1 Introduction

The reference design describes a four-phase interleaved buck converter which can be used in ADAS and IVI applications. As table 1 shows, the converter operates over a wide input voltage range of 6.5V to 36V to deliver a single 4.5V regulated output. The output tolerance has better than 1% steady state set-point accuracy at load currents up to 42A. The reference design also employs dynamic phase shedding to make sure excellent light load efficiencies, achieving as high as 81% efficiency at 15mA load current. With peak current mode control, the converter achieves ±8.3% output voltage perturbation, for a load step 21A to 86A at 65A/us. The LM5137F-Q1 is dual phase stackable controller, this reference design uses two LM5137F-Q1 to obtain a single output four-phase interleaved voltage regulator. One LM5137-Q1 is used as a primary controller and the second LM5137-Q1 is used as a secondary controller. In the stacked configuration, COMP1 and COMP2 of each controller are all connected together. Being a single output interleaved design, all outputs are connected together, with each phase being synchronized to a clock interleaving each phase, shifted 90 degrees apart. Four-phase interleaving effectively reduces ripple current compared to a single-phase design, thus reducing ripple voltage and RMS ripple currents on both the input and output capacitors.