Abstract：A novel adaptive ramp compensation scheme is proposed to improve stability for Buck converters with ripple-based constant on-time control. Compared with traditional compensation approaches, the new method eliminates sub-harmonic oscillation more effectively by using digital control approach to generate "every other cycle" ramp compensation signal. Furthermore, the slope of ramp compensation is adaptively adjusted according to the off-time difference between two consecutive cycles. These features minimize the required ramp amplitude at steady state and effectively avoid over-compensation, and thus, reduce the impact on transient response performance of constant on-time control. Theoretical analysis and experimental results are provided to verify the proposed scheme.
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2017, Vol. 32 
