摘要
开关电源需要适应不同开关频率的要求。作为保证电流模DC-DC变换器环路稳定的重要部分,斜坡补偿电路也需要满足这一要求。基于峰值电流模控制(PCMC)的降压型DC-DC变换器,阐述了斜坡补偿的原理和多种斜坡补偿方案,设计了能够自适应开关频率的二次斜坡补偿电路。在0.35μm BCD工艺下,对不同工作频率下的斜坡补偿电路和整体电源电路进行了仿真验证。结果表明,在全频率范围内没有出现次谐波振荡和过补偿现象,电路工作稳定。该斜坡补偿电路适用于开关频率可调的开关电源领域。
Switching power supplies need to meet the requirements of different switching frequency.As an important part guaranteeing the loop stability of current mode DC-DC converter,the slope compensation circuit should also meet the requirements of different switching frequency.Based on the peak current mode control(PCMC)buck DC-DC converter,the slope compensation principle and a variety of slope compensation scheme were presented.A quadratic slope compensation circuit of adaptive switching frequency was proposed.Based on the 0.35μm BCD process,the slope compensation circuit and the whole switching power supply circuit were simulated and verified.The results showed that the sub-harmonic oscillation and over-compensation did not appear within full frequency range,and it worked stably.The slope compensation circuit was suitable for switching power supplies of adaptive switching frequency.
引文
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