A control device for power-on delay, power-off and fast shutdown based on capacitor characteristics

Abstract

The present invention discloses a control device for power-on delay and power-off fast shutdown based on capacitor characteristics, comprising a main power supply, an overcurrent protection circuit, a switch circuit, a main capacitor, a charge-discharge circuit for charging or discharging the main capacitor, a switch drive circuit for controlling the switch circuit to be in one of an on and off state according to a voltage signal of the main capacitor, and an output circuit for outputting a pure voltage, wherein the output end of the main power supply is connected to the input end of the overcurrent protection circuit, the switch circuit, the charge-discharge circuit, the switch drive circuit and the output circuit are all connected to the output end of the overcurrent protection circuit, and the switch drive circuit is connected to the charge-discharge circuit via the main capacitor; in the present invention, a controlled delay time is obtained by controlling the time for the charge-discharge circuit to charge and discharge the main capacitor to open the control switch of the main circuit, thereby realizing the delay of the output power supply of the main circuit; when the power is off, the main capacitor is quickly short-circuited and discharged to realize the fast shutdown of the output power supply of the main circuit.

Description

Technical Field

[0001] The invention relates to the field of electronic circuits, and in particular to a control device for power-on delay and power-off fast shutdown based on capacitance characteristics. Background Art

[0002] At present, the control application of power-on delay start and power-off fast shutdown of power supply is very extensive in the field of electronic circuits. In the existing technology, delay control is generally achieved through delay relays, delay switches or single-chip delay. However, these solutions have the problems of high cost and untimely fast shutdown. At the same time, the application range of this type of general delay and fast-break control device is quite wide. How to design and produce a low-cost and fast-shutdown device has become a technical problem that urgently needs to be solved in this field. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a control device for power-on delay and power-off fast shutdown based on capacitor characteristics, which can solve the problems of high production cost and untimely fast shutdown of traditional delay and fast-break control devices.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A control device for power-on delay and power-off fast shutdown based on capacitor characteristics, comprising a main power supply for external connection to an external power supply, an overcurrent protection circuit for overcurrent protection of the main power supply, a switch circuit for controlling the main power supply to be in one of the on and off states, a main capacitor, a charge and discharge circuit for charging or discharging the main capacitor, a switch drive circuit for controlling the switch circuit to be in one of the on and off states according to a voltage signal of the main capacitor, and an output circuit for outputting a pure voltage, wherein the output end of the main power supply is connected to the input end of the overcurrent protection circuit, the switch circuit, the charge and discharge circuit, the switch drive circuit and the output circuit are all connected to the output end of the overcurrent protection circuit, and the switch drive circuit is connected to the charge and discharge circuit via the main capacitor.

[0006] Preferably, the main power supply includes an inductor L1, a polarized capacitor C2 and a capacitor C3, the input end of the overcurrent protection circuit, the positive electrode of the polarized capacitor C2 and one end of the capacitor C3 are all connected to one end of the inductor L1, the other end of the inductor L1 is connected to an external power supply, and the negative electrode of the polarized capacitor C2 and the other end of the capacitor C3 are both grounded.

[0007] Preferably, the overcurrent protection circuit includes a fuse F1 and a capacitor C4, one end of the fuse F1 and one end of the capacitor C4 are connected to the output end of the main power supply, and the other end of the capacitor C4, the input end of the switching circuit and the input end of the charging and discharging circuit are all connected to the other end of the fuse F1.

[0008] Preferably, the fuse F1 is a resettable fuse F1.

[0009] Preferably, the charging and discharging circuit includes a resistor R3, a resistor R6, a diode D1 and a diode D2, the output end of the overcurrent protection circuit, the cathode of the diode D1, the cathode of the diode D2 and the switching circuit are all connected to one end of the resistor R3, the anode of the diode D1, the anode of the diode D2, one end of the resistor R6 and the main capacitor are all connected to the other end of the resistor R3, and the other end of the resistor R6 is grounded.

[0010] Preferably, the main capacitor includes a polar capacitor C1, the positive electrode of the diode D1, the positive electrode of the diode D2, one end of the resistor R6, the other end of the resistor R3 and the switch drive circuit are all connected to the positive electrode of the polar capacitor C1, and the negative electrode of the polar capacitor C1 is grounded.

[0011] Preferably, the switch driving circuit includes a transistor Q2, a transistor Q3, a resistor R2, a resistor R7 and a voltage-stabilizing diode DZ1; the output end of the overcurrent protection circuit and the switch circuit are both connected to one end of the resistor R2; the other end of the resistor R2 is connected to the collector of the transistor Q2; the base of the transistor Q2 is connected to the main capacitor; one end of the resistor R7 and the negative electrode of the voltage-stabilizing diode DZ1 are both connected to the emitter of the transistor Q2; the positive electrode of the voltage-stabilizing diode DZ1 is connected to the base of the transistor Q3; the collector of the transistor Q3 is connected to the switch circuit; the emitter of the transistor Q3 and the other end of the resistor R7 are grounded.

[0012] Preferably, the switching circuit includes a resistor R4, a resistor R5 and a field effect transistor Q1, one end of the resistor R4, the output end of the overcurrent protection circuit and the switch drive circuit are all connected to the drain of the field effect transistor Q1, the other end of the resistor R4 and one end of the resistor R5 are both connected to the gate of the field effect transistor Q1, the source of the field effect transistor Q1 is connected to the output circuit, and the other end of the resistor R5 is connected to the switch drive circuit.

[0013] Preferably, the output circuit includes a polarized capacitor C5 and a capacitor C6, the positive electrode of the polarized capacitor C5 and one end of the capacitor C6 are both connected to the switch circuit, and the negative electrode of the polarized capacitor C5 and the other end of the capacitor C6 are both grounded.

[0014] Compared with the prior art, the beneficial effects of the present invention are: by controlling the time of charging and discharging the main capacitor by the charging and discharging circuit, a controlled delay time is obtained to open the control switch of the main circuit, thereby realizing the delay of the output power of the main circuit; when the power is off, the main capacitor is quickly short-circuited and discharged to realize the rapid shutdown of the output power of the main circuit. At the same time, the main delay and discharge devices in the present invention are ordinary capacitors and diodes, the control part is composed of passive resistors, capacitors and triodes, and the control switch adopts ordinary low-speed field effect tubes. Furthermore, different field effect tubes can be flexibly selected according to the load power controlled, wherein the main passive devices of the circuit ensure the stability of the work, and conventional materials and optional control switches can meet the needs while saving costs to the maximum extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the control device for power-on delay and power-off fast shutdown based on capacitor characteristics described in the present invention.

[0016] Figure 2 The present invention is a circuit diagram of a control device for power-on delay, power-off and fast shutdown based on capacitance characteristics described in the present invention.

[0017] Figure 3 It is a circuit diagram of the main power supply described in the present invention.

[0018] Figure 4 is a circuit diagram of the overcurrent protection circuit described in the present invention.

[0019] Figure 5 It is a circuit diagram of the charging and discharging circuit and the main capacitor described in the present invention.

[0020] Figure 6 4 is a circuit diagram of the switch driving circuit described in the present invention.

[0021] Figure 7 is a circuit diagram of the switch circuit described in the present invention.

[0022] Figure 8 is a circuit diagram of the output circuit described in the present invention. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0024] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] Below, the present invention is further described in conjunction with the accompanying drawings and specific embodiments:

[0027] In the present invention, the resettable fuse is an overcurrent electronic protection element, which is made of high molecular organic polymer under high pressure, high temperature, and vulcanization reaction conditions, mixed with conductive particle materials, and processed by special technology. Traditional fuse overcurrent protection can only protect once, and needs to be replaced if it burns out, while the resettable fuse has the dual functions of overcurrent and overheat protection and automatic recovery. The polar capacitor is a capacitor of the type of electrolytic capacitor, which is composed of two electrodes formed by the aluminum foil of the anode and the electrolyte of the cathode, and cannot be connected incorrectly, and a layer of aluminum oxide film produced on the anode aluminum foil is used as the dielectric capacitor.

[0028] like Figure 1-8 As shown, a control device for power-on delay and power-off fast shutdown based on capacitor characteristics includes a main power supply for externally connecting to an external power supply, an overcurrent protection circuit for overcurrent protection of the main power supply, a switch circuit for controlling the main power supply to be in one of an on and off state, a main capacitor, a charge and discharge circuit for charging or discharging the main capacitor, a switch drive circuit for controlling the switch circuit to be in one of an on and off state according to a voltage signal of the main capacitor, and an output circuit for outputting a pure voltage, wherein the output end of the main power supply is connected to the input end of the overcurrent protection circuit, the switch circuit, the charge and discharge circuit, the switch drive circuit and the output circuit are all connected to the output end of the overcurrent protection circuit, and the switch drive circuit is connected to the charge and discharge circuit through the main capacitor.

[0029] Specifically, the main power supply includes an inductor L1, a polarized capacitor C2 and a capacitor C3, the overcurrent protection circuit includes a fuse F1 and a capacitor C4, preferably, the fuse F1 is a self-recovering fuse F1, the charging and discharging circuit includes a resistor R3, a resistor R6, a diode D1 and a diode D2, the main capacitor includes a polarized capacitor C1, the switch drive circuit includes a transistor Q2, a transistor Q3, a resistor R2, a resistor R7 and a voltage-stabilizing diode DZ1, the switch circuit includes a resistor R4, a resistor R5 and a field effect transistor Q1, and the output circuit includes a polarized capacitor C5 and a capacitor C6. In this embodiment, if Figure 4 As shown, one end of the resettable fuse F1, one end of the capacitor C4, the positive electrode of the polar capacitor C2 and one end of the capacitor C3 are all connected to one end of the inductor L1, and the other end of the inductor L1 is connected to the external power supply. The other end of the resettable fuse F1, the other end of the capacitor C4, the negative electrode of the diode D1, the negative electrode of the diode D2, one end of the resistor R3, one end of the resistor R2 and one end of the resistor R4 are all connected to the drain of the field effect transistor Q1. The positive electrode of the diode D1, the positive electrode of the diode D2, the base of the transistor Q2, one end of the resistor R6 and the positive electrode of the polar capacitor C1 are all connected to the other end of the resistor R3. The collector of the polar capacitor C2 is connected to the other end of the resistor R2, one end of the resistor R7 and the cathode of the voltage-stabilizing diode DZ1 are both connected to the emitter of the transistor Q2, the other end of the resistor R4 and one end of the resistor R5 are both connected to the gate of the field effect transistor Q1, the other end of the resistor R5 is connected to the collector of the transistor Q3, the positive electrode of the polar capacitor C5 and one end of the capacitor C6 are both connected to the source of the field effect transistor Q1, the cathode of the polar capacitor C2, the other end of the capacitor C3, the other end of the resistor R6, the cathode of the polar capacitor C1, the other end of the resistor R7, the emitter of the transistor Q3, the cathode of the polar capacitor C5 and the other end of the capacitor C6 are all grounded.

[0030] In this embodiment, a DC voltage of 3-100V is input into the main power supply through an external power supply, and an LC filter is formed by inductor L1, capacitor C2, and capacitor C3 to filter and purify the input power supply, and then the current flowing through the main power supply is limited by an overcurrent protection circuit composed of a self-recovery fuse F1 and capacitor C4, wherein capacitor C4 plays a role in pulse suppression. When the current enters the charge and discharge circuit, resistors R3 and R6 first divide the voltage input by the main power supply, and then charge the polar capacitor C1. At the same time, resistor R3 plays a role in charging current limiting, so resistor R3 determines the time required for capacitor C1 to be fully charged, and the charging time can be adjusted by adjusting the value of resistor R3, so resistor R3 can be set as an adjustable resistor or a sliding rheostat to achieve the adjustment of the charging time. In this embodiment, the polar capacitor C1 is the main capacitor for charging delay. The value of the polar capacitor C1 will also affect the charging time, so the polar capacitor C1 is generally 220uF. Further, the diode D1 and the diode D2 form a discharge circuit of the main capacitor. In the power-on stage, the positive electrode voltage of the diode D1 and the diode D2 is lower than the negative electrode voltage, so the diode D1 and the diode D2 are not turned on. In the power-off stage, the positive electrode voltage of the diode D1 and the diode D2 is higher than the negative electrode voltage, and the diode D1 and the diode D2 are turned on, causing the polar capacitor C1 to discharge to the main power supply, so that the voltage of the polar capacitor C1 is rapidly reduced, and the main capacitor is quickly discharged. In this embodiment, the diode D1 and the diode D2 are connected in parallel to minimize the impedance of the discharge circuit and the heat generated by the diode during discharge (discharging the polar capacitor C1 can not only quickly shut down the main power supply, but also ensure that there is no residual electricity in the main capacitor when the circuit is powered on next time, which will not affect the delay time of the circuit); preferably, the resistor R2, the resistor R7, the resistor R4, the resistor R5, the transistor Q2, the transistor Q3, and the diode DZ1 form a switch drive circuit and a switch circuit, which are used to drive the main power supply to be in one of the states of on and off,

[0031] When the voltage on the main capacitor is higher than 0.7V, the transistor Q2 is driven to conduct, so that the voltage on the resistor R7 rises to the point where the voltage-stabilizing diode DZ1 breaks down, and then the transistor Q3 is turned on. After the transistor Q3 is turned on, the collector voltage changes from high voltage to low voltage, thereby pulling down the gate voltage of the field effect transistor Q1 of the switch circuit. The field effect transistor Q1 is turned on to turn on the main power supply voltage for output. When the main power input voltage is powered off and the voltage drops, the cathode voltage of the diode D1 and the diode D2 is lower than the positive voltage, and the diode D1 and the diode D2 begin to conduct. The conducted diodes D1 and D2 supply power to the voltage stored on the main capacitor, causing the voltage of the polar capacitor C1 to drop rapidly. When the voltage of the polar capacitor C1 drops below 0.7V, the transistor Q2 is turned off, and the transistor Q3 is also turned off. The gate voltage of the field effect transistor Q1 is pulled up, the field effect transistor Q1 is turned off, and the main power output is turned off. The entire circuit achieves delayed output of the main power supply by slowly charging the main capacitor, and quickly shuts off the main power supply by quickly discharging the polarized capacitor C1. The polarized capacitors C5 and C6 are decoupling capacitors for the output voltage, which can ensure the purity of the output voltage.

[0032] The working process of this embodiment is as follows: when the main power supply is powered on, the output circuit has no voltage output due to the non-conduction of the field effect tube Q1. The resistor R3 and the resistor R6 take power from the main power supply after filtering and overcurrent protection to charge the main capacitor (polar capacitor C1). When the voltage on the main capacitor slowly rises to a high voltage value, the control driving circuit drives the field effect tube Q1 to conduct, and only then does the output circuit have voltage output; when the main power supply is powered off, due to the presence of inductance and capacitance in the circuit, the output voltage will not disappear immediately, but the voltage of the main capacitor is lower than 0.7V after being quickly discharged. This extremely low voltage can no longer control the field effect tube Q1 in the switch circuit to conduct, causing the field effect tube Q1 to be quickly cut off, and the output circuit voltage is turned off, which is also ready for the next circuit power-on.

[0033] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A control device for power-on delay and power-off fast shutdown based on capacitor characteristics, characterized in that: It includes a main power supply for connecting to an external power supply, an overcurrent protection circuit for protecting the main power supply from overcurrent, a switch circuit for controlling the main power supply to be in one of the on and off states, a main capacitor, a charge and discharge circuit for charging or discharging the main capacitor, a switch drive circuit for controlling the switch circuit to be in one of the on and off states according to a voltage signal of the main capacitor, and an output circuit for outputting a pure voltage. The output end of the main power supply is connected to the input end of the overcurrent protection circuit, the switch circuit, the charge and discharge circuit, the switch drive circuit and the output circuit are all connected to the output end of the overcurrent protection circuit, and the switch drive circuit is connected to the charge and discharge circuit via the main capacitor. The main power supply includes an inductor L1, a polarized capacitor C2 and a capacitor C3. The input end of the overcurrent protection circuit, the positive electrode of the polarized capacitor C2 and one end of the capacitor C3 are all connected to one end of the inductor L1. The other end of the inductor L1 is connected to an external power supply. The negative electrode of the polarized capacitor C2 and the other end of the capacitor C3 are all grounded. The charging and discharging circuit includes a resistor R3, a resistor R6, a diode D1 and a diode D2. The output end of the overcurrent protection circuit, the cathode of the diode D1, the cathode of the diode D2 and the switching circuit are all connected to one end of the resistor R3. The anode of the diode D1, the anode of the diode D2, one end of the resistor R6 and the main capacitor are all connected to the other end of the resistor R3. The other end of the resistor R6 is grounded.

2. The control device for power-on delay and power-off fast shutdown based on capacitance characteristics according to claim 1, characterized in that: The overcurrent protection circuit includes a fuse F1 and a capacitor C4, one end of the fuse F1 and one end of the capacitor C4 are connected to the output end of the main power supply, and the other end of the capacitor C4, the input end of the switch circuit and the input end of the charge and discharge circuit are all connected to the other end of the fuse F1.

3. The control device for power-on delay and power-off fast shutdown based on capacitance characteristics as claimed in claim 2, characterized in that: The fuse F1 is a resettable fuse F1.

4. The control device for power-on delay and power-off fast shutdown based on capacitance characteristics according to claim 1, characterized in that: The main capacitor includes a polar capacitor C1, the anode of the diode D1, the anode of the diode D2, one end of the resistor R6, the other end of the resistor R3 and the switch drive circuit are all connected to the anode of the polar capacitor C1, and the cathode of the polar capacitor C1 is grounded.

5. The control device for power-on delay and power-off fast shutdown based on capacitance characteristics according to claim 1, characterized in that: The switch drive circuit includes a transistor Q2, a transistor Q3, a resistor R2, a resistor R7 and a voltage-stabilizing diode DZ1. The output end of the overcurrent protection circuit and the switch circuit are both connected to one end of the resistor R2, the other end of the resistor R2 is connected to the collector of the transistor Q2, the base of the transistor Q2 is connected to the main capacitor, one end of the resistor R7 and the negative electrode of the voltage-stabilizing diode DZ1 are both connected to the emitter of the transistor Q2, the positive electrode of the voltage-stabilizing diode DZ1 is connected to the base of the transistor Q3, the collector of the transistor Q3 is connected to the switch circuit, and the emitter of the transistor Q3 and the other end of the resistor R7 are grounded.

6. The control device for power-on delay and power-off fast shutdown based on capacitance characteristics according to claim 1, characterized in that: The switch circuit includes a resistor R4, a resistor R5 and a field effect transistor Q1, one end of the resistor R4, the output end of the overcurrent protection circuit and the switch drive circuit are all connected to the drain of the field effect transistor Q1, the other end of the resistor R4 and one end of the resistor R5 are both connected to the gate of the field effect transistor Q1, the source of the field effect transistor Q1 is connected to the output circuit, and the other end of the resistor R5 is connected to the switch drive circuit.

7. The control device for power-on delay and power-off fast shutdown based on capacitance characteristics according to claim 1, characterized in that: The output circuit includes a polar capacitor C5 and a capacitor C6, wherein the positive electrode of the polar capacitor C5 and one end of the capacitor C6 are both connected to the switch circuit, and the negative electrode of the polar capacitor C5 and the other end of the capacitor C6 are both grounded.

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