Sgs-thomson Microelectronics S.r.l.

Stefania Boiocchi

Marco Masini

Edoardo Botti

Sandro Storti

Claudio Tavazzani

A power supply regulator comprising a regulated-voltage source; a buffer connected to the voltage source; and a diode connected to the output of the buffer. A bootstrap capacitor is located between the diode and the output of a power stage; and the output of the power stage is switched between a low and a high value by a digital signal also supplied to the input of the buffer which therefore generates a switched regulated output voltage varying between a first value equal to the regulated voltage and a second lower value. The switched regulated voltage switches from the first to the second value before the output of the power stage switches to high, thus immediately disabling the diode and preventing current spikes due to minority carriers in the diode from being transmitted to the regulated-voltage source. The switched regulated voltage switches from the second to the first value before the output of the power stage switches to low, to permit charging of the bootstrap capacitor to the regulated voltage when the output is low.

Bootstrap line power supply regulator with no filter capacitor

An amplifier is formed by an astable multivibrator having a signal output supplying a two-state output signal to a power stage, that presents an output voltage (V.sub.o) switching between a first and second value. The output voltage presents a duty cycle varying with the input signal (V.sub.in) of the multivibrator. The amplifier, when connected between first and second supply lines that are symmetrical with respect to ground and are subject to supply noise, comprises a current source for generating the bias current of the astable multivibrator and supplying a current (I) that is switchable at each half cycle. The value of the current at each half cycle is proportional to the absolute value of the output voltage (V.sub.o) of the amplifier to vary the duty cycle of the amplifier in a manner correlated the supply noise, so that the average output voltage value is zero.

Single-output dual-supply class D amplifier

A single-pole negative feedback D-class amplifier having first and second input terminals for coupling to a signal source and an output terminal through which it transfers pulse modulated signals to a demodulating filter. A first resistor is feedback connected between the output terminal and an input circuit node connected to the second input terminal. A second resistor is connected between the input circuit node and the second input terminal. A capacitor is connected between the input circuit node and the first input terminal.

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Certosa, Italy

Stefania Boiocchi