CS
Hysteresis
V
CSHYS
Current-Sense Response Time
Current-Sense Input Current
Frequency
F
MAX
V
DITH
F
DITHER
EN
HI
Maximum Switching Frequency
V
CS
Hysteresis Dithering Range
(5)
Frequency Dithering Range
EN Logic Level High
EN Logic Level Low
EN
LO
EN Bias Current
Start-up Time
V
EN
= 12V
V
EN
= 0V
From EN Pin going high to LX
going low
30
0.1
30
(5)
Condition
Min.
6.0
Typ.
Max.
37.0
Units
V
mA
µA
V
mV
Input Supply
LX Pin = open
V
EN
= 0V; T
J
= from -40ºC to 85ºC
V
IN
Rinsing
3.2
1.2
0.05
4
500
V
CS
= V
IN
= 12V, I
CC
= 10mA
V
CS(MAX ) =
V
IN
−
V
CS
V
CS(MIN ) =
V
IN
−
V
CS
V
CS
Rising
V
CS
Falling
V
IN
- V
CS
= 200mV
4.5
199
165
5
212
177
35
60
40
3
1
±6
% of Switching Frequency
2.0
0.4
60
1
±12
5.5
225
189
1.75
5
4.5
VCC Supply
V
mV
mV
mV
ns
µA
MHz
mV
%
V
V
µA
µs
Current Limit
Dithering (MIC3202)
Enable Input
September 2010
3
M9999-091710-A
Micrel, Inc.
MIC3202
Electrical Characteristics
(4)
V
IN
= V
EN
= V
DIM
= 12V; C
VCC
= 1.0µF; T
J
= 25°C, bold values indicate
−40°C ≤
T
J
≤ +125°C;
unless noted.
Symbol
DIM
HI
DIM
LO
f
DIM
Parameter
DIM Logic Level High
DIM Logic Level Low
DIM Bias Current
Maximum Dimming Frequency
MOSFET R
DS(ON)
LX Leakage Current
Over-Temperature Shutdown
Over-Temperature Shutdown Hysteresis
I
LX
= 200mA
V
EN
= 0V; V
IN
= V
LX
= 37V
T
J
Rising
275
5
160
20
V
DIM
= 12V
V
DIM
= 0V
20
0.1
Condition
Min.
2.0
0.4
35
1
20
625
50
Typ.
Max.
Units
V
V
µA
kHz
mΩ
µA
Dimming Input
Internal MOSFET
R
DS(ON)
Thermal Protection
T
LIM
T
LIMHYS
Notes:
1.
2.
3.
4.
5.
Exceeding the absolute maximum rating may damage the device.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
The device is not guaranteed to function outside its operating rating.
Specification for packaged product only.
Guaranteed by design.
°C
September 2010
4
M9999-091710-A
Micrel, Inc.
MIC3202
Typical Characteristics
Efficiency
vs. Input Voltage
100
6LED
4LED
8LED
LED Current Normalized
vs. Input Voltage
1.02
LED CURRENT NORM (A)
I
LED
= 1A
L = 47uH
LED Current Accuracy
vs. Input Voltage
2.0%
I
LED
= 1A
L = 47uH
EFFICIENCY (% )
2LED
1.01
2LED
4LED
6LED
LED CURRENT (%)
95
90
85
80
75
6
I
LED
= 1A
L = 47uH
1LED
1.0%
2LED
4LED
6LED
1.00
8LED
0.0%
8LED
0.99
1LED
-1.0%
1LED
0.98
14
22
30
38
6
14
22
30
38
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
-2.0%
6
14
22
30
38
INPUT VOLTAGE (V)
Switching Frequency
vs. Input Voltage
1000
SWITCHING FREQUENCY (kHz)
I
LED
= 1A
L = 47uH
Duty Cycle
vs. Input Voltage
100%
4LED
2LED
6LED
8LED
V
IN
Supply Current
vs. Input Voltage
3.0
SUPPLY CURRENT (mA)
2.5
2.0
1.5
1.0
0.5
0.0
V
OUT
= OPEN
V
CC
= 5V
NO-SWITCHING
500
1LED
DUTY CYCLE (%)
750
75%
50%
1LED
250
2LED
4LED
6LED
8LED
25%
I
LED
= 1A
L = 47uH
0
6
14
22
30
38
INPUT VOLTAGE (V)
0%
6
14
22
30
38
INPUT VOLTAGE (V)
6
14
22
30
38
INPUT VOLTAGE (V)
V
IN
Shutdown Current
vs. Input Voltage
0.5
SHUTDOWN CURRENT (µA)
0.4
0.3
0.2
0.1
V
EN
= 0V
V
CC
Voltage
vs. Input Voltage
5.050
250
CS Voltage
vs. Input Voltage
V
LED
=3.5V
I
LED
=1A
V
CC
VOLTAGE (V)
CS VOLTAGE (mV)
5.025
225
V
CS MAX
5.000
200
V
CS MIN
4.975
V
LED
= OPEN
I
LED
= 0A
175
0.0
6
14
22
30
38
INPUT VOLTAGE (V)
4.950
6
14
22
30
38
INPUT VOLTAGE (V)
150
6
14
22
30
38
INPUT VOLTAGE (V)
Enable Bias Current
vs. Enable Voltage
125
100
75
50
25
0
6
14
22
30
38
ENABLE VOLTAGE (V)
V
IN
= V
EN
V
LED
=OPEN
I
LED
= 0A
Dimming Bias Current
vs. Dimming Voltage
100
DIMMING BIAS CURRENT (µA)
SWITCH R
DSON
(mΩ)
425
Switch R
DSON
vs. Input Voltage
ENABLE BIAS CURRENT (µA)
75
375
50
325
25
V
IN
= V
DIM
V
LED
=OPEN
I
LED
= 0A
275
V
LED
= 3.5V
I
LED
= 1A
0
6
14
22
30
38
DIMMING VOLTAGE (V)
225
6
14
22
30
38
INPUT VOLTAGE (V)
September 2010
5
M9999-091710-A
stm32/stm8
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