WO2015051739A1

WO2015051739A1 - Led drive

Info

Publication number: WO2015051739A1
Application number: PCT/CN2014/088157
Authority: WO
Inventors: 武俊
Original assignee: 欧普照明股份有限公司
Priority date: 2013-10-12
Filing date: 2014-10-09
Publication date: 2015-04-16
Also published as: CN104582058A

Abstract

An LED drive, comprising: a power supply unit (1), a power supply control unit (2), and an activation protection unit (3); the power supply unit (1) supplies power for a load (501) when the LED drive is connected to the load (501); the power supply control unit(2) is connected to the power supply unit(1) and controls a switching element(201) of the power supply unit(1); the activation protection unit(3) is connected to the power supply control unit(2) and activates the power supply unit (1) via a connection with the load (501). The LED drive can be activated only when being connected to the LED load (501), thus solving the problem of an electric connection failure of the LED load (501) in the LED drive circuit, thereby making the entire LED drive and LED load (501) safer.

Description

LED driver

Technical field

The invention relates to the field of lighting technology, in particular to an LED driver.

Background technique

Semiconductor lighting (LED) is a light source and display device for the third generation of semiconductor materials. It has the characteristics of low power consumption, long life, no pollution, rich color and strong controllability. It is a revolution in lighting source and light industry. With the development of LED, more and more LED lighting products are flooding into the market. The electronic drive part of the LED is an integral part of the LED lighting product.

At present, the common LED driver is used in the market. The commonly used starting line adopts the method of directly connecting the resistor, and the adopting method is simple, but in an abnormal situation, the latter part enters the abnormal protection state or enters the shutdown state, but due to the starting device If there is no setting, it will start again after entering the shutdown state, so that it will enter the abnormal protection state again or enter the shutdown state, so that the line will start again and again, leaving hidden dangers to the line safety.

In addition, at the current open circuit protection of the constant current driving circuit, the output voltage is basically higher than the voltage required for the normal working load (LED). When the driving is not connected to the load (LED), the input power is not cut off. The drive line still has a voltage output and is higher than the voltage required by the normal LED load. At this time, when the user connects the LED load, the LED load is vulnerable to transient overload and fails.

How to provide an effective protection LED driver and load is one of the urgent problems in the current lighting technology field.

Summary of the invention

The technical solution of the present invention provides an LED driver, comprising: a power supply unit, a power supply control unit, and a startup protection unit, wherein:

The power supply unit is configured to supply power to the load (501) when the LED driver is connected to the load (501);

The power supply control unit is connected to the power supply unit for controlling the switching element (201) in the power supply unit;

The boot protection unit is connected to the power supply control unit for enabling the power unit to be activated by the connection with the load (501).

Preferably, the boot protection unit is composed of a unidirectional conduction element (401) and a starting resistor (402).

Preferably, the first end of the unidirectional conduction element (401) is connected to the power supply unit, and the second end of the unidirectional conduction element (401) is connected to the first end of the starting resistor (402), and the first resistor (402) is activated. The two ends are connected to the power supply control unit.

Preferably, the power supply control unit may include a chip unit, one end of the chip unit is connected to the power supply unit, and the other end of the chip unit is connected to the startup protection unit.

Preferably, when the LED driver is connected to the load (501), the starting protection unit generates a starting current, and the switching element (201) receives the starting current for realizing the starting of the power supply unit.

Preferably, the power supply unit includes a switching element (201), a conduction through element (301), a storage and release unit (302), and a load capacitive element (304), a unidirectional conduction element (301), and a load capacitive element ( The first ends of 304) are connected in common, and the energy storage unit (302) is respectively connected to the single-conducting element (301) and the second end of the load-capacitive element (304), and one end of the switching element (201) is unidirectionally connected. The second end of the component (301) is connected.

The invention provides an LED driver, which can stop the LED driving when the LED load is not connected, and only when the LED driver has a connected LED load, the LED driver can be started to work, thereby solving the LED load in the LED driver. The problem of failure of the live connection in the line, which in turn makes the entire LED drive and LED load safer.

DRAWINGS

1 is a schematic structural view of an embodiment of the present invention;

2 is a schematic structural view of one embodiment of the present invention;

Figure 3 is a schematic structural view of the second embodiment of the present invention;

4 is a schematic structural view of a third embodiment of the present invention;

Fig. 5 is a schematic structural view of the fourth embodiment of the present invention.

detailed description

An LED driver proposed by the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

The invention provides an LED driver, which can stop the LED driving when the LED load is not connected, and only when the LED driver has a connected LED load, the LED driver can be started to work, thereby solving the LED load in the LED driver. The problem of failure of the live connection in the line, which in turn makes the entire LED drive and LED load safer. The LED driver can be used in a buck LED driving circuit, and the startup protection unit included in the LED driver includes a one-way conduction component and a starting resistor, and the startup resistor performs LED driving only when the LED driver is turned on and has an LED load. The power supply unit supplies power; when the LED load is not properly connected, the switching elements of the power supply unit in the LED drive line will not be able to obtain the starting current, thereby providing a simple open circuit protection function, that is, if no LED load is connected, the start is performed. The protection unit does not work, thus achieving the purpose of open circuit protection.

1 is a schematic structural view of an embodiment of the present invention; FIG. 2 is a schematic structural view of one embodiment of the present invention;

An LED driver includes a power supply unit 1, a power supply control unit 2, and a startup protection unit 3, wherein:

The power supply unit is configured to supply power to the load 501 when the LED driver is connected to the load 501;

The power supply control unit is connected to the power supply unit for controlling the power supply unit Switching element; achieving switching off, amplification or saturation of the switching element.

The startup protection unit is connected to the power supply control unit to implement activation of the power supply unit through connection with the load 501.

2 is a schematic structural view of one embodiment of the present invention; BUCK structure:

The start-up protection unit 3 is connected in series by a single-conducting element 401 and a start-up resistor 402. One end of the start-up protection unit 3 is connected to the power supply unit 1 and the LED load 501, respectively, and the other end is connected to the power supply control unit 2. Specifically, the first end of the unidirectional conduction element 401 is connected to the power supply unit, the second end of the unidirectional conduction element 401 is connected to the first end of the starting resistor 402, and the second end of the starting resistor 402 is connected to the power supply control unit.

In this solution, only when the LED load 501 is connected to the LED driving, the starting resistor 402 of the protection unit 3 is activated to supply power to the power supply unit 1 in the LED driving; in the case where the LED load 501 is not normally connected, the LED driving The switching element 201 of the middle power supply unit 1 will not be able to obtain the starting current, thereby providing a simple open circuit protection function, that is, if no LED load 501 is connected to the LED driving, the starting protection unit 3 will not be activated, thereby achieving the purpose of open circuit protection. .

In this solution, one end of the power supply unit 1 is connected to an input voltage, such as a DC input voltage, which may be a DC voltage or a DC ripple voltage after rectification. The other end of the power supply unit 1 is connected to the first end of the activation protection unit 3. The power supply unit 1 includes a switching element 201, a unidirectional conduction element 301, a storage energy unit 302, and a load capacitive element 304. The first end of the unidirectional conduction element 301 and the load capacitive element 303 are commonly connected to one end of the DC input voltage. And the stored energy unit 302 is connected to the single-way element 301 and the second end of the load-capable element 304, respectively. Specifically, the first end including the switching element 201, the guiding element 301, the stored energy unit 302, and the load capacitive element 304, the unidirectional conductive element 301 and the load capacitive element 304 are commonly connected, and the storage and release unit 302 is respectively Connected to the second end of the unidirectional conduction element 301 and the load capacitive element 304, one end of the switching element 201 is connected to the second end of the unidirectional conduction element 301.

One end of the power supply control unit 2 is connected to an input voltage, such as a DC input voltage, which may be a direct current. The voltage can also be a DC ripple voltage after rectification. The other end of the power supply control unit 2 is connected to the second end of the activation protection unit 3. The power supply control unit 2 includes a capacitive component 202, a resistive component 203, a secondary winding coil 303, and a unidirectional conductive component 207. The capacitive component 202 and the resistive component 203 are sequentially connected in series, and the capacitive component 202 and the resistive component are sequentially connected. One end of the 203 is connected to the secondary winding 303 of the storage unit 302 of the power supply unit 1, and the other end of the capacitive element 202 and the resistive element 203 is opposite to the base of the switching element 201 and the first end of the unidirectional element 207. Connected, the emitter of switching element 201 and the second end of unidirectional element 207 are grounded.

The start-up protection unit 3 is connected in series by a one-way conduction element 401 and a start-up resistor 402. One end of the open-circuit protection unit 3 is connected to the power supply unit 1 and the LED load 501, respectively, and the other end is connected to the power supply control unit 2. Only when the LED load 501 is turned on, the starting resistor 402 of the protection unit 3 is activated to perform power supply for the power supply control unit 2 in the LED driving; in the case where the LED load 501 is not connected normally, the switching of the power supply unit 1 in the LED driving The component 201 will not be able to obtain the starting current, thereby providing a simple open circuit protection function, that is, if no LED load 501 is connected, the startup protection unit 3 will not work, thereby achieving the purpose of open circuit protection. When the LED driver is connected to the load (501), the startup protection unit generates a startup current, that is, when the switching element (201) receives the startup current for realizing the startup of the power supply unit.

The invention is applicable to use in discrete component control, or in most chip controlled LED drivers. The activation of the LED power supply unit 1 needs to be initiated by the resistive component 402 in the protection unit 3, under normal conditions when the load 501 is connected:

First state 1: the DC input voltage may be a direct current voltage, or may be a rectified DC ripple voltage, and the resistor 402 and the switching element in the protection unit 3 are activated by the load 501 (which may be one or more) (may be The transistor or MOSFET 201 is discharged to generate a current to cause the switching element 201 to be turned on.

Then, in the second state, the switching element 201 is turned on, the DC voltage is discharged through the load capacitive element 304, the storage energy releasing unit 302 and the switching element 201, and the load capacitive element 304 starts to store energy. When the voltage across the capacitive element 304 is higher than the LED load 501, the load capacitive element 304 supplies power to the LED load 501, and the secondary winding 303 of the stored energy unit 302 generates the same potential as the stored energy unit 302. The electromotive force, the induced electromotive force is discharged by the capacitive element 202, the resistive element 203, and the base and the emitter of the switching element 201 to generate a current, causing the switching element 201 to enter a saturated conducting state while charging the capacitive element 202, along with The voltage across the capacitive element 202 increases, and the induced electromotive force drops through the capacitive element 202, the resistive element 203, and the base and emitter of the switching element 201. When the voltage across the capacitive element 202 rises to When the induced electromotive force is equal to, the switching element 201 exits the saturation conduction state.

Secondly, state three: the switching element 201 enters the saturation saturation state, the current flowing through the switching element decreases, the current of the storage energy unit 302 cannot be abruptly changed, and the reverse electromotive force is generated at both ends of the storage energy unit 302, and the electromotive force passes through a single guide. The pass element 301 and the load capacitive element 304 are discharged while the load capacitive element 304 begins to store energy. When the voltage across the load capacitive element 304 is higher than the LED load 501, the load capacitive element 304 supplies power to the LED load 501 while The secondary winding coil 303 of the stored energy unit 302 generates an induced electromotive force at the same potential as the stored energy unit 302, and the electromotive force is discharged through the unidirectional conduction element 207, the resistive element 203, and the capacitive element 202 to generate a reverse current. The switching element 201 enters an off state while the capacitive element 202 is discharged and reversely charged.

Then, state four: when the electromotive force at both ends of the stored energy unit 302 is 0, the voltage across the secondary winding coil 303 of the stored energy unit 302 is also zero, and the capacitive element 202 begins to pass through the resistive element 203 and the switching element 201. The base and the radiation stage and the secondary winding 303 are discharged to generate a current, and the switching element 201 starts to conduct.

Next, enter the sequential loop of state two.

Therefore, when the LED load 501 is not normally connected, the switching element 201 of the power supply unit 1 cannot obtain the startup current, thereby functioning as an open circuit protection.

The BUCK-Boost structure, although different from the buck structure in Figure 2, has the same:

The power supply unit 1, the power supply control unit 2 and the startup protection unit 3 are included, wherein:

The power supply control unit is connected to the power supply unit for controlling a switching element in the power supply unit; and performing switching, amplification or saturation of the switching element.

In the third and fourth embodiments of the present invention, as shown in FIGS. 4 and 5, in addition to the power supply unit 1, the power supply control unit 2, and the startup protection unit 3, a rectification filtering unit 4 may be included.

In FIG. 5, the LED power supply control unit 2 may include the illustrated structure. The power supply control unit may include a chip unit, one end of the chip unit is connected to the power supply unit, and the other end of the chip unit is connected to the startup protection unit. As shown by the LED driving in FIG. 4 and FIG. 5, when the LED driver is turned on and the LED load is turned on, the current flowing through the load is used to activate the protection unit 3, and the startup resistor 402 in the protection unit 3 is activated. The LED-driven power supply unit 1 is powered. When the LED load 501 is not properly connected, the switching element 201 of the power supply unit 1 in the LED drive line will not be able to obtain the starting current, thereby providing a simple open circuit protection function, such as When no LED load is connected to 501, the protection unit 3 is activated, thereby achieving the purpose of open circuit protection.

The above description of the preferred embodiments of the present invention is intended to be illustrative and not restrictive It is obvious that it should be included within the scope of the invention as defined by the appended claims.

Claims

An LED driver, comprising: a power supply unit, a power supply control unit, and a startup protection unit, wherein:

The power supply unit is configured to supply power to the load (501) when the LED driver is connected to the load (501);

The power supply control unit is connected to the power supply unit for controlling a switching element (201) in the power supply unit;

The startup protection unit is connected to the power supply control unit for implementing startup of the power supply unit through connection with the load (501).
The LED driver of claim 1 wherein said activation protection unit is comprised of a unidirectional conduction element (401) and a startup resistor (402).
The LED driver according to claim 2, wherein the first end of the unidirectional conduction element (401) is connected to the power supply unit, and the second end of the unidirectional conduction element (401) is coupled to the starting resistor (402). The first end is connected, and the second end of the starting resistor (402) is connected to the power supply control unit.
The LED driver according to claim 1, wherein the power supply control unit comprises a chip unit, one end of the chip unit is connected to the power supply unit, and the other end of the chip unit is connected to the startup protection unit.
The LED driver according to claim 1, wherein when the LED driver is connected to the load (501), the startup protection unit generates a starting current, and the switching element (201) The startup current is received for implementing startup of the power supply unit.
The LED driving according to claim 1, wherein the power supply unit comprises a switching element (201), a conduction element (301), a storage and release unit (302), and a load capacitive element (304), The first end of the conductive element (301) and the load capacitive element (304) are connected in common, and the energy storage unit (302) is connected to the second end of the one-way conductive element (301) and the load capacitive element (304), respectively. One end of the switching element (201) is connected to the second end of the unidirectional conduction element (301).