A circuit structure for dynamically adjusting the duty cycle of an input signal
By designing the circuit structure of a rail-to-rail comparator and a square wave adjustment circuit, the synchronization anomaly caused by the inconsistency between the duty cycle of the purchased power adapter and the mains power frequency signal was solved, achieving a fast and stable signal adjustment effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZTE INTELLIGENT IOT TECH
- Filing Date
- 2025-06-09
- Publication Date
- 2026-06-09
AI Technical Summary
In existing technologies, the duty cycle of the purchased power adapter is inconsistent with the duty cycle of the mains power frequency signal, which leads to the problem of abnormal synchronization of the video RF integrated machine.
Design a circuit structure including a rail-to-rail comparator, a low-pass filter, and a square wave adjustment circuit. The rail-to-rail comparator is used for signal comparison and square wave adjustment to achieve dynamic real-time adjustment of the duty cycle of the input signal.
It achieves fast-response signal adjustment, reduces synchronization anomalies, ensures stable and reliable output results, and has a simple circuit structure and low cost, making it suitable for duty cycle adjustment of low-frequency square wave signals.
Smart Images
Figure CN224343166U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of circuit structure technology, specifically to a circuit structure for dynamically and in real-time adjusting the duty cycle of an input signal. Background Technology
[0002] In video RF integrated cameras, an externally purchased power adapter is required to provide power and a power frequency synchronization signal so as to synchronize with the external flash light and prevent overexposure when capturing images.
[0003] However, in practical applications, due to the design of the purchased adapter or the influence of the usage environment, the duty cycle of the adapter may not be completely consistent with the duty cycle of the mains power frequency signal, which will lead to synchronization abnormalities. Therefore, it is urgent to design a circuit structure for dynamically adjusting the duty cycle of the input signal in real time to solve the above problems. Utility Model Content
[0004] The purpose of this invention is to provide a circuit structure for dynamically and in real-time adjusting the duty cycle of an input signal, thereby addressing the aforementioned shortcomings in the prior art.
[0005] To achieve the above objectives, this utility model provides the following technical solution:
[0006] A circuit structure for dynamically adjusting the duty cycle of an input signal in real time, comprising:
[0007] A rail-to-rail comparator, comprising two input terminals and one output terminal, wherein the two input terminals are positive and negative, respectively;
[0008] A low-pass filter is used to receive a square wave signal, perform high-frequency removal and adjustment to obtain a sawtooth wave signal, and the output terminal of the low-pass filter is connected to the positive input terminal.
[0009] A square wave adjustment circuit is provided, wherein the input terminal of the square wave adjustment circuit is connected to the output terminal of the rail-to-rail comparator, and the output terminal of the square wave adjustment circuit is connected to the negative input terminal of the rail-to-rail comparator. The square wave adjustment circuit is used to acquire square wave signals and reverse shape them to obtain a reference level signal for dynamic adjustment.
[0010] The positive input terminal of the rail-to-rail comparator receives a sawtooth wave signal, and the negative input terminal of the rail-to-rail comparator receives a dynamically adjusted reference level signal. The two signals are compared and used to determine the square wave signal that meets the expected duty cycle.
[0011] Preferably, the rail-to-rail comparator compares the reference level signal, and the portion higher than the reference voltage is determined as a positive value, and the portion lower than the reference voltage is determined as a negative value, thus obtaining a square wave signal with the same frequency as the input signal.
[0012] Preferably, the square wave adjustment circuit includes a transistor VT1, the collector of the transistor VT1 is connected to the VDD power supply voltage through a resistor R1, and the emitter of the transistor VT1 is connected to the ground plane D.
[0013] Preferably, the base of the transistor VT1 is connected to the square wave signal input terminal through resistor R3, and the collector of the transistor VT1 is connected to the reference level signal output terminal through resistor R2.
[0014] Preferably, the base of the transistor VT1 is connected to ground plane D through resistor R4, and the reference level signal output terminal is connected to ground plane D through capacitor C1.
[0015] In the above technical solution, the circuit structure provided by this utility model for dynamically and in real-time adjusting the duty cycle of the input signal has the following advantages:
[0016] By setting up a square wave adjustment circuit, feedback can be established between the square wave adjustment circuit and the rail-to-rail comparator, enabling rapid response, achieving the purpose of signal adjustment, reducing synchronization anomalies, ensuring stable and reliable output results, and having a very low implementation cost. It requires no complex software adjustments, has a simple circuit structure, is easy to adjust, and is highly adaptable. It is particularly suitable for adjusting the duty cycle of low-frequency square wave signals. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings.
[0018] Figure 1 This is a basic block diagram of a circuit provided for an embodiment of the circuit structure of this utility model for dynamically and in real-time adjusting the duty cycle of an input signal.
[0019] Figure 2 This is a schematic diagram of a square wave adjustment circuit provided for an embodiment of the circuit structure of this utility model for dynamically and in real-time adjusting the duty cycle of an input signal. Detailed Implementation
[0020] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings.
[0021] like Figure 1-2 As shown in the figure, an embodiment of the present invention provides a circuit structure for dynamically and in real-time adjusting the duty cycle of an input signal, comprising:
[0022] A rail-to-rail comparator includes two input terminals and one output terminal, with the two input terminals being the positive and negative terminals, respectively.
[0023] A low-pass filter is used to receive a square wave signal, perform high-frequency removal and adjustment to obtain a sawtooth wave signal, and the output terminal of the low-pass filter is connected to the positive input terminal.
[0024] The square wave adjustment circuit has its input terminal connected to the output terminal of the rail-to-rail comparator, and its output terminal connected to the negative input terminal of the rail-to-rail comparator. The square wave adjustment circuit is used to acquire square wave signals and reverse shape them to obtain a reference level signal for dynamic adjustment.
[0025] The positive input of the rail-to-rail comparator receives a sawtooth wave signal, and the negative input of the rail-to-rail comparator receives a dynamically adjusted reference level signal. The two signals are compared and used to determine the square wave signal that meets the expected duty cycle.
[0026] Preferably, the rail-to-rail comparator compares the reference level signal, and the part higher than the reference voltage is determined as a positive value, and the part lower than the reference voltage is determined as a negative value, thus obtaining a square wave signal with the same frequency as the input signal.
[0027] The rail-to-rail comparator compares the reference level signal voltage value based on the dynamic adjustment. The duty cycle of the square wave signal is adjusted according to the level of the reference level signal voltage value output by the square wave adjustment circuit.
[0028] Preferably, the square wave adjustment circuit includes a transistor VT1, the collector of transistor VT1 is connected to the VDD power supply voltage through a resistor R1, and the emitter of transistor VT1 is connected to the ground plane D.
[0029] Preferably, the base of transistor VT1 is connected to the square wave signal input terminal through resistor R3, and the collector of transistor VT1 is connected to the reference level signal output terminal through resistor R2.
[0030] Preferably, the base of the transistor VT1 is connected to ground plane D through resistor R4, and the reference level signal output terminal is connected to ground plane D through capacitor C1.
[0031] In this circuit, the base of transistor VT1 receives a square wave signal, which is then shaped and amplified by transistor VT1. The amplified signal is then filtered and shaped by resistor R2 and capacitor C1 before being output, thus achieving the purpose of signal adjustment.
[0032] Working principle: The low-pass filter receives the square wave signal and filters and adjusts it, removing high-frequency components and outputting a sawtooth wave signal. This sawtooth wave signal is fed into the positive input of the rail-to-rail comparator, which outputs a square wave signal. The square wave adjustment circuit collects the square wave signal output from the rail-to-rail comparator, shapes and amplifies it using transistor VT1, and then filters it through resistor R2 and capacitor C1, outputting a relatively flat level signal. This signal is then input into the negative input of the rail-to-rail comparator. The rail-to-rail comparator compares the signal with a reference voltage value, identifying values higher than the reference voltage as positive and lower as negative, thus producing a square wave signal with the same frequency as the input signal and achieving the desired duty cycle.
[0033] The foregoing description only illustrates certain exemplary embodiments of the present invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.
Claims
1. A circuit structure for dynamically and in real-time adjusting the duty cycle of an input signal, characterized in that, include: A rail-to-rail comparator, comprising two input terminals and one output terminal, wherein the two input terminals are positive and negative, respectively; A low-pass filter is used to receive a square wave signal, perform high-frequency removal and adjustment to obtain a sawtooth wave signal, and the output terminal of the low-pass filter is connected to the positive input terminal. A square wave adjustment circuit is provided, wherein the input terminal of the square wave adjustment circuit is connected to the output terminal of the rail-to-rail comparator, and the output terminal of the square wave adjustment circuit is connected to the negative input terminal of the rail-to-rail comparator. The square wave adjustment circuit is used to acquire square wave signals and reverse shape them to obtain a reference level signal for dynamic adjustment. The positive input terminal of the rail-to-rail comparator receives a sawtooth wave signal, and the negative input terminal of the rail-to-rail comparator receives a dynamically adjusted reference level signal. The two signals are compared and used to determine the square wave signal that meets the expected duty cycle.
2. The circuit structure for dynamically and in real-time adjusting the duty cycle of an input signal according to claim 1, characterized in that, The rail-to-rail comparator compares the signals based on a reference level signal. The portion higher than the reference voltage is determined to be a positive value, and the portion lower than the reference voltage is determined to be a negative value, thus obtaining a square wave signal with the same frequency as the input signal.
3. The circuit structure for dynamically and in real-time adjusting the duty cycle of an input signal according to claim 1, characterized in that, The square wave adjustment circuit includes a transistor VT1. The collector of the transistor VT1 is connected to the VDD power supply voltage through a resistor R1, and the emitter of the transistor VT1 is connected to the ground plane D.
4. The circuit structure for dynamically and in real-time adjusting the duty cycle of an input signal according to claim 3, characterized in that, The base of transistor VT1 is connected to the square wave signal input terminal through resistor R3, and the collector of transistor VT1 is connected to the reference level signal output terminal through resistor R2.
5. The circuit structure for dynamically and in real-time adjusting the duty cycle of an input signal according to claim 4, characterized in that, The base of the transistor VT1 is connected to ground plane D through resistor R4, and the reference level signal output terminal is connected to ground plane D through capacitor C1.