MAX16819 [MAXIM]
2MHz High-Brightness LED Drivers with High-Side Current Sense and 5000:1 Dimming; 2MHz，高亮度LED驱动器，具有高边电流检测和5000：1的调光
| 型号： | MAX16819 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | 2MHz High-Brightness LED Drivers with High-Side Current Sense and 5000:1 Dimming |
| 文件： | 总10页 (文件大小：216K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-0706; Rev 0; 12/06
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
9/MAX16820
General Description
Features
♦ High-Side Current Sense
♦ Dedicated Dimming Control Input
♦ 20kHz Maximum Dimming Efficiency
The MAX16819/MAX16820, step-down constant-current
high-brightness LED (HB LED) drivers provide a cost-
effective solution for automotive interior/exterior lighting,
architectural and ambient lighting, LED bulbs such as
MR16 and other LED illumination applications.
♦ Hysteretic Control: No Compensation
♦ Up to 2MHz Switching Frequency
♦ ±±5 ꢀED Current ꢁccuracy
The MAX16819/MAX16820 operate from a 4.5V to 28V
input voltage range and feature a 5V/10mA on-board
regulator. A high-side current-sense resistor adjusts the
output current and a dedicated PWM input (DIM)
enables a wide range of pulsed dimming.
♦ ꢁdjustable Constant ꢀED Current
♦ 4.±V to 28V Input Voltage Range
♦ Over 2±W Output Power
The MAX16819/MAX16820 are well suited for applica-
tions requiring a wide input voltage range. The high-side
current-sensing and an integrated current-setting circuit-
ry minimize the number of external components while
delivering an LED current with 5ꢀ accuracy. A hys-
teretic control algorithm ensures excellent input-supply
rejection and fast response during load transients and
PWM dimming. The MAX16819 features a 30ꢀ inductor
current ripple and the MAX16820 features a 10ꢀ current
ripple. These devices operate up to 2MHz switching fre-
quency, thus allowing for small component size.
♦ ±V, 10mꢁ On-Board Regulator
♦ -40°C to +12±°C Operating Temperature Range
Ordering Information
TOP
MꢁRK
PꢁRT
PIN-PꢁCKꢁGE PKG CODE
MꢁX16819ATT+T 6 TDFN–EP*
MꢁX16820ATT+T 6 TDFN-EP*
T633-2
T633-2
+ATB
+ATC
The MAX16819/MAX16820 operate over the -40°C to
+125°C automotive temperature range and are avail-
able in 3mm x 3mm x 0.8mm, 6-pin TDFN packages.
Note: All devices are specified over the -40°C to +125°C oper-
ating temperature range.
+Denotes lead-free package.
*EP = Exposed paddle.
Applications
Architectural, Industrial, and Ambient Lighting
Automotive RCL, DRL, and Fog Lights
MR16 and Other LED Bulbs
Typical Operating Circuit
Indicators and Emergency Lighting
V
IN
R
L
SENSE
Pin Configuration
C
IN
TOP VIEW
6
5
4
C
VCC
MAX16819
MAX16820
IN
V
CC
MAX16819
MAX16820
CSN
DRV
GND
+
1
2
3
DIM
TDFN
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
ꢁBSOꢀUTE MꢁXIMUM RꢁTINGS
IN, CSN, DIM to GND.............................................-0.3V to +30V
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Pin-to-Pin ESD Ratings (HB Model).....................................2.5kV
*As per JEDEC51 Standard (Single-Layer Board).
V
, DRV to GND ....................................................-0.3V to +6V
CC
CSN to IN...............................................................-0.3V to +0.3V
Maximum Current into Any Pin
(except IN, V , and DRV)............................................ 20mA
CC
Continuous Power Dissipation (T = +70°C)
A
6-Pin TDFN (derate 18.17mW/oC* above +70°C).......1454mW
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
EꢀECTRICꢁꢀ CHꢁRꢁCTERISTICS
(V = 12V, V
= V , C
= 1µF, R
= 0.5Ω, T = T = -40°C to +125°C, unless otherwise noted. Typical values are at
IN
DIM
IN
VCC
SENSE
A
J
T
A
= +25°C.) (Note 1)
PꢁRꢁMETER
Input Voltage Range
SYMBOꢀ
CONDITIONS
MIN
TYP
MꢁX
UNITS
V
4.5
28.0
V
IN
Maximum Current Regulator
Switching Frequency
f
2
MHz
SW
9/MAX16820
Ground Current
Supply Current
I
DRV open
1.5
mA
µA
GND
I
V
< 0.6V
425
IN
DIM
V
V
= V
= V
- 0.5V
CC
, V rising from 4V until
DIM IN
IN
CSN
4.7
0.5
5.0
4.5
> V
DRV
Undervoltage Lockout
UVLO
V
V
V
V
= V
= V
, V falling from 6V,
DIM IN
IN
CSN
< 0.5V
DRV
Undervoltage Lockout Hysteresis
SENSE COMPꢁRꢁTOR
(V - V
0.5V (MAX16820)
) rising from 0V until V
<
IN
CSN
DRV
195
213
176
158
210
230
190
170
82
225
246
204
182
Sense Voltage Threshold High
Sense Voltage Threshold Low
V
mV
mV
SNSHI
(V - V ) rising from 0V until V
<
IN
CSN
DRV
0.5V (MAX16819)
(V - V ) falling from 0.26V until V
>
>
IN
CSN
DRV
DRV
(V
CC
- 0.5V) (MAX16820)
V
SNSLO
(V - V
) falling from 0.26V until V
IN
CSN
(V
CC
- 0.5V) (MAX16819)
Propagation Delay to Output
High
Falling edge of (V - V
0V to DRV high, C
) from 0.26V to
CSN
IN
t
ns
ns
DPDH
= 1nF
DRV
Rising edge of (V - V
) from 0V to
CSN
= 1nF
IN
Propagation Delay to Output Low
Current-Sense Input Current
t
82
DPDL
0.26V to DRV low, C
DRV
I
(V - V ) = 200mV
IN CSN
1
µA
mV
mV
CSN
MAX16819
MAX16820
56
17
70
35
Current-Sense Threshold
Hysteresis
CS
HYS
2
_______________________________________________________________________________________
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
9/MAX16820
EꢀECTRICꢁꢀ CHꢁRꢁCTERISTICS (continued)
(V = 12V, V
IN
= V , C
= 1µF, R
= 0.5Ω, T = T = -40°C to +125°C, unless otherwise noted. Typical values are at
SENSE A J
DIM
IN
VCC
T
A
= +25°C.) (Note 1)
PꢁRꢁMETER
GꢁTE DRIVER
SYMBOꢀ
CONDITIONS
MIN
TYP
MꢁX
UNITS
Gate Driver Source Current
Gate Driver Sink Current
Gate Driver Output-Voltage High
Gate Driver Output-Voltage Low
DIM INPUT
V
V
= V , V
= 0.5 x V
0.5
1
A
A
V
V
CSN
CSN
IN DRV
CC
= V - 250mV, V
= 0.5 x V
CC
IN
DRV
V
I
I
= 10mA
= -10mA
V
- 0.5
CC
OH
DRV
DRV
V
0.5
20
OL
Maximum DIM Frequency
f
kHz
V
DIM
V
(V
= V , increase DIM until V
>
DRV
CSN
IN
DIM Input-Voltage High
V
2.8
IH
- 0.5V)
CC
V
V
= V , decrease DIM until
IN
< 0.5V
CSN
DRV
DIM Input-Voltage Low
DIM Hysteresis
V
0.6
V
IL
DIM
200
100
mV
ns
HYS
DIM rising edge to V
C
= 0.5 x V
,
CC
DRV
DIM Turn-On Time
t
DIMON
= 1nF
DRV
DIM falling edge to V
= 0.5 x V
,
CC
DRV
DIM Turn-Off Time
t
100
ns
DIMOFF
C
= 1nF
DRV
DIM Input Leakage High
DIM Input Leakage Low
V
V
= V
10
+1
µA
µA
DIM
DIM
IN
= 0V
-1
V
CC
REGUꢀꢁTOR
I
I
I
= 0.1mA to 10mA, V = 5.5V to 28V
4.5
4.0
5.5
5.5
V
VCC
VCC
VCC
IN
Regulator Output Voltage
V
CC
= 0.1mA to 10mA, V = 4.5V to 28V
V
IN
Load Regulation
= 0.1mA to 10mA, V = 12V
4
Ω
IN
Line Regulation
V
V
V
V
V
= 6V to 28V, I
= 10mA
11
mV
dB
mA
mA
µs
IN
IN
IN
IN
CC
VCC
Power-Supply Rejection Ratio
PSRR
= 12V, I
= 5mA, f = 10kHz
IN
-35
45
VCC
= 4.5V, V
= 4.5V, V
= 0V
= 4V
CC
CC
Current Limit
I
LIM
18
Regulator Startup Time
t
= 0 to 4.5V
350
STRAT
Note 1: All devices are 100ꢀ production tested at T = +25°C and +125°C. Limits to -40°C are guaranteed by design.
J
_______________________________________________________________________________________
3
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
Typical Operating Characteristics
(V = V
IN
= 12V, C
= 1µF, R
= 0.5Ω connected between IN and CSN. Typical values at T = +25°C, unless otherwise
DIM
VCC
SENSE
A
noted.)
DRV SWITCHING FREQUENCY
EFFICIENCY vs. V
IN
vs. V
LED CURRENT VARIATION vs. V
IN
IN
100
95
90
85
80
75
70
65
60
1500
1400
1300
1200
1100
1000
900
800
700
600
500
2.0
1.5
1.0
0.5
0
LED 5
L = 47µH
I
LED(NOMINAL)
= 400mA
LED 5
L = 47µH
LED 4
LED 4
LED 3
LED 1
LED 2
LED 3
LED 2
LED 1
-0.5
-1.0
-1.5
-2.0
LED 2
400
300
200
100
0
LED 1
LED 4
LED 3
10
L = 47µH
LED 5
25
5
10
15
20
25
30
4
8
12
16
(V)
20
24
28
5
15
20
30
V
(V)
V
IN
IN
V
(V)
IN
9/MAX16820
SUPPLY CURRENT vs. V
V
CC
vs. V
V
CC
vs. TEMPERATURE
IN
IN
300
250
200
150
100
50
5.5
5.4
5.3
5.2
5.1
5.0
4.9
4.8
4.7
4.6
4.5
5.40
5.39
5.38
5.37
5.36
5.35
5.34
5.33
5.32
5.31
5.30
V
= 24V
IN
V
= 12V
IN
V
= 0V
DIM
I
= 0
LED
V
= 0V
DIM
0
12.5
4.5
8.5
16.5 20.5
(V)
24.5
28.5
5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 27.5
(V)
-40 -25 -10
5
20 35 50 65 80 95 110 125
V
V
TEMPERATURE (°C)
IN
IN
PWM DIMMING AT 200Hz
(10% DUTY CYCLE)
PWM DIMMING AT 200Hz
(90% DUTY CYCLE)
MAX16819 toc07
MAX16819 toc08
V
= 12V, L = 47µH,
IN
V
= 12V, L = 47µH,
IN
1 LED MAX16819
1 LED MAX16819
V
DIM
V
DIM
2V/div
2V/div
0V
0V
I
LED
I
LED
200mA/div
200mA/div
0A
0A
1ms/div
1ms/div
4
_______________________________________________________________________________________
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
9/MAX16820
Typical Operating Characteristics (continued)
(V = V
IN
= 12V, C
= 1µF, R
= 0.5Ω connected between IN and CSN. Typical values at T = +25°C, unless otherwise
SENSE A
DIM
VCC
noted.)
PWM DIMMING AT 200Hz
(1% DUTY CYCLE)
PWM DIMMING EXPANDED
(50% DUTY CYCLE)
PWM DIMMING EXPANDED
(50% DUTY CYCLE)
MAX16819 toc09
MAX16819 toc10
MAX16819 toc11
V
= 12V, L = 47µH,
V
= 24V, L = 33µH,
IN
V = 12V, L = 47µH,
IN
1 LED MAX16819
IN
1 LED MAX16819
4 LEDS MAX16820
V
V
DIM
V
DIM
2V/div
DIM
2V/div
2V/div
0V
0V
0V
I
I
LED
LED
I
LED
200mA/div
200mA/div
200mA/div
0A
0A
0A
10µs/div
1µs/div
4µs/div
PWM DIMMING AT 20kHz
(90% DUTY CYCLE)
PWM DIMMING AT 20kHz
(10% DUTY CYCLE)
I
VARIATION vs. TEMPERATURE
LED
MAX16819 toc13
MAX16819 toc12
2.0
1.5
1.0
0.5
0
V
= 24V, L = 33µH,
V
= 24V, L = 47µH,
IN
IN
I
= 400mA
LED(NOMINAL)
4 LEDS MAX16820
4 LEDS MAX16820
L = 47µH
V
IN
= 24V
V
V
DIM
DIM
2V/div
2V/div
0V
0V
I
LED
-0.5
-1.0
-1.5
-2.0
200mA/div
I
LED
V
IN
= 12V
200mA/div
0A
0A
V
DIM
= 0V
-40 -25 -10
5
20 35 50 65 80 95 110 125
TEMPERATURE (°C)
10µs/div
10µs/div
_______________________________________________________________________________________
±
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
Pin Description
PIN
1
NꢁME
IN
FUNCTION
Positive Supply Voltage Input. Bypass with a 1µF or higher value capacitor to GND.
Current-Sense Input
2
CSN
Logic-Level Dimming Input. Drive DIM low to turn off the current regulator. Drive DIM high to enable
the current regulator.
3
DIM
4
5
6
GND
DRV
Ground
Gate Drive Output. Connect to the gate of an external n-channel MOSFET.
V
Voltage Regulator Output. Connect a 1µF capacitor from V
to GND.
CC
CC
Exposed Paddle. Connect to a large-area ground plane for improved power dissipation. Do not use
as the only ground connection for the device.
EP
—
Functional Diagram
9/MAX16820
REGULATOR
IN
V
CC
-
+
CS
COMPARATOR
CSN
GATE
DRV
DRIVER
1.23V
+
-
BANDGAP
REF
UVLO
COMPARATOR
GND
DIM
BUFFER
DIM
MAX16819
MAX16820
a dedicated PWM dimming input (DIM) allows for a
wide range of independent pulsed dimming.
Detailed Description
The MAX16819/MAX16820 are step-down, constant-
current, high-brightness LED (HB LED) drivers. These
devices operate from a 4.5V to 28V input voltage range
and provide up to 0.5A of source and 1A of sink drive
capability to the gate of an external MOSFET. A high-
side current-sense resistor sets the output current and
The high-side current-sensing scheme and on-board
current-setting circuitry minimize the number of exter-
nal components while delivering LED current with a
5ꢀ accuracy, using a 1ꢀ sense resistor. See the
Functional Diagram.
6
_______________________________________________________________________________________
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
9/MAX16820
For the values of V
Characteristics.
and V
see the Electrical
SNSLO,
Undervoltage Lockout (UVLO)
SNSHI
The MAX16819/MAX16820 include a 4.5V undervoltage
lockout (UVLO) with 500mV hysteresis. When V falls
IN
Current Regulator Operation
below 4.5V, DRV goes low, turning off the external n-chan-
The MAX16819/MAX16820 regulate the LED output
current using an input comparator with hysteresis
(Figure 1). As the current through the inductor ramps
up and the voltage across the sense resistor reaches
the upper threshold, the voltage at DRV goes low, turn-
ing off the external MOSFET. The MOSFET turns on
again when the inductor current ramps down through
the freewheeling diode until the voltage across the
sense resistor equals the lower threshold. Use the fol-
lowing equation to determine the operating frequency:
nel MOSFET. DRV goes high once V is 5V or higher.
IN
5V Regulator
V
CC
is the output of a 5V regulator capable of sourcing
10mA. Bypass V
to GND with a 1µF capacitor.
CC
DIM Input
The MAX16819/MAX16820 allow dimming with a PWM
signal at the DIM input. A logic level below 0.6V at DIM
forces the MAX16819/MAX16820’s DRV output low,
turning off the LED current. To turn the LED current on,
the logic level at DIM must be at least 2.8V.
V
−n× V
×n× V
×R
(
=
)
IN
IN
LED
LED SENSE
f
SW
Applications Information
V
× ∆V×L
Selecting R
to Set the LED Current
SENSE
where n = number of LEDs, V
= forward voltage
LED
The MAX16819/MAX16820 feature a programmable LED
current using a resistor connected between IN and CSN.
Use the following equation to calculate the sense resistor:
drop of one LED, and ∆V = (V
- V
).
SNSLO
SNSHI
For proper component selection, please use the design
tool available at: http://www.maxim-ic.com/MAX16819-
20-Tool.
V
+ V
V
)( )
(
1
2
SNSHI
SNSLO
R
Ω =
( )
SENSE
I
A
( )
LED
HYSTERETIC MODE
1
SW
T
SW
=
f
I
LED
∆I
AVG. LED
CURRENT
t
V
DIM
t
Figure 1. Current Regulator Operation
_______________________________________________________________________________________
7
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
MOSFET Selection
The MAX16819/MAX16820’s gate driver is capable of
sourcing 0.5A and sinking 1A of current. MOSFET selec-
tion is based on the maximum input operating voltage
PCB Layout Guidelines
Careful PCB layout is critical to achieve low switching
losses and stable operation. Use a multilayer board
whenever possible for better noise immunity. Minimize
ground noise by connecting high-current ground
returns, the input bypass-capacitor ground lead, and
the output-filter ground lead to a single point (star
ground configuration). In normal operation, there are
two power loops. One is formed when the MOSFET is
V , output current I
, and operating switching fre-
LED
IN
quency. Choose a MOSFET that has a higher break-
down voltage than the maximum operation voltage, low
R
, and low total charge for better efficiency.
DS(ON)
MOSFET threshold voltage must be adequate if operat-
ed at the low end of the input-voltage operating range.
on and the high current flows through IN—R
—
SENSE
LEDs—Inductor—MOSFET—GND. The other loop is
formed when the MOSFET is off when the high current
Freewheeling Diode Selection
The forward voltage of the freewheeling diode should
be as low as possible for better efficiency. A Schottky
diode is a good choice as long as the breakdown volt-
age is high enough to withstand the maximum operat-
ing voltage.
circulates through R
—LEDs—Inductor—free-
SENSE
wheeling diode. To minimize noise interaction, each
loop area should be as small as possible.
Place R
as close as possible to the input filter
SENSE
and IN. For better noise immunity, a Kelvin connection
is strongly recommended between CSN and R
The forward current rating of the diode must be at least
equal to the maximum LED current.
.
SENSE
Connect the exposed paddle to a large-area ground
plane for improved power dissipation.
LED Current Ripple
The LED current ripple is equal to the inductor current
ripple. In cases when a lower LED current ripple is
needed, a capacitor can be placed across the LED ter-
minals.
9/MAX16820
Chip Information
PROCESS: BiCMOS
8
_______________________________________________________________________________________
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
9/MAX16820
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
PACKAGE OUTLINE, 6,8,10 & 14L,
TDFN, EXPOSED PAD, 3x3x0.80 mm
1
H
21-0137
2
_______________________________________________________________________________________
9
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
PACKAGE VARIATIONS
COMMON DIMENSIONS
MIN. MAX.
SYMBOL
PKG. CODE
T633-1
N
6
D2
1.50±0.10 2.30±0.10 0.95 BSC
1.50±0.10 2.30±0.10
E2
e
JEDEC SPEC
MO229 / WEEA
MO229 / WEEA
MO229 / WEEC
MO229 / WEEC
MO229 / WEEC
b
[(N/2)-1] x e
1.90 REF
1.90 REF
1.95 REF
1.95 REF
1.95 REF
2.00 REF
2.00 REF
2.40 REF
2.40 REF
0.40±0.05
0.40±0.05
0.30±0.05
0.30±0.05
0.30±0.05
A
0.70
2.90
2.90
0.00
0.20
0.80
3.10
3.10
0.05
0.40
T633-2
6
D
E
0.95 BSC
T833-1
8
1.50±0.10 2.30±0.10 0.65 BSC
1.50±0.10 2.30±0.10 0.65 BSC
1.50±0.10 2.30±0.10 0.65 BSC
T833-2
8
A1
L
T833-3
8
T1033-1
T1033-2
T1433-1
T1433-2
10
10
14
14
1.50±0.10 2.30±0.10 0.50 BSC MO229 / WEED-3 0.25±0.05
k
0.25 MIN.
0.20 REF.
1.50±0.10 2.30±0.10
0.25±0.05
0.20±0.05
0.20±0.05
A2
0.50 BSC MO229 / WEED-3
1.70±0.10 2.30±0.10 0.40 BSC
1.70±0.10 2.30±0.10 0.40 BSC
- - - -
- - - -
9/MAX16820
PACKAGE OUTLINE, 6,8,10 & 14L,
TDFN, EXPOSED PAD, 3x3x0.80 mm
2
-DRAWING NOT TO SCALE-
H
21-0137
2
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