HIGH-PRECISION OSCILLATOR

• US 20150137897A1
• Filed: 08/13/2014
• Published: 05/21/2015
• Est. Priority Date: 11/18/2013
• Status: Active Grant

• Current Assignee: IPGoal Microelectronics (Sichuan) Co., Ltd.
• Original Assignee: IPGoal Microelectronics (Sichuan) Co., Ltd.
• Inventors: Zou, Zhengxian, Sun, Weihong
• Granted Patent: US 9,112,514 B2
• Time in Patent Office: Days
• US Class Current: 331/57
• 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 3/0322 with differential cells
• CPC Class Codes: H03L 1/00 Stabilisation of generator output against variations of physical values, e.g. power supply
• CPC Class Codes: H03L 1/022 by indirect stabilisation, i.e. by generating an electrical correction signal which is a function of the temperature H03L1/021 takes precedence
• CPC Class Codes: H03L 1/04 Constructional details for maintaining temperature constant

Abstract

A high-precision oscillator includes a voltage reference module which includes multiple measured Field Effect Transistors and arranged for detecting process corners for the measured Field Effect Transistors to generate a reference voltage containing process corner information of the measured Field Effect Transistors, a compensation current generating module which is arranged for receiving the reference voltage, making a temperature compensation for the reference voltage, and generating a compensation current which includes both the process compensation and temperature compensation, and a ring oscillator which is arranged for receiving the compensation current and outputting a clock with stable frequency. The high-precision oscillator designs the process compensation and the temperature compensation separately, which are adjustable due to one of them will not be influenced by the other; and frequency of its outputted clock is not influenced by process and temperature, thereby precision of the outputted clock is improved.

Claims

1. A high-precision oscillator, comprising:

a voltage reference module, and the voltage reference module comprising multiple measured Field Effect Transistors and arranged for detecting process corners for the measured Field Effect Transistors to generate a reference voltage which contains process corner information of the measured Field Effect Transistors;

a compensation current generating module, to which the reference voltage is inputted, to provide a temperature compensation for the reference voltage and generate a compensation current which includes both process compensation and temperature compensation; and

a ring oscillator, arranged for receiving the compensation current generated by the compensation current generating module, and then outputting a clock with stable frequency according to the compensation current.

2. The high-precision oscillator according to claim 1, wherein the voltage reference module comprises a first Field Effect Transistor, a second Field Effect Transistor, a third Field Effect Transistor, a fourth Field Effect Transistor, a fifth Field Effect Transistor, a sixth Field Effect Transistor, a seventh Field Effect Transistor, an eighth Field Effect Transistor, a first resistor and a second resistor;

gates and drains of the first Field Effect Transistor, the second Field Effect Transistor and the third Field Effect Transistor are grounded, and a source of the first Field Effect Transistor is connected with a source of the seventh Field Effect Transistor, a source of the second Field Effect Transistor is connected with one terminal of the first resistor, a source of the third Field Effect Transistor is connected with one terminal of the second resistor, and the first Field Effect Transistor, the second Field Effect Transistor and the third Field Effect Transistor are the measured Field Effect Transistors so as to provide the process corner information of the Field Effect Transistors;

sources of the fourth Field Effect Transistor, the fifth Field Effect Transistor and the sixth Field Effect Transistor are connected with an external power source, and their gates are jointly connected to a drain of the fifth Field Effect Transistor, a drain of the fourth Field Effect Transistor is connected with a drain of the seventh Field Effect Transistor, a drain of the fifth Field Effect Transistor is connected with a drain of the eighth Field Effect Transistor, and a drain of the sixth Field Effect Transistor is connected with the other terminal of the second resistor to output the reference voltage;

a gate and a drain of the seventh Field Effect Transistor are connected together which are also connected with a gate of the eighth Field Effect Transistor, and a source of the eighth Field Effect Transistor is connected with the other terminal of the first resistor.

3. The high-precision oscillator according to claim 2, wherein a width/length ratio of the fifth Field Effect Transistor is the same as that of the sixth Field Effect Transistor.

4. The high-precision oscillator according to claim 1, wherein the compensation current generating module comprises a ninth Field Effect Transistor, a tenth Field Effect Transistor, an eleventh Field Effect Transistor, a twelfth Field Effect Transistor, and an operational amplifier;

a gate and a drain of the ninth Field Effect Transistor are grounded, a source of the ninth Field Effect Transistor is connected with an inverting input terminal of the operational amplifier and a source of the tenth Field Effect Transistor respectively; and

a non-inverting input terminal of the operational amplifier is connected with an output terminal of the voltage reference module, and an output terminal of the operational amplifier is connected with a gate of the tenth Field Effect Transistor;

a drain of the tenth Field Effect Transistor, and a drain and a gate of the eleventh Field Effect Transistor are jointly connected to a gate of the twelfth Field Effect Transistor;

sources of the eleventh Field Effect Transistor and the twelfth Field Effect Transistor are connected with the external power source; and

the compensation current which includes both the process compensation and the temperature compensation is outputted from a drain of the twelfth Field Effect Transistor.

5. The high-precision oscillator according to claim 4, wherein the width/length ratio of the eleventh Field Effect Transistor is the same as that of the twelfth Field Effect Transistor.

6. The high-precision oscillator according to claim 2, wherein the compensation current generating module comprises a ninth Field Effect Transistor, a tenth Field Effect Transistor, an eleventh Field Effect Transistor, a twelfth Field Effect Transistor, and an operational amplifier;

a gate and a drain of the ninth Field Effect Transistor are grounded, a source of the ninth Field Effect Transistor is connected with an inverting input terminal of the operational amplifier and a source of the tenth Field Effect Transistor; and

a non-inverting input terminal of the operational amplifier is connected with an output terminal of the voltage reference module, and an output terminal of the operational amplifier is connected with a gate of the tenth Field Effect Transistor;

a drain of the tenth Field Effect Transistor, and a drain and a gate of the eleventh Field Effect Transistor are jointly connected to a gate of the twelfth Field Effect Transistor;

sources of the eleventh Field Effect Transistor and the twelfth Field Effect Transistor are connected with the external power source; and

the compensation current is outputted from a drain of the twelfth Field Effect Transistor; and

the ninth Field Effect Transistor, the first Field Effect Transistor, the second Field Effect Transistor and the third Field Effect Transistor are P-type Field Effect Transistors.

7. The high-precision oscillator according to claim 1, wherein the ring oscillator comprises a thirteenth Field Effect Transistor, a fourteenth Field Effect Transistor, a fifteenth Field Effect Transistor, a comparator and multiple oscillation units;

a drain and a gate of the thirteenth Field Effect Transistor, and a gate of the fourteenth Field Effect Transistor are jointly connected to an output terminal of the compensation current generating module, sources of the thirteenth Field Effect Transistor and the fourteenth Field Effect Transistor are grounded;

a drain of the fourteenth Field Effect Transistor is connected with a drain of the fifteenth Field Effect Transistor;

the drain and a gate of the fifteenth Field Effect Transistor are jointly connected to each oscillation unit, and a source of the fifteenth Field Effect Transistor is connected with the external power source;

all the oscillation units are connected in series in order, and an output terminal of the last oscillation unit is connected with an input terminal of the first oscillation unit, and two output terminals of the last oscillation unit are connected with two input terminals of the comparator respectively, and the clock with stable frequency is outputted from an output terminal of the comparator.