Analog Devices LT8390 | Demoboard DC2431A

Beschreibung

Demonstration circuit 2431A is a 4-switch synchronousbuck-boost regulator that demonstrates the high powercapability of  the LT®8390. The output is 12V and themaximum output current is 25A for up to 300W powerdelivery. The switching frequency is 150kHz and efficiencycan go higher than 98%.The operating input voltage range of DC2431A is from 9V to36V. The output voltage and EN/UVLO are all programmedby resistor dividers. EN/UVLO is set so the circuit will turnoff when the input voltage falls below 9V and will turn onwhen the input voltage rises above 10V.DC2431A features MOSFETs that complement the 5Vgate drive of the LT8390 to achieve high efficiency. 40VMOSFETs are used on the input side of the four-switchtopology while 25V MOSFETs are used on the output side.Ceramic capacitors are used at both the circuit input andoutput because of their small size and high ripple currentcapability. In addition to ceramic capacitors, there are fourbulk aluminum polymer capacitors on the output. The inputhas four aluminum polymer capacitors.The PCB has large copper planes and extensive vias forexcellent high power thermal performance. There arefour mounting holes on the board for optional heat sinkand fan, which can push the output power of DC2431Aup to 480W. For more details, please consult the factoryfor assistance.The CTRL input is pulled up to the VREF pin through a 0Ωresistor to set the output current limit to its maximum,and an external voltage on CTRL can be used to lower thecurrent limit if the resistor is removed. A capacitor at theSS pin programs soft-start. To improve the EMI performance, the LT8390 has spreadspectrum frequency modulation. With the SYNC/SPRDpin tied to INTVCC, LT8390 starts to spread its switchingfrequency ±15% around the programmed oscillatorfrequency.The PGOOD status flag indicates when output voltage iswithin ±10% of final regulation voltage.The LT8390’s proprietary peak current mode buck-boostarchitecture ensures DC2431A runs either in discontinuousconduction mode (DCM) or pulse-skipping mode (PSM)without reversed inductor current. Both of them enhancethe light load efficiency.The demo circuit is designed to be easily reconfigured tomany other applications, including the example schematicsin the data sheet. Consult the factory for assistance.High power operation, 4-switch buck-boost topology,proprietary peak current mode architecture, fault protectionand full monitoring make the LT8390 attractive forhigh power voltage regulator circuits and also circuits thatrequire output current regulation such as battery chargers.The LT8390EFE is available in a thermally enhanced 28-leadTSSOP package. The LT8390 data sheet must be read inconjunction with this demo manual to properly use ormodify demo circuit DC2431A

Weiterführende Informationen

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