New multiphase DC-DC controller packs efficiency and accuracy into small footprint

Written by Joshua Israelsohn May 17, 2010 Hits: 547 Favorites

0.0 (0)

Applications as disparate as computational resources, telecom systems, and smart instrumentation depend on high-current low-voltage power sources to drive modern data- and signal-processing ICs, memory subsystems, I/O channels, and ancillary circuits. As IC fabrication processes have evolved, allowing growing functional densities, operating voltages have fallen and, with them, supply tolerances.

To support tight supply tolerances, at the core of Linear Technology’s LTC 3829 3-phase DC-DC controller is a 0.6 V reference boasting an accuracy of ±0.75%. Adding to the controller’s ability to maintain tight output voltage control is a differential sense amplifier that measures the voltage at the point of load, eliminating current-proportional errors due to trace resistance.

The LTC 3829 can monitor the output current by means of either a 2 mΩ sense resistor or by measuring across the output inductor’s DC resistance. Using the inductor’s DC resistance can give rise to a current measurement temperature-coefficient error due to the significant thermal coefficient associated with copper’s resistivity. The ‘3829 provides for a compensation scheme that corrects for the copper-based tempco error that requires only a resistor divider and an NTC thermister.

To reduce switching losses at light and moderate loads, the controller can idle either one or two of its three channels, returning them to service when load currents cross resistor-programmable thresholds. Additional flexibility is available by combining two LTC 3829 controllers to form a six-phase power conversion subsystem. In this configuration, the two controllers operate in the appropriate fixed-phase relationship with respect to one another to produce currents to 150 A while maintaining voltage accuracy and low ripply.

User reviews

There are no user reviews for this listing.

To write a review please register or login.

Written by :

Joshua Israelsohn