Abstract: The present invention relates to a digital control circuit of the P.I. (Proportional Integral) type, receiving an error signal (Error) at an input terminal (IN1) and adapted to provide, at an output terminal (OUT1), a PWM [Pulse Width Modulated] output signal (PWM Output). The circuit is of a type which comprises at least one analog-to-digital converter (100, 100*) connected to the input terminal (IN) and to the output terminal (OUTI) through at least one integrative/proportional branch (120, 121, 130, 134).

Abstract: A system for diagnosing a driver and detecting circuit anomalies therein includes: voltage comparator circuits for generating diagnostic logic signals, each of which indicates the existence of a corresponding type of anomaly; and a coding circuit to receive the diagnostic logic signals and to output information relating to an overall operating state of the driver. The coding circuit includes a first portion to provide at its output first logic input signals indicating the last anomaly to occur since a system reset operation. The coding circuit also includes a second portion for coding the first logic input signals. The second portion includes a sequential logic network to receive the first logic input signals and at least one second logic signal indicating the current operating phase of the driver. The second portion provides, as a function of the first and second logic signals, a stable internal state to determine the output information in the form of an N bit coded word.

Abstract: A circuit extends the output voltage range of an integrator circuit wherein the input signal is used to produce an output signal, and the voltage of the output signal develops monotonically within a predetermined range of possible values. The integrator circuit is driven within an integration time period such that each time the signal at its output reaches a limit of the range of values, the integrator circuit starts a subsequent integration stage of the input signal in which the output signal develops again within the above-mentioned range. This takes place by resetting the integrator circuit or by a reversal of the characteristic slope of the output signal. This is combined with storing the number of occasions on which these interventions have occurred as determined by a scounter.

Abstract: A protection circuit of a diagnostic output line (K-line) of a control unit for protection of the control unit in the event of a ground disconnection or of a “below ground” condition is provided. The diagnostic output line includes a first interface DMOS transistor with a source connected to ground and a drain coupled to the diagnostic output line through a second DMOS transistor with a source connected to the output line and a drain connected to the source of the first DMOS transistor. The protection circuit also includes a comparator for the voltage of the diagnostic output line with the potential of the ground node, and a two-input logic gate, whose output controls a current generator forcing a current, limited by a resistor, on the diagnostic output line.

Abstract: A circuit extends the output voltage range of an integrator circuit wherein the input signal is used to produce an output signal, and the voltage of the output signal develops monotonically within a predetermined range of possible values. The integrator circuit is driven within an integration time period such that each time the signal at its output reaches a limit of the range of values, the integrator circuit starts a subsequent integration stage of the input signal in which the output signal develops again within the above-mentioned range. This takes place by resetting the integrator circuit or by a reversal of the characteristic slope of the output signal. This is combined with storing the number of occasions on which these interventions have occurred as determined by a counter.

Abstract: An amplitude and phase demodulator circuit for signals with very low modulation index, including: amplifier circuitry adapted to amplify a modulated signal coming from a transmitter, the modulated signal being composed by a carrier and by a modulating component, circuitry adapted to cancel said carrier from said modulated signal; the circuitry adapted to cancel the carrier receiving in input the output signal of the amplifier circuitry and a sync signal coming from the transmitter, the output signal of the amplifier circuitry being delivered to receiver circuitry.

Abstract: A differential amplifier provides a high common mode rejection while maintaining substantially unchanged the input dynamic range. The differential amplifier includes a comparator having inputs to which are applied the two input signals, which are also applied to an operational amplifier, so that the comparator outputs a signal whose sign is indicative of the sign of the difference between the two input signals. The output of the operational amplifier is feedback to one of the inputs of the operational amplifier through a current mirror. This feedback signal is switched between the non-inverting input of the operational amplifier and the inverting input of the operational amplifier. The switching of the feedback signal ensures negative feedback, and is dependent upon the sign of the difference detected by the comparator.

Abstract: An electronic circuit with suppression of high-voltage transients on the power supply line includes first and second power transistors series-connected between first and second power supplies, and first and second driving circuits for respective first and second power transistors. The first driving circuit includes a first diode and a first Zener diode, and the second driving circuit includes a second diode and a second Zener diode. Anodes of the first diode and the first Zener diode are connected to the cathode of the second Zener diode. A cathode of the first Zener diode is connected to the first power supply. A cathode of the first diode is connected to a gate of the first power transistor. Anodes of the second diode and the second Zener diode are connected together. A cathode of the second diode is connected to a gate of the second power transistor.

Abstract: A voltage-regulator circuit with a low voltage drop uses a DMOS power transistor driven by a charge pump. The control circuit includes two feedback loops: a first feedback loop having a high gain and accuracy but low response speed, and a second feedback loop having a wide passband and fast response speed, but low gain.

Abstract: Saturation of a bipolar power transistor is controlled by sensing the current which is eventually injected into the substrate of the integrated circuit by the saturating transistor and using this signal for exerting a limiting action on the current which is driven to the base of the power transistor by a dedicated driving circuit. Unlike the prior art antisaturation systems, it is no longer necessary to precisely monitor the operating voltages across the terminals of the bipolar power transistor. A suitable sensing resistance may be integrated conveniently at a distance from the often complex integrated structure of the bipolar transistor. The system of the invention offers numerous advantages and ensures intervention of the antisaturation circuit only when the power transistor has positively reached a state of saturation, but well before any unwanted consequence.

Abstract: The electronic interface circuit can perform ratiometric processing and driving of a signal generated by a fuel-level detector of a vehicle. The circuit uses a current mirror configured so as to send one half of the output current to the input resistance and one half of the output current to earth. The current mirror is controlled by a voltage taken from the input resistance and by a voltage taken from a resistive divider, the latter voltage having been filtered by a low-pass filter, so as to achieve ratiometric processing of the input signal.

Abstract: A circuit for controlling the reserve lamp of a vehicle's fuel level indicator instrument. The circuit uses a switch controlled by an extremely asymmetric clock signal periodically to switch, for a very short time, the signal provided by the level sensor coupled to a comparator operable to compare this signal with a threshold value for the purpose of determining the state of the reserve lamp.

Abstract: A troubleshooting circuit for locating malfunctions while driving an electric load by means of a bridge stage (M1, M2, M3, M4) which is connected between ground (GND) and the power supply (+VCC) in series with first and second resistors (Rsl, Rsh), respectively. First (COMP1) and second (COMP2) threshold comparators are coupled to the first resistor to sense a short-circuit to battery (+VCC) and an open-load condition, respectively. Coupled to the second resistor is a third threshold comparator (COMP3) adapted to sense a short-circuit to ground. The output signals from the comparators are sampled through flip-flops (FF1, FF2, FF3, FF4, FF5, FF6) upon a transistor in the bridge being switched to the off state.

Abstract: A circuit for diagnosing the state of a load connected to a driver includes a DMOS transistor interposed between a terminal of the load and voltage comparator circuits. The DMOS transistor limits the maximum voltage input to the comparators to thereby reduce the circuit area occupied by the comparators and consequently to reduce the cost of the diagnosis circuit.

Abstract: The circuit includes two regulating loops connected in parallel to each other. A slow regulating loop presents a lower first intervention threshold, and a fast regulating loop has a higher second intervention threshold. The slow regulating loop is low-gain and frequency-stable for accurately controlling the maximum value of the current supplied by the driver in the event of slow overloads or transient states. In the event of rapid overloads, the current supply increases rapidly and the fast regulating loop is turned on to rapidly discharge the parasitic capacitance of the driver.

Abstract: The present invention relates to a circuit for processing the output signal from a resistive analog sensor, comprising firstly a digital filter, and secondly a module forming a digital-to-impedance converter, which filter and module are interposed in series between the output of the sensor and the input of an associated load, the digital-to-impedance converter presenting an output impedance that is variable as a function of the output signal from the digital filter, which is equivalent to the output resistance of the sensor.

Abstract: An improved circuit for controlling the maximum current in a MOS power transistor, in which resistor is in series with the drain-source path of the MOS power transistor. The supply terminal of a transconductance operational amplifier is connected to the output of a voltage-raising or charge pump circuit which can output a voltage higher than that of the voltage supply to which the drain of the MOS transistor is connected. The inputs of the amplifier are connected to the resistor and its output is connected to the gate of the MOS transistor so that, in operation, the maximum current flowing through the power transistor is limited to a value proportional to a reference voltage.

Abstract: A low-drop voltage regulator includes a P-type power transistor having an input terminal connected to a supply source, an output terminal connected to a load, and a control terminal driven by the output of an operational amplifier having its non-inverting input connected to a reference voltage source and its inverting input connected to the output terminal of the power transistor. To improve the regulation characteristics of the regulator without jeopardizing stability, even under normally critical conditions, provision is made for a feedback network including a capacitive component between the output and inverting input of the operational amplifier.

Abstract: The amplitude of the hysteresis of the circuit is determined principally by the intensity of the current produced by a generator by means of a "band gap" reference voltage, an internal resistance of the circuit, and the resistances connected to the emitters of the input-stage transistors, enabling a high degree of precision to be achieved. The inputs of the circuit are defined by the bases of the input-stage transistors and therefore have high impedance. The preferred application is for forming interface circuits for sensors to be fitted in motor vehicles.

Abstract: An H-bridge circuit which includes four power transistors (an npn pull-down and a pnp pull-up for each of the output terminals). Two control circuits are connected to drive these transistors in a complementary crossover configuration, so that each control circuit can turn on the pull-up transistor on one side of the load and the pull-down transistor on the opposite side of the load. Each of the power transistors is paralleled (base-to-base) by a smaller transistor which provides a scaled current output (proportional to that of the corresponding power transistor) to the opposite control circuit. The control circuit includes static current-thresholding disable logic, which prevents turn-on until the currents through the opposite power devices have declined to threshold levels. Thus, as long as either control circuit is driving one of the pull-up transistors into in the on-state, the other control circuit will not be able to turn on the pull-down transistor which is in series with the active pull-up transistor.