【摘要】 提出一种改进的斜率补偿方式,用以改善恒定导通时间控制模式Buck变换器的稳定性。与传统方法相比,所提方法以数字化控制的方式间隔周期提供斜率补偿信号,能更加有效地消除次谐波振荡。此外,该方法可根据相邻周期关断时间的偏差来自适应地调节补偿信号的斜率。这使得系统在稳态时仅需少量的斜率补偿,有效地降低了补偿信号对恒定导通时间控制快速响应能力的影响。通过理论量化分析和实验对比验证了所提方法的可行性。更多还原

【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.更多还原