Stmicroelectronics S.r.l.

Sgs-thomson Microelectronics S.r.l.

Sgs-microelectronics S.r.l.

Mario Tarantola

Claudio Diazzi

Fabrizio Martignoni

Roberto Gariboldi

Giuseppe Cantone

Angelo Genova

Roberto Giorgio Bardelli

A successive-approximation analog-digital converter including a logic control circuit timed by means of an external clock signal clock. The logic control circuit includes a register containing a first digital signal formed of N bits, which is the product of a first analog-digital conversion. The logic control circuit is suitable for producing a second digital signal formed of N bits through a second analog-digital conversion in N clock cycles. This analog-digital converter converts the second digital signal sent by the logic circuit to a second analog signal. A comparator compares the first analog signal with the second analog signal which has been input to the analog-digital converter. The converter includes a device which enables the increase of the first analog signal in output from the digital-analog converter and in input to the comparator by a preset value (Voffs) when the bit of the first digital signal which corresponds in position to the bit of the second digital signal which must be decided in a clock cycle is zero.

Successive-approximation analog-digital converter and related operating method

A circuit for charging a capacitance using an LDMOS integrated transistor functioning as a source follower and controlled, in a manner to emulate a high voltage charging diode of the capacitance. The LDMOS transistor is controlled via a bootstrap capacitor charged by a diode at the supply voltage of the circuit, and by an inverter driven by a logic control circuit as a function of a Low Gate Drive Signal and of a second logic signal which is active during a phase wherein the supply voltage is lower than the minimum switch-on voltage of the integrated circuit. The circuit uses a first zener diode to charge the bootstrap capacitor and the source of the transistor is connected to the supply node through a second zener diode.

Turn-off circuit for an LDMOS in presence of a reverse current

A circuit for charging a capacitance using an LDMOS integrated transistor functioning as a source follower stage and controlled, in a manner to emulate a high voltage charging diode of the capacitance via a bootstrap capacitor charged by a diode connected to the supply node of the circuit, and by an inverter driven by a logic control circuit as a function of a first Low Gate Drive Signal and of a second logic signal. The second logic signal is active during a phase where the supply voltage is lower than the minimum switch-on voltage of the integrated circuit. The circuit further includes a second inverter functionally referred to the charging node of the bootstrap capacitor and to the voltage of the output node of the inverter. The second inverter has an input coupled to the second logic signal and an output coupled to the gate node of the LDMOS transistor for preventing accidental undue switch-on of the LDMOS transistor.

Protection circuit for controlling the gate voltage of a hv LDMOS

A circuit for charging a capacitance using an LDMOS integrated transistor controlled in a manner to emulate a high voltage charging diode of the capacitance. The circuit avoids the switch-on of parasitic bipolar transistors of the LDMOS structure during transient states. The circuit includes a number of junctions directly biased between a source node and a body node of the LDMOS transistor, a current generator referred to a ground of the circuit, at least one switch between the source and a first junction of a chain of directly biased junctions, and a limiting resistor connected between the body and the current generator referred to ground. The switch is open during a charging phase of the capacitance and is closed when the charging voltage of the capacitance exceeds a preestablished threshold responsive to a control signal. The switch is controlled by a logic signal active during the phase in which the supply voltage of the integrated circuit is lower than the minimum switch-on voltage of the same integrated circuit, for charging the body with a current whose maximum value is limited to a preestablished value.

Control of the body voltage of a HV LDMOS

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 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.

Growing community of inventors

Bareggio, Italy

Mario Tarantola