A low power 3.1–7.5 GHz tunable pulse generator for impulse radio UWB

Abstract

A novel energy-efficient tunable impulse radio ultra wide band (IR-UWB) pulse generator (PG) for the high data rate 3.1 – 7.5 GHz band applications is proposed. Glitch generator, switched ring oscillator, buffer and pulse shaping filter are the key components. The circuit is scalable both in bandwidth and center frequency. The glitch generator combines falling edge of the input signal and its delayed inverse, allowing the impulse duration to be tuned over a wide range (250 – 660 ps) by varying the delay between the edges. The generated impulse duration approximately defines the PG's signal width and thus its spectrum bandwidth. The ring oscillator frequency, which determines the spectrum center frequency, is controlled by the gate control voltage of the PMOS transistor used as an inverter feedback in the ring oscillator. Post-layout simulations show the pulse amplitude of 261 mV and the pulse duration around 700 ps. The total power consumption is only 697 µW with a supply voltage of 1.8 V. The PG is designed in UMC 0.18µm CMOS technology with the total chip area of 602×587 µm2.