Synchronous buck-boost controller regulates up to 250W

November 27, 2014 // By Graham Prophet
LT3790 is a synchronous buck-boost DC/DC controller that delivers up to 250W of power with a single IC. Its 4.7V to 60V input voltage range suits it for automotive and industrial applications.

Its output voltage can be set from 0V to 60V, for use as a voltage regulator or battery/supercapacitor charger. The LT3790's internal 4-switch buck-boost controller operates from input voltages above, below or equal to the output voltage, for applications such as automotive, where the input voltage can vary dramatically during stop/start, cold crank and load dump scenarios. Transitions between buck, pass-through and boost operating modes are seamless, offering a well regulated output in spite of wide variations of supply voltage. The LT3790's design has three control loops to monitor input current, output current and output voltage.

The LT3790 uses four external switching MOSFETs and can deliver up to 250W of continuous output power with efficiencies up to 98.5%. Output current accuracy of ±6% ensures precise current regulation while ±2% output voltage accuracy offers a precise output voltage, making it suitable for charging applications. Multiple LT3790s can be paralleled for higher power requirements. Its switching frequency can be programmed between 200 kHz and 700 kHz or synchronised to an external clock. Additional features include output disconnect, input and output current monitors, a C/10 charge termination and integrated fault protection.

The LT3790EFE is available in a 38-lead thermally enhanced TSSOP package, priced starting at $4.75 (1,000); there are extended temperature and high temperature versions.

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