Patent classifications
H03M1/00
METHODS AND APPARATUS OF CHARGE-SHARING LOCKING WITH DIGITAL CONTROLLED OSCILLATORS
An integrated circuit device includes a digitally controlled oscillator (DCO), two charge-sharing capacitors, two charge-sharing switches, two pre-charge switches, and two DACs. The DCO has a first inverter and a second inverter. A first charge-sharing capacitor has a first terminal coupled to an input terminal of the first inverter through a first charge-sharing switch. A first DAC has an output terminal coupled to the first terminal of the first charge-sharing capacitor through a first pre-charge switch. A second charge-sharing capacitor has a first terminal coupled to an input terminal or an output terminal of the second inverter through a second charge-sharing switch. A second DAC has an output terminal coupled to the first terminal of the second charge-sharing capacitor through a second pre-charge switch.
Variable resolution digital equalization
A receiver includes a variable resolution analog-to-digital converter (ADC) and variable resolution processing logic/circuitry. The processing logic may use feed-forward equalization (FFE) techniques to process the outputs from the ADC. When receiving data from a channel having low attenuation, distortion, and/or noise, the ADC and processing logic may be configured to sample and process the received signal using fewer bits, and therefore less logic, than when configured to receiving data from a channel having a higher attenuation, distortion, and/or noise. Thus, the number of (valid) bits output by the ADC, and subsequently processed (e.g., for FFE equalization) can be reduced when a receiver of this type is coupled to a low loss channel. These reductions can reduce power consumption when compared to operating the receiver using the full (i.e., maximum) number of bits the ADC and processing logic is capable of processing.
METHOD AND SYSTEM FOR ASYNCHRONOUS SUCCESSIVE APPROXIMATION REGISTER (SAR) ANALOG-TO-DIGITAL CONVERTERS (ADCS)
An asynchronous successive approximation register analog-to-digital converter (SAR ADC), which utilizes one or more overlapping redundant bits in each digital-to-analog converter (DAC) code word, is operable to generate an indication signal that indicates completion of each comparison step and indicates that an output decision for each comparison step is valid. A timer may be initiated based on the generated indication signal. A timeout signal may be generated that preempts the indication signal and forces a preemptive decision, where the preemptive decision sets one or more remaining bits up to, but not including, the one or more overlapping redundant bits in a corresponding digital-to-analog converter code word for a current comparison step to a particular value. For example, the one or more remaining bits may be set to a value that is derived from a value of a bit that was determined in an immediately preceding decision.
Analog-to-digital converter and clock generation circuit thereof
An analog-to-digital converter and a clock generation circuit thereof are provided. The clock generation circuit comprises cascaded clock generation modules. The clock generation module at each stage is configured to generate a corresponding internal clock signal, and each stage of the clock generation module comprises a delay module and a logic gate module. The second input end of the N-th stage of the logic gate module is connected to the output end of the previous stage of the logic gate module, and the output end of the logic gate module is configured to output an internal clock, so that each stage of the clock generation module can generate one internal clock signal.
High Resolution Analog to Digital Converter (ADC) with Improved Bandwidth
A high resolution analog to digital converter (ADC) with improved bandwidth senses an analog signal (e.g., a load current) to generate a digital signal. The ADC operates based on a load voltage produced based on charging of an element (e.g., a capacitor) by a load current and a digital to analog converter (DAC) output current (e.g., from a N-bit DAC). The ADC generates a digital output signal representative of a difference between the load voltage and a reference voltage. This digital output signal is used directly, or after digital signal processing, to operate an N-bit DAC to generate a DAC output current that tracks the load current. In addition, quantization noise is subtracted from the digital output signal thereby extending the operational bandwidth of the ADC. In certain examples, the operational bandwidth of the ADC extends up to 100s of kHz (e.g., 200-300 kHz), or even higher.
High efficiency current source/sink DAC
A current source and/or current sink digital-to-analog converter (DAC) includes a DAC circuit that converts a digital code to an analog current or voltage signal, an optional transconductance circuit that converts a voltage output of the DAC circuit into a current signal, and an output circuit that amplifies a current output of the DAC circuit or optionally amplifies a current output of the transconductance circuit to set a desired high current output for application to an output of the current source and/or current sink DAC. A power supply control current may be coupled to a power supply circuit that supplies power to the output circuit of the current source and/or current sink DAC. The power supply control current adjusts the output of the power supply circuit to cause the current source and/or current sink DAC to operate at a higher power efficiency.
Time-domain incremental two-step capacitance-to-digital converter
An exemplary incremental two-step capacitance-to-digital converter (CDC) with a time-domain sigma-delta modulator (TDΔΣM) includes a voltage-controlled oscillator (VCO)-based integrator that can be used in a low-order loop configuration. Example prototypes are disclosed, which when fabricated in 40-nm CMOS technology, provides CDC resolution of 0.29 fF while dissipating only 0.083 nJ per conversion.
Linearized optical digital-to-analog modulator
In a system for converting digital data into a modulated optical signal, an electrically controllable device, including a modulator having one or more actuating electrodes, provides an analog-modulated optical signal that is modulated in response to output data bits of a digital-to-digital mapping. A digital-to-digital conversion provides the mapping of input data words to the output data bits. The mapping enables adjustments to correct for non-linearities and other undesirable characteristics, thereby improving signal quality.
Transition aware dynamic element matching
A system includes a digital-to-analog converter comprising a plurality of unit elements, and a dynamic element matching encoder coupled to the digital-to-analog converter. The dynamic element matching encoder includes a circuit configured to determine a number of unit elements of a digital-to-analog converter to be transitioned (N.sub.tm), determine a first number of unit elements to be turned on, and determine a second number of unit elements to be turned off. The circuit may further generate a first signal identifying individual unit elements of one or more unit elements of the digital-to-analog converter in the off state to be turned on, and a second signal identifying the individual unit elements of one or more unit elements of the digital-to-analog converter in the on state to be turned off.
Data reduction techniques in a LIDAR system
Techniques to adjust a gain of an analog-to-digital converter circuit (ADC) and/or an ADC full scale from one sample to the next of an analog input signal to compensate for the signal loss over distance, which can increase an effective dynamic range of the system. The benefit of compensating for the signal loss due to distance is that a data interface between the ADC of the receiver of the LIDAR system and a signal processor no longer needs to support the dynamic range from the range specification.