A High-Accuracy Hysteretic DC-DC Converter Using A Spread-Spectrum EMI Suppression Technique with Double Gold Codes

This paper presents a hysteretic buck-boost converter using a double gold code spread-spectrum (DGCSS) technique to suppress the electromagnetic interference (EMI). To enhance the spread-spectrum effect, the delay time and hysteretic window are both implemented with the uniform gold code sequence to improve the randomness of the random number generators. The proposed DGCSS randomizes the switching frequency and results in low EMI in the power spectral density. The high-accuracy feed-forward current sensing with a compensator improves the load regulation and eliminates the tradeoff between the in-phase accuracy and output ripples. The prototype is simulated in TSMC 180 nm CMOS process. Simulation results show that the peak power efficiency of 90.97% and the peak-spur suppression of 30.58 $\mathrm{dB}\mu \mathrm{V}$ are achieved. The average output voltage ripple is 21 mV and the recovery time is 7.2 $\mu \mathrm{s}$.