Multi-frequency-point RC oscillator

Abstract

The invention discloses a multi-frequency-point RC oscillator, and relates to the technical field of integrated circuits. The oscillator comprises a frequency selection module, a charging and discharging module, a transmission gate module and a comparison output module. The frequency selection module is connected to the charging and discharging module and the transmission gate module through a first switch, and the frequency selection module and the charging and discharging module are connected to the comparison output module through the transmission gate module; the frequency selection modulecomprises a plurality of resistors and a selector connected to the plurality of resistors, and the selector switches on part or all of the plurality of resistors according to the received frequency selection signal so as to output different first voltages to the transmission gate module; and the transmission gate module outputs the first voltage output by the frequency selection module and the second voltage of the charging and discharging module to the comparison output module, compares the first voltage and the second voltage with capacitor voltage in the charging and discharging module, and switches on / off a first switch and a second switch, so that the charging and discharging module repeatedly charges / discharges to output an oscillation signal.

Description

technical field [0001] The invention relates to the technical field of integrated circuits, in particular to a multi-frequency point RC oscillator. Background technique [0002] Oscillators are widely used as clock sources in electronic equipment, especially in the field of communication. There are four common types of oscillators: ring oscillators, LC / RC oscillators, crystal oscillators, and relaxation oscillators. Ring oscillators are greatly affected by voltage and temperature, and their frequency is unstable. They are mostly used in phase-locked loop circuits; LC / RC oscillators are divided into LC oscillators and RC oscillators. Among them, LC oscillators occupy a large area and are not easy to integrate. Less used; RC oscillator has a simple structure, good frequency stability, easy on-chip integration, and is widely used; crystal oscillator has high precision and excellent temperature coefficient, but it occupies a large area and consumes high power, so it cannot be i...

AI Technical Summary

Problems solved by technology

The frequency accuracy of this oscillator is poor, and there is only one frequency point. When the system needs clocks of different frequencies in different application scenarios, multiple clocks with different frequencies need to be built in, which takes up a large area and is not convenient for system integration.

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