Differential voltage-controlled oscillator (VCO) circuit structure for reinforcing single-event transients (SET)

Abstract

The invention discloses a differential voltage-controlled oscillator (VCO) structure for reinforcing single-event transients (SET). In order to improve the anti-SET capability of the conventional symmetrical-load VCO structure, the invention has two improvements that: first, tail current tube drain Vp of all delay units are in a short circuit so as to improve the immunity of a VCO circuit to SET effect; and second, two diode-connected PMOS pipes in symmetrical loads are cross-coupled and connected so as to ensure that the output of the VCO structure after the Vp short circuit still has differential characteristics. The SET sensitivity of the improved VCO is greatly reduced. The structure can effectively improve anti-SET capability, and also has the characteristics of simple structure, high working frequency and good linearity.

Description

technical field [0001] The present invention mainly relates to the design field of a voltage-controlled oscillator (VCO) in a single-event transient (SET) reinforced phase-locked loop circuit, in particular to a differential voltage-controlled oscillator (VCO) for single-event transient (SET) reinforcement. VCO) circuit structure. Background technique [0002] A voltage-controlled oscillator (Voltage-controlled-Oscillator, VCO) is mainly used in circuits such as clock generation, frequency multiplication and frequency synthesis. In radiation environments, such as orbital space where satellites operate, electronic equipment with voltage-controlled oscillator (VCO) circuit modules is highly susceptible to single event effects. Single event transient is an effect caused by high-energy particles bombarding the sensitive junction of the circuit. Due to the energy deposition of the particles after the bombardment, impact ionization is caused, and the ionized electron-hole pairs a...

AI Technical Summary

Problems solved by technology

[0003] For conventional symmetrically loaded delay cells such as figure 1 shown), when the high-energy particles bombard the drains of the PMOS transistors M5, M6, M3 or M4 of the differential delay unit, the high-energy particles will cause the drains of the MOS transistors to undergo impact ionization on their entire crossing tracks to generate electron-air Hole pairs, electron-hole pairs are transmitted and collected under the action of the electric field and concentration gradient in the PMOS tube, causing the voltage of the differential output node OUT+ or OUT- of the voltage-controlled oscillator (VCO) to rise sharply instantaneously, making the voltage control The output clock of the oscillator (VCO) is ahead of the reference clock, thereby generating a phase difference; conversely, when a high-energy single particle bombards the drain of the NMOS transistor M1 or M2 in the differential delay unit, the high-energy particle will also cause the drain of the MOS transistor to occur The impact ionization generates electron-hole pairs at the same time, and the electron-hole pairs are transmitted and collected under the action of the electric field and dense gradient in the NMOS tube, resulting in the voltage of the differential output node OUT+ or OUT- of the voltage-controlled oscillator (VCO) Instantaneous rapid decline, causing the output clock of the voltage-controlled oscillator (VCO) to lag behind the reference clock of the PFD, and also produce a phase difference

Images