LED drive circuit and projector
阅读说明:本技术 Led驱动电路及投影仪 (LED drive circuit and projector ) 是由 高文刚 于 2020-06-04 设计创作,主要内容包括:本发明公开一种LED驱动电路及投影仪,投影仪包括红绿蓝三色LED灯,该LED驱动电路包括:LED驱动器,被配置为输出LED驱动信号;扩流电路,扩流电路的受控端与LED驱动器连接,扩流电路的输出端与红绿蓝三色LED灯中至少一个LED灯的一电极连接;开关控制电路,开关控制电路的受控端与LED驱动器连接,开关控制电路的输出端与红绿蓝三色LED灯中至少一个LED灯的另一电极连接;其中,扩流电路和开关控制电路在接收到LED驱动信号时工作,以点亮LED灯。本发明无需改变LED驱动器的程序和输出,在原有的驱动架构下,能够实现提高LED驱动电流。(The invention discloses an LED drive circuit and a projector, wherein the projector comprises a red, green and blue LED lamp, and the LED drive circuit comprises: an LED driver configured to output an LED driving signal; the controlled end of the current expansion circuit is connected with the LED driver, and the output end of the current expansion circuit is connected with one electrode of at least one LED lamp in the red, green and blue LED lamps; the controlled end of the switch control circuit is connected with the LED driver, and the output end of the switch control circuit is connected with the other electrode of at least one LED lamp in the red, green and blue LED lamps; the current expansion circuit and the switch control circuit work when receiving the LED driving signal to light the LED lamp. The invention can improve the LED driving current under the original driving framework without changing the program and the output of the LED driver.)
1. An LED drive circuit is applied to a projector, the projector comprises a red, green and blue LED lamp, and the LED drive circuit is characterized by comprising:
an LED driver configured to output an LED driving signal;
the controlled end of the current expansion circuit is connected with the LED driver, and the output end of the current expansion circuit is connected with one electrode of at least one LED lamp in the red, green and blue LED lamps;
the controlled end of the switch control circuit is connected with the LED driver, and the output end of the switch control circuit is connected with the other electrode of at least one LED lamp in the red, green and blue LED lamps; the current expansion circuit and the switch control circuit work when receiving the LED driving signal to light the LED lamp.
2. The LED driving circuit according to claim 1, wherein the current spreading circuit has two output terminals, and the two output terminals of the current spreading circuit are respectively connected to the blue LED lamps and the green LED lamps of the three-color red, green and blue LED lamps in a one-to-one correspondence manner;
the switch control circuit comprises a first electronic switch and a second electronic switch, and the first electronic switch and the second electronic switch are respectively connected with blue LED lamps and green LED lamps in red, green and blue LED lamps in a one-to-one correspondence mode.
3. The LED driver circuit of claim 2, wherein the LED driver includes a first LED driving signal output and a second LED driving signal output, the first LED driving signal output of the LED driver being connected to the current spreading circuit and the switch control circuit, respectively;
and a second LED driving signal output end of the LED driver and a red LED lamp in the red, green and blue LED lamps.
4. The LED driving circuit according to claim 3, further comprising a first diode and a second diode, anodes of the first diode and the second diode being respectively connected to the controlled terminal of the current spreading circuit; and the cathodes of the first diode and the second diode are connected with a first driving signal output end of the LED driver.
5. The LED driving circuit according to claim 2, wherein the projector further comprises a Bp LED lamp, one of the two output terminals of the current spreading circuit is further connected to an electrode of the Bp LED lamp; one of the two output ends of the switch control circuit is also connected with the other end of the Bp LED lamp.
6. The LED driving circuit of claim 1, wherein the current spreading circuit comprises a first current spreading branch and a second current spreading branch;
the two output ends of the first current expansion branch are respectively connected with blue LED lamps and green LED lamps in red, green and blue LED lamps in a one-to-one correspondence manner;
the switch control circuit comprises a first switch control branch and a second switch control branch; the first switch control branch comprises a first electronic switch and a second electronic switch, and the first electronic switch and the second electronic switch are respectively connected with blue LED lamps and green LED lamps in red, green and blue LED lamps in a one-to-one correspondence manner;
the output end of the second current expanding branch circuit is connected with one electrode of a red LED lamp in the red, green and blue LED lamps, and the output end of the second switch control branch circuit is connected with the other electrode of the red LED lamp in the red, green and blue LED lamps.
7. The LED driving circuit according to claim 6, wherein the projector further comprises a Bp LED lamp, one of the two output terminals of the first current spreading branch is further connected to an electrode of the Bp LED lamp; one of the two output ends of the first switch control branch is also connected with the other end of the Bp LED lamp.
8. The LED driving circuit according to claim 6, further comprising a third diode, a fourth diode and a fifth diode, wherein anodes of the third diode and the fourth diode are respectively connected to the controlled end of the first current spreading branch; cathodes of the third diode and the fourth diode are connected with a first driving signal output end of the LED driver;
and the anode of the fifth diode is connected with the controlled end of the second current spreading branch, and the cathode of the fifth diode is connected with the second driving signal output end of the LED driver.
9. The LED driving circuit according to any one of claims 1 to 8, further comprising an LED controller, wherein an output terminal of the LED controller is connected to the LED driver; the LED controller is configured to output a corresponding LED control signal to the LED driver according to the received image data.
10. A projector characterized by comprising the LED driving circuit according to any one of claims 1 to 9.
Technical Field
The invention relates to the technical field of LED driving, in particular to an LED driving circuit and a projector.
Background
The LED is applied to various devices, for example, in a projector, in actual use, as the brightness requirement of the LED is continuously increased, the driving current is continuously increased, and the driving range of the LED driving chip provided by TI is limited, which cannot meet the requirement of increasing the LED driving current again under the existing driving current of the DLP projector, if the driving current is to be increased, the program of the DLP driver and the peripheral circuit thereof need to be changed, so that the existing TI DLP driving system cannot be used.
Disclosure of Invention
The invention mainly aims to provide an LED driving circuit and a projector, and aims to improve the current driving capability of an LED.
In order to achieve the above object, the present invention provides an LED driving circuit, which is applied to a projector, wherein the projector includes a red, green and blue LED lamp, and the LED driving circuit includes:
an LED driver configured to output an LED driving signal;
the controlled end of the current expansion circuit is connected with the LED driver, and the output end of the current expansion circuit is connected with one electrode of at least one LED lamp in the red, green and blue LED lamps;
the controlled end of the switch control circuit is connected with the LED driver, and the output end of the switch control circuit is connected with the other electrode of at least one LED lamp in the red, green and blue LED lamps; the current expansion circuit and the switch control circuit work when receiving the LED driving signal to light the LED lamp.
Optionally, the number of the output ends of the current amplifying circuit is two, and the two output ends of the current amplifying circuit are respectively connected with the blue LED lamp and the green LED lamp in the red, green and blue three-color LED lamp in a one-to-one correspondence manner;
the switch control circuit comprises a first electronic switch and a second electronic switch, and the first electronic switch and the second electronic switch are respectively connected with blue LED lamps and green LED lamps in red, green and blue LED lamps in a one-to-one correspondence mode.
Optionally, the LED driver includes a first LED driving signal output end and a second LED driving signal output end, and the first LED driving signal output end of the LED driver is connected to the current expanding circuit and the switch control circuit, respectively;
and a second LED driving signal output end of the LED driver and a red LED lamp in the red, green and blue LED lamps.
Optionally, the LED driving circuit further includes a first diode and a second diode, and anodes of the first diode and the second diode are respectively connected to the controlled end of the current spreading circuit; and the cathodes of the first diode and the second diode are connected with a first driving signal output end of the LED driver.
Optionally, the projector further includes a Bp LED lamp, and one of the two output ends of the current spreading circuit is further connected to an electrode of the Bp LED lamp; one of the two output ends of the switch control circuit is also connected with the other end of the Bp LED lamp.
Optionally, the current spreading circuit includes a first current spreading branch and a second current spreading branch;
the two output ends of the first current expansion branch are respectively connected with blue LED lamps and green LED lamps in red, green and blue LED lamps in a one-to-one correspondence manner;
the switch control circuit comprises a first switch control branch and a second switch control branch; the first switch control branch comprises a first electronic switch and a second electronic switch, and the first electronic switch and the second electronic switch are respectively connected with blue LED lamps and green LED lamps in red, green and blue LED lamps in a one-to-one correspondence manner;
the output end of the second current expanding branch circuit is connected with one electrode of a red LED lamp in the red, green and blue LED lamps, and the output end of the second switch control branch circuit is connected with the other electrode of the red LED lamp in the red, green and blue LED lamps.
Optionally, the projector further includes a Bp LED lamp, and one of the two output ends of the first current spreading branch is further connected to an electrode of the Bp LED lamp; one of the two output ends of the first switch control branch is also connected with the other end of the Bp LED lamp.
Optionally, the LED driving circuit further includes a third diode, a fourth diode, and a fifth diode, and anodes of the third diode and the fourth diode are respectively connected to the controlled end of the first current spreading branch; cathodes of the third diode and the fourth diode are connected with a first driving signal output end of the LED driver;
and the anode of the fifth diode is connected with the controlled end of the second current spreading branch, and the cathode of the fifth diode is connected with the second driving signal output end of the LED driver.
Optionally, the LED driving circuit further includes an LED controller, and an output end of the LED controller is connected to the LED driver; the LED controller is configured to output a corresponding LED control signal to the LED driver according to the received image data.
The invention also provides a projector which comprises the LED driving circuit.
The LED driving circuit is configured to output an LED driving signal through an LED lamp LED driver; and the current expansion circuit and the switch control circuit are respectively connected with two electrodes of the LED lamp and are controlled based on LED drive, and the current expansion circuit and the switch control circuit work when receiving an LED drive signal to light the LED lamp. The invention can improve the LED driving current without changing the program and the output of the LED driver under the original driving framework, and the current value can be set at will. Meanwhile, the circuit can ensure the synchronism of the LED switch, and the operation stability of the system is ensured.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
FIG. 1 is a functional block diagram of an LED driving circuit according to an embodiment of the present invention;
fig. 2 is a schematic circuit diagram of an LED driving circuit according to an embodiment of the invention;
FIG. 3 is a schematic circuit diagram of an LED driving circuit according to another embodiment of the present invention;
fig. 4 is a schematic circuit diagram of an LED driving circuit according to another embodiment of the present invention.
The reference numbers illustrate:
the implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.
In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
The invention provides an LED driving circuit which is suitable for various LED light source devices.
Among them, the LED Light source device may be a projector, such as a DLP (Digital Light Processing), which is a device composed of a high-speed Digital Light reflecting switch array based on semiconductor manufacturing technology. The DMD can precisely control the gray scale of light by adopting a binary pulse width modulation technology, and a DLP system is formed by image processing, a memory, a light source and an optical system, so that a large-screen, high-brightness, seamless and high-contrast color image can be projected. The image signal is usually processed digitally and then the light is projected. The optical engine is one of the most important components in DLP projection systems. The following embodiments are described by taking an example of an LED driving circuit applied to a projector, and the LED driving circuit of the present invention is specifically applied to driving red, green and blue LEDs of a projector. DLP projection systems are generally composed of four parts, a light emitting part, a DMD, an optical element, and a structural part. The quality of the light source system directly affects the projection quality of the picture, and with the development of semiconductor technology, the LED becomes an important light source. With the continuous update of projection technology, the micro projector of the DLP projection mode proposed by TI, the DLP projector is increasingly popular with users as a product of TI companies. The volume, brightness, resolution and contrast are all better than those of the early white light LED LCOS technology projector, and the driving scheme is the simplest and the high efficiency only by adopting a TI driving chip set. However, in actual use, the driving current is continuously increased due to the continuously increased brightness requirement of the LED, and the driving range of the LED driving chip provided by the TI is limited, so that the requirement of increasing the driving current of the LED again under the existing driving current of the DLP projector cannot be met.
Referring to fig. 1 to 4, in an embodiment of the present invention, the LED driving circuit includes:
an
the controlled end of the current expanding
the controlled end of the
In this embodiment, the LED driving circuit further includes an
The
The
It is understood that the current expanding
Specifically, when receiving a low-level LED driving signal output from the
The driving current of the red LED lamp LD1 is different from the driving currents of the blue LED lamp LD2 and the green LED lamp LD3 according to the characteristics of the red, green and blue LED lamps themselves, and the driving current of the red LED lamp LD1 is generally smaller than the driving currents of the blue LED lamp LD2 and the green LED lamp LD 3. Therefore, according to the application requirements of the product, for example, in the product with higher brightness requirement, in the application where the brightness of the red, green and blue three-color LED lamps needs to be improved, the current expanding
The LED driving circuit of the present invention is configured to output an LED driving signal through an LED
Referring to fig. 1 to 2, in an embodiment, two output ends of the current spreading
the
In an embodiment, the
and a second LED driving signal output end of the
In this embodiment, the current spreading
And outputting a constant-current constant-duty-ratio LED driving signal to the
The LED driving circuit further comprises a first current sampling resistor R4, and the first current sampling resistor R4 is arranged between the red LED lamp LD1 and the ground in series.
VCC is LED driving voltage, IRed is working current when the red LED lamp LD1 is normally lighted; VLED is the operating voltage across the LED, and ILED _ Min is the minimum LED drive current allowed for DLPA3000 operation. In the above embodiment, the LED driving circuit may be applied to an LED light source device with a red LED driving current of 6A or less and blue and green LEDs driving currents of > 6A. Wherein, R4 is the resistance of the first current sampling resistor R4.
Referring to fig. 1 to 3, in an embodiment, the LED driving circuit further includes a first diode D1 and a second diode D2, and anodes of the first diode D1 and the second diode D2 are respectively connected to the controlled terminal of the current spreading
In this embodiment, the first diode D1 and the second diode D2 form an or logic gate circuit, so as to ensure that the current expanding
Wherein IG and IB are TPS92641 output currents; vref sets the reference voltage for the Iadj pin input current of TPS 92641. R6 is the resistance value of the second current sampling resistor.
Referring to fig. 1 to 3, in an embodiment, the projector further includes a Bp LED lamp LD4, and one of two output terminals of the current spreading
It can be understood that, in order to increase the brightness of the green LED lamp LD3, a Bp LED lamp LD4 is further connected in series in the loop of the green LED lamp LD3, and the Bp LED lamp LD4 is turned on together with the green LED lamp LD3, that is, when the
Referring to fig. 1 to 4, in an embodiment, the current spreading
the two output ends of the first current spreading
the
the output end of the second current expanding
In this embodiment, the current spreading
And outputting a constant-current constant-duty-ratio LED driving signal to the
Referring to fig. 1 to 4, in an embodiment, the projector further includes a Bp LED lamp LD4, and one of two output ends of the first current spreading
It can be understood that, in order to increase the brightness of the green LED lamp LD3, a Bp LED lamp LD4 is further disposed in series in the loop of the green LED lamp LD3, and the Bp LED lamp LD4 is lit along with the green LED lamp LD3, that is, when the
Referring to fig. 1 to 4, in an embodiment, the LED driving circuit further includes a third diode D3, a fourth diode D4, and a fifth diode D5, anodes of the third diode D3 and the fourth diode D4 are respectively connected to the controlled end of the first current spreading
an anode of the fifth diode D5 is connected to the controlled terminal of the second current spreading
In this embodiment, the third diode D3 and the fourth diode D4 form an or logic gate circuit, so as to ensure that the current expanding
The LED driving circuit further comprises a third current sampling resistor R7 and a fourth current sampling resistor R8, and the third current sampling resistor R7 is arranged between a blue LED lamp LD2 and a green LED lamp LD3 in the red, green and blue three-color LED lamp and the ground in series. The fourth current sampling resistor R8 is serially connected between the red LED lamp LD1 of the red, green and blue LED lamps and ground Iadj as a current setting reference voltage input terminal.
Wherein, IR, IG and IB are TPS92641 output currents; vref sets the reference voltage for the Iadj pin input current of TPS 92641. R7 is the resistance value of the third sampling resistor, and R8 is the resistance value of the fourth sampling resistor. In the above embodiment, the LED driving circuit may be applied to an LED light source device in which the driving current of the red LED is > 6A and the driving currents of the blue LED and the green LED are > 6A. The LED driving circuit can be applied to DLP projection systems and laser projection systems, in particular to projection systems with high-brightness LEDs as light sources. The LED drive circuit can conveniently improve the LED drive current on the basis of the original TI scheme, and the current value can be set at will. Meanwhile, the circuit can ensure the synchronism of the LED switch, and the operation stability of the system is ensured. The original framework is not required to be changed, the development time and difficulty of the circuit can be effectively reduced, and the LED driving circuit is favorable for popularization and application in high-current products.
The invention also provides a projector which comprises the LED driving circuit. The detailed structure of the LED driving circuit can refer to the above embodiments, and is not described herein; it can be understood that, because the LED driving circuit is used in the projector of the present invention, the embodiment of the projector of the present invention includes all technical solutions of all embodiments of the LED driving circuit, and the achieved technical effects are also completely the same, and are not described herein again.
The above description is only an alternative embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.
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