High voltage compact coil-integrated step-down DC-DC converter series

Torex Semiconductor Ltd. has designed the XCL247/XCL248 Series, compact general-purpose 'micro DC-DC' converters with integrated inductors and high-voltage capabilities. Developed for space-saving and high efficiency under light loads, these converters are outstanding for various applications, including industrial and consumer use.

The series' most notable feature is its high-voltage capability of 36V while attaining ultra-space-saving. Also, with a low quiescent current of just 11µA, the series delivers high efficiency across load conditions – 86% at VIN = 12V, VOUT = 5V, IOUT = 1mA, and 88% at IOUT = 300mA. Using its compact size and high efficiency, the series can easily replace traditional, larger high-voltage LDO regulators, helping to resolve heat generation issues.

The XCL247/XCL248 supports input voltages up to 36V and is compatible with 12V and 24V power supplies widely used in industrial equipment. It provides an output current of 600mA (sufficient for communication modules, sensors, etc.) and operates across a -40C to 105C temperature range. Its coil-integrated design minimises PCB wiring patterns, drastically lowering noise radiation from current loops. Also, the integrated coil eradicates the necessity for external coil selection, streamlining component sourcing, evaluation, and registration during development.

Unlike most medium and high-voltage DC-DC converters that use N-channel driver FETs, the XCL247/XCL248 series adopts P-channel driver FETs. This allows for 100% duty operation, allowing direct pass-through of the input voltage when it falls below the output voltage setting. This feature ensures stable operation even when the input-output voltage difference is small. Further, using the Power Good function, which indicates when the output voltage has sufficiently ramped up, along with the soft-start function during startup, it is feasible to manage power sequencing for downstream loads, a common necessity in industrial equipment.

The XCL247 series uses a fixed PWM control method for stable operation with consistently low ripple voltage, while the XCL248 series employs automatic PWM/PFM switching control to maintain high efficiency across all load conditions. This enables users to select the most suitable control method based on their specific application needs.

The package adopts the compact and thermally efficient Cool Post Type DFN3030-10B (3mm x 3mm x 1.7mm). Despite being a high-voltage and compact product, its structure permits heat to dissipate through the PCB, allowing usage with decreased heat generation.