A square wave generator with adjustable duty cycle
The square wave generator addresses the issue of fixed polarity and non-adjustable duty cycle by using comparators and transistors to create a single-polarity wave with adjustable duty cycle, enabling automatic adjustment based on input voltage and feedback.
Patent Information
- Application Number
- CN202110652593.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-06-11
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2041-06-11
AI Technical Summary
The duty cycle of the existing square wave generator circuit cannot be automatically adjusted according to the input voltage, resulting in it being unable to follow the feedback signal for automatic adjustment.
The circuit consisting of comparators U1A and U1B, capacitors C1-C4, voltage-regulating diodes D1-D4 and resistors R1-R8 is used to generate positive voltage unipolar square waves through the charging and discharging control of transistors Q1 and Q2 and capacitor C1, and automatically adjust the duty cycle by adjusting resistors R5, capacitor C1 and capacitor C2.
The positive voltage unipolarity of the square wave is realized, and the duty cycle can be automatically adjusted according to the input voltage, which is suitable for automatic adjustment of feedback signals in specific occasions.
Smart Images
Figure CN113328731B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of square wave generators, and particularly to a square wave generator with adjustable duty cycle. Background Art
[0002] At present, the square wave generated by the square wave generating circuit through the integrating circuit is bipolar with positive and negative voltages. The duty cycle of the existing square wave generating circuit cannot be automatically adjusted according to the input voltage, so that its duty cycle cannot be automatically adjusted following the feedback signal. Based on this problem, we propose a square wave generator with adjustable duty cycle. Summary of the Invention
[0003] The purpose of the present invention is to solve the deficiencies existing in the prior art, and to propose a square wave generator with adjustable duty cycle.
[0004] To achieve the above purpose, the present invention adopts the following technical solutions:
[0005] A square wave generator with adjustable duty cycle includes a comparator U1A and a comparator U1B. The pin 6 of the comparator U1B is electrically connected to the collector of a triode Q2, the pin 2 of the comparator U1A, one end of a capacitor C1, and the positive pole of a diode D3. The other end of the capacitor C1 is grounded. The emitter of the triode Q2 is electrically connected to one end of a resistor R3. The other end of the resistor R3 is electrically connected to the negative pole of a diode D4 and an input power supply V1+. The base of the triode Q2 is electrically connected to the positive pole of the diode D4 and one end of a resistor R4. The other end of the resistor R4 is grounded. The negative pole of the diode D3 is electrically connected to the negative pole of a diode D2, the collector of a triode Q1, the base of the triode Q1, the negative pole of a diode D1, and one end of a resistor R2. The other end of the resistor R2 is grounded. The emitter of the triode Q1 is electrically connected to one end of a resistor R1. The other end of the resistor R1 is electrically connected to the positive pole of the diode D1 and an input power supply V1-. The positive pole of the diode D2 is electrically connected to the pin 7 of the comparator U1B and one end of a resistor R6. The other end of the resistor R6 is electrically connected to the pin 5 of the comparator U1B, one end of a capacitor C2, one end of a resistor R5, and one end of a resistor R7. The other end of the resistor R5 is electrically connected to the other end of the capacitor C2 and is grounded. The other end of the resistor R7 is electrically connected to one end of a capacitor C3, the pin 3 of the comparator U1A, one end of a resistor R8, one end of a capacitor C4, and an input signal voltage Ui. The other end of the capacitor C3 is grounded. The other end of the resistor R8 is electrically connected to the other end of the capacitor C4, the pin 1 of the comparator U1A, and an output signal port Uo.
[0006] Preferably, the pin 4 of the comparator U1B is electrically connected to an input power supply V2+, and the pin 8 of the comparator U1B is grounded.
[0007] Preferably, the pin 4 of the comparator U1A is electrically connected to the input power supply V2+, and the pin 8 of the comparator U1A is grounded.
[0008] Preferably, both the diode D4 and the diode D1 are zener diodes.
[0009] The square wave generated by the present invention is positive voltage unipolar, and the duty cycle can be automatically adjusted following the input voltage, and further the duty cycle can be automatically adjusted following the feedback signal in specific occasions. Description of the Drawings
[0010] Figure 1 It is the internal circuit diagram of a square wave generator with adjustable duty cycle proposed by the present invention. Detailed Embodiment
[0011] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.
[0012] Refer to Figure 1, a duty cycle adjustable square wave generator, including comparator U1A and comparator U1B. The pin 4 of comparator U1B is electrically connected to input power supply V2+, and the pin 8 of comparator U1B is grounded. The pin 6 of comparator U1B is electrically connected to the collector of triode Q2, the pin 2 of comparator U1A, one end of capacitor C1 and the positive electrode of diode D3. The other end of capacitor C1 is grounded. The emitter of triode Q2 is electrically connected to one end of resistor R3. The other end of resistor R3 is electrically connected to the negative electrode of diode D4 and input power supply V1+. The base of triode Q2 is electrically connected to the positive electrode of diode D4 and one end of resistor R4. The other end of resistor R4 is grounded. The negative electrode of diode D3 is electrically connected to the negative electrode of diode D2, the collector of triode Q1, the base of triode Q1, the negative electrode of diode D1 and one end of resistor R2. The other end of resistor R2 is grounded. The emitter of triode Q1 is electrically connected to one end of resistor R1. The other end of resistor R1 is electrically connected to the positive electrode of diode D1 and input power supply V1-. Diodes D4 and D1 are both zener diodes. The positive electrode of diode D2 is electrically connected to the pin 7 of comparator U1B and one end of resistor R6. The other end of resistor R6 is electrically connected to the pin 5 of comparator U1B, one end of capacitor C2, one end of resistor R5 and one end of resistor R7. The other end of resistor R5 is electrically connected to the other end of capacitor C2 and grounded. The other end of resistor R7 is electrically connected to one end of capacitor C3, the pin 3 of comparator U1A, one end of resistor R8, one end of capacitor C4 and input signal voltage Ui. The pin 4 of comparator U1A is electrically connected to input power supply V2+. The pin 8 of comparator U1A is grounded. The other end of capacitor C3 is grounded. The other end of resistor R8 is electrically connected to the other end of capacitor C4, the pin 1 of comparator U1A and output signal port Uo. The square wave generated by the present invention is positive voltage unipolar, and the duty cycle can be automatically adjusted following the input voltage, and further, in specific occasions where the duty cycle needs to be automatically adjusted following the feedback signal.
[0013] In the present invention, the input power supply V1+ charges the capacitor C1 through the constant current circuit composed of the triode Q2, the diode D4, the resistor R3 and the resistor R4. The voltage of the capacitor C1 keeps rising, and the voltage at the output end of the comparator U1B also rises accordingly. However, during this process, the voltage at the output end of the comparator U1B is always higher than the voltage of the capacitor C1, resulting in the cut-off of the diode D3. Therefore, the constant current circuit composed of the triode Q1, the diode D1, the resistor R1 and the resistor R2 cannot discharge the capacitor C1. When the input power supply V1+ is greater than the input power supply V2+, the output voltage of the comparator U1B reaches the maximum input power supply V2+, and the voltage of the capacitor C1 keeps rising and exceeds the input power supply V2+. Then the diode D3 conducts, and the constant current circuit composed of the triode Q1, the diode D1, the resistor R1 and the resistor R2 starts to discharge the capacitor C1. When the voltage is discharged to 0V, the comparator U1B flips again and enters the next cycle, thus forming a triangular wave.
[0014] For the charge and discharge circuit built by the diode and the voltage regulator diode, the voltage drop VD4 of the diode D4 and the BE voltage VQ2_be of the triode Q2 are constant, resulting in the constant voltage of the resistor R3. Therefore, the charge and discharge slope of the capacitor can be controlled.
[0015] The triangular wave is compared with the input signal voltage Ui through the comparator U1A to generate a unipolar square wave with adjustable duty cycle.
[0016] The frequency is adjusted by adjusting the resistors R5, R6, capacitors C1 and C2, and the duty cycle is adjusted by adjusting the input signal voltage Ui.
[0017] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "install", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be a direct connection or a connection through an intermediate medium. It can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.
[0018] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.
Claims
1. A duty cycle adjustable square wave generator, comprising a comparator U1A and a comparator U1B, characterized in that, The collector of transistor Q2, pin 2 of comparator U1A, one end of capacitor C1, and the positive electrode of diode D3 are electrically connected to pin 6 of comparator U1B. The other end of capacitor C1 is grounded. One end of resistor R3 is electrically connected to the emitter of transistor Q2. The other end of resistor R3 is electrically connected to the negative electrode of diode D4 and input power supply V1+. The base of transistor Q2 is electrically connected to the positive electrode of diode D4 and one end of resistor R4. The other end of resistor R4 is grounded. The negative electrode of diode D3 is electrically connected to the negative electrode of diode D2, the collector of transistor Q1, the base of transistor Q1, the negative electrode of diode D1, and one end of resistor R2. The other end of resistor R2 is grounded. One end of resistor R1 is electrically connected to the emitter of transistor Q1. The other end of resistor R1 is electrically connected to the positive electrode of diode D1 and input power supply V1-. The positive electrode of diode D2 is electrically connected to pin 7 of comparator U1B and one end of resistor R6. The other end of resistor R6 is electrically connected to pin 5 of comparator U1B, one end of capacitor C2, one end of resistor R5, and one end of resistor R7. The other end of resistor R5 is electrically connected to the other end of capacitor C2 and is grounded. The other end of resistor R7 is electrically connected to one end of capacitor C3, pin 3 of comparator U1A, one end of resistor R8, one end of capacitor C4, and input signal voltage Ui. The other end of capacitor C3 is grounded. The other end of resistor R8 is electrically connected to the other end of capacitor C4, pin 1 of comparator U1A, and output signal port Uo.
2. The square wave generator with adjustable duty cycle according to claim 1, characterized in that Pin 4 of comparator U1B is electrically connected to input power supply V2+, and pin 8 of comparator U1B is grounded.
3. A duty cycle adjustable square wave generator according to claim 1, wherein Pin 4 of comparator U1A is electrically connected to input power supply V2+, and pin 8 of comparator U1A is grounded.
4. A duty cycle adjustable square wave generator according to claim 1, wherein Both diode D4 and diode D1 are zener diodes.
Citation Information
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