公开(公告)号：US11742834B2

公开(公告)日：2023-08-29

申请号：US17931867

申请日：2022-09-13

Applicant: NXP B.V.

Inventor： Sander Derksen ,  Jos Verlinden ,  Ids Christiaan Keekstra ,  René Verlinden

IPC: H03K3/0231 ,  H03K3/011

CPC classification number: H03K3/011 ,  H03K3/0231

Abstract: Various embodiments relate to a free running oscillator, that includes a switch capacitor based frequency-to-voltage converter (F2V), a comparator, and a voltage controlled oscillator (VCO), which may be collectively configured to reduce amplifier offset and flicker noise while increasing effective gain of the amplifier of the comparator. The F2V may produce a feedback voltage Vfb corresponding to frequencies of output of the VCO. The comparator may be configured to sample a reference voltage Vref using a sampling capacitor, compare Vref to Vfb, and generate an output based on any difference between Vref and Vfb, where the output may be integrated using an integrating capacitor of the comparator. The comparator may compensate for parasitic capacitance at the output of the amplifier by using an amplifier having two outputs, with the sampling capacitor and integrating capacitor being coupled to respectively different outputs of the amplifier.

公开(公告)号：US20230006655A1

公开(公告)日：2023-01-05

申请号：US17931867

申请日：2022-09-13

Applicant: NXP B.V.

Inventor： Sander Derksen ,  Jos Verlinden ,  Ids Christiaan Keekstra ,  René Verlinden

IPC: H03K3/011 ,  H03K3/0231

Abstract: Various embodiments relate to a free running oscillator, that includes a switch capacitor based frequency-to-voltage converter (F2V), a comparator, and a voltage controlled oscillator (VCO), which may be collectively configured to reduce amplifier offset and flicker noise while increasing effective gain of the amplifier of the comparator. The F2V may produce a feedback voltage Vfb corresponding to frequencies of output of the VCO. The comparator may be configured to sample a reference voltage Vref using a sampling capacitor, compare Vref to Vfb, and generate an output based on any difference between Vref and Vfb, where the output may be integrated using an integrating capacitor of the comparator. The comparator may compensate for parasitic capacitance at the output of the amplifier by using an amplifier having two outputs, with the sampling capacitor and integrating capacitor being coupled to respectively different outputs of the amplifier.