Power-off automatic protection circuit

Abstract

The utility model relates to a power-off automatic protection circuit which comprises an L line end, an N line end, a master control circuit and a protection circuit which are connected in series to form a loop. According to the main control circuit, an L line end is respectively connected with a first end of a second bridge rectifier and a protection circuit through a fuse; the second end of the second bridge rectifier is connected with the first electrolytic capacitor, the fifteenth resistor and the first end of the transformer, the third end of the second bridge rectifier is connected with the N line end, and the fourth end of the second bridge rectifier is grounded; the other end of the first electrolytic capacitor is grounded; the other end of the fifteenth resistor is connected with the second capacitor and the VCC end of the main chip. The other end of the second capacitor and the GND end of the main chip are grounded; the DRV end of the main chip is connected with the grid electrode of the MOS tube through a nineteenth resistor, and the Isen end of the main chip is grounded through a ninth resistor and a fourteenth resistor; the drain electrode of the MOS tube is connected with the third end of the transformer, and the source electrode of the MOS tube is grounded through a fourteenth resistor. According to the power-off change of the input voltage, a response is quickly made, and the power supply circuit is automatically protected.

Description

TECHNICAL FIELD

[0001] The utility model relates to a power-off automatic protection circuit. BACKGROUND

[0002] With the development of the times and the continuous progress of science and technology, LED lighting lamps and lanterns will be more and more popular, at present, many LED lighting lamps and lanterns on the market cannot turn off LED in time after power failure, most of them have the phenomenon of lamp off back flashing, especially the high-voltage output lamps and lanterns, not only poor experience, but also affect the service life of LED.

[0003] Therefore, a power-off automatic protection circuit is provided. UTILITY MODEL CONTENTS

[0004] The utility model discloses a power-off automatic protection circuit which overcomes the defects of the prior art, optimizes the performance of the power supply of the LED lamp, improves the service life of the LED lamp, and quickly responds to the power failure of the input voltage to automatically protect the power supply circuit.

[0005] The technical scheme for achieving the above-mentioned purpose is as follows:

[0006] A power-off automatic protection circuit, comprising: an L line end, an N line end, a main control circuit and a protection circuit, the L line end, the N line end, the main control circuit and the protection circuit being connected in series to form a loop;

[0007] The main control circuit comprises: a fuse,

[0008] The L line end is connected to the 1 end of a second bridge stack and the protection circuit through the fuse respectively;

[0009] The 2 end of the second bridge stack is connected to a first electrolytic capacitor, a fifteenth resistor and a 1 end of a transformer respectively, the 3 end of the second bridge stack is connected to the N line end, and the 4 end of the second bridge stack is grounded;

[0010] The other end of the first electrolytic capacitor is grounded;

[0011] The other end of the fifteenth resistor is connected to a second capacitor and a VCC end of a main chip respectively;

[0012] The other end of the second capacitor and a GND end of the main chip are grounded;

[0013] The DRV end of the main chip is connected to the gate of a MOS tube through a nineteenth resistor, and the Isen end of the main chip is grounded through a ninth resistor and a fourteenth resistor;

[0014] The drain of the MOS tube is connected to the 3 end of the transformer, and the source of the MOS tube is grounded through the fourteenth resistor;

[0015] The 4th end of the transformer is connected to the anode of a second diode, the cathode of the second diode is connected to one end of a second electrolytic capacitor, the other end of the second electrolytic capacitor is connected to the 5th end of the transformer, and the two ends of the second electrolytic capacitor are connected in parallel with an LED;

[0016] The protection circuit comprises a first bridge stack,

[0017] The fuse is connected to the 1st end of the first bridge stack through a fourth resistor, the 2nd end of the first bridge stack is connected to the cathode of a voltage stabilizing diode, a second resistor and a third resistor through a first resistor respectively, the 3rd end of the first bridge stack is connected to the N terminal through a fifth resistor, and the 4th end of the first bridge stack is grounded.

[0018] The anode of the voltage stabilizing diode and the other end of the second resistor are grounded.

[0019] The other end of the third resistor is connected to a first capacitor and the base of a triode respectively, the emitter of the triode is connected to the VCC terminal of the main chip, and the collector of the triode is grounded.

[0020] Preferably, when the L terminal and the N terminal are connected to an input voltage, a loop is formed by the fuse, the second bridge stack, the transformer, the MOS tube and the fourteenth resistor and is finally grounded.

[0021] Preferably, the main chip is used to output control the opening and closing of the MOS tube.

[0022] Preferably, when the L terminal and the N terminal are connected to an input voltage, the first bridge stack outputs, and the voltage stabilizing diode clamps the voltage at a fixed voltage V1; when the fixed voltage V1 is higher than the supply voltage Vcc of the main chip, the triode cannot be turned on, the supply voltage Vcc is clamped at a required fixed value through the fifteenth resistor and the internal part of the main chip, and the main chip works normally.

[0023] Preferably, when the L terminal and the N terminal are powered off, the first electrolytic capacitor is used to maintain the normal work of the main chip, the voltage stabilizing diode clamps the voltage at a fixed voltage V1 which starts to drop, when the fixed voltage V1 is lower than the supply voltage Vcc of the main chip, the triode is turned on, the voltage of the VCC terminal of the main chip is pulled down to ground, so that the main chip stops working, and at this time, the MOS tube is in a closed state.

[0024] The utility model discloses a beneficial effect is: the utility model circuit is simple, and the cost is less, and the use range is wide, can be applied to the power-off protection of most power supply, and the circuit is different from the power-off protection device circuit of ordinary, and it lies in the internal detection input voltage signal, and the work of control power supply internal chip is controlled, and the power-off automatic protection circuit is through the small signal change of control unit circuit to cut off the power supply voltage of main loop chip, thereby realizing the working condition of protecting whole power supply. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a schematic diagram of the utility model one kind power-off automatic protection circuit. DETAILED DESCRIPTION

[0026] The technical scheme of the utility model will be described clearly and completely in combination with the drawings. In the description of the utility model, it is explained that the orientation or position relation of the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is based on the orientation or position relation shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as the restriction of the utility model. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying the importance of the opposite.

[0027] The utility model will be further described in combination with the drawings.

[0028] As Figure 1 Shown, a kind of power-off automatic protection circuit, it is characterized in that, including: L line end, N line end, main control circuit and protection circuit, L line end, N line end, main control circuit and protection circuit are connected in series into loop;

[0029] Main control circuit includes: fuse F1,

[0030] L line end is connected with the 1 end of second bridge stack BR2 and protection circuit respectively by fuse F1;

[0031] The 2 end of second bridge stack BR2 is connected with first electrolytic capacitor EC1, fifteenth resistance R15 and transformer T1 respectively, the 3 end of second bridge stack BR2 is connected with N line end, and the 4 end of second bridge stack BR2 is grounded;

[0032] The other end of first electrolytic capacitor EC1 is grounded;

[0033] The other end of fifteenth resistance R15 is connected with second capacitor C2 and the VCC end of main chip U1 respectively;

[0034] The other end of second capacitor C2 and the GND end of main chip U1 are grounded;

[0035] The DRV end of the main chip U1 is connected to the gate of the MOS tube Q2 through the nineteenth resistor R19, and the Isen end of the main chip U1 is grounded through the ninth resistor R9 and the fourteenth resistor R14.

[0036] The drain of the MOS tube Q2 is connected to the 3 end of the transformer T1, and the source of the MOS tube Q2 is grounded through the fourteenth resistor R14.

[0037] The 4 end of the transformer T1 is connected to the anode of the second diode D2, the cathode of the second diode D2 is connected to one end of the second electrolytic capacitor EC2, the other end of the second electrolytic capacitor EC2 is connected to the 5 end of the transformer T1, and the LED is connected in parallel across the two ends of the second electrolytic capacitor EC2.

[0038] The protection circuit comprises a first bridge stack BR1,

[0039] The fuse F1 is connected to the 1 end of the first bridge stack BR1 through the fourth resistor R4, the 2 end of the first bridge stack BR1 is respectively connected to the cathode of the voltage stabilizing diode ZD1, the second resistor R2 and the third resistor R3 through the first resistor R1, the 3 end of the first bridge stack BR1 is connected to the N line end through the fifth resistor R5, and the 4 end of the first bridge stack BR1 is grounded.

[0040] The anode of the voltage stabilizing diode ZD1 and the other end of the second resistor R2 are grounded.

[0041] The other end of the third resistor R3 is respectively connected to the first capacitor C1 and the base of the triode Q1, the emitter of the triode Q1 is connected to the VCC end of the main chip U1, and the collector of the triode Q1 is grounded.

[0042] In the embodiment, when the L line end and the N line end are connected to the input voltage, a loop is formed by the fuse F1, the second bridge stack BR2, the transformer T1, the MOS tube Q2 and the fourteenth resistor R14, and finally grounded.

[0043] In the embodiment, the main chip U1 is used to output control the opening and closing of the MOS tube Q2, and realize the energy and transmission of the transformer T1.

[0044] Working principle:

[0045] When the L line end and the N line end are connected to the input voltage, the first bridge stack BR1 outputs, and the voltage stabilizing diode ZD1 clamps the voltage at a fixed voltage V1; when the fixed voltage V1 is higher than the supply voltage Vcc of the main chip U1, the triode Q1 cannot be turned on, the supply voltage Vcc is clamped at a required fixed value through the fifteenth resistor R15 and the internal of the main chip U1, and the main chip U1 works normally.

[0046] When the L line end and the N line end are powered off, the first electrolytic capacitor EC1 maintains the main chip U1 to work normally, and does not cut off the energy transmission from the transformer T1 to the rear end in time, but due to the power-off, the voltage of the voltage stabilizing diode ZD1 is clamped at a fixed voltage V1 and starts to drop, when the fixed voltage V1 is lower than the supply voltage Vcc of the main chip U1, the triode Q1 is turned on, and the voltage at the VCC end of the main chip U1 is pulled down to the ground, so that the main chip U1 stops working rapidly, at this time, the MOS tube Q2 is also in the closed state, and the transformer T1 has no current change of the switch and cannot transmit energy to the rear end, thereby realizing the automatic protection of the circuit.

[0047] The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A power-off automatic protection circuit, characterized by comprising: The utility model relates to a kind of voltage stabilizer, including: L line end, N line end, main control circuit and protection circuit, the L line end, N line end, main control circuit and protection circuit are connected in series into loop; The main control circuit includes: fuse (F1), The L line end is connected respectively by the fuse (F1) 1 end of second bridge stack (BR2) and the protection circuit; The 2 end of the second bridge stack (BR2) is connected respectively first electrolytic capacitor (EC1), fifteenth resistance (R15) and transformer (T1) 1 end, the 3 end of the second bridge stack (BR2) is connected the N line end, the 4 end of the second bridge stack (BR2) is grounded; The other end of the first electrolytic capacitor (EC1) is grounded; The other end of the fifteenth resistance (R15) is connected respectively second capacitor (C2) and main chip (U1) VCC end; The other end of the second capacitor (C2) and the GND end of the main chip (U1) are grounded; The DRV end of the main chip (U1) is connected the gate of MOS transistor (Q2) by nineteenth resistance (R19), and the Isen end of the main chip (U1) is grounded by ninth resistance (R9) and fourteenth resistance (R14); The drain of the MOS transistor (Q2) is connected the 3 end of the transformer (T1), and the source of the MOS transistor (Q2) is grounded by the fourteenth resistance (R14); The 4 end of the transformer (T1) is connected the anode of the second diode (D2), and the cathode of the second diode (D2) is connected one end of second electrolytic capacitor (EC2), and the other end of the second electrolytic capacitor (EC2) is connected the 5 end of the transformer (T1), and the LED is connected in parallel across the second electrolytic capacitor (EC2); The protection circuit includes: first bridge stack (BR1), The fuse (F1) is connected the 1 end of the first bridge stack (BR1) by fourth resistance (R4), and the 2 end of the first bridge stack (BR1) is connected respectively the cathode of stabilizing diode (ZD1), second resistance (R2) and third resistance (R3) by first resistance (R1), and the 3 end of the first bridge stack (BR1) is connected the N line end by fifth resistance (R5), and the 4 end of the first bridge stack (BR1) is grounded; The anode of the stabilizing diode (ZD1) and the other end of second resistance (R2) are grounded; The other end of the third resistance (R3) is connected respectively first capacitor (C1) and the base of triode (Q1), and the emitter of the triode (Q1) is connected the VCC end of the main chip (U1), and the collector of the triode (Q1) is grounded.

2. The automatic protection circuit according to claim 1, wherein When the L line end, N line end are connected input voltage, form loop finally by the fuse (F1), second bridge stack (BR2), transformer (T1), MOS transistor (Q2) and fourteenth resistance (R14) and ground.

3. The automatic protection circuit according to claim 1, wherein The main chip (U1) is used for output control the opening and closing of the MOS transistor (Q2).

4. The automatic protection circuit according to claim 1, wherein When the L terminal, N terminal connects the input voltage, the first bridge stack (BR1) output, the voltage regulator diode (ZD1) will be clamped at a fixed voltage V1; when the fixed voltage V1 is higher than the main chip (U1) supply voltage Vcc, the transistor (Q1) can not be turned on, the supply voltage Vcc through the fifteenth resistance (R15) and the main chip (U1) internal clamping at a required fixed value, maintain the normal work of the main chip (U1).

5. The automatic protection circuit according to claim 1, wherein When the L terminal, N terminal power off, through the first electrolytic capacitor (EC1) to maintain the normal work of the main chip (U1), the voltage regulator diode (ZD1) will be clamped at a fixed voltage V1 begins to decline, when the fixed voltage V1 is lower than the main chip (U1) supply voltage Vcc, the transistor (Q1) is turned on, pull down the voltage of the VCC end of the main chip (U1) to ground, so that the main chip (U1) stop working, at this time, the MOS tube (Q2) is in the closed state.

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