CN117545129B - Method, apparatus and medium for pulse width modulation dimming of light emitting diodes - Google Patents
Method, apparatus and medium for pulse width modulation dimming of light emitting diodes Download PDFInfo
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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
- H05B45/32—Pulse-control circuits
- H05B45/325—Pulse-width modulation [PWM]
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- H—ELECTRICITY
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- 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]
- H05B45/10—Controlling the intensity of the light
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- 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
- H05B45/345—Current stabilisation; Maintaining constant current
Abstract
Embodiments of the present disclosure relate to a method, apparatus, and medium for pulse width modulation dimming of a light emitting diode, the method comprising: determining the magnitude relation between the absolute value of the rising slope and the falling slope of the inductance current of the LED driving chip; performing a periodic ramp-up operation on the inductor current during a pulse width modulation, PWM, period based on the determined magnitude relation of the absolute value of the ramp-up slope and the ramp-down slope; adjusting a slope of the inductor current variation within the pulse width modulation, PWM, period in response to the performed periodic ramp-up and ramp-down operation; and compensating for a current deviation of the output current of the LED driving chip in response to the slope of the adjusted inductor current variation. According to the method, through compensation of the output current deviation part, the dimming precision of PWM (pulse width modulation) of the LED constant current drive under the condition of low duty ratio is optimized, so that the linearity of PWM dimming is ensured, and the application scene of the constant current drive is expanded.
Description
Technical Field
Embodiments of the present disclosure relate generally to the field of LED constant current drive integrated circuits, and more particularly, to a method, apparatus, and medium for pulse width modulation dimming of light emitting diodes.
Background
Light Emitting Diode (LED) light sources are increasingly used in modern social development due to their advantages of high brightness, high luminous density, good luminous uniformity, high reliability, energy conservation, environmental protection, and the like. The LED adopts a constant current driving mode, so that the driving current can be prevented from exceeding the maximum rated value, overcurrent and overvoltage protection can be realized when lightning stroke, power grid surge and the like are suffered, the service life of equipment is prolonged, and the working reliability of the equipment is ensured.
Dimming is widely used in the field of LED lighting for energy conservation and for adjusting spatial vision. Common LED dimming methods include analog dimming and pulse width modulation (Pulse width modulation, PWM) dimming. The analog dimming can affect the color temperature and the color development effect of the LED in the dimming process, and cannot meet the scene requirement of a part of the scene requirement on the light emitting color of the LED, so the analog dimming is limited in practical application.
PWM dimming is to utilize the characteristic that human eyes are insensitive to brightness flicker, and light is emitted through high-frequency flicker, namely, pixels in a screen flicker at a higher frequency, and the persistence of vision can lead people to ignore the period of time when the pixels are dark, so that the screen always is bright in the visual sense. Because the average luminous brightness is observed by human eyes when the LED is alternately lightened and darkened, the PWM dimming can control the brightness change of a screen by adjusting the proportion of the luminous time to the extinction time in each flickering period, namely the duty ratio of PWM signals, and can linearly change the brightness of the LED without changing the working current of the LED, thereby having the advantages of wide dimming range, high precision, high efficiency, no color spectrum deviation and the like.
In a common LED constant current driving chip, a PWM signal is a rectangular wave, but in a real situation, the current cannot suddenly disappear or appear, and along with the rising and falling of the inductor current in the system, the current signal is a triangle wave with a variation, and the equivalent average value of the current signal in a flicker period is the magnitude of the output current signal. Theoretically, the larger the absolute value of the rising slope or the falling slope at the time of the inductor current change, the better the equivalent effect, otherwise, the following problems are presented:
1. when the rising slope of the inductance current is smaller, namely the inductance current rises slowly and falls quickly, the slow rising speed of the inductance current can enable the inductance current not to reach a peak value in the time corresponding to the PWM high-level signal in the process of switching the PWM pulse from the low level to the high level, so that the output current enters a steady-state mode slowly, and the equivalent average current in the period, namely the current signal output by the system, is smaller, so that the current precision in the PWM dimming process is influenced;
2. when the absolute value of the falling slope of the inductance current is smaller, namely the inductance current rises quickly and slowly, in the process of switching the PWM pulse from high level to low level, the slow falling speed of the inductance current can enable the inductance current not to fall to zero in the time corresponding to the PWM low level signal, so that extra current value interference exists in a complete PWM dimming period, and the equivalent average current in the period, namely the current signal output by the system, is larger, thereby influencing the PWM dimming precision.
In summary, the conventional PWM dimming scheme has a problem of dimming accuracy due to a large output current deviation, and optimization is needed.
Disclosure of Invention
In view of the above problems, the present disclosure provides a method, a computing device, and a computer readable storage medium for pulse width modulation dimming of a light emitting diode, which can solve the current deviation problem in the current dimming scheme, and ensure that the ratio of an average current signal to an initial current signal output after dimming is the same as the duty ratio of the pulse width modulation signal as much as possible. According to the technical scheme, the dimming precision of PWM (pulse width modulation) under the condition of low duty ratio of LED constant current driving is optimized, so that the linearity of PWM dimming is guaranteed, and the application scene of constant current driving is expanded.
According to a first aspect of the present disclosure, there is provided a method for pulse width modulation dimming of a light emitting diode, the method comprising: determining the magnitude relation between the absolute value of the rising slope and the falling slope of the inductance current of the LED driving chip; performing a periodic ramp-up operation on the inductor current during a pulse width modulation, PWM, period based on the determined magnitude relation of the absolute value of the ramp-up slope and the ramp-down slope; adjusting a slope of the inductor current variation within the pulse width modulation, PWM, period in response to the performed periodic ramp-up and ramp-down operation; and compensating for a current deviation of the output current of the LED driving chip in response to the slope of the adjusted inductor current variation.
According to a second aspect of the present disclosure, there is provided a computing device comprising: at least one processor; and a memory communicatively coupled to the at least one processor; the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of the first aspect of the present disclosure.
In a third aspect of the present disclosure, there is provided a non-transitory computer-readable storage medium storing computer instructions for causing a computer to perform the method of the first aspect of the present disclosure.
In some embodiments, determining the magnitude relationship of the absolute value of the rising slope and the falling slope of the inductor current driving the chip includes: collecting a change signal of inductance current in a complete pulse width modulation period; calculating the rising slope and the falling slope of the inductance current based on the collected change signals; and comparing the absolute value of the rising slope and the falling slope of the calculated inductance current, thereby determining the magnitude relation of the absolute value of the rising slope and the falling slope.
In some embodiments, determining the magnitude relationship of the absolute value of the rising slope and the falling slope of the inductor current driving the chip further comprises: determining that a current signal of an output current at a current moment in the pulse width modulation period is large in response to an absolute value of a rising slope of the inductance current being larger than a falling slope, and performing reverse current compensation on the output current; and determining that the current signal of the output current at the moment in the pulse width modulation period is smaller in response to the absolute value that the rising slope of the inductance current is smaller than the falling slope, and performing forward current compensation on the output current.
In some embodiments, performing a periodic ramp-up operation on the inductor current during a pulse width modulation period comprises: a plurality of peak detection voltages that rise continuously are set for an inductor current that rises during a pulse width modulation period, so that the inductor current realizes a plurality of secondary rises during the rise during the pulse width modulation period.
In some embodiments, performing a periodic ramp-up operation on the inductor current during a pulse width modulation period further comprises: for the set continuously rising peak detection voltage, the slope at which the peak detection voltage continuously rises is set to be equal to the absolute value of the falling slope of the falling inductor current determined in the pulse width modulation period.
In some embodiments, performing a periodic ramp-up operation on the inductor current during a pulse width modulation period further comprises: a plurality of peak detection voltages which continuously decrease are set for the inductor current which decreases in the pulse width modulation period, so that the inductor current realizes a plurality of secondary steps in the decreasing process in the pulse width modulation period.
In some embodiments, performing a periodic ramp-up operation on the inductor current during a pulse width modulation period further comprises: for the set continuously decreasing peak detection voltage, the absolute value of the slope at which the peak detection voltage continuously decreases is set to be equal to the rising slope of the rising inductor current determined in the pulse width modulation period.
In some embodiments, adjusting the slope of the inductor current variation over the pulse width modulation period comprises: the slope of the adjusted inductor current variation is set to be equal to the slope of the continuously varying peak detection voltages.
It should be noted that, when referring to the words lifting and lowering, the present disclosure is merely to express the actions of lifting and lowering, and one lifting process and one lowering process are included in one complete period, which are independent of the ascending and descending sequence.
And a plurality of small rising and falling periods of the inductive current are introduced in the falling process of the inductive current of the PWM pulse period, so that the excessively low average current is subjected to forward compensation, and the current precision and the dimming linearity in the PWM dimming process are ensured.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following specification.
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The above and other features, advantages and aspects of embodiments of the present disclosure will become more apparent by reference to the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements.
Fig. 1 shows a schematic diagram of a system for implementing a method for pulse width modulation dimming of a light emitting diode according to an embodiment of the present disclosure.
Fig. 2 shows a flowchart of a method for pulse width modulation dimming of a light emitting diode according to an embodiment of the present disclosure.
Fig. 3 illustrates a rising slope compensated PWM dimming timing waveform diagram according to an embodiment of the present disclosure.
Fig. 4 illustrates a falling slope compensated PWM dimming timing waveform diagram according to an embodiment of the present disclosure.
Fig. 5 shows a block diagram of an electronic device according to an embodiment of the disclosure.
Detailed Description
Exemplary embodiments of the present disclosure are described below in conjunction with the accompanying drawings, which include various details of the embodiments of the present disclosure to facilitate understanding, and should be considered as merely exemplary. Accordingly, one of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the present disclosure. Also, descriptions of well-known functions and constructions are omitted in the following description for clarity and conciseness.
The term "comprising" and variations thereof as used herein means open ended, i.e., "including but not limited to. The term "or" means "and/or" unless specifically stated otherwise. The term "based on" means "based at least in part on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment. The term "another embodiment" means "at least one additional embodiment". The terms "first," "second," and the like, may refer to different or the same object. Other explicit and implicit definitions are also possible below.
As described above, when the inductor current of the LED driving chip rises or falls slowly and the input PWM signal has a low duty ratio, the conventional PWM dimming method inevitably has a problem of larger or smaller average current in the period, which affects the current precision in the PWM dimming process, and further affects the LED dimming effect, and cannot meet the scene application of more and more LED high lighting requirements.
To at least partially address one or more of the above problems, as well as other potential problems, example embodiments of the present disclosure propose a method for pulse width modulation dimming of a light emitting diode. The absolute values of the rising slope and the falling slope of the inductance current are identified through the chip system, the smaller value is taken as a reference, the changing peak detection voltage is matched, the inductance current change slope corresponding to the larger value is adjusted to be the same as the reference, and therefore compensation of an output current deviation part is achieved, and further current precision and dimming linearity in a PWM dimming process are guaranteed.
Fig. 1 shows a schematic diagram of a system for implementing a method for pulse width modulation dimming of a light emitting diode according to an embodiment of the present invention. As shown in fig. 1, the system includes a computing device 110, a current signal data management device 130, and a network 140. The computing device 110, the current signal data management device 130 may interact with data via a network 140 (e.g., the internet).
The current signal data management device 130 may store, for example, current signal data of one or more LED driver chips. The current signal data management device 130 may also send the stored current signal data to the computing device 110. The current signal data management device is for example, but not limited to: an electronic computer, a network server, a storage calculator, etc. The current signal data management device 130, for example, collects current signal data from a plurality of LED driving chips, and may sort and manage the collected current signal data of one or more LED driving chips.
With respect to the computing device 110, it is for example used to obtain current signal data from the current signal data management device 130; and further informationizing the acquired current signal data. The computing device 110 may also generate a plurality of visual graphical presentation current signal data based on the informative current signal data. The current signal data can be screened and trained by adjusting the visual pattern for displaying the current signal data. The computing device 110 may receive text data from a user or the current signal data management device 130. By applying the method provided by the invention, the computing equipment 110 can carry out high-precision PWM dimming on the chip in the LED constant current driving field.
Computing device 110 may have one or more processing units, including special purpose processing units such as GPUs, FPGAs, ASICs, and the like, as well as general purpose processing units such as CPUs. In addition, one or more virtual machines may also be running on each computing device 110. In some embodiments, the computing device 110 and the current signal data management device 130 may be integrated together or may be separate from each other. In some embodiments, computing device 110 includes, for example, a current signal acquisition and storage unit 112, a current signal data processing unit 114, and a current signal change rate adjustment unit 116.
A current signal acquisition and storage unit 112, the current signal acquisition and storage unit 112 being configured to acquire a varying signal of the inductor current over one complete pulse width modulation PWM period.
A current signal data processing unit 114, wherein the current signal data processing unit 114 is configured to calculate a rising slope and a falling slope of the inductor current based on the collected change signal, and compare the calculated absolute values of the rising slope and the falling slope of the inductor current, thereby determining a magnitude relation of the absolute values of the rising slope and the falling slope.
According to the absolute value magnitude relation of the rising slope and the falling slope of the inductance current, the accuracy condition of the current output current is identified: when the rising slope of the inductance current is larger than the absolute value of the falling slope, determining that the current signal of the output current at the moment in the Pulse Width Modulation (PWM) period is larger, and performing reverse compensation on the output current; when the rising slope of the inductor current is smaller than the absolute value of the falling slope, the current signal of the output current at the moment in the pulse width modulation PWM period is determined to be smaller, and forward compensation needs to be performed on the output current.
A current signal change speed adjustment unit 116, wherein the current signal change speed adjustment unit 116 is configured to perform a periodic lifting operation on the inductor current in a pulse width modulation PWM period based on a magnitude relation of the absolute value of the determined rising slope and falling slope (i.e. the accuracy of the current output by the LED driving chip).
The secondary periodic rising or falling of the inductance current is carried out in the rising or falling process of the pulse width modulation PWM period, so that the rising slope or falling slope of the inductance current is changed, the average current value of the equivalent output is also changed, and the action of fluctuation of the output current is essentially to compensate the current deviation of the output current of the LED driving chip.
Fig. 2 shows a flowchart of a method for pulse width modulation dimming of a light emitting diode according to an embodiment of the present disclosure. The method may be performed by the computing device 110 as shown in fig. 1, or at the electronic device 300 as shown in fig. 5. It should be understood that the method may also include additional blocks not shown and/or that the blocks shown may be omitted, the scope of the disclosure being not limited in this respect.
When the LED driving chip works, a current signal of a load LED is converted into a voltage signal through the sampling resistor, and the voltage signal is cooperated with the power switch and the inductor through the inner loop feedback control system, so that constant current output of the LED is realized. In the PWM dimming process, a PWM signal is introduced through a peripheral chip pin to control a power switch, so that the brightness adjustment of the LED is realized through a high-frequency switch.
At step 202, computing device 110 may collect a signal of a change in inductor current over a complete pulse width modulation PWM period.
The varying signal of the inductor current in a complete PWM period includes electrical signal data during the current rise from zero to peak, the current in a high steady state mode, the current drop from peak to zero, the current in a low level, etc.
At step 204, the computing device 110 may calculate a rising slope and a falling slope of the inductor current based on the collected change signal.
After the inductor current passes through a complete PWM pulse period, all the collected electric signal data are counted in the chip, and the rising slope of the inductor current in the process of converting from low level to high level and the falling slope of the inductor current in the process of converting from high level to low level are calculated respectively.
At step 206, computing device 110 may compare the absolute value of the calculated rising and falling slopes of the inductor current to determine a magnitude relationship of the absolute values of the rising and falling slopes.
By judging the relation between the rising slope and the absolute value of the falling slope of the inductance current, the specific deviation condition of the current output current can be further identified, and further, the basis is provided for the follow-up current compensation operation:
when the rising slope of the inductance current is larger than the absolute value of the falling slope, determining that the current signal of the output current at the moment in the Pulse Width Modulation (PWM) period is larger, and performing reverse compensation on the output current; when the rising slope of the inductor current is smaller than the absolute value of the falling slope, the current signal of the output current at the moment in the pulse width modulation PWM period is determined to be smaller, and forward compensation needs to be performed on the output current.
At step 208, the computing device 110 may perform a periodic ramp-up operation on the inductor current during the PWM period based on the determined magnitude relation of the absolute value of the ramp-up slope and the ramp-down slope (i.e., the deviation of the current output current of the LED driver chip), thereby adjusting the slope of the inductor current change during the PWM period.
After a complete PWM pulse period has ended, the system inside the chip recognizes that the rising slope of the inductor current is too high and the absolute value of the falling slope is too low, and determines that this situation may result in an overall higher output load current. At this time, the chip sets a plurality of continuously raised reference voltages as peak detection voltages for the inductor current raised in the pulse width modulation PWM period, so that the inductor current realizes a plurality of secondary raising and lowering in the raising process in the pulse width modulation PWM period, that is, a plurality of raising and lowering small periods are introduced; and setting the rising slope of the peak detection voltage when the peak detection voltage continuously changes to be equal to the absolute value of the falling slope of the inductance current read by the chip in the pulse width modulation PWM period.
Similarly, after a complete PWM pulse period has ended, the system within the chip recognizes that the rising slope of the inductor current is too low and the absolute value of the falling slope is too high, and determines that this situation may result in an overall lower output load current. At this time, the chip sets a plurality of reference voltages which are continuously reduced as peak detection voltages for the inductor current which is reduced in the pulse width modulation PWM period, so that the inductor current is secondarily lifted for a plurality of times in the process of reducing in the pulse width modulation PWM period, namely, a plurality of lifting small periods are introduced; and setting the absolute value of the falling slope of the peak detection voltage when the peak detection voltage continuously changes to be equal to the rising slope of the inductance current read by the chip in the pulse width modulation PWM period.
For the small lifting period, the inductor current is required to complete a complete lifting and falling process every time the inductor current passes through the small lifting period, and the change slope of the inductor current in the small lifting period is the same as the change slope of the original inductor current in the PWM pulse period.
In step 210, a current deviation of the output current of the LED driving chip is compensated in response to the slope of the adjusted inductor current variation.
The rising and falling processes of the inductance current are continuously repeated before the inductance current reaches a steady state, so that the rising speed of the inductance current is slowed down, the rapidly rising inductance current is reversely compensated, the average current output by the chip is reduced, and the PWM dimming precision is improved.
The rising and falling processes are continuously repeated before the inductor current is reduced to zero, so that the falling speed of the inductor current is slowed down, forward compensation is performed on the inductor current which is rapidly reduced, average current output by a chip is provided, and PWM dimming precision is improved.
Applying the method, fig. 3 shows a rising slope compensated PWM dimming timing waveform diagram according to an embodiment of the present disclosure, and fig. 4 shows a falling slope compensated PWM dimming timing waveform diagram according to an embodiment of the present disclosure. It should be understood that fig. 3 and 4 are merely illustrative and are not intended to limit the specific operations of the disclosed methods.
Referring to fig. 3, a rising slope in the PWM dimming method of the LED constant current driving is compensated. In fig. 3, PWM represents a pulse width modulation period curve, and ILOAD represents an output current curve of the LED. In the first period of PWM dimming, the chip firstly reads the rising slope and the falling slope of the inductance current, and confirms that the rising slope is higher and the absolute value of the falling slope is lower, and at the moment, the equivalent average value of the load current in one pulse period is higher than the pulse value (the area surrounded by the current signal change lines is larger). And generating a reference voltage which has the same slope and continuously rises by taking the absolute value of the falling slope of the inductor current as a reference, wherein the reference voltage is used for detecting the peak value turn-off in the rising process of the inductor current.
And a plurality of small rising and falling periods of the inductive current are introduced in the rising process of the inductive current of the PWM pulse period, so that the overhigh average current is reversely compensated, and the current precision and the dimming linearity in the PWM dimming process are ensured.
Referring to fig. 4, a falling slope in the PWM dimming method of the LED constant current driving is compensated. In fig. 4, PWM represents a pulse width modulation period curve, and ILOAD represents an output current curve of the LED. In the first period of PWM dimming, the chip firstly reads the rising slope and the falling slope of the inductance current, and confirms that the rising slope is lower and the absolute value of the falling slope is higher, and at the moment, the equivalent average value of the load current in one pulse period is lower than the pulse value (the area surrounded by the current signal change line is smaller). And generating a reference voltage which has the same absolute value slope and continuously decreases by taking the rising slope of the inductor current as a reference, and detecting peak value turn-off in the falling process of the inductor current.
And a plurality of small rising and falling periods of the inductive current are introduced in the falling process of the inductive current of the PWM pulse period, so that the excessively low average current is subjected to forward compensation, and the current precision and the dimming linearity in the PWM dimming process are ensured.
Fig. 5 shows a schematic block diagram of an example electronic device 300 that may be used to implement embodiments of the present disclosure. For example, computing device 110 as shown in FIG. 1 may be implemented by electronic device 300. As shown in fig. 5, the electronic device 300 includes a central processing unit 301 (CPU) that can perform various suitable actions and processes according to computer program instructions stored in a read only memory 302 (ROM) or computer program instructions loaded from a storage unit 308 into a random access memory 303 (RAM). In the random access memory 303 (RAM), various programs and data required for the operation of the electronic device 300 may also be stored. A central processing unit 301 (CPU), a read only memory 302 (ROM), and a random access memory 303 (RAM) are connected to each other through a bus 304. An input/output interface 305 (I/O) is also connected to bus 304.
Various components in the electronic device 300 are connected to an input/output interface 305 (I/O), including: an input unit 306 such as a keyboard, mouse, microphone, etc.; an output unit 307 such as various types of displays, speakers, and the like; a storage unit 308 such as a magnetic disk, an optical disk, or the like; and a communication unit 309 such as a network card, modem, wireless communication transceiver, etc. The communication unit 309 allows the device 300 to exchange information/data with other devices via a computer network such as the internet and/or various telecommunication networks.
The various procedures and processes described above, such as methods, may be performed by central processing unit 301 (CPU). For example, in some embodiments, the method may be implemented as a computer software program tangibly embodied on a machine-readable medium, such as the storage unit 308. In some embodiments, part or all of the computer program may be loaded and/or installed onto device 300 via read only memory 302 (ROM) and/or communication unit 309. One or more actions of the methods described above may be performed when a computer program is loaded into random access memory 303 (RAM) and executed by central processing unit 301 (CPU).
The present disclosure relates to methods, apparatus, systems, electronic devices, computer readable storage media, and/or computer program products. The computer program product may include computer readable program instructions for performing various aspects of the present disclosure.
The computer readable storage medium may be a tangible device that can hold and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium would include the following: portable computer disks, hard disks, random Access Memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static Random Access Memory (SRAM), portable compact disk read-only memory (CD-ROM), digital Versatile Disks (DVD), memory sticks, floppy disks, mechanical coding devices, punch cards or in-groove structures such as punch cards or grooves having instructions stored thereon, and any suitable combination of the foregoing. Computer-readable storage media, as used herein, are not to be construed as transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., optical pulses through fiber optic cables), or electrical signals transmitted through wires.
The computer readable program instructions described herein may be downloaded from a computer readable storage medium to a respective computing/processing device or to an external computer or external storage device over a network, such as the internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, fiber optic transmissions, wireless transmissions, routers, firewalls, switches, gateway computers and/or edge computing devices. The network interface card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium in the respective computing/processing device.
Computer program instructions for performing the operations of the present disclosure can be assembly instructions, instruction Set Architecture (ISA) instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, c++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer readable program instructions may be executed entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computer (for example, through the Internet using an Internet service provider). In some embodiments, aspects of the present disclosure are implemented by personalizing electronic circuitry, such as programmable logic circuitry, field Programmable Gate Arrays (FPGAs), or Programmable Logic Arrays (PLAs), with state information of computer readable program instructions, which can execute the computer readable program instructions.
Various aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer-readable program instructions.
These computer readable program instructions may be provided to a processing unit of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processing unit of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable medium having the instructions stored therein includes an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.
The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer, other programmable apparatus or other devices implement the functions/acts specified in the flowchart and/or block diagram block or blocks.
The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
The foregoing description of the embodiments of the present disclosure has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the technical improvements in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
Claims (7)
1. A method for pulse width modulation dimming of a light emitting diode, the method comprising:
determining the magnitude relation between the rising slope and the absolute value of the falling slope of the inductance current of the light-emitting diode driving chip, wherein the magnitude relation comprises the steps of determining that the current signal of the output current at the current moment in the pulse width modulation period is larger in response to the fact that the rising slope of the inductance current is larger than the absolute value of the falling slope, performing reverse current compensation on the output current, and determining that the current signal of the output current at the moment in the pulse width modulation period is smaller in response to the fact that the rising slope of the inductance current is smaller than the absolute value of the falling slope, and performing forward current compensation on the output current;
performing a periodic ramp-up operation on the inductor current during a pulse width modulation period based on the determined magnitude relation of the absolute value of the ramp-up slope and the ramp-down slope, wherein the periodic ramp-up operation comprises setting a plurality of peak detection voltages which are continuously increased for the inductor current which is increased during the pulse width modulation period so that the inductor current is secondarily increased a plurality of times during the ramp-up period, and setting a plurality of peak detection voltages which are continuously decreased for the inductor current which is decreased during the pulse width modulation period so that the inductor current is secondarily increased a plurality of times during the ramp-down period;
adjusting a slope of the inductor current variation over the pulse width modulation period in response to the performed periodic ramp-up operation;
and responding to the slope of the regulated inductance current change, and performing current compensation on the current deviation of the output current of the light-emitting diode driving chip.
2. The method of claim 1, wherein determining the magnitude relationship of the absolute value of the rising slope and the falling slope of the inductor current driving the chip comprises:
collecting a change signal of inductance current in a complete pulse width modulation period;
calculating the rising slope and the falling slope of the inductance current based on the collected change signals;
and comparing the absolute value of the rising slope and the falling slope of the calculated inductive current, thereby determining the magnitude relation of the absolute value of the rising slope and the falling slope.
3. The method of claim 1, wherein performing a periodic ramp-up operation on the inductor current during a pulse width modulation period further comprises:
for the set continuously rising peak detection voltage, the slope at which the peak detection voltage continuously rises is set to be equal to the absolute value of the falling slope of the falling inductor current determined in the pulse width modulation period.
4. The method of claim 1, wherein performing a periodic ramp-up operation on the inductor current during a pulse width modulation period further comprises:
for the set continuously decreasing peak detection voltage, the absolute value of the slope at which the peak detection voltage continuously decreases is set to be equal to the rising slope of the rising inductor current determined in the pulse width modulation period.
5. The method of claim 1, wherein adjusting the slope of the inductor current variation over the pulse width modulation period comprises:
the slope of the adjusted inductor current variation is set to be equal to the slope of the continuously varying peak detection voltages.
6. A computing device, comprising:
at least one processor; and
a memory communicatively coupled to the at least one processor;
the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-5.
7. A non-transitory computer readable storage medium storing computer instructions, wherein the computer instructions are for causing the computer to perform the method of any one of claims 1-5.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101902851A (en) * | 2009-05-25 | 2010-12-01 | 皇家飞利浦电子股份有限公司 | Light-emitting diode driving circuit |
| CN105356743A (en) * | 2015-05-26 | 2016-02-24 | 成都芯源系统有限公司 | Step-up and step-down switching power converter and control circuit thereof |
| CN113852431A (en) * | 2021-11-29 | 2021-12-28 | 罗森伯格技术有限公司 | Method, communication device and storage medium for determining pilot power |
| CN114639342A (en) * | 2022-04-25 | 2022-06-17 | 北京欧铼德微电子技术有限公司 | Display panel brightness control method and device, display equipment and electronic equipment |
| CN116367377A (en) * | 2022-12-29 | 2023-06-30 | 杰华特微电子股份有限公司 | Switching power supply for driving LED and control method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP4162597A1 (en) * | 2020-06-04 | 2023-04-12 | Aethera Technologies Limited | Rf power source with improved galvanic isolation |
-
2024
- 2024-01-09 CN CN202410031126.9A patent/CN117545129B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101902851A (en) * | 2009-05-25 | 2010-12-01 | 皇家飞利浦电子股份有限公司 | Light-emitting diode driving circuit |
| CN105356743A (en) * | 2015-05-26 | 2016-02-24 | 成都芯源系统有限公司 | Step-up and step-down switching power converter and control circuit thereof |
| CN113852431A (en) * | 2021-11-29 | 2021-12-28 | 罗森伯格技术有限公司 | Method, communication device and storage medium for determining pilot power |
| CN114639342A (en) * | 2022-04-25 | 2022-06-17 | 北京欧铼德微电子技术有限公司 | Display panel brightness control method and device, display equipment and electronic equipment |
| CN116367377A (en) * | 2022-12-29 | 2023-06-30 | 杰华特微电子股份有限公司 | Switching power supply for driving LED and control method |
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