Research And Design Of High Performance Loops Adapt To High Accuracy And Fast Transient Response DC/DC Converter

Due to the critical requirement in transient response speed and accuracy,COT control and current control become the most favored control strategy in power systems.COT control is known for its fast transient response and high efficiency at light load,and the appearance of ACOT makes it to eliminate some problems coming with nonconstant-frequency operation,which brings a new spring to COT’s developments.However,two essential issues that subharmonic emerges in low ESR operation and the intrinsic DC offset is introduced by control mode still exist even if it’s under ACOT control.An advanced COT control loop based on internal active ripple compensation(ARC)strategy with adaptive offset cancellation(AOC)was proposed by deep study in the fundamentals of subharmonic and offset mechanism.Half-period sensing combined with AOC procedure high accuracy COT control loop accomplishes ripple compensation and offset cancellation completely at the same time by utilizing active DC value exaction and superimpose network.The high accuracy COT loop was realized and verified in a synchronous buck regulator with UTC40VBCD050 process.Current control mode is famous for its high control accuracy,excellent dynamic response speed and cycle by cycle current limit,but the fixed condition stability problem determines the demand of slope compensation.Over-compensation and undercompensation occur frequently when compensation network is integrated in specific power topology.Adaptive slope compensation eases it in some degrees,but its complexity restrains its promotion.Constant frequency operation triggered by clock lowers light load efficiency.For covering those shotcomings,peak current control loop with EB circuit for a wide range of application was proposed.Non-fixed compensation is equivalent to variable power topology application,and EB circuit enhances the efficiency quality of the system.The high efficiency peak current mode control loop was applied to a PWM controller which was realized and fabricated with HHNEC40VBCD035 GE process.Test results of the fabricated products shows its anastomosis when compared with the design simulation.