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公开(公告)号：US11431292B2
公开(公告)日：2022-08-30
申请号：US17451262
申请日：2021-10-18
Applicant: NXP B.V.
Inventor： Jos Verlinden , Rehan Ahmed , Reinier Hoogendoorn
Abstract: A circuit and method for starting-up a crystal oscillator is described. A crystal resonator is configured to be coupled to a start-up circuit including an H-bridge circuit having a number of switches. A plurality of switch control signals are generated in response to detecting a zero-crossing event of the motional current in the crystal resonator. The switches of the H-bridge circuit are controlled by the switch control signals to apply a voltage to the terminals of the crystal resonator in a first polarity during a first switch control phase and a second opposite polarity during a second switch control phase. During a respective first subphase of the respective switch control phase, the plurality of switches are configured in a first configuration to couple the supply node to a respective crystal resonator terminal. During a respective second subphase of the respective switch control phase the plurality of switches are configured in a second configuration to couple the supply node to the respective crystal resonator terminal. The resistance between the supply node and the respective crystal resonator terminal is larger in the second configuration than the first configuration. A zero-crossing is detected during each respective second sub-phase.
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公开(公告)号：US20220173699A1
公开(公告)日：2022-06-02
申请号：US17451262
申请日：2021-10-18
Applicant: NXP B.V.
Inventor： Jos Verlinden , Rehan Ahmed , Reinier Hoogendoorn
Abstract: A circuit and method for starting-up a crystal oscillator is described. A crystal resonator is configured to be coupled to a start-up circuit including an H-bridge circuit having a number of switches. A plurality of switch control signals are generated in response to detecting a zero-crossing event of the motional current in the crystal resonator. The switches of the H-bridge circuit are controlled by the switch control signals to apply a voltage to the terminals of the crystal resonator in a first polarity during a first switch control phase and a second opposite polarity during a second switch control phase. During a respective first subphase of the respective switch control phase, the plurality of switches are configured in a first configuration to couple the supply node to a respective crystal resonator terminal. During a respective second subphase of the respective switch control phase the plurality of switches are configured in a second configuration to couple the supply node to the respective crystal resonator terminal. The resistance between the supply node and the respective crystal resonator terminal is larger in the second configuration than the first configuration. A zero-crossing is detected during each respective second sub-phase.
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公开(公告)号：US08922288B2
公开(公告)日：2014-12-30
申请号：US13774163
申请日：2013-02-22
Applicant: NXP B.V.
CPC classification number: H03L5/00 , H03B5/06 , H03B5/12 , H03B5/1212 , H03B5/124 , H03B5/36 , H03L3/00
Abstract: An oscillator circuit comprising first and second resonator terminals for connecting to respective terminals of a resonator. The oscillator circuit also comprises a first inverting amplifier connected between the first and second resonator terminals in a first mode of operation; and a back to back pair of second inverting amplifiers connected between the first and second resonator terminals in a second mode of operation. There is also provided a controller configured to compare an operational parameter of the oscillator circuit to a switchover threshold, and switch the oscillator circuit from the first mode of operation to the second mode of operation when the operational parameter exceeds the switchover threshold.
Abstract translation: 一种振荡器电路，包括用于连接到谐振器的各个端子的第一和第二谐振器端子。 振荡器电路还包括在第一操作模式下连接在第一和第二谐振器端子之间的第一反相放大器; 以及在第二操作模式下连接在第一和第二谐振器端子之间的背靠背对的第二反相放大器。 还提供了一种控制器，被配置为将振荡器电路的操作参数与切换阈值进行比较，并且当操作参数超过切换阈值时，将振荡器电路从第一操作模式切换到第二操作模式。
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