Abstract: An integrated circuit chip includes trenches at least partially surrounding a critical portion of a circuit that is sensitive to temperature variations. The trenches are locally interrupted in order to permit circuit connections to pass between the critical portion and an outer portion containing a remainder of the circuit. The critical portion includes heating resistors and a temperature sensor.

Abstract: An amplifier includes a pair of transistors connected in a differential stage, and a bias current source connected to a common node of the differential stage. A slew-rate compensation circuit is configured to derive from the common node a dynamic compensation current during a phase in which the voltage of the common node varies.

Abstract: An integrated circuit chip includes trenches at least partially surrounding a critical portion of a circuit that is sensitive to temperature variations. The trenches are locally interrupted in order to permit circuit connections to pass between the critical portion and an outer portion containing a remainder of the circuit. The critical portion includes heating resistors and a temperature sensor.

Abstract: An amplifier includes a pair of transistors connected in a differential stage, and a bias current source connected to a common node of the differential stage. A slew-rate compensation circuit is configured to derive from the common node a dynamic compensation current during a phase in which the voltage of the common node varies.

Abstract: A low drop-out DC voltage regulator regulates a voltage from a DC supply and includes: a pass device controllable to maintain a voltage at an output of the regulator and arranged to provide a first current from the DC supply, at least part of said first current being provided to a load coupled to the output of the regulator; and a current regulator coupled to said pass device and to the output of the regulator. The current regulator is arranged to conduct a second current controllable such that the first current through said pass device remains constant irrespective of variations in a load current to said load.

Abstract: A method for regulating the biasing voltage of column control circuits of an array screen formed of LEDs distributed in lines and columns, the column control circuits being adapted to turning on at least one LED of a line. The method includes increasing the biasing voltage when the current flowing through at least one activated LED is smaller than a determined luminance current and of decreasing the biasing voltage when the current flowing through each activated LED is equal to the determined luminance current.

Abstract: A low drop-out DC voltage regulator regulates a voltage from a DC supply and includes: a pass device controllable to maintain a voltage at an output of the regulator and arranged to provide a first current from the DC supply, at least part of said first current being provided to a load coupled to the output of the regulator; and a current regulator coupled to said pass device and to the output of the regulator. The current regulator is arranged to conduct a second current controllable such that the first current through said pass device remains constant irrespective of variations in a load current to said load.

Abstract: An intermediate stage of a high-voltage inverting amplifier includes a drive transistor (MB5) of the thin-gate-oxide high-voltage MOS type connected between a supply terminal and the gate of an output transistor (M28). At least one first diode (DB) is included in the intermediate stage, wherein the cathode of that diode is connected to the gate of the drive transistor and the anode is connected to a level transposition stage of the amplifier. A control circuit is connected to the gate of the drive transistor so as to enable it to conduct when an initially zero supply voltage reaches the threshold voltage of the drive transistor. This causes the output transistor to conduct more quickly with increased supply voltage than would be experienced with prior art designs.

Abstract: A method for regulating the biasing voltage of column control circuits of an array screen formed of LEDs distributed in lines and columns, the column control circuits being adapted to turning on at least one LED of a line. The method consists of increasing the biasing voltage when the current flowing through at least one activated LED is smaller than a determined luminance current and of decreasing the biasing voltage when the current flowing through each activated LED is equal to the determined luminance current.

Abstract: A circuit for generating a pulse-width-modulated signal comprises a phase-locked loop (PLL) having a duty-cycle-insensitive phase comparator and a Sigma-Delta pulse width modulation circuit suitable for providing the voltage-controlled oscillator function of the PLL. Thereby, frequency of the signal generated is synchronized by the PLL to the specified frequency of a synchronization signal, and is thus independent of the duty cycle.

Abstract: An intermediate stage of a high-voltage inverting amplifier includes a drive transistor (MB5) of the thin-gate-oxide high-voltage MOS type connected between a supply terminal and the gate of an output transistor (M28). At least one first diode (DB) is included in the intermediate stage, wherein the cathode of that diode is connected to the gate of the drive transistor and the anode is connected to a level transposition stage of the amplifier. A control circuit is connected to the gate of the drive transistor so as to enable it to conduct when an initially zero supply voltage reaches the threshold voltage of the drive transistor. This causes the output transistor to conduct more quickly with increased supply voltage than would be experienced with prior art designs.

Abstract: Disclosed is a device to control a circuit for the vertical deflection of a spot scanning a screen, and more particularly a control device whose output amplifier stage works in class D mode at the rate of a switching signal called a first switching signal. The control device has an internal auxiliary supply to generate the overvoltage needed for the fast flyback of the spot. This auxiliary power supply is a switching voltage generation circuit whose switching signal, called a second switching signal, is synchronous with the first switching signal. The present invention has been shown to used advantageously in television screens and/or computer screens.

Abstract: A circuit for generating a pulse-width-modulated signal comprises a phase-locked loop (PLL) having a duty-cycle-insensitive phase comparator and a Sigma-Delta pulse width modulation circuit suitable for providing the voltage-controlled oscillator function of the PLL. Thereby, frequency of the signal generated is synchronized by the PLL to the specified frequency of a synchronization signal, and is thus independent of the duty cycle.

Abstract: Disclosed is a device to control a circuit for the vertical deflection of a spot scanning a screen, and more particularly a control device whose output amplifier stage works in class D mode at the rate of a switching signal called a first switching signal. The control device has an internal auxiliary supply to generate the overvoltage needed for the fast flyback of the spot. This auxiliary power supply is a switching voltage generation circuit whose switching signal, called a second switching signal, is synchronous with the first switching signal. The present invention has been shown to used advantageously in television screens and/or computer screens.

Abstract: The control device includes an output amplifier stage ETS supplied by a main supply for controlling the vertical scan of the spot, and an auxiliary supply capable of delivering an overvoltage and a first two-way switch connected to the output stage and controllable to allow the overvoltage to be delivered to the vertical deflection circuit for flyback of the spot. The output stage is a stage having at least two transistors which are capable of operating in alternating switching mode, at least for control of the vertical scan of the spot, this stage being associated with a smoothing filter connected to the common terminal of the two transistors. The device includes a second two-way switch connected between a first transistor of the output stage and a first terminal of the main supply and controllable to prevent delivery of the overvoltage during control of the vertical scan of the spot.

Abstract: A device for limiting the output current of an operational amplifier of the type including an output stage having an output transistor, including circuitry for limiting the biasing current of a differential input stage of the operational amplifier to a value determined by a measurement resistor connected between the output transistor and an output terminal of the operational amplifier.

Abstract: A device for correcting the linearity of ramps of a saw-tooth signal provided across a capacitor, charged by a first current source and periodically discharged at a desired frequency. The device modulates the charging current of the capacitor by a correction current to render the ramps of the signal not linear. In addition, the device includes circuitry to render the correction current proportional to the current provided by the first current source.

Abstract: In a switching power supply controlled by modulated width pulses obtained by comparison between a saw-tooth voltage (15) oscillating between first and second levels and a servo control voltage (19), the servo control voltage is initially set to a value external to the oscillation interval of the saw-tooth, then, in a first phase, varies up to a first level (dead time) and, in a second phase, varies from the first to the second level for supplying control pulses having progressively increasing widths. A circuit (45, 50) ensures the variation of the servo control voltage during the first phase according to a first slope and then the variation of said servo control voltage during the second phase according to a second slope, lower than the first one, and a circuit (60) causes the slope switching after the detection of the first control pulse.

Abstract: An external-power stage suitable for use with television sets, for example. A transformer is provided with control circuits in both the primary side and the secondary side. Each of the control circuits have pulse-width modulators which provide pulses to an electronic switch. The control circuit on the primary side provides pulses to that switch of varying pulse width and of sufficient magnitude to maintain the television set in a standby mode. The control circuit in the secondary side of the transformer, on the other hand, comes into operation when the television set is turned on and provides pulses to the electronic switch while operating with the control circuit in the primary side for a predetermined period of time. Thereafter, the control circuit in the secondary side takes over the function of providing pulses to the electronic switch while the control circuit on the primary side is switched to an inoperative stage.

Abstract: A protection device for switch mode power supplies includes a main switch controlled by the output signals of a flip-flop. The flip-flop input receives regulation control signals. A first protection circuit supplies priority signals with respect to the regulation signals on the reset input of the flip-flop. The protection device also includes a cycle detector of the first protection circuit, a memory for accumulating at each cycle a value proportional to the duration between a signal of the detector and the set signal associated with the regulation cycle of the following cycle, and inhibiting of the flip-flop when the memory has accumulated a signal higher than a predetermined threshold.