Rainbow Electronics MAX16822B - Manual (Page 5)

MAX16822A/MAX16822B
2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
_______________________________________________________________________________________ 5
Typical Operating Characteristics (continued)
(V IN = V DIM = 48V, C VCC = 1µF, R SENSE = 0.62Ω, L = 220µH (connected between IN and CS). Typical values are at T A = +25°C,
unless otherwise noted.)
LX RDSON
vs. TEMPERATURE
MAX16822A toc11
TEMPERATURE ( °C)
LX
RDSON
(Ω
)
110 95 80 65 50 35 20 5 -10 -25
0.5
0.6
0.7
0.8
0.9
1.0
0.4
-40 125
V IN = 6.5V
V IN = 65V
V IN = 48V
I TEMP_I
vs. TEMPERATURE
MAX16822A toc12
I TEMP_
(μ
A)
25.5
26.0
26.5
27.0
27.5
28.0
28.5
29.0
29.5
30.0
25.0
TEMPERATURE ( °C)
110 95 80 65 50 35 20 5 -10 -25 -40 125
V IN = 48V
Pin Description
PIN NAME FUNCTION
1 CS Current-Sense Input. Connect a resistor between IN and CS to program the LED current.
2 IN Positive Supply Voltage Input. Bypass with a 1µF or higher value capacitor to GND.
3 GND Ground
4 PGND Power Ground
5, 6 LX Switching Node
7 DIM
Logic-Level Dimming Input. Drive DIM low to turn off the current regulator. Drive DIM high to
enable the current regulator.
8 TEMP_I
Thermal Foldback Control and Linear Input. Bypass with a 0.01µF capacitor to GND if thermal
foldback or analog dimming is used. See the Thermal Foldback section for more details.
Detailed Description
The MAX16822A/MAX16822B are step-down, constant-
current, high-brightness LED (HB LED) drivers. These
devices operate from a +6.5V to +65V input-voltage
range and deliver up to 350mA of output current. A high-
side current-sense resistor sets the output current and a
dedicated PWM dimming input enables pulsed LED
dimming over a wide range of brightness levels.
A high-side current-sensing scheme and an on-board
current-setting circuitry minimize the number of exter-
nal components while delivering LED current with ±3%
accuracy, using a 1% sense resistor. See Figure 1 for
an internal block diagram.