A Low-Noise Fast Transient Response Buck Converter Suitable for Sensor Networks with New Transient-Accelerated-Circuits

This paper proposed a low-noise fast-transient-response continuous-time delta-sigma-modulator (CT-DSM) buck converter suitable for sensor networks with new transient-accelerated- circuits. That features an integral loop filter with noise shaping and superiority of oversampling for effective spurious-noise reduction. Furthermore, the transient-acceleratedcircuits (TAC) use DCR current-sensing circuit and hysteresis-voltagecontrolled (HVC) circuit to speed up the transient response. Thus, the proposed buck converter maintains a low spurious noise and fast transient response. The buck converter is simulated using HSPICE and fabricated in TSMC 0.18um 1P6M CMOS process with a chip area of 1.19mm x 1.05mm. The measured results show that the transient recovery times with TAC are both 3 mu s, which is 4 mu s and 5 mu s faster than the recovery time without TAC, and the undershoot and overshoot voltage is 22 mV and 25 mV, when the load current changes from 100mA to 500mA and from 500mA to 100mA. The output to noise ratio (ONR) of the output spectrum is 78.6dB, with oversampling frequency of 10 MHz. The maximum power efficiency is 91.8%, when the load current is 200mA and output voltage is 2.5V.