an oscillating circuit

Abstract

The present application discloses an oscillating circuit. The amplifying module and the clamping module of the oscillating circuit constitute a low-dropout linear voltage regulator, which limits the potential of the second terminal of the clamping module to a preset voltage. Since the second terminal of the clamping module The output impedance of the terminal is very small within the bandwidth of the amplifying module, which can provide this point with the effect similar to the AC virtual ground. The virtual ground effect of this point makes the oscillation module realize the improvement at low frequencies without a large capacitor occupying a large wafer area. The purpose of the negative resistance of the circuit is beneficial to reduce the wafer area required by the oscillator circuit. In addition, due to the existence of the low-dropout linear voltage regulator, even if the capacitance in the oscillation module is adjusted to meet the consistency of the wafer, it will not cause the potential change of the second terminal of the clamp module, and the final output oscillation signal The upper limit will not change, which is beneficial to ensure the oscillation amplitude of the oscillation signal output by the oscillation circuit and ensure that the oscillation circuit has good performance.

Description

technical field [0001] The present application relates to the technical field of integrated circuits, and more particularly, to an oscillator circuit. Background technique [0002] Crystal oscillators have found numerous applications in various electronic systems. With the continuous development of wireless communication technology and the popularization of portable mobile devices, the clock signal has become a necessary signal for the cooperative work of various internal devices. [0003] Real Time Clock (RTC) signals are used in many digital integrated circuits. The key part of generating real time clock signals is the 32.768kHz crystal oscillator circuit. The circuit has put forward newer and higher requirements, which are concentrated in the aspects of high stability, wide power supply voltage range, small area, low power consumption and low cost. [0004] In order to improve the negative resistance of the circuit under the condition of limited current in the crystal o...

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Problems solved by technology

[0004] In the crystal oscillator circuit in the prior art, in order to increase the negative resistance of the circuit under the condition of limited current, it is necessary to set a relatively large MOM capacitor to make the transconductance negative resistance of the pull-up transistor work, and the large capacitor occupies a large amount of energy. The wafer area is not only difficult to meet the requirements of small circuit size, but also the larger wafer area makes the circuit cost high

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