CN203015236U - A LED drive power supply - Google Patents

Abstract

The utility model relates to a LED field of making provides a LED drive power supply, including the LED lamps and lanterns of the power input end, EMC circuit, rectifier circuit, voltage conversion circuit, filter circuit, output current voltage detection circuitry and the output that connect gradually, still include constant current constant voltage control circuit simultaneously, be connected with output current voltage detection circuitry's output and voltage conversion circuitry's input respectively rectifier circuit with an inductance of establishing ties between the voltage conversion circuit and a piezo-resistor of parallelly connected, piezo-resistor's input and the output of inductance are connected. The utility model discloses reduced bulky, the fault rate is high, the component of price by a wide margin, simple structure is reasonable, cost reduction uses reliable and stable. Inductance is added between the rectifying circuit and the voltage conversion circuit, and adverse effects caused by conduction of differential mode signals to a power grid are suppressed. Meanwhile, the voltage dependent resistor is added, and the suppression capability of the power supply to external surge is improved.

Description

A LED drive power supply

technical field

The utility model relates to the field of LED manufacturing, in particular to a stable and reliable LED driving power supply with simple and reasonable structure, reduced cost.

Background technique

LED, light-emitting diode, is a semiconductor component that can convert electrical energy into light energy. It has the advantages of small size, low power consumption, long service life, environmental protection and durability, and is widely used in lighting fixtures, display screens, traffic lights, etc. field.

Since the LED is a semiconductor device with sensitive characteristics and has negative temperature characteristics, it needs to be in a stable working state and protected during the application process, thus requiring an LED drive power supply. LEDs have very strict requirements on driving power, unlike ordinary incandescent bulbs, which can be directly connected to 220V AC mains. LED is driven by a low voltage of 2 to 3V, and a complex conversion circuit must be designed. At present, when selecting and designing LED driving power, it is necessary to consider high reliability, high efficiency, high power factor, surge protection, service life, and adaptation.

In the prior art, as shown in Figure 1, the traditional high-power LED drive power supply is powered by the input terminal of the AC power supply, which is sequentially input to the EMC circuit, rectification circuit, PFC circuit, voltage conversion circuit, filter circuit, output current and voltage detection circuit and LED lamps on the output side. At the same time, there is also a constant current and constant voltage control circuit, including amplifying drive and driving circuit, which is sequentially output from the output terminal of the output current and voltage detection circuit to the input terminal of the amplifying drive, driving circuit, and voltage conversion circuit, providing constant current and constant voltage drive for LED. . Among them, the PFC circuit also forms a loop together with the DC power supply and the power factor control circuit.

This traditional high-power LED drive power supply is relatively complex, and some of its components have the disadvantages of large volume, high power, high cost, and high failure rate, such as high-power MOS tubes, high-frequency transformers, recovery diodes, electrolytic capacitors, etc., making The entire circuit has high energy consumption, low work efficiency, high overall cost, and lack of stability and reliability in use.

Utility model content

The technical problem to be solved by the utility model is to provide a stable and reliable LED driving power supply with simple and reasonable structure, improved work efficiency, reduced cost.

The technical solution adopted by the utility model to solve the technical problem is: a LED drive power supply, including a power input terminal, an EMC circuit, a rectification circuit, a voltage conversion circuit, a filter circuit, an output current and voltage detection circuit and an LED output terminal connected in sequence. The lamp also includes a constant current and constant voltage control circuit, which is respectively connected to the output terminal of the output current and voltage detection circuit and the input terminal of the voltage conversion circuit, and an inductor is connected in series between the rectification circuit and the voltage conversion circuit and an inductor is connected in parallel. The varistor, the input terminal of the varistor is connected with the output terminal of the inductor.

The LED drive power supply of the utility model is powered by the power supply input terminal, which is sequentially input to the EMC circuit, the rectification circuit, the voltage conversion circuit, the filter circuit, the output current voltage detection circuit and the LED lamp at the output end, wherein the EMC circuit performs a check on the external electromagnetic interference signal Suppression; the rectifier circuit converts the AC power input by the power supply into DC power; the voltage conversion circuit converts the high-voltage DC into the required low-voltage DC signal; the filter circuit reduces the AC component in the pulsating low-voltage DC signal as much as possible, and retains the DC components, reduce the ripple coefficient of the output voltage, and make the waveform smoother; the output current and voltage detection circuit detects the output current and voltage signal and feeds it back to the voltage conversion circuit through the constant current and constant voltage control circuit to provide constant current and constant voltage for the LED. pressure drive.

Compared with the traditional high-power LED drive power supply, the utility model cancels the PFC circuit, thus does not need to use the high-power MOS tube and high-frequency transformer in the PFC circuit, and cancels the connection between the PFC circuit and the voltage conversion circuit in Figure 1 at the same time. Between the high power, high reverse voltage, fast recovery diode D2 and large volume, large capacity, high voltage electrolytic capacitor C20. The above-mentioned components are all components with high power, large volume, high failure rate and high price. The utility model greatly reduces these components, so that the structure is simple and reasonable, the work efficiency can be effectively improved, the cost is reduced, and the work is stable and reliable. In addition, an inductance is added between the rectification circuit and the voltage conversion circuit to suppress the adverse effects caused by the transmission of the differential mode signal to the power grid. At the same time, due to the cancellation of the high withstand voltage electrolytic capacitor C20, a piezoresistor is added between the rectification circuit and the voltage conversion circuit as compensation for improving the ability of the power supply to suppress external surges.

In one embodiment, the constant current and constant voltage control circuit includes an amplifying drive and a power factor control circuit, the input end of the amplifying drive is connected to the output end of the output current and voltage detection circuit, and the output end of the amplifying drive is connected to the power factor control circuit. The input end is connected, and the output end of the power factor control circuit is connected with the input end of the voltage conversion circuit. The amplifying drive generates corresponding control signals after amplifying and analyzing the output current and voltage signals, and sends them to the power factor control circuit. voltage control. Compared with the traditional high-power LED driving circuit, the driving circuit is eliminated, which further simplifies the overall structure.

In one embodiment, an overvoltage protection circuit is connected between the rectification circuit and the power factor control circuit, the input end of the overvoltage protection circuit is connected to the output end of the rectification circuit, and the output end of the overvoltage protection circuit is connected to the power factor control circuit. The input terminal of the circuit is connected. When the voltage of the rectifier circuit is higher than a certain value, the overvoltage protection circuit sends the signal to the power factor control circuit to control and cut off the voltage conversion circuit; when the voltage returns to the normal range, the overvoltage protection circuit sends the signal to the power factor control circuit The circuit is used to control the switching on of the voltage conversion circuit.

In one embodiment, an over-temperature protection circuit is connected to the input end of the amplified drive. When the temperature of the LED lamp is too high, the over-temperature protection circuit sends the signal to the amplifying driver, and then the power factor control circuit controls the forced reduction of the output current of the voltage conversion circuit to avoid damage to the LED lamp due to excessive temperature and further improve the operating efficiency. Stable and reliable.

In one embodiment, the input end of the amplifying drive is connected with an output short-circuit open-circuit protection circuit. When the circuit is short-circuited, it will automatically cut off the circuit to realize its own effective protection and send out an alarm to prevent further damage. After a few seconds, it will restart. If the circuit is still short-circuited, it will cut off the circuit again and continue to patrol until the fault is eliminated.

In a preferred embodiment, the model of the power factor control circuit is L6561, which can adjust the overvoltage output very precisely, has a very small starting current and a very low operating current, and is an upgrade of the power factor corrector of the L6560 specification Version, with more superior performance, can allow to work in a wide effective input voltage range (from 85V to 265V), compress the startup current to as low as tens of microamps and have a function stop device to ensure standby mode lower current consumption.

The utility model makes full use of the excellent performance of the power factor L6561: it has the current zero-crossing detection function, which not only effectively avoids the adverse consequences of the transformer due to saturation, but also reduces the switching loss of the MOS tube and greatly improves the conversion efficiency of the entire power circuit; it By detecting the rectified pulsed DC voltage, the output frequency and duty cycle are automatically adjusted to improve the conversion efficiency and power factor of the circuit; it has the overcurrent protection function of the MOS tube, and when the current of the MOS tube reaches a certain value, it will be cut off instantly MOS tube, effectively protects the MOS tube, makes the operation reliable and prolongs the service life. the

The beneficial effects of the utility model are: the utility model greatly reduces components with large volume, high failure rate and high price, has a simple and reasonable structure, can effectively improve work efficiency, and reduce costs. The power factor can be as high as PF=0.95 or more, which is in line with the Class A standard of national street lighting. An inductance is added between the rectification circuit and the voltage conversion circuit to resist adverse effects caused by differential mode signal conduction to the power grid. At the same time, a varistor is added between the rectification circuit and the voltage conversion circuit to improve the ability of the power supply to suppress external surges. In addition, an over-voltage protection circuit and an over-temperature protection circuit are added to further improve the stability and reliability of use. the

Description of drawings

FIG. 1 is a schematic structural diagram of a conventional high-power LED driving power supply in the prior art.

Fig. 2 is a schematic structural view of Embodiment 1 of the utility model.

Fig. 3 is a schematic structural view of Embodiment 2 of the utility model.

Fig. 4 is a schematic structural view of Embodiment 3 of the present utility model.

Fig. 5 is a schematic structural view of Embodiment 4 of the present utility model.

Other components irrelevant to the design points of the present utility model are omitted among the figures.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment, the utility model is described in further detail.

Example 1

As shown in Fig. 2, a kind of LED drive power supply of the present utility model comprises the power supply input terminal 101, EMC circuit 102, rectification circuit 103, voltage conversion circuit 104, filter circuit 105, output current voltage detection circuit 106 and output LED light fixture 107 at the end. It also includes a constant current and constant voltage control circuit, including an amplifying drive 108 and a power factor control circuit 109, the input end of the amplifying drive 108 is connected to the output end of the output current voltage detection circuit 106, and the output end of the amplifying drive 108 is connected to the power factor control circuit 109 The input end of the power factor control circuit 109 is connected to the input end of the voltage conversion circuit 104 . At the same time, an inductor L3 and a piezoresistor YM3 are connected in series between the rectifier circuit 103 and the voltage conversion circuit 104, and the input terminal of the piezoresistor YM3 is connected to the output terminal of the inductor L3.

The LED driving power supply of the present utility model is powered by the power supply input terminal 101. In the present embodiment, an AC220V power supply is used, which is sequentially input to the EMC circuit 102, the rectification circuit 103, the voltage conversion circuit 104, the filter circuit 105, the output current voltage detection circuit 106 and The LED lamp 107 at the output end, wherein the EMC circuit 102 suppresses the external electromagnetic interference signal; the rectification circuit 103 converts the AC power input by the power supply into DC power; the voltage conversion circuit 104 converts the high-voltage DC into the required low-voltage DC signal, It mainly includes MOS transistor Q1 and winding T1, and a capacitor C6 is connected in parallel between the rectifier circuit 103 and the voltage conversion circuit 104 to form an LC circuit with the inductor L3; the filter circuit 105 reduces the AC component in the pulsating DC voltage as much as possible, Retain the DC component, reduce the ripple coefficient of the output voltage, and make the waveform smoother, mainly including the diode D1 and the capacitor C30; the output current and voltage detection circuit 106 detects the output current and voltage signal and sends it to the amplifying driver 108, and the amplifying and driving 108 generates a corresponding control signal after amplifying and analyzing the output current and voltage signal, and sends it to the power factor control circuit 109. voltage control. An optical coupling device U3 and a capacitor C22 are connected in series between the amplification drive 108 and the power factor control circuit 109. When the output voltage value of the output current and voltage detection circuit 106 fluctuates, the power factor control circuit 109 will automatically change the output control signal. Duty ratio, thereby changing the conduction time of the MOS transistor Q1 in the voltage conversion circuit 104, thereby changing the output current and voltage, and realizing the effective regulation of constant current and constant voltage.

In this embodiment, the model of the power factor control circuit 109 is L6561, which is powered by a DC12V power supply 110 and can adjust the overvoltage output very accurately. The utility model makes full use of the excellent performance of the power factor L6561: it has the current zero-crossing detection function, which not only effectively avoids the adverse consequences of the transformer due to saturation, but also reduces the switching loss of the MOS tube and greatly improves the conversion efficiency of the entire power circuit; it By detecting the rectified pulsed DC voltage, the output frequency and duty cycle are automatically adjusted to improve the conversion efficiency and power factor of the circuit; it has the overcurrent protection function of the MOS tube, and when the current of the MOS tube reaches a certain value, it will be cut off instantly MOS tube, effectively protects the MOS tube, makes the operation reliable and prolongs the service life.

In this embodiment, the input end of the amplification driver 108 is connected with an output short-circuit open-circuit protection circuit. When a short circuit is detected, the circuit will be automatically cut off and an alarm will be issued to prevent further damage. After a few seconds, it will be restarted. If the short circuit is still present, the circuit will be cut off again and the circuit will continue until the fault is eliminated.

As shown in Fig. 1 and Fig. 2, compared with the traditional high-power LED drive power supply, the utility model cancels the PFC circuit, so that it does not need to use high-power MOS tubes and high-frequency transformers in the PFC circuit, and at the same time cancels the PFC A high-power, high reverse voltage, fast recovery diode D2 and a large-volume, large-capacity, high-voltage-resistant electrolytic capacitor C20 between the circuit and the voltage conversion circuit. The above-mentioned components are all components with high power, large volume, high failure rate and high price. The utility model greatly reduces these components, so that the structure is simple and reasonable, the work efficiency can be effectively improved, the cost is reduced, and the work is stable and reliable. At the same time, the drive circuit is also eliminated, further simplifying the overall structure. In addition, an inductance L3 is added between the rectification circuit and the voltage conversion circuit to suppress adverse effects caused by the transmission of differential mode signals to the power grid. At the same time, due to the cancellation of the high withstand voltage electrolytic capacitor C20, a piezoresistor YM3 is added between the rectification circuit and the voltage conversion circuit as compensation for improving the ability of the power supply to suppress external surges.

Example 2

As shown in Figure 3, the difference between this embodiment and Embodiment 1 is that in this embodiment, an overvoltage protection circuit 111 is connected between the rectifier circuit 103 and the power factor control circuit 109, and the overvoltage protection circuit 111 The input terminal of the overvoltage protection circuit 111 is connected to the output terminal of the rectification circuit 103, and the output terminal of the overvoltage protection circuit 111 is connected to the input terminal of the power factor control circuit 109. When the voltage of the rectifier circuit 103 is higher than a certain value, the overvoltage protection circuit 111 sends the signal to the power factor control circuit 109 to control and cut off the voltage conversion circuit 104; when the voltage returns to the normal range, the overvoltage protection circuit 111 sends the signal The output is sent to the power factor control circuit 109, and the voltage conversion circuit 104 is controlled to be turned on. the

Other structures are the same as in Embodiment 1.

Example 3

As shown in FIG. 4 , the difference between this embodiment and Embodiment 1 lies in that: in this embodiment, the input terminal of the amplification driver 108 is connected with an over-temperature protection circuit 112 . When the temperature of the LED lamp 107 is too high, the over-temperature protection circuit 112 sends the signal to the amplifying driver 108, and the voltage fed back from the amplifying driver 108 to the power factor control circuit 109 increases, and then the power factor control circuit 109 makes the output control signal The duty cycle is reduced, and then the conduction time of the MOS transistor Q1 in the voltage conversion circuit 104 is controlled to be shortened, thereby forcibly reducing the output current, avoiding damage to the LED lamp due to excessive temperature, and further improving the stability and reliability of use. the

Other structures are the same as in Embodiment 1.

Example 4

As shown in Figure 5, the difference between this embodiment and Embodiment 1 is that in this embodiment, an overvoltage protection circuit 111 is connected between the rectification circuit 103 and the power factor control circuit 109, and the overvoltage protection circuit 111 The input terminal of the overvoltage protection circuit 111 is connected to the output terminal of the rectification circuit 103, and the output terminal of the overvoltage protection circuit 111 is connected to the input terminal of the power factor control circuit 109. When the voltage of the rectifier circuit 103 is higher than a certain value, the overvoltage protection circuit 111 sends the signal to the power factor control circuit 109 to control and cut off the voltage conversion circuit 104; when the voltage returns to the normal range, the overvoltage protection circuit 111 sends the signal The output is sent to the power factor control circuit 109, and the voltage conversion circuit 104 is controlled to be turned on.

At the same time, in this embodiment, the input terminal of the amplification driver 108 is also connected with an over-temperature protection circuit 112 . When the temperature of the LED lamp 107 is too high, the over-temperature protection circuit 112 sends the signal to the amplifying driver 108, and the voltage fed back from the amplifying driver 108 to the power factor control circuit 109 increases, and then the power factor control circuit 109 makes the output control signal The duty cycle is reduced, and then the conduction time of the MOS transistor Q1 in the voltage conversion circuit 104 is controlled to be shortened, thereby forcibly reducing the output current, avoiding damage to the LED lamp due to excessive temperature, and further improving the stability and reliability of use. the

Other structures are the same as in Embodiment 1.

The above are only preferred embodiments of the present utility model, but the design concept of the present utility model is not limited thereto, and all non-essential modifications made to the utility model by using this concept also fall within the scope of protection of the present utility model Inside.

Claims (6)

1. LED driving power, it is characterized in that, the LED light fixture that comprises the power input, EMC circuit, rectification circuit, voltage conversion circuit, filter circuit, output current voltage detecting circuit and the output that connect successively, also comprise simultaneously constant-current and constant-voltage control circuit, being connected input with voltage conversion circuit with the output of output current voltage detecting circuit respectively is connected, connect between described rectification circuit and described voltage conversion circuit an inductance and piezo-resistance in parallel, the input of piezo-resistance is connected with the output of inductance.

2. LED driving power according to claim 1, it is characterized in that, described constant-current and constant-voltage control circuit comprises that amplification drives, power factor control circuit, amplifying the input that drives is connected with the output of output current voltage detecting circuit, amplify the output that drives and be connected with the input of power factor control circuit, the output of power factor control circuit is connected with the input of voltage conversion circuit.

3. LED driving power according to claim 2; it is characterized in that; be connected with overvoltage crowbar between described rectification circuit and power factor control circuit; the input of overvoltage crowbar is connected with the output of rectification circuit, and the output of overvoltage crowbar is connected with the input of power factor control circuit.

4. LED driving power according to claim 2, is characterized in that, the input that described amplification drives is connected with thermal-shutdown circuit.

5. LED driving power according to claim 2, is characterized in that, the input that described amplification drives is connected with the output short-circuit open loop protection circuit.

6. the described LED driving power of according to claim 2 to 5 any one, is characterized in that, the model of described power factor control circuit is L6561.

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