TECHNICAL FIELD

The present disclosure relates generally to a voltage regulator, more particularly, to a dual loop voltage regulator.

BACKGROUND

Voltage regulators control or adjust a voltage received from a source to meet specific requirements of an electronic device. Voltage regulators may increase or decrease the voltage provided by the source and provide a substantially constant voltage to the electronic device despite variations in current dissipated by the electronic device or fluctuations of the voltage received from the source.

Voltage regulators are used in a variety of electronic devices and systems to provide a constant regulated voltage. Conventionally, voltage regulators may include a high-gain amplifier to reduce a direct current (DC) regulation error. For example, a high-gain amplifier may have a high gain by increasing an output resistance of the amplifier through a combination of techniques such as multiple stages, long transistor channel lengths, cascoding, etc. However, the increased output resistance may decrease a phase margin of the amplifier.

A conventional voltage regulator design may sacrifice a phase margin to achieve a high gain and reduce a DC regulation error or conversely sacrifice DC regulation to achieve a desired phase margin.

SUMMARY

According to one embodiment, a voltage regulator includes a first amplifier having a first gain and a first frequency bandwidth, and generating a first voltage output; a second amplifier having a second gain that is lower than the first gain and a second frequency bandwidth that is higher than the first frequency bandwidth, and generating a second voltage output; a summer generating a summed voltage output based on the first voltage output and the second voltage output; and a transistor connected to the summer and generating a regulated voltage based on the summed voltage output of the summer.

According to another embodiment, a voltage regulator includes a first amplifier comprising an impedance translating transistor and generating a first voltage output; a second amplifier generating a second voltage output; and a pass transistor connected to the first amplifier and generating a regulated voltage based on a voltage output of the first amplifier. The first amplifier has a first gain and a first frequency bandwidth, and the second amplifier has a second gain that is lower than the first gain and a second frequency bandwidth that is higher than the first frequency bandwidth.

The above and other preferred features, including various novel details of implementation and combination of events, will now be more particularly described with reference to the accompanying figures and pointed out in the claims. It will be understood that the particular systems and methods described herein are shown by way of illustration only and not as limitations. As will be understood by those skilled in the art, the principles and features described herein may be employed in various and numerous embodiments without departing from the scope of the present disclosure.

