CN205584151U - A New High Precision RC Oscillator Circuit - Google Patents

Abstract

The utility model discloses a novel high accuracy RC oscillator circuit, but including operational amplifier and configuration register, operational amplifier's non inverting input end is connected with reference voltage source, and operational amplifier's output is connected with the mirror image circuit, and the non inverting input end of mirror image circuit is connected with the standard voltage source, and the inverting input end is connected with the voltage -current conversion ware, and the output of voltage -current conversion ware is connected with two limit comparator circuits, a hysteresis comparator's of two limit comparator circuits inverting terminal and the 2nd hysteresis comparator's syntropy end all are connected to reference voltage source, and a hysteresis comparator's non inverting input end is connected with RC charging and discharging circuit, the 2nd hysteresis comparator's reverse input end ground connection, and the output of two limit comparator circuits is connected with the RS trigger, but configuration register is connected with the digit accent and repaiies the circuit, and the digit is transferred and is repaiied circuit connection between the output of mirror image circuit, still be connected with the temperature compensating MOS pipe between two MOS of the input pipe of mirror image circuit.

Description

A New High Precision RC Oscillator Circuit

technical field

The utility model relates to the technical field of integrated stoves, in particular to a novel high-precision RC oscillator circuit.

Background technique

The clock signal has become an essential part in large-scale digital integrated circuits. In the design of these digital system circuits, there are three commonly used clock generation circuits: Rc oscillator, ring oscillator and crystal oscillator. The RC oscillator is the most commonly used oscillator circuit. In comparison, the RC oscillator has the advantages of short start-up time, easy frequency adjustment, and easy design and manufacture using ordinary CMOS integrated circuit technology. However, it also has the disadvantages of poor oscillation frequency stability, the generated frequency is greatly affected by the power supply voltage, ambient temperature, and the electrical characteristics of various components that make up the oscillator, and the accuracy is poor.

Utility model content

In view of the above problems, the utility model provides a new type of high-precision RC oscillator circuit, which has a mechanism for digitally adjusting the frequency and a temperature compensation design, so that it is less sensitive to voltage, temperature and process deviation, and effectively Eliminating the error caused by the hysteresis of the comparator to provide a stable and accurate clock signal can effectively solve the problems in the background technology.

In order to achieve the above object, the utility model provides the following technical solutions: a novel high-precision RC oscillator circuit, including an operational amplifier and a configurable register, the non-inverting input of the operational amplifier is connected with a reference voltage source, and the output terminal of the operational amplifier A mirror circuit is connected, and the inverting input terminal is also connected to the near-ground terminal of the mirror circuit through a wire. The non-inverting input terminal of the mirror circuit is connected to a standard voltage source, and the inverting input terminal is connected to a voltage-current converter, and the voltage-current conversion The output terminal of the device is connected with a double-limit comparator circuit and an RC charging and discharging circuit;

The dual-limit comparator circuit includes a first hysteresis comparator and a second hysteresis comparator, the inverting terminal of the first hysteresis comparator and the non-inverting terminal of the second hysteresis comparator are connected to a reference voltage source, and the first hysteresis comparator The non-inverting input end of the comparator is connected with an RC charging and discharging circuit, the inverting input end of the second hysteresis comparator is grounded, and the output end of the double-limit comparator circuit is connected with an RS flip-flop; the configurable register is connected with a digital adjustment circuit, A digital trim circuit is connected between the output terminals of the mirror circuit.

As a preferred technical solution of the utility model, the S end of the RS flip-flop is connected to the output end of the first hysteresis comparator, the R end is connected to the output end of the second hysteresis comparator, and the non-inverting output end of the RS flip-flop is the output terminal of the oscillator, and the inverting output terminal is connected to the input terminal of the voltage-current converter through wires.

As a preferred technical solution of the present invention, the digital adjustment circuit is a controllable thyristor array, which includes a total of 6 turn-off thyristors, and the gates of the thyristors are connected to the current output terminals of the configurable registers.

As a preferred technical solution of the present invention, a temperature compensation MOS transistor is connected between the two input MOS transistors of the mirror circuit, and the gate of the temperature compensation MOS transistor is connected to the output terminal of the operational amplifier.

Compared with the prior art, the beneficial effect of the utility model is that: the new high-precision RC oscillator circuit fine-tunes the charging current to adjust the output frequency by setting a digital tuning circuit; influence; by setting the RS flip-flop, combined with the stacked structure of the double-limit comparator, the error caused by the hysteresis of the comparator to the oscillation frequency is eliminated; by reducing the sensitivity of the oscillator to voltage, temperature and process deviation, the oscillation is greatly improved The accuracy of the device, thus providing a stable and accurate clock signal.

Description of drawings

Fig. 1 is the schematic diagram of circuit structure of the utility model;

Figure 2 is a schematic diagram of the RC charging and discharging circuit;

Fig. 3 is a schematic diagram of mirror circuit;

Figure 4 is a schematic diagram of the digital tuning circuit.

In the figure: 1 - operational amplifier; 2 - configurable register; 3 - mirror circuit; 4 - standard voltage source; 5 - voltage current converter; 6 - double limit comparator circuit; 7 - first hysteresis comparator; 8 - The second hysteresis comparator; 9-RS flip-flop; 10-digital adjustment circuit; 11-RC charge and discharge circuit; 12-temperature compensation MOS tube; 13-reference voltage source.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. example. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

Example:

Please refer to Figures 1 to 4, the utility model provides a technical solution: a novel high-precision RC oscillator circuit, including an operational amplifier 1 and a configurable register 2, the non-inverting input of the operational amplifier 1 is connected to a reference voltage source 13, the output end of the operational amplifier 1 is connected with a mirror circuit 3, and the inverting input end is also connected to the near-ground end of the mirror circuit 3 through a wire, and the non-inverting input end of the mirror circuit 3 is connected with a standard voltage source 4, and the reverse The phase input end is connected with a voltage-current converter 5, and the output end of the voltage-current converter 5 is connected with a double-limit comparator circuit 6 and an RC charge-discharge circuit 11; the double-limit comparator circuit 6 includes a first hysteresis comparator 7 and The second hysteresis comparator 8, the inverting terminal of the first hysteresis comparator 7 and the non-inverting end of the second hysteresis comparator 8 are all connected to the reference voltage source 13, and the non-inverting input terminal of the first hysteresis comparator 7 is connected with an RC charger. Discharging circuit 11, the inverting input terminal of the second hysteresis comparator 8 is grounded, the output terminal of the double-limit comparator circuit 6 is connected with an RS flip-flop 9; the configurable register 2 is connected with a digital tuning circuit 10, digital tuning The circuit 10 is connected between the outputs of the mirror circuit 3 .

The S end of the RS flip-flop 9 is connected to the output end of the first hysteresis comparator 7, the R end is connected to the output end of the second hysteresis comparator 8, the non-inverting output end of the RS flip-flop 9 is the oscillator output end, and the reverse The phase output terminal is connected to the input terminal of the voltage-current converter 5 through wires; the digital trimming circuit 10 is a controllable thyristor array, including 6 turn-off thyristors, and the gate of the thyristor is connected to the configurable register 2 The current output terminal of the mirror circuit 3 is also connected with a temperature compensation MOS transistor 12 between the two input MOS transistors of the mirror circuit 3, and the gate of the temperature compensation MOS transistor 12 is connected to the output terminal of the operational amplifier 1.

The working principle of the utility model: the operational amplifier 1 constitutes an inverse proportional amplifier, which clamps the voltage at the output terminal to the same potential as the reference voltage source 13; the mirror circuit 3 forms a constant voltage source circuit, which provides stability for the RC charging and discharging circuit. Voltage; the standard voltage source 4 provides a turn-on voltage for the mirror circuit 3, and the voltage-to-current converter 5 converts the reference voltage source into a reference current source, and the converted current signal charges the RC charge-discharge circuit 11; the first Both the hysteresis comparator 7 and the second hysteresis comparator 8 have one section connected to the reference voltage source, and the other ends are respectively connected to the two poles of the capacitor of the RC charging and discharging circuit 11. When the voltage at both ends of the capacitor exceeds the reference voltage, the oscillator output voltage reverses , forming an oscillation waveform; the RS flip-flop 9 is connected to two hysteresis comparators and forms a symmetrical structure, eliminating the error caused by the comparator hysteresis to the oscillation frequency; the configurable register 2 outputs different high and low levels to the digital according to the built-in program The trimming circuit 10 can turn off the gate of the thyristor, control the switch of the thyristor, and fine-tune the charging current; the temperature compensation MOS transistor 12 increases the input impedance to compensate for the decrease in the resistance of the thyristor caused by the temperature rise. influence and improve circuit accuracy.

The new high-precision RC oscillator circuit, by setting the digital tuning circuit, fine-tunes the charging current to adjust the output frequency; by setting the temperature compensation MOS tube to eliminate the influence of temperature changes; by setting the RS flip-flop, combined with the dual-limit comparator The stacked structure eliminates the error caused by the hysteresis of the comparator to the oscillation frequency; by reducing the sensitivity of the oscillator to voltage, temperature and process deviation, the accuracy of the oscillator is greatly improved, thereby providing a stable and accurate clock signal.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present utility model shall be included in this utility model. within the scope of protection of utility models.

Claims (4)

1. a novel high-precision RC oscillator circuit, comprising an operational amplifier (1) and a configurable register (2), the non-inverting input of the operational amplifier (1) is connected with a reference voltage source (13), and the operational amplifier (1) ) is connected to a mirror image circuit (3), and the inverting input end is also connected to the near-ground end of the mirror image circuit (3) through a wire, and it is characterized in that: the non-inverting input end of the mirror image circuit (3) is connected with a standard A voltage source (4), the inverting input end is connected with a voltage-current converter (5), and the output end of the voltage-current converter (5) is connected with a double-limit comparator circuit (6) and an RC charge-discharge circuit (11); The dual-limit comparator circuit (6) comprises a first hysteresis comparator (7) and a second hysteresis comparator (8), an inverting terminal of the first hysteresis comparator (7) and the second hysteresis comparator (8) The non-inverting ends of both are connected to the reference voltage source (13), the non-inverting input end of the first hysteresis comparator (7) is connected with an RC charge-discharge circuit (11), and the inverting input end of the second hysteresis comparator (8) is grounded , the output end of the double-limit comparator circuit (6) is connected with an RS flip-flop (9); the configurable register (2) is connected with a digital tuning circuit (10), and the digital tuning circuit (10) is connected to the mirror circuit (3) between the output terminals. 2. a kind of novel high-precision RC oscillator circuit according to claim 1 is characterized in that: the S end of described RS flip-flop (9) is connected to the output end of the first hysteresis comparator (7), and the R end Connected to the output terminal of the second hysteresis comparator (8), the non-inverting output terminal of the RS flip-flop (9) is the oscillator output terminal, and the inverting output terminal is connected to the input terminal of the voltage-current converter (5) through wires. 3. A novel high-precision RC oscillator circuit according to claim 1, characterized in that: said digital tuning circuit (10) is a controllable thyristor array, including 6 turn-off thyristors, and the thyristors The gate of is connected to the current output of the configurable register (2). 4. a kind of novel high-precision RC oscillator circuit according to claim 1 is characterized in that: also be connected with temperature compensation MOS tube (12) between the input two MOS tubes of described mirror image circuit (3), and temperature The gate of the compensation MOS transistor (12) is connected to the output terminal of the operational amplifier (1).