CN107734777B - LED driving chip, LED driving circuit and LED lighting device - Google Patents
LED driving chip, LED driving circuit and LED lighting device Download PDFInfo
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- CN107734777B CN107734777B CN201711101077.8A CN201711101077A CN107734777B CN 107734777 B CN107734777 B CN 107734777B CN 201711101077 A CN201711101077 A CN 201711101077A CN 107734777 B CN107734777 B CN 107734777B
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- 230000005669 field effect Effects 0.000 claims abstract description 38
- 239000003990 capacitor Substances 0.000 claims description 36
- 238000012423 maintenance Methods 0.000 claims description 17
- 238000006243 chemical reaction Methods 0.000 claims description 14
- 239000004973 liquid crystal related substance Substances 0.000 claims description 12
- 230000001276 controlling effect Effects 0.000 claims description 7
- 230000001105 regulatory effect Effects 0.000 claims description 2
- 238000002955 isolation Methods 0.000 description 5
- 238000005286 illumination Methods 0.000 description 4
- 230000002093 peripheral effect Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000020169 heat generation Effects 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
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- 229920006395 saturated elastomer Polymers 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/37—Converter circuits
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
Abstract
The invention discloses an LED driving chip, an LED driving circuit and an LED lighting device, wherein the LED driving chip comprises a power input end, a line voltage compensation input end, a current setting end, an over-temperature adjusting module, a band gap reference module, an operational amplifier, a field effect tube, a high-voltage power switching tube and a line voltage compensation module; the field effect transistor steps down the input voltage and outputs the voltage to the band gap reference module to generate corresponding reference voltage; the over-temperature adjusting module detects the temperature of the LED driving chip and outputs a corresponding over-temperature adjusting signal to the band gap reference module so as to adjust the temperature of the LED driving chip; the line voltage compensation module is used for detecting the voltage input by the power input end, and linearly adjusting the reference voltage value output to the operational amplifier according to the voltage input by the power input end so as to compensate the total power of the LED driving chip. The invention solves the problems of unstable power and serious fluctuation of the LED driving chip system.
Description
Technical Field
The invention relates to the technical field of illumination, in particular to an LED driving chip, an LED driving circuit and an LED illumination device.
Background
At present, the LED lamp has the advantages of energy conservation, environmental protection, long service life, small volume and the like, and the LED lamp gradually replaces the traditional light source in the aspects of illumination and the like, becomes a new generation of solid illumination light source, and is also generated and applied along with the linear constant current LED driving chip.
However, when the number of the LED lamp strings is fixed, when the alternating current voltage input by the power input end of the LED driving system is increased, the resistance value of the power tube is increased under the condition that the current of the system is not increased, so that the power consumption of the power tube is increased to generate heat seriously, and once the temperature in the chip is increased to trigger over-temperature adjustment, the total power of the system is firstly increased and then decreased, so that the problems of unstable power and serious fluctuation occur.
Disclosure of Invention
The invention mainly aims to provide an LED driving chip, an LED driving circuit and an LED lighting device, and aims to solve the problems that when the input voltage of an LED driving chip system is increased, the power consumption of a power tube is increased and the heat generation is serious, so that the power is unstable and the fluctuation is serious.
In order to achieve the above object, the present invention provides an LED driving chip, which includes a power input terminal, a line voltage compensation input terminal, a current setting terminal, and an over-temperature adjusting module, a bandgap reference module, an operational amplifier, a field effect transistor, a high voltage power switching tube, and a line voltage compensation module integrated in the LED driving chip, wherein the power input terminal is connected to a drain electrode of the field effect transistor and a drain electrode of the high voltage power switching tube, respectively; the current setting end is respectively connected with the grid electrode of the field effect transistor, the inverting input end of the operational amplifier and the source electrode of the high-voltage power switch tube; the source electrode of the field effect tube and the output end of the over-temperature regulating module are connected with the band gap reference module; the output end of the operational amplifier is connected with the grid electrode of the high-voltage power switch tube; the line voltage compensation input end is connected with the input end of the line voltage compensation module; the output end of the line voltage compensation module and the output end of the band gap reference module are respectively connected with the positive phase output end of the operational amplifier; wherein, the liquid crystal display device comprises a liquid crystal display device,
the field effect transistor is used for reducing the input voltage and outputting the reduced voltage to the band gap reference module to generate corresponding reference voltage;
the over-temperature adjusting module is used for detecting the temperature of the LED driving chip and outputting a corresponding over-temperature adjusting signal to the band gap reference module so as to adjust the temperature of the LED driving chip;
the line voltage compensation module is used for detecting the voltage input by the power input end and linearly adjusting the reference voltage value output to the operational amplifier according to the voltage input by the power input end so as to compensate the total power of the LED driving chip.
Preferably, the LED driving chip further comprises a low-voltage power supply module for supplying power to the operational amplifier, an input end of the low-voltage power supply module is connected with a source electrode of the field effect transistor, and an output end of the low-voltage power supply module is connected with a power supply end of the operational amplifier.
Preferably, the LED driving chip further includes a ground terminal, the line voltage compensation module includes a first MOS transistor, a second MOS transistor, a third MOS transistor, and a fourth MOS transistor, a drain electrode of the first MOS transistor is an input terminal of the line voltage compensation module and is interconnected with a gate electrode, the line voltage compensation input terminal, and the gate electrode of the third MOS transistor, and a source electrode of the first MOS transistor is interconnected with the gate electrode, the drain electrode, and the gate electrode of the second MOS transistor; the drain electrode of the third MOS tube is the output end of the line voltage compensation module, and the source electrode of the third MOS tube is connected with the drain electrode of the fourth MOS tube; the source electrode of the second MOS tube is connected with the source electrode of the fourth MOS tube and the grounding end.
Preferably, the high-voltage power switch tube is an MOS tube.
The invention also provides an LED driving circuit which comprises a power supply conversion circuit, a first LED lamp string, a second LED lamp string, a first chip module, a first current preset resistor, a second current preset resistor, a line voltage compensation maintaining capacitor, a unidirectional conduction element and a plurality of LED driving chips, wherein the LED driving chips are arranged in parallel; the input end of the power supply conversion circuit is used for accessing alternating voltage, and the output end of the power supply conversion circuit is respectively connected with a plurality of power supply input ends of the first chip module and the input end of the first LED lamp string; the output end of the first LED lamp string is connected with the input end of the unidirectional conduction element; the current setting ends of the first chip module are respectively connected with the output end of the unidirectional conduction element and the first end of the first current preset resistor; the grounding ends of the first chip module are respectively connected with the second end of the first current preset resistor and the input end of the second LED lamp string; the output end of the second LED lamp string is connected with the power input ends of the plurality of LED driving chips and the first ends of the line voltage compensation preset resistors; the second end of the line voltage compensation preset resistor is connected with the line voltage compensation input ends of the LED driving chips and the first ends of the line voltage compensation maintaining capacitors; the second end of the line voltage compensation maintaining capacitor, the grounding ends of the LED driving chips and the first ends of the second current preset resistors are grounded; and the current setting ends of the LED driving chips are connected with the second ends of the second current preset resistors.
Preferably, the first chip module comprises a plurality of first chips, the first chips comprise a first power input end, a first line voltage compensation input end, a first current setting end, and a first over-temperature adjusting module, a first bandgap reference module, a first operational amplifier, a first field effect transistor and a first high-voltage power switch tube which are integrated in the first chips, wherein the first power input end is respectively connected with a drain electrode of the first field effect transistor and a drain electrode of the high-voltage power switch tube; the first current setting end is respectively connected with the grid electrode of the first field effect transistor, the inverting input end of the first operational amplifier and the source electrode of the first high-voltage power switch tube; the source electrode of the first field effect tube and the output end of the first over-temperature adjusting module are connected with the first band gap reference module; the output end of the first operational amplifier is connected with the grid electrode of the first high-voltage power switch tube; the output end of the first bandgap reference module is respectively connected with the positive phase output end of the first operational amplifier; wherein, the liquid crystal display device comprises a liquid crystal display device,
the first field effect transistor is used for reducing the input voltage and outputting the reduced voltage to the first bandgap reference module to generate corresponding reference voltage;
the first over-temperature adjusting module is used for detecting the temperature of the LED driving chip and outputting an over-temperature adjusting signal to the first band gap reference module when the detected temperature reaches a preset temperature threshold value so as to adjust the temperature of the first chip.
Preferably, the LED driving circuit further comprises a first maintenance circuit for controlling the first LED string to stably operate and a second maintenance circuit for controlling the second LED string to stably operate, and the first maintenance circuit is arranged in parallel with the first LED string; the second maintenance circuit is connected with the second LED lamp string in parallel.
Preferably, the first maintenance circuit includes a first dummy load resistor and a first string voltage difference maintaining capacitor, where the first dummy load resistor and the first string voltage difference maintaining capacitor are respectively disposed at two ends of the first LED string in parallel.
Preferably, the second holding circuit includes a second dummy load resistor and a second string voltage difference maintaining capacitor, where the second dummy load resistor and the second string voltage difference maintaining capacitor are respectively disposed at two ends of the second LED string in parallel.
The invention also provides an LED lighting device, which comprises the LED driving circuit; the LED driving circuit comprises a power supply conversion circuit, a first LED lamp string, a second LED lamp string, a first chip module, a first current preset resistor, a second current preset resistor, a line voltage compensation maintaining capacitor, a unidirectional conduction element and a plurality of LED driving chips, wherein the LED driving chips are arranged in parallel; the input end of the power supply conversion circuit is used for accessing alternating voltage, and the output end of the power supply conversion circuit is respectively connected with a plurality of power supply input ends of the first chip module and the input end of the first LED lamp string; the output end of the first LED lamp string is connected with the input end of the unidirectional conduction element; the current setting ends of the first chip module are respectively connected with the output end of the unidirectional conduction element and the first end of the first current preset resistor; the grounding ends of the first chip module are respectively connected with the second end of the first current preset resistor and the input end of the second LED lamp string; the output end of the second LED lamp string is connected with the power input ends of the plurality of LED driving chips and the first ends of the line voltage compensation preset resistors; the second end of the line voltage compensation preset resistor is connected with the line voltage compensation input ends of the LED driving chips and the first ends of the line voltage compensation maintaining capacitors; the second end of the line voltage compensation maintaining capacitor, the grounding ends of the LED driving chips and the first ends of the second current preset resistors are grounded; and the current setting ends of the LED driving chips are connected with the second ends of the second current preset resistors.
According to the LED driving chip, the line voltage compensation module is used for detecting the compensation voltage of the preset resistor through the line voltage compensation input end, after the current to be compensated is generated according to the compensation voltage, the reference voltage input end VREF current which is the positive input end of the operational amplifier is extracted, so that the reference voltage VREF is controlled to linearly decrease, the current flowing through the power switching tube is also decreased, and the power consumption of the power switching tube is kept unchanged. The invention solves the problems of unstable power and serious fluctuation caused by serious heating caused by the increase of power consumption of the power tube when the input voltage of the LED driving chip system is increased.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of an embodiment of an LED driver chip according to the present invention;
FIG. 2 is a schematic circuit diagram of a line voltage compensation module in the LED driving chip of FIG. 1;
fig. 3 is a schematic circuit diagram of an LED driving circuit applied to an LED lighting device according to an embodiment of the present invention.
Reference numerals illustrate:
| reference numerals | Name of the name | Reference numerals | Name of the name |
| 100 | Power supply conversion circuit | C22 | Second lamp string voltage difference maintaining capacitor |
| 200 | First LED lampString | R1 | First current preset resistor |
| 300 | Second LED lamp string | R2 | Second current preset resistor R2 |
| 400 | First chip module | R3 | Line voltage compensation preset resistor |
| 500 | LED driving chip | R4 | Protective resistor |
| 10 | Over-temperature adjusting module | R21 | First dummy load resistor |
| 20 | Band gap reference module | R22 | Second dummy load resistor |
| 30 | Operational amplifier | Q1 | Field effect transistor |
| 40 | Line voltage compensation module | Q2 | High-voltage power switch tube |
| 50 | Low-voltage power supply module | Q41 | First MOS tube |
| 210 | First maintenance circuit | Q42 | Second MOS tube |
| 220 | Second maintenance circuit | Q43 | Third MOS tube |
| C11 | Filter capacitor | Q44 | Fourth MOS tube |
| C1 | Line voltage compensation maintaining capacitor | 110 | Rectifier bridge |
| C21 | First light string voltage difference maintaining capacitor |
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that, if directional indications (such as up, down, left, right, front, and rear … …) are included in the embodiments of the present invention, the directional indications are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.
In addition, if there is a description of "first", "second", etc. in the embodiments 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 a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.
The invention provides an LED driving chip.
Referring to fig. 1 to 3, in an embodiment of the present invention, the LED driving chip 500 includes a power input terminal VIN, a line voltage compensation input terminal LVC, a current setting terminal ISET, and an over-temperature adjustment module 10, a bandgap reference module 20, an operational amplifier 30, a field effect transistor Q1, a high voltage power switch Q2, and a line voltage compensation module 40 integrated in the LED driving chip 500.
Specifically, the power input end VIN is connected to the drain of the field effect transistor Q1 and the drain of the high voltage power switch transistor Q2 respectively; the current setting end ISET is respectively connected with the grid electrode of the field effect transistor Q1, the inverting input end of the operational amplifier 30 and the source electrode of the high-voltage power switch tube Q2; the source electrode of the field effect transistor Q1 and the output end of the over-temperature adjusting module 10 are connected with the band gap reference module 20; the output end of the operational amplifier 30 is connected with the grid electrode of the high-voltage power switch tube Q2; the line voltage compensation input end LVC is connected with the input end of the line voltage compensation module 40; the output end of the line voltage compensation module 40 and the output end of the band gap reference module 20 are respectively connected with the non-inverting output end of the operational amplifier 30; wherein, the liquid crystal display device comprises a liquid crystal display device,
the field effect transistor Q1 is configured to step down an input voltage and output the voltage to the bandgap reference module 20 to generate a corresponding reference voltage;
the over-temperature adjusting module 10 is configured to detect a temperature of the LED driving chip 500, and output an over-temperature adjusting signal to the bandgap reference module 20 when the detected temperature reaches a preset temperature threshold, so as to adjust the temperature of the LED driving chip 500;
the line voltage compensation module 40 is configured to linearly adjust the reference voltage value output to the operational amplifier 30 to compensate the total power of the LED driving chip 500 when detecting that the voltage input by the power input terminal VIN reaches the preset voltage compensation threshold.
In this embodiment, the power input terminal VIN is used for being connected to a DC power supply DC, the fet Q1 preferably uses a high-voltage junction fet Q1, the high-voltage junction fet Q1 obtains a voltage from the power input terminal VIN, and the voltage input by the pinch-off power input terminal VIN of the high-voltage fet Q1 is stepped down to VDD and then output to the bandgap reference voltage module. The bandgap reference module 20 generates a temperature and voltage independent reference voltage to the non-inverting input of the operational amplifier 30 according to the voltage signal output from the fet Q1.
The over-temperature adjustment module 10 detects the temperature of the LED driving chip 500, and outputs an over-temperature adjustment signal to the bandgap reference module 20 when the detected temperature reaches a first preset temperature threshold, so as to control the bandgap reference module 20 to linearly reduce the reference voltage value, thereby reducing the power consumption of the chip and reducing the temperature. If the LED driving chip 500 exceeds a certain second temperature threshold, the reference voltage output to the operational amplifier 30 will drop in an avalanche mode, and the power MOS Q2 in the LED driving chip 500 is in a cut-off state, so as to avoid burning the chip due to the excessively high LED driving chip 500, and at this time, the LED string current is zero, and meanwhile, damage to the LED string can be avoided.
The high-voltage power switch Q2 may be a high-voltage power switch Q2 such as a MOS transistor or an IGBT, and the embodiment is preferably implemented by using a MOS transistor, where the high-voltage power switch Q2 is turned on/off based on the control of the operational amplifier 30, and controls the magnitude of the current flowing through the source/drain of the switch through the peripheral second current preset resistor R2 connected to the current preset terminal, that is, sets the magnitude of the current flowing through the LED string. It will be appreciated that when implemented with IGBTs or other power switching transistors, a corresponding drive circuit may be provided to drive the IGBTs into operation.
It can be understood that, in practical application of the LED driving chip 500, a peripheral line voltage compensation preset resistor R3 is connected in series between the power input terminal VIN and the line voltage compensation input terminal LVC, and a line voltage compensation maintaining capacitor C1 is disposed between the line voltage compensation input terminal LVC and the ground terminal to control the current connected to the line voltage compensation input terminal LVC to change slowly when the line voltage changes linearly. When the voltage input by the power input terminal VIN increases, the line voltage compensation module 40 compensates the voltage of the line voltage compensation input terminal LVC by the compensation voltage of the preset resistor R3, and generates the current to be compensated according to the compensation voltage, and then the line voltage compensation module 40 is turned on as a switch, and extracts the current of the normal phase input terminal of the operational amplifier 30, that is, the reference voltage input terminal VREF, so that the current of the reference voltage input terminal VREF decreases linearly, and thus, the current flowing through the high voltage power switch Q2 decreases. The current reduction value of the high-voltage power switch Q2 can be calculated according to the formula p=ui, that is, under the condition of a certain power, the current reduction value of the high-voltage power switch Q2 is inversely proportional to the voltage increase value of the power input terminal VIN, so as to achieve the purpose of stabilizing the total power.
According to the LED driving chip 500, the line voltage compensation module 40 compensates the compensation voltage of the preset resistor R3 through the line voltage compensation input end LVC, and after the current to be compensated is generated according to the compensation voltage, the current of the normal phase input end of the operational amplifier 30, namely the reference voltage input end VREF, is extracted to control the current of the reference voltage input end VREF to be linearly reduced, so that the current flowing through the high-voltage power switching tube Q2 is reduced, and the power consumption of the high-voltage power switching tube Q2 is kept unchanged. The invention solves the problems that when the input voltage of the system is increased, the power consumption of the power tube is increased and the heat generation is serious, so that the unstable power and the serious fluctuation occur.
In the above embodiment, the LED driving chip 500 further includes a low-voltage power module 50 for supplying power to the operational amplifier 30, an input end of the low-voltage power module 50 is connected to the source of the field effect transistor Q1, and an output end of the low-voltage power module 50 is connected to a power supply end of the operational amplifier 30.
In this embodiment, the low voltage power module 50 generates a constant voltage LVDD from the voltage VDD obtained by the step-down process of the high voltage junction field effect transistor Q1 to provide the power voltage for the operational amplifier 30, so as to drive the operational amplifier 30 to operate.
Referring to fig. 1 to 3, in a preferred embodiment, the LED driving chip 500 further includes a ground terminal, the line voltage compensation module 40 includes a first MOS transistor Q41, a second MOS transistor Q42, a third MOS transistor Q43, and a fourth MOS transistor Q44, the drain electrode of the first MOS transistor Q41 is an input terminal of the line voltage compensation module 40 and is interconnected with the gate electrode, the line voltage compensation input terminal LVC, and the gate electrode of the third MOS transistor Q43, and the source electrode of the first MOS transistor Q41 is interconnected with the gate electrode and the drain electrode of the second MOS transistor Q42, and the gate electrode of the fourth MOS transistor Q44; the drain electrode of the third MOS transistor Q43 is the output end of the line voltage compensation module 40, and the source electrode of the third MOS transistor Q43 is connected with the drain electrode of the fourth MOS transistor Q44; the drain electrode of the second MOS transistor Q42 is connected to the drain electrode of the fourth MOS transistor Q44 and the ground GND.
In this embodiment, the first MOS transistor Q41 receives the compensation voltage through the line voltage compensation input end LVC, that is, the voltage drop on the line voltage compensation preset resistor R3, and the line voltage compensation preset resistor R3 is further used to limit the current output to the line voltage compensation module 40, so as to avoid burning the MOS transistor due to excessive current. The first MOS transistor Q41 and the second MOS transistor Q42 adopt a diode connection method, current to be compensated is generated with a peripheral line voltage compensation preset resistor R3, the proportional relationship between the current value flowing through the third MOS transistor Q43 and the fourth MOS transistor Q44 and the current value flowing through the first MOS transistor Q41 and the second MOS transistor Q42 is 1:N (wherein N is greater than 0), the current on the peripheral line voltage compensation preset resistor R3 is mirrored by a current path formed by the first MOS transistor Q41 and the second MOS transistor Q42, namely when the voltage of a power input end VIN is increased, the current is mirrored to the current path formed by the Q43 and the Q44, and the mirrored proportion is N;1, when the third MOS transistor Q43 and the fourth MOS transistor Q44 are turned on, the current value output by the bandgap reference module 20 extracted from the non-inverting input end of the operational amplifier 30 is 1/N of the current value flowing through R3, so that the power of the high-voltage power switch transistor Q2 remains unchanged basically during the working process. By the arrangement, the voltage of the non-inverting input end of the operational amplifier 30 is linearly reduced, the current flowing through the power tube is also reduced, the heat of the power tube is small, and the stable total power is basically kept unchanged.
The invention further provides an LED driving circuit.
Referring to fig. 1 to 3, in an embodiment of the invention, the LED driving circuit includes a power conversion circuit 100, a first LED string 200, a second LED string 300, a first chip module 400, a first current preset resistor R1, a second current preset resistor R2, a line voltage compensation preset resistor R3, a line voltage compensation maintaining capacitor C1, a unidirectional conductive element D1, and a plurality of LED driving chips 500 as described above.
A plurality of the LED driving chips 500 are arranged in parallel; the input end of the power conversion circuit 100 is used for accessing an ac voltage Vac, and the output end of the power conversion circuit 100 is respectively connected with a plurality of power input ends VIN of the first chip module 400 and the input end of the first LED light string 200; the output end of the first LED light string 200 is connected with the input end of the unidirectional conducting element D1; the plurality of current setting terminals ISET of the first chip module 400 are respectively interconnected with the output terminal of the unidirectional conduction element D1 and the first terminal of the first current preset resistor R1; the plurality of grounding terminals of the first chip module 400 are respectively interconnected with the second terminal of the first current preset resistor R1 and the input terminal of the second LED string 300; the output end of the second LED string 300 is interconnected with the power input ends VIN of the LED driving chips 500 and the first ends of the line voltage compensation preset resistor R3; the second end of the line voltage compensation preset resistor R3 is interconnected with the line voltage compensation input ends LVC of the LED driving chips 500 and the first ends of the line voltage compensation maintaining capacitors C1; the second end of the line voltage compensation maintaining capacitor C1, the grounding ends of the LED driving chips 500, and the first ends of the second current preset resistor R2 are grounded; the current setting terminals ISET of the plurality of LED driving chips 500 (U21 to U2N) are connected to the second terminal of the second current preset resistor R2.
In this embodiment, the detailed structure of the LED driving chip 500 can refer to the above embodiment, and will not be described herein. The unidirectional conduction element D1 is an isolation diode, and the unidirectional conduction element D1 is used for preventing the current output by the first chip module 400 from flowing backward to the first LED light string 200, thereby affecting the normal operation of the first LED light string 200. In order to avoid breakdown of the isolation diode caused by excessive current flowing through the isolation diode, the protection resistor R4 is further disposed in parallel at two ends of the isolation diode in the embodiment.
The power conversion circuit 100 includes a rectifier bridge 110 and a filter capacitor C11, where the rectifier bridge 110 rectifies an input ac power and outputs a dc power to a dc bus DCBUS, and the filter capacitor C11 filters the dc power to provide a working voltage for the lamp string with the first chip module 400 and other circuit modules.
In the above embodiment, the first chip module includes a plurality of first chips (not shown), where the first chips include a first power input end, a first line voltage compensation input end, a first current setting end, and a first over-temperature adjustment module, a first bandgap reference module, a first operational amplifier, a first field effect transistor, and a first high-voltage power switch tube integrated in the first chips, and the first power input end is connected to a drain electrode of the first field effect transistor and a drain electrode of the high-voltage power switch tube, respectively; the first current setting end is respectively connected with the grid electrode of the first field effect transistor, the inverting input end of the first operational amplifier and the source electrode of the first high-voltage power switch tube; the source electrode of the first field effect tube and the output end of the first over-temperature adjusting module are connected with the first band gap reference module; the output end of the first operational amplifier is connected with the grid electrode of the first high-voltage power switch tube; the output end of the first bandgap reference module is respectively connected with the positive phase output end of the first operational amplifier; wherein, the liquid crystal display device comprises a liquid crystal display device,
the first field effect transistor is used for reducing the input voltage and outputting the reduced voltage to the first bandgap reference module to generate corresponding reference voltage;
the first over-temperature adjusting module is used for detecting the temperature of the LED driving chip and outputting an over-temperature adjusting signal to the first band gap reference module when the detected temperature reaches a preset temperature threshold value so as to adjust the temperature of the first chip.
It can be understood that the first chip may further integrate the line voltage compensation module 40, and the function and structure of the first chip integrated with the line voltage compensation module 40 are the same as those of the LED driving chip 500, and the detailed description thereof will be omitted herein. Referring to fig. 3, a plurality of first chips (U11 to U1N) are arranged in parallel and turned on/off according to a voltage input from a dc bus DCBUS to drive a first string light to operate. Of course, the first chip may also be implemented by using the LED driving chip 500, and in practical application, the line voltage compensation input end LVC of the LED driving chip 500 may be grounded or suspended. Or when the chip is packaged, the voltage compensation input end is not led out.
Specifically, when the voltage input by the dc bus DCBUS is less than the first voltage threshold, the voltage cannot drive the first LED string 200 and the second LED string 300 to operate, and at this time, both the first LED string 200 and the second LED string 300 are in the off state and are not turned on.
When the voltage input by the dc bus DCBUS is greater than the first voltage threshold and less than the second voltage threshold, the power input end VIN of the first chip module 400 is connected to the voltage input by the dc bus DCBUS, so that the first high-voltage power switch Q2 is turned on and starts to work, and the voltage input by the dc bus DCBUS is saturated and dropped through the second LED string 300 via the ground end of the first chip module 400, and then the second LED string 300 is turned on. At this time, the total current flowing through the first chip module 400 is set by the first current preset resistor R1, so that the total current flowing through the first chip module 400, that is, the current flowing through the second LED string 300, can be adjusted by adjusting the resistance value of the first current preset resistor R1. Then, the current is output to the LED driving chip 500 to make the LED driving chip 500 work normally, and the current flowing through the LED driving chip 500 will passively follow the current value of the first chip module 400, i.e. the current of the second LED string 300 can be set according to the first current preset resistor R1.
When the voltage input by the dc bus DCBUS is greater than the second voltage threshold, the first power tube in the first chip module 400 is turned off, and at this time, the first LED string 200 and the second LED string 300 are in a series connection relationship, and the voltage input by the dc bus DCBUS is applied to the LED driving chips after passing through the saturation voltage drops of the first LED string 200, the isolation diode and the second LED string 300, and at this time, the total current flowing through each LED driving chip 500 is set by the second current preset resistor R2, so that the total current flowing through the first chip module 400, that is, the current flowing through the first LED string 200 and the second LED string 300, can be adjusted by adjusting the resistance of the second current preset resistor R2. At this time, the line voltage compensation preset resistor R3 and the line voltage compensation maintaining capacitor C1 implement line voltage compensation for the LED driving chip 500.
It should be noted that, the common single-stage linear constant current dimming mode has the defects of short dimming stroke and long dead time, so that flickering occurs when the LED string is dimmed deeply. When the deep dimming is performed, the voltage input by the DC bus DCBUS is larger than the first voltage threshold and smaller than the second voltage threshold, the LED lamp can be dimmed according to the working condition, the lower the saturation voltage drop of the LED lamp is, the lower the strobe index is, the problem of strobe in the deep dimming can be solved, and the problems of single-section linear constant current dimming stroke and short dead time are solved.
Referring to fig. 1 to 3, in a preferred embodiment, the LED driving circuit further includes a first maintenance circuit 210 for controlling the first LED string 200 to stably operate and a second maintenance circuit 220 for controlling the second LED string 300 to stably operate, wherein the first maintenance circuit 210 is disposed in parallel with the first LED string 200; the second maintenance circuit 220 is disposed in parallel with the second LED string 300.
The first maintenance circuit 210 includes a first dummy load resistor R21 and a first string voltage difference maintaining capacitor C21, where the first dummy load resistor R21 and the first string voltage difference maintaining capacitor C21 are respectively disposed at two ends of the first LED string 200 in parallel.
The second holding circuit 220 includes a second string voltage difference maintaining capacitor C22 and a second string voltage difference maintaining capacitor, where the second string voltage difference maintaining capacitor C22 and the second string voltage difference maintaining capacitor are respectively disposed at two ends of the second LED string 300 in parallel.
In this embodiment, the first dummy load resistor R21, the first string voltage difference maintaining capacitor C21, the second string voltage difference maintaining capacitor C22, and the second dummy load resistor R22 are all used for controlling and maintaining the stable and reliable operation of the first LED string 200 and the second LED string 300.
The invention also provides an LED lighting device which comprises the LED driving circuit. It can be understood that, since the LED driving circuit is used in the LED lighting device of the present invention, the embodiments of the LED lighting device of the present invention include all the technical schemes of all the embodiments of the LED driving circuit, and the achieved technical effects are identical, and are not described herein again.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the invention, and all equivalent structural changes made by the description of the present invention and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the invention.
Claims (8)
1. The LED driving chip is characterized by comprising a power input end, a line voltage compensation input end, a current setting end, an over-temperature adjusting module, a band gap reference module, an operational amplifier, a field effect tube, a high-voltage power switching tube and a line voltage compensation module which are integrated in the LED driving chip, wherein the power input end is respectively connected with a drain electrode of the field effect tube and a drain electrode of the high-voltage power switching tube; the current setting end is respectively connected with the grid electrode of the field effect transistor, the inverting input end of the operational amplifier and the source electrode of the high-voltage power switch tube; the source electrode of the field effect tube and the output end of the over-temperature regulating module are connected with the band gap reference module; the output end of the operational amplifier is connected with the grid electrode of the high-voltage power switch tube; the line voltage compensation input end is connected with the input end of the line voltage compensation module; the output end of the line voltage compensation module and the output end of the band gap reference module are respectively connected with the non-inverting input end of the operational amplifier; wherein, the liquid crystal display device comprises a liquid crystal display device,
the field effect transistor is a high-voltage junction field effect transistor and is used for reducing the input voltage and outputting the reduced voltage to the band gap reference module to generate corresponding reference voltage;
the over-temperature adjusting module is used for detecting the temperature of the LED driving chip and outputting an over-temperature adjusting signal to the band gap reference module when the detected temperature reaches a preset temperature threshold value so as to adjust the temperature of the LED driving chip;
the line voltage compensation module is used for linearly adjusting the reference voltage value output to the operational amplifier when the voltage input by the power input end is detected to reach the preset voltage compensation threshold value so as to compensate the total power of the LED driving chip; the LED driving chip further comprises a grounding end, the line voltage compensation module comprises a first MOS tube, a second MOS tube, a third MOS tube and a fourth MOS tube, the drain electrode of the first MOS tube is the input end of the line voltage compensation module and is connected with the grid electrode of the first MOS tube, the line voltage compensation input end and the grid electrode of the third MOS tube, and the source electrode of the first MOS tube is connected with the grid electrode of the second MOS tube, the drain electrode of the second MOS tube and the grid electrode of the fourth MOS tube; the drain electrode of the third MOS tube is the output end of the line voltage compensation module, and the source electrode of the third MOS tube is connected with the drain electrode of the fourth MOS tube; the source electrode of the second MOS tube is connected with the source electrode of the fourth MOS tube and the grounding end.
2. The LED driver chip of claim 1, further comprising a low voltage power supply module that powers the operational amplifier, an input of the low voltage power supply module being connected to a source of the field effect transistor, an output of the low voltage power supply module being connected to a power supply of the operational amplifier.
3. The LED driver chip of claim 1 or 2, wherein the high voltage power switching transistor is a MOS transistor.
4. An LED driving circuit, comprising a power conversion circuit, a first LED string, a second LED string, a first chip module, a first current preset resistor, a second current preset resistor, a line voltage compensation maintenance capacitor, a unidirectional conduction element, and a plurality of LED driving chips according to any one of claims 1 to 3, wherein a plurality of LED driving chips are arranged in parallel; the input end of the power supply conversion circuit is used for accessing alternating voltage, and the output end of the power supply conversion circuit is respectively connected with a plurality of power supply input ends of the first chip module and the input end of the first LED lamp string; the output end of the first LED lamp string is connected with the input end of the unidirectional conduction element; the current setting ends of the first chip module are respectively connected with the output end of the unidirectional conduction element and the first end of the first current preset resistor; the grounding ends of the first chip module are respectively connected with the second end of the first current preset resistor and the input end of the second LED lamp string; the output end of the second LED lamp string is connected with the power input ends of the plurality of LED driving chips and the first ends of the line voltage compensation preset resistors; the second end of the line voltage compensation preset resistor is connected with the line voltage compensation input ends of the LED driving chips and the first ends of the line voltage compensation maintaining capacitors; the second end of the line voltage compensation maintaining capacitor, the grounding ends of the LED driving chips and the first ends of the second current preset resistors are grounded; the current setting ends of the LED driving chips are connected with the second ends of the second current preset resistors;
the first chip module comprises a plurality of first chips, wherein each first chip comprises a first power input end, a first line voltage compensation input end, a first current setting end, and a first over-temperature adjusting module, a first bandgap reference module, a first operational amplifier, a first field effect transistor and a first high-voltage power switch tube which are integrated in the first chip, and the first power input end is respectively connected with the drain electrode of the first field effect transistor and the drain electrode of the high-voltage power switch tube; the first current setting end is respectively connected with the grid electrode of the first field effect transistor, the inverting input end of the first operational amplifier and the source electrode of the first high-voltage power switch tube; the source electrode of the first field effect tube and the output end of the first over-temperature adjusting module are connected with the first band gap reference module; the output end of the first operational amplifier is connected with the grid electrode of the first high-voltage power switch tube; the output end of the first bandgap reference module is respectively connected with the non-inverting input end of the first operational amplifier; wherein, the liquid crystal display device comprises a liquid crystal display device,
the first field effect transistor is used for reducing the input voltage and outputting the reduced voltage to the first bandgap reference module to generate corresponding reference voltage;
the first over-temperature adjusting module is used for detecting the temperature of the LED driving chip and outputting an over-temperature adjusting signal to the first band gap reference module when the detected temperature reaches a preset temperature threshold value so as to adjust the temperature of the first chip.
5. The LED driving circuit of claim 4, further comprising a first maintenance circuit for controlling the first LED string to operate steadily and a second maintenance circuit for controlling the second LED string to operate steadily, the first maintenance circuit being arranged in parallel with the first LED string; the second maintenance circuit is connected with the second LED lamp string in parallel.
6. The LED driving circuit of claim 5, wherein the first holding circuit comprises a first dummy load resistor and a first string voltage difference maintaining capacitor, the first dummy load resistor and the first string voltage difference maintaining capacitor being respectively arranged in parallel at two ends of the first LED string.
7. The LED driving circuit of claim 5, wherein the second holding circuit comprises a second dummy load resistor and a second string voltage difference maintaining capacitor, the second dummy load resistor and the second string voltage difference maintaining capacitor being respectively arranged at two ends of the second LED string in parallel.
8. An LED lighting device comprising the LED driving circuit according to any one of claims 4 to 7.
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| CN109496040A (en) * | 2018-11-20 | 2019-03-19 | 广州市力驰微电子科技有限公司 | Great power LED linear constant current drive control chip |
| CN109756204B (en) * | 2019-03-05 | 2023-11-14 | 广东合微集成电路技术有限公司 | Filter, oscillation generating circuit and electronic device |
| CN111239465B (en) * | 2020-01-16 | 2023-05-23 | 昂宝电子（上海）有限公司 | Line voltage detection circuit, system and method |
| CN112235909B (en) * | 2020-11-03 | 2023-06-02 | 厦门亚成微电子有限责任公司 | Charging and discharging method and circuit of LED driving chip |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013078669A1 (en) * | 2011-12-02 | 2013-06-06 | Ye Jun | Led drive circuit and led drive chip |
| CN105548672A (en) * | 2016-01-27 | 2016-05-04 | 深圳市瑞之辰科技有限公司 | Over-current detection circuit of power switch |
| CN105554954A (en) * | 2016-01-26 | 2016-05-04 | 佛山市南海区联合广东新光源产业创新中心 | Control chip for LED (Light-Emitting Diode) driving |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012053825A2 (en) * | 2010-10-20 | 2012-04-26 | Seoul Semiconductor Co., Ltd. | Light emitting diode driving device |
| CN117412436A (en) * | 2013-08-09 | 2024-01-16 | 意法半导体研发(深圳)有限公司 | Driving device for light emitting apparatus and method thereof |
| CN207427526U (en) * | 2017-11-09 | 2018-05-29 | 深圳市瑞之辰科技有限公司 | LED drive chip, LED drive circuit and LED light device |
-
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013078669A1 (en) * | 2011-12-02 | 2013-06-06 | Ye Jun | Led drive circuit and led drive chip |
| CN105554954A (en) * | 2016-01-26 | 2016-05-04 | 佛山市南海区联合广东新光源产业创新中心 | Control chip for LED (Light-Emitting Diode) driving |
| CN105548672A (en) * | 2016-01-27 | 2016-05-04 | 深圳市瑞之辰科技有限公司 | Over-current detection circuit of power switch |
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