带自适应斜坡补偿的COT控制Buck变换器

A COT Controlled Buck Converter with Adaptive Slope Compensation

提出了一种采用自适应斜坡补偿(ARC)的恒定导通时间控制Buck变换器。引入了两个斜坡电压,实现对电感电流下降斜率的检测;通过负反馈环路调节斜坡斜率,使斜坡斜率跟随电感电流下降斜率的变化。最终斜坡补偿带来的额外极点被固定下来,以便于补偿设计。在此基础上,引入瞬态增强电路,提高了负载阶跃响应速度。在5 V输出电压下,负载从3 A到100 mA阶跃时,输出上冲电压减小了150 mV,恢复时间缩短了10μs。负载从100 mA到3 A阶跃时,输出下冲电压减小了130 mV,恢复时间缩短了12μs。

A constant on-time control buck converter using adaptive ramp compensation(ARC) was proposed. Two slope voltages were introduced to detect the falling slope of the inductor current. The compensation slope was adjusted through a negative feedback loop, so that the compensation slope followed the falling slope of the inductor current. Finally, the extra poles brought by slope compensation were fixed, making it easier to compensate the design. On this basis, the transient enhancement circuit was introduced to improve the load step response speed. Under 5 V output, when the load was stepped from 3 A to 100 mA, the output voltage overshoot was reduced by 150 mV, and the recovery time was shortened by 10 μs. When the load was stepped from 100 mA to 3 A, the output voltage undershoot was reduced by 130 mV, and the recovery time was shortened by 12 μs.