Sgs-thomson Microelectronics S.r.l.

Stmicroelectronics S.r.l.

Sgs-microelectronics S.r.l.

Fabrizio Martignoni

Claudio Diazzi

Mario Tarantola

Riccardo Depetro

Enrico Scian

Albino Pidutti

Mattia Fausto Moretti

Ambrogio Bogani

Fabio Vio

Alberto Gussoni

Valerio Lo Muzzo

Enrico M Ravanelli

A current monitoring circuit includes: an output terminal configured to be coupled to a controller; an inverter having an output coupled to the output terminal; a first transconductance amplifier having first and second inputs configured to be coupled across a sense resistive element, and an output coupled to an input of the inverter; and a current generator having a second transconductance amplifier configured to generate a reference current at an output of the current generator based on a reference voltage, the output of the current generator being coupled to the input of the inverter, where the output of the inverter is configured to be in a first state when a load current flowing through the sense resistive element is higher than a predetermined threshold, and in a second state when the load current is lower than the predetermined threshold, and where the predetermined threshold is based on the reference current.

High-speed AFE for current monitoring applications

The invention relates to an electronic level shifter circuit for driving a high-voltage output stage. This output stage comprises a complementary pair of transistors connected between first and second supply voltage references, and at least one PMOS pull-up transistor connected in series with an NMOS pull-down transistor. An additional transistor is connected in parallel with the pull-up transistor, and the driver circuit has a first output connected to the control terminal of the pull-up transistor and a second output connected to the control terminal of the additional transistor.

High voltage level shifter for driving an output stage

A method, and related circuit, prevent the triggering of a parasitic transistor in an output stage of an electronic circuit. The stage includes a transistor pair with at least one transistor of the pull-up PMOS type having respective source, gate and drain terminals and a body terminal, and a parasitic bipolar transistor having a terminal connected to the body terminal. The method includes the steps of providing a capacitor connected between the body and source terminals of the PMOS transistor; and using a control circuit to suppress the body effect of the pull-up PMOS transistor.

Method and an auxiliary circuit for preventing the triggering of a parasitic transistor in an output stage of an electronic circuit

The invention relates to a high-voltage final output stage for driving an electric load, of the type which comprises a complementary pair of transistors connected between first and second supply voltage references, and at least one PMOS pull-up transistor connected in series with an NMOS pull-down transistor. The stage comprises an additional PMOS transistor connected in parallel with the pull-up transistor and having the body terminal in common therewith. More particularly, the body terminals of both PMOS transistors are formed in the semiconductor within a common well which can withstand high voltages, and the additional transistor is a thick oxide PMOS power transistor.

High voltage output stage for driving an electric load

A charging circuit for a bootstrap capacitance employing an integrated LDMOS transistor and including a circuital device for preventing the turning on a parasitic transistors of the integrated LDMOS structure during transients that comprises a plurality of directly biased junctions (D1, D2, . . . , Dn) connected in series between a source and a body of the LDMOS transistor structure and at least a current generator, tied to ground potential, coupled between said body and ground, has at least one switch (INT1) between said source and a first junction (D1) of said plurality of junctions and a limiting resistance (R) connected between the body and the current generator (GEN). The switch (INT1) is kept open during a charging phase of the bootstrap capacitance (Cboot) and is closed when the charge voltage (Vboot) of the bootstrap capacitance reaches a preset threshold. Moreover, the body voltage (VB) is prevented from exceeding the source voltage (VS) plus a Vbe, by controlling a discharge path (T2) with a control stage (T1, R1) in response to a drop of the voltage on the limiting resistance (R). This body voltage control circuit is enabled by a second switch (INT2) driven in phase with the first switch (INT1).

Charging of a bootstrap capacitance through an LDMOS

The need of implementing a second local oscillator in addition to the drive oscillator, for timing the different phases of the starting process of a half-bridge or bridge stage driving an external load, such as a fluorescent lamp, is avoided by employing a timing counter to count the number of oscillations produced by the drive oscillator, and a digital-to-analog converter for controlling the frequency of oscillation of the drive oscillator.

Timing of different phases in an ignition circuit

A device for protecting an integrated circuit against electrostatic discharges, and adapted for connection between a terminal and a ground of the integrated circuit, which includes a first transistor (Q2) connected between that terminal and ground by its emitter terminal and collector terminal, respectively, and a second transistor (Q1) which has its base terminal connected to the base terminal of the first transistor. The emitter and collector terminals of the second transistor (Q2) are connected to the collector of the first transistor (Q1).

Device for the protection of an integrated circuit against electrostatic

A control circuit for a power transistor, connected between two supply terminals in series with a load. The control circuit comprises a control logic circuit which produces a signal at two levels with respect to a reference terminal, a level shifter connected between the control circuit and the power transistor, which produces a signal at two levels relative to the node between the power transistor and the load. The level shifter comprises a flip-flop the output of which controls the power transistor, and an electronic switch, for example a MOSFET transistor, connected between the 'set' input of the flip-flop and the node and controlled by the 'reset' input of the flip-flop in such a way as to be closed when the 'reset' input is greater, by a predetermined value, than that of the node. The electronic switch prevents the parasitic current flowing through the set and reset inputs from erroneously switching the power transistor.

Control circuit with a level shifter for switching an electronic switch

A circuit for controlling a power transistor connected in series with a load. The circuit comprises a control logic circuit which produces a signal at two levels with respect to a reference terminal, a level shifter connected between the control circuit and the power transistor, and which produces a signal at two levels referred to the node between the power transistor and the load. The level shifter includes a flip-flop the output of which controls the power transistor as well as two transistors driven by the control logic circuit to switch alternately and provide switching signals on the 'set' and 'reset' inputs of the flip-flop via two resistors. Two parasitic current generators inject current into the two resistors during the phase in which the power transistor is cut off. To prevent this current from causing unwanted switching of the flip-flop, a resistor connected to the 'set' terminal of the flip-flop has a lower resistance than that of the other resistor.

Integrated control circuit with a level shifter for switching an

A level shifter, particularly suited for driving power stages for supplying power to integrated circuits, includes a DMOS transistor (40) which is driven by a digital signal source (42) and has a load resistor (44) as its drain load. A shifted output signal develops at the ends of said load resistor. The drain (V1) of the DMOS transistor is connected to the input of an inverter (46), while a Zener diode (54) and a second transistor (52) are connected in parallel with the load resistor (44), the gate of the second transistor (52) being driven by the output of the inverter (46). The output of the inverter (46) can be connected to the input of a drive stage (48), the output of which drives a power stage (50) for supplying power to an integrated circuit.

Single-drive level shifter with low dynamic impedance

A driving circuit for driving a floating circuit (28) responsive to a digital signal (IN) includes two DMOS transistors (10, 12) which are driven in opposite phase on their respective gates starting from the digital signal. The two DMOS transistors are biased by a current source which is formed by a current mirror (16, 18), which mirrors a reference current (I.sub.BIAS), and by an auxiliary circuit (34-44) for injecting an additional current pulse during switching. Two MOS transistors (20, 22) serve as the respective loads for the two DMOS transistors. The MOS transistors can be P-channel transistors, in which event the gate of each MOS transistor (20, 22) can be connected to the drain of the other MOS transistor. Two Zener diodes (24, 26) can be employed to limit the voltage between the gate and source of the respective MOS transistor. The driving output of the floating circuit (28) can be the drain of one of the DMOS transistors.

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Morazzone, Italy

Fabrizio Martignoni