Light source driving circuit, method, luminaire and computer readable storage medium

Abstract

The application provides a light source driving circuit and method, and a lamp, the circuit comprising a control chip, a first constant current driving circuit and a second constant current driving circuit connected with a first control end and a second control end of the control chip, and a current detection resistor, the first constant current driving circuit comprising a first constant current chip, the second constant current driving circuit comprising a second constant current chip, a switch tube of the first constant current chip and a switch tube of the second constant current chip being connected with one end of a load light source respectively, the other end of the load light source being connected with the current detection resistor; the first control end and the second control end outputting a first PWM control signal and a second PWM control signal respectively according to a set period, in the set period, the time when the first PWM control signal is high and the time when the second PWM control signal is high are staggered, the first PWM control signal and the second PWM control signal enable the first constant current driving circuit and the second constant current driving circuit to supply power to the load light source in time division, so as to adjust the color temperature and the brightness of the load light source.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a light source driving circuit, method, luminaire, and computer-readable storage medium. Background Technology

[0002] With social progress and evolving needs, people's requirements for lighting fixtures have gone beyond just dimming. Lighting products increasingly utilize CCT (correlated color temperature) dual-color temperature designs to achieve dimming and color adjustment, satisfying the sensory requirements of different groups. Furthermore, the precision and depth of dimming are becoming increasingly demanding, requiring adjustments of one-thousandth or even one-ten-thousandth. To achieve high precision and reliability, constant current chips combined with sensing resistors are often used in the design of light source drive circuits.

[0003] However, the known method of simultaneously dimming and adjusting the color of lamps requires a dual-constant current chip for dual-output design, with each channel using dual-line output, which makes it incompatible with most dual-color lamps or lamp panels on the market, increasing costs. Summary of the Invention

[0004] To address the existing technical problems, this application provides a low-cost, easier-to-implement light source driving circuit and method, as well as a luminaire.

[0005] To achieve the above objectives, the technical solution of this application embodiment is implemented as follows:

[0006] In a first aspect, embodiments of this application provide a light source driving circuit, including a control chip, a first constant current driving circuit connected to a first control terminal of the control chip, a second constant current driving circuit connected to a second control terminal of the control chip, and a current sensing resistor connected to the first constant current driving circuit and the second constant current driving circuit. The first constant current driving circuit includes a first constant current chip, and the second constant current driving circuit includes a second constant current chip. The switching transistors of the first constant current chip and the second constant current chip are respectively connected to one end of a load light source, and the other end of the load light source is connected to the current sensing resistor.

[0007] The first control terminal and the second control terminal output a first PWM control signal and a second PWM control signal respectively according to a set period. Within the set period, the time when the first PWM control signal is at a high level and the time when the second PWM control signal is at a high level are staggered. The first PWM control signal and the second PWM control signal enable the first constant current drive circuit and the second constant current drive circuit to supply power to the load light source in a time-division manner, so as to adjust the color temperature and brightness of the load light source.

[0008] Secondly, embodiments of this application provide a light source driving method, applied to a light source driving circuit, comprising:

[0009] During the first time period of the set period, a high-level control signal is output to the corresponding first constant current chip, and a low-level control signal is output to the corresponding second constant current chip or the output control signal is stopped during the first time period of the set period.

[0010] During the first time period, the first constant current chip enters the working state by connecting with the load light source through the current detection resistor, and the first constant current chip drives the load light source to emit light.

[0011] During the second time period of the set cycle, a high-level control signal is output to the corresponding connected second constant current chip, and a low-level control signal or a stop output control signal is output to the corresponding connected first constant current chip during the second time period of the set cycle; the first time period and the second time period are staggered.

[0012] During the second time period, the second constant current chip enters the working state by connecting to the load light source through the current detection resistor, and the second constant current chip drives the load light source to emit light.

[0013] Thirdly, embodiments of this application provide a lamp, including a light source driving circuit as described in any embodiment of this application and a load light source connected to the light source driving circuit. One end of the load light source is connected to the switching transistor of the first constant current chip and the switching transistor of the second constant current chip, and the other end is connected to the current sensing resistor.

[0014] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the light source driving method described in the first aspect above.

[0015] The light source driving circuit and method, lamp, and computer-readable storage medium provided in the above embodiments of this application are configured to connect the switching transistors of the first constant current chip and the second constant current chip to one end of the load light source, and the other end of the load light source to the current sensing resistor. The first control terminal and the second control terminal of the control chip output a first PWM control signal and a second PWM control signal respectively according to a set period. Within the set period, the time when the first PWM control signal is high level and the time when the second PWM control signal is high level are staggered. The first PWM control signal and the second PWM control signal enable the first constant current driving circuit and the second constant current driving circuit to supply power to the load light source in a time-division manner, so as to adjust the color temperature and brightness of the load light source. By using two PWM control signals to enable two constant current chips in a time-division manner, and the two constant current chips time-division multiplexing the same current sensing resistor to supply power to the load light source, the adjustment of the color temperature and brightness of the load light source is realized. Therefore, it is not necessary to change the wiring method between each constant current chip and the load light source, which has better compatibility, simpler circuit structure, and is easier to implement. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a light source driving circuit in one embodiment of this application;

[0017] Figure 2 This is a schematic diagram of a light source driving circuit in another embodiment of this application;

[0018] Figure 3 This is a schematic diagram of the first constant current driving circuit and the second constant current driving circuit in the embodiments of this application;

[0019] Figure 4 This is a schematic diagram of the control chip in an embodiment of this application;

[0020] Figure 5 This is a schematic diagram of the step-down circuit in an embodiment of this application;

[0021] Figure 6 This is a schematic diagram of the first PWM control signal and the second PWM control signal in an embodiment of this application;

[0022] Figure 7 This is a schematic diagram of the first PWM control signal and the second PWM control signal in another embodiment of this application;

[0023] Figure 8 This is a schematic diagram of the first PWM control signal and the second PWM control signal in another embodiment of this application;

[0024] Figure 9 This is a flowchart of a light source driving method in one embodiment of this application;

[0025] Figure 10 This is a flowchart of a light source driving method in another embodiment of this application;

[0026] Figure 11 It is a computer-readable storage medium according to an embodiment of this application. Detailed Implementation

[0027] The technical solution of this application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the ways in which this application may be implemented. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] In the description of this application, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0030] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0031] The inventors of this application have studied the design of a dual-chip dual-output control circuit for a load light source and summarized the following solutions:

[0032] First, when the load light source is connected between the switching transistor and the sensing resistor of the constant current chip, and the dual-chip dual-output control is adopted, the load light source is connected between the switching transistor and the high-side sensing resistor of the constant current chip, and between the switching transistor and the low-side sensing resistor of the constant current chip. Then, the two constant current chips need four output lines to ensure that the performance is not affected. However, the four-wire design is not compatible with most lamps or lamp boards with dual color temperature and brightness adjustment on the market. Adding an output line also increases the cost.

[0033] Secondly, to solve the incompatibility problem caused by the four-output-line design, one approach is to move the load light source in the loop between the sensing resistor and the electrode ground to achieve a common-cathode three-wire design; another approach is to move the load light source in the loop between the power supply and the sensing resistor to achieve a common-anode three-wire design. However, this method connects the load light source in series with the front end of the constant current chip, which will cause the voltage at the switching transistor terminal and the sensing resistor terminal to be too low when the constant current chip's switching transistor is turned on. This will cause the constant current chip to malfunction or the performance parameters of the entire circuit to deteriorate significantly.

[0034] The above solution has the following drawbacks: A. Existing constant current chips that can directly use common anode or common cathode can only achieve a dimming depth of 1%, which cannot meet higher design requirements. Using the aforementioned high-end or low-end sensing resistors requires direct four-wire output, increasing costs and making them incompatible with the interfaces of warm and cool color temperature lamps on the market. B. When an external DIP switch is added to adjust the output current so that users can adjust the output current to adapt to different lamps, both circuits need an identical DIP switch to adjust the current, and they need to be consistent. Two DIP switches take up a lot of space, are inconvenient for users to operate, and also increase product costs. C. Using constant current chips with high-end or low-end sensing resistors for three-wire circuit conversion design can lead to problems with startup or operation. In dimming mode, this causes a discrepancy between the minimum duty cycle for normal dimming and the minimum duty cycle for startup after power restoration. For example, if the power is suddenly cut off after dimming to 10%, the controller will not be able to start the constant current chip after power is restored, often requiring the duty cycle to be increased to light up, which has a significant impact on product performance. D. Using a constant current chip with either a high-side or low-side sensing resistor in a three-wire circuit conversion design, the constant current chip is connected in series after the load light source. Since the chip itself has a minimum operating voltage, the front-end voltage needs to be designed higher, potentially leading to insufficient margin. Furthermore, the voltage of the load light source itself and the voltage difference increase, reducing efficiency. E. Using a constant current chip with either a high-side or low-side sensing resistor in a three-wire circuit conversion design, the chip's own power consumption after the load light source will cause the load light source to light up. When the PWM is low, it cannot be completely extinguished, requiring a power supply / discharge resistor connected in parallel across the load light source. This resistor, with a fixed input voltage and a wide voltage load, will cause inconsistent extinguishing points for different voltage loads, preventing simultaneous extinguishing of the minimum duty cycle and making it impossible to unify the minimum extinguishing point.

[0035] To address the shortcomings of the aforementioned solutions, the inventors of this application have developed a new light source driving circuit that utilizes two PWM control signals containing dimming signals and color temperature ratio information to enable two constant current chips in a time-division manner. This allows the two constant current chips to share the same detection resistor. The timing employs a time-division complementary and staggered enabling mechanism using the two PWM control signals to ensure that only one constant current chip is in use at any given time. By enabling the two constant current chips in a time-division manner using the two PWM control signals, the color temperature and brightness of the load light source 10 can be adjusted. This eliminates the need to change the wiring method between each constant current chip and the load light source 10, resulting in a new light source driving circuit with better compatibility, a simpler circuit structure, and easier implementation. Please refer to [link to relevant documentation]. Figure 1 This application provides a light source driving circuit in one embodiment, including a control chip U2, a first constant current driving circuit connected to a first control terminal of the control chip U2, a second constant current driving circuit connected to a second control terminal of the control chip U2, and a current sensing resistor R24 ​​connected to the first and second constant current driving circuits. The first constant current driving circuit includes a first constant current chip U3, and the second constant current driving circuit includes a second constant current chip U4. The switching transistors of the first and second constant current chips U3 and U4 are respectively connected to one end of a load light source 10, and the other end of the load light source 10 is connected to the current sensing resistor R24. The first and second control terminals output a first PWM control signal and a second PWM control signal according to a set period. Within the set period, the time when the first PWM control signal is high and the time when the second PWM control signal is high are staggered. The first and second PWM control signals enable the first and second constant current driving circuits to supply power to the load light source 10 in a time-division manner, so as to adjust the color temperature and brightness of the load light source 10.

[0036] In the above embodiment, the switching transistors of the first constant current chip U3 and the second constant current chip U4 are respectively connected to one end of the load light source 10, and the other end of the load light source 10 is connected to the current sensing resistor R24. The first control terminal and the second control terminal output a first PWM control signal and a second PWM control signal respectively according to a set period. Within the set period, the time when the first PWM control signal is high and the time when the second PWM control signal is high are staggered. The first PWM control signal and the second PWM control signal enable the first constant current drive circuit and the second constant current drive circuit to supply power to the load light source 10 in a time-division manner to adjust the color temperature and brightness of the load light source 10. By using two PWM control signals to enable two constant current chips in a time-division manner, and the two constant current signals to use the same current sensing resistor R24 ​​to supply power to the load light source 10 in a time-division manner, the adjustment of the color temperature and brightness of the load light source 10 is realized. Therefore, it is not necessary to change the wiring method between each constant current chip and the load light source 10, which has better compatibility, simpler circuit structure and is easier to implement.

[0037] Please see Figure 1 One end of the load light source 10 is connected to the switching transistors of the first constant current chip U3 and the second constant current chip U4, and the other end is connected to the current sensing resistor R24. This can mean that the current sensing resistor R24 ​​is connected between the DC power supply 12 and the load light source 10, and the current sensing resistor R24 ​​and the load light source 10 are connected with a common anode; or, please refer to [link to relevant documentation]. Figure 2 One end of the load light source 10 is connected to the switching transistors of the first constant current chip U3 and the second constant current chip U4, and the other end is connected to the current sensing resistor R24. Alternatively, the current sensing resistor R24 ​​can be connected between the load light source 10 and the electrode ground, and the current sensing resistor R24 ​​is connected to the load light source 10 with a common cathode. The control chip U2 outputs a first PWM control signal and a second PWM control signal to the first constant current chip U3 and the second constant current chip U4, respectively.

[0038] Please see Figure 3The first constant current chip U3 and the second constant current chip U4 are identical. Each constant current chip includes a current detection terminal CS, a power supply voltage terminal VIN, an internal switching transistor terminal SW, and a brightness control terminal DIM. The internal switching transistor terminal SW is the drain of the internal field-effect transistor in the first constant current chip U3 and the second constant current chip U4. Since the first constant current chip U3 and the second constant current chip U4 have internal field-effect transistors, connecting one end of the load light source 10 to the switching transistors of the first constant current chip U3 and the second constant current chip U4 means connecting one end of the load light source 10 to the internal switching transistor terminal SW of the first constant current chip U3 and the second constant current chip U4. The brightness control terminal DIM of the first constant current chip U3 and the second constant current chip U4 is connected to the first control terminal and the second control terminal of the control chip U2, respectively. The current detection resistor R24 ​​is connected between the current detection terminal CS and the power supply voltage terminal VIN of the first constant current chip U3. The two ends of the load light source 10 are respectively connected to the current detection terminal CS and the built-in switching terminal SW of the first constant current chip U3, and respectively connected to the current detection terminal CS and the built-in switching terminal SW of the second constant current chip U4. Based on the first PWM control signal and the second PWM control signal received from the control chip U2, the first constant current chip U3 operates while the second constant current chip U4 stops operating; conversely, the second constant current chip U4 operates while the first constant current chip U3 stops operating. The first constant current chip U3 and the second constant current chip U4 time-division multiplex the current detection resistor R24, controlling the switching transistor to turn on or off by detecting whether the voltage across the current detection resistor R24 ​​reaches the rated threshold.

[0039] The value of the current sensing resistor R24 ​​can be determined based on the magnitude of the load current flowing through the load light source 10. When the voltage across the load light source 10 tends to stabilize, the inductor current can be approximated as linearly changing. The magnitude of the load current flowing through the load light source 10 is equal to the current flowing through the current sensing resistor R24. Therefore, the value of the current sensing resistor R24 ​​is linearly proportional to the magnitude of the load current, as shown in the following formula:

[0040] Iled = K / Rcs (K is a constant)

[0041] Where Iled represents the load current flowing through the load light source 10, and Rcs represents the resistance value of the current sensing resistor R24.

[0042] Please see Figure 4The diagram below illustrates a control chip U2, an optional specific example provided in this application. The control chip U2 is a programmable logic device, including a power supply terminal, a first PWM signal output terminal, and a second PWM signal output terminal. The power supply terminal is connected to the output terminal of the step-down circuit 15. The first and second PWM signal output terminals serve as the first and second control terminals of the control chip U2, respectively connected to the switching transistors of the first constant current chip U3 and the second constant current chip U4.

[0043] Please see Figure 5 The diagram below illustrates a step-down circuit 15, an optional specific example provided in this application. The step-down circuit 15 supplies power to the control chip U2, the first constant current chip U3, and the second constant current chip U4. It includes a first output terminal VIN for connecting to the power supply voltage terminals VIN of the first and second constant current chips U3 and U4, and a second output terminal SW for connecting to the power supply terminal of the control chip U2. The step-down circuit 15 can be designed using a known chip model, such as the MP9486 step-down chip U1.

[0044] In some embodiments, during the time-division multiplexing of the current sensing resistor R24 ​​by the first constant current chip U3 and the second constant current chip U4 according to the first PWM control signal and the second PWM control signal received from the control chip U2, the operation of the first constant current chip U3 and the second constant current chip U4 remains consistent with the high-level state of the corresponding first PWM control signal and the second PWM control signal, respectively. Please refer to... Figure 6 The first PWM control signal and the second PWM control signal have equal periods. Within a set period, the sum of the first percentage and the second percentage of the first PWM control signal is 1. The time-division ratio of the first PWM control signal and the second PWM control signal is the ratio of the first percentage to the second percentage. Within a set period, when the first PWM control signal is high, the second PWM control signal is correspondingly low; when the first PWM control signal is low, the second PWM control signal is correspondingly high, ensuring that at any given time, only one constant current chip, in conjunction with the current sensing resistor R24, provides constant current control to the load light source.

[0045] Optionally, during the time-sharing process of the first constant current chip U3 and the second constant current chip U4 enabling the first constant current drive circuit and the second constant current drive circuit to supply power to the load light source 10, the high level of the first PWM control signal and the high level of the second PWM control signal can also be time-divided and staggered. Please refer to [link / reference]. Figure 7Within the set period, the sum of the first percentage of the first PWM control signal and the second percentage of the second PWM control signal is less than 1. The time-division percentage of the first PWM control signal and the second PWM control signal is the ratio of the first percentage to the second percentage. That is, within a set period, when the first PWM control signal is high, the second PWM control signal can be low or empty accordingly; when the first PWM control signal is high, the second PWM control signal can be low or empty accordingly. This ensures that at any given time, only one constant current chip, combined with the current sensing resistor R24, provides constant current control to the load light source.

[0046] The first PWM control signal and the second PWM control signal simultaneously include dimming signals and color temperature ratio information. The first constant current chip U3 and the second constant current chip U4 control warm light and cool light respectively, thereby correspondingly controlling the operation of the first constant current chip U3 and the second constant current chip U4 as warm light control pulse signals and cool light control pulse signals, respectively. The total brightness of the load light source 10 includes warm and cool light information. Taking the first constant current chip U3 controlling warm light and the second constant current chip U4 controlling cool light as an example, in the light emitted by the load light source 10, the proportion of warm light is the product of the total brightness and the first proportion of the first PWM control signal, and the proportion of cool light is the product of the total brightness and the second proportion of the second PWM control signal. Thus, when controlling the load light source 10, the total brightness can be allocated according to the color temperature ratio. While keeping the set period constant, changing the time-division ratio of the first PWM control signal and the second PWM control signal can adjust the color temperature of the load light source 10 accordingly; and changing the set period while keeping the time-division ratio constant can adjust the total brightness of the load light source 10 accordingly.

[0047] Taking Dw as the duty cycle of warm color temperature and Dc as the duty cycle of cool color temperature as an example, when the total brightness is D (0≤D≤1), the proportion of cool light is D1=D*Dc, the first PWM control signal PWM1=D1=D*Dc, the proportion of warm light is D2=D*Dw, and the second PWM control signal PWM2=D2=D*Dw=D*(1-Dc). When the control signal adjusts the brightness of the load light source 10 through two constant current chips, the size of the set period D can be changed, but the time ratio of PWM1 and PWM2 within the set period is still distributed according to the ratio of Dc:Dw, so that the brightness changes while the color temperature remains unchanged; when the control signal adjusts the color temperature of the load light source 10 through two constant current chips, only the ratio of Dc:Dw can be changed, but the size of the set period remains unchanged, so that the brightness remains unchanged while the color temperature changes. It can be understood that when it is necessary to adjust the brightness and color temperature of the load light source 10 at the same time, it can be achieved by changing the set period D and the size of Dc:Dw simultaneously.

[0048] In another alternative embodiment, please refer to Figure 8 The first and second PWM control signals can also correspond to color temperature adjustment and brightness adjustment, respectively. For example, the control chip U2 provides a fixed high-frequency PWM signal, and then uses a relatively low frequency to distribute the high-frequency PWM signal to the first and second control terminals to output the first and second PWM control signals. The first PWM control signal is a high-frequency PWM signal, and the second PWM control signal is a low-frequency PWM signal. The first constant current chip U3 controls the brightness, and the second constant current chip controls the color temperature. When it is necessary to adjust the brightness of the load light source 10, the proportion of the high-frequency PWM signal can be directly adjusted. When it is necessary to adjust the color temperature of the load light source 10, the proportion of the low-frequency signal can be adjusted, so that the output time of the high-frequency PWM signal at the first and second control terminals varies according to the color temperature configuration.

[0049] In another aspect of the embodiments of this application, please refer to Figure 9 Furthermore, a light source driving method is provided, which can be applied to the light source driving circuit provided in any embodiment of this application. The method includes the following steps:

[0050] S11, the control chip outputs a high-level control signal to the corresponding first constant current chip during the first time period of the set period, and outputs a low-level control signal to the corresponding second constant current chip or stops outputting the control signal during the first time period of the set period.

[0051] S12, during the first time period, the first constant current chip enters the working state by connecting with the load light source through the current detection resistor, and the first constant current chip drives the load light source to emit light.

[0052] S13, the control chip outputs a high-level control signal to the corresponding connected second constant current chip during the second time period of the set period, and outputs a low-level control signal to the corresponding connected first constant current chip or stops outputting a control signal during the second time period of the set period; the first time period and the second time period are staggered.

[0053] S14, during the second time period, the second constant current chip enters the working state by connecting to the load light source through the current detection resistor, and the second constant current chip drives the load light source to emit light.

[0054] The quantity in the first time period within a set period can be one or more, and the quantity in the second time period within a set period can also be one or more. The sum of the first percentage of the first time period within the first set period and the second percentage of the second time period within the set period is equal to 1, or the sum of the first percentage and the second percentage is less than 1. Figure 6 For example, let the period be D, the first time period be Dw, the second time period be Dc, and the sum of the first and second proportions equal to 1; Figure 7 For example, let the period be D, the first time period be Dw, the second time period be Dc, and the sum of the first and second proportions be less than 1; Figure 8 For example, the period is set as follows: the first period includes multiple separate first time intervals T1, and the second period includes multiple separate second time intervals T2.

[0055] When the control chip outputs a high-level control signal to the first constant current chip, it outputs a low-level control signal to the corresponding connected second constant current chip or stops outputting the control signal; and when it outputs a high-level control signal to the second constant current chip, it outputs a low-level control signal to the corresponding connected first constant current chip or stops outputting the control signal. This allows the first and second constant current chips to share the same current sensing resistor to supply power to the load light source in a time-division multiplexing manner, thereby adjusting the color temperature and brightness of the load light source. This eliminates the need to change the wiring method between each constant current chip and the load light source, resulting in better compatibility, a simpler circuit structure, and easier implementation.

[0056] Optional, please refer to Figure 10 The light source driving method further includes:

[0057] S15, when receiving a brightness adjustment command for the load light source, the duration of the set period is adjusted to maintain the ratio of the first time period to the second time period within the adjusted set period unchanged;

[0058] S16, when a color temperature adjustment command is received for the load light source, the duration of the set period is kept unchanged, and the ratio of the first time period and the second time period within the set period is adjusted.

[0059] The total brightness of the load light source includes both warm and cool light information. A first constant current chip and a second constant current chip control the cool and warm light of the load light source, respectively. Taking the first constant current chip controlling the warm light and the second constant current chip controlling the cool light as an example, the proportion of warm light emitted by the load light source is the product of the total brightness and the first proportion of the first duration within the set period, while the proportion of cool light is the product of the total brightness and the second proportion of the second duration within the set period. Thus, when controlling the load light source, the total brightness can be allocated according to the ratio of warm to cool light. While keeping the set period constant, changing the ratio of the first time period to the second time period can adjust the color temperature of the load light source accordingly. Conversely, changing the set period while keeping the ratio of the first time period to the second time period constant can adjust the total brightness of the load light source. It should be noted that brightness and color temperature adjustments of the load light source can be performed simultaneously, or only brightness or only color temperature can be adjusted.

[0060] This application also provides a lighting fixture, which includes the light source driving circuit described in the foregoing embodiments and a load light source connected to the light source driving circuit. One end of the load light source is connected to the switching transistors of the first constant current chip U3 and the second constant current chip U4, and the other end is connected to the current sensing resistor R24. The load light source can be an LED lamp or other light source, and the lamp can accordingly be an LED lamp.

[0061] The light source driving circuit and method provided in this application, and the lamp having the light source driving circuit, have at least the following characteristics:

[0062] First, a dual-channel constant current chip is used to design a three-wire common anode or common cathode dual-color temperature light source driving circuit. The first constant current driving circuit and the second constant current driving circuit are enabled in a time-division manner by the first PWM control signal and the second PWM control signal to supply power to the load light source 10, so as to adjust the color temperature and brightness of the load light source 10, maintain good driving performance and original wiring relationship, have good compatibility, lower cost and are easier to implement.

[0063] Secondly, the first constant current chip U3 and the second constant current chip U4 share the current detection resistor R24 ​​in a time-sharing manner. The load light source 10 and the constant current chip are essentially connected in parallel across the output voltage terminals. The input voltage can be closer to the load voltage of the load light source, which is more effective than the known method of connecting the load light source in series in the load circuit of the constant current chip.

[0064] Third, the first constant current chip U3 and the second constant current chip U4 share the current detection resistor R24 ​​in a time-sharing manner, which maintains the original circuit of the constant current chip. The constant current chip is controlled only by the enable pin (DIM) of the constant current chip, thus avoiding the problem of inconsistent start points of the constant current chips or failure to power on.

[0065] Fourth, it can save one current sensing resistor R24, which is beneficial for saving space and cost. It is especially suitable for occasions where the sensing resistor is adjusted by DIP switch to control the maximum output current. Moreover, the dual drive current formed by the first constant current chip U3 and the second constant current chip U4 is consistent, which makes it more convenient for users to operate.

[0066] This application also provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the various processes of the above-described rule processing method embodiments and achieves the same technical effects. To avoid repetition, it will not be described again here. The computer-readable storage medium may include a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0067] Figure 11 This is a structural block diagram of a computer-readable storage medium 800 provided in an embodiment of this application. The computer-readable storage medium 800 stores program code, which can be called by a processor to execute the methods provided in the above embodiments. Figure 9 , Figure 10 ,and Figure 11 Any light source driving method. The computer-readable storage medium 800 may be an electronic memory such as flash memory, EEPROM (Electrically Erasable Programmable Read-Only Memory), EPROM, hard disk, or ROM. Optionally, the computer-readable storage medium 800 includes a non-transitory computer-readable storage medium. The computer-readable storage medium 800 has storage space for program code 810 that performs any of the method steps described above. This program code can be read from or written to one or more computer program products. The program code 810 may, for example, be compressed in a suitable form.

[0068] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A light source driving circuit, characterized by comprising: The control chip, a first constant current driving circuit connected with a first control end of the control chip, a second constant current driving circuit connected with a second control end of the control chip, and a current detection resistor connected with the first constant current driving circuit and the second constant current driving circuit, the first constant current driving circuit comprises a first constant current chip, the second constant current driving circuit comprises a second constant current chip, a switch tube of the first constant current chip and a switch tube of the second constant current chip are respectively connected with one end of a load light source, and the other end of the load light source is connected with the current detection resistor. The first control end and the second control end respectively output a first PWM control signal and a second PWM control signal according to a set period, and the time when the first PWM control signal is high and the time when the second PWM control signal is high are staggered in the set period, and the first PWM control signal and the second PWM control signal enable the first constant current driving circuit and the second constant current driving circuit to supply power to the load light source in time sharing mode to adjust the color temperature and brightness of the load light source. The control chip changes the size of the set period and / or the size of the time sharing ratio of the first PWM control signal and the second PWM control signal in the set period to realize separate adjustment or simultaneous adjustment of the color temperature and brightness of the load light source.

2. The light source driving circuit according to claim 1, wherein In the set period, the sum of the first ratio of the first PWM control signal and the second ratio of the second PWM control signal is 1, and the time sharing ratio of the first PWM control signal and the second PWM control signal is the ratio of the first ratio to the second ratio.

3. The light source driving circuit according to claim 1, wherein In the set period, the sum of the first ratio of the first PWM control signal and the second ratio of the second PWM control signal is less than 1, and the time sharing ratio of the first PWM control signal and the second PWM control signal is the ratio of the first ratio to the second ratio.

4. The light source driving circuit as described in claim 2 or 3, characterized in that, The first constant current chip controls warm light, and the second constant current chip controls cold light.

5. The light source driving circuit according to claim 4, wherein In the light emitted by the load light source, the warm light ratio is the product of the total brightness and the first ratio, and the cold light ratio is the product of the total brightness and the second ratio.

6. The light source driving circuit according to claim 2 or 3, wherein The control chip changes the size of the set period and / or the size of the time sharing ratio of the first PWM control signal and the second PWM control signal to realize adjustment of the color temperature of the load light source under the condition that the total brightness of the load light source is unchanged.

7. The light source driving circuit according to claim 2 or 3, wherein The control chip changes the size of the set period and / or the size of the time sharing ratio of the first PWM control signal and the second PWM control signal to realize adjustment of the color temperature of the load light source under the condition that the total brightness of the load light source is unchanged.

8. The light source driving circuit according to claim 2 or 3, wherein The first PWM control signal is a high-frequency PWM signal, the second PWM control signal is a low-frequency PWM signal, the first constant current chip controls brightness, and the second constant current chip controls color temperature.

9. The light source driving circuit according to claim 1, wherein A step-down circuit connected with the control chip and a direct current power supply connected with the step-down circuit are further included.

10. A light source driving method applied to a light source driving circuit, characterized by, The control chip, a first constant current driving circuit connected with a first control end of the control chip, a second constant current driving circuit connected with a second control end of the control chip, and a current detection resistor connected with the first constant current driving circuit and the second constant current driving circuit, the first constant current driving circuit comprises a first constant current chip, the second constant current driving circuit comprises a second constant current chip, a switch tube of the first constant current chip and a switch tube of the second constant current chip are respectively connected with one end of a load light source, and the other end of the load light source is connected with the current detection resistor. outputting a high-level control signal to a corresponding connected first constant current chip in a first period of a set cycle, outputting a low-level control signal or stopping outputting a control signal to a corresponding connected second constant current chip in the first period of the set cycle; in the first period, the first constant current chip is turned on to enter a working state through a current detection resistor and a load light source, and the first constant current chip drives the load light source to emit light; outputting a high-level control signal to a corresponding connected second constant current chip in a second period of the set cycle, outputting a low-level control signal or stopping outputting a control signal to a corresponding connected first constant current chip in the second period of the set cycle; the first period and the second period are staggered with each other; in the second period, the second constant current chip is turned on to enter a working state through the current detection resistor and the load light source, and the second constant current chip drives the load light source to emit light; wherein by changing the size of the set cycle and / or the size of the time-sharing ratio in the set cycle, the color temperature and the brightness of the load light source are adjusted individually or simultaneously; the time-sharing ratio refers to the ratio of a first ratio of the control signal output to the first constant current chip to a second ratio of the control signal output to the second constant current chip.

11. The light source driving method according to claim 10, wherein Further comprising: when a brightness adjustment instruction for the load light source is received, adjusting the length of the set cycle, and maintaining the ratio of the first period to the second period in the adjusted set cycle unchanged; and / or when a color temperature adjustment instruction for the load light source is received, maintaining the length of the set cycle unchanged, and adjusting the ratio of the first period to the second period in the set cycle.

12. A luminaire characterized by, The light source driving circuit according to any one of claims 1 to 9 and a load light source connected with the light source driving circuit, one end of the load light source is connected with a switch tube of the first constant current chip and a switch tube of the second constant current chip, and the other end is connected with the current detection resistor.

13. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the light source driving method according to any one of claims 10 to 11.

Images