Power_electronics Features

NewSpace demands low voltage, high current power for performance and longevity - Nov 2022
Matt Renola, Senior Director, Global Business Development – Aerospace & Defense
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Power Electronics Europe News
Synchronous step-down controller reduces circuit size

The controller has low 45ns minimum on-time which enables 24VIN to 3.3VOUT conversions. The company says that switching at a fixed 2MHz avoids critical noise-sensitive frequency bands including AM radio. Synchronous rectification delivers up to 95% efficiency, while Burst Mode operation keeps quiescent current under 50μA in no-load standby conditions. This is particularly suitable for always-on systems.


The controller operates over a 4.0 to 60V input supply range, designed to protect against high voltage transients, continuous operation during automotive cold crank and to cover a range of input sources and battery chemistries. The output voltage can be set from 0.8 to 24V at output currents up to 20A, which is suitable for 12 or 24V automotive, heavy equipment, industrial control, robotics and telecomms applications.


The controller has powerful 1.1Ω on-chip MOSFET gate drivers. Fixed frequency is selectable between 320kHz and 2.25MHz, which can be synchronised to an external clock over the same range. The user can select continuous operation, pulse-skipping or low ripple Burst Mode operation during light loads. Current mode architecture provides easy loop compensation, fast transient response and line regulation. Output current sensing is shed by Measuring the voltage drop across the output inductor (DCR) removes output current sensing for the highest efficiency, claims the company. Current foldback limits MOSFET heat dissipation during overload conditions. Other features include up to 98% duty cycle, an internal LDO that powers the gate drive from the input voltage or EXTVCC, and a power-good output signal.


The controller is available in a 20-lead 3.0 x 4.0mm QFN, thermally enhanced package, which is pin-compatible to the company’s LTC3891. Two operating junction temperature grades are available with extended and industrial versions from -40 to 125°C and a high temp automotive grade version from -40 to 150°C.


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