Constant current source square wave power supply circuit with adjustable duty ratio and frequency

Abstract

The invention discloses a constant current source square wave power supply circuit with adjustable duty ratio and frequency, and belongs to the technical field of circuit power supply control. Specifically, a power supply input unit is used as an input source of power supply of a power supply, a high level control unit and a low level control unit respectively control generation of high and low levels and setting of duty ratio and frequency, and square wave signals are output through a square wave output unit after the high and low levels are generated. A square wave signal reaches the constant current source generating unit and then generates a constant current source square wave signal, the current size adjusting unit is responsible for adjusting the size of the current of the constant current source, and finally, a constant current source square wave power supply signal which is set by the previous units and is adjustable in duty ratio and frequency is output to a rear-end load through the constant current source square wave output unit. According to the constant current source square wave power supply circuit, common electronic components are designed and used for building the circuit, and the constant current source square wave power supply circuit which is complex in function and adjustable in duty ratio and frequency is achieved.

Description

Technical Field

[0001] The invention relates to a constant current source square wave power supply circuit with adjustable duty cycle and frequency, belonging to the technical field of circuit power supply control. Background Art

[0002] Constant current source square wave circuits are widely used in electronic devices. They can provide stable current output, improve circuit performance, and play an important role in many fields.

[0003] In the voltage-stabilized power supply chip, the use of a constant current source square wave circuit can reduce the ripple voltage. In addition, the constant current source square wave circuit can provide a stable current output, which is very important for applications that require a constant current. For example, in an LED driver, the constant current source circuit can ensure the stability and accuracy of the current output.

[0004] In the medical endoscope camera system, the constant current source square wave circuit can be used to drive the light source LED and the laser LD. In the internal circuit of the operational amplifier, the constant current source square wave circuit can improve the disadvantage of low input impedance of the common base amplifier circuit and the high-speed operational amplifier, and the frequency characteristics can become quite good.

[0005] In circuit design, the duty cycle and frequency of the constant current source square wave circuit will be adjusted according to different circuit application requirements. For example, by adjusting the duty cycle, the output power can be effectively controlled. By adjusting the duty cycle and frequency, the signal can be precisely controlled to improve the stability and response speed of the system. At present, most designs use chips with programming functions to implement constant current source circuits and adjust their duty cycle and frequency. This method is not only costly but also usually consumes a lot of power. Summary of the invention

[0006] The purpose of the present invention is to provide a constant current source square wave power supply circuit with adjustable duty cycle and frequency, which can be widely used in circuit design, and provides a better design scheme for power supply power control, load adaptability, efficiency optimization, stability improvement, signal modulation and demodulation, power supply management and precise control, and has obvious cost advantages compared with other schemes.

[0007] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0008] A constant current source square wave power supply circuit with adjustable duty cycle and frequency, comprising a power input unit (1), a high level control unit (2), a low level control unit (3), a square wave output unit (4), a constant current source generating unit (5), a current magnitude adjusting unit (6), and a constant current source square wave output unit (7), wherein the power input unit (1) is connected to the high level control unit (2) and the square wave output unit (4), the high level control unit (2) is connected to the power input unit (1), the low level control unit (3), and the square wave output unit (4), and the low level control unit (3) is connected to the high level control unit (5). The square wave output unit (4) is connected to the constant current source generating unit (5); the square wave output unit (4) is connected to the power input unit (1), the high level control unit (2), the low level control unit (3) and the constant current source generating unit (5); the constant current source generating unit (5) is connected to the low level control unit (3), the square wave output unit (4), the current magnitude adjusting unit (6) and the constant current source square wave output unit (7); the current magnitude adjusting unit (6) is connected to the constant current source generating unit (5); the constant current source square wave output unit (7) is connected to the constant current source generating unit (5);

[0009] The power input unit (1) is a power supply input source module, which is used to receive power transmitted from the front end and provide power supply to the rear end high-level control unit (2) and the square wave output unit (4).

[0010] The current magnitude adjustment unit (6) is a module for adjusting the magnitude of the output current. The current magnitude adjustment unit (6) sets the magnitude of the current generated by the constant current source generating unit (5). The constant current source square wave output unit (7) is an output interface of the constant current source square wave power supply circuit. The constant current source square wave output unit (7) outputs the constant current source square wave signal generated by the constant current source generating unit to the outside.

[0011] Furthermore, the high-level control unit (2) comprises a first current regulating module (21), a first charge storage module (22), a second current limiting module (23), and a second N-type control module (24), wherein the first current regulating module (21) is connected to the first charge storage module (22) and the second current limiting module (23), the first charge storage module (22) is connected to the first current regulating module (21) and the second current limiting module (23), the second current limiting module (23) is connected to the first current regulating module (21), the first charge storage module (22), and the second N-type control module (24), and the second N-type control module (24) is connected to the second current limiting module (23).

[0012] Furthermore, the low-level control unit (3) comprises a fifth current regulating module (31), a second charge storage module (32), a fourth current limiting module (33), and a third N-type control module (34), wherein the fifth current regulating module (31) is connected to the second charge storage module (32) and the fourth current limiting module (33), the second charge storage module (32) is connected to the fifth current regulating module (31) and the fourth current limiting module (33), the fourth current limiting module (33) is connected to the fifth current regulating module (31), the second charge storage module (32), and the third N-type control module (34), and the third N-type control module (34) is connected to the fourth current limiting module (33).

[0013] Furthermore, the square wave output unit (4) comprises a first P-type control module (41) and a third current limiting module (42), wherein the first P-type control module (41) is connected to the third current limiting module (42).

[0014] Furthermore, the constant current source generating unit (5) comprises a fourth P-type control module (51) and a fifth P-type control module (52), wherein the fourth P-type control module (51) is connected to the fifth P-type control module (52).

[0015] Furthermore, the high-level control unit (2) controls the high-level portion of the square wave signal, and adjusts the magnitude of the charging current of the first charge storage module (22) through the first current regulating module (21). The magnitude of the charging current affects the time when the first charge storage module (22) is fully charged. The second current limiting module (23) limits the current flowing through the second N-type control module (24) to protect the second N-type control module (24). The second N-type control module (24) performs on-off control according to the set parameters.

[0016] Furthermore, the low-level control unit (3) controls the low-level part of the square wave signal, and adjusts the magnitude of the charging current of the second charge storage module (32) through the fifth current regulating module (31). The magnitude of the charging current affects the time when the second charge storage module (32) is charged. The fourth current limiting module (33) limits the current flowing through the third N-type control module (34) to protect the third N-type control module (34). The third N-type control module (34) performs on-off control according to the set parameters.

[0017] Furthermore, the square wave output unit (4) is a unit that outputs a square wave signal, the first P-type control module (41) controls the on and off of the square wave signal output, and the third current limiting module (42) limits the current flowing through the first P-type control module (41) to protect the first P-type control module (41).

[0018] Furthermore, the constant current source generating unit (5) performs constant current conversion on the current in the circuit, the fourth P-type control module (51) generates a reference current output by the constant current source, and the fifth P-type control module (52) generates the same current with reference to the reference current set by the fourth P-type control module (51) and provides it to subsequent loads for use.

[0019] Furthermore, the frequency and duty cycle of the constant current source square wave signal can be adjusted by simply setting the parameters of the high level control unit (2) and the low level control unit (3).

[0020] The beneficial effects of the present invention are as follows: a constant current source square wave power supply circuit with adjustable duty cycle and frequency provided by the present invention comprises: a power input unit, a high level control unit, a low level control unit, a square wave output unit, a constant current source generating unit, a current magnitude adjustment unit, and a constant current source square wave output unit, wherein the power input unit is used to provide power supply, the high level control unit is connected to the power input unit and is used to control the high level generating part in the square wave signal, the low level control unit is connected to the high level control unit and the square wave output unit and is used to control the low level generating part in the square wave signal, the square wave output unit is connected to the constant current source generating unit and is used to transmit the square wave signal to the constant current source generating unit for power conversion, the current magnitude adjustment unit is connected to the constant current source generating unit and is used to control the magnitude of the constant current source current, and the constant current source square wave output unit is connected to the constant current source generating unit and is used to output the constant current source square wave signal generated by the constant current source generating unit to provide a load for use. The present invention realizes a constant current source square wave power supply circuit with complex functions and adjustable duty cycle and frequency by designing and using common electronic components to build the circuit. The circuit has low cost, low power consumption, and simple circuit board design and development. Moreover, the frequency and duty cycle of the square wave signal can be accurately adjusted by adjusting the high-level control unit and the low-level control unit, and precise control of the circuit signal can be achieved to improve the stability and response speed of the circuit system, thereby effectively improving the performance of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 : Principle block diagram of the constant current source square wave power supply circuit with adjustable duty cycle and frequency of the present invention;

[0022] Figure 2 : Principle block diagram of high-level control unit of constant current source square wave power supply circuit with adjustable duty cycle and frequency of the present invention;

[0023] Figure 3 : Schematic diagram of the low-level control unit of the constant current source square wave power supply circuit with adjustable duty cycle and frequency of the present invention;

[0024] Figure 4 : Principle block diagram of the square wave output unit of the constant current source square wave power supply circuit with adjustable duty cycle and frequency of the present invention;

[0025] Figure 5 : Principle block diagram of constant current source generating unit of constant current source square wave power supply circuit with adjustable duty cycle and frequency of the present invention;

[0026] Figure 6 : Circuit diagram of embodiment 1 of the present invention;

[0027] Figure 7 : Schematic diagram of a constant current source square wave signal generated by embodiment 1 of the present invention.

[0028] Description of labels:

[0029] 1. Power input unit; 2. High level control unit; 3. Low level control unit; 4. Square wave output unit; 5. Constant current source generating unit; 6. Current size adjustment unit; 7. Constant current source square wave output unit; 21. First current regulating module; 22. First charge storage module; 23. Second current limiting module; 24. Second N-type control module; 31. Fifth current regulating module; 32. Second charge storage module; 33. Fourth current limiting module; 34. Third N-type control module; 41. First P-type control module; 42. Third current limiting module; 51. Fourth P-type control module; 52. Fifth P-type control module. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0032] In order to keep the following description of the embodiments of the present invention clear and concise, the present invention omits detailed descriptions of some known functions and known components.

[0033] Please refer to the attached Figure 1-6 , one embodiment of the present invention is:

[0034] The present embodiment comprises a power input unit (1), a high level control unit (2), a low level control unit (3), a square wave output unit (4), a constant current source generating unit (5), a current magnitude adjusting unit (6), and a constant current source square wave output unit (7), wherein the power input unit (1) is connected to the high level control unit (2) and the square wave output unit (4), the high level control unit (2) is connected to the power input unit (1), the low level control unit (3), and the square wave output unit (4), and the low level control unit (3) is connected to the high level control unit (2), the square wave output unit (4), The constant current source generating unit (5) is connected; the square wave output unit (4) is connected to the power input unit (1), the high level control unit (2), the low level control unit (3), and the constant current source generating unit (5); the constant current source generating unit (5) is connected to the low level control unit (3), the square wave output unit (4), the current magnitude adjustment unit (6), and the constant current source square wave output unit (7); the current magnitude adjustment unit (6) is connected to the constant current source generating unit (5); the constant current source square wave output unit (7) is connected to the constant current source generating unit (5); the power input unit (1) is an input source module of the power supply.

[0035] The high-level control unit (2) comprises a first adjustable resistor R1, a first capacitor C1, a second resistor R2, and a second triode T2, wherein the first adjustable resistor R1 is connected to the first capacitor C1 and the second resistor R2, the first capacitor C1 is connected to the first adjustable resistor R1 and the second resistor R2, and the second resistor R2 is connected to the first adjustable resistor R1, the first capacitor C1, and the second triode T2.

[0036] The low-level control unit (3) comprises a fifth adjustable resistor R5, a second capacitor C2, a fourth resistor R4, and a third transistor T3, wherein the fifth adjustable resistor R5 is connected to the second capacitor C2 and the fourth resistor R4, the second capacitor C2 is connected to the fifth adjustable resistor R5 and the fourth resistor R4, and the fourth resistor R4 is connected to the fifth adjustable resistor R5, the second capacitor C2, and the third transistor T3.

[0037] The square wave output unit (4) comprises a first transistor T1 and a third resistor R3, wherein the first transistor T1 is connected to the third resistor R3.

[0038] The constant current source generating unit (5) comprises a fourth triode T4 and a fifth triode T5, wherein the fourth triode T4 is connected to the fifth triode T5.

[0039] The current magnitude adjustment unit (6) comprises a sixth resistor R6 and is a module for adjusting the magnitude of the output current.

[0040] The constant current source square wave output unit (7) is an output interface of the constant current source square wave power supply circuit.

[0041] The power input unit (1) is a unit that receives power transmitted from the front end and then provides power to the rear end high level control unit (2) and the square wave output unit (4).

[0042] The high-level control unit (2) controls the high-level part of the square wave signal, and adjusts the magnitude of the charging current of the first capacitor C1 through the first adjustable resistor R1. The magnitude of the charging current affects the time when the first capacitor C1 is charged. The second resistor R2 limits the current flowing through the second triode T2 to protect the second triode T2. The second triode T2 is controlled to be on and off according to the set parameters.

[0043] The low-level control unit (3) controls the low-level part of the square wave signal, and adjusts the magnitude of the charging current of the second capacitor C2 through the fifth adjustable resistor R5. The magnitude of the charging current affects the time when the second capacitor C2 is charged. The fourth resistor R4 limits the current flowing through the third triode T3 to protect the third triode T3. The third triode T3 is controlled to be on and off according to the set parameters.

[0044] The square wave output unit (4) is a unit for outputting a square wave signal. The first transistor T1 controls the on and off of the square wave signal output. The third resistor R3 limits the current flowing through the first transistor T1 to protect the first transistor T1.

[0045] The constant current source generating unit (5) performs constant current conversion on the current in the circuit, the fourth transistor T4 generates a reference current output by the constant current source, and the fifth transistor T5 generates the same current with reference to the reference current set by the fourth transistor T4 for use by subsequent circuits.

[0046] The sixth resistor of the current magnitude adjustment unit (6) sets the magnitude of the current generated by the constant current source generation unit (5).

[0047] The constant current source square wave output unit (7) outputs the constant current source square wave signal generated by the constant current source generating unit (5) to the outside.

[0048] Please refer to the attached Figure 6-7 The specific working principle of the first embodiment of the present invention is as follows:

[0049] The input power of the power input unit (1) is set to Vin. When Vin is powered on, it reaches R1, passes through R1 and then reaches C1, and C1 starts to charge. The initial voltage of C1 is set to V0. The voltage value that C1 can finally be charged to is V1. The voltage of C1 at a certain time t is Vt. The resistance value of R1 is Ra, and the capacitance value of C1 is Ca. Then, the time t1 for C1 to complete charging is t1=Ra*Ca×In[(V1-V0) / (V1-Vt)]. It can be known from the calculation formula that adjusting the resistance value of R1 can adjust the size of t1. As Vt increases, Vt will be applied to R2 at the same time, passing through R2 to reach T2.

[0050] When Vt meets the T2 turn-on voltage, T2 will turn on. At this time, Vin is applied to T1 and then T1 will turn on. T1 will output Vin high level. Vin is applied to R5 after passing through T1, and C2 is charged through R5. The initial voltage of C2 is set to V2, and the voltage that C2 can finally be charged to is V3. The voltage of C2 at a certain time t2 is Vt2, the resistance value of R5 is Rb, and the capacitance value of C2 is Cb. Then the charging time of C2 is t2=Rb*Cb×ln[(V3-V2) / (V3-Vt2)]. When Vt2 increases to the value that meets the opening value of T3, T3 will turn on. When T3 is turned on, T2 will turn off instantly. The closing of T2 will cause T1 to turn off instantly. At this time, the high level through T1 will change to a low level. At this time, the voltage Vt2 on C2 will pass through R4 to reach T3 for discharge. It is set that when Vt2 discharges to a voltage that does not meet the requirement for T3 to open, T3 will be closed. The time required at this time is t3. C1 will also discharge during the t3 time. When T3 is closed, C1 will continue to charge until T2 is opened. When T2 is opened, T1 will also be opened. When T1 is opened, it can output a high level again. The time when C1 continues to charge until T2 is opened is set to t4, so the low level time is t3+t4. After T1 outputs a high level, it will reach R5 and charge C2 through R5. At this time, a charge and discharge cycle is formed, and a square wave signal can be output from the square wave output unit. The duty cycle and frequency of the square wave signal can be set by adjusting the resistance values ​​of R1 and R5.

[0051] When the square wave signal is output from T1 of the square wave output unit and reaches the constant current source generating unit, the square wave signal will reach T4 and T5 at the same time. T4 is connected to R6. Since one end of R6 is connected to a low level, after the high level of the square wave signal reaches T4, T4 will be turned on. The magnitude of the current flowing through T4 can be set by adjusting R6. After R6 is set, the current passing through T4 is a constant current. Since T5 and T4 are connected at the common base, T4 is used as a reference, and T5 can also output the same constant current. Since T5 is connected to the constant current source square wave output unit (7), the constant current source square wave output unit (7) can output a constant current source square wave signal.

[0052] Based on the above principle, the constant current source square wave output unit can output a constant current source square wave signal with adjustable duty cycle and frequency; Figure 7 As shown: the horizontal axis is time t, the vertical axis is voltage V, the high level time in one signal cycle is t2, and the low level time is t3+t4, then the duty cycle = t2 / (t2+t3+t4), frequency = 1 / (t2+t3+t4), from the formula we can see that the size of t2 can be adjusted by the high level control unit, and the size of t3+t4 can be adjusted by the low level control unit, so the duty cycle and frequency of the constant current source square wave signal can be adjusted.

[0053] In summary, the present invention realizes a constant current source square wave power supply circuit with complex functions and adjustable duty cycle and frequency by designing and using common electronic components to build the circuit. It has low cost, low power consumption, and simple circuit board design and development. Moreover, by adjusting the high-level control unit and the low-level control unit, the frequency and duty cycle of the square wave signal can be accurately adjusted, and precise control of the circuit signal can be achieved to improve the stability and response speed of the circuit system, thereby effectively improving the performance of the circuit.

[0054] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A constant current source square wave power supply circuit with adjustable duty cycle and frequency, comprising a power input unit, a high level control unit, a low level control unit, a square wave output unit, a constant current source generating unit, a current size adjusting unit, and a constant current source square wave output unit, characterized in that: The power input unit is connected to the high level control unit and the square wave output unit, the high level control unit is connected to the power input unit, the low level control unit, and the square wave output unit, the low level control unit is connected to the high level control unit, the square wave output unit, and the constant current source generating unit, the square wave output unit is connected to the power input unit, the high level control unit, the low level control unit, and the constant current source generating unit, the constant current source generating unit is connected to the low level control unit, the square wave output unit, the current size adjustment unit, and the constant current source square wave output unit, the current size adjustment unit is connected to the constant current source generating unit, the constant current source square wave output unit is connected to the constant current source generating unit, The power input unit is a power supply input source module, which is used to receive the power transmitted from the front end and provide power supply to the rear end high level control unit and square wave output unit. The current size adjustment unit is a module for adjusting the output current size. The current size adjustment unit sets the current size generated by the constant current source generating unit. The constant current source square wave output unit is the output interface of the constant current source square wave power supply circuit. The constant current source square wave output unit outputs the constant current source square wave signal generated by the constant current source generating unit to the outside.

2. The constant current source square wave power supply circuit with adjustable duty cycle and frequency according to claim 1, characterized in that: The high-level control unit comprises a first current regulating module, a first charge storage module, a second current limiting module, and a second N-type control module, wherein the first current regulating module is connected to the first charge storage module and the second current limiting module, the first charge storage module is connected to the first current regulating module and the second current limiting module, the second current limiting module is connected to the first current regulating module, the first charge storage module, and the second N-type control module, and the second N-type control module (24) is connected to the second current limiting module (23).

3. The constant current source square wave power supply circuit with adjustable duty cycle and frequency according to claim 1, characterized in that: The low-level control unit comprises a fifth current regulating module, a second charge storage module, a fourth current limiting module, and a third N-type control module, wherein the fifth current regulating module is connected to the second charge storage module and the fourth current limiting module, the second charge storage module is connected to the fifth current regulating module and the fourth current limiting module, the fourth current limiting module is connected to the fifth current regulating module, the second charge storage module, and the third N-type control module, and the third N-type control module (34) is connected to the fourth current limiting module (33).

4. The constant current source square wave power supply circuit with adjustable duty cycle and frequency according to claim 1, characterized in that: The square wave output unit includes a first P-type control module and a third current limiting module, wherein the first P-type control module is connected to the third current limiting module.

5. The constant current source square wave power supply circuit with adjustable duty cycle and frequency according to claim 1, characterized in that: The constant current source generating unit comprises a fourth P-type control module and a fifth P-type control module, wherein the fourth P-type control module is connected to the fifth P-type control module.

6. The constant current source square wave power supply circuit with adjustable duty cycle and frequency according to claim 2, characterized in that: The high-level control unit controls the high-level part of the square wave signal, and adjusts the size of the charging current of the first charge storage module through the first current regulation module. The size of the charging current affects the time when the first charge storage module is charged. The second current limiting module limits the current flowing through the second N-type control module to protect the second N-type control module. The second N-type control module performs on-off control according to the set parameters.

7. The constant current source square wave power supply circuit with adjustable duty cycle and frequency according to claim 3, characterized in that: The low-level control unit controls the low-level part of the square wave signal, and adjusts the size of the charging current of the second charge storage module through the fifth current regulation module. The size of the charging current affects the time when the second charge storage module is charged. The fourth current limiting module limits the current flowing through the third N-type control module to protect the third N-type control module. The third N-type control module performs on-off control according to the set parameters.

8. The constant current source square wave power supply circuit with adjustable duty cycle and frequency according to claim 4, characterized in that: The square wave output unit is a unit that outputs a square wave signal. The first P-type control module controls the on and off of the square wave signal output. The third current limiting module limits the current flowing through the first P-type control module to protect the first P-type control module.

9. The constant current source square wave power supply circuit with adjustable duty cycle and frequency according to claim 5, characterized in that: The constant current source generating unit performs constant current conversion on the current in the circuit, the fourth P-type control module generates a reference current output by the constant current source, and the fifth P-type control module generates the same current with reference to the reference current set by the fourth P-type control module for use by subsequent circuits.

10. The constant current source square wave power supply circuit with adjustable duty cycle and frequency according to claim 1, characterized in that: The frequency and duty cycle of the constant current source square wave signal can be adjusted by setting the parameters of the high level control unit and the low level control unit.

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