Differential relaxation oscillator reducing noise effect using differential structure and swing booster technology

• US 10,644,682 B2
• Filed: 01/26/2018
• Issued: 05/05/2020
• Est. Priority Date: 01/31/2017
• Status: Active Grant

• Current Assignee: Daegu Gyeongbuk Institute of Science and Technology
• Original Assignee: Daegu Gyeongbuk Institute of Science and Technology
• Inventors: Lee, Jung Hyup, Arup, Kocheethra George, Je, Minkyu
• Primary Examiner(s): Shin, Jeffrey M
• Application Number:
  US15/881,232
• Publication Number:
  US 20180219536A1
• Time in Patent Office: 830 Days
• CPC Class Codes: G06F 1/04 Generating or distributing clock signals or signals derived directly therefrom
• CPC Class Codes: G06F 1/32 Means for saving power
• CPC Class Codes: H03K 3/011 Modifications of generator to compensate for variations in physical values, e.g. voltage, temperature to maintain energy constant H03K3/015
• CPC Class Codes: H03K 3/012 Modifications of generator to improve response time or to decrease power consumption
• CPC Class Codes: H03K 3/013 Modifications of generator to prevent operation by noise or interference
• CPC Class Codes: H03K 3/0231 Astable circuits H03K3/0315 takes precedence
• CPC Class Codes: H03K 4/501 the starting point of the flyback period being determined by the amplitude of the voltage across the capacitor, e.g. by a comparator

Abstract

Disclosed is a differential relaxation oscillator using a differential structure that may stably maintain a differential voltage swing of capacitors despite an influence of an offset voltage and 1/f noise of a comparator, and also generate a dynamic current only at a point in time at which switching is performed, thereby minimizing power consumption.

Claims

1. A differential relaxation oscillator comprising:

a differential swing booster configured to switch a plurality of capacitors to connect to a direct current (DC) power supply or a ground electrode based on a switching period; and

a comparator configured to adjust the switching period by comparing a voltage of each of the capacitors to a preset threshold voltage,

wherein the differential swing booster is connected to the DC power supply or a ground electrode and switch the capacitors to connect to the DC power supply or the ground electrode such that a voltage difference between the capacitors is greater than or equal to a voltage of the DC power supply in each switching period;

wherein the comparator comprises a clock generator configured to generate a clock signal to adjust the switching period using the voltage of each of the capacitors, at a point in time at which the voltage of each of the capacitors is equal to the threshold voltage.

2. The differential relaxation oscillator of claim 1, wherein the clock generator comprises:

an inverter configured to generate the clock signal by inverting the voltage of each of the capacitors when a current is applied at the point in time at which the voltage of each of the capacitors is equal to the threshold voltage.

3. The differential relaxation oscillator of claim 2, wherein the comparator comprises:

a bias voltage generator configured to generate a bias voltage to be applied to a gate electrode of a transistor connected to the inverter based on an operating point of the inverter.

4. The differential relaxation oscillator of claim 1, wherein the differential swing booster comprises:

a switch configured to alternately connect each of the capacitors to the DC power supply or the ground electrode based on the clock signal.

5. The differential relaxation oscillator of claim 1, wherein, when the comparator combines an offset voltage with the voltage of each of the capacitors, the capacitors are configured to be charged based on the offset voltage before being switched to connect to the DC power supply or the ground electrode based on the switching period.