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: 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: When converting an analog signal to N-bit digital codes, high SNR (signal to noise ratio) by generating multiple N-bit codes from the same analog sample and averaging the N-bit codes. However, the entire N-bit code is determined only a single time, and only P-bit (P less than N) codes are generated. The P-bit codes may be averaged, and the N-bit code is corrected based on the average value to generate an accurate N-bit digital code. As P can be much less than N, the correction can be implemented in a few iterations, thereby enabling the ADCs to be implemented with a high throughput performance. Due to the correction, a high SNR may be attained as well.