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A New Approach to Circuit Breaker Design Using Silicon Carbide Switches - Nov 21
Mechanical circuit breakers can be low cost with minimal losses, but they operate slowly and wear out. Solid state versions overcome the problems and are becoming increasing viable as replacements at...
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Power Electronics Europe News
 
Synchronous step-down DC/DC converter allows independent operation

The integrated, lossless PowerPath circuitry supports seamless operation from two separate input power sources, says Linear Technology. The power stage topology enables operation from either of two independent power sources. Seamless, internally controlled transitions between inputs ensure a stable output voltage during hot-plug and power source disconnect events. Internal power switches and synchronous rectification deliver 95% efficiency and are claimed to enable a fast transient response and ensure excellent loop stability while switching at 2MHz.

The current mode topology is internally compensated, eliminating the need for external compensation components for a compact footprint. Burst Mode operation maintains high efficiency at low output currents while keeping peak-to-peak output ripple below 1%. Quiescent current under 2µA in no-load standby conditions are suitable for always-on systems and portable applications. The wide 2.4 to 42V input and 0.818V to VIN output voltage ranges are suited for automotive applications which must regulate through cold-crank, load dump and stop-start scenarios. Other applications include portable industrial/communications test equipment, battery and super-capacitor back-up power systems, automotive power with battery back-up, UPS, and systems powered by unregulated wall adapters or single to multi-cell stacks of most battery chemistries.

Pin-selectable ideal diode-OR and priority input modes with user-programmable under-voltage lock-out thresholds provide full control over the transition between the input power sources. The fast, automatic switchover eliminates the need for hold-up capacitors and minimises disturbances on the output rail, says the company. An active input channel indicator and independent input and output power good signals provide complete feedback of the power system status. Other features include 1µA current in shutdown, internal soft-start and thermal protection.

The thermally enhanced 28-lead TSSOP and 4.0 x 5.0mm QFN packages can be combined with high switching frequency to enable small external inductors and capacitors. E-and I-grade devices both feature an operating junction temperature of -40 to 125°C. The H-grade high reliability version is offered in TSSOP only and operates from -40 to 150°C.

 

 

 



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