Modelling and stability analysis of current-mode switching power management IC with novel internal frequency compensation

Power management ICs especially switching regulators are widely used. A high performance error amplifier and novel internal frequency compensation network for current-mode buck regulators are presented. The proposed compact structure eliminates the use of feedforward capacitor in traditional method. Also the loop stability is independent of load resistance and the ceramic output capactor's ESR, which reduces the complexity of the design and saves the PCB space. A current-mode DC-DC buck regulator with proposed structure has been fabricated with a 0.5μm CMOS process for validation. With 2.7V~5.5V input range, the chip works steadily. The output voltage can recover within 20μs for 500mA load step. High efficiency up to 96% is achieved through internal synchronous rectification.