Fast oscillation starting crystal oscillator driving circuit and integrated circuit

Abstract

The invention discloses a fast oscillation starting crystal oscillator driving circuit including a first series unit comprising a first resistor, a first inductor and a first capacitor; a second capacitor, an adjustable resistor unit and a phase inverter that are connected with the first series unit in parallel; a first grounding capacitor which is connected with the input end of the phase inverter; a second grounding capacitor which is connected with the output end of the phase inverter; a controller which is used for controlling the equivalent resistance value of the adjustable resistor unit according to an input end signal of the phase inverter. According to the invention, the controller adjusts the resistance value of the adjustable resistor unit according to the received information, so that different requirements of the equivalent resistor connected in parallel with the inverter in different states of the rapid oscillation starting crystal oscillator drive circuit can be met; therefore, the effects of rapid oscillation starting, no increase of the oscillation amplitude and no damage to the service life are realized in the same rapid oscillation starting crystal oscillator drive circuit. Correspondingly, the invention also discloses an integrated circuit with the same beneficial effects.

Description

technical field [0001] The invention relates to the field of crystal oscillator circuit design, in particular to a fast start-up crystal oscillator drive circuit and an integrated circuit. Background technique [0002] Currently, conventional crystal oscillator models such as Figure 1a As shown, including inductance Ls, capacitance Cs, resistance Rs and package capacitance Cp, its intrinsic resonant frequency is: [0003] [0004] Considering the existence of package capacitance Cp, its resonant frequency is: [0005] [0006] Due to the existence of the resistor Rs, the resonant network cannot maintain oscillation, and an external negative resistance is needed to offset the consumption of the resistor Rs. Such as Figure 1b As shown, a negative resistance is formed by an inverter and capacitors C01 and C02 to provide energy for the crystal oscillator model, while resistor R01 provides a bias voltage for the inverter. Figure 1b The small-signal model of Figure 2...

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Problems solved by technology

[0017] due to r o It is very large, so increasing the resistance value of R01 can increase the signal gain. The larger the resistance R01, the greater the signal gain, and the faster the oscillation speed of the circuit. At the same time, as the gain increases, the oscillation amplitude of the circuit also increases. As a result, the life of the crystal oscillator model is shortened, and the existing crystal oscillator model cannot achieve the two effects of fast start-up speed and no impact on circuit life at the same time

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