MIC4812
High Current 6 Channel Linear WLED
Driver with DAM™ and Ultra Fast
PWM™ Control
General Description
Features
The MIC4812 is a high efficiency linear White LED
•
High Efficiency (no Voltage Boost losses)
(WLED) driver designed to drive up to six high current
•
Ultra Fast PWM™ control (200Hz to 500kHz)
WLEDs for signage lighting. The MIC4812 provides the
•
Input voltage range: 3.0V to 5.5V
highest possible efficiency as this architecture has no
•
LED current range up to 100mA per channel
switching losses present in traditional charge pumps or
•
Programmable LED current with external resistor
inductive boost circuits. The MIC4812 provides six linear
drivers which maintain constant current for up to six
•
Dropout of 190mV at 100mA
WLEDs. It features a typical dropout of 190mV at 100mA.
•
Matching better than ±1% (typical)
The MIC4812 features Dynamic Average Matching™
•
Current Accuracy better than ±1% (typical)
(DAM™) which is specifically designed to provide optimum
•
Maintains proper regulation regardless of how many
matching across all WLEDs. The high accuracy (±1%
channels are utilized
typical) current regulated WLED channels ensure uniform
•
10-pin MSOP with ePad package
display illumination under all conditions. The brightness is
controlled through an Ultra Fast PWM™ interface
Applications
operating down to less than 1% duty cycle.
The MIC4812 is available in an 10-pin MSOP ePad
•
Billboard displays
package with a junction temperature range of -40°C to
•
Marquee displays
+125°C.
•
Instrument displays
Datasheets and support documentation can be found on
•
LCD display modules
Micrel’s web site at: www.micrel.com.
____________________________________________________________________________________________________________
Typical Application
High Current Lighting (Six WLEDs)
Ultra Fast PWM, DAM and Dynamic Average Matching are trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 •
http://www.micrel.com
April 2011
M9999-041911-B
Micrel Inc.
MIC4812
Ordering Information
Part Number
MIC4812YMME
Mark Code
4812
Junction Temperature Range
–40°C to +125°C
Package
10-Pin ePad MSOP
Pin Configuration
10-Pin ePad MSOP (MME)
(Top View)
Pin Description
Pin Number
1
2
3
4
5
6
7
8
9
10
ePad
Pin Name
VIN
EN
RSET
GND
D6
D5
D4
D3
D2
D1
HS PAD
Pin Function
Voltage Input. Connect at least 2.2µF ceramic capacitor between VIN and GND.
Enable LED drivers. This pin can be used as a PWM input for dimming of WLEDs. Do not leave
floating.
An internal 1.27V reference sets the nominal maximum WLED current. Example, apply a 8.25kΩ
resistor between RSET and GND to set LED current to 100mA at 100% duty cycle.
Ground.
LED6 driver input. Connect LED anode to VIN and cathode to this pin.
LED5 driver input. Connect LED anode to VIN and cathode to this pin.
LED4 driver input. Connect LED anode to VIN and cathode to this pin.
LED3 driver input. Connect LED anode to VIN and cathode to this pin.
LED2 driver input. Connect LED anode to VIN and cathode to this pin.
LED1 driver input. Connect LED anode to VIN and cathode to this pin.
Heat sink pad. Not internally connected. Connect to ground.
April 2011
2
M9999-041419-B
Micrel Inc.
MIC4812
Absolute Maximum Ratings
(1)
Main Input Voltage (V
IN
) .................................. –0.3V to +6V
Enable Input Voltage (V
EN
).............................. –0.3V to +6V
LED Driver Voltage (V
D1-D6
) ............................ –0.3V to +6V
Power Dissipation .....................................Internally Limited
Lead Temperature (soldering, 10sec.)....................... 260°C
Storage Temperature (T
s
) .........................–65°C to +150°C
ESD Rating
(3)
............................................................... 1.5kV
Operating Ratings
(2)
Supply Voltage (V
IN
)..................................... +3.0V to +5.5V
Enable Input Voltage (V
EN
) .................................... 0V to V
IN
LED Driver Voltage (V
D1-D6
) ................................... 0V to V
IN
Junction Temperature (T
J
) ........................ –40°C to +125°C
Junction Thermal Resistance
ePad MSOP-10L (θ
JA
) ....................................76.7°C/W
Electrical Characteristics
V
IN
= V
EN
= 5V, R
SET
= 8.25kΩ; V
D1-D6
= 1.2V; T
J
= 25°C,
bold
values indicate –40°C
≤
T
J
≤
125°C; unless noted.
Parameter
Current Accuracy
(4)
Matching
(5)
Drop-out
Ground/Supply Bias Current
Shutdown Current
PWM Dimming
Enable Input Voltage (V
EN
)
Enable Input Current
Current Source Delay
(50% levels)
Current Source Transient Time
(10%-90%)
Stand-by to Shutdown 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, 1.5kΩ in series with 100pF.
4. As determined by average current of all channels in use and all channels loaded.
5. The current through each LED meets the stated limits from the average current of all LEDs.
Conditions
Min
96
Typ
101
1
Max
106
3.6
320
4.2
1
0.2
Units
mA
%
mV
mA
µA
V
V
µA
µs
µs
µs
µs
µs
Where I
LED
= 90% of LED current seen at
V
DROPNOM
= 1.2V, 100% brightness level
V
EN
= 0V
Logic Low
Logic High
V
IH
> 1.2V
Shutdown to on
Standby to on
On to Standby
T
RISE
T
FALL
V
EN
= 0V
10
1.2
190
3.2
0.01
0.01
40
1
0.3
1
0.3
20
1
60
40
ms
April 2011
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M9999-041419-B
Micrel Inc.
MIC4812
Typical Characteristics
100
AVERAGE CURRENT (mA)
90
80
Average Current
vs. Duty Cycle
1000
Single Channel Current
vs. R
SET
DROPOUT VOLTAGE (mV)
900
800
700
600
500
400
300
200
100
0
0
Single Channel Dropout
vs. LED Current
CURRENT (mA)
70
60
50
40
30
20
10
0
0
20
40
60
80
100
DUTY CYCLE (% )
100
10
1
1
10
100
1000
RSET (kΩ)
100
200
300
400
500
LED CURRENT (mA)
Dropout Voltage
vs. Temperature
275
DROPOUT VOLTAGE(mV)
250
225
200
175
R
SET
=
1.8
CURRENT MATCHING (%)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Average Current Matching
vs. Temperature
LED CURRENT (mA)
105
104
103
102
101
100
99
98
97
96
95
-40 -20
LED1
LED4
LED Current
vs. Temperature
LED6
LED2
LED3
LED5
R
SET
= 8.25kΩ
R
SET
= 8.25kΩ
150
-40 -20
0
20 40 60 80 10 12 14
0 0 0
TEMPERATURE (°C)
-40 -20
0
20 40 60 80 100 120 140
0
20 40 60 80 10 12 14
0 0 0
TEMPERATURE (°C)
TEMPERATURE (°C)
104
103
PEAK ILED (mA)
102
101
100
99
LED6
Peak ILED
vs. Input Voltage
LED2
LED4
LED3
LED5
LED1
R
SET
= 8.25kΩ
98
3.0
3.5
4.0
4.5
5.0
5.5
INPUT VOLTAGE(V)
April 2011
4
M9999-041419-B
Micrel Inc.
MIC4812
Functional Characteristics
April 2011
5
M9999-041419-B
Microchip MCU
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