Resistance capacitance type relaxation oscillator employing half-period pre-charge compensation technology

Abstract

The invention relates to a resistance capacitance type relaxation oscillator employing a half-period pre-charge compensation technology. Pre-charge is carried out in the half idle period in each period by use of a timing capacitor so as to compensate time delay td generated by comparators and a latch register. The resistance capacitance type relaxation oscillator comprises one reference voltage generation circuit, two timing capacitor charge and discharge circuits, two reference voltage switching circuits, the two comparators, the SR latch register, one charge and discharge control logic generation circuit and two output buffers. According to the invention, in the first oscillation period after the rising edge of an oscillator control signal arrives, the oscillator frequency is 1/(2RC+td), and from the second period, the oscillation frequency is frequency 1/(2RC) with the time delay td eliminated. According to the invention, errors introduced in an oscillator period by the time delay td generated by the comparators and the SR latch register are eliminated fundamentally, and the frequency precision of the oscillator is improved.

Description

technical field [0001] The invention relates to a resistance-capacitance relaxation oscillator, in particular to a resistance-capacitance relaxation oscillator adopting half-period precharge compensation technology, which belongs to the field of integrated circuit design. Background technique [0002] The resistance-capacitance relaxation oscillator has the advantages of fast startup, low power consumption, low cost, and on-chip integration in CMOS technology, and can be widely used in clock generation circuits in ultra-low power consumption scenarios, such as wireless sensor network nodes. Timing wake-up circuit, etc. [0003] A resistor-capacitor relaxation oscillator (Relaxation Oscillator) is a circuit that uses RC oscillation to generate a periodic square wave. Its basic principle is to periodically charge and discharge a capacitor to generate a periodic oscillator output. Such as figure 1 As shown, a complete traditional resistance-capacitance relaxation oscillator i...

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Problems solved by technology

However, this will lead to a sharp increase in the power consumption of the comparator and the SR latch, thereby increasing the power consumption of the entire oscillator. This solution is not suitable for the application requirements of ultra-low power consumption; in addition, this solution is based on the principle can not completely eliminate the delay time t d Effect on Oscillator Frequency

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