An analog to digital (A/D) converter includes a capacitor array having respective first terminals selectively coupled to a reference voltage or ground via a plurality of switches and having respective second terminals coupled to a sample and hold (S/H) output. The A/D converter also includes a voltage comparator having a first input coupled to the S/H output and having a second input coupled to a bias voltage. The voltage comparator is configured to output a comparison voltage responsive to a sampled charge at the S/H output and the bias voltage. The A/D converter also includes a successive approximation register coupled to receive the comparison voltage and configured to output an approximate digital code responsive to the comparison voltage, wherein the approximate digital code is varied by controlling an equivalent capacitance of the capacitor array.

A test method is provided to test a semiconductor integrated circuit including an analog-to-digital converter and/or a digital-to-analog converter. An analog test signal having a test pattern is generated using an analog test signal generator or a digital test signal having the test pattern using a digital test signal generator. An analog output signal corresponding to the test pattern is generated by applying, as a digital input signal, the digital test signal having the test pattern to a digital-to-analog converter responsive to generation of the digital test signal. A digital output signal corresponding to the test pattern is generated by applying, as an analog input signal, the analog test signal having the test pattern or the analog output signal corresponding to the test pattern to an analog-to-digital converter. A normality of the semiconductor integrated circuit is determined based on the digital output signal corresponding to the test pattern.

A safety circuit for the multi-channel processing of an input signal. The safety circuit includes an analog-to-digital conversion device having a first analog input and a second analog input and at least one digital output for processing the input signal. Furthermore, the safety circuit has a test device which is set up to apply a test signal at the first and/or second input of the A/D conversion device in such a way that the test signal superposes the input signal such that the test signal dominates the input signal.

In an embodiment, a circuit includes N sensing channels. Each channel includes a first main sensing node and a second redundancy sensing node paired therewith. N analog-to-digital converters (ADCs) are coupled to the first sensing nodes, with digital processing circuits coupled to the N ADCs. A pair of multiplexers are coupled to the second sensing nodes and to the N ADCs with a further ADC coupled to the output of the second multiplexer. An error checking circuit is coupled to the outputs of the second multiplexer and the further ADC to compare, at each time window in a sequence of N time windows, a first digital value and a second digital value resulting from conversion to digital of: an analog sensing signal at one of the first sensing nodes, and an analog sensing signal at the second sensing node paired with the selected one of the first sensing nodes.

In an embodiment, a circuit includes N sensing channels. Each channel includes a first main sensing node and a second redundancy sensing node paired therewith. N analog-to-digital converters (ADCs) are coupled to the first sensing nodes, with digital processing circuits coupled to the N ADCs. A pair of multiplexers are coupled to the second sensing nodes and to the N ADCs with a further ADC coupled to the output of the second multiplexer. An error checking circuit is coupled to the outputs of the second multiplexer and the further ADC to compare, at each time window in a sequence of N time windows, a first digital value and a second digital value resulting from conversion to digital of: an analog sensing signal at one of the first sensing nodes, and an analog sensing signal at the second sensing node paired with the selected one of the first sensing nodes.

A metastable state detection device and method, and an ADC circuit are disclosed. The metastable state detection device includes: a delay unit which is configured to receive a synchronization signal and delay the synchronization signal based on preset step delay values; a first flip-flop unit including a first clock input terminal, a first data input terminal and a first data output terminal, wherein the first clock input terminal is configured to receive a clock signal; the first data input terminal is configured to receive the delayed synchronization signal; a second flip-flop unit including a second clock input terminal, a second data input terminal and a second data output terminal; a processing module connected to the second data output terminal, which is configured to receive a target clock signal and detect a metastable state of the first flip-flop unit according to the target clock signal.

An AD converter includes a plurality of analog input terminals, a reference signal generation circuit that generates an analog reference signal, a sample-and-hold unit that includes a plurality of sample-and-hold circuits sampling the analog reference signal or one of analog input signals from the analog input terminals, a control unit that controls the sample-and-hold unit, and a conversion unit that converts an output signal from the sample-and-hold unit into a digital signal. The control unit controls the sample-and-hold unit to perform the output operation for analog input signal and the sampling operation for the analog reference signal.

A metastable state detection device and method, and an ADC circuit are disclosed. The metastable state detection device includes: a delay unit which is configured to receive a synchronization signal and delay the synchronization signal based on preset step delay values; a first flip-flop unit including a first clock input terminal, a first data input terminal and a first data output terminal, wherein the first clock input terminal is configured to receive a clock signal; the first data input terminal is configured to receive the delayed synchronization signal; a second flip-flop unit including a second clock input terminal, a second data input terminal and a second data output terminal; a processing module connected to the second data output terminal, which is configured to receive a target clock signal and detect a metastable state of the first flip-flop unit according to the target clock signal.

According to aspects of the disclosure, an apparatus is disclosed comprising: a controller; an analog-to-digital converter (ADC) coupled to the controller, the ADC including an input terminal for receiving a sensor signal from a transducer; and a diagnostic circuit coupled to the input terminal of the ADC and to the controller, the diagnostic circuit being configured to: generate a diagnostic signal that indicates whether a voltage at the input terminal of the ADC meets a first threshold, and provide the diagnostic signal to the controller, wherein the controller is configured to: receive a data sample from the ADC, detect whether the data sample meets a second threshold, and transition the apparatus into a safe state when: (i) the diagnostic signal indicates that the voltage at the input terminal does not meet the first threshold, and (ii) the data sample meets the second threshold.

A circuit arrangement includes a microcontroller having a first analog-to-digital converter whose input is connected to the output of a first multiplexer whose output is connected to a first comparison device for comparing reference voltages, and a first serial interface circuit connected to the first comparison device. A voltage generating circuit includes a second analog-to-digital converter whose input is connected to the output of a second multiplexer whose output is connected to a number of registers, which are connected to a safety value generator and store digital values together with a respective safety value, and a second serial interface circuit connected to the registers. The first and second serial interface circuits are connected to each other for communication of the microcontroller with the voltage generating circuit, the first interface circuit being connected to a second comparison device for comparing supply voltages and/or currents with desired voltages and/or desired currents.