CN1722928B - Soft start high power DC light source - Google Patents

Abstract

A soft-start high-power DC light source, consisting of an iodine-tungsten lamp (1) and a power supply part, the power supply part includes a bridge rectifier (2), a π-shaped filter circuit (3) and a 5-volt low-voltage power supply (6), and the π-shaped filter The circuit (3) is composed of a first capacitor (C ₁ ), a sixth resistor (R ₆ ) and a second capacitor (C ₂ ). The two input terminals of the bridge rectifier (2) are connected to the 220V mains grid. The positive output terminal of (2) is connected to the positive terminal of the first capacitor (C ₁ ), and the sixth resistor (R ₆ ) is connected across the positive terminal of the first capacitor (C ₁ ) and the positive terminal of the second capacitor (C ₂ ). Between the terminals, the negative terminal of the first capacitor (C ₁ ) is connected to the negative terminal of the second capacitor (C ₂ ), and the tungsten lamp (1) is connected between the positive terminal and the negative terminal of the second capacitor (C ₂ ). It is characterized in that it also contains a current-limiting resistor (4) and a delay short-circuit circuit (5), and the current-limiting resistor (4) is connected across the negative output terminal of the bridge rectifier (2) and the first capacitor (C ₁ ), the positive power supply input terminal and the negative power supply input terminal of the delay short-circuit circuit (5) are respectively connected with the positive output terminal and the negative output terminal of the low-voltage power supply (6), and the two delay short-circuit circuit (5) The first output terminal is connected across the two ends of the current limiting resistor (4). The invention has the advantages of avoiding damage to the bridge rectifier (2) by a large charging current, highly precise time delay, and stable and reliable operation.

Description

Soft start high power DC light source

technical field

The invention relates to a soft-start high-power DC light source, specifically, a soft-start high-power DC light source that uses 220 volts of mains electricity and outputs DC light, and belongs to the technical field of high-power DC light sources.

Background technique

At present, light sources that directly use mains electricity generally output AC light, and the light intensity changes at any time. Another common light source is powered by a battery or a low-power DC power supply, which cannot provide continuous high-power and high-brightness lighting. In the occasions where high-power DC light sources are required for lighting, none of the above light sources can meet the needs.

Contents of the invention

In order to overcome the deficiency that the existing light sources cannot provide continuous high-power DC light illumination, the purpose of the present invention is to provide a soft-start high-power DC light source. The DC light source has the advantages of using 220 volt mains, soft start, and outputting high-power DC light.

The technical solution adopted by the present invention to achieve the above object is: a soft-start high-power DC light source, which is composed of an iodine-tungsten lamp 1 and a power supply part, and the power supply part includes a bridge rectifier 2, a π-shaped filter circuit 3 and a 5-volt low-voltage power supply 6 , the π-shaped filter circuit 3 is composed of the first capacitor C ₁ , the sixth resistor R ₆ and the second capacitor C ₂ , the two input terminals of the bridge rectifier 2 are connected to the 220V mains grid, and the positive output terminal of the bridge rectifier 2 is connected to the The positive end of the first capacitor _C1 is connected, the sixth resistor _R6 is connected between the positive end of the first capacitor _C1 and the positive end of the second capacitor _C2 , and the negative end of the first capacitor _C1 is connected to the second capacitor The negative terminal of _C2 is connected, and the iodine tungsten lamp 1 is connected between the positive terminal and the negative terminal of the second capacitor _C2 , and it is characterized in that it also contains a current-limiting resistor 4 and a delay short-circuit circuit 5, and the current-limiting resistor 4 Connected between the negative output terminal of the bridge rectifier 2 and the negative terminal of the first capacitor _C1 , the positive power input terminal and the negative power input terminal of the delay short-circuit circuit 5 are connected with the positive output terminal and the negative power supply input terminal of the 5-volt low-voltage power supply 6 respectively. The negative output terminal is connected, and the two output terminals of the delay short-circuit circuit 5 are connected across the two ends of the current limiting resistor 4 .

Since the iodine-tungsten lamp 1 requires relatively large power, the π-shaped filter circuit 3 needs to use filter capacitors (first capacitor C ₁ and second capacitor C ₂ ) with large capacitances. If the iodine tungsten lamp 1 is directly powered by the π-shaped filter circuit 3, that is, the resistance value of the current-limiting resistor 4 is 0, then, when such a high-power DC light source is started, that is, when the power is turned on, the charging current of the filter capacitor is very large, which will cause Bridge rectifier 2 was burned due to overcurrent. Therefore, the soft start method must be adopted when the high-power DC light source is started. In the soft-start high-power DC light source of the present invention, the π-shaped filter circuit 3 is connected in series with the current-limiting resistor 4 with a delay short-circuit circuit 5 across both ends. When the DC light source is started, the delay short-circuit circuit 5 is disconnected, and the filter capacitor is charged through the current-limiting resistor 4, and the charging current is limited by the current-limiting resistor 4 within a safe range; The current resistance 4 is short-circuited, and the charged filter capacitor continues to charge, and the charging current is still within the safe range at this time; after the filter capacitor is charged, the iodine-tungsten lamp 1 is continuously powered by the bridge rectifier 2 and the π-shaped filter circuit 3 High-power DC light is output, and at the same time, the bridge rectifier 2 will not be over-current, so that the bridge rectifier 2 is protected.

The further feature of the technical solution of the present invention is that the delay short-circuit circuit 5 is composed of a first resistor R ₁ , a second resistor R ₂ , a third resistor R ₃ , a fourth resistor R ₄ , a fifth resistor R ₅ , a relay RLY, and a second resistor RLY. A diode D ₁ , a second diode D ₂ , a triode Q ₁ , a MOS tube Q, a voltage comparator U ₁ , and a single-chip computer system MCU, the relay RLY is a DC5V single-pole double-throw relay, and the voltage comparator U The model of ₁ is LM393, and the model of MCU of the single-chip computer system is AT89C51. The first resistor _R1 and the second resistor _R2 are connected in series and connected between the positive terminal of the second capacitor _C2 and the negative output terminal of the bridge rectifier 2. The connection point of the first resistor _R1 and the second resistor _R2 is connected to the common terminal com of the relay RLY, the gate g, the normally open terminal no are connected together with one end of the third resistor _R3 , and the other end of the third resistor _R3 It is connected to the negative output terminal of the bridge rectifier 2, the source s, one end of the current limiting resistor 4 are connected to the negative output terminal of the bridge rectifier 2, the drain d, the other end of the current limiting resistor 4 are connected to the first capacitor C The negative terminals of ₁ are connected together, the positive terminal VCC and the ground terminal GND of the voltage comparator _U1 are respectively connected to the positive terminal and negative terminal of the 5-volt low-voltage power supply 6, the negative terminal of the 5-volt low-voltage power supply 6 is grounded, and the first diode The tube D ₁ and the second diode D ₂ are connected in series in the forward direction and then connected between the positive terminal of the 5-volt low-voltage power supply 6 and the non-inverting input terminal A+, and the inverting input terminal A- is connected to the port P2.2 of the microcontroller system MCU , the relay RLY is connected across the positive terminal of the 5-volt low-voltage power supply 6 and the collector c, the emitter e is connected to the negative terminal of the 5-volt low-voltage power supply 6, and the fifth resistor _R5 is connected across the positive terminal of the 5-volt low-voltage power supply 6 Between the terminal and the output terminal Aout of the voltage comparator _U1 , the fourth resistor _R4 is connected between the output terminal Aout of the voltage comparator _U1 and the base b.

The soft-start high-power DC light source of the present invention starts, that is, after starting up, the port P2. Output low signal, base b voltage is lower than 0.6V, transistor Q ₁ is cut off, relay RLY is not excited, common terminal com is connected to normally closed terminal nc, gate g-source s voltage is 0V, MOS tube Q is cut off, The current limiting resistor 4 is connected in series with the first capacitor C ₁ to limit the power-on charging current of the first capacitor C ₁ to a safe range. After a delay of several hundred milliseconds, the delay short-circuit circuit 5 acts: the port P2.2 outputs a low-level signal, the voltage of the input signal at the positive-phase input terminal A+ is higher than the voltage of the input signal at the inverting input terminal A-, and the output terminal Aout outputs High signal, base b voltage is higher than 0.6V, transistor Q ₁ is turned on, relay RLY is excited, common terminal com and normally open terminal no are connected, gate g-source s voltage is positive voltage, MOS transistor Q is turned on, The current limiting resistor 4 is short-circuited, and the partially charged first capacitor _C1 continues to charge until the first capacitor _C1 is fully charged, and its charging current is always within a safe range. The iodine-tungsten lamp 1 is connected across the two ends of the power supply part, that is, the two ends of the second capacitor C ₂ , and the iodine-tungsten lamp 1 continuously outputs high-power DC light due to being powered. At the same time, the soft start circuit limits the current flowing through the bridge rectifier 2 within a safe range, so that the bridge rectifier 2 is protected. In addition, the delay signal output by the port P2.2 is generated by the single-chip system MCU, and the delay is highly precise to ensure that the delay short-circuit circuit 5 can work reliably and stably.

Compared with the background technology, the beneficial effect of the present invention is that the soft start circuit of the present invention reduces the charging current of the first capacitor _C1 during start-up, and the current flowing through the bridge rectifier 2 decreases accordingly, avoiding large charging The current damages the bridge rectifier 2; the delay signal of the delay short-circuit circuit 5 is provided by the single-chip system MCU, and the delay is highly precise, ensuring that the DC light source of the present invention works stably and reliably.

Description of drawings

Fig. 1 is a structural block diagram of the soft-start high-power DC light source of the present invention.

Fig. 2 is a circuit diagram of the soft-start high-power DC light source of the present invention.

Fig. 3 is a schematic diagram of the charging current of the first capacitor C ₁ and the second capacitor C ₂ exceeding the safe range when the high-power DC light source without a current-limiting resistor and a delay short-circuit circuit is started.

Fig. 4 is a schematic diagram showing that the charging currents of the first capacitor _C1 and the second capacitor _C2 are within a safe range when the soft-start high-power DC light source of the present invention is started.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

In FIG. 2 , the current limiting resistor 4 and the delay short-circuit circuit 5 are inside the dotted line box. The source s and the drain d of the MOS transistor Q are the two output terminals of the delay short-circuit circuit 5 and are connected across the two ends of the current limiting resistor 4 . Other circuit connections have been described in detail in the "Summary of the Invention", and will not be repeated here.

Example

The circuit of this embodiment is shown in FIG. 2 . List the components and parts models or parameters adopted in this embodiment as follows:

Iodine tungsten lamp 1 500 watt iodine tungsten lamp

Bridge rectifier 2 whose model is KBPC3510

1st Resistor R ₁ 150 kohm, 1/4 Watt

Second resistor _R2 10k ohm, 1/4 watt

Third Resistor _R3 1 Mohm, 1/4 Watt

Fourth resistor _R4 240 ohms, 1/4 watt

5th Resistor _R5 3 kohm, 1/4 Watt

Sixth Resistor R ₆ 10 Ohm Ceramic Resistor, 300 Watts

Current limiting resistor4 30 ohm ceramic resistor, 20 watts

MOS tube Q its model is MTY30N60E

The first capacitor C ₁ 100 microfarad electrolytic capacitor, withstand voltage 400 volts

The second capacitor C ₂ 1000 microfarad electrolytic capacitor, withstand voltage 400 volts

The first diode D ₁ whose model is 1N4148

The second diode D ₂ its type is 1N4148

The model of transistor Q ₁ is 9013

In this embodiment, the current-limiting resistor is short-circuited after a delay of 200 milliseconds after starting up, and the effect of reducing the charging current is obtained. See Figure 4.

Claims (2)

1. A soft-start high-power DC light source, consisting of an iodine-tungsten lamp (1) and a power supply part, the power supply part includes a bridge rectifier (2), a π-shaped filter circuit (3) and a 5-volt low-voltage power supply (6), π The shape filter circuit (3) is composed of a first capacitor (C ₁ ), a sixth resistor (R ₆ ) and a second capacitor (C ₂ ). The positive output terminal of the type rectifier (2) is connected to the positive terminal of the first capacitor (C ₁ ), and the sixth resistor (R ₆ ) is connected across the positive terminal of the first capacitor (C ₁ ) and the second capacitor (C ₂ ). Between the positive terminals of the first capacitor (C ₁ ), the negative terminal of the first capacitor (C 1 ) is connected to the negative terminal of the second capacitor (C ₂ ), and the tungsten lamp (1) is connected across the positive terminal and the negative terminal of the second capacitor (C ₂ ). It is characterized in that it also contains a current-limiting resistor (4) and a time-delay short-circuit circuit (5), and the current-limiting resistor (4) is connected across the negative output terminal of the bridge rectifier (2) and the first capacitor ( Between the negative terminals of C ₁ ), the positive power supply input terminal and the negative power supply input terminal of the delay short-circuit circuit (5) are respectively connected with the positive output terminal and the negative output terminal of the 5-volt low-voltage power supply (6), and the delay short-circuit circuit ( 5) The two output terminals are connected across the two ends of the current-limiting resistor (4), and the delay short-circuit circuit (5) is composed of the first resistor (R ₁ ), the second resistor (R ₂ ), the third resistor (R ₃ ), fourth resistor (R ₄ ), fifth resistor (R ₅ ), relay (RLY), first diode (D ₁ ), second diode (D ₂ ), transistor (Q ₁ ), MOS Tube (Q), voltage comparator (U ₁ ) _, and single-chip microcomputer system (MCU). ) model is AT89C51, the first resistor (R ₁ ) and the second resistor (R ₂ ) are connected in series between the positive terminal of the second capacitor (C ₂ ) and the negative output terminal of the bridge rectifier (2), The connection point of the first resistor (R ₁ ) and the second resistor (R ₂ ) is connected to the common terminal (com) of the relay (RLY), the gate (g), the normally open terminal (no) and the third resistor (R ₃ ) One end of the third resistor (R ₃ ) is connected to the negative output end of the bridge rectifier (2), the source (s), one end of the current limiting resistor (4) is connected to the bridge rectifier (2) The negative output terminals of the voltage comparator (U 1 ) are connected together, _the drain (d), the other end of the current limiting resistor (4) and the negative terminal of the first capacitor (C ₁ ) are connected together, and the positive terminal (VCC ) and the ground terminal (GND) are respectively connected to the positive terminal and the negative terminal of the 5-volt low-voltage power supply (6), the negative terminal of the 5-volt low-voltage power supply (6) is grounded, and the first diode (D ₁ ) and the second diode The tube (D ₂ ) is connected in series in the forward direction and connected between the positive terminal of the 5-volt low-voltage power supply (6) and the non-inverting input terminal (A+), and the inverting input terminal (A-) and the terminal of the single-chip microcomputer system (MCU). Port P2.2 is connected, the relay (RLY) is connected between the positive terminal of the 5-volt low-voltage power supply (6) and the collector (c), and the emitter (e) is connected to the negative terminal of the 5-volt low-voltage power supply (6). The fifth resistor (R ₅ ) is connected between the positive terminal of the 5 volt low-voltage power supply (6) and the output terminal (Aout) of the voltage comparator (U ₁ ), and the fourth resistor (R ₄ ) is connected across the voltage comparator (U ₁ ) between the output terminal (Aout) and the base (b). 2. The soft-start high-power DC light source according to claim 1, characterized in that the types or parameters of the components used are listed as follows: Iodine Tungsten Lamp (1) 500W Iodine Tungsten Lamp Bridge rectifier (2) whose model is KBPC3510 First resistor (R ₁ ) 150 kohm, 1/4 watt Second resistor (R ₂ ) 10 kohm, 1/4 watt Third Resistor (R ₃ ) 1 Mohm, 1/4 Watt Fourth resistor (R ₄ ) 240 ohms, 1/4 watt Fifth resistor (R ₅ ) 3 kohm, 1/4 watt Sixth Resistor (R ₆ ) 10 Ohm Ceramic Resistor, 300 Watts Current limiting resistors (4) 30 ohm ceramic resistors, 20 watts MOS tube (Q) whose model is MTY30N60E The first capacitor (C ₁ ) is a 100 microfarad electrolytic capacitor with a withstand voltage of 400 volts The second capacitor (C ₂ ) is a 1000 microfarad electrolytic capacitor with a withstand voltage of 400 volts The first diode (D ₁ ) is 1N4148 The second diode (D ₂ ) is 1N4148 Transistor (Q ₁ ) whose model is 9013 The delay time of the delay short-circuit circuit (5) is 200 milliseconds.

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