Four switch buck-boost controller has spread spectrum
Able to regulate output voltage, and input or output current from input voltages above, below and equal to the output voltage. The LT8390 synchronous buck-boost DC/DC controller has been announced by Linear Technology.
The 4.0 to 60V input voltage range and 0 to 60V output range are suitable for voltage regulator, battery and supercap charger applications in automotive, industrial, telecomms and battery-powered systems. The four-switch buck-boost controller, combined with four external N-channel MOSFETs, can deliver from 10 to over 400W of power with efficiencies up to 98 per cent. The buck-boost capability meets automotive applications, where the input voltage can vary dramatically during stop/start, cold crank and load dump conditions. Transitions between buck, buck-boost and boost operating modes are seamless, claims the company, offering a well-regulated output even with wide variations of supply voltage.
A proprietary peak-buck, peak-boost current mode control scheme uses a single inductor current sense resistor to provide a seamless transition between buck, boost and buck-boost regions. Output voltage is delivered with ±1.5 per cent accuracy, while output current accuracy of ±3 per cent ensures accurate constant current regulation, says the company. The LT8390 can be programmed to use a fixed switching frequency between 150 to 650kHz with synchronisation, or it can use internal spread spectrum operation for lower EMI. There is also an input or output current monitor, power good flag, integrated bootstrap diodes and short-circuit protection with fault reporting.
The LT8390 is offered in either a 28-lead 4.0 x 5.0mm QFN or thermally enhanced TSSOP. Industrial grade versions, the LT8390IFE and LT8390IUFD, are also available.