A nuclear radiation resistant LED driver circuit

Abstract

The present invention relates to a nuclear radiation-resistant LED driver circuit, which is connected to an LED lamp bead and includes a power input terminal, an over-temperature protection circuit, a rectifier circuit, a constant current circuit, a filter circuit and a short-circuit protection circuit. The power input terminal, the over-temperature protection circuit, the rectifier circuit, the constant current circuit and the LED lamp bead are connected in sequence, and the filter circuit and the short-circuit protection circuit are respectively connected to the constant current circuit. Compared with the prior art, the present invention has the advantages of inputting a high PF value, having a short-circuit protection function, and the power can be expanded to a high power.

Description

Technical Field

[0001] The invention relates to an LED driver circuit, in particular to an LED driver circuit resistant to nuclear radiation. Background Art

[0002] At present, the energy gap is getting bigger and bigger, and the use of nuclear energy is widely accepted, but the lighting equipment in nuclear power plants must be resistant to nuclear radiation, and the market still basically uses traditional inductive ballasts. As the high efficiency, energy saving and fast response characteristics of LED green lighting become more and more prominent, it has not been used in nuclear power plants. The driver is the biggest bottleneck, because a large number of logic circuits are used in the driver, and the radiation resistance is very low.

[0003] After searching, Chinese patent publication number CN112867197A discloses a radiation-resistant LED lamp, which specifically includes a radiation-resistant LED light source and a radiation-resistant LED driver, wherein the radiation-resistant LED driver includes a circuit substrate, and the control circuit of the LED light source board adopts a four-terminal constant current source circuit, and the constant current diode of the majority current device is used as a reference. Another advantage of the constant current diode is that it is little affected by nuclear radiation. The AC power supply 220V is converted into AC low voltage by transformer T through the EMC filter L1, and becomes a DC voltage through capacitor C2 after rectification by the rectifier bridge stack. However, the driver uses 1-3CM lead plate for shielding, which causes high cost and is very bulky. At the same time, there are problems such as poor radiation resistance, no over-temperature protection and short-circuit protection functions. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a nuclear radiation-resistant LED driver circuit with a high input PF value, a short-circuit protection function, and power that can be expanded to high power.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] According to one aspect of the present invention, a nuclear radiation-resistant LED driver circuit is provided, which is connected to an LED lamp bead and includes a power input terminal, an over-temperature protection circuit, a rectifier circuit, a constant current circuit, a filter circuit and a short-circuit protection circuit. The power input terminal, the over-temperature protection circuit, the rectifier circuit, the constant current circuit and the LED lamp bead are connected in sequence, and the filter circuit and the short-circuit protection circuit are respectively connected to the constant current circuit.

[0007] As a preferred technical solution, the power input end is a three-phase input AC power L1, L2, L3, and the three-phase input AC power is rectified by a rectifier circuit to become a low-ripple DC voltage.

[0008] As a preferred technical solution, the over-temperature protection circuit is a temperature switch TH1, which is connected to one phase of the three-phase input AC power and is used to cut off one phase of the three-phase input AC power and convert it into a two-phase input.

[0009] As a preferred technical solution, the rectifier circuit includes rectifier diodes D1, D2, D3, D4, D5 and D6, wherein the positive electrode of the rectifier diode D1 is respectively connected to L1 and the negative electrode of the rectifier diode D2, the positive electrode of the rectifier diode D3 is respectively connected to L2 and the negative electrode of the rectifier diode D4, the positive electrode of the rectifier diode D5 is respectively connected to L3 and the negative electrode of the rectifier diode D6, the positive electrode of the rectifier diode D2 is respectively connected to the positive electrode of the rectifier diode D4 and the positive electrode of the rectifier diode D6, and the negative electrode of the rectifier diode D1, the negative electrode of D3 and the negative electrode of D5 are respectively connected to the constant current circuit.

[0010] As a preferred technical solution, the constant current circuit includes a power adjustment tube Q1, a resistor R2, a current detection resistor R4 and a voltage regulator diode U1. The gate of the power adjustment tube Q1 is respectively connected to the positive electrode of the LED lamp bead and the negative electrode of the voltage regulator diode U1, the source of the power adjustment tube Q1 is respectively connected to one end of the resistor R2 and one end of the current detection resistor R4, the drain of the power adjustment tube Q1 is connected to the negative electrode of the LED lamp bead, the other end of the resistor R2 is connected to the input end of the voltage regulator diode U1, and the other end of the current detection resistor R4 is connected to the positive electrode of the voltage regulator diode U1.

[0011] As a preferred technical solution, the power adjustment tube Q1 is a silicon carbide MOS tube.

[0012] As a preferred technical solution, the constant current circuit further includes a resistor R1 disposed between the gate of the power adjustment tube Q1 and the positive electrode of the LED lamp bead.

[0013] As a preferred technical solution, the constant current circuit also includes a resistor R7 and a capacitor C1, one end of the resistor R7 is connected to the other end of the resistor R2, the other end of the resistor R7 is connected to the other end of the current detection resistor R4, and the capacitor C1 is connected between the input end and the negative electrode of the voltage regulator diode U1.

[0014] As a preferred technical solution, the filtering circuit includes a resistor R5 and a capacitor C2, one end of the resistor R5 is connected to the other end of the resistor R2, the other end of the resistor R5 is connected to one end of the capacitor C2, and the other end of the capacitor C2 is connected to the other end of the current detection resistor R4.

[0015] As a preferred technical solution, the short-circuit protection circuit includes a transistor Q2, a diode ZD1, a resistor R3 and a resistor R6, the collector of the transistor Q2 is connected to the source of the power adjustment tube Q1, the emitter of the transistor Q2 is connected to the other end of the current detection resistor R4, the base of the transistor Q2 is connected between one end of the resistor R3 and one end of the resistor R6, the other end of the resistor R3 is connected to the positive electrode of the diode ZD1, the negative electrode of the diode ZD1 is connected to the drain of the power adjustment tube Q1, and the other end of the resistor R6 is connected to the other end of the current detection resistor R4.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1) The present invention does not require any shielding components and can effectively resist radiation;

[0018] 2) The input of the present invention adopts three-phase input to achieve a high PF value.

[0019] 3) The present invention adopts linear average current control to achieve constant current, discrete components to achieve control, and strong radiation resistance;

[0020] 4) The present invention has multiple protections, including output short circuit quick protection and over-temperature protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A specific circuit diagram of the present invention;

[0022] Figure 2 It is the waveform diagram of the AC voltage of three-phase input;

[0023] Figure 3 This is the waveform of the pulsating DC after rectification. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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 embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0025] like Figure 1 As shown, a nuclear radiation-resistant LED driver circuit is connected to an LED lamp bead, including a power input terminal 1, an over-temperature protection circuit 2, a rectifier circuit 3, a constant current circuit 4, a filter circuit 5 and a short-circuit protection circuit 6. The power input terminal 1, the over-temperature protection circuit 2, the rectifier circuit 3, the constant current circuit 4 and the LED lamp bead are connected in sequence, and the filter circuit 5 and the short-circuit protection circuit 6 are respectively connected to the constant current circuit.

[0026] The power input end is a three-phase input AC power L1, L2, and L3, which is rectified by a rectifier circuit to become a low-ripple DC voltage. The rectifier circuit includes rectifier diodes D1, D2, D3, D4, D5, and D6, wherein the positive electrode of the rectifier diode D1 is connected to L1 and the negative electrode of the rectifier diode D2, respectively, the positive electrode of the rectifier diode D3 is connected to L2 and the negative electrode of the rectifier diode D4, respectively, the positive electrode of the rectifier diode D5 is connected to L3 and the negative electrode of the rectifier diode D6, the positive electrode of the rectifier diode D2 is connected to the positive electrode of the rectifier diode D4 and the positive electrode of the rectifier diode D6, and the negative electrode of the rectifier diode D1, the negative electrode of D3, and the negative electrode of D5 are connected to the constant current circuit, respectively.

[0027] Input L1, L2, L3, through the rectifier diodes D1, D2, D3, D4, D5 and D6, into a low ripple DC voltage. The specific waveform is as follows, Figure 2 is the three-phase input AC voltage, Figure 3 It is the pulsating DC voltage after full-bridge rectification. The three-phase input rectification can obtain a DC voltage with very small ripple, and the ripple frequency is 300HZ. The high-frequency ripple voltage supplies power to the LED lamp beads, and the human eye cannot feel the flicker, which is not easy to cause biological damage. At the same time, this input supplies linear power to the LED lamp beads, with small current distortion and high PF value.

[0028] The over-temperature protection circuit is a temperature switch TH1, which is connected to one phase of the three-phase input AC power and is used to cut off one phase of the three-phase input AC power and convert it into a two-phase input.

[0029] When the temperature of the driver is too high, the temperature switch TH1 will cut off the input of L1, thus becoming a two-phase input and reducing the output current by 1 / 3, but the average current will not change, and will not cause the Vf value of the LED light board to decrease, keeping the light effect unchanged. Since the scheme is based on a linear principle, after over-temperature protection, by controlling U1 to reduce the constant current of the light board, it is bound to cause the Vf of the light board to decrease, and the loss of the entire drive may not necessarily decrease, which fails to achieve the purpose of protecting the driver from high temperature.

[0030] The constant current circuit includes a power adjustment tube Q1, a resistor R2, a current detection resistor R4 and a voltage regulator diode U1. The gate of the power adjustment tube Q1 is connected to the positive electrode of the LED lamp bead and the negative electrode of the voltage regulator chip U1 respectively. The source of the power adjustment tube Q1 is connected to one end of the resistor R2 and one end of the current detection resistor R4. The drain of the power adjustment tube Q1 is connected to the negative electrode of the LED lamp bead. The other end of the resistor R2 is connected to the input end of the voltage regulator diode U1. The other end of the current detection resistor R4 is connected to the positive electrode of the voltage regulator chip U1. The constant current circuit also includes a resistor R1 arranged between the gate of the power adjustment tube Q1 and the positive electrode of the LED lamp bead. The constant current circuit also includes a resistor R7 and a capacitor C1. One end of the resistor R7 is connected to the other end of the resistor R2, and the other end of the resistor R7 is connected to the other end of the current detection resistor R4. The capacitor C1 is connected between the input end and the negative electrode of the voltage regulator diode U1.

[0031] When current flows through R4, voltage is generated, which is divided by R2 and R4 to the input detection terminal of U1. When the input terminal of U1 is higher than its internal reference, the voltage of its output 2 pin will be reduced, so that the driving voltage of the adjustment tube Q1 will be reduced, thereby increasing the on-resistance of Q1 and reducing the current passing through R4. In this way, the current of the LED lamp beads between LED+1 and LED-1 can be constant. In this circuit, Q1 uses silicon carbide MOS tubes, and ordinary MOS tubes cannot be used. After the irradiation test, the Vgs of ordinary MOS tubes drops greatly, resulting in failure to work normally. The Vgs of silicon carbide MOS tubes also drops slightly, but the circuit can output Vgs of 0 volts or even negative voltage, thus ensuring the normal operation of the constant current circuit. Q1 cannot use triodes either. The amplification factor of triodes drops geometrically after the irradiation test.

[0032] The filtering circuit includes a resistor R5 and a capacitor C2, one end of the resistor R5 is connected to the other end of the resistor R2, the other end of the resistor R5 is connected to one end of the capacitor C2, and the other end of the capacitor C2 is connected to the other end of the current detection resistor R4.

[0033] If the RC network is used without filtering, the constant current part uses peak limiting, which causes the LED lamp board voltage to be lower than the lowest ripple voltage after 3-phase rectification. If it is slightly higher, the current will drop, which will cause the LED lamp to have low light efficiency and serious heat generation. After filtering with R5 and C2, the average value is limited, so that the voltage drop between the lamp board voltage and the rectified voltage can be very small to achieve constant current, improving the light efficiency. At the same time, it can also increase the PF value.

[0034] The short-circuit protection circuit includes a transistor Q2, a diode ZD1, a resistor R3 and a resistor R6. The collector of the transistor Q2 is connected to the source of the power adjustment tube Q1, the emitter of the transistor Q2 is connected to the other end of the current detection resistor R4, the base of the transistor Q2 is connected between one end of the resistor R3 and one end of the resistor R6, the other end of the resistor R3 is connected to the positive electrode of the diode ZD1, the negative electrode of the diode ZD1 is connected to the drain of the power adjustment tube Q1, and the other end of the resistor R6 is connected to the other end of the current detection resistor R4.

[0035] When the lamp board is short-circuited or the input voltage exceeds the rated voltage, the drain voltage of Q1 exceeds the voltage set by ZD1, causing Q2 to turn on, thereby turning off Q1, thus effectively protecting Q1.

[0036] The present invention achieves radiation resistance through principles and devices. At the same time, it solves over-temperature protection and short-circuit protection. The total radiation dose is very high, reaching 100KGy in the test. At the same time, it can produce high power.

[0037] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A nuclear radiation resistant LED driver circuit, the circuit is connected to an LED lamp bead, characterized in that: It includes a power input terminal, an over-temperature protection circuit, a rectifier circuit, a constant current circuit, a filter circuit and a short-circuit protection circuit. The power input terminal, the over-temperature protection circuit, the rectifier circuit, the constant current circuit and the LED lamp beads are connected in sequence, and the filter circuit and the short-circuit protection circuit are respectively connected to the constant current circuit; The constant current circuit includes a power adjustment tube Q1, a resistor R2, a current detection resistor R4 and a voltage regulator diode U1. The gate of the power adjustment tube Q1 is connected to the positive electrode of the LED lamp bead and the negative electrode of the voltage regulator diode U1 respectively. The source of the power adjustment tube Q1 is connected to one end of the resistor R2 and one end of the current detection resistor R4. The drain of the power adjustment tube Q1 is connected to the negative electrode of the LED lamp bead. The other end of the resistor R2 is connected to the input end of the voltage regulator diode U1, and the other end of the current detection resistor R4 is connected to the positive electrode of the voltage regulator diode U1. The constant current circuit also includes a resistor R1 arranged between the gate of the power adjustment tube Q1 and the positive electrode of the LED lamp bead. The constant current circuit also includes a resistor R7 and a capacitor C1. One end of the resistor R7 is connected to the other end of the resistor R2, and the other end of the resistor R7 is connected to the other end of the current detection resistor R4. The capacitor C1 is connected between the input end and the negative electrode of the voltage regulator diode U1. The short-circuit protection circuit includes a transistor Q2, a diode ZD1, a resistor R3 and a resistor R6, the collector of the transistor Q2 is connected to the source of the power adjustment tube Q1, the emitter of the transistor Q2 is connected to the other end of the current detection resistor R4, the base of the transistor Q2 is connected between one end of the resistor R3 and one end of the resistor R6, the other end of the resistor R3 is connected to the positive electrode of the diode ZD1, the negative electrode of the diode ZD1 is connected to the drain of the power adjustment tube Q1, and the other end of the resistor R6 is connected to the other end of the current detection resistor R4; The power adjustment tube Q1 is a silicon carbide MOS tube; when current flows through R4, a voltage is generated, and the voltage is divided by R2 and R4 to the input detection end of U1. When the input end of U1 is higher than its internal reference, the voltage of its output 2 pin will be reduced, so that the driving voltage of the adjustment tube Q1 will be reduced, thereby increasing the on-resistance of Q1, reducing the current passing through R4, and being able to keep the LED lamp bead current flowing between LED+1 and LED-1 constant.

2. The nuclear radiation resistant LED driver circuit according to claim 1, characterized in that: The power input end is a three-phase input alternating current L1, L2, L3, and the three-phase input alternating current is rectified by a rectifying circuit to become a low-ripple direct current voltage.

3. The nuclear radiation resistant LED driver circuit according to claim 2, characterized in that: The over-temperature protection circuit is a temperature switch TH1, which is connected to one phase of the three-phase input AC power and is used to cut off one phase of the three-phase input AC power and convert it into a two-phase input.

4. The nuclear radiation resistant LED driver circuit according to claim 2, characterized in that: The rectifier circuit includes rectifier diodes D1, D2, D3, D4, D5 and D6, wherein the positive electrode of the rectifier diode D1 is respectively connected to L1 and the negative electrode of the rectifier diode D2, the positive electrode of the rectifier diode D3 is respectively connected to L2 and the negative electrode of the rectifier diode D4, the positive electrode of the rectifier diode D5 is respectively connected to L3 and the negative electrode of the rectifier diode D6, the positive electrode of the rectifier diode D2 is respectively connected to the positive electrode of the rectifier diode D4 and the positive electrode of the rectifier diode D6, and the negative electrode of the rectifier diode D1, the negative electrode of D3 and the negative electrode of D5 are respectively connected to the constant current circuit.

5. The nuclear radiation resistant LED driver circuit according to claim 1, characterized in that: The filtering circuit includes a resistor R5 and a capacitor C2, one end of the resistor R5 is connected to the other end of the resistor R2, the other end of the resistor R5 is connected to one end of the capacitor C2, and the other end of the capacitor C2 is connected to the other end of the current detection resistor R4.

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