To achieve high power and high efficiency over a wide load range, an improved hybrid hysteresis voltage mode for Buck circuit is proposed in this paper. The strategy and workflow of the proposed improved hybrid hysteresis voltage mode are demonstrated step by step. The output voltage performance of the Buck circuit with proposed hysteresis voltage mode is compared with the same circuit with typical hysteresis voltage mode. Numerical simulation results show that with the introduction of the PD link, the overshoot can be completely controlled or eliminated; with the introduction of the dynamic voltage reference, the static difference can be completely negligible; relatively stable input voltage improves its steady-state working frequency and the electromagnetic interference significantly. Thus, the proposed control strategy can not only achieve satisfied performance, but also provide a basis for further design and optimization. INDEX TERMS Buck circuit, Hysteresis voltage mode, Ripple elimination, Static difference.

To achieve a designed and fixed operating frequency for a controller with high dynamic performance and a high load capacity, a hybrid constant on-time (COT) voltage mode for a Buck circuit is proposed and discussed in this paper. The proposed hybrid strategy is a combination of the classical COT method, a dynamic reference voltage technology and a proportional–differential (PD) module. The workflow is demonstrated in brief, simulations of a Buck circuit with the proposed hybrid COT mode are conducted and comparisons with developed pulse-width modulation (PWM) technology and the hysteresis mode are made. The results show that, with the help of the proposed control scheme, impressive performance from the Buck circuit can be expected. The operating frequency can be fixed well by the hybrid technology without losses of performance and robustness in steady state and will not jump much even with the sudden change of the inputs and the load. The proposed control strategy contributes to the foundation of circuit design and optimization.