New-Tech Europe | December 2016 | Digital Edition

The QFN packages used for these modules (see figure 2) include large pads that connect to key nodes in the power train, ensuring good Ohmic contact and minimizing EMI. These pads also provide excellent heatsinking for the module, which result in the package’s low junction- to-case thermal resistance and superior thermal performance. Combined with the regulator’s intrinsic high power conversion efficiency that minimizes internal losses, these modules can deliver full power with little or no de-rating required – see figure 3. This solid performance specification allows the modules to be easily used in multiple applications simply by replacing a few passive components. This saves development time and R&D expense and results in a faster time- to-market and a more competitive product positioning. Summary Today’s fast paced innovative electronic design environment places enormous pressure on the practicing engineer to complete his/ her designs in record times without any sacrifice in performance or cost. Coming to their rescue is a family of fully integrated power modules that are conceived, designed and produced to help turn the development of a power delivery subsystem into an easy five step process: (1) Know your requirement (2) Select the appropriate module (3) Calculate the values of the housekeeping components – see figure 4 below (4) Layout your PCB (5) Test and verify your prototype … then move on to your next achievement! The first three tasks should take less than 30 minutes for guaranteed

Figure 5. The XR79206 achieves nearly 95% efficiency at 700kHz switching frequency and VIN = 24V

was key to their design brief and hence the requirements of modern electronic equipment, but do so at a competitive price. Modules do not have to be a compromise The controllers used in Exar’s power modules offer the same performance as their ICcounterparts and provide exceptional line and load regulation. Furthermore, to achieve maximum efficiency at both ends of the output current range, operation can be switched from the regular constant current mode (CCM) to discontinuous conduction mode (DCM) to save power at light load currents. These modules also

provide all the usual protection features, such as over current, over temperature, short circuit and under voltage lockout, to ensure safe operation under abnormal operating conditions. Additional features include: programmable soft-start, a programmable hiccup current limit with thermal compensation, flags for Power-Good and Precision Enable, and an integrated bootstrap diode. Where the module approach really wins out is in integrating the control IC, with its rich feature set, together with the power train components, which have been selected for optimal switching performance, in one very small, cost-effective package.

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