Wide time delay power supply protection circuit based on PPTC resettable fuse

Abstract

The utility model relates to the technical field of electronics, in particular to a wide time delay power supply protection circuit based on PPTC resettable fuses, which comprises a wide time delay power supply and a load circuit, and corresponding resettable fuses and MOS (Metal Oxide Semiconductor) tubes are connected in series between a driving control circuit and each motor. A first resettable fuse and a second resettable fuse are welded on a circuit board of the wide delay power supply, and the drive control circuit comprises a power supply module, a sampling circuit module, a threshold analysis module and an execution protection module. According to the utility model, the on-off control under different currents is realized by adjusting the overcurrent protection circuit, the application is flexible and convenient, and a good overcurrent protection function is provided for electronic equipment needing overcurrent protection.

Description

Technical Field

[0001] The utility model relates to the field of electronic technology, in particular to a wide-time-delay power supply protection circuit based on a PPTC resettable fuse. Background Art

[0002] A wide-time delay power supply is a special power supply designed to adapt to the special working conditions of the load circuit. Various load devices, especially those working with multiple motors, have requirements for both short-term high-current operation and long-term small and medium-current operation, so overcurrent protection circuits are needed.

[0003] Traditional bimetallic heating and deformation methods, which mechanically disconnect circuits, rely primarily on the properties of a bimetallic strip. This strip is composed of two or more metals with different thermal expansion coefficients. When the temperature changes, the different thermal expansion coefficients of the component layers cause the bimetallic strip to bend and deform. However, this method has the disadvantages of slow response, significant temperature dependence, and inability to precisely control the delay disconnection time. Utility Model Content

[0004] The purpose of the utility model is to provide a wide-time-delay power supply protection circuit based on a PPTC resettable fuse, that is, a resettable fuse is added and an overcurrent protection switch is provided. Through the overcurrent protection circuit, the time of delayed disconnection can be accurately controlled to avoid malfunction of the switch due to current fluctuations in the circuit.

[0005] In order to achieve the above-mentioned objectives, the present invention adopts the following technical solutions: a wide-delay power supply protection circuit based on a PPTC resettable fuse, comprising a wide-delay power supply and a load circuit, wherein the load circuit comprises multiple motors and a drive control circuit, a corresponding resettable fuse and a MOS tube are connected in series between the drive control circuit and each motor, a first resettable fuse and a second resettable fuse are welded on the circuit board of the wide-delay power supply, and the drive control circuit comprises a power supply module, a sampling circuit module, a threshold analysis module and an execution protection module.

[0006] Furthermore, the power supply module includes a transient suppression diode D4, a switch K1, a first filtering circuit, a three-terminal voltage regulator IC1 and a second filtering circuit which are connected in sequence.

[0007] The first filtering circuit includes a capacitor C5 and a capacitor C6 connected in parallel, and the second filtering circuit includes a capacitor C3 and a capacitor C4 connected in parallel.

[0008] Furthermore, the sampling circuit module includes a transient suppression diode D3, a sampling resistor RQ, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a first operational amplifier UIA and a transistor Q1. The transient suppression diode D3 is connected to the node between the switch K1 and the sampling resistor RQ. The sampling resistor RQ is connected in series with the resistors R2, R3 and R4. The positive electrode of the first operational amplifier UIA is connected to the resistor R3, and the negative electrode is connected to the resistor R4. The base of the transistor Q1 is connected to the resistor R5, the collector is connected to the first operational amplifier UIA, and the emitter is connected to the resistor R6. The resistor R5 is connected to the node between the resistors R2 and R3.

[0009] Furthermore, the threshold analysis module includes a first comparator U2A, a second comparator U2B, a third comparator U2C, a capacitor C1, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor R21, a resistor R22 and a resistor R24, the positive electrode of the first comparator U2A is connected to the sampling circuit module through the resistor R10, the negative electrode of the first comparator U2A is grounded after passing through R11 and R8 in parallel, one end of the resistor R7 is connected to the node of the resistor R8 and the resistor R11, and the other end is connected to the output end of the first comparator U2A through the series resistor R16, and the second comparator U The positive electrode of the capacitor C1 is connected to the sampling circuit module through the resistor R18, and the negative electrode is connected to the node of the resistor R9 and the resistor R20. The positive electrode of the capacitor C1 is connected to the resistor R18, and the negative electrode is connected to the node of the resistor R9 and the resistor R20. The positive electrode and the output end of the third comparator U2C are connected in parallel with a resistor R21. The resistor R22, the resistor R17, and the resistor R25 are connected in series and connected to the resistor R18 and the output end of the third comparator U2C.

[0010] Furthermore, the execution protection module includes a transistor Q2, a diode D1, a diode D2 and a load, the base of the transistor Q2 is connected to the load, the collector is connected to the node of the transient suppression diode D1 and the transient suppression diode D2, and the emitter is grounded, and the transient suppression diode D1 and the transient suppression diode D2 are respectively connected to the threshold analysis module.

[0011] This utility model achieves on-off control under different currents by adjusting the overcurrent protection circuit. It is flexible and convenient to use, providing excellent overcurrent protection for electronic equipment that requires it. It can also be used as a common toggle switch under normal current. The provision of multiple resettable fuses provides overcurrent and overtemperature protection for the load, improving equipment reliability and perfectly resolving safety issues while simplifying the design. It also reduces design, material, and production testing costs, and effectively extends the life of various load equipment systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a circuit diagram of the utility model;

[0013] Figure 2 This is a schematic diagram of the power module of the present utility model;

[0014] Figure 3 This is a schematic diagram of the sampling circuit module of the present utility model;

[0015] Figure 4 This is a schematic diagram of the threshold analysis module of the present utility model;

[0016] Figure 5 This is a schematic diagram of the execution protection module of the utility model. DETAILED DESCRIPTION

[0017] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be provided below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to facilitate a more thorough and comprehensive understanding of the disclosure of the present invention.

[0018] It should be noted that when an element is referred to as being “fixed to” another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or there may be an intermediate element.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0020] See also Figures 1 to 5A wide-delay power switch protection circuit based on a PPTC resettable fuse includes a wide-delay power supply and a load circuit. The load circuit includes multiple motors and a drive control circuit. A corresponding resettable fuse and MOS transistor are connected in series between the drive control circuit and each motor. A first resettable fuse PPTC1 and a second resettable fuse PPTC2 are soldered to the wide-delay power supply circuit board. The drive control circuit includes a power module, a sampling circuit module, a threshold analysis module, and an execution protection module. MOS transistors Q1-Q4 and PPTC3-PPTC6 are essentially located on the control board within the drive control circuit. They are drawn outside for visual clarity and to enhance the intuitive relationship between them. Similarly, PPTC1 and PPTC2 are located on the wide-delay power supply circuit board.

[0021] The power module includes a transient suppression diode (TVS) D4, a switch K1, a first filter circuit, a three-terminal voltage regulator IC1, and a second filter circuit, all connected in sequence. The first filter circuit includes capacitors C5 and C6 connected in parallel, while the second filter circuit includes capacitors C3 and C4 connected in parallel. After the power supply voltage is input through the electrical connector socket, it passes through TVS diode D4 to protect against voltage spikes in the circuit. After filtering the input voltage through capacitors C5 and C6, the three-terminal voltage regulator IC1 stabilizes the input voltage to 5V. It is then filtered by capacitors C3 and C4 to provide the power supply voltage for operational amplifier U1 and comparator U2.

[0022] The sampling circuit module includes a transient suppression diode D3, a sampling resistor RQ, resistors R2, R3, R4, R5, R6, a first operational amplifier UIA, and a transistor Q1. Transient suppression diode D3 is connected to the node between switch K1 and sampling resistor RQ. Sampling resistor RQ is connected in series with resistors R2, R3, and R4. The positive electrode of the first operational amplifier UIA is connected to resistor R3, and the negative electrode is connected to resistor R4. The base of transistor Q1 is connected to resistor R5, the collector is connected to the first operational amplifier UIA, and the emitter is connected to resistor R6. Resistor R5 is connected to the node between resistors R2 and R3. During normal operation, the sampling resistor RQ is converted into a voltage by the current in the sampling circuit. Due to the characteristics of virtual short and virtual open of the operational amplifier, the voltage across resistor R2 is equal to the voltage across RQ, that is, U RQ =U R2 , and I R2 =I R6 , then U R2 / U RQ =R6 / R2, the on-off node of the overcurrent protection switch can be controlled by controlling the current range flowing through the precision resistor RQ.

[0023] The threshold analysis module includes a first comparator U2A, a second comparator U2B, a third comparator U2C, a capacitor C1, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor R21, a resistor R22 and a resistor R24. The positive electrode of the first comparator U2A is connected to the sampling circuit module through the resistor R10, and the negative electrode of the first comparator U2A is grounded after passing through R11 and R8 in parallel. One end of the resistor R7 is connected to the node of the resistor R8 and the resistor R11, and the other end is connected to the output end of the first comparator U2A through the series resistor R16. The positive electrode of the comparator U2B is connected to the sampling circuit module through the resistor R13, the negative electrode of the second comparator U2B is connected to the resistors R14 and R9 connected in series, one end of the resistor R24 ​​is connected to the node of R14 and R9, and the other end is connected to the node of resistors R7 and R16, the positive electrode of the third comparator U2C is connected to the second comparator U2B through the resistor R18, the negative electrode of the third comparator U2C is connected to the node of resistors R19 and R20, the positive electrode of the capacitor C1 is connected to the resistor R18, and the negative electrode is connected to the node of the resistor R9 and the resistor R20, the positive electrode and the output end of the third comparator U2C are connected in parallel with the resistor R21, and the resistors R22, R17, and R25 are connected in series and connected to the resistor R18 and the output end of the third comparator U2C. The voltage output by the sampling circuit module is used as the non-inverting input terminal of the comparators U2A and U2B. The voltage of the inverting input terminal of U2A is obtained by dividing the 5V voltage output by the voltage regulator by resistors R7 and R8. The resistance value of the resistor is adjusted according to actual needs to control the current value of the instantaneous disconnection of the switch; the voltage of the inverting input terminal of U2A is obtained by dividing the 5V voltage output by the voltage regulator by resistors R9 and R24. The resistance value of the resistor is adjusted according to actual needs to control the current value of the delayed disconnection of the switch.

[0024] The execution protection module includes transistor Q2, diode D1, diode D2, and a load. The base of transistor Q2 is connected to the load, the collector is connected to the junction of TVS diodes D1 and D2, and the emitter is grounded. TVS diodes D1 and D2 are connected to the threshold analysis module. Its primary function is to direct the comparator output voltage of the threshold analysis circuit through unidirectional diodes D1 and D2 to transistor Q2. The switching characteristics of the transistor control the energized operating state of the trip unit, preventing damage to downstream circuits due to improper operation.

[0025] The above-described embodiments merely represent several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present utility model patent shall be determined by the appended claims.

Claims

1. A wide-time-delay power supply protection circuit based on a PPTC resettable fuse, characterized by: The invention comprises a wide-delay power supply and a load circuit. The load circuit comprises multiple motors and a drive control circuit. A corresponding resettable fuse and MOS tube are connected in series between the drive control circuit and each motor. A first resettable fuse and a second resettable fuse are welded on the circuit board of the wide-delay power supply. The drive control circuit comprises a power supply module, a sampling circuit module, a threshold analysis module, and an execution protection module.

2. The wide time delay power supply protection circuit based on PPTC resettable fuse according to claim 1, characterized in that: The power supply module includes a transient suppression diode D4, a switch K1, a first filtering circuit, a three-terminal voltage regulator IC1 and a second filtering circuit which are connected in sequence.

3. The wide time delay power supply protection circuit based on PPTC resettable fuse according to claim 2, characterized in that: The first filtering circuit includes a capacitor C5 and a capacitor C6 connected in parallel, and the second filtering circuit includes a capacitor C3 and a capacitor C4 connected in parallel.

4. The wide time delay power supply protection circuit based on PPTC resettable fuse according to claim 1, characterized in that: The sampling circuit module includes a transient suppression diode D3, a sampling resistor RQ, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a first operational amplifier UIA, and a transistor Q1. The transient suppression diode D3 is connected to the node between the switch K1 and the sampling resistor RQ. The sampling resistor RQ is connected in series with the resistors R2, R3, and R4. The positive electrode of the first operational amplifier UIA is connected to the resistor R3, and the negative electrode is connected to the resistor R4. The base of the transistor Q1 is connected to the resistor R5, the collector is connected to the first operational amplifier UIA, and the emitter is connected to the resistor R6. The resistor R5 is connected to the node between the resistors R2 and R3.

5. The wide time delay power supply protection circuit based on PPTC resettable fuse according to claim 1, characterized in that: The threshold analysis module includes a first comparator U2A, a second comparator U2B, a third comparator U2C, a capacitor C1, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor R21, a resistor R22 and a resistor R24. The positive electrode of the first comparator U2A is connected to the sampling circuit module through the resistor R10, and the negative electrode of the first comparator U2A is grounded after passing through the parallel resistors R11 and R8. One end of the resistor R7 is connected to the node of the resistor R8 and the resistor R11, and the other end is connected to the output end of the first comparator U2A through the series resistor R16. The positive electrode of the second comparator U2B is connected to the sampling circuit module through the resistor R10. The positive electrode is connected to the sampling circuit module through the resistor R13, the negative electrode of the second comparator U2B is connected to the resistors R14 and R9 in series, one end of the resistor R24 ​​is connected to the node of the R14 and R9, and the other end is connected to the node of the resistors R7 and R16, the positive electrode of the third comparator U2C is connected to the second comparator U2B through the resistor R18, the negative electrode of the third comparator U2C is connected to the node of the resistors R19 and R20, the positive electrode of the capacitor C1 is connected to the resistor R18, and the negative electrode is connected to the node of the resistor R9 and the resistor R20, the positive electrode and the output end of the third comparator U2C are connected in parallel with the resistor R21, and the resistors R22, R17, and R25 are connected in series and connected to the resistor R18 and the output end of the third comparator U2C.

6. The wide time delay power supply protection circuit based on PPTC resettable fuse according to claim 1, characterized in that: The execution protection module includes a transistor Q2, a diode D1, a diode D2 and a load. The base of the transistor Q2 is connected to the load, the collector is connected to the node of the transient suppression diode D1 and the transient suppression diode D2, and the emitter is grounded. The transient suppression diode D1 and the transient suppression diode D2 are respectively connected to the threshold analysis module.

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