CN112020175A - LED dimming circuit and device - Google Patents
LED dimming circuit and device Download PDFInfo
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- CN112020175A CN112020175A CN201910396080.XA CN201910396080A CN112020175A CN 112020175 A CN112020175 A CN 112020175A CN 201910396080 A CN201910396080 A CN 201910396080A CN 112020175 A CN112020175 A CN 112020175A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
Abstract
The invention discloses an LED dimming circuit and LED dimming equipment. The invention comprises a dimming circuit and a driving circuit; the dimming circuit is connected with the control circuit and the drive circuit respectively and used for receiving the PWM signal sent by the control circuit, converting the PWM signal into a direct current signal and outputting the direct current signal to the drive circuit; the driving circuit comprises an active driving unit and a passive driving unit, the active driving unit and the passive driving unit are connected with a power supply of the control circuit and an LED driving dimming end respectively after being connected in parallel, and the control circuit is used for normally driving the LED driving power supply to dim light according to the direct current signal when the LED driving dimming end is in active output or passive output, or the control circuit is in fault state to disconnect the dimming circuit and the LED driving dimming end, so that the dimming circuit is prevented from reducing the output of the LED driving dimming end, the full-power output of the LED driving power supply is ensured, and the influence on illumination caused by the fact that a lamp cannot reach 100% brightness is avoided.
Description
Technical Field
The invention relates to the technical field of lighting, in particular to an LED dimming circuit and LED dimming equipment.
Background
With the popularization of LED lighting and the development of LED intelligent dimming control technology, various dimming technologies, such as 0-10V dimming or PWM (Pulse Width Modulation) dimming, appear on the market, and these dimming technologies are generally applied to environments such as municipal lighting or road traffic lighting, and ensure the road surface illumination requirement and traffic safety.
The most common dimming circuit at present is: the control circuit outputs an adjustable PWM signal, the weak PWM signal is converted into a 1-10V dimming signal for controlling the LED to drive the dimming end through the amplifying circuit, and the 10-100% brightness of the lamp is adjusted.
The existing dimming circuit has the main defects that the brightness of a lamp can be adjusted by 10-100% under the condition of normal work, but when the control circuit fails, the output end of the dimming circuit is in a low-resistance state, so that a 10V signal on the dimming end driven by an LED is pulled down, the lamp cannot reach 100% brightness, and the traffic safety is affected seriously.
Disclosure of Invention
The invention mainly aims to provide an LED dimming circuit and LED dimming equipment, and aims to solve the technical problem that an LED driving power supply cannot output full power due to control circuit faults in the prior art.
In order to achieve the above object, the present invention provides an LED dimming circuit, which includes a dimming circuit and a driving circuit; wherein the content of the first and second substances,
the dimming circuit is respectively connected with the control circuit and the driving circuit and is used for receiving the PWM signal sent by the control circuit, converting the PWM signal into a direct current signal and outputting the direct current signal to the driving circuit;
the driving circuit comprises an active driving unit and a passive driving unit; the input end of the active driving unit is connected with the output end of the passive driving unit, the output end of the active driving unit is connected with the input end of the passive driving unit, the output end of the active driving unit is respectively connected with the driving circuit and the power supply of the control circuit, the input end of the passive driving unit is respectively connected with the driving circuit and the power supply, and the input end of the active driving unit and the output end of the passive driving unit are respectively connected with the LED driving dimming end;
the active driving unit is used for enabling the control circuit to be normal when the LED driving dimming end is in active output, enabling the direct current signal to absorb an injection current signal of the LED driving dimming end through the active driving unit and then adjust the LED brightness, or enabling the control circuit to be in fault, and disconnecting the dimming circuit from the LED driving dimming end so as to enable the LED driving dimming end to be suspended and guarantee full-power output of the LED driving power supply;
the passive driving unit is used for driving the dimming end of the LED to output passively, the control circuit is normal, the direct current signal passes through the passive driving unit to drive the dimming end of the LED to perform dimming, or the control circuit fails and disconnects the dimming circuit from the dimming end of the LED to enable the dimming end of the LED to be suspended, and therefore full-power output of the LED driving power supply is guaranteed.
Preferably, the passive driving unit includes a first resistor, a second resistor, a third resistor, a first triode, a second triode and a first diode; wherein the content of the first and second substances,
an emitting electrode of the second triode is connected with an output end of the dimming circuit, a base electrode of the second triode is respectively connected with a collector electrode of the first triode and a first end of the first resistor, and a collector electrode of the second triode is connected with an anode of the first diode;
the cathode of the first diode is connected with the LED driving dimming end;
the second end of the first resistor is connected with the power supply;
the first end of the second resistor is connected with the power supply, and the second end of the second resistor is respectively connected with the first end of the third resistor and the base electrode of the first triode;
the emitting electrode of the first triode is grounded;
and the second end of the third resistor is grounded.
Preferably, the active driving unit includes a fourth resistor, a fifth resistor, a sixth resistor, a third transistor, a fourth transistor, and a second diode; wherein the content of the first and second substances,
the cathode of the second diode is connected with the output end of the dimming circuit, and the anode of the second diode is connected with the collector of the third triode;
an emitting electrode of the third triode is connected with the LED driving dimming end, and a base electrode of the third triode is respectively connected with a first end of the fourth resistor and a collector electrode of the fourth triode;
the second end of the fourth resistor is connected with the power supply and the first end of the fifth resistor respectively;
a base electrode of the fourth triode is connected with the second end of the fifth resistor and the first end of the sixth resistor respectively, and an emitting electrode of the fourth triode is grounded;
and the second end of the sixth resistor is grounded.
Preferably, the first triode and the fourth triode are NPN triodes or NMOS transistors, and the second triode and the third triode are PNP triodes or PMOS transistors.
Preferably, the dimming circuit includes a filtering unit and an amplifying unit; the filtering unit is connected with the control circuit and the amplifying unit respectively, and the amplifying unit is connected with the driving circuit.
Preferably, the filtering unit includes a first capacitor and a seventh resistor; the first end of the seventh resistor is connected with the control circuit, the second end of the seventh resistor is grounded through the first capacitor, and the second end of the seventh resistor is also connected with the amplifying unit.
Preferably, the amplifying unit includes a comparison amplifier, an eighth resistor, and a ninth resistor; wherein the content of the first and second substances,
the non-inverting input end of the comparison amplifier is connected with the second end of the seventh resistor, the inverting input end of the comparison amplifier is respectively connected with the first end of the eighth resistor and the first end of the ninth resistor, and the output end of the comparison amplifier is respectively connected with the second end of the ninth resistor and the driving circuit;
and the second end of the eighth resistor is grounded.
Preferably, the LED driving circuit further comprises a second capacitor, a first end of the second capacitor is connected to the driving circuit and the LED driving dimming end, and a second end of the second capacitor is grounded and used for filtering an output signal of the driving circuit and outputting the filtered output signal to the LED driving dimming end.
The invention also provides LED dimming equipment which comprises the LED dimming circuit.
The dimming circuit is respectively connected with the control circuit and the drive circuit and is used for receiving the PWM signal sent by the control circuit, converting the PWM signal into a direct current signal and outputting the direct current signal to the drive circuit; the driving circuit comprises an active driving unit and a passive driving unit, the active driving unit and the passive driving unit are connected in parallel and then are respectively connected with a power supply of the control circuit and an LED driving dimming end, the LED driving dimming end is used for adjusting the LED brightness when the LED driving dimming end is in active output or passive output, meanwhile, the LED driving dimming end is protected from being damaged or does not work, the LED driving power supply is driven to dim light by the control circuit normally according to the direct current signal, or the dimming circuit is disconnected with the LED driving dimming end due to the control circuit fault, the dimming circuit is prevented from reducing the output of the LED driving dimming end, the full-power output of the LED driving power supply is guaranteed, and the influence on illumination caused by the fact that a lamp cannot reach 100% brightness is avoided.
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 embodiment of an LED dimming circuit according to the present invention;
fig. 2 is a schematic structural diagram of an embodiment of an LED dimming circuit according to the present invention.
The reference numbers illustrate:
| reference numerals | Name (R) | Reference numerals | Name (R) |
| 100 | Light modulation circuit | R1～R9 | First to |
| 200 | Driving circuit | C1～C2 | First to |
| 210 | Passive drive unit | Q1～Q4 | First to |
| 220 | Active drive unit | D1～D2 | First to second diodes |
| PWM IN | Control circuit | U1 | Comparison amplifier |
| VCC | Power supply | GND | Ground connection |
| OUT | LED driving dimming end |
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 dimming circuit.
Referring to fig. 1, in an embodiment, the circuit includes a dimming circuit 100 and a driving circuit 200; the dimming circuit 100 is connected to the control circuit PWM IN and the driving circuit 200, and configured to receive a PWM signal sent by the control circuit PWM IN, convert the PWM signal into a dc signal, and output the dc signal to the driving circuit 200; the driving circuit 200 includes an active driving unit 220 and a passive driving unit 210; the input end of the active driving unit 220 is connected to the output end of the passive driving unit 210, the output end of the active driving unit 220 is connected to the input end of the passive driving unit 210, the output end of the active driving unit 220 is connected to the driving circuit 200 and the power supply VCC of the control circuit PWM IN, the input end of the passive driving unit 210 is connected to the driving circuit 200 and the power supply VCC, and the input end of the active driving unit 220 and the output end of the passive driving unit 210 are connected to the LED driving dimming end OUT; the active driving unit 220 is configured to, when the LED driving dimming end is IN active output, enable the control circuit PWM IN to be normal, enable the direct current signal to absorb an injection current signal of the LED driving dimming end OUT through the active driving unit 220 to adjust the LED brightness, or enable the control circuit PWM IN to have a fault, disconnect the dimming circuit 100 from the LED driving dimming end OUT, so that the LED driving dimming end is suspended, and ensure full power output of the LED driving power supply; the passive driving unit 210 is configured to, when the LED driving dimming end is IN passive output, control circuit PWM IN is normal, the direct current signal drives the LED driving dimming end OUT to dim light through the passive driving unit 210, or the control circuit PWM IN fails, and disconnects the dimming circuit 100 from the LED driving dimming end OUT, so that the LED driving dimming end is suspended, and full-power output of the LED driving power supply is ensured.
It is easy to understand that, when the LED driving dimming terminal OUT is an active output, the LED driving dimming terminal OUT outputs a 10V dimming signal by default, and the dimming circuit 100 pulls down the current of the 10V dimming signal to achieve the purpose of dimming. When the LED driving dimming terminal OUT is in a passive output state, the dimming circuit 100 outputs a dimming signal of 1-10V to drive the LED driving dimming terminal OUT to dim.
It should be noted that the control circuit PWM IN includes a controller and related circuits, which is not limited IN this embodiment, and the power supply VCC is a power supply of the control circuit PWM IN, and is usually 15V to 25V.
IN the prior art, when the control circuit is normal, the comparison amplifier directly drives the LED driving dimming end to dim light, and when the control circuit fails, the comparison amplifier pulls down the output signal of the LED driving dimming end, so that the lamp cannot output 100%, IN this embodiment, the driving circuit 200 is added, when the control circuit PWM IN fails or does not work, the dimming circuit 100 and the LED driving dimming end OUT are IN an open circuit state, and the dimming circuit 100 does not affect the output signal of the LED driving dimming end OUT, so that the lamp 100% output is ensured.
In a specific implementation, the driving circuit 200 of the present embodiment includes an active driving unit 220 and a passive driving unit 210, so as to be compatible with two cases, namely active output and passive output, of the LED driving dimming terminal OUT. Of course, in this embodiment, the driving circuit 200 may also include only the active driving unit 220 or only the passive driving unit 210, and when only the active driving unit 220 is included, only the case where the LED driving dimming terminal OUT is active output is compatible, and when only the passive driving unit 210 is included, only the case where the LED driving dimming terminal OUT is passive output is compatible.
The dimming circuit is connected with the control circuit and the driving circuit respectively and used for receiving the PWM signal sent by the control circuit, converting the PWM signal into a direct current signal and outputting the direct current signal to the driving circuit; the driving circuit comprises an active driving unit and a passive driving unit, the active driving unit and the passive driving unit are connected in parallel and then are respectively connected with a power supply of the control circuit and an LED driving dimming end, the LED driving dimming end is used for adjusting the LED brightness when the LED driving dimming end is in active output or passive output, meanwhile, the LED driving dimming end is protected from being damaged or does not work, the LED driving power supply is driven to dim light by the control circuit normally according to the direct current signal, or the dimming circuit is disconnected with the LED driving dimming end due to the control circuit fault, the dimming circuit is prevented from reducing the output of the LED driving dimming end, the full-power output of the LED driving power supply is guaranteed, and the influence on illumination caused by the fact that a lamp cannot reach 100% brightness is avoided.
Referring to fig. 2, further, the passive driving unit 210 includes a first resistor R1, a second resistor R2, a third resistor R3, a first transistor Q1, a second transistor Q2, and a first diode D1; an emitter of the second transistor Q2 is connected to an output terminal of the dimming circuit 100, a base of the second transistor Q2 is connected to a collector of the first transistor Q1 and a first end of the first resistor R1, respectively, and a collector of the second transistor Q2 is connected to an anode of the first diode D1; the cathode of the first diode D1 is connected with the LED driving dimming end OUT; a second end of the first resistor R1 is connected to the power supply VCC; a first end of the second resistor R2 is connected to the power supply VCC, and a second end of the second resistor R2 is connected to a first end of the third resistor R3 and a base of the first transistor Q1, respectively; the emitter of the first triode Q1 is grounded; the second end of the third resistor R3 is grounded.
It should be noted that, when the LED driving dimming end OUT is a passive output, if the control circuit PWM IN is normal, the control circuit PWM IN outputs a 0-5V PWM signal, the PWM signal is converted into a 0-11V dc signal by the dimming circuit 100, and meanwhile, the power supply VCC is normally powered, the first triode Q1 is turned on, the base of the second triode Q2 is at a low level, the second triode Q2 satisfies the conduction condition, the first diode D1 is turned on, the 0-11V dc signal is reduced to a 1-10V dimming signal after passing through the second triode Q2 and the first diode D1 (the voltage drop of the triode is about 0.3V when the triode is normally turned on, and the voltage drop of the diode is about 0.7V when the diode is normally turned on), and the LED driving power supply is driven to adjust the LED power to change from 10% to 100%.
If the control circuit PWM IN fails or does not work, the control circuit PWM IN does not output a PWM signal, and meanwhile, the power supply VCC cannot normally supply power, the base of the first triode Q1 is at a low level, the first triode Q1 is cut off, the second triode Q2 is cut off, the first diode D1 is cut off, the dimming circuit 100 and the LED driving dimming end OUT are IN an open circuit state, so as to ensure that the LED driving dimming end OUT is not affected by the low resistance of the comparison amplifier U1, and the LED driving power supply outputs full power.
In a specific implementation, the first triode is an NPN triode or an NMOS transistor, and the second triode is a PNP triode or a PMOS transistor, which is not limited in this embodiment.
Further, the active driving unit 220 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a third transistor Q3, a fourth transistor Q4, and a second diode D2; wherein a cathode of the second diode D2 is connected to the output terminal of the dimming circuit 100, and an anode of the second diode D2 is connected to a collector of the third transistor Q3; an emitter of the third transistor Q3 is connected to the LED driving dimming terminal OUT, and a base of the third transistor Q3 is connected to a first terminal of the fourth resistor R4 and a collector of the fourth transistor Q4, respectively; a second end of the fourth resistor R4 is connected to the power supply VCC and a first end of the fifth resistor R5, respectively; a base of the fourth transistor Q4 is connected to the second end of the fifth resistor R5 and the first end of the sixth resistor R6, respectively, and an emitter of the fourth transistor Q4 is grounded; a second terminal of the sixth resistor R6 is connected to ground.
It should be noted that, in the main circuit formed by the active driving unit 220, the dimming circuit 100 and the LED driving dimming end OUT, the active driving unit 220 only has the third transistor Q3 and the second diode D2, and no resistor is used, because when the LED driving dimming end OUT is an active output, a current is injected into the driving circuit 200, and if a resistor is used in the main circuit, the current limiting due to the resistor affects the ability of absorbing the injected current, thereby causing the driving ability of the driving circuit 200 to be weakened.
It can be understood that when the LED driving dimming end OUT is an active output, if the control circuit PWM IN is normal, the LED driving dimming end OUT is driven to output a 10V signal by default, the control circuit PWM IN outputs a 0-5V PWM signal, the PWM signal is converted into a 0-11V dc signal by the dimming circuit 100, and when the dimming circuit 100 outputs an 11V dc signal, the LED driving power supply can be driven to output full power because the voltage is higher than 10V output by the LED driving dimming end OUT; when the comparison amplifier U1 outputs a 0-10V dc signal, the third transistor Q3 is turned on and the second diode D2 is turned on due to a voltage difference, and the dc current forms a loop through the dimming circuit 100 to change the signal of the LED driving dimming terminal OUT10V with the change of 0-10V at the output terminal of the driving circuit 200, so as to drive the LED driving power supply to adjust the power of the LED from 10% to 100%.
If the control circuit PWM IN fails or does not work, the control circuit PWM IN does not output a PWM signal, and meanwhile, the power supply VCC cannot normally supply power, the base of the fourth triode Q4 is at a low level, the fourth triode Q4 is cut off, the third triode Q3 is cut off, the second diode D2 is cut off, the dimming circuit 100 and the LED driving dimming end OUT are IN an open circuit state, so as to ensure that the LED driving dimming end OUT is not affected by the low resistance of the comparison amplifier U1, and the LED driving power supply outputs full power.
In a specific implementation, the fourth triode is an NPN triode or an NMOS transistor, and the third triode is a PNP triode or a PMOS transistor, which is not limited in this embodiment.
Further, the dimming circuit 100 includes a filtering unit 110 and an amplifying unit 120; the filtering unit 110 is connected to the control circuit PWM IN and the amplifying unit 120, respectively, and the amplifying unit 120 is connected to the driving circuit 200.
It is understood that the filtering unit 110 is configured to filter the PWM signal output by the control circuit PWM IN and output a dc signal of 0-5V, and the amplifying unit 120 is configured to amplify the dc signal of 0-5V into a dc signal of 0-11V.
Further, the filter unit 110 includes a first capacitor C1 and a seventh resistor R7; a first terminal of the seventh resistor R7 is connected to the control circuit PWM IN, a second terminal of the seventh resistor R7 is connected to the ground via the first capacitor C1, and a second terminal of the seventh resistor R7 is further connected to the amplifying unit 120.
Further, the amplifying unit 120 includes a comparison amplifier U1, an eighth resistor R8, and a ninth resistor R9; a non-inverting input terminal of the comparison amplifier U1 is connected to the second terminal of the seventh resistor R7, an inverting input terminal of the comparison amplifier U1 is connected to the first terminal of the eighth resistor R8 and the first terminal of the ninth resistor R9, respectively, and an output terminal of the comparison amplifier U1 is connected to the second terminal of the ninth resistor R9 and the driving circuit 200, respectively; a second terminal of the eighth resistor R8 is connected to ground.
It should be noted that the eighth resistor R8 and the ninth resistor R9 are adjustable resistors, and the output voltage of the comparator amplifier U1 can be controlled by adjusting the resistance values of the eighth resistor R8 and the ninth resistor R9, in this embodiment, in order to output the 1-10V dimming signal, the PWM signal of 0-5V needs to be amplified to be a dc signal of 0-11V.
Further, the LED dimming circuit further includes a second capacitor C2, a first end of the second capacitor C2 is connected to the driving circuit 200 and the LED driving dimming end OUT, respectively, and a second end of the second capacitor C2 is grounded, and is configured to filter an output signal of the driving circuit 200 and output the filtered output signal to the LED driving dimming end OUT.
It should be understood that the second capacitor C2 is a filter capacitor for filtering the signal output by the driving circuit 200 to filter out the interference signal, so as to obtain a more stable dimming signal.
The working principle of the present embodiment is explained below with reference to fig. 2:
when the LED driving dimming end OUT is a passive output, if the control circuit PWM IN is normal, the control circuit PWM IN outputs a 0-5V PWM signal, the PWM signal is filtered by the filtering unit 110 and converted into a 0-5V dc signal, and then amplified by the amplifying unit 120 to a 0-11V dc signal, meanwhile, the power supply VCC of the control circuit PWM IN is normally powered, the first triode Q1 is turned on, the base of the second triode Q2 is at a low level, the second triode Q2 meets the conduction condition, the first diode D1 is turned on, the 0-11V dc signal is stepped down to a 1-10V dimming signal after passing through the second triode Q2 and the first diode D1, and the LED driving power supply is driven to adjust the LED power from 10% to 100%.
If the control circuit PWM IN fails or does not work, the control circuit PWM IN does not output a PWM signal, the comparison amplifier U1 IN the amplifying unit 120 is IN a low-resistance state, and meanwhile, the power supply VCC cannot normally supply power, the base of the first triode Q1 is at a low level, the first triode Q1 is cut off, the second triode Q2 is cut off, the first diode D1 is cut off, the dimming circuit 100 and the LED driving dimming end OUT are IN an open-circuit state, it is ensured that the LED driving dimming end OUT is not affected by the low resistance of the comparison amplifier U1, and the LED driving power supply outputs full power.
When the LED driving dimming end OUT is IN active output, if the control circuit PWM IN is normal, the LED driving dimming end OUT is driven to output a 10V signal by default, the control circuit PWM IN outputs a 0-5V PWM signal, the PWM signal is filtered by the filtering unit 110 and converted into a 0-5V direct current signal, and then the 0-5V direct current signal is amplified by the amplifying unit 120 to be a 0-11V direct current signal, and when the comparison amplifier U1 outputs an 11V direct current signal, the LED driving power supply can be driven to output full power because the voltage is higher than 10V output by the LED driving dimming end OUT; when the comparison amplifier U1 outputs a 0-10V direct current signal, the third triode Q3 is turned on due to a voltage difference, the second diode D2 is turned on, and the direct current forms a loop through the comparison amplifier U1 so that the signal of the LED driving dimming end OUT10V changes along with the change of 0-10V of the output end of the driving circuit 200, and the LED driving power supply is driven to adjust the LED power from 10% -100%.
If the control circuit PWM IN fails or does not work, the control circuit PWM IN does not output the PWM signal, the comparison amplifier U1 IN the amplifying unit 120 is IN a low-resistance state, and meanwhile, the power supply VCC cannot normally supply power, the base of the fourth triode Q4 is at a low level, the fourth triode Q4 is cut off, the third triode Q3 is cut off, the second diode D2 is cut off, the dimming circuit 100 and the LED driving dimming end OUT are IN an open-circuit state, it is ensured that the LED driving dimming end OUT is not affected by the low resistance of the comparison amplifier U1, and the LED driving power supply outputs full power.
According to the LED driving power supply dimming control circuit, through the specific circuit design of the dimming circuit, the active driving unit and the passive driving unit, when the LED driving dimming end is in active output or passive output, the control circuit normally drives the LED driving power supply to dim light according to the direct current signal, or the control circuit is in fault, the dimming circuit is disconnected with the LED driving dimming end, the dimming circuit is prevented from reducing the output of the LED driving dimming end, the full-power output of the LED driving power supply is ensured, and the illumination is prevented from being influenced due to the fact that a lamp cannot reach 100% of brightness.
The invention also provides an LED dimming device, which comprises the LED dimming circuit, wherein the circuit structure of the LED dimming circuit of the LED dimming device can refer to the embodiment and is not described herein again; it can be understood that, since the LED dimming device of the present embodiment adopts the above-mentioned technical solution of the LED dimming circuit, the LED dimming device has all the above-mentioned advantages.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (9)
1. An LED dimming circuit is characterized by comprising a dimming circuit and a driving circuit; wherein the content of the first and second substances,
the dimming circuit is respectively connected with the control circuit and the driving circuit and is used for receiving the PWM signal sent by the control circuit, converting the PWM signal into a direct current signal and outputting the direct current signal to the driving circuit;
the driving circuit comprises an active driving unit and a passive driving unit; the input end of the active driving unit is connected with the output end of the passive driving unit, the output end of the active driving unit is connected with the input end of the passive driving unit, the output end of the active driving unit is respectively connected with the driving circuit and the power supply of the control circuit, the input end of the passive driving unit is respectively connected with the driving circuit and the power supply, and the input end of the active driving unit and the output end of the passive driving unit are respectively connected with the LED driving dimming end;
the active driving unit is used for enabling the control circuit to be normal when the LED driving dimming end is in active output, enabling the direct current signal to absorb an injection current signal of the LED driving dimming end through the active driving unit and then adjust the LED brightness, or enabling the control circuit to be in fault, and disconnecting the dimming circuit from the LED driving dimming end so as to enable the LED driving dimming end to be suspended and guarantee full-power output of the LED driving power supply;
the passive driving unit is used for driving the dimming end of the LED to output passively, the control circuit is normal, the direct current signal passes through the passive driving unit to drive the LED driving power supply to dim light, or the control circuit is in failure and disconnects the dimming circuit and the dimming end of the LED driving power supply, so that the dimming end of the LED driving power supply is suspended, and the full-power output of the LED driving power supply is ensured.
2. The LED dimming circuit of claim 1, wherein the passive drive unit comprises a first resistor, a second resistor, a third resistor, a first transistor, a second transistor, and a first diode; wherein the content of the first and second substances,
an emitting electrode of the second triode is connected with an output end of the dimming circuit, a base electrode of the second triode is respectively connected with a collector electrode of the first triode and a first end of the first resistor, and a collector electrode of the second triode is connected with an anode of the first diode;
the cathode of the first diode is connected with the LED driving dimming end;
the second end of the first resistor is connected with the power supply;
the first end of the second resistor is connected with the power supply, and the second end of the second resistor is respectively connected with the first end of the third resistor and the base electrode of the first triode;
the emitting electrode of the first triode is grounded;
and the second end of the third resistor is grounded.
3. The LED dimming circuit of claim 2, wherein the active drive unit comprises a fourth resistor, a fifth resistor, a sixth resistor, a third transistor, a fourth transistor, and a second diode; wherein the content of the first and second substances,
the cathode of the second diode is connected with the output end of the dimming circuit, and the anode of the second diode is connected with the collector of the third triode;
an emitting electrode of the third triode is connected with the LED driving dimming end, and a base electrode of the third triode is respectively connected with a first end of the fourth resistor and a collector electrode of the fourth triode;
the second end of the fourth resistor is connected with the power supply and the first end of the fifth resistor respectively;
a base electrode of the fourth triode is connected with the second end of the fifth resistor and the first end of the sixth resistor respectively, and an emitting electrode of the fourth triode is grounded;
and the second end of the sixth resistor is grounded.
4. The LED dimming circuit of claim 3, wherein the first transistor and the fourth transistor are NPN transistors or NMOS transistors, and the second transistor and the third transistor are PNP transistors or PMOS transistors.
5. The LED dimming circuit according to any one of claims 1 to 4, wherein the dimming circuit comprises a filtering unit and an amplifying unit; the filtering unit is connected with the control circuit and the amplifying unit respectively, and the amplifying unit is connected with the driving circuit.
6. The LED dimming circuit of claim 5, wherein the filtering unit comprises a first capacitor and a seventh resistor; the first end of the seventh resistor is connected with the control circuit, the second end of the seventh resistor is grounded through the first capacitor, and the second end of the seventh resistor is also connected with the amplifying unit.
7. The LED dimming circuit of claim 6, wherein the amplifying unit comprises a comparison amplifier, an eighth resistor and a ninth resistor; wherein the content of the first and second substances,
the non-inverting input end of the comparison amplifier is connected with the second end of the seventh resistor, the inverting input end of the comparison amplifier is respectively connected with the first end of the eighth resistor and the first end of the ninth resistor, and the output end of the comparison amplifier is respectively connected with the second end of the ninth resistor and the driving circuit;
and the second end of the eighth resistor is grounded.
8. The LED dimming circuit of claim 7, further comprising a second capacitor, wherein a first end of the second capacitor is connected to the driving circuit and the LED driving dimming end, respectively, and a second end of the second capacitor is grounded, and is configured to filter an output signal of the driving circuit and output the filtered output signal to the LED driving dimming end.
9. LED dimming device, comprising a LED dimming circuit according to any of claims 1-8.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910396080.XA CN112020175A (en) | 2019-05-13 | 2019-05-13 | LED dimming circuit and device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910396080.XA CN112020175A (en) | 2019-05-13 | 2019-05-13 | LED dimming circuit and device |
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| CN112020175A true CN112020175A (en) | 2020-12-01 |
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| US20140176016A1 (en) * | 2012-12-17 | 2014-06-26 | Ecosense Lighting Inc. | Systems and methods for dimming of a light source |
| CN105025636A (en) * | 2015-07-31 | 2015-11-04 | 广东南能汇智节能科技有限公司 | Light-emitting diode (LED) dimming circuit |
| CN205160843U (en) * | 2015-08-31 | 2016-04-13 | 鑫谷光电股份有限公司 | Turn over to swash formula LED drive circuit that adjusts luminance |
| WO2018157345A1 (en) * | 2017-03-02 | 2018-09-07 | 深圳市豪恩光电照明股份有限公司 | Led lamp and led brightness regulation circuit |
| CN209914140U (en) * | 2019-05-13 | 2020-01-07 | 广东芯神科技有限公司 | LED dimming circuit and device |
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2019
- 2019-05-13 CN CN201910396080.XA patent/CN112020175A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140176016A1 (en) * | 2012-12-17 | 2014-06-26 | Ecosense Lighting Inc. | Systems and methods for dimming of a light source |
| CN105025636A (en) * | 2015-07-31 | 2015-11-04 | 广东南能汇智节能科技有限公司 | Light-emitting diode (LED) dimming circuit |
| CN205160843U (en) * | 2015-08-31 | 2016-04-13 | 鑫谷光电股份有限公司 | Turn over to swash formula LED drive circuit that adjusts luminance |
| WO2018157345A1 (en) * | 2017-03-02 | 2018-09-07 | 深圳市豪恩光电照明股份有限公司 | Led lamp and led brightness regulation circuit |
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