MAX16804ATP+ Maxim Integrated Products, MAX16804ATP+ Datasheet - Page 7

• Manufacturer Part Number: MAX16804ATP+
• Description: LED Drivers IC LED DRIVER HIGH BRIGHT
• Manufacturer: Maxim Integrated Products

Specifications of MAX16804ATP+

• Low Level Output Current: 35 mA
• High Level Output Current: 350 mA
• Operating Supply Voltage: 5.5 V to 40 V
• Maximum Power Dissipation: 2758.6 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: TQFN-20
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The dimming feature can be used for LED brightness
adjustment (see the Simplified Diagrams ) and theater
dimming. If an external PWM signal is used, the theater-
dimming effect can be achieved by varying the PWM
duty cycle. Figure 1 shows a simple circuit that imple-
ments theater dimming with a DC input signal.
The MAX16804 includes a fixed +5V output regulator
that delivers up to 2mA of load current throughout the
6.5V to 40V input voltage range. Connect a 0.1µF com-
pensation capacitor from V5 to ground. Shorting V5 to
ground disables the thermal shutdown. When EN is low,
V5 is off. V5 stays on during PWM dimming.
The MAX16804 enters a thermal-shutdown mode in the
event of overheating. This typically occurs in overload or
short-circuit conditions on the output. If the junction tem-
perature exceeds T
mal-protection circuitry turns off the series pass device.
The MAX16804 recovers from thermal-shutdown mode
once the junction temperature drops by 23°C (typ). The
part therefore protects itself by thermally cycling in the
event of a short-circuit or overload condition.
Figure 1. Theater Dimming
THEATER
DIMMING
SIGNAL
VIN
IN
EN
DIM
_______________________________________________________________________________________
J
= +155°C (typ), the internal ther-
MAX16804
GND
High-Voltage, 350mA LED Driver with
Thermal Protection
OUT
CS+
CS-
Analog and PWM Dimming Control
V5
+5V Regulator
+5V REG
0.1μF
R
LEDs
SENSE
The MAX16804 uses a sense resistor across CS+ and
CS- to set the LED current. The differential sense ampli-
fier connected across R
immunity and low-frequency noise rejection. The LED
current is given by
For proper operation, the minimum input voltage must
always be:
where V
series connected LEDs and ΔV
drop output voltage. The minimum operating voltage of
the device is +5.5V.
Figure 2 shows two-level brightness adjustment using
the MAX16804 with minimum external components. Set
the dimming level with a resistive divider connected to
DIM. See Equation 1 for details.
Figure 2. Two-Level Brightness Operation
STOP
TAIL
V
IN(MIN)
R1
R2
FT(MAX)
D2
D4
≥ V
D3
RSENSE(MAX)
D1
Applications Information
is the maximum forward voltage of all
Programming the LED Current
Input-Voltage Considerations
I
LED
Two Brightness Levels for
IN
EN
DIM
= V
SENSE
SENSE
MAX16804
+ V
GND
FT(MAX)
DO(MAX)
/R
provides ground-loop
TAIL/STOP Lights
SENSE
OUT
CS+
CS-
V5
+ ΔV
is the maximum
DO(MAX) (3)
LEDs
R
SENSE
(2)
7