Configurable oscillator circuit for high-speed analog-to-digital converter

Abstract

The invention discloses a configurable oscillator circuit for a high-speed analog-to-digital converter, which belongs to the field of oscillators and comprises a ring oscillator and an adjustable RC delay circuit. The adjustable RC delay circuit is connected to the ring oscillator by adjusting different numbers of resistors and capacitors to control the oscillation frequency of the oscillator. According to the invention, a plurality of high-precision resistors and capacitors are added in the ring oscillator circuit, so that the loop delay can be accurately controlled, and the oscillation frequency is controlled; a switch is added between a loop and a resistor capacitor, the size or the number of resistors and capacitors connected to the circuit is selected through the switch, and the transmission delay of the loop is changed along with the difference of the total resistance and capacitance, so that the configuration of the oscillation frequency is realized.

Description

technical field [0001] The invention relates to the technical field of oscillators, in particular to a configurable oscillator circuit for high-speed analog-to-digital converters. Background technique [0002] Oscillator circuits are often used to generate high-frequency signals, especially in high-speed analog-to-digital converters. like figure 1 As shown, the ring oscillator is a ring circuit composed of n (n is an odd number) NOT gates. Looking at the output of the oscillator, the output signal will periodically flip from high level to low level and then to high level, thereby generating a fixed frequency oscillation signal. [0003] If the delay time from when the input of a single inverter becomes 1 / 2VDD to when the output becomes 1 / 2VDD is regarded as the delay time Δt of a single inverter, its expression can be described as: [0004] [0005] where t PLH , t PHL Respectively, the transmission delay of a single inverter output from low to high and from high to ...

AI Technical Summary

Problems solved by technology

[0009] The advantage of the ring oscillator is that the circuit is simple and easy to start, but there is a problem that the frequency of the delay network is not easy to choose flexibly, and it is necessary to multiply the number of NOT gates in order to generate a lower frequency signal.

Because there is a certain error in the delay time of the gate circuit, this will also lead to a large error between the actual oscillation frequency and the estimated value, so the direct use of the series connection of NOT gates cannot perform high-quality frequency output, and also limits the frequency range.

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