ZHCSIO9A August 2018 – June 2021 TPSM831D31
PRODUCTION DATA
For high current applications, D-CAP+ control architecture, combines the benefits of D-CAP constant on-time control with those of multiphase converters. D-CAP+ control ensures that inductor currents of individual phases are fed back so the system has accurate droop control and good current-sharing performance as well an error amplifier is utilized to improve DC accuracy over load and line.
Figure 7-1 illustrates the operational waveforms of D-CAP+ control architecture with 3 phases in steady state. By using the adaptive on-time control concept, a pseudo fixed switching frequency of SW_CLK is generated by comparing the summed inductor currents, ISUM, and the error amplifier output, EA, signal. By distributing the switching signal to different phases, all phases can be perfectly interleaved in steady state. During load transients, the switching frequency is varied to improve the transient performance as shown in Figure 7-2. Variable switching frequencies of different phases can be observed.
One important feature of a multiphase converter is the capability to dynamically add or drop the number of operational phases based on load conditions. The goal is to optimize efficiency while maintaining good load transient performance.