– National Semiconductor Korea (CEO: Choi Chung-won) today launched the LM5119, a high-voltage dual-channel, dual-phase, synchronous buck controller utilizing Emulated Current-Mode (ECM) control. The LM5119 allows for the direct regulation of single or dual high-current voltages from high inputs as high as 65V; consequently, compared to alternative solutions requiring two-stage conversion, it reduces PCB footprint by up to 50% and simplifies high-voltage DC-DC conversion. The LM5119 offers a unique combination of high performance, flexibility, and ease of use, making it suitable for demanding telecommunications, automotive, and industrial control applications requiring precise voltage regulation. This expands National's portfolio of high-voltage synchronous buck controllers to handle weighted load currents.
Today, telecommunications, automotive, and industrial control applications must continue to meet stringent PCB space and efficiency requirements while regulating low output voltages from high input voltages that can vary widely and increasing load currents. Conventional methods require a two-stage DC-DC conversion. The first stage regulates an intermediate bus voltage in the 9V–12V range, while the second stage regulates a specific load voltage that can drop to around 1V and demand currents exceeding 20A. Using National’s LM5119 allows for direct regulation of both output voltages from the input, eliminating the intermediate bus conversion stage that can limit efficiency and double the required component count. By employing National’s proprietary ECM control technology, which enables precise regulation of DC output voltage with excellent transient response, the extremely short duty cycles required for high-voltage applications can be accurately controlled. For applications requiring high current output, the two outputs can be connected in parallel via interleaved switching that minimizes input and output capacities, allowing for the supply of up to 40A.

Technical characteristics of the LM5119 buck controller
National's LM5119 features a wide operating voltage range of 5.5V to 65V and supports precise load voltage regulation from 0.8V to up to 90% of the input voltage using a 0.8V, 1.5% reference voltage. The operating frequency can be user-programmed within the range of 50 kHz to 750 kHz and synchronized with an external clock signal. In Diode Emulation Mode (DEM), efficiency can be improved through discontinuous inductor current operation under light load conditions. This