Relaxation oscillator

Abstract

The utility model relates to a relaxation oscillator. Comprising a resistor, a capacitor, a voltage comparator, a low-pass filter and a temperature compensation circuit, the resistor and the capacitor are combined to form an RC charging circuit which is responsible for generating a gradually changing voltage. The voltage can generate charging and discharging fluctuations at the two ends of the capacitor as time goes on, and then periodic changes are provided for the oscillator. And the voltage comparator is used for monitoring the voltage on the capacitor. And two input ends of the comparator are respectively connected to a connection point of the capacitor and a reference voltage Vref. When the voltage at the two ends of the capacitor exceeds or is lower than the reference voltage Vref, the comparator outputs a digital signal (high or low) so as to trigger the oscillation behavior. And the output signal enters the low-pass filter after passing through the voltage comparator. The low-pass filter is used for smoothing signals, reducing high-frequency noise and stabilizing signal output.

Description

Technical Field

[0001] This utility model relates to the field of relaxation oscillator technology, specifically a relaxation oscillator. Background Technology

[0002] A relaxation oscillator is a nonlinear circuit commonly used to study chaotic dynamics systems. Relaxation oscillators have wide applications in various fields: they are used to study and demonstrate the principles of chaotic phenomena. In some communication systems, relaxation oscillators are used to generate specific modulation signals. In some nonlinear control theories, relaxation oscillators serve as examples for studying nonlinear dynamic systems. In general, as a typical nonlinear system, the relaxation oscillator can help us understand the fundamental concepts of chaos theory and nonlinear dynamics.

[0003] In existing relaxation oscillator designs, the frequency is often affected by factors such as external temperature changes, component aging, and power supply noise. Especially when using simple RC circuits or oscillators constructed from transistors, the frequency stability is poor, making it difficult to meet the requirements of high-precision applications.

[0004] Meanwhile, the design of traditional relaxation oscillators may require multiple components (such as multiple RC networks, amplifiers, etc.) to achieve stable high-frequency oscillation. This makes the circuit design complex, difficult to integrate, and increases manufacturing costs. Therefore, in order to meet the above requirements, a relaxation oscillator is needed. Utility Model Content

[0005] Purpose of the utility model: To provide a relaxation oscillator to solve the problems mentioned above.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A relaxation oscillator includes: a resistor, a capacitor, a voltage comparator, a low-pass filter, and a temperature compensation circuit; the resistor and capacitor form an RC charging circuit; one of the input terminals of the voltage comparator is connected to the connection point of the capacitor, and the other terminal is connected to a reference voltage Vref; the output signal is fed back to a voltage averaging circuit, and the low-pass filter achieves voltage smoothing; finally, a feedback loop is used to feed the output frequency back to an adjustment circuit.

[0008] By incorporating a low-pass filter, temperature compensation circuit, and feedback loop, the circuit's stability is improved, and it can maintain a stable oscillation frequency under different environmental conditions. Further improvements to the temperature compensation and filter design, along with the addition of digital adjustment and integrated design, will further enhance the circuit's performance and reliability in practical applications.

[0009] According to one aspect of the present application, one end of the capacitor is connected to the output terminal of the voltage comparator, and the other end of the capacitor is connected to the power supply through the resistor; the output terminal of the voltage comparator is connected to the output terminal of the charging circuit.

[0010] According to one aspect of the embodiments of this application, the resistor and capacitor are combined to form a low-pass filter to smooth the output signal, and the feedback signal is connected from the output terminal of the voltage comparator to the capacitor through the resistor, and the other end of the capacitor is grounded.

[0011] The output of the voltage comparator is connected to a capacitor via a resistor, with the other end of the capacitor grounded, forming a typical low-pass filter. This circuit smooths the output signal and adjusts its frequency and shape via a feedback loop. The combination of capacitor and resistor determines the characteristics of the low-pass filter, while the feedback loop provides dynamic adjustment capabilities.

[0012] According to one aspect of the embodiments of this application, the temperature compensation element in the temperature compensation circuit includes: a thermistor (NTC or PTC) and a temperature compensation diode.

[0013] These temperature compensation components work together to ensure that the circuit can operate stably under different temperature conditions, reducing the impact of temperature changes on circuit performance.

[0014] According to one aspect of the embodiments of this application, the temperature compensation circuit is connected to the resistor R terminal in the RC charging circuit, and the forward voltage of the diode changes with temperature to adjust the value of Vref.

[0015] According to one aspect of the embodiments of this application, the output frequency is compared with a predetermined frequency using a feedback loop to correct the operating frequency of the oscillator in real time.

[0016] By comparing the output frequency with the predetermined frequency through a feedback loop, the operating frequency of the oscillator can be corrected in real time, ensuring its stability under changes in temperature, load, and other environmental conditions.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] By employing temperature compensation technology and digital feedback, the frequency stability of the oscillator can be significantly improved. This can be achieved through dynamic adjustments using a temperature sensor or by using high-precision digital signal processing to compensate for frequency drift.

[0019] Using integrated digital control modules to replace traditional analog circuits reduces the number of components, lowers system complexity, and enhances system integrability and maintainability. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the principle of a relaxation oscillator according to the present invention. Detailed Implementation

[0021] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid confusion with the present invention.

[0022] This utility model relates to a relaxation oscillator, which, in practical applications, such as... Figure 1 As shown, the circuit includes: resistors, capacitors, a voltage comparator, a low-pass filter, and a temperature compensation circuit. The resistors and capacitors combine to form an RC charging circuit, responsible for generating a gradually changing voltage. This voltage fluctuates across the capacitor as it charges and discharges over time, providing periodic variations for the oscillator. The voltage comparator monitors the voltage across the capacitor. Its two inputs are connected to the capacitor's connection point and a reference voltage Vref, respectively. When the voltage across the capacitor exceeds or falls below the reference voltage Vref, the comparator outputs a digital signal (high or low), triggering oscillation. The output signal passes through the voltage comparator and then enters the low-pass filter. The low-pass filter smooths the signal, reduces high-frequency noise, and stabilizes the signal output. It helps eliminate unwanted high-frequency fluctuations in the circuit and converts the output signal into a smoother, more controllable voltage signal. The voltage averaging circuit is an integrator or buffer circuit that receives the smoothed signal from the low-pass filter and outputs a stable control voltage. This voltage signal is used to further regulate the circuit's operating state. Since temperature variations can affect the performance of the resistors, capacitors, and voltage comparator, the temperature compensation circuit is used to reduce the impact of temperature on circuit performance. Temperature compensation circuits typically utilize thermistors (NTC / PTC) or temperature sensors for feedback, automatically adjusting circuit parameters (such as resistance or capacitance values) to ensure the oscillator maintains a stable output frequency under varying temperature conditions. Ultimately, the oscillator's output frequency is fed back to the regulation circuit via a feedback loop, adjusting its parameters (such as resistance, capacitance, or voltage) to achieve frequency stability and precise control. The feedback loop design ensures the circuit's self-adaptive capability, allowing it to adjust the output frequency according to actual conditions.

[0023] In practical use, the capacitor charges through the resistor. When the voltage across the capacitor reaches the reference voltage Vref, the voltage comparator triggers an output signal, causing the capacitor to discharge and forming a periodic waveform. The voltage comparator monitors the capacitor voltage in real time and generates a pulse signal. A low-pass filter smooths the pulse signal, resulting in a more stable output voltage signal. The voltage averaging circuit processes the signal, maintaining frequency stability and adapting it to different operating environments. The temperature compensation circuit automatically adjusts circuit parameters according to temperature changes, ensuring that the circuit's output frequency is unaffected by temperature. The feedback loop adjusts the RC value in the circuit based on the output frequency, ensuring precise control of the system's oscillation frequency.

[0024] In the above embodiment, the voltage comparator is further used to compare the input signal with a reference voltage. The output of the voltage comparator can provide a high or low level, typically a digital signal (e.g., high level represents "1", low level represents "0"). When one end of a capacitor is connected to the output of the voltage comparator, the capacitor charges or discharges according to the output level of the voltage comparator. The other end of the capacitor is connected to the power supply through a resistor, and the capacitor charges or discharges through the resistor. The specific charging and discharging rates depend on the values ​​of the resistor and capacitor (RC time constant). When the voltage comparator output changes, the capacitor changes its voltage, thus affecting other parts of the circuit. The output of the charging circuit is related to the change in capacitor voltage. The output of the voltage comparator may control the operating state of the charging circuit, and conversely, the change in capacitor voltage may affect the output of the voltage comparator.

[0025] In the above embodiment, the resistor and capacitor are further combined to form a low-pass filter. The low-pass filter filters out high-frequency noise in the signal through the smoothing effect of the capacitor, allowing only low-frequency signals to pass, thereby smoothing the output signal. The feedback signal is connected from the output of the voltage comparator to one end of the capacitor through a resistor. The other end of the capacitor is grounded. The output signal enters the capacitor through the resistor, where the capacitor integrates (or smooths) the signal and feeds it back into the circuit. The charging and discharging process of the capacitor can affect the shape and amplitude of the feedback signal, thus affecting the oscillation characteristics of the circuit.

[0026] In the above embodiments, the thermistor further varies with temperature. Thermistors are classified into two types: NTC (Negative Temperature Coefficient Thermistor): In NTC thermistors, the resistance decreases as temperature increases. They are typically used in temperature compensation circuits to help reduce instability caused by temperature changes in the circuit. PTC (Positive Temperature Coefficient Thermistor): In PTC thermistors, the resistance increases as temperature increases. They are mainly used in circuits for overload protection, current limiting, and as temperature-sensitive switches.

[0027] Temperature-compensating diodes are composed of multiple diodes or diodes with a special structure. The forward voltage of a diode exhibits a stable variation characteristic with temperature changes; however, the forward voltage decreases by approximately 2mV for every 1°C increase in temperature. They are used to compensate for temperature changes in circuits.

[0028] In the above embodiment, the resistor is further connected to the resistor terminal in the RC charging circuit, forming a temperature-compensated feedback network together with the diode and capacitor. The value of the resistor determines the charging rate of the capacitor, thus affecting the response characteristics of the entire circuit. The function of the temperature-compensating diode is to adjust the voltage when the temperature changes, thereby adjusting the behavior of the RC circuit through feedback. In this way, the operating characteristics of the RC circuit can remain consistent at different temperatures. The main objective of the temperature compensation circuit is to adjust the value of Vref through the diode. Since the forward voltage of the diode changes with temperature, this change can be used to compensate for the effect of temperature on the parameters of other components in the circuit (such as resistors, capacitors, operational amplifiers, etc.). In this configuration, the combination of the diode and the RC circuit can automatically adjust Vref, thereby maintaining the stability of the circuit. As the temperature rises or falls, the change in the forward voltage of the diode leads to the adjustment of Vref, enabling the circuit to adapt to different temperature conditions.

[0029] When the temperature changes, the forward voltage of the diode changes, and this change affects the value of the reference voltage Vref. When the temperature rises, the forward voltage of the diode decreases, causing Vref to adjust to compensate for the temperature-induced change.

[0030] In the above embodiments, a feedback loop is further used to compare the output frequency with a predetermined frequency to correct the operating frequency of the oscillator in real time.

[0031] A feedback loop utilizes a closed-loop system to monitor and adjust the output signal in real time to ensure it remains synchronized with a reference signal (a predetermined frequency). The specific process is as follows: The output frequency comes from an oscillator, and the oscillator's output signal is compared with a reference signal. This reference signal can be from an external standard source. By comparing the difference between the output frequency and the reference frequency, a control signal is obtained. This control signal is generated using a phase comparator or a frequency comparator. The phase comparator compares the phase difference between the output signal and the reference signal, generating an error signal proportional to the frequency difference. After filtering, the error signal is passed to the oscillator, and by adjusting its control input (control voltage), the oscillator frequency is corrected.

[0032] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A relaxation oscillator characterized by, Comprise: resistor, capacitor, voltage comparator, low pass filter and temperature compensation circuit; The resistor and capacitor form an RC charging circuit; One of the input terminals of the voltage comparator is connected to the connection point of the capacitor, and the other terminal is connected to the reference voltage Vref; The output signal is fed back to the voltage averaging circuit, and the low pass filter realizes voltage smoothing; Finally, the output frequency is fed back to the adjustment circuit using a feedback loop.

2. A relaxation oscillator as claimed in claim 1, characterized in that: One end of the capacitor is connected to the output terminal of the voltage comparator, and the other end of the capacitor is connected to the power supply through the resistor; the output terminal of the voltage comparator is connected to the output terminal of the charging circuit.

3. A relaxation oscillator as claimed in claim 1, characterized in that: The resistor and capacitor combination forms a low pass filter to smooth the output signal; the feedback signal is connected from the output terminal of the voltage comparator to the capacitor through the resistor, and the other end of the capacitor is grounded.

4. A relaxation oscillator as claimed in claim 1, characterized in that: The temperature compensation element in the temperature compensation circuit includes: thermistor (NTC or PTC) and temperature compensation diode.

5. A relaxation oscillator as claimed in claim 1, characterized in that: The temperature compensation circuit is resistively connected to the resistor R in the RC charging circuit, and the forward voltage of the diode changes with temperature, which is used to adjust the value of Vref.

6. A relaxation oscillator as claimed in claim 1, characterized in that: The output frequency is compared with the predetermined frequency using a feedback loop, and the working frequency of the oscillator is corrected in real time.

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