CN110213855B - Exponential dimming method and system for light emitting diode - Google Patents
Exponential dimming method and system for light emitting diode Download PDFInfo
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Abstract
The invention discloses an index dimming method and system of a light emitting diode, comprising the following steps: obtaining a dimming control code of Nbit; all the numbers are judged, and when the ith number is 1, the corresponding coefficient of the ith number is obtained to be [ (I)max/Imin)^(1/codemax)]^ (2^ i), and obtaining a corresponding coefficient of 1 when the number is 0; according to formula IDac＝IComputingCalculating to obtain regulating current (corresponding coefficient of the No. N-1 digit of the No. zero digit of the No. C); and dimming the light emitting diode according to the adjusting current. In combination with formula IDac＝IComputingThe dimming control coding of Nbit can be obtained by multiplying the coefficients for N times, the dimming method is simpler, less hardware resources can be occupied, and the precision of the dimming current is higher.
Description
Technical Field
The invention relates to the technical field of dimming, in particular to an exponential dimming method and system of a light emitting diode.
Background
With the popularization of LED (Light Emitting Diode) lighting applications, the development of LED driving and dimming technologies is also changing day by day. At present, in the aspect of LED backlight dimming, more and more LED driving chips adopt an exponential dimming curve, compared with a linear dimming curve, because the brightness change of the exponential dimming curve can make human eyes obtain more comfortable experience and feeling when the brightness is low. The common exponential dimming methods are analog and digital, and an analog circuit can realize exponential dimming through a corresponding analog device such as a diode, but the precision and the stability of the analog dimming method are far lower than those of a digital circuit.
At present, the method for realizing LED index dimming through a digital circuit mainly includes: table lookup, piecewise linear, and iterative methods. The lookup table method can artificially set the dimming brightness codes to form a set dimming curve; for example, when the lookup table method is used in the exponential dimming, taking dimming with 11bit resolution as an example, the mapping manner of the exponent can be adopted to map 1 to 2047 representing the dimming control code to the calculated value of a certain a ^ x function, so that an approximate exponential dimming curve is artificially created. Piecewise linearity can utilize multi-segment linearity to fit an exponential curve to realize exponential dimming; also for example, with 11bit resolution dimming, a 256-segment linear approximation can be used to get the resulting curve closer and closer to the target function curve. The iteration method carries out iteration multiplication on the base number for specified times through a multiplier to realize exponential dimming; for example, when x is 2, y is calculated by a multiplier, and a period of multiplication is needed to obtain a result; when x is 100, y is calculated by a multiplier a 100, and the result needs to be obtained by 99 cycles of multiplication. The existing LED index dimming method is complex.
Disclosure of Invention
In view of this, the present invention provides an exponential dimming method and system for a light emitting diode, which effectively solve the problems in the prior art.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
an exponential dimming method of a light emitting diode, comprising:
obtaining a dimming control code of Nbit, wherein the dimming control code comprises an N-1 th code to a zero number which are sequentially arranged, and N is an integer not less than 2;
all the numbers are judged, and when the ith number is 1, the corresponding coefficient of the ith number is obtained to be [ (I)max/Imin)^(1/codemax)]^ (2^ I) and obtaining a corresponding coefficient of 1 when the code is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminBeing said light-emitting diodeMinimum drive current, codemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1;
according to formula IDac＝IComputingCalculating to obtain regulating current (corresponding coefficient of N-1 th digit of zero digit of N-1), wherein IDacFor the regulation of current, IComputingIs reference IminCalculating the obtained current value;
and dimming the light emitting diode according to the adjusting current.
Optionally, the digital coefficient is a pre-stored coefficient code, where obtaining the dimming control code of Nbit includes:
all the numbers are judged, and when the ith number is 1, the corresponding coefficient of the ith number is obtained to be [ (I)max/Imin)^(1/codemax)](2^ I) and obtaining coefficient code corresponding to coefficient 1 when the number is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1;
according to formula Dac _ code ═ IComputingThe code (the corresponding coefficient code of the N-1 th code, the corresponding coefficient code of the zero number) is calculated to obtain the exponential transformation code, wherein Dac _ code is the exponential transformation code, IComputingIs (I)min/IFixing)，IFixingThe minimum current source of the digital-to-analog converter is controlled to be a fixed value;
and converting the index conversion code into an adjusting current through the digital-to-analog converter, and dimming the light emitting diode according to the adjusting current.
Optionally, the calculating to obtain the exponent transform code includes:
judging the digital code and acquiring corresponding coefficient codes, calculating j-th intermediate index conversion codes according to a formula Dac _ code _ j (Dac _ code _ j-1) j-th corresponding coefficient codes, wherein Dac _ code _ j is the j-th intermediate index conversion codeDac _ code _ j-1 is the j-1 th intermediate exponent conversion code, and the first intermediate exponent conversion code is IComputingThe code of (1) is an integer of which j is more than 1 and not more than N;
until the last coefficient code is calculated according to the calculation rule to obtain the index conversion code.
Optionally, the determining all the numbers is:
and judging all the numbers according to a preset rule.
Optionally, the preset rule is an order from the N-1 th digit to the zeroth digit.
Correspondingly, the invention also provides an exponential dimming system of the light emitting diode, which comprises:
the register module is used for acquiring a dimming control code of Nbit, wherein the dimming control code comprises an N-1 th digit to a zero digit which are sequentially arranged, and N is an integer not less than 2; and judging all the numbers, and obtaining the corresponding coefficient of the ith number as [ (I) when the ith number is 1max/Imin)^(1/codemax)]^ (2^ I) and obtaining a corresponding coefficient of 1 when the code is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1;
a calculation module according to formula IDac＝IComputingCalculating to obtain regulating current (corresponding coefficient of N-1 th digit of zero digit of N-1), wherein IDacFor the regulation of current, IComputingIs reference IminCalculating the obtained current value;
and the dimming module is used for dimming the light emitting diode according to the adjusting current.
Optionally, the digital coefficient is a coefficient code pre-stored in a coefficient memory, wherein the register module is configured to obtain Nbit dimming controlMaking codes; and judging all the numbers, and obtaining the corresponding coefficient of the ith number as [ (I) when the ith number is 1max/Imin)^(1/codemax)](2^ I) and obtaining coefficient code corresponding to coefficient 1 when the number is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1;
the calculation module is a multiplier which is according to formula Dac _ code ═ IComputingThe code (the corresponding coefficient code of the N-1 th code, the corresponding coefficient code of the zero number) is calculated to obtain the exponential transformation code, wherein Dac _ code is the exponential transformation code, IComputingIs (I)min/IFixing)，IFixingThe minimum current source of the digital-to-analog converter is controlled to be a fixed value;
the light adjusting module is the digital-to-analog converter, converts the index conversion code into adjusting current through the digital-to-analog converter, and adjusts light of the light emitting diode according to the adjusting current.
Optionally, the register module includes a first register and a second register;
the first register is used for judging all the numbers after acquiring the dimming control code of the Nbit, wherein after judging one number and acquiring the corresponding coefficient code, the first register controls the corresponding coefficient code to be output to the multiplier;
the multiplier calculates j-th intermediate index conversion codes according to a formula Dac _ code _ j-Dac _ code _ j-1 j corresponding coefficient codes of j-th number, and transmits the j-th intermediate index conversion codes to the second register for registering, wherein Dac _ code _ j is the j-th intermediate index conversion codes, Dac _ code _ j-1 is the j-1-th intermediate index conversion codes transmitted to the multiplier by the second register for registering, and the first intermediate index conversion codes are I codesComputingThe code of the corresponding coefficient of the initial judgment digital code until the last coefficient code is calculated according to the calculation rule to obtain the index conversion codeAnd transmitting the data to the second register for registering, wherein j is an integer which is greater than 1 and not greater than N.
Optionally, the light emitting diode index dimming system controls the number of times of calculation of the multiplier through a counter, and controls the second register to transmit the index conversion code to the digital-to-analog converter.
Optionally, the registering module judges all the numbers as follows:
and judging all the numbers according to a preset rule.
Compared with the prior art, the technical scheme provided by the invention at least has the following advantages:
the invention provides an exponential dimming method and system of a light emitting diode, comprising the following steps: obtaining a dimming control code of Nbit, wherein the dimming control code comprises an N-1 th code to a zero number which are sequentially arranged, and N is an integer not less than 2; all the numbers are judged, and when the ith number is 1, the corresponding coefficient of the ith number is obtained to be [ (I)max/Imin)^(1/codemax)]^ (2^ I) and obtaining a corresponding coefficient of 1 when the code is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1; according to formula IDac＝IComputingCalculating to obtain regulating current (corresponding coefficient of N-1 th digit of zero digit of N-1), wherein IDacFor the regulation of current, IComputingIs reference IminCalculating the obtained current value; and dimming the light emitting diode according to the adjusting current.
From the above, it can be seen that formula I is combinedDac＝IComputingThe technical scheme provided by the invention can obtain the adjusting current only through multiplication calculation of the N times of coefficients for the dimming control code of Nbit, thereby achieving the aim of dimming the light-emitting diode, and the dimming method is simpler and can occupy less hardware resourcesThe source ensures higher precision of the dimming current.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a flowchart of an exponential dimming method for a light emitting diode according to an embodiment of the present disclosure;
fig. 2 is a flowchart of another method for exponentially dimming a light emitting diode according to an embodiment of the present disclosure;
fig. 3 is a schematic structural diagram of an exponential dimming system of a light emitting diode according to an embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of another exponential dimming system of a light emitting diode according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As described in the background art, the current methods for realizing LED index dimming through a digital circuit mainly include: table lookup, piecewise linear, and iterative methods. However, the conventional LED index dimming method is complicated.
Specifically, the look-up table method requires more hardware resources for the digital circuit, and particularly when the dimming resolution is more and more required, the hardware resources are also rapidly increased, for example, dimming with 11bit resolution has 2048 gears, and corresponding to the gear selection, the implementation circuit needs 11 × 2047 registers to construct all look-up table data, which may cause the cost of the chip to be too high. Piecewise linearity may utilize multi-piece linearity to fit an exponential curve; however, the more the segmentation is, the more the defects are approaching to the look-up table method, the more hardware resources are consumed, and when the segmentation is less, the precision of the exponential dimming curve becomes worse, so that the reduction of the segmentation is a compromise method, but a more ideal fitting effect cannot be obtained. The iteration method carries out iteration multiplication on the base number for specified times through a multiplier to realize exponential dimming; however, when the resolution is high, for example, 11 bits (i.e., the dimming control code number is 2047), 2047 iterations of multiplication are performed when the dimming control code is input to 2047, which may make the response time of the chip too long or require an extremely high frequency to guarantee.
Based on this, the embodiment of the application provides an exponential dimming method and system for a light emitting diode, which effectively solve the problems in the prior art. In order to achieve the above object, the technical solutions provided by the embodiments of the present application are described in detail below, specifically with reference to fig. 1 to 4.
Referring to fig. 1, a flowchart of an exponential dimming method of a light emitting diode according to an embodiment of the present application is shown, where the dimming method of the light emitting diode includes:
s1, obtaining a dimming control code of Nbit, wherein the dimming control code comprises N-1 th to zeroth digits which are sequentially arranged, the dimming control code is binary, and N is an integer not less than 2;
s2, judging all the numbers, and obtaining the corresponding coefficient of the ith number as [ (I) when the ith number is 1max/Imin)^(1/codemax)]^ (2^ I) and obtaining a corresponding coefficient of 1 when the code is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1;
s3, according to formula IDac＝IComputing(Nth-1 corresponding coefficient of the zero digit of the digital code), calculating to obtain the regulating current, wherein IDacFor the regulation of current, IComputingIs reference IminCalculating the obtained current value;
and S4, dimming the light emitting diode according to the adjusting current.
Understandably, in combination with formula IDac＝IComputingAccording to the technical scheme provided by the embodiment of the application, for Nbit dimming control coding, the adjusting current can be obtained only through multiplying of the N times of coefficients, and then the purpose of dimming the light emitting diode is achieved.
In an embodiment of the present application, since the conversion of the dimming control code into the regulated current can be realized by a digital circuit, coefficients and the like involved in the conversion process are all of a binary coding type. Referring to fig. 2, a flowchart of another method for exponentially dimming a light emitting diode according to an embodiment of the present disclosure is shown, where the digital coefficient is a pre-stored coefficient code, and the method for exponentially dimming a light emitting diode according to the embodiment of the present disclosure includes:
at S1, obtaining the dimming control code for Nbit includes:
s2', judging all numbers, and obtaining the corresponding coefficient of the ith number as [ (I) when the ith number is 1max/Imin)^(1/codemax)](2^ I) and obtaining a coefficient code corresponding to a coefficient of 1 when the code is 0 (i.e. keeping the product result constant), wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1;
s3' according to formula Dac _ code ═ IComputingThe code (the code of the corresponding coefficient of the N-1 th code) of the zero-th code is obtained by calculationExponent conversion code, wherein Dac _ code is the exponent conversion code, IComputingCode of (I)min/IFixing)，IFixingThe minimum current source of the digital-to-analog converter is controlled to be a fixed value;
s4', converting the index conversion code into an adjusting current through the digital-to-analog converter, and dimming the light emitting diode according to the adjusting current.
The principle of the exponential dimming provided by the embodiment of the present application is further described with reference to the exponential dimming method of the light emitting diode shown in fig. 2, wherein the following specific values are expressed in a decimal manner. Generally, the exponential dimming formula is determined by the maximum current and the minimum current, and if a finer dimming curve is desired, the number of bits (i.e., resolution) of the dimming control code needs to be as large as possible. For the dimming formula of the led, generally, there are:
Idrive the＝Imin*a^code
Wherein, IminIs the minimum current of the LED, a ═ Imax/Imin)^(1/codemax)
The mathematical principles and implementations for exponential mapping are:
for formula IDrive the＝IminA code, since the final output is an analog regulated current, there are:
Dac_code*Ifixing＝Imin*a^code
The conversion may result in:
Dac_code＝(Imin/Ifixing)*a^code
Due to IFixingThe minimum current source for the analog-to-digital converter is controlled to a fixed value. It can be seen that the core of the mapping is the a code exponential function.
Finally, for the core algorithm of exponential mapping:
the dimming control code is a binary number of Nbit, having
code[N-1:0]＝{code[N-1],code[N-2],code[N-3],···,code[1],code[0]}
When the dimming control code is converted into a decimal code, the following steps are performed:
decimal code [ N-1 ]. 2^ (N-1) + code [ N-2 ]. 2^ (N-2) +. cndot. + code [1 ]. 2^1+ code [0 ]. 2^0
For decimal a ^ code, there are:
a^code＝a^[code[N-1]*2^(N-1)]*a^[code[N-2]*2^(N-2)]*···*a^(code[1]*2^1)*a^(code[0]*2^0)
note that any one of the dimming control code codes i is a binary number whose value is not 0, i is 1, i is an integer not less than 0 and not more than N-1; thus, a code can result from up to N multiplications, each multiplication having coefficients a 2 (N-1), a 2 (N-2), a.a (2 0) in that order.
Furthermore, by using the exponential dimming method provided by the embodiment of the present application, the exponential transformation code can be obtained by multiplying the N-order coefficient code.
The following description will be given by taking the dimming control code with 11 bits (i.e. N is 11) as an example, and taking the exponential dimming curve I of the LEDDrive theThe principle and implementation of the technical solution provided by the embodiments of the present application are described by taking 100 × 1.0028^ code as an example. Wherein, Imin＝100uA，ImaxMaximum code of 30.5mA, 11bitmax＝2047。
The mathematical principles and implementations for exponential mapping are:
for formula IDrive theSince the final output is an analog regulated current, 100 × 1.0028^ code, there are:
Dac_code*Ifixing＝100×1.0028^code
The conversion may result in:
Dac_code＝100/Ifixing×1.0028^code
Due to IFixingThe minimum current source for the analog-to-digital converter is controlled to a fixed value. It can be seen that the core of the mapping is an 1.0028 code exponential function.
Finally, for the core algorithm of exponential mapping:
the dimming control code is a binary number of 11 bits, having
code[10:0]＝{code[10],code[9],code[8],···,code[1],code[0]}
When the dimming control code is converted into a decimal code, the following steps are performed:
decimal code [10 ]. 2^10+ code [9 ]. 2^9 +. cndot. + code [1 ]. cndot.2 ^1+ code [0 ]. cndot.20 pairs of decimal 1.0028^ code, have
1.0028^code＝1.0028^(code[10]*2^10)*1.0028^(code[9]*2^9)*···*1.0028^(code[1]*2^1)*1.0028^(code[0]*2^0)
Note that any one of the dimming control code codes [ i ] is a binary number whose value is not 0, i.e., 1, i is a whole number not less than 0 and not more than 10; thus, 1.0028^ code can result from up to 11 multiplications;
the coefficients multiplied each time are 1.0028^ (2^10), 1.0028^ (2^9),. cndot.. 1.0028^ (2^0) in turn, and the actual figures are shown in the following table 1:
TABLE 1
Furthermore, by using the exponential dimming method provided by the embodiment of the present application, the exponential transformation code can be obtained by multiplication of the 1-order coefficient code.
In an embodiment of the present application, when a numerical value of 1 or 0 is determined for a digital code and a coefficient code is multiplied, the multiplication may be performed once after the digital code is determined and the coefficient code is obtained, and a final exponent conversion code is finally obtained through iterative multiplication, where the obtaining of the exponent conversion code by calculation provided in the embodiment of the present application includes:
after judging the digital code and acquiring the corresponding coefficient code, calculating the j-th intermediate index transform code according to a formula Dac _ code _ j (Dac _ code _ j-1) j-th corresponding coefficient code, wherein Dac _ code _ j is the j-th intermediate index transform code, Dac _ code _ j-1 is the j-1 intermediate exponent transform coding, and the first intermediate exponent transform coding is IComputingThe code of (1) is an integer of which j is more than 1 and not more than N;
until the last coefficient code is calculated according to the calculation rule to obtain the index conversion code.
In an embodiment of the present application, the judgment of the digital code can be made irregularly. Further, the digital judgment provided by the embodiment of the application can be performed through a preset rule, so as to simplify the control sequence, wherein the judgment on all the digital codes is as follows:
and judging all the numbers according to a preset rule.
Optionally, the preset rule provided in this embodiment of the present application is an order from the N-1 th digit to the zeroth digit.
Correspondingly, an embodiment of the present application further provides an index dimming system of a light emitting diode, and reference is made to fig. 3, which is a schematic structural diagram of the index dimming system of the light emitting diode provided in the embodiment of the present application, where the index dimming system of the light emitting diode includes:
the register module 100, where the register module 100 is configured to obtain a dimming control code of Nbit, where the dimming control code includes an N-1 th digit to a zero-th digit that are sequentially arranged, and N is an integer not less than 2; and judging all the numbers, and obtaining the corresponding coefficient of the ith number as [ (I) when the ith number is 1max/Imin)^(1/codemax)]^ (2^ I) and obtaining a corresponding coefficient of 1 when the code is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1;
a calculation module 200, said calculation module 200 being according to formula IDac＝IComputingCalculating to obtain regulating current (corresponding coefficient of N-1 th digit of zero digit of N-1), wherein IDacFor the regulation of current, IComputingIs reference IminCalculating the obtained current value;
and a dimming module 300 dimming the light emitting diode according to the adjustment current.
Understandably, in combination with formula IDac＝IComputingAccording to the technical scheme provided by the embodiment of the application, for the dimming control code of the Nbit, the adjusting current can be obtained only through multiplication calculation of the N times of coefficients, so that the aim of dimming the light-emitting diode is fulfilled, and the dimming method is simpler and can occupy less hardware resources.
In an embodiment of the present application, since the conversion of the dimming control code into the regulated current can be realized by a digital circuit, coefficients and the like involved in the conversion process are all of a binary coding type, that is, the register module and the calculation module are of a digital circuit type. Referring to fig. 4, a schematic structural diagram of another exponential dimming system of a light emitting diode according to an embodiment of the present application is shown, wherein a coefficient of the digital code is a coefficient code pre-stored in a coefficient memory 500, and the register module 100 is configured to obtain a dimming control code of Nbit; and judging all the numbers, and obtaining the corresponding coefficient of the ith number as [ (I) when the ith number is 1max/Imin)^(1/codemax)](2^ I) and obtaining coefficient code corresponding to coefficient 1 when the number is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1;
the calculation module is a multiplier 200, and the multiplier 200 is according to formula Dac _ code ═ IComputingThe code (the corresponding coefficient code of the N-1 th code, the corresponding coefficient code of the zero number) is calculated to obtain the exponential transformation code, wherein Dac _ code is the exponential transformation code, IComputingIs (I)min/IFixing)，IFixingBy conversion from digital to analogueThe minimum current source of the device is controlled to be a fixed value;
the light adjusting module is the digital-to-analog converter DAC, the exponential conversion code is converted into adjusting current through the digital-to-analog converter DAC, and light of the light emitting diode is adjusted according to the adjusting current.
In an embodiment of the present application, when a numerical value of 1 or 0 is determined for a digital code and a coefficient code is multiplied, the multiplication may be performed once after the digital code is determined and the coefficient code is obtained, and a final exponent conversion code is finally obtained through a loop iterative multiplication, that is, the register module includes a first register 101 and a second register 102;
the first register 101 is configured to determine all the numbers after obtaining the dimming control code of Nbit, where after determining one number and obtaining a corresponding coefficient code, the first register controls the corresponding coefficient code to be output to the multiplier 200;
the multiplier 200 calculates a jth intermediate exponent conversion code according to a formula Dac _ code _ j-Dac _ code _ j-1 and transmits the jth coefficient code to the second register 102 for registering, wherein Dac _ code _ j is the jth intermediate exponent conversion code, Dac _ code _ j-1 is the second register 102 for registering the jth-1 intermediate exponent conversion code transmitted to the multiplier, and the first intermediate exponent conversion code is IComputingThe code is obtained by initially judging the coefficient code corresponding to the digital code until the last coefficient code is calculated according to the calculation rule to obtain the index conversion code and transmitting the index conversion code to the second register 102 for registering, wherein j is an integer which is larger than 1 and not larger than N.
Referring to fig. 4, the exponential dimming system of the light emitting diode provided in the embodiment of the present application performs timing control through a counter 400, wherein the counter 400 can control the number of times of calculation of the multiplier 200 and control the second register 102 to transmit the exponential conversion code to the digital-to-analog converter.
In an embodiment of the present application, the judgment of the digital code can be made irregularly. Further, the digital judgment provided by the embodiment of the application can be performed through a preset rule, so as to simplify the control time sequence, wherein the registering module judges all the digital codes as follows:
and judging all the numbers according to a preset rule.
Optionally, the preset rule provided in this embodiment of the present application is an order from the N-1 th digit to the zeroth digit, and this application is not particularly limited.
The embodiment of the application provides an exponential dimming method and system of a light emitting diode, comprising the following steps: obtaining a dimming control code of Nbit, wherein the dimming control code comprises an N-1 th code to a zero number which are sequentially arranged, and N is an integer not less than 2; all the numbers are judged, and when the ith number is 1, the corresponding coefficient of the ith number is obtained to be [ (I)max/Imin)^(1/codemax)]^ (2^ I) and obtaining a corresponding coefficient of 1 when the code is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1; according to formula IDac＝IComputingCalculating to obtain regulating current (corresponding coefficient of N-1 th digit of zero digit of N-1), wherein IDacFor the regulation of current, IComputingIs reference IminCalculating the obtained current value; and dimming the light emitting diode according to the adjusting current.
From the above, it can be seen that formula I is combinedDac＝IComputingAccording to the technical scheme provided by the embodiment of the application, for Nbit dimming control coding, the adjusting current can be obtained only through multiplying of the N times of coefficients, and then the purpose of dimming the light emitting diode is achieved. Specifically, the method comprises the following steps:
compared with the conventional method, the technical scheme provided by the embodiment of the application can be realized by N times of cyclic multiplication through only one multiplier, the circuit area and the cost have obvious advantages, and the consumption of hardware resources is low.
In addition, by using a multiplier with a higher number of bits, exponential mapping with very high precision can be realized. The method is obtained through simulation, under an example dimming formula, an exponential dimming algorithm is provided by the embodiment of the application, an exponential mapping circuit is realized by using 1 multiplier of 15 × 11, and the average error between the current value represented by Dac _ code dimming codes of 15 bits and a theoretical value is only 0.03%;
in addition, compared with the existing iteration method, the technical scheme provided by the embodiment of the application only needs at most N cycles to obtain the result, and the operation speed is greatly improved under the condition of using the multiplier for multiplexing.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. An exponential dimming method of a light emitting diode, comprising:
obtaining a dimming control code of Nbit, wherein the dimming control code comprises an N-1 th code to a zero number which are sequentially arranged, and N is an integer not less than 2;
all the numbers are judged, and when the ith number is 1, the corresponding coefficient of the ith number is obtained to be [ (I)max/Imin)^(1/codemax)]^ (2^ I) and obtaining a corresponding coefficient of 1 when the code is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1;
according to formula IDac＝IComputingCalculating to obtain regulating current (corresponding coefficient of N-1 th digit of zero digit of N-1), wherein IDacFor the regulation of current, IComputingIs reference IminThe calculated current value, the corresponding coefficient of the N-1 th digital code represents the multiplication calculation of the N digital corresponding coefficients from the N-1 st time to the zeroth time;
and dimming the light emitting diode according to the adjusting current.
2. The method for exponentially dimming a light emitting diode according to claim 1, wherein the digital coefficient is a pre-stored coefficient code, and after obtaining the dimming control code of Nbit, the method comprises:
all the numbers are judged, and when the ith number is 1, the corresponding coefficient of the ith number is obtained to be [ (I)max/Imin)^(1/codemax)](2^ I) and obtaining coefficient code corresponding to coefficient 1 when the number is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1;
according to formula Dac _ code ═ IComputingThe code (the code corresponding to the coefficient of the N-1 th code …) and the code corresponding to the coefficient of the zero th code) to obtain the exponential switching code by calculation, wherein Dac _ code is the exponential switching code, IComputingIs (I)min/IFixing)，IFixingThe minimum current source of the digital-to-analog converter is controlled to be a fixed value, and the N-1 corresponding coefficient code … and the zero corresponding coefficient code represent the multiplication calculation of N digital corresponding coefficient codes from the N-1 time to the zero time;
and converting the index conversion code into an adjusting current through the digital-to-analog converter, and dimming the light emitting diode according to the adjusting current.
3. The method for exponentially dimming a light emitting diode according to claim 2, wherein the calculating an exponential transcoding comprises:
after judging the digital code and acquiring the corresponding coefficient code, calculating the j-th intermediate index conversion code according to a formula Dac _ code _ j ═ Dac _ code _ j-1 ×, wherein Dac _ code _ j is the j-th intermediate index conversion code, Dac _ code _ j-1 is the j-1-th intermediate index conversion code, and the first intermediate index conversion code is IComputingThe code of (1) is an integer of which j is more than 1 and not more than N;
until the last coefficient code is calculated according to the calculation rule to obtain the index conversion code.
4. The method for exponentially dimming a light emitting diode according to claim 2, wherein the determining all the numbers comprises:
and judging all the numbers according to a preset rule.
5. The method of claim 4, wherein the predetermined rule is from the N-1 th number to the zeroth number.
6. An exponential dimming system for a light emitting diode, comprising:
the register module is used for acquiring a dimming control code of Nbit, wherein the dimming control code comprises an N-1 th digit to a zero digit which are sequentially arranged, and N is an integer not less than 2; and judging all the numbers, and obtaining the corresponding coefficient of the ith number as [ (I) when the ith number is 1max/Imin)^(1/codemax)]^ (2^ I) and obtaining a corresponding coefficient of 1 when the code is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit,i is an integer of not less than 0 and not more than N-1;
a calculation module according to formula IDac＝IComputingCalculating to obtain regulating current (corresponding coefficient of N-1 code … code and zero code), wherein IDacFor the regulation of current, IComputingIs reference IminThe calculated current value, the corresponding coefficient of the N-1 th digital code represents the multiplication calculation of the N digital corresponding coefficients from the N-1 st time to the zeroth time;
and the dimming module is used for dimming the light emitting diode according to the adjusting current.
7. The led exponential dimming system according to claim 6, wherein the digital coefficients are coefficient codes pre-stored in a coefficient memory, wherein the register module is configured to obtain Nbit dimming control codes; and judging all the numbers, and obtaining the corresponding coefficient of the ith number as [ (I) when the ith number is 1max/Imin)^(1/codemax)](2^ I) and obtaining coefficient code corresponding to coefficient 1 when the number is 0, wherein ImaxIs the maximum drive current of the light emitting diode, IminIs the minimum drive current of the light emitting diodemaxIs the maximum decimal value of the Nbit, i is an integer not less than 0 and not more than N-1;
the calculation module is a multiplier which is according to formula Dac _ code ═ IComputingThe code (the code corresponding to the coefficient of the N-1 th code …) and the code corresponding to the coefficient of the zero th code) to obtain the exponential switching code by calculation, wherein Dac _ code is the exponential switching code, IComputingIs (I)min/IFixing)，IFixingThe minimum current source of the digital-to-analog converter is controlled to be a fixed value, and the N-1 corresponding coefficient code … and the zero corresponding coefficient code represent the multiplication calculation of N digital corresponding coefficient codes from the N-1 time to the zero time;
the light adjusting module is the digital-to-analog converter, converts the index conversion code into adjusting current through the digital-to-analog converter, and adjusts light of the light emitting diode according to the adjusting current.
8. The system of claim 7, wherein the register module comprises a first register and a second register;
the first register is used for judging all the numbers after acquiring the dimming control code of the Nbit, wherein after judging one number and acquiring the corresponding coefficient code, the first register controls the corresponding coefficient code to be output to the multiplier;
the multiplier calculates j-th intermediate index conversion codes according to a formula Dac _ code _ j-Dac _ code _ j-1 j corresponding coefficient codes of j-th number, and transmits the j-th intermediate index conversion codes to the second register for registering, wherein Dac _ code _ j is the j-th intermediate index conversion codes, Dac _ code _ j-1 is the j-1-th intermediate index conversion codes transmitted to the multiplier by the second register for registering, and the first intermediate index conversion codes are I codesComputingThe code is obtained by initially judging the coefficient code corresponding to the digital code until the last coefficient code is calculated according to the calculation rule to obtain the index conversion code and transmitting the index conversion code to the second register to be registered, and j is an integer which is larger than 1 and not larger than N.
9. The led exponential dimming system of claim 8, wherein the led exponential dimming system controls the number of calculations of the multiplier through a counter, and controls the second register to transmit the exponential conversion code to the digital-to-analog converter.
10. The led exponential dimming system of claim 7, wherein the register module determines all of the numbers as:
and judging all the numbers according to a preset rule.
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| CN113905476B (en) * | 2021-10-28 | 2024-02-02 | 上海艾为电子技术股份有限公司 | Index dimming method, mapping circuit, dimming circuit and electronic equipment |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2894944A1 (en) * | 2014-01-14 | 2015-07-15 | Dialog Semiconductor GmbH | Method for improving the accuracy of an exponential current digital-to-analog (IDAC) using a binary-weighted MSB |
| CN204598440U (en) * | 2015-06-02 | 2015-08-26 | 深圳市暗能量电源有限公司 | Novel index light adjusting circuit |
| CN105163418A (en) * | 2015-07-01 | 2015-12-16 | 深圳天珑无线科技有限公司 | Linear light adjustment method and device |
| CN208462113U (en) * | 2018-08-13 | 2019-02-01 | 上海艾为电子技术股份有限公司 | One line light adjusting circuit, chip and system |
| CN109640464A (en) * | 2019-02-27 | 2019-04-16 | 上海客益电子有限公司 | A kind of pwm signal duty ratio control method and corresponding circuit and LED light |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8517562B2 (en) * | 2010-05-04 | 2013-08-27 | Xicato, Inc. | Flexible electrical connection of an LED-based illumination device to a light fixture |
| US8950892B2 (en) * | 2011-03-17 | 2015-02-10 | Cree, Inc. | Methods for combining light emitting devices in a white light emitting apparatus that mimics incandescent dimming characteristics and solid state lighting apparatus for general illumination that mimic incandescent dimming characteristics |
| TWI450637B (en) * | 2011-10-28 | 2014-08-21 | Univ Nat Chi Nan | Dimming device |
| CN106875898B (en) * | 2017-01-17 | 2020-03-06 | 青岛海信电器股份有限公司 | Method and device for adjusting illumination brightness by backlight brightness and liquid crystal display device |
| CN109379804B (en) * | 2018-10-15 | 2023-12-22 | 广东宝莱特医用科技股份有限公司 | Dimming system and dimming method for LED lamp |
| CN110213855B (en) * | 2019-05-23 | 2021-05-04 | 上海艾为电子技术股份有限公司 | Exponential dimming method and system for light emitting diode |
-
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2894944A1 (en) * | 2014-01-14 | 2015-07-15 | Dialog Semiconductor GmbH | Method for improving the accuracy of an exponential current digital-to-analog (IDAC) using a binary-weighted MSB |
| CN204598440U (en) * | 2015-06-02 | 2015-08-26 | 深圳市暗能量电源有限公司 | Novel index light adjusting circuit |
| CN105163418A (en) * | 2015-07-01 | 2015-12-16 | 深圳天珑无线科技有限公司 | Linear light adjustment method and device |
| CN208462113U (en) * | 2018-08-13 | 2019-02-01 | 上海艾为电子技术股份有限公司 | One line light adjusting circuit, chip and system |
| CN109640464A (en) * | 2019-02-27 | 2019-04-16 | 上海客益电子有限公司 | A kind of pwm signal duty ratio control method and corresponding circuit and LED light |
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