On chip test architecture for continuous time delta sigma analog-to-digital converter
AssigneeSTMicroelectronics International N.V.
InventorsAnkur Bal, Abhishek Jain, Sharad Gupta
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Abstract
An integrated circuit includes a continuous time delta sigma analog-to-digital converter (CTDS ADC) and a test circuit for testing the CTDS ADC. The test circuit converts multi-bit digital reference data to a single-bit digital stream. The test circuit then passes the single-bit digital stream to a finite impulse response digital-to-analog converter (FIR DAC). The FIR DAC converts the single-bit digital stream to an analog test signal. The analog test signal is then passed to the CTDS ADC. The CTDS ADC converts the analog test signal to digital test data. The test circuit analyzes the digital test data to determine the accuracy of the CTDS ADC.
Claims22
An integrated circuit, comprising:
- a test circuit including:
- a first memory configured to store digital reference data representing an analog reference signal;
- a modulator configured to receive the digital reference data and to convert the digital reference data to single-bit data stream;
- a second memory configured to receive the single-bit data stream from the modulator and to store the single-bit data stream;
- and
- a finite-impulse response filter configured to receive the single-bit data stream from the second memory and to convert the single-bit data stream to an analog test signal;
- and
- a continuous time delta sigma analog-to-digital converter coupled to the test circuit and including:
- an input configured to receive the analog test signal from the test circuit;
- conversion circuit configured to convert the analog test signal to digital test data;
- and
- an output configured to output the digital test data, wherein the test circuit is configured to receive the digital test data from the continuous time delta sigma analog-to-digital converter and to assess a performance of the continuous time delta sigma analog-to-digital converter based on the digital test data.
A method, comprising:
- storing, in an integrated circuit, digital reference data corresponding to a digital representation of an analog reference signal;
- converting the digital reference data to a single-bit data stream;
- converting, with a finite impulse response digital-to-analog converter of the integrated circuit, the single-bit data stream to an analog test signal;
- and
- converting, with a continuous time delta sigma analog-to-digital converter of the integrated circuit, the analog test signal to digital test data;
- and
- determining an accuracy of the digital test data with a test circuit of the integrated circuit, wherein determining the accuracy includes processing the digital test data with a digital signal processor of the test circuit.
A method, comprising:
- storing digital reference data in an integrated circuit, the digital reference data corresponding to an over-sampled X-bit representation of an analog reference signal;
- generating, from the digital reference data, a single-bit data stream;
- storing the single-bit data stream in a memory;
- passing the single-bit data stream from the memory to a finite-impulse response digital-to-analog converter including a plurality of flip-flops coupled in series, a plurality of single-bit digital-to-analog converters each coupled to an output of a respective flip-flop, and a plurality of summers;
- generating an analog test signal with the finite-impulse response digital-to-analog converter by summing outputs of the single-bit digital-to-analog converters with the summers;
- converting the analog test signal to digital test data with a Y-bit continuous time delta-sigma analog-to-digital converter of the integrated circuit, wherein Y is an integer less than or equal to X;
- and
- determining an accuracy of the continuous time delta-sigma analog-to-digital converter by comparing the digital test data to the digital reference data.
Dependencies are inferred from the claim text.