MIC3223
High Power Boost LED Driver with
Integrated FET
General Description
The MIC3223 is a constant current boost LED driver
capable of driving a series string of high power LEDs. The
MIC3223 can be used in general lighting, bulb replacement,
garden pathway lighting and other solid state illumination
applications.
The MIC3223 is a peak current mode control PWM boost
regulator and the 4.5V and 20V operating input voltage
range allows multiple applications from a 5V or a 12V bus.
The MIC3223 implements a fixed internal 1MHz switching
frequency to allow for a reduction in the design footprint
size. Power consumption has been minimized through the
implementation of a 200mV feedback voltage that provides
an accuracy of ±5%. The MIC3223 can be dimmed through
the use of a PWM signal and features an enable pin for a
low power shutdown state.
The MIC3223 is a very robust LED driver and offers the
following protection features: over voltage protection (OVP),
thermal shutdown, switch current limiting and under voltage
lockout (UVLO).
The MIC3223 is offered in a low profile exposed pad 16-pin
TSSOP package.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
4.5V to 20V supply voltage
200mV feedback voltage with an accuracy of ±5%
Step-up output voltage (boost) conversion up to 37V
1MHz switching frequency
100mΩ/3.5A internal power FET switch
LEDs can be dimmed using a PWM signal
User settable LED current (through external resistor)
Externally programmable soft-start
Protection features that include:
– Output over-voltage protection (OVP)
– Under-voltage lockout (UVLO)
– Over temperature protection
•
Junction temperature range: -40°C to +125°C
•
Available in a exposed pad 16-pin TSSOP package
Applications
•
•
•
•
•
•
Architectural lighting
Industrial lighting
Signage
Landscape lighting (garden/pathway)
Under cabinet lighting
MR-16 bulbs
_______________________________________________________________________________________________________________________
Typical Application
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
January 2010
M9999-011510-A
Micrel, Inc.
MIC3223
Ordering Information
Part Number
MIC3223YTSE
Junction Temp. Range
–40° to +125°C
Package
16-pin ePad TSSOP
Lead Finish
PB- free
Pin Configuration
16-Pin ePad TSSOP (TSE)
Pin Description
Pin Number
1
2
Pin Name
EN
SS
Pin Function
Enable (Input): Logic high enables and logic low disables operation.
Soft Start (Input resistance of 30k). Connect a capacitor to GND for soft-start. Clamp the
pin to a known voltage to control the internal reference voltage and hence the output
current.
Compensation Pin (Input): Add external R and C-to-GND to stabilize the converter.
Negative Input to Error Amp
Connect to the centre tap of an external resistor divider, the top of which is tied to Vout
and bottom-to-ground.
Power Ground
Switch Node (Input): Internal NMOS switch Drain Pin
Input Supply
For 4.5V < VIN < 6V, connect DRVVDD to VIN. DRVVDD is the input voltage supply for
the converter’s internal power FET gate driver. For VIN > 6V, connect this pin to VDD.
For 4.5V < VIN < 6V, this pin becomes the input voltage supply for the converter’s internal
circuit. For VIN > 6V, this pin is an output of the internal 5.5V regulator that supplies
internal circuits. User must add 10µF decoupling capacitor from VDD-to-AGND.
PWM input to control LED dimming.
Output driver to drive external FET for LED dimming.
Analog Ground
Connect to Power Ground
3
4
5
6
7,8,9,10
11
12
13
COMP
FB
OVP
PGND
SW
VIN
DRVVDD
VDD
14
15
16
17
DIM_IN
DIM_OUT
AGND
EP
January 2010
2
M9999-011510-A
Micrel, Inc.
MIC3223
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) .....................................................+22V
Switch Voltage (V
SW
)..................................... -0.3V to +42V
Regulated Voltage (V
DD
) ............................... -0.3V to +6.5V
Dimming In Voltage (V
DIM_IN
) ...............-0.3V to (V
DD
+ 0.3V)
Dimming Out Voltage (V
DIM_OUT
)..........-0.3V to (V
DD
+ 0.3V)
Soft-Start Voltage (V
SS
) .......................-0.3V to (V
DD
+ 0.3V)
Enable Voltage (V
EN
)............................-0.3V to (V
IN
+ 0.3V)
Feedback Voltage (V
FB
) ......................-0.3V to (V
DD
+ 0.3V)
Switch Current (I
SW
) ..................................Internally Limited
Comp Voltage (V
COMP
).......................-0.3V to (+V
DD
+ 0.3V)
FET Driver Supply (V
DRVVDD
) ......................... -0.3V to +6.5V
PGND to AGND ............................................ -0.3V to +0.3V
Over Voltage Protection (V
OVP
) ...........-0.3V to (V
DD
+ 0.3V)
Peak Reflow Temperature (soldering, 10-20sec.) ..... 260°C
Storage Temperature (T
S
)..........................-65°C to +150°C
ESD Rating
(3)
................................................................+2kV
Operating Ratings
(2)
Supply Voltage (V
IN
)...................................... +4.5V to +20V
Switch Voltage (V
SW
)....................................................+37V
Junction Temperature (T
J
) .........................-40°C to +125°C
Junction Thermal Resistance
ePad TSSOP-16L (θ
JA
)...................................36.5°C/W
Electrical Characteristics
(4)
V
IN
= V
EN
= 12V; L = 22µH, C
IN
=4.7µF, C
OUT
=2x4.7µF; T
A
= 25°C,
BOLD
values indicate –40°C≤ T
J
≤
+125°C, unless otherwise noted.
Symbol
V
IN
V
UVLO
V
OVP
I
VIN
I
SD
V
FB
I
FB
V
DD
D
MAX
I
SW
R
SW
I
SW
V
EN
I
EN
V
DIM_TH_H
V
DIM_TH_L
Hys
I
DIM_IN
T
DR
T
DF
Parameter
Voltage Supply Range
Under Voltage Lockout
Over Voltage Protection
Quiescent Current
Shutdown Current
Feedback Voltage
Feedback Input Current
Internal Voltage Regulator
Maximum Duty Cycle
V
DD
Line Regulation
Switch Current Limit
Switch R
DSON
plus R
CS
Switch Leakage Current
Enable Threshold
Enable Pin Current
DIM_IN Threshold High
DIM_IN Threshold Low
DIM_IN Hysteresis
DIM_IN Pin Current
Dim Delay (Rising)
Dim Delay (Falling
V
DIM_IN
= 5V
DIM_IN Rising
DIM_IN Falling
40
30
Logic High
Logic Low
500
1
1.5
0.4
V
EN
=0, V
SW
=37V
Turn On
Turn Off
20
1.5
0.4
40
V
LED
=18V, V
IN
=8V to 16V, I
LED
=350mA
3.5
85
V
FB
=250mV
V
EN
=0V
Room Temperature
Over Temperature
V
FB
=200mV
190
184
-450
5.3
90
0.5
9
100
0.01
10
10.5
95
200
Monitoring for V
DD
Condition
Min
4.5
3
1.216
3.7
1.28
2.1
Typ
Max
20
4.4
1.344
5
10
210
216
Units
V
V
V
mA
µA
mV
mV
nA
V
%
%
A
mΩ
µA
V
V
µA
V
V
mV
µA
ns
ns
January 2010
3
M9999-011510-A
Micrel, Inc.
Symbol
DIM MIN
Parameter
Minimum Dimming Pulse
Condition
DIM_IN =1µs C
DIM_OUT
= 1.25nF
DIM_OUT measured from 4V rising to 2.5
falling
DIM_OUT pull up resistance
I
DIM_OUT
= +2mA
Dim Out pull down resistance
I
DIM_OUT
= -2mA
0.7
30
Temperature rising
Hysteresis
Min
0.7
0.5
70
40
1
46
165
10
1.3
62
Typ
Max
1.3
1.5
MIC3223
Units
µs
µs
Ω
Ω
MHz
kΩ
°C
°C
R
DO
R
DO
F
SW
R
SS
T
SD
Notes
DIM_OUT Resistance High
DIM_OUT Resistance Low
Oscillator Frequency
Soft Start Resistance
Over Temperature Threshold
Shutdown
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, 1.5kΩ in series with 100pF.
4. Specification for packaged product only.
Test Circuit
January 2010
4
M9999-011510-A
Micrel, Inc.
MIC3223
Typical Characteristics
Efficiency
v s. Input Voltage
98
96
94
EFFICIENCY (%)
92
90
88
86
84
82
80
5
10
15
20
INPUT VOLT AGE (V)
V
OUT
= 25V
I
OUT
= 0.5A
T = 25°C
VDD Voltage
v s. Input Voltage
5.50
5.45
5.40
VDD VOLTAGE (V)
5.35
5.30
5.25
5.20
5.15
5.10
5.05
5.00
5
10
15
20
INPUT VOLT AGE (V)
V
OUT
= 25V
I
OUT
= 0.5A
T = 25°C
CURRENT LIM IT (A)
9.0
9.5
Current Lim it
v s. Input Voltage
T = 25°C
8.5
8.0
7.5
V
IN
= 4.5V to 6V
7.0
4
9
14
19
INPUT VOLT AGE (V)
Feedback Voltage
v s. Input Voltage
0.210
0.208
SWITCHING FREQUENCY (MHz)
Switching Frequency
v s. Input Voltage
1.2
T = 25°C
Feedback Voltage
v s. Temperature
0.220
0.218
FEEDBACK VOLTAGE (V)
0.216
0.214
0.212
0.210
0.208
0.206
0.204
0.202
0.200
-40
-20
0
20
40
60
V
IN
= 12V
V
OUT
= 26V
I
OUT
= 0.36A
80
100 120
REFERENCE VOTLAG E (V)
0.206
0.204
0.202
0.200
0.198
0.196
0.194
0.192
0.190
4
9
14
19
INPUT VOLT AG E (V)
V
OUT
= 30V
I
OUT
=0.36A
1.1
1.1
1.0
V
DD
= V
IN
V
IN
= 4.5V to 6V
V
OUT
= 30V
I
OUT
= 0.36A
1.0
0.9
4
9
14
19
INPUT VOLT AGE (V)
T EM PERAT URE (°C)
Current Lim it
v s. Temperature
11.0
10.5
10.0
CURRENT LIM IT (A)
RSW_NO DE (Ω)
0.18
0.17
0.16
0.15
0.14
0.13
0.12
0.11
0.10
R
SW _NODE
vs.
T emperature
1.20
1.15
SWITCHING FREQUENCY (MHz)
Switching Frequency
v s. Temperature
9.5
9.0
8.5
8.0
7.5
7.0
6.5
6.0
-40
-20
0
20
40
60
80
100 120
T EM PERAT URE (°C)
V
IN
= 12V
1.10
1.05
1.00
0.95
0.90
0.85
0.80
-40
-20
0
20
40
60
80
100 120
T EM PERAT URE (°C)
V
IN
= 12V
V
OUT
= 26V
I
OUT
= 0.36A
V
IN
= 12V
V
OUT
= 36V
I
SW
= 1.3A
-40
-20
0
20
40
60
80
100 120
T EM PERAT URE (°C)
Efficiency
v s. Output Current
96
94
92
EFFICIENCY (%)
90
88
86
84
82
80
0
0.5
1
1.5
OUT PUT CURRENT (A)
V
OUT
= 25V
10V
EFFICIENCY (%)
96
Efficiency
v s. Output Current
98
16V
14V
94
92
Efficiency
v s. Output Current
96
94
EFFICIENCY (%)
92
90
88
86
84
18V
20V
12V
8V
90
88
86
84
82
80
0
0.5
1
1.5
OUT PUT CURRENT (A)
V
OUT
= 25V
82
80
0
0.5
1
V
OUT
= 25V
1.5
OUT PUT CURRENT (A)
January 2010
5
M9999-011510-A
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