MIC3203/MIC3203-1
High-Brightness LED Driver Controller
with High-Side Current Sense
General Description
The MIC3203 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 MIC3203 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 MIC3203 offers a dedicated PWM input (DIM) which
enables a wide range of pulsed dimming. A high-frequency
switching operation up to 1.5MHz allows the use of smaller
external components minimizing space and cost. The
MIC3203 offers frequency dither feature for EMI control.
The MIC3203 operates over a junction temperature from
−40°C
to
+125°C
and is available in an 8-pin SOIC
package.
A dither disabled version MIC3203-1 is also available in
the same package as the MIC3203.
Datasheets and support documentation can be found on
Micrel’s web site at:
www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
•
•
4.5V to 42V input voltage range
High efficiency (>90%)
±5%
LED current accuracy
MIC3203: Dither enabled for low EMI
MIC3203-1: Dither disabled
High-side current sense
Dedicated dimming control input
Hysteretic control (no compensation!)
Up to 1.5MHz 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
MIC3203 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
March 2010
M9999-032910-A
Micrel, Inc.
MIC3203
Ordering Information
(1)
Part Number
MIC3203YM
MIC3203-1YM
Note:
1. YM is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
®
Marking
MIC3203YM
MIC3203-1YM
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 SOIC
MIC3203/MIC3203-1
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, during this period 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 for the high-current switching with
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.
Gate-Drive Output. Connect to the gate of an external N-channel MOSFET. The drain of the external
MOSFET 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.
2
CS
3
4
VIN
AGND
5
EN
6
DIM
7
PGND
8
DRV
March 2010
2
M9999-032910-A
Micrel, Inc.
MIC3203
Absolute Maximum Ratings
(1)
V
IN
to PGND ..................................................
−0.3V
to
+45V
V
CC
to PGND ................................................
−0.3V
to
+6.0V
CS to PGND ........................................
−0.3V
to (V
IN
+
0.3V)
EN to AGND ........................................
−0.3V
to (V
IN
+
0.3V)
DIM to AGND ......................................
−0.3V
to (V
IN
+
0.3V)
DRV to PGND ....................................
−0.3V
to (V
CC
+
0.3V)
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
ESD Ratings
(3)
HBM ...................................................................... 1.5kV
MM .........................................................................200V
Operating Ratings
(2)
Supply Voltage (V
IN
).......................................... 4.5V to 42V
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
) .......................................................98.9°C/W
SOIC (θ
JC
).......................................................48.8°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
Parameter
Input Voltage Range (V
IN
)
Supply Current
Shutdown Current
V
IN
UVLO Threshold
V
IN
UVLO Hysteresis
V
CC
Output Voltage
V
IN
= 12V, I
CC
= 10mA
4.5
201.4
199
168
165
DRV = open
V
EN
= 0V
V
IN
rinsing
3.2
4
500
5
212
212
177
177
35
V
CS
Rising
V
CS
Falling
V
IN
−
V
CS
= 220mV
50
70
0.5
10
1.5
±6
% of Switching Frequency
±12
5.5
222.6
225
186
189
Condition
Min.
4.5
1
Typ.
Max.
42
3
1
4.5
Units
V
mA
µA
V
mV
V
mV
mV
mV
mV
mV
ns
ns
µA
MHz
mV
%
Input Supply
VCC Supply
Current Limit
V
CS(MAX)
V
CS(MIN)
V
CSHYS
Current Sense Upper Threshold
Sense Voltage Threshold Low
V
CS
Hysteresis
Current Sense Response Time
CS Input Current
Frequency
F
MAX
V
DITH
F
DITHER
Switching Frequency
V
CS
Hysteresis Dithering Range
(5)
Frequency Dithering Range
(5)
V
CS(MAX ) =
V
IN
−
V
CS
V
CS(MIN ) =
V
IN
−
V
CS
Dithering (MIC3203)
March 2010
3
M9999-032910-A
Micrel, Inc.
MIC3203
Electrical Characteristics
(4)
(Continued)
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
EN
HI
EN
LO
Parameter
EN Logic Level High
EN Logic Level Low
EN Bias Current
Start-Up Time
Dimming Input
DIM
HI
DIM
LO
DIM Logic Level High
DIM Logic Level Low
DIM Bias Current
DIM Delay Time
F
DIM
Maximum Dimming Frequency
Pull Up, I
SOURCE
= 10mA
Pull Down, I
SINK
= -10mA
Rise Time, C
LOAD
= 1000pF
Fall Time, C
LOAD
= 1000pF
T
J
Rising
2
1.5
13
7
160
20
20
V
DIM
= 0V
From DIM Pin going high to DRV
going high
450
20
2.0
0.4
50
1
V
V
µA
ns
kHz
V
EN
= 12V
V
EN
= 0V
From EN Pin going high to DRV
going high
30
Condition
Min.
2.0
0.4
60
1
Typ.
Max.
Units
V
V
µA
µA
µs
Enable Input
External FET Driver
DRV On-Resistance
DRV Transition Time
Thermal Protection
T
LIM
T
LIMHYS
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.
5. Guaranteed by design.
Ω
ns
Over-Temperature Shutdown
Over-Temperature Shutdown Hysteresis
°C
March 2010
4
M9999-032910-A
Micrel, Inc.
MIC3203
Typical Characteristics
Efficiency
vs. Input Voltage
100
Efficiency
vs Input Voltage
100
NORMALIZED LED CURRENTS (A)
1.03
Normalized LED Currents
vs. Input Voltage
L=150µH
ILED=1A
1.02
90
90
EFFICIENCY (%)
1.01
1LED
1
2LED
4LED
6LED
10LED
8LED
EFFICIENCY (%)
80
4LED
6LED
8LED
70
10LED
80
4LED
6LED
0.99
70
8LED
10LED
L=68µH
ILED=1A
0.98
L=150µH
ILED=1A
60
0
5
10
15
20
25
30
35
40
45
60
0
5
10
15 20 25 30
INPUT VOLTAGE (V)
35
40
45
0.97
0
5
10
15
20
25
30
35
40
45
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Normalized LED Currents
vs Input Voltage
1.03
Frequency
vs. Input Voltage
350
L=68µH
ILED=1A
Frequency
vs Input Voltage
700
L = 68µH
ILED = 1A
NORMALIZED LED CURRENTS (A)
L=150µH
ILED=1A
1.02
300
600
1.01
FREQUENCY (kHz)
250
4LED
200
FREQUENCY (kHz)
500
4LED
400
2LED
300
1LED
1
1LED
0.99
2LED
0.98
4LED
150
2LED
100
50
1LED
10LED
8LED
6LED
0
5
10
15
20
25
30
35
40
45
200
100
6LED
8LED
10LED
0.97
0
5
10
15
20
25
30
35
40
45
6LED
0
0
5
10
15
20
25
8LED
30
35
10LED
40
45
0
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Duty Cycle
vs. Input Voltage
100
100
Duty Cycle
vs Input Voltage
1.4
Supply Current
vs. Input Voltage
SUPPLY CURRENT (mA)
1.2
1.0
0.8
0.6
0.4
0.2
0.0
TA = 25°C
ILED = 0A
75
75
DUTY CYCLE (%)
50
1LED
2LED
4LED
DUTY CYCLE (%)
50
1LED
2LED
4LED
25
6LED
8LED
0
0
5
10
15
20
25
30
35
40
45
L=150µH
ILED=1A
25
6LED
8LED
L=68µH
ILED=1A
10
15
20
25
30
35
10LED
0
0
5
10LED
40
45
0
5
10
15
20
25
30
35
40
45
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
March 2010
5
M9999-032910-A
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