Stmicroelectronics S.r.l.

Danilo Ranieri

Edoardo Botti

Davide Luigi Brambilla

Giovanni Capodivacca

Luca Celant

A method of assessing the offset on the output nodes of an amplifying channel includes generating a logic signal for signaling the existence of an offset having a level exceeding a window of permitted levels symmetric about the zero level. The window is defined by a negative limit value and by a positive limit value. The method includes establishing an interval or phase of detection by applying to an input of a detection circuit a timing pulse with a certain frequency, sensing the rising edge of the timing pulse and setting a bistable circuit, and comparing the signal on the output nodes of the amplifiers channel with the window of permitted values. The bistable circuit is reset upon the occurrence, after the initial setting, of an output signal amplitude within the window of permitted values. Failure of the bistable circuit to reset before the end of the detection phase signals an excessive offset.

Method of anomalous offset detection and a corresponding circuit

A method of voltage driving a load using a controlled current includes providing a negative feedback of an output current, measuring the output current on a collector of an output transistor of an output stage, comparing the measured output current with an input current to define a current difference, and providing the current difference at a base of the output transistor to provide the voltage driving.

Controlled current, voltage mode driving stage

A switching output power stage, including a power switching device for the supply line and a complementary power switching device for the ground rail driven in phase opposition by a pulse width modulated (PWM) drive signal, is provided with sensors detecting a substantial turn-off state of each of the two power switching devices and generating a pair of logic signals. A combinatory logic circuit combines the drive signal and the pair of logic signals and generates a pair of driving signals of opposite phase for the respective power switching devices. The switching to a turn-on state of any of the two power devices is enabled upon verifying a substantially attained turn-off state by the device complementary to the device commanded to turn-on, irrespective of the process spread and of changes of temperature load conditions and of configuration of a plurality of output stages of a multichannel amplifier.

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Sesto San Giovanni, Italy

Danilo Ranieri