Rc time based locked voltage controlled oscillator

Patent metadata

Field	Value
Publication number	US-12095420-B2
Application number	US-202318322077-A
Country	US
Kind code	B2
Filing date	May 23, 2023
Priority date	Jul 15, 2020
Publication date	Sep 17, 2024
Grant date	Sep 17, 2024

Abstract

Circuits and processes for locking a voltage-controlled oscillator (VCO) at a high frequency signal are described. A circuit may include a voltage-controlled oscillator configured to generate a high frequency signal based on a control signal, a dummy load parallel to the voltage-controlled oscillator and configured to receive the control signal via a switch, and a digital-to-analog converter coupled to the voltage-controlled oscillator where the control signal is generated based on an output of the digital-to-analog converter.

First claim

What is claimed is:

1. A circuit, comprising:
a voltage-controlled oscillator configured to generate a high frequency signal based on a control signal;
a dummy load parallel to the voltage-controlled oscillator and configured to receive the control signal via a switch, the dummy load being configured to dissipate energy in the control signal when the voltage-controlled oscillator is in an OFF state; and
a digital-to-analog converter coupled to the voltage-controlled oscillator, the control signal being generated based on an output of the digital-to-analog converter.

2. The circuit of claim 1 , wherein the output of the digital-to-analog converter is an adjustment signal.

3. The circuit of claim 1 , further comprising:
a digital filter coupled to the voltage-controlled oscillator and configured to receive the high frequency signal, the digital-to-analog converter configured to output an adjustment signal based on a data signal from the digital filter.

4. A circuit, comprising:
a voltage-controlled oscillator configured to generate a high frequency signal based on a control signal:
a dummy load parallel to the voltage-controlled oscillator and configured to receive the control signal via a first switch;
a digital-to-analog converter coupled to the voltage-controlled oscillator, the control signal being generated based on an output of the digital-to-analog converter; and
a second switch disposed between the voltage-controlled oscillator and the digital-to-analog converter.

5. The circuit of claim 4 , wherein the voltage-controlled oscillator is switchably coupled within a timing circuit.

6. A circuit, comprising:
a voltage-controlled oscillator configured to generate a high frequency signal based on a control signal;
a dummy load parallel to the voltage-controlled oscillator and configured to receive the control signal via a switch; and
a digital-to-analog converter coupled to the voltage-controlled oscillator, the control signal being generated based on an output of the digital-to-analog converter, the voltage-controlled oscillator being switchably coupled within a feedback loop with the digital-to-analog converter.

7. The circuit of claim 6 , further comprising:
an adjustable current converter coupled, at an input terminal, to a power source and configured to generate the control signal, the adjustable current converter configured to adjust the control signal based on an adjustment signal received from the digital-to-analog converter.

8. The circuit of claim 1 , wherein the voltage-controlled oscillator is included in a timing circuit, and is configured to output the high frequency signal while the timing circuit is enabled.

9. An apparatus, comprising:
a voltage-controlled oscillator included in a timing circuit and configured to generate a high frequency signal based on a control signal;
a dummy load switchably coupled within the timing circuit; and
a digital-to-analog converter coupled to the voltage-controlled oscillator and configured to cause an adjustment of the control signal, the voltage-controlled oscillator having an impedance substantially equal to an impedance of the dummy load.

10. The apparatus of claim 9 , wherein the voltage-controlled oscillator is switchably coupled within a feedback loop with the digital-to-analog converter.

11. An apparatus, comprising:
a voltage-controlled oscillator included in a timing circuit and configured to generate a high frequency signal based on a control signal;
a dummy load switchably coupled within the timing circuit;
a digital-to-analog converter coupled to the voltage-controlled oscillator and configured to cause an adjustment of the control signal; and
a digital filter configured to transmit a switching signal to the voltage-controlled oscillator and the dummy load.

12. The apparatus of claim 11 , wherein the voltage-controlled oscillator is configured to provide a voltage-controlled oscillator impedance to the control signal while the dummy load is configured to provide a dummy load impedance to the control signal.

13. The apparatus of claim 9 , further comprising:
a digital filter coupled to the voltage-controlled oscillator and configured to receive the high frequency signal, the digital filter including:
a ripple counter configured to receive the high frequency signal; and
a logic control circuit configured to output a switching signal that drives the voltage-controlled oscillator and the dummy load.

14. The apparatus of claim 9 , wherein the voltage-controlled oscillator is configured to generate the high frequency signal with a specified period.

15. The apparatus of claim 9 , wherein digital filter is configured to:
divide the high frequency signal to generate a low frequency signal;
count a number of pulses in the low frequency signal until an overflow condition is satisfied; and
output an overflow signal to a logic control circuit in response to the overflow condition being satisfied.

16. A method, comprising:
enabling a voltage-controlled oscillator within a timing circuit to receive a control signal, the voltage-controlled oscillator configured to generate a high frequency signal based on the control signal;
switchably disconnecting a dummy load within the timing circuit such that the dummy load is isolated from the control signal;
adjusting the control signal using a digital-to-analog converter coupled to the voltage-controlled oscillator;
switchably disconnecting the voltage-controlled oscillator such that the voltage-controlled oscillator is isolated from the control signal; and
enabling the dummy load to receive the control signal such that the dummy load dissipates energy in the control signal.

17. The method of claim 16 , further comprising:
modifying, by the voltage-controlled oscillator, a center frequency of the high frequency signal in response to the adjusting the control signal.

Assignees

• Semiconductor Components Ind Llc

Inventors

• Plojhar Jan
• Vander Voorde Lucas Emiel Elie
• Mares Pavel

Classifications

• H03L7/00

  Automatic control of frequency or phase; Synchronisation · CPC title

• H03B5/1293

  having means for achieving a desired tuning characteristic, e.g. linearising the frequency characteristic across the tuning voltage range · CPC title

• H03B5/129

  the parameter being a bias voltage or a power supply · CPC title

• H03B5/1271

  the frequency being controlled by a control current, i.e. current controlled oscillators · CPC title

• H03K5/00006 Primary

  Changing the frequency (modulating pulses H03K7/00; frequency dividers H03K21/00 - H03K29/00; additive or subtractive mixing of two pulse rates into one G06F7/605; pulse rate dividers G06F7/68) · CPC title