The TPS92410 supports a broad range of input voltages and can be used in linear LED drivers or alongside the company's floating switch in AC-LED or direct-AC implementations.
Texas Instruments (TI) has announced the TPS92410 linear LED driver IC that can supply constant current to high-voltage LED strings. The new IC can be used along with AC/DC or DC/DC converters in conventional LED driver designs, or with a simple rectifier and TI's TPS92411 floating switch IC in AC-LED or direct-AC designs.
The new IC works across an especially wide input-voltage range from 9.5–450 VAC. The output current is set with a resistor. The IC can work with phase-cut dimmers including triac or electronic controls and can also accept an analog input for 0–10V implementations. The product includes under-voltage lockout, over-voltage protections, and thermal foldback to protect LED-based lamps or luminaires from catastrophic failure.
The IC also includes an active on-chip power factor correction circuit. The design enables power factor greater than 0.95 along with line regulation within 3%.
Still, the most significant elements of the new driver align with two key trends in the solid-state lighting (SSL) industry. Increasingly, LED manufacturers are delivering packaged LEDs with multiple emitters in series and relatively high forward voltages. The TPS92410 can support virtually any imaginable LED topology.
The second trend is the broader use of AC-LED driver technology that is also referred to as AC-direct or driverless technology. The technique greatly simplifies the driver electronics, although such designs don’t typically match the efficacy of DC-driven designs and dimming performance, and flicker can be an issue. For more information, we recently published a feature article on various approaches to AC-direct designs. Moreover, a recent free webcast from Seoul Semiconductor details some of the latest advancements in direct-AC technology.
The TI IC combined with the TPS92411 switch IC announced about a year ago addresses several of the issues with direct-AC designs. The floating switch (not connected to ground) allows the driver implementation to utilize capacitors across the LED segments, thereby keeping the LEDs illuminated even when the AC input drops below the forward voltage of a segment. The result is presumably less flicker and smoother dimming.
TI offers an evaluation module that combines the TPS92410 and TPS92411 ICs in a typical design. Indeed, the modules are offered in 110V and 220V versions. Those ICs can easily be combined with TI microcontrollers (MCUs) such as the ultralow-power MSP430F5172 or the ZigBee-based CC2530 for smart-lighting applications.