A 90–240 MHz Hysteretic Controlled DC-DC Buck Converter With Digital Phase Locked Loop Synchronization

Pengfei Li, Deepak Bhatia, Lin Xue, Rizwan Bashirullah
2011 IEEE Journal of Solid-State Circuits  
This paper reports a digital phase locked loop (D-PLL) based frequency locking technique for high frequency hysteretic controlled dc-dc buck converters. The proposed converter achieves constant operating frequency over a wide output voltage range, eliminating the dependence of switching frequency on duty cycle or voltage conversion range. The D-PLL is programmable over a wide range of parameters and can be synchronized to a clock reference to ensure proper frequency lock and switching operation
more » ... outside undesirable power supply resonance bands. The stability and loop dynamics of the proposed converter is analyzed using an analog equivalent PLL behavioral model which describes the dc-dc converter as a voltage-controlled oscillator (VCO). We demonstrate a 90-240 MHz single phase converter with fast hysteretic control and output conversion range of 33%-80%. The converter achieves an efficiency of 80% at 180 MHz, a load response of 40 ns for a 120 mA current step and a peak-to-peak ripple less than 25 mV. The circuit was implemented in 130 nm digital CMOS process.
doi:10.1109/jssc.2011.2139550 fatcat:sqkhsjtpsbckdfxfxm4squhy4m