Top

Integrated, 2-Channel, High-Brightness LED Driver with High-Voltage Boost and SEPIC Controller

Industry's Only 2-String HB LED Driver for Automotive Applications Provides a Highly Integrated, Cost-Effective Solution

Product Details

The MAX16838 is a dual-channel LED driver that integrates both the DC-DC switching boost regulator and two 150mA current sinks. A current-mode switching DC-DC controller provides the necessary voltage to both strings of HB LEDs. The MAX16838 accepts a wide 4.75V to 40V input voltage range and directly withstands automotive load-dump events. For a 5V ±10% input voltage, connect VIN to VCC. The wide input range allows powering HB LEDs for small-to-medium-sized LCD displays in automotive and display backlight applications.

An internal current-mode switching DC-DC controller supports the boost or SEPIC topologies and operates in an adjustable frequency range between 200kHz and 2MHz. The current-mode control provides fast response and simplifies loop compensation. The MAX16838 also features an adaptive output-voltage adjustment scheme that minimizes the power dissipation in the LED current sink paths. The MAX16838 can be combined with the MAX15054 to achieve a buck-boost LED driver with two integrated current sinks.

The channel current is adjustable from 20mA to 150mA using an external resistor. The external resistor sets both channel currents to the same value. The device allows connecting both strings in parallel to achieve a maximum current of 300mA in a single channel. The MAX16838 also features pulsed dimming control with minimum pulse widths as low as 1µs, on both channels through a logic input (DIM).

The MAX16838 includes an output overvoltage protection, open LED, shorted LED detection, and overtemperature protection. The device operates over the -40°C to +125°C automotive temperature range. The MAX16838 is available in the 20-pin TSSOP and 4mm x 4mm, 20-pin TQFN packages.

Key Features

  • Integrated, 2-Channel, 20mA to 150mA Linear LED Current Sinks
  • Boost or SEPIC Power Topologies for Maximum Flexibility
  • Adaptive Voltage Optimization to Minimize Power Dissipation in Linear Current Sinks
  • 4.75V to 40V or 5V ±10% Input Operating Voltage Range
  • 5000:1 PWM Dimming at 200Hz
  • Open-Drain Fault Indicator Output
  • LED Open/Short Detection and Protection
  • Output Overvoltage and Overtemperature Protection
  • Programmable LED Current Foldback at Lower Input Voltages
  • 200kHz to 2MHz Resistor Programmable Switching Frequency with External Synchronization
  • Current-Mode Control Switching Stage with Internal Slope Compensation
  • Enable Input
  • Thermally Enhanced, 20-Pin TQFN (4mm x 4mm) and 20-Pin TSSOP Packages

Applications/Uses

  • Automotive Display Backlights
  • Automotive Lighting Applications
  • LCD Display Backlights
Parametric specs for LED Drivers
VIN (V) (min) 4.55
VIN (V) (max) 40
Max. No. of LEDs 22
# LED Channels 2
Regulation Topology Inductor Based
LED Configuration Series-Parallel
ILED per Channel (A) (max) 0.15
PWM Dimming Freq. (kHz) (max) 20
Dimming Ratio (max) 5000
Dimming Control PWM
POUT (W) 10
ICC (mA) (max) 5
LED String Volt. (V) (max) 40
Switching Frequency (kHz) 2000
Package/Pins TQFN/20
TSSOP/20
Budgetary
Price (See Notes)
$2.35 @1k
View More

Simplified Block Diagram

MAX16838: Simplified Functional Diagram MAX16838: Simplified Functional Diagram Zoom icon

Technical Docs

Design & Development

Click any title below to view the detail page where available.

Description

The MAX16838 evaluation kit (EV kit) demonstrates the MAX16838 high-brightness LED (HB LED) driver, integrating a step-up DC-DC preregulator followed by two channels of linear current sinks. The step-up preregulator switches at 500kHz and operates as a current-mode-controlled regulator capable of providing up to 300mA for the linear circuits. Each channel is capable of operating up to 33V and provides up to 150mA. The channels are configurable for 100mA or 150mA HB LED output current. The MAX16838 IC is available in a 20-pin TQFN package with an exposed pad for enhanced thermal power dissipation.

The MAX16838 EV kit operates from a DC supply voltage of 7V up to the HB LED string-forward voltage. The EV kit can withstand a 40V load-dump condition. The EV kit also demonstrates the MAX16838 features, such as adaptive voltage optimization, undervoltage lockout (UVLO), overvoltage protection (OVP), cycle-by-cycle current limit, thermal shutdown, and digital PWM dimming operation using a digital PWM input signal to control the brightness of the HB LEDs.

View Details

Features

  • Input Voltage from 7V Up to HB LED Forward Voltage
  • Demonstrates Overvoltage Protection (35.6V)
  • HB LED String Output Currents Configurable for 100mA or 150mA
  • Demonstrates UVLO (6.4V)
  • Demonstrates Cycle-by-Cycle Current Limit and Thermal Shutdown Features
  • Demonstrates Adaptive Output-Voltage Optimization
  • Configurable LED Current Foldback (VIN < 6.5V)
  • Proven PCB and Thermal Design
  • Fully Assembled and Tested

/en/design/design-tools/ee-sim.html?

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal

Parameters

Parametric specs for LED Drivers
VIN (V) (min) 4.55
VIN (V) (max) 40
Max. No. of LEDs 22
# LED Channels 2
Regulation Topology Inductor Based
LED Configuration Series-Parallel
ILED per Channel (A) (max) 0.15
PWM Dimming Freq. (kHz) (max) 20
Dimming Ratio (max) 5000
Dimming Control PWM
POUT (W) 10
ICC (mA) (max) 5
LED String Volt. (V) (max) 40
Switching Frequency (kHz) 2000
Package/Pins TQFN/20
TSSOP/20
Budgetary
Price (See Notes)
$2.35 @1k

Key Features

  • Integrated, 2-Channel, 20mA to 150mA Linear LED Current Sinks
  • Boost or SEPIC Power Topologies for Maximum Flexibility
  • Adaptive Voltage Optimization to Minimize Power Dissipation in Linear Current Sinks
  • 4.75V to 40V or 5V ±10% Input Operating Voltage Range
  • 5000:1 PWM Dimming at 200Hz
  • Open-Drain Fault Indicator Output
  • LED Open/Short Detection and Protection
  • Output Overvoltage and Overtemperature Protection
  • Programmable LED Current Foldback at Lower Input Voltages
  • 200kHz to 2MHz Resistor Programmable Switching Frequency with External Synchronization
  • Current-Mode Control Switching Stage with Internal Slope Compensation
  • Enable Input
  • Thermally Enhanced, 20-Pin TQFN (4mm x 4mm) and 20-Pin TSSOP Packages

Applications/Uses

  • Automotive Display Backlights
  • Automotive Lighting Applications
  • LCD Display Backlights

Description

The MAX16838 is a dual-channel LED driver that integrates both the DC-DC switching boost regulator and two 150mA current sinks. A current-mode switching DC-DC controller provides the necessary voltage to both strings of HB LEDs. The MAX16838 accepts a wide 4.75V to 40V input voltage range and directly withstands automotive load-dump events. For a 5V ±10% input voltage, connect VIN to VCC. The wide input range allows powering HB LEDs for small-to-medium-sized LCD displays in automotive and display backlight applications.

An internal current-mode switching DC-DC controller supports the boost or SEPIC topologies and operates in an adjustable frequency range between 200kHz and 2MHz. The current-mode control provides fast response and simplifies loop compensation. The MAX16838 also features an adaptive output-voltage adjustment scheme that minimizes the power dissipation in the LED current sink paths. The MAX16838 can be combined with the MAX15054 to achieve a buck-boost LED driver with two integrated current sinks.

The channel current is adjustable from 20mA to 150mA using an external resistor. The external resistor sets both channel currents to the same value. The device allows connecting both strings in parallel to achieve a maximum current of 300mA in a single channel. The MAX16838 also features pulsed dimming control with minimum pulse widths as low as 1µs, on both channels through a logic input (DIM).

The MAX16838 includes an output overvoltage protection, open LED, shorted LED detection, and overtemperature protection. The device operates over the -40°C to +125°C automotive temperature range. The MAX16838 is available in the 20-pin TSSOP and 4mm x 4mm, 20-pin TQFN packages.

Simplified Block Diagram

MAX16838: Simplified Functional Diagram MAX16838: Simplified Functional Diagram Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal