Relaxation oscillator for increasing frequency-control current linearity

Abstract

The invention discloses a relaxation oscillator for increasing frequency-control current linearity. The relaxation oscillator comprises a charge and discharge circuit, a control circuit and a floating charge and discharge capacitor arranged between the charge and discharge circuit and the control circuit. The control circuit detects voltage of the floating charge and discharge capacitor and outputs a control signal. The output signal of the oscillator is determined by only the charge process of the floating charge and discharge capacitor, so that complete-period delay of the oscillator is decreased and frequency-control current linearity of the oscillator is increased. The floating charge and discharge capacitor is formed by parallelly connecting two equal capacitors C1 and C2, and two pole plates of the capacitors C1 and C2 are cross-connected with each other; two ends of the floating charge and discharge capacitor are symmetrical, so that the influence of micro stray capacitance at two ends of the floating charge and discharge capacitor upon the output of the oscillator is decreased.

Description

technical field [0001] The invention relates to the field of CMOS integrated circuits, in particular to a relaxation oscillator which improves the linearity of frequency-controlled current. Background technique [0002] In VLSI, the clock signal is essential. Generally, the clock signal is generated by the oscillator, and the relaxation oscillator is the most widely used oscillator. It has a simple structure, low cost, and easy integration. , and the power consumption is relatively small. [0003] Controllable relaxation oscillators are extremely useful circuits, especially in applications such as modulation and demodulation, clock recovery in data storage systems, etc. For modulation and demodulation, in order to reduce distortion, the oscillator frequency-control current is required to have a high linearity, and maximizing the oscillator frequency also requires the oscillator frequency-control current to have good control linearity. In clock recovery circuits, small jitt...

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Problems solved by technology

[0028] Figure 4 The current-controlled relaxation oscillator with dual ground timing capacitors shown has deficiencies while reducing the delay. For example, there are process deviations in the manufacturing process of capacitors C1 and C2, resulting in two capacitors whose capacitances are not equal. , Therefore, th...

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