MAX16812 Datasheet, PDF (1/21 Pages) Maxim Integrated Products – Integrated High-Voltage LED Driver with Analog and PWM Dimming Control

19-0880; Rev 0; 7/07
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
General Description
The MAX16812 is a peak-current-mode LED driver with
an integrated 0.2Ω power MOSFET designed to control
the current in a single string of high-brightness LEDs
(HBLEDs). The MAX16812 can be used in multiple con-
verter topologies such as buck, boost, or buck-boost.
The MAX16812 operates over a 5.5V to 76V wide sup-
ply voltage range.
The MAX16812 features a low-frequency, wide-range
brightness adjustment (100:1), analog and PWM dim-
ming control input, as well as a resistor-programmable
EMI suppression circuitry to control the rise and fall
times of the internal switching MOSFET. A high-side
LED current-sense amplifier and a dimming MOSFET
driver are also included, simplifying the design and
reducing the total component count.
The MAX16812 uses peak-current-mode control,
adjustable slope compensation that allows for addition-
al design flexibility. The device has two current regula-
tion loops. The first loop controls the internal switching
MOSFET peak current, while the second current regula-
tion loop controls the LED current. Switching frequency
can be adjusted from 125kHz to 500kHz.
Additional features include adjustable UVLO, soft-start,
external enable/disable input, thermal shutdown, a
1.238V 1% accurate buffered reference, and an on-
chip oscillator. An internal 5.2V linear regulator supplies
up to 20mA to power external devices.
The MAX16812 is available in a thermally enhanced
5mm x 5mm, 28-pin TQFN-EP package and is specified
over the automotive -40°C to +125°C temperature range.
Applications
Automotive Lighting:
DRL, Fog Lights
Rear Combination Lights
Front and Rear Signal Lights
Interior Lighting
Warning and Emergency Lighting
Architectural and Industrial Lighting
Features
♦ Integrated 76V, 0.2Ω (typ) Power MOSFET
♦ 5.5V to 76V Wide Input Range
♦ Adjustable LED Current with 5% Accuracy
♦ Floating Differential LED Current-Sense Amplifier
♦ Floating Dimming N-Channel MOSFET Driver
♦ PWM LED Dimming with:
PWM Control Signal
Analog Control Signal
Chopped V_IN Input
♦ Peak-Current-Mode Control
♦ 125kHz to 500kHz Adjustable Switching Frequency
♦ Adjustable UVLO and Soft-Start
♦ Output Overvoltage Protection
♦ 5µs LED Current Rise/Fall Times During Dimming
Minimize EMI
♦ Overtemperature and Short-Circuit Protection
Ordering Information
PART
TEMP RANGE ^PIN-
PACKAGE
PKG
CODE
MAX16812ATI+ -40°C to +125°C 28 TQFN-EP* T2855-8
+Denotes a lead-free package.
*EP = Exposed pad.
Simplified Diagram
CH_REG
RCS
VIN
LV
IN
CIN
EN
RT
RT
RTGRM
L_REG
CTGRM
TGRM
DIM
MAX16812
DOUT
VOUT
COUT
RSRC
SRC
GT
DRV
SLP
CSLP
COMP
Typical Application Circuit and Pin Configuration appear at
end of data sheet.
ROV1
VOUT
ROV2
RCOMP1
BUCK-BOOST CONFIGURATION
CCOMP1
RCOMP2
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