oscillator system

Abstract

An oscillator system, comprising: an operational amplifier, working in the subthreshold region, two input terminals respectively connected to the first terminal of the reference resistor and the first terminal of the switched capacitor circuit, the output terminal outputs the first voltage, the reference resistor and the switch Each capacitor circuit is connected with a reference current; the positive end of the first capacitor is connected to the output end of the operational amplifier, and the negative end is grounded; the periodic signal module converts the DC component of the first voltage into a periodic signal, and outputs the second capacitor after the periodic signal is halved. A periodic signal; the second periodic signal after the periodic signal is halved is converted into a pair of anti-phase non-overlapping third periodic signal and fourth periodic signal; a switched capacitor circuit includes a second capacitor, according to the third periodic signal and the fourth periodic signal The fourth period signal controls charging and discharging of the second capacitor. Among them, the operational amplifier, the periodic signal module and the switched capacitor circuit form a negative feedback loop to ensure the stability of the output frequency, and the operational amplifier works in the sub-threshold region, and the power consumption of the oscillator system is extremely low.

Description

technical field [0001] The invention relates to the field of integrated circuit design, in particular to an oscillator system. Background technique [0002] In the ultra-low power consumption micro control unit MCU chip, a clock with low power consumption, high power supply voltage and temperature stability is usually required to realize the timing function required by the system. [0003] Conventional RC oscillator circuits such as figure 1 As shown, including: comparator, current source, pulse generating circuit, clock generating circuit, reference resistor, capacitor and switch. One current flows through the reference resistor to generate a reference voltage Vref, which is connected to the negative phase terminal of the comparator, and the other current charges the capacitor to generate a voltage Vc. The positive terminal of the capacitor is connected to the positive phase terminal of the comparator, and the negative terminal is grounded. The traditional RC oscillator c...

AI Technical Summary

Problems solved by technology

[0004] The above RC oscillator uses a comparator structure, so it consumes a lot of power. In addition, the delay time of the comparator and pulse generating circuit is greatly affected by temperature, so the overall output frequency is greatly affected by temperature.

Images