A calibratable switched-capacitor voltage reference and an associated calibration method are described. The voltage reference includes dynamic diode elements providing diode voltages, input capacitor(s) for sampling input voltages, base-emitter capacitor(s) for sampling one diode voltage with respect to a ground, dynamically trimmable capacitor(s) for sampling the one diode voltage with respect to another diode voltage, and an operational amplifier coupled to the capacitors for providing reference voltage(s) based on the sampled input and diode voltages and on trims of the trimmable capacitor(s). The voltage reference can be configured as a first integrator of a modulator stage of a delta-sigma analog-to-digital converter.

A calibratable switched-capacitor voltage reference and an associated calibration method are described. The voltage reference includes dynamic diode elements providing diode voltages, input capacitor(s) for sampling input voltages, base-emitter capacitor(s) for sampling one diode voltage with respect to a ground, dynamically trimmable capacitor(s) for sampling the one diode voltage with respect to another diode voltage, and an operational amplifier coupled to the capacitors for providing reference voltage(s) based on the sampled input and diode voltages and on trims of the trimmable capacitor(s). The voltage reference can be configured as a first integrator of a modulator stage of a delta-sigma analog-to-digital converter.

An analog to digital converter (ADC) includes voltage and reference input terminals, a buffer circuit, and control logic. The buffer circuit includes input and output terminals and a variable resistor including resistive branches connected in parallel. The control logic is configured to, in a calibration phase, determine a given gain value for which gain error is to be calibrated, determine a set of the resistive branches in the buffer circuit to be used to achieve the given gain value, successively enable a different resistive branch of the variable resistor of the set until all resistive branches of the set have been enabled, determine an output code resulting after enabling all resistive branches of the set, and, from the output code, determine a gain error of the given gain value. The control logic is further configured to take corrective action based upon the gain error of the given gain value.

An analog to digital converter (ADC) circuit includes voltage and reference input terminals, a sample circuit, and control logic. The sample circuit includes input and output terminals, and capacitors connected in parallel and arranged between the input and output terminals. The control logic is configured to, in a calibration phase of operation, cause the multiplexer to route the ADC reference input terminal to the sampling voltage input terminal, determine a given gain value, determine a set of the capacitors to be used to achieve the given gain value, successively enable capacitor subsets to sample voltage of the reference input while disabling a remainder of the capacitors until all capacitors have been enabled, determine a resulting output code, and from the output code, determine a gain error of the given gain value of the ADC circuit.

A calibratable switched-capacitor voltage reference and an associated calibration method are described. The voltage reference includes dynamic diode elements providing diode voltages, input capacitor(s) for sampling input voltages, base-emitter capacitor(s) for sampling one diode voltage with respect to a ground, dynamically trimmable capacitor(s) for sampling the one diode voltage with respect to another diode voltage, and an operational amplifier coupled to the capacitors for providing reference voltage(s) based on the sampled input and diode voltages and on trims of the trimmable capacitor(s). The voltage reference can be configured as a first integrator of a modulator stage of a delta-sigma analog-to-digital converter.

A DAC error measurement apparatus includes: an ADC and a feedback DAC, where a measurement input of the ADC includes a square wave signal with a constant frequency, a direct-current signal at a constant logical level, and an analog output of the feedback DAC; a measurement selection module, configured to provide a measured digit in a digital output to a separately selected source cell, and provide remaining digits in the digital output to remaining source cells, where the measured digit is a flippable digit, and the remaining digits are non-flipping digits; and a measurement module, configured to measure an amplitude of the digital output based on the digital output. One flipping digit in the digital output is the measured digit, and the remaining digits are the non-flipping digits, such that the measurement selection module may separately select one source cell to receive the measured digit.

A correction method and a correction circuit for a sigma-delta modulator (SDM) are provided. The SDM includes a loop filter, a quantizer, and a digital-to-analog converter (DAC). The correction method includes the following steps: controlling the DAC not to receive the output of the quantizer; controlling the SDM to stop receiving signals; inputting a test signal to the DAC; converting the output of the loop filter to a digital signal; comparing the digital signal with a preset value; and adjusting the loop filter according to the result of comparing the digital signal and the preset value.

A correction method and a correction circuit for a sigma-delta modulator (SDM) are disclosed. The SDM includes a loop filter, a quantizer, and a digital-to-analog converter (DAC), and the loop filter includes a resonator. The correction circuit includes a memory and a control circuit. The memory stores multiple program instructions. The control circuit executes the program instructions to correct the SDM. The correction procedure of the SDM includes the following steps: inputting a test signal to the SDM; obtaining a signal characteristic value of an output signal of the SDM; and adjusting the resonator according to the signal characteristic value.

A correction method and a correction circuit for a sigma-delta modulator (SDM) are provided. The SDM includes a loop filter, a quantizer, and a digital-to-analog converter (DAC). The correction method includes: generating a test signal for a frequency to be tested; inputting the test signal to a feedforward circuit that includes at least one adjustable impedance circuit, the test signal being inputted to the SDM through the impedance circuit; calculating an output signal of the SDM to obtain a value of a signal transfer function (STF) of the SDM at the frequency to be tested; and adjusting the impedance circuit.

A correction method and a correction circuit for a sigma-delta modulator (SDM) are provided. The SDM includes a loop filter, a quantizer, and a digital-to-analog converter (DAC). The correction method includes: generating a test signal for a frequency to be tested; inputting the test signal to a feedforward circuit that includes at least one adjustable impedance circuit, the test signal being inputted to the SDM through the impedance circuit; calculating an output signal of the SDM to obtain a value of a signal transfer function (STF) of the SDM at the frequency to be tested; and adjusting the impedance circuit.