Sgs-thomson Microelectronics S.r.l.

Antonella Baiocchi

Angelo Alzati

Aldo Vittorio Novelli

Pietro Menniti

Sandro Cerato

A spike filtering circuit for a logic signal comprises a signal transfer circuit formed by a first transfer gate followed by a pair of inverters, functionally connected in series between the input terminal and the output terminal of the circuit and a second transfer gate connected between the output terminal and the input node of the first of said two inverters. The two transfer gates are driven in phase opposition to each other by means of a pair of control signals in phase opposition to each other which are generated by a control circuit functioning in a feedback mode. Basically the control circuit is formed by an exclusive-OR gate having two inputs connected to the output terminal of the circuit directly and through a delay network, respectively. Through an output node of the exclusive-OR gate is produced a first control signal from which the pair of control signals in phase opposition to each other are derived by means of inverting stages. The delay network introduces a delay after a transition of the signal on the output terminal of the circuit has occurred during which said first transfer gate is momentarily disabled and said second transfer gate is enabled in order to maintain on the output terminal the state reached with the first transition for a period of time sufficiently long to allow the decay of spikes which may be been generated by said transition of the logic signal. By employing a NAND gate and an inverter connected in cascade to the output of said exclusive-OR gate, the filtering circuit may be initialled by applying an enabling signal to a second input of said NAND gate.

Spike filtering circuit for logic signals

An electronic circuit for measuring and controlling an electric current flowing through an inductive electric load, being of a type which comprises a first, field-effect power transistor connected to the load and a second, sensing transistor having its source electrode connected to the source electrode of the first transistor, further comprises a voltage comparator having respective inputs connected to the corresponding drain electrodes of said transistors, and an electronic switch connected in ahead of the gate electrode of the power transistor and linked to the comparator output.

Inductive load current controller

A circuit device, made up of a reduced number of components, for simultaneously turning on a plurality of power transistors, being of a type adapted to be connected between the output of an oscillator and the bootstrap input of a turn-on circuit which are both incorporated into an integrated circuit also incorporating said transistors, further comprises:

Circuit device, made up of a reduced number of components, for

A low-absorption circuit device for controlling into the on state a power transistor, in particular a D MOS transistor having conventional gate, drain, and source electrodes, and adapted to drive electrical loads by changing over from an off state to an on state in which there appears on the gate electrode a predetermined voltage value, comprises a first turn-on circuit connected to one pole of a voltage supply, a second turn-on circuit connected to another supply voltage pole, and a comparator having respective inputs connected to the gate electrode of the power transistor and to a reference voltage pole as well as respective outputs connected to each respective turn-on circuit to activate said circuits alternately based on a comparison of the gate voltage of the power transistor with the predetermined reference voltage.

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Vigevano, Italy

Antonella Baiocchi