Ams International Ag

Ams-Osram Ag

Cheng Zhang

Emir Serdarevic

A low-dropout regulator for low voltage applications includes a buffer circuit being arranged between an output terminal of an error amplifier and a control node of a pass device. The buffer circuit includes a driver having a first transistor being embodied as an NMOS transistor. The output terminal of the error amplifier is coupled to the control node of the first transistor. The control node of the pass device is coupled to an internal node of a first current path including the first transistor. The low-dropout regulator has high load capability, even if an input supply voltage is very low.

Low-dropout regulator for low voltage applications

An oscillator circuit includes a current controller, a first capacitor and a second capacitor. A current generator is coupled to the current controller, the first and the second capacitor, and is operable, under control of a control signal of the current controller, provide charging currents. A comparator stage comprises a first input coupled to the first capacitor, a second input coupled to the second capacitor and a reference input to be supplied with the reference voltage. The comparator stage further includes an oscillator output to provide a clock signal based on a comparison of the capacitor voltages and the reference voltage, respectively. A modulation circuit comprises an oscillator input to input the clock signal, a reference output is connected to the current generator, and is operable to alternate between the charging currents, such that a charging current is provided as reference current at the reference output and at least one charging current is provided to alternately charge/discharge the first capacitor and the second capacitor to respective capacitor voltages.

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GRAZ, Austria

Cheng Zhang