An Integrated Transient Enhancement Circuit Suitable for Buck Converter With Large Output Capacitor

This brief proposes an integrated transient enhancement circuit (TEC) suitable for Buck converter with large output capacitor, which is composed by resistors, capacitors, and operational amplifier. The presented TEC brings in two additional zeros and two additional poles in the system control loop without affecting the low frequency characteristics. The introduced zeros and poles extend the bandwidth of the loop as they are placed before crossover frequency. With load transient response, the system response speed can be accelerated and the overshoot/undershoot voltage can be reduced. A current-mode Buck converter with the proposed TEC is implemented in a 0.35 <inline-formula> <tex-math notation="LaTeX">${\mu }\text{m}$ </tex-math></inline-formula> BCD process. With a 330-<inline-formula> <tex-math notation="LaTeX">$\mu \text{F}$ </tex-math></inline-formula> output capacitor and a 2.5-A/<inline-formula> <tex-math notation="LaTeX">${\mu }\text{S}$ </tex-math></inline-formula> load change, the undershoot/overshoot voltage and recovery time are 32/46 mV and 74/88 <inline-formula> <tex-math notation="LaTeX">${\mu }\text{s}$ </tex-math></inline-formula>, respectively, which are improved by 39% compared with those of converter without proposed TEC.