The present invention provides a fractional-N frequency synthesizer comprising a divider controller comprising a multistage noise Shaping (MASH) digital delta-sigma modulator comprising L stages, wherein the jth stage is configured to receive as an input the sum of the error of the preceding stage and a high amplitude dither signal derived from the error of the kth stage, where 1≤j≤k≤L.

A circuit includes a transconductance stage having first and second outputs. The circuit also includes a comparator having first and second inputs. The first input is coupled to the first output, and the second input is coupled to the second output. The comparator includes first through fifth transistors and a pair of cross-coupled transistors. The pair of cross-coupled transistors is coupled to the second current terminals of the first and second transistors. The second current terminal of the third transistor is coupled to the second current terminal of the first transistor, and the first current terminals of the first, second, and third transistors are coupled together. The second current terminals of the fourth and fifth transistors are coupled together and to the control input of the third transistor.

An A/D converter includes an A/D conversion unit and an output unit. The A/D conversion unit includes a second A/D converter (successive approximation register A/D converter) and generates first digital data having a first number of bits and second digital data having a second number of bits, where the second number of bits is smaller than the first number of bits. The output unit provides first output information that is the first digital data and also provides second output information based on the second digital data. The output unit provides the second output information before providing the first output information.

A digital filter is used in an A/D converter and includes a first filter and second filter. The first filter outputs first digital data by performing filter processing on output of an A/D conversion unit included in the A/D converter. The second filter outputs second digital data by performing filter processing on the output of the A/D conversion unit. The second digital data has either a lower resolution or a smaller effective number of bits than the first digital data does. The second filter outputs the second digital data before the first filter outputs the first digital data.

A variety of methods, controllers and electric machine systems are described that facilitate pulsed control of electric machines (e.g., electric motors and generators) to improve the machine's energy conversion efficiency. Under selected operating conditions, the electric machine is intermittently driven (pulsed). The pulsed operation causes the output of the electric machine to alternate between a first output level and a second output level that is lower than the first output level. The output levels are selected such that at least one of the electric machine and a system that includes the electric machine has a higher energy conversion efficiency during the pulsed operation than the electric machine would have when operated at a third output level that would be required to drive the electric machine in a continuous manner to deliver the desired output. In some embodiments, the second output level is zero torque.

An analog-to-digital converter includes: a sample/hold circuit, which samples an analog signal, and outputs a first voltage; a digital-to-analog conversion circuit, which converts a digital signal to output a second voltage; an amplifier, which amplifies the first voltage and the second voltage; a noise shaping filter, which integrates a residual voltage corresponding to a difference between the amplified first voltage and the amplified second voltage, and generates a first integration voltage and a second integration voltage; a comparator, which compares a sum of the amplified first voltage, the first integration voltage, and the second integration voltage with the amplified second voltage; and a SAR logic, which outputs the digital signal according to a comparison result of the comparator, and controls the digital-to-analog conversion circuit.

An analog-to-digital converter (ADC) includes a modulator, an integrator circuit, and first and second differentiator circuits. The modulator has a modulator input and a modulator output. The modulator input is configured to receive an analog signal, and the modulator is configured to generate digital data on the modulator output. The integrator circuit has an integrator circuit input and an integrator output. The integrator input is coupled to the modulator output. The first differentiator circuit is coupled to the integrator output, and the first differentiator circuit is configured to be clocked with a first clock. The second differentiator circuit is coupled to the integrator output, and the second differentiator circuit configured to be clocked with a second clock. The second clock is out of phase with respect to the first clock.

A photoelectric converter comprising a pixel unit and a processor configured to process a pixel signal output from the pixel unit is provided. The processor comprises a ΔΣ AD converter configured to convert the pixel signal into a digital signal. The ΔΣ AD converter comprises a subtracter to which the pixel signal and a subtraction signal are input, an integrator configured to receive an output from the subtracter, a comparator configured to compare an output from the integrator with a predetermined voltage, a decimation filter configured to generate the digital signal based on an output from the comparator, a delay unit configured to delay an output from the comparator, a buffer configured to buffer an output from the delay unit, and a DA converter configured to convert an output from the buffer into an analog signal to generate the subtraction signal.

A photoelectric converter comprising a pixel unit and a processor configured to process a pixel signal output from the pixel unit is provided. The processor comprises a ΔΣ AD converter configured to convert the pixel signal into a digital signal. The ΔΣ AD converter comprises a subtracter to which the pixel signal and a subtraction signal are input, an integrator configured to receive an output from the subtracter, a comparator configured to compare an output from the integrator with a predetermined voltage, a decimation filter configured to generate the digital signal based on an output from the comparator, a delay unit configured to delay an output from the comparator, a buffer configured to buffer an output from the delay unit, and a DA converter configured to convert an output from the buffer into an analog signal to generate the subtraction signal.

A delta-sigma modulator includes a first amplifier having an input, a feedback control input, and an output. The input is a first input of the delta-sigma modulator. The delta-sigma modulator further includes a first integrator and a first quantizer. The first integrator has an input and an output. The output of the first amplifier is coupled to the input of the first integrator. The first quantizer has an input and an output. The output of the first quantizer is coupled to the feedback control input of the first amplifier.