A novel single-event-hardened charge pump using cascode voltage switch logic gates

Abstract

A single-event-hardened charge pump for phase-locked loops is proposed based on radiation-hardened-by-design technique (RHBD). By applying a novel digital control circuit between the charge pump and the low-pass filter, the vulnerability of the charge pump to single event transients (SET) is considerably reduced. Besides, this control circuit does not change the original structure of the charge pump as well as the loop parameters. Simulation results based on SMIC 130 nm bulk CMOS technology showed a significant reduction of the voltage perturbation in the input of the voltage-controlled oscillator. Moreover, by implementing the proposed structure to the system, SET tolerance in VCO and DIV is improved to some extent, and the output noise of the charge pump is smaller than the original structure. In fact, the period jitter of the phase-locked loop is reduced by 12.5%–22.5% with the changes in operating frequency. The newly added circuit has the fairly low sensibility to SETs if it is properly designed.