Accurate oscillator circuit supporting multi-frequency output

Abstract

The invention discloses an accurate oscillator circuit supporting multi-frequency output, and relates to the field of integrated IC integrated circuits. The circuit comprises a ring oscillator circuitcomposed of an odd number of inverters. The output end of each inverter is connected with a capacitor; the source electrode of each inverter is respectively connected with a reference current Iref which enables each stage of delay time of the ring oscillator circuit to be a fixed time unit; the reference current Iref is output by the band-gap reference current source circuit; the band-gap reference current source circuit comprises a current source starting circuit, a primary operational amplifier, a current generator with reference voltage in direct proportion to absolute temperature and a double-voltage-domain reference current source conversion circuit which are sequentially connected, and the double-voltage-domain reference current source conversion circuit completes conversion of reference current working in different voltage domains. The band-gap reference current source circuit is adopted to generate the reference current Iref, and the oscillation frequency of each stage of inverter in the ring oscillator circuit is accurately controlled through current mirror mirroring.

Description

technical field [0001] The invention relates to the field of integrated IC integrated circuits, in particular to a precision oscillator circuit supporting multi-frequency output, which is suitable for fingerprint sensors, the Internet of Things and other fields. Background technique [0002] Oscillators are very important in electronic systems and are used in a wide range of applications, from providing clocks for digital systems to generating carrier signals in radio frequency circuits. There are also many structures of oscillators, including LC oscillators, ring oscillators, cross-coupled oscillators, Colpits oscillators, etc., and the performance parameters of different structures are quite different. [0003] figure 1 For the commonly used ring oscillator using inverters, only three inverters are connected end to end to form a closed loop in the figure. This oscillator consists of an odd number of inverters, and its structure is very simple. When the circuit is first ...

AI Technical Summary

Problems solved by technology

However, the device is noisy, and the X, Y, and Z point voltages will be disturbed. As a result, the noise will continue to amplify, and when the signal finally reaches the power supply voltage, it will oscillate.

At the beginning, the voltages of points X, Y, and Z are at the logic threshold voltage, and the noise disturbs the voltages of points X, Y, and Z, and continues to amplify, and finally reaches the amplitude of the power supply voltage, resulting in inaccurate clock signal output

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