Oscillator and method for operating an oscillator

• US 10,659,012 B1
• Filed: 11/08/2018
• Issued: 05/19/2020
• Est. Priority Date: 11/08/2018
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Zhang, Xu
• Primary Examiner(s): Gannon, Levi
• Application Number:
  US16/184,871
• Publication Number:
  US 20200153417A1
• Time in Patent Office: 558 Days
• Field of Search: 331 57
• CPC Class Codes: H03B 2200/0094 Measures to ensure starting of oscillations
• CPC Class Codes: H03K 19/017509 Interface arrangements
• CPC Class Codes: H03K 3/012 Modifications of generator to improve response time or to decrease power consumption
• CPC Class Codes: H03K 3/0315 Ring oscillators
• CPC Class Codes: H03L 3/00 Starting of generators

Abstract

Embodiments of an oscillator and a method of operating an oscillator are disclosed. In an embodiment, an oscillator can include a ring oscillator core, a control circuit, and a timer that coordinates timing of the control circuit to avoid a current resulting from a voltage level associated with an output of the ring oscillator core during a startup and to allow the ring oscillator core to operate with a low startup current and a low operational power.

Claims

1. An oscillator, comprising:

an output;

a ring oscillator core configured to generate an output clock signal on the output;

a control circuit coupled between the output and the ring oscillator core; and

a timer that disables the control circuit until oscillation of the ring oscillator core begins;

wherein the timer is released by a reset signal; and

wherein after a release of the timer by the reset signal, the timer expires and activates the control circuit after a startup time of the ring oscillator core.

2. The oscillator of claim 1

wherein the control circuit is electronically coupled between the ring oscillator core and the timer.

3. The oscillator of claim 1

wherein said ring oscillator core includes a current-controlled oscillator core.

4. The oscillator of claim 1 wherein said control circuit includes a level shifter.

5. The oscillator of claim 1 wherein said timer includes an analog timer.

6. The oscillator of claim 1 wherein said timer includes a digital timer.

7. The oscillator of claim 1:

wherein the output is configured to be coupled to a set of loading stages that are configured to draw a current from the output clock signal; and

wherein said current includes a short-through current.

8. A method of operating an oscillator, comprising:

coordinating a control circuit with a timer

to avoid a current resulting from a voltage level associated with an output of a ring oscillator core during a startup phase and

to allow the ring oscillator core to operate with a low startup current and a low operational power; and

releasing the timer by a reset signal;

wherein after the reset signal releases the timer, the timer expires and activates the control circuit after a startup time of the ring oscillator core.

9. The method of claim 8 further comprising

gating the control circuit by the timer so as to disable the control circuit when the ring oscillator core is not oscillating such that the current from at least one of the control circuit and clock loading stages associated with the timer is avoided.

10. The method of claim 8

wherein the control circuit is electronically connected to the ring oscillator core and the timer at an interface between the ring oscillator core and the timer.

11. The method of claim 8

wherein said ring oscillator core comprises a current-controlled oscillator core.

12. The method of claim 8 wherein said control circuit comprises a level shifter.

13. The method of claim 8 wherein said timer comprises at least one of an analog timer and a digital timer.

14. An oscillator, comprising:

an output;

a current-controlled oscillator core configured to generate an output clock signal on the output;

a level shifter coupled between the output and the current-controlled oscillator core; and

a timer that disables the level shifter until oscillation of the current-controlled oscillator core begins;

wherein the timer is released by a reset signal; and

wherein after a release of the timer by the reset signal, the timer expires and activates the level shifter after a startup time of the current-controlled oscillator core.

15. The oscillator of claim 14:

wherein the output is configured to be coupled to a set of loading stages that are configured to draw a current from the output clock signal;

wherein the current includes a short-through current; and

wherein the disabled level shifter is configured to block the short-through current.

16. An oscillator, comprising:

a ring oscillator core;

a control circuit;

a timer that coordinates timing of the control circuit,

to avoid a current resulting from a voltage level associated with an output of the ring oscillator core during a startup; and

to allow the ring oscillator core to operate with a low startup current and a low operational power;

wherein the timer is released by a reset signal; and

wherein after a release of the timer by the reset signal, the timer expires and activates the control circuit after a startup time of the ring oscillator core.