A Dual Channel DC/DC LED Driver for the Next Generation of Intelligent Lighting

Lumissil is well known for its wide range of LED drivers. New to the family is another product that will provide customers with a competitive advantage with their PCBA design.

EVOLUTION THAT IS TRANSFORMING

The pressures from end customers to reduce costs is never ending. As lighting systems push toward higher efficiency, smarter controls, and multi function integration, designers need LED drivers that can keep pace with the performance and cost goals. The Lumissil IS32LT3962 answers that challenge with a dual channel synchronous DC DC LED driver engineered for automotive, industrial, and architectural applications.

WHAT IS THE IS32LT3962?

The IS32LT3962 integrates two fully independent LED driver channels, each capable of precise current regulation and high efficiency operation. For example, a high beam and low beam headlight function. This allows engineers to consolidate multiple lighting functions into a single IC, reducing system cost, simplifying layout of LDMs (Light Drive Modules) and MLDs (Multi-purpose LED Drivers). Lumissil products also enable advanced lighting behaviors such as multi zone dimming, color mixing, adaptive brightness control and ADB (adaptive beam control).

KEY FEATURES

There are many key features of the IS32LT3962. The dual independent DC-DC LED driver channels offer a wide input voltage range of 4.5 to 80V to accommodate automotive and industrial systems. Its high-efficiency synchronous multi-topology design supports boost, buck-boost, SEPIC and buck use cases. Dimming can be managed by analog internally PWM (Pulse Width Modulation) or externally PWM with excellent fade by low duty cycles. Since the driver is dual channel, there are two standalone brightness outputs via the internal PWM dimming from the integrated PWM generator that has an adjustable frequency of 100Hz~1kHz and 5%~100% adjustable duty cycle. Thermals are managed by LED over temperature current roll-off with externally programmable input undervoltage-lockout all at ±2.8% output current accuracy over a -40°C ~ +150°C temperature range that meets AEC-Q100 Grade 1 for automotive applications. The operating frequency is adjustable from 100kHz~1MHz with an input low-voltage output current reduction function.  Lumissil EMI reduction capabilities are managed by the built-in spread spectrum feature that lowers the EMI load floor. Feedback fault protection with reporting and VCC undervoltage lockout (not reported) are included as desired by many customers. The output overvoltage protection is programmable and has output short circuit protection and RT pin short protection. The IS32LT3962 has VDD pin short protection and undervoltage lockout (not reported). All of what you would expect from Lumissil.

KEY ADVANTAGES

The Lumissil IS32LT3962 offers many advantages over the competition. For example, better output current accuracy and high voltage input up to 80V, which can support a larger number of LED lights or 24V battery systems. There are two analog dimming pins for each channel that can simultaneously realize LED binning capability and LED over-temperature current roll-off. With the internal PWM dimming functions adjustable frequency, you can meet the diverse needs of your customers. The input low-voltage output current reduction function will meet your customer‘s demand for reducing input current when the input voltage is low. This is critically important with the need to reduce stand-by currents in today’s EV and Hybrid vehicles.

LAYOUT OF THE DRIVER

Figure 1: Application Diagram

APPLICATION BENEFITS

The IS32LT3962’s dual channel design enables engineers to power two independent LED strings from a single device. Each channel features its own current regulation loop that allows for independent brightness control, Multi color or multi zone lighting. This driver reduces redundant safety critical lighting paths and consolidates two drivers into one IC. This makes the IS32LT3962 ideal for applications such as automotive high beam / low beam, DRL / turn signals, and position lamps, industrial machine lighting, architectural accent lighting and even emergency and safety lighting.

HIGH EFFICIENCY FOR COOLER, LONGER-LASTING SYSTEMS

When using a synchronous buck topology, the IS32LT3962 achieves high conversion efficiency across a wide load range. This reduces heat generation, which is a critical factor in sealed or compact lighting enclosures. Below is a block diagram showing the driver being used for two functions. There is also an image of the demo board Lumissil created. This is a reference design that can be shared to aid in your development. The Lumissil team is always available to help.

Figure 2: IS32LT3962 Boost+Buck-boost Demo

• IS32LT3962 is configured as constant current LED driver mode.

• 1pcs IS32LT3962 can replace 2pcs IS32LT3958 that saves PCB space and cost

MODERN LIGHTING EFFECTS

The IS32LT3962 supports PWM dimming for the demands of modern lighting systems. Managing fast, flicker free control, the analog dimming allows for smooth transitions in a wide dynamic range. Some examples are smooth fades, rapid strobe patterns, sensor driven adaptive brightness, and multi channel synchronized effects.

PROTECTION FOR HARSH ENVIRONMENTS

Lumissil designed the IS32LT3962 for the harsh environments that our customers face. LED open/short detection, over temperature protection, cycle by cycle current limiting and under voltage lockout were all built into this drivers DNA. These protections ensure long term reliability in automotive and industrial environments where voltage spikes, thermal stress, and load faults are common.

REAL WORLD APPLICATIONS

Automotive

  • DRLs

  • Turn indicators

  • Tail lamps

  • Adaptive headlights

  • Multi function light bars

Industrial

  • Machine vision lighting

  • Inspection lamps

  • Warehouse illumination

  • Emergency signage

Architectural

  • Accent lighting

  • Wall washers

  • Color tunable fixtures

Figure 3: Example of an LDM (Light Drive Module) using the Lumissil Dual-Channel DC-DC

SPREAD SPECTRUM TECHNOLOGY

Lumissil is always looking for the challenges our customers face. Spread spectrum technology is designed into many of our drivers. It is designed to disperse the energy concentrated at the switching frequency, thereby reducing EMI noise at the switching frequency and harmonics.

Figure 4: Scope Image showing the effectiveness of the Spread Spectrum Technology.

WHY THE IS32LT3962 STANDS OUT

The IS32LT3962 is more than a dual channel LED driver, it is a platform for building smarter, more efficient, and more reliable lighting systems. Its combination of high efficiency, robust protection, and flexible dimming makes it a strong fit for next generation designs across multiple industries. Below you can see how the IS32LT3962 compares to Infineon and Elmos dual channel drivers. Higher voltage, better temperature ranges, increased frequency, lower shutdown current and better PWM control all stand out and will prove to make your designs more robust.

CONCLUSION

Lumissil’s IS32LT3962 delivers the dual channel LED driver solution our customers need today. We are here to support your designs and can help study your schematic thermals before you build your first PCBA to give you confidence in testing and validation. This is support and dedication the Lumissil prides itself on. Thank you for your continued business.