Sub-1-V Fast-Response Hysteresis-Controlled CMOS Buck Converter Using Adaptive Ramp Techniques

This paper presents a sub-1-V fast-response hysteresis-controlled buck converter using adaptive ramp techniques. The proposed buck converter can be operated at a lower supply voltage and adopts the inverter-based low-voltage error amplifier, which is better than conventional two-stage amplifiers in the low-voltage applications. Using hysteresis-controlled and fixed-voltage band techniques, the proposed buck converter can improve the transient response. Moreover, the sub-1-V structure allows the proposed converter to consume low power dissipation. The proposed chip has been implemented with TSMC 0.18- μm 1P6M CMOS processes. The operating frequency of the proposed converter is from 0.5 to 1.25 MHz, with an inductor of 4.7 μH and a capacitor of 47 μF. Experimental results show that the proposed converter achieves fast transient response under 11 μs and can be directly powered with 1-V supply voltage. In addition, the output voltage is 0.5 V, the load current is 300 mA, and the power efficiency can be up to 91.5%.