Stmicroelectronics S.r.l.

Calogero Marco Ippolito

Michele Vaiana

Mario Chiricosta

Angelo Recchia

Pierpaolo Lombardo

Mario Maiore

Antonio Cicero

Paolo Pesenti

Sebastiano Conti

Giuseppe Bruno

Daniele Casella

Orlando Peluso

An electronic amplification-interface circuit includes a differential-current reading circuit having a first input terminal and a second input terminal. The differential-current reading circuit includes a continuous-time sigma-delta conversion circuit formed by an integrator-and-adder module generating an output signal that is coupled to an input of a multilevel-quantizer circuit configured to output a multilevel quantized signal. The integrator-and-adder module includes a differential current-integrator circuit configured to output a voltage proportional to an integral of a difference between currents received at the first and second input terminals. A digital-to-analog converter, driven by a respective reference current, receives and converts the multilevel quantized signal into a differential analog feedback signal. The integrator-and-adder module adds the differential analog feedback signal to the differential signal formed at the first and second input terminals.

Amplification interface, and corresponding measurement system and method for operating an amplification interface

A circuit includes a first input terminal, a second input terminal, a third input terminal and an output terminal. A first summation node adds signals at the first and third input terminals. A second summation node subtracts signals at the second and third input terminals. A selector selects between the added signals and subtracted signals in response to a selection signal. The output of the selector is integrated to generate an integrated signal. The integrated signal is compared by a comparator to a threshold, the comparator generating an output signal at the output terminal having a first level and a second level. Feedback of the output signal produces the selection signal causing the selector to select the added signals in response to the first level of the output signal and causing the selector to select the subtracted signals in response to the second level of the output signal.

Signal processing circuit, corresponding sensor device and apparatus

An amplification interface includes first and second differential input terminals, first and second differential output terminals providing first and second output voltages defining a differential output signal, and first and second analog integrators coupled between the first and second differential input terminals and the first and second differential output terminals, the first and second analog integrators being resettable by a reset signal. A control circuit generates the reset signal such that the first and second analog integrators are periodically reset during a reset interval and activated during a measurement interval, receives a control signal indicative of offsets in the measurement sensor current and the reference sensor current, and generates a drive signal as a function of the control signal. First and second current generators coupled first and second compensation circuits to the first and second differential input terminals as a function of a drive signal.

Amplification interface, and corresponding measurement system and method for calibrating an amplification interface

A thermally-isolated-metal-oxide-semiconducting (TMOS) sensor has inputs coupled to first and second nodes to receive first and second bias currents, and an output coupled to a third node. A tail has a first conduction terminal coupled to the third node and a second conduction terminal coupled to a reference voltage. A control circuit applies a control signal to a control terminal of the tail transistor based upon voltages at the first and second nodes so that a common mode voltage at the first and second nodes is equal to a reference common mode voltage. A differential current integrator has a first input terminal coupled to the second node and a second input terminal coupled to the first node, and provides an output voltage indicative of an integral of a difference between a first output current at the first input terminal and a second output current at the second input terminal.

A touchscreen resistive sensor includes a network of resistive sensor branches coupled to a number of sensor nodes arranged at touch locations of the touchscreen. A test sequence is performed by sequentially applying to each sensor node a reference voltage level, jointly coupling to a common line the other nodes, sensing a voltage value at the common line, and declaring a short circuit condition as a result of the voltage value sensed at the common line reaching a short circuit threshold. A current value level flowing at the sensor node to which the reference voltage level is applied is sensed and a malfunction of the resistive sensor branch coupled with the sensor node to which a reference voltage level is applied is generated as a result of the current value sensed at the sensor node reaching an upper threshold or lower threshold.

Self-test method, corresponding circuit and device

A converter circuit includes an analog-to-digital signal conversion path. An input port receives an analog input signal having an offset, and an output port delivers a digital output signal quantized over M levels. The digital output signal is sensed by a digital-to-analog feedback path, which includes a digital-to-analog converter applying to the input port an analog feedback signal produced as a function of an M-bit digital word under control of a two-state signal having alternating first and second states. M-bit digital word generation circuitry coupled to the digital-to-analog converter and sensitive to the two-state signal produces, alternately, during the first states, a first M-bit digital word, which is a function of the digital output signal quantized over M levels, and, during the second states, a second M-bit digital word, which is a function a correction value of the offset in the analog input signal.

Converter circuit, corresponding device and offset compensation method

An amplification interface includes an input terminal receiving a sensor current and an output terminal supplying an output voltage. An analog integrator is connected to the input terminal and supplies the output voltage. A current generator is connected to the input of the analog integrator and generates a compensation current based on a drive signal. A control circuit generates the drive signal for the current generator based on a control signal representing an offset in the sensor current supplied by the sensor. The current generator generates, based on the driving signal, a positive or negative current. The control circuit determines a first duration and a second duration as a function of the control signal representing the offset in the sensor current, during the measurement interval, and sets the driving signal to a first logic value for the first duration and to a second logic value for the second duration.

An amplification interface includes a drain of a first FET connected to a first node, a drain of a second FET connected to a second node, and sources of the first and second FETs connected to a third node. First and second bias-current generators are connected to the first and second nodes. A third FET is connected between the third node and a reference voltage. A regulation circuit drives the gate of the third FET to regulate the common mode of the voltage at the first node and the voltage at the second node to a desired value. A current generator applies a correction current to the first and/or second node. A differential current integrator has a first and second inputs connected to the second and first nodes. The integrator supplies a voltage representing the integral of the difference between the currents received at the second and first inputs.

A circuit for generating a bandgap voltage includes a circuit module for generation of a base-emitter voltage difference formed by a pair of PNP bipolar substrate transistors which identify a first current path and a second current path. A first current mirror of an n type is connected between the first and second branches and is further connected via a resistance for adjustment of the bandgap voltage to the second bipolar transistor. A second current mirror of a p type is connected between the first and second branches, and connected so that the current mirrors repeat current of each other. In operation to generate the bandgap voltage, current flows from the supply voltage to ground only through said the first and second bipolar substrate transistors.

Circuit arrangement for the generation of a bandgap reference voltage

A circuit includes a first current source configured to produce a first current in a first current line through a first diode-connected transistor having a voltage drop across the first diode-connected transistor, the first current being proportional to an absolute temperature via a first proportionality factor; a second current source configured to produce a second current in a second current line through a second diode-connected transistor having a voltage drop across the second diode-connected transistor, the second current being proportional to the absolute temperature via a second proportionality factor; a third current source configured to produce a third current in a third current line through a third diode-connected transistor having a voltage drop across the third diode-connected transistor; and a processing network including a sigma-delta analog-to-digital converter, the processing network being coupled to the, the second, and the third diode-connected transistors.

Sensor circuit, corresponding system and method

An embodiment circuit includes a charge pump configured to receive an input voltage at an input terminal, and a clock signal at a clock input, the charge pump being further configured to produce a first output voltage that is a multiple of the input voltage by a factor N. The circuit further includes an input stage including a reference terminal configured to receive a reference voltage, and an output terminal configured to provide the input voltage to the charge pump. The circuit also includes a capacitive element coupled to the charge pump and chargeable to a second output voltage, and a feedback network including a first feedback loop configured to feed back the first output voltage to an input of the input stage, and a second feedback loop configured to maintain a fixed offset between the first output voltage and the second output voltage.

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Aci Castello, Italy

Calogero Marco Ippolito