MAX16822A Просмотр технического описания (PDF) - Maxim Integrated

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MAX16822A

2MHz, High-Brightness LED Drivers with Integrated MOSFET and High-Side Current Sense

Maxim Integrated 

EVALUATION KIT AVAILABLE

MAX16822A/MAX16822B

2MHz, High-Brightness LED

Drivers with Integrated MOSFET

and High-Side Current Sense

General Description

The MAX16822A/MAX16822B step-down constant-cur-

rent high-brightness LED (HB LED) drivers provide a

cost-effective design solution for automotive

interior/exterior lighting, architectural and ambient light-

ing, LED bulbs, and other LED illumination applications.

The MAX16822A/MAX16822B operate from a +6.5V to

+65V input-voltage range and can provide an output

current up to 350mA, if operated up to a temperature of

+125°C, or up to 500mA, if operated up to a tempera-

ture of +105°C. A high-side current-sense resistor

adjusts the output current and a dedicated pulse-width

modulation (PWM) input enables pulsed LED dimming

over a wide range of brightness levels.

These devices are well suited for applications requiring

a wide input-voltage range. The high-side current sens-

ing and an integrated current-setting circuitry minimize

the number of external components while delivering an

average output current with ±3% accuracy. A hysteretic

control method ensures excellent input supply rejection

and fast response during load transients and PWM dim-

ming. The MAX16822A allows 10% current ripple and

the MAX16822B allows 30% current ripple. Both

devices operate up to a switching frequency of 2MHz,

thus allowing the use of small-sized components.

The MAX16822A/MAX16822B offer an analog dimming

feature that reduces the output current by applying an

external DC voltage below the internal 2V threshold volt-

age from TEMP_I to GND. TEMP_I also sources 25µA to

a negative temperature coefficient (NTC) thermistor con-

nected between TEMP_I and GND, thus providing an

analog thermal-foldback feature that reduces the LED

current when the temperature of the LED string exceeds

a specified temperature point.

An additional feature includes thermal-shutdown pro-

tection that turns off the LX driver when the junction

temperature exceeds +165°C.

The MAX16822A/MAX16822B operate over the -40°C to

+125°C automotive temperature range and are available

in an 8-pin SO package.

Applications

Architectural, Industrial, and Ambient Lighting

Automotive RCL, DRL, and Fog Lights

Heads-Up Displays

Indicator and Emergency Lighting

Pin Configuration appears at end of data sheet.

Benefits and Features

• Cost-Effective Solution for Wide Range of LED

Lighting Applications

• 6.5V to 65V Input Voltage Range

• Output Current Up to 500mA

• ±3% LED Current Accuracy

• Selectable Dimming Options: Linear or PWM

• Minimal Component Count Saves Cost and Space

• On-Board 65V, 0.85Ω Power MOSFET

• Resistor-Programmable Constant LED Current

• Integrated High-Side Current Sense with 200mV

Current-Sense Reference

• Hysteretic Control: Up to 2MHz Switching

Frequency

• Protection Features and Wide Operating

Temperature Range Improves Reliability

• Thermal-Foldback Protection Dims LEDs to

Minimize Overheating

• Thermal-Shutdown Protection

• Available in an 8-Pin SO Package

• Operation Over -40°C to +125°C Temperature

Range

Ordering Information

PART

TEMP RANGE PIN-PACKAGE

MAX16822AASA+

-40°C to +125°C 8 SO

MAX16822AASA/V+ -40°C to +125°C 8 SO

MAX16822BASA+

-40°C to +125°C 8 SO

+Denotes a lead(Pb)-free/RoHS-compliant package.

/V denotes an automotive qualified part.

Typical Application Circuit

D1

HB LEDs

VIN

RSENSE

L1

C2

1 CS

TEMP_I 8

2 IN MAX16822A DIM 7

NTC*

ON

OFF

C1

MAX16822B

3 GND

LX 6

4 PGND

LX 5

*OPTIONAL

19-4141; Rev 4; 2/15

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