宽负载应用的自适应关断时间Boost电路

An Adaptive-Off-Time Boost Circuit Applied in Wide Load

设计了一种新型自适应关断时间(AFT)模式Boost电路。不同于传统的采样输入/输出电压的自适应电路,该AFT模式Boost电路直接采用真实的占空比信息,设置了自适应比较点,解决了开关频率受负载电流影响的问题。基于0.5μm CMOS工艺对电路进行仿真验证。结果表明,当输入电压在2.4~4.2V、负载电流在0.3~1.2A范围内变化时,该AFT模式Boost电路的工作频率稳定在967~972kHz之间,频率变化范围仅为传统自适应电路的14.3%。

A new adaptive-off-time（AFT）boost circuit was designed.It was different from the traditional adaptive circuit which sampled the input and output voltages.The real duty cycle information was sampled in the proposed circuit by setting the adaptive comparison point,and the problem that the switching frequency would be affected by the load current in traditional adaptive circuit was solved.The AFT boost circuit was simulated and verified in a 0.5μm CMOS process.The results show that the operating frequency was stabilized between 967 kHz and 972 kHz,and the frequency variation range was only 14.3% of the traditional adaptive-off-time circuit when the boost regulator＇s input voltage range was from 2.4 Vto 4.2 Vand the load current range was from 0.3 Ato 1.2 A.