US 10,771,073 B2Granted

Frequency synthesizer with dynamically selected level shifting of the oscillating output signal

AssigneeSTMicroelectronics International N.V.

InventorNitin Gupta

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Abstract

An oscillator circuit powered by a source voltage generates an oscillating output signal. The oscillating output signal is level shifted and applied to a first input of a multiplexer. A second input of the multiplexer receives the oscillating output signal. The multiplexer selects one of the oscillating output signal and the level shifted oscillating output signal for output as a selected oscillating output signal in response to a select signal. A locked loop circuit generates controls a frequency of the oscillating output signal as a function of the selected oscillating output signal and a reference oscillating signal. The select signal further selects one of a reference voltage and the source voltage of the oscillator circuit as an error amplifier reference voltage for a voltage regulator circuit that generates the first power supply voltage.

Claims43

Dependent claims

A circuit, comprising:

an oscillator circuit powered at a source voltage and configured to generate an oscillating output signal with an amplitude at a level of the source voltage;
a first level shifter circuit powered by a first power supply voltage and configured to level shift the oscillating output signal to generate a level shifted oscillating output signal;
a first multiplexer circuit having a first input configured to receive the oscillating output signal and a second input configured to receive the level shifted oscillating output signal, wherein the first multiplexer circuit selects one of the oscillating output signal and the level shifted oscillating output signal for output as a selected oscillating output signal;
a locked loop circuit configured to control a frequency of the oscillating output signal as a function of the selected oscillating output signal and a reference oscillating signal;
and
a first voltage regulator circuit configured to generate the first power supply voltage using the source voltage as an error amplifier reference voltage.

3 more elements

A circuit, comprising:

an oscillator circuit powered at a source voltage and configured to generate an oscillating output signal with an amplitude at a level of the source voltage;
a divider circuit powered by a first power supply voltage and configured to divide the oscillating output signal to generate a feedback oscillating signal;
a phase-frequency comparator powered by a second power supply voltage and configured to compare the feedback oscillating signal to the reference oscillating signal and generate an error signal;
a current source circuit configured to generate a current in response to the error signal, wherein the source voltage of the oscillator circuit is generated in response to said current and wherein a frequency of the oscillating output signal is controlled by said current;
a first voltage regulator circuit configured to generate the first power supply voltage using the source voltage of the oscillator circuit as a first error amplifier reference voltage;
and
a second voltage regulator circuit configured to generate the second power supply voltage using a reference voltage as a second error amplifier reference voltage.

4 more elements

A circuit, comprising:

an oscillator circuit powered at a source voltage and configured to generate an oscillating output signal with an amplitude at a level of the source voltage;
a divider circuit powered by a first power supply voltage and configured to divide the oscillating output signal to generate a feedback oscillating signal;
a phase-frequency comparator powered by a second power supply voltage and configured to compare the feedback oscillating signal to the reference oscillating signal and generate an error signal;
a current source circuit configured to generate a current in response to the error signal, wherein the source voltage of the oscillator circuit is generated in response to said current and wherein a frequency of the oscillating output signal is controlled by said current;
a first multiplexer circuit having a first input configured to receive a reference voltage and a second input configured to receive the source voltage of the oscillator circuit, wherein the first multiplexer circuit selects one of the reference voltage and the source voltage of the oscillator circuit for output as a selected reference voltage;
a first voltage regulator circuit configured to generate the first power supply voltage using the selected reference voltage as a first error amplifier reference voltage;
and
a second voltage regulator circuit configured to generate the second power supply voltage using the reference voltage as a second error amplifier reference voltage.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/696,247Filed 26 Nov 2019 · us provisional application
Priority: 10 Dec 2018
Published: US 2020/0186155 A111 Jun 2020
Granted: 8 Sep 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

H03L 7/0995
Concerning mainly the controlled oscillator of the loop: the oscillator comprising a ring oscillator
H03L 7/08
Using a reference signal applied to a frequency- or phase-locked loop: details of the phase-locked loop
H03L 7/087
Concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal: using at least two…
H03L 7/101
For assuring initial synchronisation or for broadening the capture range: using an additional control signal to the controlled loop oscillator…

Family

Application62/777,446Us provisional application · filed 10 Dec 2018
US 2020/0186155 A1Pre-grant publication · published 11 Jun 2020
US 10,771,073 B2This patent

From the US filing history. Foreign family members aren’t listed.

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