Ams Ag

Alessandro Carbonini

Carlo Fiocchi

Paolo Draghi

A low-dropout regulator () comprises a differential amplifier () with a reference input () for applying a reference voltage (VIN), a feedback input () and an amplifier output (). An output transistor () has a control connection () connected to the amplifier output (), and a control section connected between a first supply potential terminal (VDD) and a voltage output () of the low-dropout regulator (). A feedback branch () with an RC-parallel connection () is coupled between the voltage output () and the feedback input (). A precharge circuit () includes a first field effect transistor () with a gate () coupled to the feedback input () and is configured to precharge the RC-parallel connection () to a threshold voltage (VTH) of the first field effect transistor ().

Low-dropout regulator and method for voltage regulation

In one embodiment a low-dropout regulator comprises a first differential amplifier (Nmos) to receive an input voltage (Vin), a power transistor (T) coupled to the first differential input pair (Nmos), the power transistor having an output (OUT) forming an output terminal of the low-dropout regulator to provide an output voltage (Vout) as a function of the input voltage (Vin), a second differential amplifier (Pmos) coupled to the first differential amplifier (Nmos), and a switching element (Mncut, Mncut) coupled between first and second differential amplifier (Nmos, Pmos), said switching element (Mncut, Mncut) being operated as a function of a feedback signal (Sfb) derived from the output voltage (Vout). The second differential amplifier (Pmos) is complementary to the first differential amplifier (Nmos). The low-dropout regulator is operated in one of two modes such that in a first mode the second differential amplifier (Pmos) is enabled and in the second mode the first differential amplifier (Nmos) is enabled and the second differential amplifier (Pmos) is disabled by means of the switching element (Mncut, Mncut).

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Redavalle, Italy

Alessandro Carbonini