Controlled slew rate enhancement circuit for error amplifier in high frequency DC-DC converters

Abstract

Modern power applications are driving the demand for power supply systems with fast transient response. A novel controlled slew-rate enhancement (CSRE) circuit for error amplifier in high frequency DC-DC converters is proposed to improve transient responds of DC-DC converters under large load current changes. The CSRE circuit with embedded current-detection is connected in parallel with the error amplifier. By detecting the maximum difference current corresponding to the maximum derivation of the output voltage and optimizing sizes of the CSRE circuit, the CSRE circuit can be controlled properly so that the system stability can be guaranteed in various operating conditions. When the proposed circuits was employed in 100 MHz buck DC-DC converters implemented in SMIC 0.18 mum CMOS process, the simulation results of transient responses show that the CSRE circuit improves the average 1% settling time by 20 times and overshoot by 16 times, while the total quiescent power is only increased by less than 7.1.