CN220067385U

CN220067385U - High-precision oscillator circuit

Info

Publication number: CN220067385U
Application number: CN202321691384.7U
Authority: CN
Inventors: 梁佩俊; 仝志军; 孙占龙
Original assignee: Shenzhen Meisi Micro Semiconductor Co ltd
Current assignee: Shenzhen Meisi Micro Semiconductor Co ltd
Priority date: 2023-06-30
Filing date: 2023-06-30
Publication date: 2023-11-21
Anticipated expiration: 2033-06-30

Abstract

The utility model discloses a high-precision oscillator circuit, which comprises a reference voltage circuit, a voltage stabilizing circuit, a reference current circuit and an RC oscillation circuit, wherein the reference voltage circuit provides a reference voltage V-ref for the high-precision oscillator circuit, the voltage stabilizing circuit is electrically connected with the reference voltage circuit and provides a stable Vout voltage for the high-precision oscillator circuit, the reference current circuit is electrically connected with the voltage stabilizing circuit and provides reference currents ib-ref, ib1 and ib2 for the high-precision oscillator circuit, and the RC oscillation circuit is electrically connected with the voltage stabilizing circuit and the reference current circuit and is used for generating high-precision oscillation output.

Description

High-precision oscillator circuit

Technical Field

The present utility model relates to the field of semiconductor integrated circuits, and more particularly, to a high-precision oscillator circuit.

Background

The semiconductor integrated circuit includes an oscillator circuit therein, but in actual operation, a power supply coefficient, a temperature coefficient, and a process parameter have an important influence on the accuracy of the oscillator circuit. How to develop a high-precision oscillator circuit, and in particular how to eliminate the influence of temperature coefficient on the oscillator circuit is a common concern for technicians in the industry.

Disclosure of Invention

Aiming at the defects in the prior art, the utility model discloses a high-precision oscillator circuit, which comprises a positive temperature coefficient compensation resistor and a negative temperature coefficient compensation resistor, wherein the influence of ambient temperature on the oscillator circuit can be eliminated under the action of the positive temperature coefficient compensation resistor and the negative temperature coefficient compensation resistor, so that the precision of the oscillator circuit is improved, and the technical scheme of the utility model is as follows:

a high-precision oscillator circuit comprises a reference voltage circuit, a voltage stabilizing circuit, a reference current circuit and an RC oscillating circuit.

Specifically:

the reference voltage circuit provides a reference voltage V-ref for the high precision oscillator circuit.

The voltage stabilizing circuit is electrically connected with the reference voltage circuit and provides stable Vout voltage for the high-precision oscillator circuit.

The reference current circuit is electrically connected with the voltage stabilizing circuit and provides reference currents ib-ref, ib1 and ib2 for the high-precision oscillator circuit.

The RC oscillation circuit is electrically connected with the voltage stabilizing circuit and the reference current circuit and is used for generating high-precision oscillation output.

Further, the reference voltage circuit includes a first PMOS transistor MP1, a second PMOS transistor MP2, a third PMOS transistor MP3, a first NMOS transistor MN1, a second NMOS transistor MN2, a third NMOS transistor MN3, a first resistor R1, and a second resistor R2.

Specifically, the source electrode of the first PMOS transistor MP1 is connected to the substrate by a VDD power supply, the drain electrode is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the drain electrode of the first NMOS transistor MN1, the source electrode of the first NMOS transistor MN1 is grounded to the substrate, and the gate electrode of the first NMOS transistor MN1 is connected to the drain electrode of the first PMOS transistor MP 1.

The source electrode of the second PMOS tube MP2 is connected with the substrate through a VDD power supply, the drain electrode of the second NMOS tube MN2 is connected with the drain electrode of the second NMOS tube MN2, the grid electrodes of the first PMOS tube MP1 and the second PMOS tube MP2 are connected with the drain electrode of the second PMOS tube MP2, the grid electrode of the second NMOS tube MN2 is connected with the drain electrode of the first NMOS tube MN1, and the source electrode of the second NMOS tube MN2 is grounded with the substrate.

The source electrode of the third PMOS tube MP3 is connected with the substrate by a VDD power supply, the grid electrode of the third PMOS tube MP3 is connected with the drain electrode of the second PMOS tube MP2, the drain electrode of the third PMOS tube MP3 is connected with one end of the second resistor R2, the other end of the second resistor R2 is connected with the drain electrode of the third NMOS tube MN3, the grid electrode of the third NMOS tube MN3 is connected with the drain electrode, and the source electrode of the third NMOS tube MN3 is grounded with the substrate.

In this technical scheme, the common end of the third PMOS MP3 and the second resistor R2 is the output end of the reference voltage V-ref.

Further, the voltage stabilizing circuit includes an operational amplifier AMP, a third resistor R3 and a fourth resistor R4.

The positive electrode input end of the operational amplifier AMP is connected with the reference voltage V-ref, the output end of the operational amplifier AMP is connected with one end of the third resistor R3, the other end of the third resistor R3 is connected with one end of the fourth resistor R4, the other end of the fourth resistor R4 is grounded, and the negative electrode input end of the operational amplifier AMP is connected with a common end of the third resistor R3 and the fourth resistor R4.

In this technical scheme, the output end of the operational amplifier AMP is a Vout voltage output end.

Further, the reference current circuit includes a fourth PMOS transistor MP4, a fifth PMOS transistor MP5, a sixth PMOS transistor MP6, a first capacitor C1, and a fifth resistor R5.

The source electrode of the fourth PMOS tube MP4 is connected with the substrate by Vout voltage, the grid electrode of the fourth PMOS tube MP4 is connected with the drain electrode, the drain electrode of the fourth PMOS tube MP4 is also connected with one end of the fifth resistor R5, and the other end of the fifth resistor R5 is grounded.

One end of the first capacitor C1 is connected to Vout voltage, and the other end of the first capacitor C1 is connected to the gate of the fourth PMOS MP 4.

The source electrode of the fifth PMOS tube MP5 is connected with the substrate by Vout voltage, and the grid electrode of the fifth PMOS tube MP5 is connected with the grid electrode of the fourth PMOS tube MP 4.

The source electrode of the sixth PMOS tube MP6 is connected with the substrate by Vout voltage, and the grid electrode of the sixth PMOS tube MP6 is connected with the grid electrode of the fifth PMOS tube MP 5.

The gate terminals of the fourth PMOS tube MP4 and the fifth PMOS tube MP5 are the output terminals of the reference current ib-ref.

The drain electrode of the fifth PMOS transistor MP5 is the output end of the reference current ib1.

The drain electrode of the sixth PMOS transistor MP6 is the output end of the reference current ib2.

Further, the RC oscillating circuit includes a first comparator U1, a second comparator U2, a first nor gate N1, a second nor gate N2, a first inverter I1, a second inverter I2, a second capacitor C2, a third capacitor C3, a sixth resistor R6, a seventh resistor R7, a fourth NMOS MN4, and a fifth NMOS MN5.

Specifically, the positive input ends of the first comparator U1 and the second comparator U2 are connected to the reference current ib-ref, the negative input end of the first comparator U1 is connected to the reference current ib1, and the negative input end of the second comparator U2 is connected to the reference current ib2.

The output end of the first comparator U1 is connected with the first input end of the first NOR gate N1, the output end of the second comparator U2 is connected with the first input end of the second NOR gate N2, the second input end of the first NOR gate N1 is connected with the output end of the second NOR gate N2, and the second input end of the second NOR gate N2 is connected with the output end of the first NOR gate N1.

The input end of the first inverter I1 is connected with the output end of the second NOR gate N2, and the output end of the first inverter I1 is connected with the input end of the second inverter I2.

One end of the second capacitor C2 is connected to Vout voltage, the other end is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is connected to the drain of the fourth NMOS transistor MN4, the gate of the fourth NMOS transistor MN4 is connected to the input end of the first inverter I1, and the source of the fourth NMOS transistor MN4 is grounded to the substrate.

One end of the third capacitor C3 is connected to Vout voltage, the other end is connected to one end of the seventh resistor R7, the other end of the seventh resistor R7 is connected to the drain of the fifth NMOS transistor MN5, the gate of the fifth NMOS transistor MN5 is connected to the output end of the first inverter I1, and the source of the fifth NMOS transistor MN5 is grounded to the substrate.

In this technical scheme, the common terminal of the second capacitor C2 and the sixth resistor R6 is connected to the reference current ib1.

The common terminal of the third capacitor C3 and the seventh resistor R7 is connected to the reference current ib2.

The output end of the second inverter I2 is the output end of the high-precision oscillator circuit.

The high-precision oscillator circuit comprises the positive temperature coefficient compensation resistor and the negative temperature coefficient compensation resistor, and can eliminate the influence of the ambient temperature on the oscillator circuit under the action of the positive temperature coefficient compensation resistor and the negative temperature coefficient compensation resistor.

Drawings

Fig. 1 is a schematic diagram of a high-precision oscillator circuit according to the present utility model.

Fig. 2 is a schematic circuit diagram of a reference voltage circuit in a high-precision oscillator circuit according to the present utility model.

Fig. 3 is a schematic circuit diagram of a voltage stabilizing circuit in a high-precision oscillator circuit according to the present utility model.

Fig. 4 is a schematic circuit diagram of a reference current circuit in a high-precision oscillator circuit according to the present utility model.

Fig. 5 is a schematic circuit diagram of an RC oscillating circuit in a high-precision oscillator circuit according to the present utility model.

Description of the embodiments

The utility model is described in further detail below with reference to the accompanying drawings.

For the purpose of better illustrating the embodiments, certain elements of the drawings may be omitted, enlarged or reduced and do not represent the actual product dimensions; some well known structures in the drawings and omission of the description thereof will be understood by those skilled in the art. The same or similar reference numerals correspond to the same or similar components.

The function within the oscillator circuit semiconductor integrated circuit is critical, and its accuracy directly affects the stability and accuracy of the system. The precision of the oscillator circuit is easily affected by the environment and the electrical parameters of the device, and how to avoid the influence of these factors is a technical problem that needs to be solved by the technicians.

In view of the prior art, the utility model discloses a high-precision oscillator circuit, which comprises a positive temperature coefficient compensation resistor and a negative temperature coefficient compensation resistor, wherein the influence of the ambient temperature on the oscillator circuit can be eliminated under the action of the positive temperature coefficient compensation resistor and the negative temperature coefficient compensation resistor, and the technical scheme is applicable to the ambient temperature of minus 40-70 ℃. Specifically, as the temperature changes, the positive and negative temperature coefficient compensation resistors change, so that the charge and discharge time of the capacitor in the RC oscillator circuit changes, but the sum of the charge and discharge time is unchanged in the same charge and discharge period, so that the output frequency of the RC oscillator circuit is very stable, and high-precision oscillation output is achieved.

In addition, the capacitive power supply coefficient, the technological parameters of the resistor and the capacitor and the like can be effectively improved in the technical scheme.

Specific embodiments of the utility model are as follows:

as shown in fig. 1, the high-precision oscillator circuit of the present embodiment includes a reference voltage circuit 1, a voltage stabilizing circuit 2, a reference current circuit 3, and an RC oscillating circuit 4.

In this embodiment, the reference voltage circuit 1 provides the reference voltage V-ref for the high precision oscillator circuit.

The voltage stabilizing circuit 2 is electrically connected with the reference voltage circuit 1 and provides stable Vout voltage for the high-precision oscillator circuit.

The reference current circuit 3 is electrically connected to the voltage stabilizing circuit 2, and provides reference currents ib-ref, ib1 and ib2 for the high-precision oscillator circuit.

The RC oscillation circuit 4 is electrically connected with the voltage stabilizing circuit 2 and the reference current circuit 3 and is used for generating high-precision oscillation output.

In this embodiment, as shown in fig. 2, the reference voltage circuit 1 includes a first PMOS transistor MP1, a second PMOS transistor MP2, a third PMOS transistor MP3, a first NMOS transistor MN1, a second NMOS transistor MN2, a third NMOS transistor MN3, a first resistor R1, and a second resistor R2.

It should be noted that, in the present embodiment, the common terminal of the third PMOS transistor MP3 and the second resistor R2 is the output terminal of the reference voltage V-ref.

In this embodiment, as shown in fig. 3, the voltage stabilizing circuit 2 includes an operational amplifier AMP, a third resistor R3 and a fourth resistor R4.

Specifically, the positive input end of the operational amplifier AMP is connected to the reference voltage V-ref, the output end of the operational amplifier AMP is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is grounded, and the negative input end of the operational amplifier AMP is connected to the common end of the third resistor R3 and the fourth resistor R4.

It should be noted that the output terminal of the operational amplifier AMP in this embodiment is the Vout voltage output terminal.

In this embodiment, as shown in fig. 4, the reference current circuit 3 includes a fourth PMOS transistor MP4, a fifth PMOS transistor MP5, a sixth PMOS transistor MP6, a first capacitor C1, and a fifth resistor R5.

It should be noted that the fifth resistor R5 is a negative temperature coefficient compensation resistor.

Specifically, the source electrode of the fourth PMOS transistor MP4 is connected to the substrate by Vout voltage, the gate electrode of the fourth PMOS transistor MP4 is connected to the drain electrode, the drain electrode of the fourth PMOS transistor MP4 is further connected to one end of the fifth resistor R5, and the other end of the fifth resistor R5 is grounded.

It should be noted that, in the present embodiment, the gate terminals of the fourth PMOS transistor MP4 and the fifth PMOS transistor MP5 are the output terminals of the reference currents ib-ref.

The drain of the fifth PMOS transistor MP5 in this embodiment is the output terminal of the reference current ib1.

The drain of the sixth PMOS transistor MP6 in this embodiment is the output terminal of the reference current ib2.

In this embodiment, as shown in fig. 5, the RC oscillating circuit 4 includes a first comparator U1, a second comparator U2, a first nor gate N1, a second nor gate N2, a first inverter I1, a second inverter I2, a second capacitor C2, a third capacitor C3, a sixth resistor R6, a seventh resistor R7, a fourth NMOS transistor MN4 and a fifth NMOS transistor MN5.

It should be noted that the sixth resistor R6 and the seventh resistor R7 are positive temperature coefficient compensation resistors.

It should be noted that the output terminal of the second inverter I2 in this embodiment is the output terminal of the high-precision oscillator circuit.

The temperature range of the external environment suitable for the embodiment is wide, and the applicable range is-40-70 ℃.

The specific principle of this embodiment is as follows:

the total charge and discharge time of the second capacitor C2 and the third capacitor C3 is T1, the discharge time is T2, and t=t1+t2.

When the external environment temperature decreases, the resistance of the negative temperature coefficient compensation resistor fifth resistor R5 in the reference current circuit 3 increases, the reference currents ib1 and ib2 decrease, the resistance of the positive temperature coefficient compensation resistor sixth resistor R6 and the resistance of the seventh resistor R7 in the RC oscillating circuit 4 decrease, the charging time T1 temperature drop of the second capacitor C2 and the third capacitor C3 increases, the discharging time T2 temperature drop decreases, and at this time, T temperature drop=t1 temperature drop+t2 temperature drop.

When the external environment temperature rises, the resistance of the negative temperature coefficient compensation resistor fifth resistor R5 in the reference current circuit 3 decreases, the reference currents ib1 and ib2 increase, the resistance of the positive temperature coefficient compensation resistor sixth resistor R6 and the resistance of the seventh resistor R7 in the RC oscillating circuit 4 increase, the charging time T1 of the second capacitor C2 and the third capacitor C3 increases, the discharging time T2 increases, and at the moment, the T temperature rise=t1 temperature rise+t2 temperature rise.

Because the positive and negative temperature coefficient compensation function ensures that the sum of charge and discharge time is unchanged in the same charge and discharge period, T1 temperature drop+t2 temperature drop=t1 temperature rise+t2 temperature rise=t temperature drop=t temperature rise, so that the output frequency of the RC oscillator circuit is very consistent and stable, and high-precision oscillation output is achieved.

It is to be understood that the above examples of the present utility model are provided by way of illustration only and not by way of limitation of the embodiments of the present utility model. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the utility model are desired to be protected by the following claims.

Claims

1. A high precision oscillator circuit comprising:

a reference voltage circuit for providing a reference voltage V-ref for the high-precision oscillator circuit;

the voltage stabilizing circuit is electrically connected with the reference voltage circuit and provides stable Vout voltage for the high-precision oscillator circuit;

the reference current circuit is electrically connected with the voltage stabilizing circuit and provides reference currents ib-ref, ib1 and ib2 for the high-precision oscillator circuit;

and the RC oscillation circuit is electrically connected with the voltage stabilizing circuit and the reference current circuit and is used for generating high-precision oscillation output.

2. The high-precision oscillator circuit of claim 1, wherein the reference voltage circuit comprises a first PMOS transistor MP1, a second PMOS transistor MP2, a third PMOS transistor MP3, a first NMOS transistor MN1, a second NMOS transistor MN2, a third NMOS transistor MN3, a first resistor R1, and a second resistor R2;

the source electrode and the substrate of the first PMOS tube MP1 are connected with a VDD power supply, the drain electrode is connected with one end of the first resistor R1, the other end of the first resistor R1 is connected with the drain electrode of the first NMOS tube MN1, the source electrode and the substrate of the first NMOS tube MN1 are grounded, and the grid electrode of the first NMOS tube MN1 is connected with the drain electrode of the first PMOS tube MP 1;

the source electrode of the second PMOS tube MP2 is connected with the substrate by a VDD power supply, the drain electrode of the second NMOS tube MN2 is connected with the drain electrode of the second NMOS tube MN2, the grid electrodes of the first PMOS tube MP1 and the second PMOS tube MP2 are connected with the drain electrode of the second PMOS tube MP2, the grid electrode of the second NMOS tube MN2 is connected with the drain electrode of the first NMOS tube MN1, and the source electrode of the second NMOS tube MN2 is grounded with the substrate;

the source electrode of the third PMOS tube MP3 is connected with the substrate by a VDD power supply, the grid electrode of the third PMOS tube MP3 is connected with the drain electrode of the second PMOS tube MP2, the drain electrode of the third PMOS tube MP3 is connected with one end of the second resistor R2, the other end of the second resistor R2 is connected with the drain electrode of the third NMOS tube MN3, the grid electrode of the third NMOS tube MN3 is connected with the drain electrode, and the source electrode of the third NMOS tube MN3 is grounded with the substrate;

the common end of the third PMOS tube MP3 and the second resistor R2 is the output end of the reference voltage V-ref.

3. The high-precision oscillator circuit according to claim 1, wherein the voltage stabilizing circuit comprises an operational amplifier AMP, a third resistor R3 and a fourth resistor R4;

the positive electrode input end of the operational amplifier AMP is connected with a reference voltage V-ref, the output end of the operational amplifier AMP is connected with one end of the third resistor R3, the other end of the third resistor R3 is connected with one end of the fourth resistor R4, the other end of the fourth resistor R4 is grounded, and the negative electrode input end of the operational amplifier AMP is connected with a common end of the third resistor R3 and the fourth resistor R4;

the output end of the operational amplifier AMP is Vout voltage output end.

4. The high-precision oscillator circuit as claimed in claim 1, wherein the reference current circuit comprises a fourth PMOS transistor MP4, a fifth PMOS transistor MP5, a sixth PMOS transistor MP6, a first capacitor C1 and a fifth resistor R5;

the source electrode of the fourth PMOS tube MP4 is connected with the substrate by Vout voltage, the grid electrode of the fourth PMOS tube MP4 is connected with the drain electrode, the drain electrode of the fourth PMOS tube MP4 is also connected with one end of the fifth resistor R5, and the other end of the fifth resistor R5 is grounded;

one end of the first capacitor C1 is connected with Vout voltage, and the other end of the first capacitor C1 is connected with the grid electrode of the fourth PMOS tube MP 4;

the source electrode of the fifth PMOS tube MP5 is connected with the substrate by Vout voltage, and the grid electrode of the fifth PMOS tube MP5 is connected with the grid electrode of the fourth PMOS tube MP 4;

the source electrode of the sixth PMOS tube MP6 is connected with the substrate by Vout voltage, and the grid electrode of the sixth PMOS tube MP6 is connected with the grid electrode of the fifth PMOS tube MP 5;

the gate terminals of the fourth PMOS tube MP4 and the fifth PMOS tube MP5 are the output terminals of the reference current ib-ref;

the drain electrode of the fifth PMOS tube MP5 is the output end of the reference current ib1;

5. The high-precision oscillator circuit as claimed in claim 1, wherein the RC oscillating circuit comprises a first comparator U1, a second comparator U2, a first nor gate N1, a second nor gate N2, a first inverter I1, a second inverter I2, a second capacitor C2, a third capacitor C3, a sixth resistor R6, a seventh resistor R7, a fourth NMOS transistor MN4 and a fifth NMOS transistor MN5;

the positive input ends of the first comparator U1 and the second comparator U2 are connected with the reference current ib-ref, the negative input end of the first comparator U1 is connected with the reference current ib1, and the negative input end of the second comparator U2 is connected with the reference current ib2;

the output end of the first comparator U1 is connected with the first input end of the first NOR gate N1, the output end of the second comparator U2 is connected with the first input end of the second NOR gate N2, the second input end of the first NOR gate N1 is connected with the output end of the second NOR gate N2, and the second input end of the second NOR gate N2 is connected with the output end of the first NOR gate N1;

the input end of the first inverter I1 is connected with the output end of the second NOR gate N2, and the output end of the first inverter I1 is connected with the input end of the second inverter I2;

one end of the second capacitor C2 is connected to Vout voltage, the other end is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is connected to the drain of the fourth NMOS transistor MN4, the gate of the fourth NMOS transistor MN4 is connected to the input end of the first inverter I1, and the source of the fourth NMOS transistor MN4 is grounded to the substrate;

one end of the third capacitor C3 is connected to Vout voltage, the other end is connected to one end of the seventh resistor R7, the other end of the seventh resistor R7 is connected to the drain of the fifth NMOS transistor MN5, the gate of the fifth NMOS transistor MN5 is connected to the output end of the first inverter I1, and the source of the fifth NMOS transistor MN5 is grounded to the substrate;

the common end of the second capacitor C2 and the sixth resistor R6 is connected to the reference current ib1;

the common end of the third capacitor C3 and the seventh resistor R7 is connected to the reference current ib2;