Constant Current Ripple On-Time Control Circuit With Native Adaptive Voltage Positioning Design for Voltage Regulators

In recent years, over one billion transistors have been integrated in one processor, core static current has been increased from 20 to 100 A, and core voltage has been reduced from 2 to 0.7 V. It is a challenge to provide the large output loading requirement for central processing unit application. Single-phase voltage regulator can be widely used in low-voltage converter applications with an output loading of up to approximately 25 A. However, power dissipation, power stress of the components, and efficiency become an issue under a large output load current. The benefits of using multiphase voltage regulators versus single-phase voltage regulator and the value of multiphase voltage regulators become evident when they are implemented. On the other hand, switching power supply requirement has the trend of fast transient response, because it can improve load transient response to reduce output capacitance, especially to central processing unit and high current slew rate load applications, so a pure constant current ripple on-time control circuit for voltage regulators cannot achieve a faster load transient response. Improved transient response using quick dynamic response of the constant current ripple on-time control circuit with native adaptive voltage positioning design for voltage regulators is showed in this chapter. The concept uses the quick dynamic response to filter V OUT at the load transient to change the on-time width dynamically, preventing V OUT from dropping markedly. This quick dynamic response does not need an extra pin to achieve a faster load transient response. Finally, the multiphase voltage regulator with the quick dynamic response of the constant current ripple on-time control circuit for the integrated circuit is implemented by experiment and simulation results to verify their viability and superiority.