MAX16803_09 Datasheet, PDF (7/11 Pages) Maxim Integrated Products – High-Voltage, 350mA, High-Brightness LED Driver with PWM Dimming and 5V Regulator

High-Voltage, 350mA, High-Brightness LED
Driver with PWM Dimming and 5V Regulator
Input-Voltage Considerations
For proper operation, the minimum input voltage must
always be:
V_IN(MIN) ≥ V_RSENSE(MAX) + V_FT(MAX) + ∆V_DO(MAX)
where V_FT(MAX) is the total forward voltage of all series
connected LEDs. The minimum operating voltage of the
device is +6.5V. The device operates below +6.5V; how-
ever, output current may not meet the full regulation
specification (see the Typical Operating Characteristics).
Low-Frequency PWM Dimming at the Output
The MAX16803 provides pulsed or chopped current
dimming input (DIM). The other method is to connect
DIM to V5 and EN to IN and pulse EN. Both methods
generate a regulated-amplitude PWM current (variable
duty cycle) that can provide control over the LED
brightness (see Figures 1 and 2).
VDIM
VIN
C1
16 15 14 13
OUT EN N.C. DIM
1 OUT
GND 12
2 IN
3 IN
MAX16803
V5 11
CS- 10
ILED
D1
C2
RSENSE
4 N.C.
CS+ 9
N.C. N.C. N.C. N.C.
5
6
7
8
Figure 1. Dimming with EN Connected to V_IN at a Constant
Voltage and DIM Pulsed
16 15 14 13
OUT EN N.C. DIM
1 OUT
GND 12
ILED
VIN
2 IN
D1
V5 11
C1
3 IN
MAX16803
CS- 10
C2
RSENSE
4 N.C.
CS+ 9
N.C. N.C. N.C. N.C.
5
6
7
8
Figure 2. Dimming with DIM Connected to V5, EN Connected
to V_IN
Paralleling Multiple MAX16803s to Drive
One High-Power LED
For applications that require more than 350mA of LED
current, two or more MAX16803s can be paralleled
(see Figure 3). V_CS- should not exceed 4.1V.
R1
IN
OUT
EN
C1
V5
C2
MAX16803
V5
DIM
CS+
CS-
GND
V5
R2
IN
OUT
EN
C3
V5
C4
MAX16803
V5
DIM
CS+
LEDs
CS-
GND
Figure 3. Paralleling MAX16803s
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