Sgs-Thomson Microelectronics S.r.l.

Stmicroelectronics S.r.l.

Stmicroelectronics Asia Pacific Pte Limited

Consorzio Per La Ricerca Sulla Microelettronica Nel Mezzogiorno

Giona Fucili

Maurizio Nessi

Annamaria Rossi

Alberto Gola

Marcello Leone

Lorenzo Papillo

Andrea Pasquino

Rinaldo Castello

Aldo Vittorio Novelli

Patrizia Milazzo

Marco Sautto

Agostino Mirabelli

Kaufik Linggajaya

Valerio Lo Muzzo

In accordance with an embodiment, a method of operating a piezoelectric transducer configured to transduce mechanical vibrations into transduced electrical signals at a pair of sensor electrodes includes stimulating a resonant oscillation of the piezoelectric transducer by applying at least one pulse electrical stimulation signal to the pair of sensor electrodes; detecting, at the pair of sensor electrodes, at least one electrical signal resulting from the stimulated resonant oscillation, wherein the at least one electrical signal resulting from the stimulated resonant oscillation oscillates at a resonance frequency of the piezoelectric transducer; measuring a frequency of oscillation of the at least one electrical signal resulting from the stimulated resonant oscillation to obtain a measured resonance frequency of the piezoelectric transducer; and tuning a stopband frequency of a notch filter coupled to the piezoelectric transducer to match the measured resonance frequency of the piezoelectric transducer.

Calibration method, corresponding circuit and apparatus

Many integrated circuit die are fabricated on a wafer. Each die includes integrated functional circuitry with an array of fuse elements that are visible to optical inspection. An electrical wafer sort is performed to test the integrated functional circuitry of each die. The array of fuse elements for each die on the wafer are programmed through the electrical wafer sort process with data bits defining a die identification that specifies a location of the die on the wafer. The die is then encapsulated in a package. In the event of package failure, a decapsulation is performed to access the die. Optical inspection of the array of fuse elements is then made to extract the die identification.

Die identification by optically reading selectively blowable fuse elements

A successive approximation register has a serial input and output comprises a chain of logic circuits of the bistable type which have selectable input terminals feedback connected by a storage and control element and logic gate circuits of the OR-type, and connected to a serial line through respective internal switches communicating the serial line to input terminals of the logic circuits in said chain, the serial line forming an input to a flip-flop of the D type which is the output element of the register.

Successive approximation shift register with reduced latency

A toggle flip-flop with reduced integration area, comprising a flip-flop of the D-type with an inverting input stage and a master-slave portion. Three transistors connected to the inverting stage form a logic gate of the XOR type whereto the output terminal of the master-slave portion is fed back.

Toggle flip-flop network with a reduced integration area

A digital-to-analog converter includes a potentiometric string suitable for realizing a relatively high number of bits that significantly reduces the silicon area requirement and simplifies mismatch compensation. The structure includes a first resistance string to realize a first DAC to convert a first number of most significative bits, and a second potentiometric string functionally connected in cascade to the first, but realized with MOS transistors. The structure of the invention allows the coupling of the two DACs in cascade by exploiting the MOS transistors that form the second potentiometric string, that is, the second DAC, thus avoiding the use of operational switches or amplifiers which may provide error sources. Moreover, the structure of the invention lends itself to the implementation of efficient compensation circuits for integral and differential linearity errors.

Compensated MOS string and DAC employing such a potentiometric string

Masking of switching noise is implemented in the driving system of an 'H' bridge stage by exploiting the periodic signal generated by a PWM control circuit (normally present in the control system for controlling the 'H' bridge in an open-loop mode) for masking the decay time of the disturbances caused by the switching from off-to-on of a first pair of switches of the bridge that drive a current in a certain direction through the load. This is implemented by keeping high for a preset period of time the periodic signal generated by the PWM circuit and varying the duty-cycle of the signal for regulating the mask time in function of the load characteristics. The system further comprises the masking of the decay interval of the disturbances caused by the switching from on-to-off of the first pair of switches and from off-to-on of the other pair of switches that provides a current ricirculation path of the energy stored in the reactance of the load, for a preset number of clock cycles, thus impeding any subsequent switching for the duration of this second mask. This second mask may be realized in different ways. The use of an up-counter and a programmable comparator is preferred.

Masking of switching noise in controlling a 'H' bridge

A successive approximation shift register without redundancy for a finite-state machine of the sequential type, is also effective to store the machine states. The shift register comprises a chain of logic circuits of the bistable type (FF0,FF1, . . . ) having an input stage with selectable signal inputs which are feedback connected through logic OR gate circuits (OR0,OR1, . . . ,OR6).

Successive approximation and shift register without redundancy

A sense and protection circuit against short circuits for digital outputs, comprising a logic gating circuit of the exclusive OR type (EX1) which has a first input terminal connected to a signal input node (IN) and an output terminal which is connected to an input terminal of a signal level shifter output stage (B). A second logic gating circuit of the exclusive OR type (EX2) has a first input terminal connected to the input node (IN) and a second input terminal connected, through an inverting circuit (IN1), to an output terminal (OUT) of the output stage (B). A second input terminal of the first logic gate circuit is coupled to an output terminal of the second logic gate circuit through a comparator circuit (SCH1) and a delay circuit means (C,R,D).

Circuit for detection and protection against short circuits for digital

A flip-flop of the D type capable of loading data asynchronously and comprising two latches, a master and a slave one, connected in series with each other, is characterized in that each of these comprises an interface and selection circuit for input signals transferable in either the synchronous or the asynchronous manner, and a logic gate circuit which is input such signals and, in an asynchronous manner, control signals effective to establish the latch own states.

D flip-flop having asynchronous data loading

A bistable logic network of the sequential type, responsive to the edges of input signals, comprising first and second input SR flip-flops which are connected to an output SR flip-flop through two transfer and block logic gates. Each of said logic gates has two input terminals connected to the output terminal and to one input terminal of an input flip-flop. The output terminals of the output flip-flop are feedback connected to the other input terminals of the two input flip-flops.

Bistable sequential logic network that is sensitive to the edges of

A power-on reset circuit which employs a supply voltage sensing branch for triggering a first inverter of a pair of cascaded inverters. The intrinsic static consumption of such a POR circuit is strongly reduced by employing a current generator, which is automatically forced to deliver a reduced current during the operation of the integrated circuit, for biasing two transistors functionally connected in said voltage sensing branch into a subthreshold operating condition.

Power-on reset circuit having a low static power consumption

A decoded counter employing a shift register and a zero-detect circuit has the ability of returning to a correct state within a limited number of clock cycles if an invalid state is accidentally assumed by the counter. One of the flip-flops is provided with synchronous set while all the other flip-flops of the shift register are provided with synchronous reset. The output of the last flip-flop of the register drives a single set-reset line common to all the flip-flops and the pull-up line of the zero-detect circuit is connected to the input of the first flip-flop of the register. Optionally, one of the flip-flops may be provided with asynchronous set and the others with an asynchronous reset, for initializing the counter in a certain state through a single clear-load line.

Decoded counter with error check and self-correction

In a half-bridge output stage employing a complementary pair of output power transistors, each driven through an integrating stage for controlling the slew-rate, a single integration capacitance is conveniently shared by the two integrating stages that drive the power transistors. A pair of switches connect the single integrating capacitance to the input of either one of the two integrating stages and are controlled by a pair of nonoverlapping signals that have a certain advance with respect to the pair of logic signals that drive the half-bridge stage. In the case of a driving system of a multi-phase machine, the two configuring switches of the single integration capacitor may be driven by a pair of control signals that drive a different phase winding of the multi-phase machine, thus eliminating the need for dedicated circuitry for generating said pair of anticipated signals to control the configuration switches.

Power-transistor slew-rate controller employing only a single capacitor

A programmable time-intervals generator comprising first and second digital counters, a memory, a digital divider and a digital adder. On the occurrence of a first event, the first counter starts counting, and on the occurrence of a second event, only the most significant bits of the number counted up to then are stored, thereby providing a division by truncation. From the stored number, at least two discrete fractions are obtained by the divider, whereafter said fractions are summed at the adder which operates on strings of bits. The second counter counts down the sum number and, on becoming cleared, generates a signal.

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