Research And Design Of High Frequency Multiphase DC-DC Converter

The processors are developing in the direction of more cores,faster clock frequencies,and greater load currents.This requires the power supply for the processor to have a faster transient response speed and a larger load capacity.Based on the background of powering modern processors,the high-frequency multi-phase DC-DC converters is presented in this thesis.Based on the miniaturization and integration of processor power supply and the development trend of low-voltage and high-current load power supply,this thesis proposed a20 MHz 4-phase buck converter.Based on the transient response speed requirement of a few amperes per nanosecond of the processor power supply,this thesis adopted a clock synchronization adaptive window hysteretic control scheme,and proposed a calibration circuit to make the controller guarantees clock synchronization and frequency lock even in mismatch and low output voltage condition.Based on the processor power supply’s wider output power range and more power supply modes,better energy saving,this thesis proposed a adaptive nearoptimal DVS response circuits.Based on the demand for high conversion efficiency within a wider load of the processor power supply,used all-NMOS powerstage,bootstrap technology,adaptive dead time technology,APC technology,DCM/PFM technology in this design.In order to ensure the current balance between multiphase,proposed the cooperation of master-slave active current sharing technology and trimming circuit to ensure that the converter can still maintain current balance under mismatches such as inductance DCR.The proposed converter is implemented in the SMIC 0.18 BCD process.The input voltage is 3.3V,the output voltage is 0.8V-1.8V,and the external inductor and capacitor of 200 n H and 2.2 are used.The post simulation results showed that under a load transient of4A/ns,the undershoot or overshoot of the output voltage does not exceed 140 m V,and the settling time does not exceed 300 ns.Under the 0.8V-1.8V reference voltage tracking,the up and down tracking time of the output voltage is 466 ns and 485 ns,respectively.In terms of efficiency,the converter has a conversion efficiency of over 80% in the 99.3% load range.And the peak efficiency reaches 91%.In terms of current balance,even if the inductance DCR is mismatched by more than 20%,the current distribution error of each phase can still be maintained within2.6%.