This paper presents a novel buck converter with dual-loop control technology, which does not need to detect the inductor current directly. The structure of the control loops is easy to implement, one loop controls the output voltage, and the other controls the switching frequency. With the dual loops control mechanism, the output voltage and switching frequency can be accurately controlled only by measuring the output and input voltage, without sensing the inductor current. The buck converter can generate an output voltage of 1.0–2.5 V when the input voltage and load current are 3.0–3.6 V and 100–500 mA, respectively. The design was verified by SIMPLIS. The simulation results show that the switching frequency variation is less than 1% at the output voltage of 1.0–2.5 V. The recovery time is less than 1.5 μs during the load change. The circuit can be fabricated by using the TSMC 0.35μm 2P4M CMOS processes. The control scheme, theoretical analysis and circuit implementation are presented in this paper.
