公开(公告)号：US09602084B2

公开(公告)日：2017-03-21

申请号：US14966616

申请日：2015-12-11

Applicant: TEXAS INSTRUMENTS INCORPORATED

Inventor： Subramanian Jagdish Narayan ,  Dipankar Mandal ,  Janakiraman Seetharaman ,  Kiran Godbole

IPC: G01R23/02 ,  H03K3/037 ,  G01R19/165

CPC classification number: H03K3/037 ,  G01R19/1659 ,  H03K3/0231

Abstract: Frequency detector and oscillator circuits are disclosed. Example frequency detector and oscillator circuits disclosed herein include a current approximation circuit coupled to an external clock operating at a target frequency. In some examples, the current approximation circuit is configured to determine a magnitude of a first current to charge a capacitor to reach a reference voltage during a first set of clock cycles generated by the external clock. In some examples, the current approximation circuit is further configured to generate an output current based on the magnitude of the first current and to use the output current to produce a comparator output. In some examples, the frequency detector and oscillator circuits further include a latching circuit coupled to receive the comparator output from the current approximation circuit. In some such examples, the latching circuit is configured to generate oscillating signals at the target frequency based on the comparator output.

公开(公告)号：US20160308516A1

公开(公告)日：2016-10-20

申请号：US14966616

申请日：2015-12-11

Applicant: TEXAS INSTRUMENTS INCORPORATED

Inventor： Subramanian Jagdish Narayan ,  Dipankar Mandal ,  Janakiraman Seetharaman ,  Kiran Godbole

IPC: H03K3/037 ,  G01R19/165

CPC classification number: H03K3/037 ,  G01R19/1659 ,  H03K3/0231

Abstract: Frequency detector and oscillator circuits are disclosed. Example frequency detector and oscillator circuits disclosed herein include a current approximation circuit coupled to an external clock operating at a target frequency. In some examples, the current approximation circuit is configured to determine a magnitude of a first current to charge a capacitor to reach a reference voltage during a first set of clock cycles generated by the external clock. In some examples, the current approximation circuit is further configured to generate an output current based on the magnitude of the first current and to use the output current to produce a comparator output. In some examples, the frequency detector and oscillator circuits further include a latching circuit coupled to receive the comparator output from the current approximation circuit. In some such examples, the latching circuit is configured to generate oscillating signals at the target frequency based on the comparator output.

Abstract translation: 公开了频率检测器和振荡器电路。 本文公开的示例性频率检测器和振荡器电路包括耦合到以目标频率工作的外部时钟的电流近似电路。 在一些示例中，电流近似电路被配置为在由外部时钟产生的第一组时钟周期期间确定用于对电容器充电以达到参考电压的第一电流的幅度。 在一些示例中，电流近似电路还被配置为基于第一电流的幅度产生输出电流并且使用输出电流来产生比较器输出。 在一些示例中，频率检测器和振荡器电路还包括耦合以从电流近似电路接收比较器输出的锁存电路。 在一些这样的示例中，锁存电路被配置为基于比较器输出以目标频率产生振荡信号。