CN109246889B - DC-DC and linear combination LED driving circuit, driving method thereof and storage medium - Google Patents
DC-DC and linear combination LED driving circuit, driving method thereof and storage medium Download PDFInfo
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- CN109246889B CN109246889B CN201811124503.4A CN201811124503A CN109246889B CN 109246889 B CN109246889 B CN 109246889B CN 201811124503 A CN201811124503 A CN 201811124503A CN 109246889 B CN109246889 B CN 109246889B
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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]
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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
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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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
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Abstract
The invention provides a DC-DC and linear combined LED driving circuit, a driving method thereof and a storage medium. The invention can improve the LED driving efficiency, reduce the system cost and simply and reliably meet the open-circuit protection requirement of the LED.
Description
Technical Field
The invention relates to the technical field of LED driving, in particular to a DC-DC and linear combination LED driving circuit, a driving method thereof and a storage medium.
Background
Along with the popularization of the application of the LEDs in the field of automobile lamps, the driving modes of the LEDs are also various in form, and various classifications are formed. There are three main categories: 1) Resistance type: the efficiency is the lowest, the driving calorific value is large, and the cost is the lowest; 2) Linear constant current type: the efficiency is lower, the driving heating value is large, and the cost is moderate; 3) The DC-DC constant current type has the highest efficiency, small driving heating value and higher cost. The three modes have advantages and disadvantages.
The current mainstream LED driving method mostly adopts a resistance type or linear constant current type, generally adopts 1-3 LED strings, and builds a complex LED open-circuit protection circuit by using discrete devices, but the resistance type or linear constant current type circuit has high error rate, and the requirement that the input current is always larger than the minimum working current (for example 65 mA) regulated by the regulation in normal operation or is always smaller than the maximum fault current (for example 10 mA) regulated by the regulation after the open-circuit protection is started is hardly met under the input voltage range (for example 9V-16V) and the high and low temperature environment temperature (for example-40-85 ℃). In addition, the system has low efficiency and large driving heating value, so that the car lamp has difficult thermal and structural design, and the car lamp volume is forced to be increased.
The LED is usually in a full series structure by adopting a DC-DC constant current driving mode, but is limited by the voltage resistance of a DC-DC chip, the number of the LEDs connected in series is limited, the requirements of light distribution and modeling are difficult to meet, and the application range is limited due to the cost pressure.
Therefore, the current driving method of the LED for the mainstream vehicle generally has the troublesome problems of low driving efficiency, large heating value, difficult satisfaction of regulations during open circuit protection of the LED, high cost and the like. When the requirements of small size, high cost pressure, more LEDs and open-circuit protection of LEDs are met, the current main current practice is always in the hope of being out of the way. Therefore, there is a need for an LED open-circuit protection circuit that has high driving efficiency, small driving heat generation, low cost, and is simple and reliable.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, the present invention is to provide a DC-DC and linear combined LED driving circuit, a driving method thereof, and a storage medium thereof, for solving the troublesome problems of low driving efficiency, large heat generation, difficulty in meeting regulations during open circuit protection of LEDs, high cost, and the like in the existing LED driving method.
To achieve the above and other related objects, the present invention provides a DC-DC and linear combination LED driving circuit, comprising: the LED lamp comprises a DC-DC constant voltage driving module, a linear control chip, one or more lines containing an LED lamp group and a protection circuit; the DC-DC constant voltage driving module includes: an input end and an output end; the input end is connected with an external power supply; the linear control chip includes: the voltage input end, the detection end and the control end; the voltage input end is connected with the output end of the DC-DC constant voltage driving module; one end of each circuit is connected with the output end of the DC-DC constant voltage driving module, and the other end of each circuit is grounded; the protection circuit includes: a detection branch and a control branch corresponding to each line; each detection branch is connected between the detection end and a detection point in the corresponding circuit so as to detect the on or off of the circuit; each of the control branches comprises: the switch unit is arranged in the circuit, and the switch state of the switch unit is used for controlling the on or off of the circuit; the switch unit is provided with a signal end connected to the control end and is used for controlling the switch state of the switch component according to an input signal.
In an embodiment of the present invention, the detection branch includes: a first diode and a first resistor; the positive electrode of the first diode is connected with the detection end of the linear control chip; the negative electrode of the first diode is respectively connected with one end of the LED lamp group in the corresponding circuit, one end of the first resistor and one end of the switch unit in the control branch; the other end of the first resistor is grounded.
In an embodiment of the present invention, the switching unit includes: a switching element, a second resistor, and a third resistor; the first end of the switching element is respectively connected with one end of the LED lamp group in the circuit, the cathode of the first diode and one end of the first resistor; the second end of the switching element is connected with one end of the second resistor; the other end of the second resistor is connected with the control end of the linear control chip; the third end of the switching element is connected with one end of the third resistor; the other end of the third resistor is grounded; the second end of the switching element is used for controlling the on-off of the first end and the third end of the switching element.
In an embodiment of the invention, the switching element is an NPN transistor, or a MOS transistor, or an analog switch.
In an embodiment of the invention, the device further comprises a filter circuit connected with the DC-DC constant voltage driving module; the filter circuit includes: the second diode, the inductor, the first capacitor and the second capacitor; the anode of the second diode is connected with external voltage; the negative electrode of the second diode is connected with one end of the inductor and one end of the first capacitor respectively; the other end of the inductor is connected with the input end of the DC-DC constant voltage driving module and one end of the second capacitor respectively; the other end of the first capacitor, the other end of the second capacitor and the grounding end of the DC-DC constant voltage driving module are grounded respectively.
In an embodiment of the invention, the device further includes a fourth resistor connected to the linear control chip; one end of the fourth resistor is connected with the enabling end of the linear control chip; the other end of the fourth resistor is grounded; and setting different resistance values of the fourth resistor to enable the detection end and the control end of the linear control chip to be effective or invalid.
In an embodiment of the invention, the device further includes a fifth resistor and a sixth resistor connected to the linear control chip; one end of the fifth resistor is connected with the reference voltage output end of the linear control chip; the other end of the fifth resistor is respectively connected with one end of the sixth resistor and the adjusting end of the linear control chip; the other end of the sixth resistor is grounded; the adjusting end is used for adjusting the reference voltage output by the reference voltage output end.
In an embodiment of the invention, the linear control chip further includes a voltage adjustment output end, so as to output the reference voltage adjusted by the adjustment end; the voltage regulation output end is respectively connected with a third end of the switching element and one end of the third resistor in any circuit so as to enable the input current of each circuit and the control branch connected with the circuit to be more stable.
In an embodiment of the invention, any one or more of the LED lamp sets are replaced with resistors as compensation circuits for ensuring that the input current is constantly greater than the minimum operating current specified by the regulations during normal operation.
In an embodiment of the invention, the LED lamp set is one or more LED light sources connected in series.
To achieve the above and other related objects, the present invention provides an LED driving method applied to an LED driving circuit of DC-DC and linear combination as described above, the method comprising: detecting an open circuit signal; and when the open-circuit signal is detected, sending an open-circuit instruction to a signal end so as to open the switch unit.
To achieve the above and other related objects, the present invention provides a computer-readable storage medium having stored thereon an LED driving program which, when executed by a processor, implements the above-described LED driving method.
As described above, the present invention provides a DC-DC and linear combined LED driving circuit, a driving method thereof, and a storage medium. The following beneficial effects are achieved:
the LED driving efficiency is improved, the system cost is reduced, the regulation requirement is met, and the LED open-circuit protection requirement is met simply and reliably.
Drawings
FIG. 1 is a schematic diagram of a DC-DC combined with linear LED driving circuit according to an embodiment of the present invention;
FIG. 2 is a schematic circuit diagram of a DC-DC combined with linear LED driving circuit according to an embodiment of the present invention;
FIG. 3 is a flow chart of an LED driving method according to an embodiment of the invention;
description of element reference numerals
110 DC-DC constant voltage driving module
120. Linear control chip
130. Circuit arrangement
131 LED lamp set
140. Protection circuit
141. Detection branch
142. Control branch
143. Switch unit
S301-S302 method steps
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict.
It should be noted that the illustrations provided in the following embodiments merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complicated.
As shown in fig. 1, a schematic block diagram of a DC-DC and linear combined LED driving circuit according to an embodiment of the present invention is shown, where the DC-DC and linear combined LED driving circuit includes: the LED lamp set comprises a DC-DC constant voltage driving module 110, a linear control chip 120, one or more lines 130 containing an LED lamp set 131 and a protection circuit 140.
In an embodiment of the present invention, the DC-DC constant voltage driving module 110 includes: an input end and an output end; the input end is connected with an external power supply.
In an embodiment of the present invention, the external power source may be a battery, and the external power source preferably has a voltage of 9-16V.
In one embodiment of the present invention, the DC-DC constant voltage driving module may be reduced from 9V-16V to a smaller constant voltage, thereby improving system efficiency.
In an embodiment of the present invention, the DC-DC constant voltage driving mode of the DC-DC constant voltage driving module 110 is different from the conventional DC-DC constant current driving mode in that: in the DC-DC constant current driving mode, LEDs need to be in a full series structure, and are limited by the withstand voltage of a DC-DC chip, so that the number of the LEDs connected in series is limited, and the requirements of light distribution and structural design are hardly met; the DC-DC constant voltage driving mode can lead the multi-path LED lamp group to be in a parallel structure, the total number of LEDs is not limited, the requirements of light distribution and structural design can be met, and meanwhile, an additional DC-DC chip is not required to be added, so that the cost is reduced.
In an embodiment of the present invention, the linear control chip 120 includes: a voltage input end A, a detection end B and a control end C; and the voltage input end A is connected with the output end of the DC-DC constant voltage driving module.
In an embodiment of the invention, the linear control chip 120 is an eight-terminal adjustable linear LED driving control chip.
In an embodiment of the present invention, one end of each of the lines 130 is connected to the output end of the DC-DC constant voltage driving module, and the other end is grounded.
In an embodiment of the present invention, each of the circuits 130 includes an LED lamp set 131, specifically, one end of the LED lamp set 131 is connected to the output end of the DC-DC constant voltage driving module 110, and the other end is grounded.
In an embodiment of the present invention, any one or more of the LED lamp sets 131 are replaced with resistors, so as to be used as a compensation circuit for ensuring that the input current is always greater than the minimum operating current specified by the regulations during normal operation.
For example, LED driving circuits typically require that the input current be constantly greater than the minimum operating current specified by regulations (e.g., 65 mA) during normal operation over an input voltage range (e.g., 9V-16V) and at high and low ambient temperatures (e.g., -40-85 ℃).
In an embodiment of the present invention, since the driving circuit of the present invention connects the LED lamp sets 131 in parallel, the input current may generate a minimum operating current which cannot meet the regulation of the regulations, and in an embodiment of the present invention, the LED lamp sets 131 are replaced by resistors as compensation circuits to increase the total input current of the driving circuit of the present invention.
Because the LED driving circuit of the present invention connects the LED lamp groups 131 in parallel, each LED lamp group 131 may not meet the minimum working current which is constantly greater than the regulation in normal operation, so any one or more LED lamp groups 131 are appropriately selected to be replaced with resistors to compensate the output current of other LED lamp groups, thereby ensuring that each LED lamp group in the LED driving circuit of the present invention can meet the minimum working current which is constantly greater than the regulation in normal operation.
In an embodiment of the invention, the LED lamp set 131 is one or more LED light sources connected in series.
In an embodiment of the present invention, because the voltage-withstanding capability of the DC-DC constant voltage driving module 110 is limited, the number of LED light sources in the LED lamp set 131 of each circuit 130 is limited to 1-4, and in order to ensure the stability of the overall driving circuit, it is preferable that two LED light sources are connected in series to the LED lamp set 131. However, the number of the LED light sources connected in series with the LED lamp set is not limited to two or more in the embodiment of the present invention.
In an embodiment of the present invention, the protection circuit 140 includes: a detection branch 141 and a control branch 142 corresponding to each of the lines.
In an embodiment of the present invention, the protection circuit 140 is mainly connected to the detection end B and the control end C of each of the circuits 130 and the linear control chip 120. The detecting branch 141 is configured to detect whether an open circuit condition occurs in each of the lines 130, and the control branch 142 is configured to disconnect when an open circuit condition occurs in the line 130 is detected, so as to protect the line 130.
In an embodiment of the present invention, each of the detecting branches 142 is connected between the detecting terminal B and a detecting point in the corresponding line 130 to detect the on or off of the line 130.
In an embodiment of the present invention, the detecting branch 141 may be configured with a detecting element, such as a diode, for detecting. For example, when the LED lamp sets 131 of one of the lines 130 are open, the detection branch 141 forms a loop, the positive electrode of the diode presents a low level, and the detection end B of the linear control chip 120 receives the low level, so as to determine that the LED lamp sets 131 of one of the lines 130 are open.
In one embodiment of the present invention, each of the control branches 142 includes: a switch unit 143 disposed in the line 130, wherein a switch state of the switch unit is used for controlling on or off of the line 130; the switching unit 143 has a signal terminal b connected to the control terminal C for controlling the switching state of the switching part according to an input signal.
In an embodiment of the present invention, the control branches 142 are connected when the LED lamp sets 131 are normal, and when the detection end B of the linear control chip 120 receives a low level, the control end C of the linear control chip 120 sends an off command to the signal end B of the switch unit to control the switch unit 143 to be turned off, so that each control branch 142 is disconnected from the LED lamp set 131, i.e. each line 130 is disconnected, thereby protecting each line 130 and the LED lamp set 131 included therein.
As shown in fig. 2, a schematic circuit diagram of a DC-DC and linear combination LED driving circuit in an embodiment of the present invention is shown. The lines connecting multiple sets of LED lamps are shown to further detail embodiments of the invention by being shown in a circuit schematic.
In an embodiment of the invention, the DC-DC and linear combination LED driving circuit includes: the LED lamp comprises a DC-DC constant voltage driving module, a linear control chip, one or more lines containing an LED lamp group and a protection circuit; the DC-DC constant voltage driving module includes: an input end and an output end; the input end is connected with an external power supply.
In an embodiment of the invention, the DC-DC constant voltage driving module in fig. 2 corresponds to the DC-DC constant voltage driving module 110 in fig. 1, the linear control chip U1 in fig. 2 corresponds to the linear control chip 120 in fig. 1, the one or more lines including the LED lamp set in fig. 2 corresponds to the one or more lines 130 including the LED lamp set in fig. 1, wherein the LED1 and the LED2 in fig. 2 form a LED lamp set 131 in fig. 1, and the protection circuit in fig. 2 corresponds to the protection circuit 140 in fig. 1.
In an embodiment of the present invention, the linear control chip U1 includes: a voltage input terminal VCC, a detection terminal VF, and a control terminal OUT; the voltage input end VCC is connected with the output end of the DC-DC constant voltage driving module.
In an embodiment of the invention, the voltage input terminal VCC in fig. 2 corresponds to the voltage input terminal a of the linear control chip 120 in fig. 1, the detection terminal VF in fig. 2 corresponds to the detection terminal B of the linear control chip 120 in fig. 1, and the control terminal OUT in fig. 2 corresponds to the control terminal C of the linear control chip 120 in fig. 1. The voltage input end VCC of the linear control chip U1 is connected with the output end of the DC-DC constant voltage driving module.
In an embodiment of the present invention, the linear control chip U1 is preferably an AL5814 chip or an NCV7692 chip.
For example, the AL5814 chip is an 8-terminal adjustable linear LED driving controller, which is suitable for a wide input voltage range of 4.5V to 60V, and has minimal internal power consumption compared with a conventional linear LED driver by using an external LED driving power supply device. This makes it an ideal choice for medium to high current LED circuits. AL5814 has internal output driving capability up to 15mA, can be used for driving an external bipolar transistor or MOSFET, and can also drive a plurality of LED channels to provide a dimmable and adjustable driving current for an LED lamp, and the efficiency reaches more than 80%.
In an embodiment of the present invention, the detection branch includes: a first diode D1 and a first resistor R1; the positive electrode of the first diode D1 is connected with the detection end VF of the linear control chip U1; the negative electrode of the first diode D1 is respectively connected with one end of the LED lamp group in the corresponding circuit, one end of the first resistor R1 and one end of the switch unit in the control branch; the other end of the first resistor R1 is grounded.
In an embodiment of the invention, the detection element in the detection branch is a diode. For example, when the LED lamp set is normally connected, the LED lamp set receives the voltage output by the DC-DC constant voltage driving module, and then flows through the LED lamp set to be output to one end of the control branch switch unit. At this time, the negative electrode of the first diode D1 is at a high level. When the LED lamp set is opened, the first diode D1, the first resistor R1, and the detection terminal VF form a loop, and the positive electrode of the first diode D1 is at a low level and is transmitted to the detection terminal VF, so as to detect that the LED lamp set is opened.
In an embodiment of the present invention, the switching unit includes: a switching element TR1, a second resistor R2, and a third resistor R3; the first end of the switching element TR1 is connected to one end of the LED lamp set in the circuit, the cathode of the first diode D1, and one end of the first resistor R1, which correspond to the first end of the switching element TR 1; a second end of the switching element TR1 is connected with one end of the second resistor R2; the other end of the second resistor R2 is connected with a control end OUT of the linear control chip U1; a third terminal of the switching element TR1 is connected to one terminal of the third resistor R3; the other end of the third resistor R3 is grounded; the second terminal of the switching element TR1 is used to control the on-off of the first terminal and the third terminal thereof.
In an embodiment of the present invention, when the detection end VF of the linear control chip U1 detects an open signal, the control end OUT of the linear control chip U1 outputs an open command to the second end of the switching element TR1 of each circuit, and after receiving the open command, the first end and the third end of the switching element TR1 are disconnected to disconnect the LED lamp groups, so that all the LED lamp groups are turned off, and all the LED lamp groups are protected. For example, the control terminal OUT is set to a low level to turn off the switching element TR1.
In an embodiment of the invention, the switching element TR1 is an NPN transistor, or a MOS transistor, or an analog switch.
In an embodiment of the invention, the switching element TR1 is a common three-terminal switching element.
For example, if the switching element TR1 is an NPN triode, the collectors of the NPN triode are respectively connected to one end of the LED lamp set in the corresponding line; the base electrode of the NPN triode is connected with one end of the second resistor R2; and an emitter of the NPN triode is connected with one end of the third resistor R3.
In an embodiment of the present invention, the device further includes a fourth resistor R4 connected to the linear control chip U1; one end of the fourth resistor R4 is connected with the enabling end SF of the linear control chip U1; the other end of the fourth resistor R4 is grounded; the detection end VF and the control end OUT of the linear control chip U1 are enabled or disabled by setting different resistance values of the fourth resistor R4.
In an embodiment of the present invention, the fourth resistor R4 is configured to cooperate with the enable terminal SF, so as to turn on or off the protection circuit, thereby enhancing flexibility and adaptability.
In an embodiment of the present invention, the device further includes a fifth resistor R5 and a sixth resistor R6 connected to the linear control chip U1; one end of the fifth resistor R5 is connected with a reference voltage output end REF of the linear control chip U1; the other end of the fifth resistor R5 is respectively connected with one end R6 of the sixth resistor and an adjusting end VSET of the linear control chip U1; the other end of the sixth resistor R6 is grounded; the adjustment terminal VSET is configured to adjust the reference voltage output by the reference voltage output terminal REF.
In an embodiment of the present invention, the reference voltage output terminal REF of the linear control chip U1 is configured to output a reference voltage, and the voltage division of the reference voltage can be achieved and more stable through the arrangement of different resistance ratios of the fifth resistor R5 and the sixth resistor R6.
Further, the linear control chip U1 further includes a voltage adjustment output terminal FB; the voltage adjustment output terminal FB is respectively connected to the third terminal of the switching element TR1 and one terminal of the third resistor R3 in any of the lines, so as to make the input current on each of the lines and the control branch connected thereto more stable.
In an embodiment of the present invention, the voltage adjustment output FB is connected to the third resistor R3, so that the current connected to one path of the switching element TR1 can be accurately set.
In an embodiment of the invention, the reference voltage output terminal REF, the adjustment terminal VSET, and the voltage adjustment output terminal FB of the linear control chip U1 are matched with each other. The reference voltage output by the reference voltage output end REF is adjusted by setting the ratio of the resistance values of the fifth resistor R5 and the sixth resistor R6, so that the adjustment end VSET is adjusted, and the voltage adjustment output end FB outputs the reference voltage adjusted by the adjustment end VSET to the third resistor R3, so that the current on each line including the LED lamp set and the control branch connected thereto is more stable.
In an embodiment of the present invention, when the open protection of the LED driving circuit is started, the detection end VF detects an open signal and feeds the open signal back to the control end OUT, the control end OUT outputs an open command to the second end of the switching element TR1 of each circuit, and after receiving the open command, the first end and the third end of each switching element TR1 are disconnected, so as to achieve that all LED lamp groups are turned off, so that the input current is constantly smaller than a certain current value, such as constantly smaller than the maximum current 10mA specified by the regulations.
Generally, under a certain input voltage range and a certain high and low temperature environment temperature condition, the input current is required to meet a minimum current which is constantly greater than the regulation rule when the driving circuit is in normal operation, or the input current is required to meet a maximum current which is constantly less than the regulation rule when the open circuit protection of the driving circuit is started.
For example, the input voltage is 9V-16V, the high-low temperature environment temperature is-40-85 ℃, the minimum current required to meet the rule is 65mA when the driving circuit works normally, or the maximum input current required to meet the rule is 10mA when the open circuit protection of the driving circuit starts.
In an embodiment of the invention, any one or more of the above-mentioned LED lamp sets are replaced by resistors as compensation circuits for ensuring that the input current is constantly greater than the minimum operating current specified by the regulations during normal operation. Meanwhile, when an open circuit occurs, the input current of each path can be quite stable and smaller than a certain current value. Therefore, in an embodiment of the present invention, under a certain input voltage range and a certain high-low temperature environment temperature condition, the present invention can meet the requirement that the input current is constantly greater than the minimum current specified by the regulation when the driving circuit is in normal operation, or the input current meets the requirement that the input current is constantly less than the maximum current specified by the regulation when the open-circuit protection of the driving circuit is started.
In an embodiment of the invention, the device further comprises a filter circuit connected with the DC-DC constant voltage driving module; the filter circuit includes: the second diode D2, the inductor L1, the first capacitor C1 and the second capacitor C2; the anode of the second diode D2 is connected with external voltage; the cathode of the second diode D2 is connected with one end of the inductor L1 and one end of the first capacitor C1 respectively; the other end of the inductor L1 is connected with the input end of the DC-DC constant voltage driving module and one end of the second capacitor C2 respectively; the other end of the first capacitor C1, the other end of the second capacitor C2 and the grounding end of the DC-DC constant voltage driving module are grounded respectively.
In an embodiment of the present invention, the second diode D2 mainly plays a role in reverse connection protection, and can effectively protect the back-end circuit when the power supply terminal is connected in reverse connection with the anode and the cathode.
In an embodiment of the present invention, the first capacitor C1, the second capacitor C2 and the inductor L1 have filtering effects, mainly for effectively suppressing electromagnetic interference of the circuit.
In one embodiment of the present invention, the DC-DC constant voltage driving module may be reduced from 9V-16V to a smaller constant voltage, thereby improving system efficiency.
On the basis of meeting the input voltage stability of the parallel multi-path LED lamp set, the system efficiency of the circuit can be greatly improved.
For example, the voltage of the automobile storage battery is reduced to about 6V, power is supplied to the rear-end multi-path LED lamp strings and the linear control chip, the LED lamp strings select 2 LED lamp strings, the single voltage drop is 2V, the total voltage division on the LED lamp strings is 4V, and the voltage division of the rear-end linear control chip is 2V. Thus, the efficiency of the back-end system reaches 67% (4/6), and the efficiency of the front-end DC-DC is generally over 90%, so that the total system efficiency is over 60%.
If the main current method of the car lamp, namely the pure linear constant-current type or the resistance type driving, is adopted, the system efficiency is only 25 percent when the voltage of the storage battery reaches 16V. If the DC-DC constant current type driving is adopted, the system efficiency is about 80%, but the system cost is greatly increased compared with the invention. Therefore, the DC-DC and linear combination LED driving circuit provided by the invention has obvious progress.
Fig. 3 is a schematic flow chart of an LED driving method according to an embodiment of the invention. As shown, the LED driving method is applied to the DC-DC and linear combined LED driving circuit as described above, and the method includes:
step S301: an open circuit signal is detected.
In an embodiment of the present invention, the open circuit signal may be a low level signal.
Step S302: and when the open-circuit signal is detected, sending an open-circuit instruction to a signal end so as to open the switch unit.
In an embodiment of the present invention, the off command may be a low level signal.
To achieve the above and other related objects, the present invention provides a computer-readable storage medium having stored thereon an LED driving program, characterized in that the program when executed by a processor implements the LED driving method.
The computer-readable storage medium, as will be appreciated by one of ordinary skill in the art: all or part of the steps for implementing the method embodiments described above may be performed by computer program related hardware. The aforementioned computer program may be stored in a computer readable storage medium. The program, when executed, performs steps including the method embodiments described above; and the aforementioned storage medium includes: various media that can store program code, such as ROM, RAM, magnetic or optical disks.
In summary, the present invention effectively overcomes the disadvantages of the prior art and has high industrial utility value.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (10)
1. A DC-DC and linear combination LED driving circuit, comprising: the LED lamp comprises a DC-DC constant voltage driving module, a linear control chip, one or more lines containing an LED lamp group and a protection circuit;
the DC-DC constant voltage driving module includes: an input end and an output end; the input end is connected with an external power supply;
the linear control chip includes: the voltage input end, the detection end and the control end; the voltage input end is connected with the output end of the DC-DC constant voltage driving module;
one end of each circuit is connected with the output end of the DC-DC constant voltage driving module, and the other end of each circuit is grounded;
the protection circuit includes: a detection branch and a control branch corresponding to each line;
each detection branch is connected between the detection end and a detection point in the corresponding circuit so as to detect the on or off of the circuit;
each of the control branches comprises: the switch unit is arranged in the circuit, and the switch state of the switch unit is used for controlling the on or off of the circuit; the switch unit is provided with a signal end connected to the control end and is used for controlling the switch state of the switch component according to an input signal;
wherein the LED lamp group is formed by connecting one or more LED light sources in series;
any one or more LED lamp groups are replaced by resistors to be used as compensation circuits for ensuring that the input current is always larger than the minimum working current regulated by regulations during normal working.
2. The LED driver circuit of claim 1, wherein the detection branch comprises: a first diode and a first resistor; the positive electrode of the first diode is connected with the detection end of the linear control chip; the negative electrode of the first diode is respectively connected with one end of the LED lamp group in the corresponding circuit, one end of the first resistor and one end of the switch unit in the control branch; the other end of the first resistor is grounded.
3. The LED driving circuit of claim 2, wherein the switching unit comprises: a switching element, a second resistor, and a third resistor; the first end of the switching element is respectively connected with one end of the LED lamp group in the circuit, the cathode of the first diode and one end of the first resistor; the second end of the switching element is connected with one end of the second resistor; the other end of the second resistor is connected with the control end of the linear control chip; the third end of the switching element is connected with one end of the third resistor; the other end of the third resistor is grounded; the second end of the switching element is used for controlling the on-off of the first end and the third end of the switching element.
4. A DC-DC and linear combination LED driving circuit according to claim 3, wherein the switching element is an NPN triode, or a MOS transistor, or an analog switch.
5. The LED driving circuit of claim 1, further comprising a filter circuit connected to the DC-DC constant voltage driving module; the filter circuit includes: the second diode, the inductor, the first capacitor and the second capacitor;
the anode of the second diode is connected with external voltage; the negative electrode of the second diode is connected with one end of the inductor and one end of the first capacitor respectively; the other end of the inductor is connected with the input end of the DC-DC constant voltage driving module and one end of the second capacitor respectively; the other end of the first capacitor, the other end of the second capacitor and the grounding end of the DC-DC constant voltage driving module are grounded respectively.
6. The LED driver circuit of claim 1, further comprising a fourth resistor connected to the linear control chip; one end of the fourth resistor is connected with the enabling end of the linear control chip; the other end of the fourth resistor is grounded; and setting different resistance values of the fourth resistor to enable the detection end and the control end of the linear control chip to be effective or invalid.
7. The LED driving circuit of claim 3, further comprising a fifth resistor and a sixth resistor connected to the linear control chip; one end of the fifth resistor is connected with the reference voltage output end of the linear control chip; the other end of the fifth resistor is respectively connected with one end of the sixth resistor and the adjusting end of the linear control chip; the other end of the sixth resistor is grounded; the adjusting end is used for adjusting the reference voltage output by the reference voltage output end.
8. The LED driver circuit of claim 7, wherein the linear control chip further comprises a voltage adjustment output; outputting the reference voltage adjusted by the adjusting end;
the voltage regulation output end is respectively connected with a third end of the switching element and one end of the third resistor in any circuit so as to enable the input current of each circuit and the control branch connected with the circuit to be more stable.
9. An LED driving method, characterized by being applied to the DC-DC and linear combination LED driving circuit according to any one of claims 1 to 8, comprising:
detecting an open circuit signal;
and when the open-circuit signal is detected, sending an open-circuit instruction to a signal end so as to open the switch unit.
10. A computer readable storage medium having stored thereon an LED driver, wherein the LED driver, when executed by a processor, implements the LED driving method of claim 9.
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| CN201811124503.4A CN109246889B (en) | 2018-09-26 | 2018-09-26 | DC-DC and linear combination LED driving circuit, driving method thereof and storage medium |
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