General Description

The MAX20050–MAX20053 are high-brightness LED (HB LED) drivers for automotive exterior lighting applications. Consisting of a fully synchronous step-down converter with integrated MOSFETs, the devices are capable of driving a series string of LEDs at up to 2A, with a minimum number of external components. The MAX20050/MAX20052 utilize internal loop compensation to minimize component count, while the MAX20051/MAX20053/MAX20053D use external compensation for full flexibility.

The wide 4.5V to 65V input supply range supports extreme automotive cold crank and load-dump conditions. A low- and high-switching frequency option (400kHz or 2.1MHz) provides the designer with the flexibility to optimize for solution size or efficiency, while avoiding interference within the AM band. Spread spectrum provides further options for the designer to reduce EMI at the system level. The MAX20050/MAX20051 have an internal switching frequency of 400kHz, while the MAX20052/MAX20053/MAX20053D have an internal switching frequency of 2.1MHz. In addition, the MAX20051B has spread spectrum disabled.

High-side current regulation means only a single connection to the LED string is required; grounding of the string can be done locally. In addition to PWM dimming, the ICs provide analog dimming using the REFI pin. Fullscale current regulation accuracy is ±2.5%, while the accuracy is ±8% at 10% of full-scale over the full temperature range of -40°C to +125°C. A 5V, 10mA LDO output is available for biasing other circuits.

Fault-protection mechanisms include output overload, short-circuit, and device overtemperature protection. The devices are specified for operation over the full -40°C to +125°C temperature range and are available in thermally enhanced 12-pin (3mm x 3mm) TDFN, 14-pin (5mm x4.4mm) TSSOP, and 24-pin TQFN (4mm x 4mm) packages with an exposed pad.

 

Applications

Daytime Running Lamps (DRLs)

Fog Lamps

Clearance Lamps (CLLs)

Corner Lamps (CLs)

Rear Lamps

Head Lamps

Commercial, Industrial, and Architectural Lighting

Driver Monitoring Systems (DMS)

 

Benefits and Features

Automotive Ready: AEC-Q100 Qualified

Fully Synchronous 2A Step-Down Converter with Integrated 0.14Ω (typ) MOSFETs

Wide 4.5V to 65V Input Supply Range

Two Switching Frequency Options: 400kHz and 2.1MHz

Internal Loop Compensation (MAX20050/MAX20052) and External Loop Compensation (MAX20051/MAX20053/MAX20053D) Options

Switching Frequency Synchronized to PWM Dimming Signal

Active-Low Fault (FLT) Indicator

Output Short-Circuit Protection

High-Side Current Regulation Eliminates One Connection to LED String

Spread-Spectrum Mode Alleviates EMI Problems

Low 200mV Full-Scale High-Side Current-Sense Voltage

REFI Pin Adjusts LED Current Down to Zero

PWM Dimming Disconnects Both High- and LowSide MOSFET Drivers

5V, 10mA LDO Output Provides Bias to Other Circuits

Ultra-Low Shutdown Current (5µA, typ)

Output Overload, Short-Circuit, and Overtemperature Protections

12-Pin (3mm x 3mm) TDFN, 14-Pin (5mm x 4.4mm) TSSOP, and 24-pin (4mm x 4mm) TQFN Package Options

 

Detailed Description

The MAX20050–MAX20053 are HB LED drivers for automotive exterior lighting applications. Consisting of a fully synchronous step-down converter with integrated MOSFETs, the devices are capable of driving a series string of LEDs at up to 2A, with a minimum number of external components. The MAX20050/MAX20052 utilize internal loop compensation to minimize component count, while the MAX20051/MAX20053 use external compensation for full flexibility.

The wide 4.5V to 65V input supply range supports extreme automotive cold-crank and load-dump conditions. A low and high-switching frequency option (400kHz or 2.1MHz) provides the designer with the flexibility to optimize for solution size or efficiency, while avoiding interference within the AM band. Spread spectrum provides further options for the designer to reduce EMI at the system level. The MAX20050/MAX20051 have an internal switching frequency of 400kHz, while the MAX20052/MAX20053 have an internal switching frequency of 2.1MHz.

High-side current regulation means only a single connection to the LED string is required; grounding of the string can be done locally. In addition to PWM dimming, the ICs provide analog dimming using the REFI pin. Full-scale current regulation accuracy is ±2.5%, while the accuracy is ±8% at 10% of full scale, over the full temperature range of -40°C to +125°C. A 5V, 10mA LDO output is available for biasing other circuits.

Fault-protection mechanisms include output overload, short-circuit, and device overtemperature protections.