Miniaturized isolation power supply circuit and switching power supply

Abstract

The utility model is suitable for the technical field of switching power supplies, and provides a miniaturized isolation power supply circuit and a switching power supply. The circuit comprises a square wave generation module, an isolation conversion module and a rectification and voltage stabilization module. The in-phase input end of the square wave generation module is used for converting a preset power supply voltage into a first voltage, the inverted input end of the square wave generation module is used for converting the preset power supply voltage into a second voltage, the output end of the square wave generation module is connected with the in-phase input end and the inverted input end, and the square wave generation module is used for outputting a high level or a low level according to a comparison result of the first voltage and the second voltage; the first input end of the isolation transformation module is connected with the output end of the square wave generation module, the second input end is grounded, the first output end is connected with the first input end of the rectification and voltage stabilization module, and the second output end is connected with the second input end of the rectification and voltage stabilization module; the first output end of the rectifying and voltage-stabilizing module is used for outputting isolation voltage, and the second output end is grounded. According to the embodiment of the utility model, the circuit structure and size of the isolation power supply circuit can be simplified.

Description

Technical Field

[0001] The utility model belongs to the technical field of switching power supplies, and in particular relates to a miniaturized isolation power supply circuit and a switching power supply. Background Art

[0002] Switching power supplies often require multiple voltage levels, and many require isolated power supply. Examples include powering the driver circuits of switching transistors, isolated power supply for CAN communication, or powering isolated sampling circuits. This type of isolated power supply circuit is characterized by its wide application range, minimal size, and minimal component count.

[0003] Existing isolated power supply circuit solutions mainly use analog chip control or digital chip control. The circuit can use flyback circuit or forward circuit. However, Figure 1 As shown, no matter whether analog chips or digital chips are used, the isolated power supply circuit is relatively complex and has a large circuit volume. Utility Model Content

[0004] In view of this, an embodiment of the present invention provides a miniaturized isolated power supply circuit and a switching power supply to solve the problems of the current isolated power supply circuit having a complex structure and a large circuit volume.

[0005] A first aspect of an embodiment of the present utility model provides a miniaturized isolated power supply circuit, comprising: a square wave generating module, an isolation conversion module, and a rectification and voltage stabilization module;

[0006] The square wave generating module has a non-inverting input terminal for converting a preset power supply voltage into a first voltage, an inverting input terminal for converting the preset power supply voltage into a second voltage, and an output terminal connected to the non-inverting input terminal and the inverting input terminal, respectively, for outputting a high level or a low level according to a comparison result of the first voltage and the second voltage;

[0007] The isolation conversion module has a first input end connected to the output end of the square wave generating module, a second input end connected to the ground, a first output end connected to the first input end of the rectifying and voltage stabilizing module, and a second output end connected to the second input end of the rectifying and voltage stabilizing module;

[0008] The rectifier and voltage stabilization module has a first output terminal for outputting an isolated voltage, and a second output terminal for grounding.

[0009] In a possible implementation, the square wave generating module includes: a first RC unit, a second RC unit, a comparator, and a feedback unit;

[0010] The first RC unit is connected to the non-inverting input terminal of the comparator, and is used to convert the preset power supply voltage into a first voltage;

[0011] A first end of the second RC unit is connected to the inverting input end of the comparator, and a second end of the second RC unit is connected to the output end of the comparator and the feedback unit respectively, for converting the preset power supply voltage into a second voltage;

[0012] The feedback unit is also connected to the non-inverting input terminal of the comparator;

[0013] The output end of the comparator serves as the output end of the square wave generating module.

[0014] In a possible implementation, the first RC unit includes: a resistor R1, a resistor R2, and a capacitor C1;

[0015] One end of the resistor R1 is used to connect to a preset power supply voltage, and the other end of the resistor R1 is connected to one end of the resistor R2 and one end of the capacitor C1 and then connected to the non-inverting input end of the comparator;

[0016] The other end of the resistor R2 and the other end of the capacitor C1 are connected and then grounded.

[0017] In a possible implementation, the second RC unit includes: a resistor R3, a resistor R4, and a capacitor C2;

[0018] One end of the resistor R3 is used to connect to a preset power supply voltage, and the other end of the resistor R3 is respectively connected to the output end of the comparator, the feedback unit and one end of the resistor R4;

[0019] The other end of the resistor R4 is connected to one end of the capacitor C2 and then connected to the inverting input end of the comparator;

[0020] The other end of the capacitor C2 is grounded.

[0021] In a possible implementation, the feedback unit includes: a resistor R5;

[0022] One end of the resistor R5 is connected to the non-inverting input end of the comparator, and the other end of the resistor R5 is connected to the output end of the comparator and the second end of the second RC unit respectively.

[0023] In a possible implementation, the isolation conversion module includes: a capacitor C3 and a transformer T1;

[0024] One end of the capacitor C3 is connected to the output end of the square wave generating module, and the other end of the capacitor C3 is connected to the first end of the primary winding of the transformer T1;

[0025] The second end of the primary winding of the transformer T1 is grounded, the first end of the secondary winding of the transformer is connected to the first input end of the rectifier and voltage regulator module, and the second end of the secondary winding of the transformer is connected to the second input end of the rectifier and voltage regulator module.

[0026] In a possible implementation, the rectifier and voltage stabilization module includes: a rectifier diode D1, a switch tube Q1, a capacitor C4, a resistor R6, a voltage stabilizing diode D2, and a capacitor C5;

[0027] One end of the rectifier diode D1 is connected to the first output end of the isolation conversion module, and the other end of the rectifier diode D1 is connected to the collector of the switch tube Q1, one end of the capacitor C4 and one end of the resistor R6 respectively;

[0028] The base of the switch tube Q1 is connected to the other end of the resistor R6 and one end of the voltage stabilizing diode D2 respectively, and the emitter of the switch tube Q1 is connected to one end of the capacitor C5 for outputting an isolation voltage;

[0029] The other end of the capacitor C4 is connected to the other end of the voltage stabilizing diode D2 and then connected to the second output end of the isolation conversion module;

[0030] The other end of the capacitor C5 and the other end of the voltage stabilizing diode D2 are connected and then grounded.

[0031] A second aspect of an embodiment of the present invention provides a switching power supply, comprising the miniaturized isolated power supply circuit in the first aspect and any possible implementation of the first aspect.

[0032] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: the embodiments of the present invention generate a stable square wave with controllable frequency and duty cycle through a square wave generating module, realize the isolation function through an isolation conversion module, and stabilize the rectified DC voltage to a set value through a rectification and voltage stabilization module to supply power to the power supply equipment. The circuit is simple and uses fewer devices, which can simplify the circuit structure and volume of the isolated power supply circuit and more reliably realize the function of the isolated power supply circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0034] Figure 1This is a schematic structural diagram of an isolated power supply circuit in the prior art provided by an embodiment of the present utility model;

[0035] Figure 2 It is a structural diagram of a miniaturized isolated power supply circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0036] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present invention with unnecessary detail.

[0037] In order to illustrate the technical solution of the present invention, specific embodiments are provided below.

[0038] Combine Figure 2 As shown, the miniaturized isolated power supply circuit provided by the embodiment of the present utility model includes: a square wave generating module 10, an isolation conversion module 20 and a rectification and voltage stabilization module 30;

[0039] Among them, the square wave generating module 10, the non-inverting input terminal is used to convert the preset power supply voltage into a first voltage, the inverting input terminal is used to convert the preset power supply voltage into a second voltage, and the output terminal is connected to the non-inverting input terminal and the inverting input terminal respectively, and is used to output a high level or a low level according to the comparison result of the first voltage and the second voltage.

[0040] The isolation conversion module 20 has a first input end connected to the output end of the square wave generating module 10 , a second input end grounded, a first output end connected to the first input end of the rectifying and voltage stabilizing module 30 , and a second output end connected to the second input end of the rectifying and voltage stabilizing module 30 .

[0041] The rectifier and voltage stabilization module 30 has a first output terminal for outputting an isolated voltage and a second output terminal connected to ground.

[0042] In this embodiment, the square wave generating module forms a self-excited oscillation circuit based on a comparator. The self-excited oscillation circuit periodically changes the relative size of the first voltage and the second voltage converted from the preset power supply voltage, so that according to the difference in the relative size of the first voltage and the second voltage, the comparator periodically outputs a high level or a low level, thereby generating a stable square wave with controllable frequency and duty cycle through the square wave generating module, and realizing the isolation function through the subsequent isolation conversion module, and stabilizing the rectified DC voltage to a set value through the rectification and voltage stabilization module to power the power supply equipment, thereby realizing the function of the isolated power supply circuit more reliably through a simple circuit structure and fewer components, and realizing different output voltages by modifying the circuit parameters of the isolation conversion module and the rectification and voltage stabilization module, which is easy to use.

[0043] Optional, combined Figure 2 As shown, the square wave generating module 10 includes: a first RC unit, a second RC unit, a comparator U1 and a feedback unit.

[0044] The first RC unit is connected to the non-inverting input terminal of the comparator U1 and is used to convert the preset power supply voltage into a first voltage.

[0045] A first end of the second RC unit is connected to the inverting input end of the comparator U1 , and a second end of the second RC unit is connected to the output end of the comparator U1 and the feedback unit respectively, for converting the preset power supply voltage into a second voltage.

[0046] The feedback unit is also connected to the non-inverting input terminal of the comparator U1.

[0047] The output end of the comparator U1 serves as the output end of the square wave generating module 10 .

[0048] Exemplarily, the first RC unit may include a resistor R1 , a resistor R2 , and a capacitor C1 .

[0049] Among them, one end of the resistor R1 is used to connect to the preset power supply voltage, and the other end of the resistor R1 is connected to one end of the resistor R2 and one end of the capacitor C1 and then connected to the non-inverting input end of the comparator U1; the other end of the resistor R2 and the other end of the capacitor C1 are connected to ground.

[0050] Exemplarily, the second RC unit may include a resistor R3, a resistor R4, and a capacitor C2.

[0051] Among them, one end of the resistor R3 is used to connect to the preset power supply voltage, and the other end of the resistor R3 is respectively connected to the output end of the comparator U1, the feedback unit and one end of the resistor R4; the other end of the resistor R4 is connected to one end of the capacitor C2 and then connected to the inverting input end of the comparator U1; the other end of the capacitor C2 is grounded.

[0052] Exemplarily, the feedback unit may include: a resistor R5.

[0053] One end of the resistor R5 is connected to the non-inverting input end of the comparator U1 , and the other end of the resistor R5 is connected to the output end of the comparator U1 and the second end of the second RC unit respectively.

[0054] For example, in this embodiment, a self-excited oscillation circuit is formed using a single comparator. After power-on, if the 4-pin +IN (i.e., the non-inverting input) of comparator U1 is high, the 3-pin -IN (i.e., the inverting input) is low, and the 1-pin OUT (i.e., the output) is high resistance, the output is high. At this time, the +5V preset power supply voltage charges capacitor C2 through resistor R3 until the 3-pin -IN voltage exceeds the 4-pin +IN, and the 1-pin OUT becomes a low resistance state, and the output is low. Then, capacitor C2 discharges through resistor R4 until the 3-pin -IN voltage is lower than the 4-pin +IN voltage, repeating the previous state, so that the square wave generator module outputs a +5V square wave waveform.

[0055] Optionally, the isolation conversion module 20 includes: capacitor C3 and transformer T1.

[0056] One end of the capacitor C3 is connected to the output end of the square wave generating module 10 , and the other end of the capacitor C3 is connected to the first end of the primary winding of the transformer T1 .

[0057] The second end of the primary winding of the transformer T1 is grounded, the first end of the secondary winding of the transformer is connected to the first input end of the rectifier and voltage regulator module, and the second end of the secondary winding of the transformer is connected to the second input end of the rectifier and voltage regulator module.

[0058] In this embodiment, the capacitor C3 plays a role in isolating DC power. Taking the square wave generating module generating a +5V square wave as an example, the +5V square wave is converted into a ±2.5V square wave through the isolation conversion module.

[0059] Optionally, the rectifier and voltage stabilization module 30 includes: a rectifier diode D1, a switch tube Q1, a capacitor C4, a resistor R6, a voltage stabilization diode D2 and a capacitor C5.

[0060] One end of the rectifier diode D1 is connected to the first output end of the isolation conversion module 20 , and the other end of the rectifier diode D1 is connected to the collector C of the switch tube Q1 , one end of the capacitor C4 and one end of the resistor R6 .

[0061] The base B of the switch tube Q1 is connected to the other end of the resistor R6 and one end of the voltage stabilizing diode D2 respectively, and the emitter E of the switch tube Q1 is connected to one end of the capacitor C5 for outputting an isolation voltage.

[0062] The other end of the capacitor C4 is connected to the other end of the voltage stabilizing diode D2 and then connected to the second output end of the isolation conversion module 20 .

[0063] The other end of the capacitor C5 and the other end of the voltage stabilizing diode D2 are connected and then grounded.

[0064] In this embodiment, the rectifier diode D1 in the rectifier and voltage stabilization module 30 performs a rectifying function, converting the AC power (eg, ±2.5V square wave) generated by the isolation conversion module 20 into DC power, and stabilizing the converted DC power.

[0065] For example, assuming that the output voltage is 5V, the Zener diode D2 can be a 5.6V Zener diode. At this time, the Zener diode clamps the base B4 of the switch tube Q1 at 5.6V, and the output isolation voltage is 5.6V minus the base-emitter BE voltage drop, which is 5V. The remaining voltage is applied to both ends of the resistor R6.

[0066] In the embodiment of the utility model, a stable square wave with controllable frequency and duty cycle is generated through a square wave generating module, an isolation function is realized through an isolation conversion module, and the rectifier and voltage stabilization module stabilizes the rectified DC voltage to a set value to supply power to the power supply equipment. The circuit is simple and uses fewer devices, which can simplify the circuit structure and volume of the isolated power supply circuit and more reliably realize the function of the isolated power supply circuit.

[0067] As another embodiment of the present invention, the present invention also includes a switching power supply, including the miniaturized isolated power supply circuit of any of the above embodiments, and has the same beneficial effects as the miniaturized isolated power supply circuit described in any of the above embodiments, which will not be repeated here.

[0068] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A miniaturized isolated power supply circuit, characterized in that: include: Square wave generation module, isolation conversion module and rectification and voltage regulation module; The square wave generating module has a non-inverting input terminal for converting a preset power supply voltage into a first voltage, an inverting input terminal for converting the preset power supply voltage into a second voltage, and an output terminal connected to the non-inverting input terminal and the inverting input terminal, respectively, for outputting a high level or a low level according to a comparison result of the first voltage and the second voltage; The isolation conversion module has a first input end connected to the output end of the square wave generating module, a second input end connected to the ground, a first output end connected to the first input end of the rectifying and voltage stabilizing module, and a second output end connected to the second input end of the rectifying and voltage stabilizing module; The rectifier and voltage stabilization module has a first output terminal for outputting an isolated voltage, and a second output terminal for grounding.

2. The miniaturized isolated power supply circuit according to claim 1, wherein: The square wave generating module includes: a first RC unit, a second RC unit, a comparator and a feedback unit; The first RC unit is connected to the non-inverting input terminal of the comparator, and is used to convert the preset power supply voltage into a first voltage; A first end of the second RC unit is connected to the inverting input end of the comparator, and a second end of the second RC unit is connected to the output end of the comparator and the feedback unit respectively, for converting the preset power supply voltage into a second voltage; The feedback unit is also connected to the non-inverting input terminal of the comparator; The output end of the comparator serves as the output end of the square wave generating module.

3. The miniaturized isolated power supply circuit according to claim 2, wherein: The first RC unit includes: a resistor R1, a resistor R2 and a capacitor C1; One end of the resistor R1 is used to connect to a preset power supply voltage, and the other end of the resistor R1 is connected to one end of the resistor R2 and one end of the capacitor C1 and then connected to the non-inverting input end of the comparator; The other end of the resistor R2 and the other end of the capacitor C1 are connected and then grounded.

4. The miniaturized isolated power supply circuit according to claim 2, wherein: The second RC unit includes: a resistor R3, a resistor R4 and a capacitor C2; One end of the resistor R3 is used to connect to a preset power supply voltage, and the other end of the resistor R3 is respectively connected to the output end of the comparator, the feedback unit and one end of the resistor R4; The other end of the resistor R4 is connected to one end of the capacitor C2 and then connected to the inverting input end of the comparator; The other end of the capacitor C2 is grounded.

5. The miniaturized isolated power supply circuit according to claim 2, wherein: The feedback unit includes: a resistor R5; One end of the resistor R5 is connected to the non-inverting input end of the comparator, and the other end of the resistor R5 is connected to the output end of the comparator and the second end of the second RC unit respectively.

6. The miniaturized isolated power supply circuit according to claim 1, wherein: The isolation conversion module includes: a capacitor C3 and a transformer T1; One end of the capacitor C3 is connected to the output end of the square wave generating module, and the other end of the capacitor C3 is connected to the first end of the primary winding of the transformer T1; The second end of the primary winding of the transformer T1 is grounded, the first end of the secondary winding of the transformer is connected to the first input end of the rectifier and voltage regulator module, and the second end of the secondary winding of the transformer is connected to the second input end of the rectifier and voltage regulator module.

7. The miniaturized isolated power supply circuit according to claim 1, wherein: The rectifier and voltage stabilization module includes: a rectifier diode D1, a switch tube Q1, a capacitor C4, a resistor R6, a voltage stabilizing diode D2 and a capacitor C5; One end of the rectifier diode D1 is connected to the first output end of the isolation conversion module, and the other end of the rectifier diode D1 is connected to the collector of the switch tube Q1, one end of the capacitor C4 and one end of the resistor R6 respectively; The base of the switch tube Q1 is connected to the other end of the resistor R6 and one end of the voltage stabilizing diode D2 respectively, and the emitter of the switch tube Q1 is connected to one end of the capacitor C5 for outputting an isolation voltage; The other end of the capacitor C4 is connected to the other end of the voltage stabilizing diode D2 and then connected to the second output end of the isolation conversion module; The other end of the capacitor C5 and the other end of the voltage stabilizing diode D2 are connected and then grounded.

8. A switching power supply, characterized in that: The device comprises the miniaturized isolated power supply circuit as described in any one of claims 1 to 7.

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