Light emitting element driving circuit and driving chip

Abstract

The present invention discloses a light emitting element driving circuit and a driving chip, the light emitting element driving circuit includes a driving power supply stage and an impedance adjustment module arranged in a branch circuit where a light emitting element is located, and an impedance adjustment branch circuit connected in parallel to the driving power supply stage, the adjustment output terminal of the impedance adjustment branch circuit is coupled to the impedance adjustment module, and the impedance adjustment branch circuit is configured to adjust the impedance of the impedance adjustment module according to the two-sided voltage of the driving power supply stage. The light emitting element driving circuit provided by the present invention can improve the voltage drop of the driving power supply stage, balance the power consumption and heat generation of the driving circuit itself, and improve the driving ability of the circuit.

Description

[Technical Field]

[0001] (Related Applications) This application claims priority to a Chinese patent application filed on July 29, 2022, application number 202210418984.X, entitled "Light-emitting element driving circuit, device and power-using device," and a Chinese patent application filed on November 17, 2022, application number 202223090989.9, entitled "Light-emitting element low-side driving circuit, chip and power-using device," the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to the technical field of electronic circuits, and in particular to a light emitting element driving circuit and driving chip. [Background technology]

[0003] The prior art provides a light-emitting element driving circuit as shown in FIG. 1. This circuit includes a DC power supply 11, a driver chip 12, and a light-emitting element 13 connected in series. The electric energy generated by the DC power supply 11 is converted into an appropriate constant current by the driver chip 12 and then transmitted to one or more light-emitting elements 13 connected in series at the rear end to drive the light-emitting elements. To ensure constant current output, the voltage difference between the input and output terminals of the driver chip 12 must be greater than a certain value. However, because the forward voltage drop of the light-emitting element varies or deviates, a sufficient voltage margin must be ensured when setting the output voltage of the power supply 11. However, this voltage margin and the heat generated by the self-powered consumption of the constant current output from the driver chip 12 are limited by the heat dissipation capability of the chip package. Therefore, the light-emitting element driving circuit provided in the prior art has problems such as high power consumption, high heat generation, and limited driving capability. Summary of the Invention

[0004] One of the objects of the present invention is to provide a light-emitting element driving circuit that can solve the technical problems of the prior art, such as the high power consumption, high heat generation, and limited output current capacity of the light-emitting element driving circuit itself.

[0005] One of the objects of the present invention is to provide a light emitting element driving chip.

[0006] To achieve one of the above objects, one embodiment of the present invention provides a light emitting element driving circuit, the circuit including: a driving power supply stage and an impedance adjustment module disposed in a branch circuit in which a light emitting element is located; and an impedance adjustment branch circuit connected in parallel with the driving power supply stage, the adjustment output terminal of the impedance adjustment branch circuit being coupled to the impedance adjustment module, and the impedance adjustment branch circuit being configured to adjust the impedance of the impedance adjustment module according to the voltage across the driving power supply stage.

[0007] As a further improvement of one embodiment of the present invention, the impedance adjustment sub-circuit is configured to adjust the impedance of the impedance adjustment module to increase when the voltage drop of the driving power supply stage is greater than a predetermined compensation voltage value, and / or the impedance adjustment sub-circuit is configured to adjust the impedance of the impedance adjustment module to decrease when the voltage drop of the driving power supply stage is less than a predetermined compensation voltage value.

[0008] As a further improvement to one embodiment of the present invention, the voltage drop of the driving power supply stage is the difference between the driving input terminal voltage value of the driving power supply stage and its driving output terminal voltage value, and the impedance adjustment subcircuit is configured to adjust the impedance of the impedance adjustment module to continuously increase until the difference between the driving input terminal voltage value and the driving output terminal voltage value converges to the predetermined compensation voltage value when the voltage drop of the driving power supply stage is greater than a predetermined compensation voltage value; and the impedance adjustment subcircuit is configured to adjust the impedance of the impedance adjustment module to continuously decrease until the difference between the driving input terminal voltage value and the driving output terminal voltage value converges to the predetermined compensation voltage value when the voltage drop of the driving power supply stage is smaller than the predetermined compensation voltage value.

[0009] In a further refinement of an embodiment of the present invention, the impedance adjustment module comprises a shunt module and a variable resistance module connected in parallel with each other.

[0010] As a further improvement of an embodiment of the present invention, the adjustment output terminal is coupled to the adjustment control terminal of the variable resistance module, and the impedance adjustment sub-circuit is configured to adjust the impedance of the variable resistance module according to the voltages on both sides of the driving power supply stage.

[0011] As a further improvement of an embodiment of the present invention, the impedance adjustment sub-circuit is configured to adjust the impedance of the variable resistance module to increase when the voltage drop of the driving power supply stage is greater than a predetermined compensation voltage value, and / or the impedance adjustment sub-circuit is configured to adjust the impedance of the variable resistance module to decrease when the voltage drop of the driving power supply stage is less than a predetermined compensation voltage value.

[0012] As a further improvement of an embodiment of the present invention, the impedance adjustment branch circuit includes a compensation circuit and an error amplifier circuit, an output terminal of the error amplifier circuit is coupled to the impedance adjustment module, and a first input terminal of the error amplifier circuit is coupled to the impedance adjustment module. teeth The compensation circuit is connected between the driving power supply stage and the light emitting device, and the second input terminal of the error amplifier circuit is connected to the other end of the driving power supply stage that is not connected to the light emitting device, and the compensation circuit is Voltage drop is configured to compensate for

[0013] As a further improvement of an embodiment of the present invention, the light emitting element driving circuit further includes a sampling circuit, and the error amplifier circuit is coupled between the driving power supply stage and the light emitting element via the compensation circuit and the sampling circuit, and the sampling circuit is configured to collect voltage extreme values ​​of nodes between the driving power supply stage and the light emitting element, and the compensation circuit is The predetermined compensation voltage valueThe voltage extremes are compensated for in response to a compensation voltage.

[0014] As a further improvement of one embodiment of the present invention, when the light-emitting element is coupled to the drive input terminal of the drive power supply stage, the sampling circuit is configured to collect a sampling voltage with a minimum voltage value at the drive input terminal, and the compensation circuit is configured to negatively compensate the sampling voltage in accordance with the compensation voltage; and when the light-emitting element is coupled to the drive output terminal of the drive power supply stage, the sampling circuit is configured to collect a sampling voltage with a maximum voltage value at the drive output terminal, and the compensation circuit is configured to positively compensate the sampling voltage in accordance with the compensation voltage.

[0015] As a further improvement to one embodiment of the present invention, the impedance adjustment module is connected in series between a power supply and the driving input terminal of the driving power supply stage, the light emitting device is connected in series between the driving output terminal of the driving power supply stage and ground, the compensation circuit includes a first N-type transistor, a first P-type transistor and a compensation resistor, the gate of the first N-type transistor is coupled to the sampling circuit, the drain is coupled to the power supply, and the source is coupled to the gate of the first P-type transistor, the drain of the first P-type transistor is grounded and the source is coupled to the error amplifier circuit via the compensation resistor.

[0016] As a further improvement to one embodiment of the present invention, the impedance adjustment module is connected in series between the driving output terminal of the driving power supply stage and ground, the light emitting device is connected in series between a power supply and the driving input terminal of the driving power supply stage, and the compensation circuit includes a first P-type transistor, a first N-type transistor and a compensation resistor, the gate of the first P-type transistor is coupled to the sampling circuit, the drain is grounded, and the source is coupled to the gate of the first N-type transistor, the drain of the first N-type transistor is coupled to the power supply, and the source is coupled to the error amplifier circuit via the compensation resistor.

[0017] As a further improvement of one embodiment of the present invention, the sampling circuit includes an output transistor, a first input transistor, a second input transistor, a first mirroring branch circuit and a second mirroring branch circuit, the first input transistor and the second input transistor are connected in parallel to each other and in series to the first mirroring branch circuit, the output transistor is connected in series to the second mirroring branch circuit, a control end of the first input transistor is connected to the first driving branch circuit of the driving power supply stage, and a control end of the second input transistor is connected to the second driving branch circuit of the driving power supply stage.

[0018] As a further improvement of one embodiment of the present invention, a plurality of the light-emitting elements are provided, forming at least a first light-emitting branch circuit and a second light-emitting branch circuit connected in parallel with each other, the driving power supply stage including at least a first driving branch circuit and a second driving branch circuit, the first light-emitting branch circuit is coupled to the first driving branch circuit to form a first channel, the second light-emitting branch circuit is coupled to the second driving branch circuit to form a second channel, and the first channel and the second channel are connected in parallel.

[0019] As a further improvement of one embodiment of the present invention, the light emitting element driving circuit further includes a current control circuit and a resistor, the control output terminal of the current control circuit is respectively connected to the first driving branch circuit and the second driving branch circuit, and the resistor is connected in series between the input terminal of the current control circuit and ground.

[0020] In order to achieve one of the objectives of the above invention, one embodiment of the present invention provides a light emitting element driving chip including a light emitting element driving circuit provided by the above technical solution, wherein the impedance adjustment module includes a shunt module and a variable resistor module, the light emitting element driving chip further includes a substrate, the variable resistor module, the driving power supply stage and the impedance adjustment branch circuit are disposed on the substrate, the shunt module is disposed outside the substrate, the variable resistor module includes one or more of a variable resistor and an adjustment transistor, and the shunt module includes a shunt resistor. [Effects of the Invention]

[0021] Compared with the prior art, the light emitting element driving circuit provided by the present invention receives the voltages on both sides of the driving power supply stage through the impedance adjustment branch circuit, and accordingly adjusts the impedance of the impedance adjustment module, improving the voltage drop of the driving power supply stage, balancing the power consumption and heat generation of the driving circuit itself, and improving the driving capability of the circuit.

[0022] In an embodiment in which the impedance adjustment module includes a shunt module and a variable resistance module, the shunt state of both can be adjusted according to the voltage drop of the drive power supply stage, and the shunt module can be used to share the heat generated by the drive circuit, thereby further improving the power consumption and heat generation of the drive circuit itself. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a structural schematic diagram of a light-emitting element driving circuit in the prior art; [Figure 2] 2 is a structural schematic diagram of a light-emitting element driving circuit according to an embodiment of the present invention; [Figure 3] 1 is a circuit diagram showing a first example of the light-emitting element driving circuit according to the first embodiment of the present invention; [Figure 4] FIG. 4 is a circuit diagram of a second example of the light-emitting element driving circuit according to the first embodiment of the present invention; [Figure 5] 3 is a circuit diagram showing the structure of a compensation circuit and a sampling circuit portion of the light-emitting element drive circuit according to the first embodiment of the present invention. FIG. [Figure 6] 3 is a circuit diagram showing a first example of the sampling circuit of the light-emitting element driving circuit according to the first embodiment of the present invention; FIG. [Figure 7] FIG. 10 is a circuit diagram of a light-emitting element driving circuit according to a second embodiment of the present invention. [Figure 8] FIG. 10 is a circuit diagram showing a first example of the sampling circuit of the light-emitting element driving circuit according to the second embodiment of the present invention; [Figure 9]FIG. 10 is a circuit diagram of a compensation circuit and a sampling circuit portion of a light-emitting element drive circuit according to a second embodiment of the present invention. [Figure 10] 10 is a circuit diagram of a second example of the sampling circuit of the light-emitting element driving circuit according to one embodiment of the present invention; FIG. [Figure 11] 10 is a schematic diagram illustrating a change in resistance pair value according to a power supply voltage margin during operation of a light-emitting element driving circuit according to an embodiment of the present invention, and a change in current value according to a power supply voltage margin in a branch circuit. [Figure 12] 10 is a schematic diagram illustrating a change in power value according to a power supply voltage margin during operation of a light-emitting element driving circuit according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention will be described in detail below with reference to specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, method or functional modifications made by those skilled in the art according to these embodiments shall fall within the protection scope of the present invention.

[0025] It should be noted that the term "comprises" or any variation thereof is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a set of elements includes not only those elements but also other elements not expressly listed or inherent in such process, method, article, or apparatus. Furthermore, terms such as "first," "second," "third," etc. are used for descriptive purposes only and are not to be understood as denoting or implying relative importance.

[0026] One embodiment of the present invention provides a power consumption device including a light emitting element driving circuit, preferably, the power consumption device further includes a light emitting element, and the light emitting element driving circuit is used to drive the light emitting element on a high side (first embodiment below) or a low side (second embodiment below).

[0027] The light-emitting element may be configured in various options, preferably a commonly used LED (Light-Emitting Diode) or a component derived therefrom, such as an OLED. The light-emitting element may be used in bulk power-using devices such as automobiles, airplanes, and trains. On the one hand, the power-using device may be interpreted as an automobile, airplane, or train, or as a part of the above devices. For example, the power-using device may be interpreted as a headlight lighting device. On the other hand, the light-emitting element may be any one of the light-emitting components driven within the power-using device. In other words, the light-emitting element of the power-using device may have some light-emitting elements driven by the light-emitting element driving circuit and other light-emitting elements driven or controlled by other circuits. The light-emitting element may also be used in other devices, such as a display device. Thus, the power-using device may have various different interpretations and solutions.

[0028] Specifically, the power-consuming device may be a lighting device or a signaling device such as an automobile headlight, an automobile taillight, an interior ambient light, a traffic light, etc. The light-emitting device in these devices may have a multi-channel structure such as 12 channels, 24 channels, or 36 channels. Based on this, the light-emitting device driving circuit provided by the present invention can adaptively realize multi-channel heat dissipation management in consideration of better current driving capability.

[0029] An embodiment of the present invention provides a light emitting element driving chip including a light emitting element driving circuit, wherein the power consuming device may include the light emitting element driving chip to achieve an effect equivalent to that of including the light emitting element driving circuit.

[0030] The light emitting element driving chip comprises several additional features other than the light emitting element driving circuit, which will be described later in terms of a closer correlation between the two. Of course, these additional features can also be understood as being part of the light emitting element driving circuit. Furthermore, many of the embodiments of the light emitting element driving circuit described below can be alternatively implemented in the light emitting element driving chip or the power-using device, resulting in various derivative technical solutions encompassed by the present invention.

[0031] One embodiment of the present invention provides a light emitting device driving circuit as shown in Figure 2. This circuit can be provided in any of the above-mentioned power consumption devices or light emitting device driving chips, or can be implemented independently. The light emitting device driving circuit includes a driving power supply stage 4, an impedance adjustment module 3, and an impedance adjustment branch circuit 5. The driving power supply stage 4 is disposed in the branch circuit where the light emitting device 2 is located, the impedance adjustment module 3 is disposed in the branch circuit where the light emitting device 2 is located, and the impedance adjustment branch circuit 5 is connected in parallel with the driving power supply stage 4. The adjustment output terminal 503 of the impedance adjustment branch circuit 5 is coupled to the impedance adjustment module 3.

[0032] The impedance adjustment branch circuit 5 is configured to adjust the impedance of the impedance adjustment module 3 according to the voltage across the driving power supply stage 4 .

[0033] In this way, the light emitting element driving circuit adjusts the impedance of the impedance adjustment module 3 in the light emitting element driving circuit according to the voltages on both sides of the driving power supply stage 4, especially the voltage drop in the driving power supply stage 4, dynamically improving the voltage drop in the driving power supply stage 4, balancing the power consumption and heat generation of the light emitting element driving circuit itself, and improving the driving capability of the circuit.

[0034] In one embodiment, the impedance adjustment sub-circuit 5 is configured to adjust the impedance of the impedance adjustment module 3 to increase it when the voltage drop in the driving power supply stage 4 is greater than a predetermined compensation voltage value.

[0035] In one embodiment, the impedance adjustment sub-circuit 5 is configured to adjust the impedance of the impedance adjustment module 3 to decrease it when the voltage drop across the driving power supply stage 4 is less than a predetermined compensation voltage value.

[0036] In this way, the voltage drop in the impedance adjustment module 3 is changed to affect the voltage drop in the driving power supply stage 4, thereby adjusting the driving power supply stage 4 to operate in an optimal state so that the voltage drop between its input terminal and output terminal is at least sufficient to drive the light-emitting element 2 for normal operation.

[0037] The above two embodiments may be combined to form a more optimal embodiment, or either one may be selected for configuration. Here, the predetermined compensation voltage value may be dynamically adjusted according to the voltage margin required for the power supply, or may be preset in the impedance adjustment branch circuit 5. In the latter embodiment, the predetermined compensation voltage value may characterize the voltage difference between the driving output terminal 402 and the driving input terminal 401 when the driving power supply stage 4 operates in an optimal state, or may characterize a reasonable voltage difference between the driving output terminal 402 and the driving input terminal 401 allowed for normal operation of the driving power supply stage 4.

[0038] In an embodiment in which the impedance adjustment module 3 includes a shunt module 31 and a variable resistance module 32, as shown in FIG. 3, FIG. 4, or FIG. 7, the shunt module 31 is used to share heat generation, particularly heat generation due to the influence of the voltage margin of the driving power supply stage 4 on at least the included variable resistance module 32. The variable resistance module 32 cooperates with the shunt module 31 to form an input current for the driving power supply stage 4. The driving power supply stage 4 receives the current input and is used to stabilize the driving light-emitting element 2. The impedance adjustment branch circuit 5 is used to adjust the impedance of the variable resistance module 32 and the shunting conditions on the variable resistance module 32 and the shunt module 31.

[0039] Here, the voltage drop across the driving power supply stage 4 is the difference between the voltage value at the driving input terminal 401 of the driving power supply stage 4 and the voltage value at the driving output terminal 402 of the driving power supply stage 4. For example, if the voltage value at the driving output terminal 402 is defined as a first voltage value and the voltage value at the driving input terminal 401 is defined as a second voltage value, the voltage drop across the driving power supply stage 4 can be the difference between the second voltage value and the first voltage value.

[0040] In one embodiment, when the voltage drop in the driving power supply stage 4 (specifically, the difference between the second voltage value and the first voltage value) is greater than a predetermined compensation voltage value, the impedance adjustment branch circuit 5 is configured to adjust the impedance of the impedance adjustment module 3 to continuously increase until the difference between the voltage value of the driving input terminal 401 and the voltage value of the driving output terminal 402 converges to the predetermined compensation voltage value.

[0041] In one embodiment, when the voltage drop in the driving power supply stage 4 is smaller than a predetermined compensation voltage value, the impedance adjustment branch circuit 5 is configured to adjust the impedance of the impedance adjustment module 3 to continuously decrease until the difference between the voltage value of the driving input terminal 401 and the voltage value of the driving output terminal 402 converges to the predetermined compensation voltage value.

[0042] The above two embodiments may be combined to form a more optimal embodiment, or one of them may be selected for configuration.

[0043] In an embodiment in which the impedance adjustment module 3 includes a shunt module 31 and a variable resistor module 32, as shown in FIG. 3, FIG. 4, or FIG. 7, the impedance adjustment is performed to adjust the impedance value of the impedance adjustment module 3 so that the voltage at the driving input terminal 401 is higher than the voltage at the driving output terminal 402, and the difference exceeds at least an optimal value. The impedance value of the impedance adjustment module 3 is then adjusted to increase the total impedance of the impedance adjustment module 3 and reduce the voltage at the driving input terminal 401. Specifically, the impedance value of the variable resistor module 32 is adjusted to reduce the current flowing through the variable resistor module 32 and increase the current shared by the shunt module 31. This reduces the heat generated by the variable resistor module 32 and allows the shunt module 31 to partially share the heat. This improves the self-power consumption and heat generation of the light-emitting element driving circuit. Furthermore, because the impedance value is continuously adjusted, the variable resistor module 32 and the shunt module 31 dynamically follow the operating state of the driving power supply stage 4 and dynamically and constantly maintain the optimal shunt state, allowing the driving power supply stage 4 to operate optimally.

[0044] In the latter embodiment, the total impedance of the impedance adjustment module 3 can be reduced in a timely manner, the shunt state can be adjusted, the current flowing through the variable resistance module 32 can be instantly increased, and the voltage difference between both ends of the driving power supply stage 4 that needs to be adjusted can be restored to an optimal operating state, thereby preventing the occurrence of a voltage or current shortage state and maintaining the performance of the entire light-emitting element driving circuit.

[0045] 3, 4 or 7, the impedance adjustment module 3 includes a shunt module 31 and a variable resistance module 32 connected in parallel to each other. In this way, a mutual shunt function is achieved, and the heat generation between the shunt module 31 and the variable resistance module 32 is balanced to maintain the driving power supply stage 4 in an optimal operating state. Preferably, the shunt module 31 is used to share the heat generation, and in particular, at least a part of the driving circuit including the variable resistance module 32 is used to share the heat generation due to the influence of the voltage margin of the driving power supply stage 4. The variable resistance module 32 is used to adjust the voltage on the driving power supply stage 4 side in cooperation with the shunt module 31.

[0046] Preferably, the variable resistance module 32 includes a variable resistor and / or an N-type transistor and / or a P-type transistor. When an N-type transistor is used, the impedance adjustment sub-circuit 5 can adjust its impedance by controlling its gate voltage. The variable resistance module 32 controls the current flowing therethrough so that it exhibits a positive correlation with the level at its adjustment control end 321. In other words, it is configured to control its self-impedance so that it exhibits a negative correlation with the level at its adjustment control end 321. Preferably, the shunt module 31 may include a shunt resistor, and of course, it may also include an electronic component that has a constant impedance and can share heat or current.

[0047] The adjustment output terminal 503 is coupled to the adjustment control terminal 321 of the variable resistance module 32. The impedance adjustment sub-circuit 5 is configured to adjust the impedance of the variable resistance module 32 according to the voltages on both sides of the driving power supply stage 4. Based on this, it collects the electrical signals of the driving output terminal 402 and the driving input terminal 401 respectively, and adjusts the operation of the adjustment control terminal 321 or adjusts the electrical signal output to the adjustment control terminal 321 according to the situation, thereby affecting the state of the impedance adjustment module 3 and the shunting situation of the variable resistance module 32 and the shunt module 31. Specifically, the impedance adjustment sub-circuit 5 is configured to adjust the impedance value of the variable resistance module 32 according to the first voltage value and the second voltage value.

[0048] When the impedance adjustment branch circuit 5 has an input terminal coupled between the light-emitting element 2 and the driving power supply stage 4, the impedance adjustment branch circuit 5 samples the driving voltage required to light the light-emitting element 2 (in other words, the port of the light-emitting element 2), and accordingly adjusts the impedance situation of the impedance adjustment module 3 in the light-emitting element driving circuit, so that the driving power supply stage 4 operates in a state of minimum voltage drop, improves the power consumption and heat generation due to the voltage margin, and further improves the driving ability of the circuit, so as to meet the driving needs of multi-channel light-emitting elements.

[0049] In one embodiment, the impedance adjustment sub-circuit 5 is configured to adjust the impedance of the variable resistance module 32 to increase, preferably continuously increase, when the voltage drop across the driving power supply stage 4 is greater than a predetermined compensation voltage value.

[0050] In one embodiment, the impedance adjustment sub-circuit 5 is configured to adjust the impedance of the variable resistance module 32 to decrease, preferably continuously decrease, when the voltage drop across the driving power supply stage 4 is less than a predetermined compensation voltage value.

[0051] The above two embodiments may be combined to form a more optimal embodiment, or one of them may be selected for configuration.

[0052] In the light-emitting element driving chip provided by the present invention, the impedance adjustment module 3 includes a shunt module 31 and a variable resistor module 32. The light-emitting element driving chip further includes a substrate 9. The variable resistor module 32, the driving power supply stage 4, and the impedance adjustment branch circuit 5 are mounted on the substrate 9 and packaged, and the substrate 9 may further include a sampling circuit 7 described below. The shunt module 31 may be disposed outside the substrate 9.

[0053] In this way, at least a portion of the impedance adjustment module 3 is located outside the chip, and the heat generated thereby is also at least partially dissipated outside the chip, further preventing the heat dissipation from affecting the operation of the driving power supply stage 4 and other parts within the chip, and using the shunt module 31 to share the current and generate heat while at the same time ensuring high-performance operation of the driving power supply stage 4.

[0054] The light emitting element driving circuit provided by the present invention can also include the above-mentioned shunt module 31 and variable resistor module 32 and be configured to achieve corresponding functions and applications. In addition, in an embodiment in which the shunt module 31 is not disposed off-chip, the performance of the circuit can be improved based on the sharing of heat generation.

[0055] Furthermore, in both the light-emitting element driving chip and the light-emitting element driving circuit, the present invention does not limit the number of shunt modules 31 and variable resistor modules 32, and may include one or more. As a specific option, the variable resistor module 32 includes one or more variable resistors and adjustment transistors, one or more of which are connected in parallel or in series with the shunt module 31 to share current and heat generation and meet more precise adjustment requirements. The shunt module 31 preferably includes a shunt resistor. Of course, the present invention does not exclude the use of an electronic component with a fixed impedance that can share heat generation and current instead of the shunt resistor.

[0056] 11 is a schematic diagram showing the change in circuit parameters due to the power supply voltage margin ΔV, which is simulated by implementing the light-emitting element driving circuit provided by any of the above technical solutions. Here, diagram (a) in FIG. 11 shows the logarithm log of the resistance of the impedance adjustment module 3, the shunt module 31, and the variable resistor module 32 during the operation of the light-emitting element driving circuit. 10 11 shows the change trend of R with respect to the voltage margin ΔV. Diagram (b) in FIG. 11 shows the change trend of the current I at the shunt module 31, the variable resistor module 32, and the drive input terminal 401 of the drive power supply stage with respect to the voltage margin ΔV when the light-emitting element drive circuit is in operation. If the drive input terminal 401 has multiple input terminals, the current I is the sum of the currents at the multiple input terminals. FIG. 12 shows the change status of the power P of the entire system, the shunt module 31 located outside the substrate 9, and the entire substrate 9 with respect to the voltage margin ΔV when the light-emitting element drive circuit is in operation.

[0057] When the power supply voltage margin ΔV increases, the output level of the regulating control terminal 503 decreases, the resistance value of the variable resistance module 32 increases, the current and power shared by the shunt module 31 increase accordingly, the current shared by the variable resistance module 32 decreases, and the heat dissipation performed by the shunt module 31 increases, preventing any impact on the driving power supply stage 4. When the power supply voltage margin ΔV decreases, the output level of the regulating control terminal 503 increases, the resistance value of the variable resistance module 32 decreases, and the current and power shared by the shunt module 31 decrease accordingly, thereby maintaining performance and achieving uniform heat dissipation. Preferably, the impedance adjusting branch circuit 5 continuously adjusts the impedance value of the variable resistance module 32.

[0058] Of course, those skilled in the art can read other change trends from Figures 11 and 12 as the technical effects of the present invention, and summarize the rules to form derivative technical solutions.

[0059] Of course, the above adjustment process can be realized in various embodiments. For example, in one embodiment, the first voltage value and the predetermined compensation voltage value may be added (positive compensation) and then compared with the second voltage value; the second voltage value and the predetermined compensation voltage value may be subtracted (negative compensation) and then compared with the first voltage value; or the second voltage value and the first voltage value may be subtracted and then compared with the difference and the predetermined compensation voltage value. Based on any of the above, an arithmetic circuit including an operational amplifier, an error amplifier, a digital comparator, etc. can be formed, and therefore the above multiple adjustment methods and corresponding circuit structures can be understood to be within the protection scope of the present invention.

[0060] 3, 4 or 7, in this embodiment, the impedance adjustment branch circuit 5 includes a compensation circuit 51 and an error amplifier circuit 52. The compensation circuit 51 stores the predetermined compensation voltage value and compensates the first voltage value positively or the second voltage value negatively. The error amplifier circuit 52 compares the compensated voltage value with another voltage value and adjusts the operation or state of the adjustment control terminal 321 of the variable resistance module 32 according to the comparison result.

[0061] If the impedance adjustment module 3 includes a variable resistance module 32, and the variable resistance module 32 is a transistor, the adjustment control end 321 may be the gate of the transistor. Of course, in other embodiments, the variable resistance module 32 can also be interpreted as part of the impedance adjustment sub-circuit 5.

[0062] Of course, the method for storing the predetermined compensation voltage value in the compensation circuit 51 can be to store the predetermined compensation voltage value in a component such as a capacitor, and directly act on the first voltage value or the second voltage value to generate the voltage input to the error amplifier circuit 52, or to set a constant-value resistor to increase the first voltage value or decrease the second voltage value, and the calculation can be completed through steps such as analog-to-digital conversion, digital calculation, and digital-to-analog conversion.

[0063] The output of the error amplifier circuit 52 is coupled to the impedance adjustment module 3. In an embodiment in which the impedance adjustment module 3 includes a variable resistor module 32, the output of the error amplifier circuit 52 is coupled to an adjustment control terminal 321.

[0064] The first input terminal of the error amplifier circuit 52 is coupled between the driving power supply stage 4 and the light emitting element 2 via the compensation circuit 51. Voltage drop Specifically, the compensation circuit 51 compensates for either the first voltage value or the second voltage value based on the compensation voltage value Vdropout, and outputs the compensated voltage to the error amplifier circuit 52.

[0065] The second input terminal of the error amplifier circuit 52 is coupled to the other terminal of the driving power supply stage 4 that is not coupled to the light-emitting element 2. Specifically, in Figures 3 and 4, the driving output terminal 402 of the driving power supply stage 4 is coupled to the light-emitting element 2, so the second input terminal of the error amplifier circuit 52 is coupled to the driving input terminal 401 of the driving power supply stage 4, and in Figure 7, the driving input terminal 401 of the driving power supply stage 4 is coupled to the light-emitting element 2, so the second input terminal of the error amplifier circuit 52 is coupled to the driving output terminal 402 of the driving power supply stage 4.

[0066] The light-emitting element driving circuit further includes a sampling circuit 7. The error amplifier circuit 52 is coupled between the driving power supply stage 4 and the light-emitting element 2 via the compensation circuit 51 and the sampling circuit 7. Furthermore, the branch circuit formed by the error amplifier circuit 52, the compensation circuit 51, and the sampling circuit 7 and the branch circuit formed by the driving power supply stage 4 and the light-emitting element 2 are coupled in a connection relationship such that a large number of nodes can be formed.

[0067] The sampling circuit 7 is configured to collect voltage extreme values ​​at a node between the driving power supply stage 4 and the light emitting element 2. The voltage extreme values ​​include at least one of a maximum voltage value and a minimum voltage value. The compensation circuit 51 having a predetermined compensation voltage value The voltage extremes are compensated for in response to a compensation voltage.

[0068] In a first embodiment of the sampling circuit 7 provided by FIG. 6 or FIG. 8, the sampling circuit 7 may include an output transistor 713 , a plurality of input transistors 714 , a first mirroring branch circuit 711 and a second mirroring branch circuit 712 .

[0069] The output transistor 713 is connected in series to the second mirroring branch circuit 712. Specifically, the input transistor 714 may include a first input transistor 7141 and a second input transistor 7142, where the first input transistor 7141 and the second input transistor 7142 are connected in parallel with each other, the first input transistor 7141 is connected in series with the first mirroring branch circuit 711, and the second input transistor 7142 is connected in series with the first mirroring branch circuit 711. In this way, the transistors can be used to complete the voltage screening and mirroring process from the driving power supply stage 4 to the impedance adjustment branch circuit 5.

[0070] The control terminal of the first input transistor 7141 is connected to, specifically to the input terminal of, the first driving branch circuit 41 in the driving power supply stage 4, and the control terminal of the second input transistor 7142 is connected to, specifically to the input terminal of, the second driving branch circuit 42 in the driving power supply stage 4. In this way, sampling of voltage extremes is realized.

[0071] 3, 4 or 7, in an application scenario, at least two sets of light-emitting elements 2 are provided at the rear end of the driving power supply stage 4, and correspondingly, the driving power supply stage 4 includes at least two sets of driving branch circuits 40, and each of the at least two sets of driving branch circuits 40 is connected in series to correspond to at least two sets of light-emitting elements 2, and multiple light-emitting channels formed by the driving branch circuits 40 and the corresponding light-emitting elements 2 (or light-emitting branch circuits 20) are connected in parallel to each other on the driving power supply stage 4 side. In this way, it is possible to adapt to driving light-emitting elements in multiple light-emitting channels.

[0072] A plurality of light-emitting elements 2 (specifically, LEDs) are connected in series on a single light-emitting branch circuit 20, and a plurality of light-emitting branch circuits 20 are provided on the side of the driving power supply stage 4. For example, the driving power supply stage 4 includes at least a first driving branch circuit 41 and a second driving branch circuit 42, and the light-emitting branch circuit 20 includes at least the first light-emitting branch circuit 21 and the second light-emitting branch circuit 22 connected in parallel to each other. Here, the first driving branch circuit 41 and the second driving branch circuit 42 are used to drive the light-emitting branch circuits 20 correspondingly. Each driving branch circuit 40 may include a current source and / or a voltage source.

[0073] The first light-emitting branch circuit 21 is coupled to the first driving branch circuit 41 to form a first channel, and the second light-emitting branch circuit 22 is coupled to the second driving branch circuit 42 to form a second channel, with the first and second channels connected in parallel to each other to achieve corresponding light-emitting functions. The present invention does not exclude various timing adjustments for lighting the light-emitting element 2, and all resulting improvements and technical effects are included in the present invention. The present invention does not limit the number of channels, and may include a third channel, a fourth channel, etc., or only the first channel. When multiple channels are included, multiple driving input terminals 401 may be included, and the connection to the driving input terminal 401 may be a connection to one or more of them, and the driving output terminal 402 can be understood similarly. Of course, the process of collecting the sampled voltage may be the result obtained by collecting and comparing the voltages on all the channels.

[0074] In order to adapt to the needs of different light-emitting branch circuits 20, alongside the sampling circuit 7, the light-emitting element driving circuit may further include a current control circuit 61 and a configuration resistor 62, which are respectively used to control the driving current of each of the light-emitting channels and further to adjust the global range of the driving current.

[0075] Specifically, the control output terminals 611 of the current control circuit 61 are respectively connected to the drive branch circuits 40. In an embodiment including multiple sets of the drive branch circuits 40, when each set includes at least one current source, the control output terminals 611 are respectively connected to the current source or voltage source in the drive branch circuits 40, while the control output terminals 611 are respectively connected to the first drive branch circuit 41 and the second drive branch circuit 42.

[0076] Based on this, a plurality of the control output terminals 611 are included, each of which is connected to a corresponding one of the current sources to provide a current limiting control signal, and the configuration input terminal 612 of the current control circuit 6 is grounded via a configuration resistor 62. Thereby, it is possible to adapt to the needs of different light-emitting branch circuits 20, and to replace or adjust the resistance value of the configuration resistor 62, and cooperate with the current control circuit 61 to configure global control of the current on the channel.

[0077] Here, the control output terminals 611 are provided corresponding to the channels, the driving branch circuits, or the current sources in the driving branch circuits, and may have the same number between them. Preferably, the numbers of the light-emitting branch circuits 20, the driving branch circuits 40, and the control output terminals 611 may be the same.

[0078] Hereinafter, the first and second embodiments of the present invention are further provided.

[0079] In a first embodiment provided by the present invention, as shown in Figures 3 to 6, the light emitting element 2 is coupled to the driving output terminal 402 of the driving power supply stage 4. The sampling circuit 7 is configured to collect a sampling voltage having a maximum voltage value at the driving input terminal 401. The compensation circuit 51 is configured to positively compensate the sampling voltage according to the compensation voltage Vdropout.

[0080] In the first embodiment provided by the present invention, the impedance adjustment module 3 is connected in series between the power supply terminal 82 and the driving input terminal 401 of the driving power supply stage 4. The light-emitting element 2 is connected in series between the driving output terminal 402 of the driving power supply stage 4 and ground GND. The compensation circuit 51 includes a first N-type transistor 511, a first P-type transistor 512, and a compensation resistor 515.

[0081] In the first embodiment, the gate of the first N-type transistor 511 is coupled to the sampling circuit 7, the drain of the first N-type transistor 511 is coupled to the power supply level VCC (specifically, the power supply terminal 82), and the source of the first N-type transistor 511 is coupled to the gate of the first P-type transistor 512. The drain of the first P-type transistor 512 is grounded to GND, and the source of the first P-type transistor 512 is coupled to the error amplifier circuit 52 via a compensation resistor 515.

[0082] In the first embodiment, one end of the shunt module 31 is connected to the power supply terminal 82 and the other end is connected to the driving input terminal 401 of the driving power supply stage 4, one end of the variable resistance module 32 is connected to the power supply terminal 82 and the other end is connected to the driving input terminal 401 of the driving power supply stage 4, and the shunt module 31 and the variable resistance module 32 are connected in parallel. The driving output terminal 402 of the driving power supply stage 4 is connected to the light emitting device 2, and the input current jointly generated after shunting is adjusted and then output to the light emitting device 2, thereby achieving the effect of driving the light emitting device 2.

[0083] Furthermore, the impedance adjustment branch circuit 5 includes a sampling input terminal 501, a reference input terminal 502, and an adjustment output terminal 503. Here, the sampling input terminal 501 is connected to the driving output terminal 402, and the reference input terminal 502 is connected to the driving input terminal 401.

[0084] The "input end" and "output end" may be defined as "input side" and "output side," respectively. This definition is not intended to limit the specific form or structure. Considering the presence of multiple ports arranged in parallel at the location of the structure, the above connection relationships are applicable to each other. For example, in one embodiment, multiple variable resistance modules 32 are connected in series or in parallel with each other between the power supply terminal 82 and the driving power supply stage 4. In this case, the regulated output side may include multiple corresponding regulated output terminals 503, which are respectively connected to multiple regulated control terminals 321 of the multiple variable resistance modules 32 to control the multiple variable resistance modules 32. If the light-emitting device 2 arranged in the driving power supply stage 4 corresponding to multiple channels includes multiple sets of driving branch circuits, the driving input side and the driving output side may similarly have other structural or connection arrangements that are conceivable to those skilled in the art.

[0085] In the first embodiment, the first input terminal of the error amplifier circuit 52 is connected to the driving output terminal 402 by being directly used as the sampling input terminal 501 or being connected to the sampling input terminal 501, and the second input terminal of the error amplifier circuit 52 is connected to the driving input terminal 401 by being directly used as the reference input terminal 502 or being connected to the reference input terminal 502.

[0086] Specifically, when the compensation circuit 51 is disposed between the first input terminal of the error amplifier circuit 52 and the drive output terminal 402, the compensation circuit 51 is connected to one side of the drive output terminal 402 and used as a sampling input terminal 501, and the compensation circuit 51 collects the first voltage value and performs an addition operation (positive compensation) on the first voltage value according to the predetermined compensation voltage value to generate the third voltage value, which is output to the error amplifier circuit 52 for comparison. When the compensation circuit 51 is disposed between the second input terminal of the error amplifier circuit 52 and the drive input terminal 401, the compensation circuit 51 is connected to one side of the drive input terminal 401 and used as a reference input terminal 502, and the compensation circuit 51 collects the second voltage value and performs a subtraction operation (negative compensation) on the second voltage value according to the predetermined compensation voltage value to generate the third voltage value, which is output to the error amplifier circuit 52 for comparison.

[0087] 3 , the inverting input terminal of the error amplifier circuit 52 functions as the first input terminal. The first input terminal is connected to the driving output terminal 402 via the compensation circuit 51. The non-inverting input terminal of the error amplifier circuit 52 functions as the second input terminal. The second input terminal is directly connected to the driving input terminal 401 as the reference input terminal 502. In this way, when the second voltage value is greater than the sum of the first voltage value and the predetermined compensation voltage value, the error amplifier circuit 52 amplifies the comparison result and outputs a control signal of increasing level to the adjustment control terminal 321, so as to control the impedance value of the variable resistance module 32 to continuously increase; and / or when the sum of the first voltage value and the predetermined compensation voltage value is greater than the second voltage value, the error amplifier circuit 52 amplifies the comparison result and outputs a control signal of decreasing level to the adjustment control terminal 321, so as to control the impedance value of the variable resistance module 32 to continuously decrease. Preferably, the variable resistance module 32 includes a variable resistance and / or a P-type transistor, and controls the resistance value of the variable resistance and / or the P-type transistor to increase after the adjustment control terminal 321 receives a control signal whose level increases, and / or controls the resistance value of the variable resistance and / or the P-type transistor to decrease after the adjustment control terminal 321 receives a control signal whose level decreases.

[0088] 4, the non-inverting input terminal of the error amplifier circuit 52 functions as the first input terminal. The first input terminal is connected to the driving output terminal 402 via the compensation circuit 51. The inverting input terminal of the error amplifier circuit 52 functions as the second input terminal. The second input terminal is directly connected to the driving input terminal 401 as the reference input terminal 502. If the second voltage value is greater than the sum of the first voltage value and the predetermined compensation voltage value, the error amplifier circuit 52 amplifies the comparison result and outputs a control signal of decreasing level to the adjustment control terminal 321 to control the impedance value of the variable resistance module 32 to continuously increase; and / or if the sum of the first voltage value and the predetermined compensation voltage value is greater than the second voltage value, the error amplifier circuit 52 amplifies the comparison result and outputs a control signal of increasing level to the adjustment control terminal 321 to control the impedance value of the variable resistance module 32 to continuously decrease. Preferably, the variable resistance module 32 includes an N-type transistor, and controls the N-type transistor to increase its internal resistance value after the adjustment control terminal 321 receives a control signal whose level decreases, and / or controls the N-type transistor to decrease its internal resistance value after the adjustment control terminal 321 receives a control signal whose level increases.

[0089] In the first embodiment, the compensation circuit 51 may include a first N-type transistor 511, a first P-type transistor 512, a first current source 513, a second current source 514, and a compensation resistor 515. Here, the first N-type transistor 511 and the first P-type transistor 512 may be field-effect transistors, and are used to hold and transmit the first voltage value from the sampling input terminal 501 and apply it to the compensation resistor 515. The first current source 513 and the second current source 514 are used to generate bias currents corresponding to the first N-type transistor 511 and the first P-type transistor 512, respectively. The compensation resistor 515 is used to generate a compensation voltage Vdropout having the predetermined compensation voltage value at both ends, and to pull up the voltage corresponding to the first voltage value formed at one end of the compensation resistor 515 and output it to the error amplifier circuit 52.

[0090] Furthermore, the gate of the first N-type transistor 511 is connected to the driving output terminal 402 as the sampling input terminal 501, the drain of the first N-type transistor 511 is connected to an internal level (which may be the power supply level VCC or may be the power supply terminal 82), and the source of the first N-type transistor 511 is connected to the gate of the first P-type transistor 512 and ground GND, respectively. The drain of the first P-type transistor 512 is connected to ground GND, and the source of the first P-type transistor 512 is connected to the error amplifier circuit 52.

[0091] Preferably, a first current source 513 is connected in series between the source of the first N-type transistor 511 and ground GND, and a second current source 512 is connected in series between the drain of the first P-type transistor 512 and ground GND, respectively supplying the same or different bias currents to the first N-type transistor 511 and the first P-type transistor 512. At the same time, a compensation resistor 515 is connected in series between the source of the first P-type transistor 512 and the error amplifier circuit 52 to form a compensation voltage Vdropout.

[0092] It should be noted that the transistor arrangement is merely one preferred embodiment of the compensation circuit 51, and the desired technical effect can be achieved to some extent even if the transistors are replaced with switch tubes such as triodes or other electronic components.

[0093] The driving output end 402 may be provided with a plurality of driving terminals corresponding to the driving branch circuit 40, and the light emitting element 2 is connected to the driving terminals and cooperates with them to be driven by the driving current.

[0094] The first control output terminal in the control output terminal 611 is connected to at least one current source on the first driving branch circuit 41, and the first driving branch circuit 41 is connected to the first light-emitting branch circuit 21 via the first driving output terminal in the driving output terminal 402, and a plurality of light-emitting elements 2 are connected in series on the first light-emitting branch circuit 21, and the negative pole of the light-emitting element 2 farthest from the driving output terminal 402 is connected to ground GND. The second driving branch circuit 42 and the second light-emitting branch circuit 22 have the same structural arrangement as above, so they will not be repeated here.

[0095] After the plurality of sets of channels are formed, the maximum voltage value on the multiple channels can be calculated as the first voltage value, so that the light emitting device driving circuit can improve the voltage and heat generation control and distribution. Based on this, the light emitting device driving circuit may include the sampling circuit 7, and specifically, the sampling circuit 7 is disposed between the impedance adjustment branch circuit 6 and the driving output terminal 402, and is configured to sample the maximum sampled voltage on the driving output terminal 402 as the first voltage value.

[0096] Meanwhile, the sampling circuit 7 can be similarly applied to an embodiment that specifically defines the structure of the compensation circuit 51. In this embodiment, the compensation circuit 51 is disposed between the sampling circuit 7 and the error amplifier circuit 52. Specifically, it is disposed between the driving output terminal 402 and the first input terminal of the error amplifier circuit 52, and the sampling circuit 7 is disposed between the compensation circuit 51 and the driving output terminal 402, and transmits the first voltage value after screening to the compensation circuit 51 via the sampling input terminal 501.

[0097] Furthermore, the gate of the first N-type transistor 511 may be connected to the output terminal of the sampling circuit 7 to obtain the first voltage value after screening. The above connection is not limited to a direct connection. If the sampling circuit 7 does not have a voltage holding structure, a holding circuit 73 may be further disposed between the sampling circuit 7 and the compensation circuit 51, and the holding circuit 73 may include a follower switch connected in series between the output terminal of the sampling circuit 7 and the sampling input terminal 501, and a holding capacitor with one end connected between the above two terminals and the other end grounded. Of course, any holding circuit structure configuration that can be anticipated by those skilled in the art and performs a similar function is within the protection scope of the present invention.

[0098] On the other hand, a second embodiment of the specific structure of the sampling circuit 7 may have the structural arrangement shown in Figure 10. In this embodiment, the sampling circuit 7 includes an analog-to-digital converter 721, a digital comparator 722, a register 723, and a digital-to-analog converter 724 connected in series, the input terminal of the analog-to-digital converter 721 is connected to the driving output terminal 402 of the driving power supply stage 4, and the output terminal of the digital-to-analog converter 724 is connected to the sampling input terminal 501. Here, the analog-to-digital converter 721 is used to receive and convert the voltage values ​​of the multiplexed channels into digital quantities, the digital comparator 722 is used to compare and screen the multiple digital voltage quantities on the driving output terminal 402 of the multiplexed channels to obtain a maximum digital voltage value, the register 723 is used to store the maximum digital voltage value, and the digital-to-analog converter 724 is used to convert the maximum digital voltage value into an analog quantity to obtain a voltage having a first voltage value and output the voltage.

[0099] The control ends of the at least two input transistors 714 are respectively connected to the driving output ends 402 of the at least two sets of driving branch circuits 40, and the at least two input transistors 714 are connected in parallel with each other and in series between the first mirroring branch circuit 711 and the reference ground terminal GND. The output transistor 713 is connected in series between the second mirroring branch circuit 712 and the reference ground terminal GND, and the control ends of the output transistor 713 are respectively connected to the input terminal of the output transistor 713 and the sampling input terminal 501. Preferably, the sampling circuit 7 may further include a voltage adjustment capacitor having one end connected to the control end of the output transistor 713 and the other end grounded.

[0100] Specifically, the input transistor 714 includes a first input transistor 7141 and a second input transistor 7142, the control terminal of the first input transistor 7141 is connected to the first driving output terminal, and the control terminal of the second input transistor 7142 is connected to the second driving output terminal corresponding to the second driving branch circuit 42. The input transistor 714 receives the voltage values ​​of the driving output terminals 402 of the two channels. If the voltage value of the first driving output terminal is greater than the voltage value of the second driving output terminal, the input transistor 714 selects the first input transistor 7141 and closes the second input transistor 7142. The first mirroring branch circuit 711 mirrors the control terminal voltage of the first input transistor 7141 to the control terminal of the output transistor 713, generating and outputting a voltage having a first voltage value. In this way, the voltage value screening step can be completed efficiently.

[0101] In one embodiment, the input transistor 714 and the output transistor 713 are configured with the same selection type, preferably an N-type field effect transistor, and the first mirroring branch circuit 711 and the second mirroring branch circuit 712 each include a first mirroring transistor and a second mirroring transistor, respectively, and the first mirroring transistor and the second mirroring transistor are configured with the same selection type, preferably a P-type field effect transistor. Based on this, the control end may be specifically defined as the gate of the N-type field effect transistor or the gate of the P-type field effect transistor, the input end may be specifically defined as the drain of the N-type field effect transistor or the source of the P-type field effect transistor, and the output end may be specifically defined as the source of the N-type field effect transistor or the drain of the P-type field effect transistor.

[0102] In summary, in the first embodiment provided by the present invention, the impedance adjusting branch circuit receives the voltage values ​​from the driving output terminal and the driving input terminal respectively, and adjusts the impedance of the adjusting unit connected in parallel with the shunt unit and arranged before the driving input terminal based on the two voltage values, adjusts the shunting resistance and the shunting state of the adjusting unit according to the actual voltage situation, balances the power situations of the shunt unit and the adjusting unit, and uses the shunt resistance to share the heat generation of the driving circuit, avoids the problems of excessive power and high power consumption of the light emitting element driving circuit itself, adapts to various light emitting element strings, achieves stable driving, and achieves the technical effects of improving driving efficiency and driving current capacity.

[0103] In a second embodiment provided by the present invention, as shown in Figures 7 to 9, a light emitting element 2 is coupled to a driving input terminal 401 of a driving power supply stage 4. A sampling circuit 7 is configured to collect a sampling voltage having a minimum voltage value at the driving input terminal 401. A compensation circuit 51 is configured to negatively compensate the sampling voltage according to the compensation voltage Vdropout.

[0104] In a second embodiment provided by the present invention, the impedance adjustment module 3 is connected in series between the driving output terminal 402 of the driving power supply stage 4 and ground GND. The light-emitting element 2 is connected in series between the power supply terminal 82 and the driving input terminal 401 of the driving power supply stage 4. The compensation circuit 51 includes a first P-type transistor 512, a first N-type transistor 511, and a compensation resistor 515.

[0105] In the second embodiment, the gate of first P-type transistor 512 is coupled to sampling circuit 7, the drain of first P-type transistor 512 is connected to ground GND, and the source of first P-type transistor 512 is coupled to the gate of first N-type transistor 511. The drain of first N-type transistor 511 is coupled to power supply level VCC (specifically, power supply terminal 82), and the source of first N-type transistor 511 is coupled to error amplifier circuit 52 via compensation resistor 515.

[0106] In the second embodiment, the light emitting element driving circuit includes a driving power supply stage 4 and an impedance adjustment module 3 arranged between the light emitting element 2 and a ground terminal 81. Note that any connection relationship with the ground GND can be interpreted as a connection relationship with the ground terminal 81.

[0107] Preferably, the light-emitting element driving circuit further includes an impedance adjustment branch circuit 5, which is connected in parallel to the driving power supply stage 4 via a sampling input terminal 501 and a reference input terminal 502. In other words, one end of the driving power supply stage 4 may be connected to the sampling input terminal 501 of the impedance adjustment branch circuit 5, and the other end may be connected to the reference input terminal 502 of the impedance adjustment branch circuit 5.

[0108] In the second embodiment, the driving power supply stage 4 is positioned closer to the ground terminal 81 of the light-emitting element 2 (in other words, the driving power supply stage 4 is connected to the output port of the light-emitting element 2), thereby realizing low-side driving of the light-emitting element 2, making the design of the driving circuit more compact and enabling better cost control.

[0109] In the second embodiment, the driving power supply stage 4 is used to adjust and stabilize the current on the light-emitting element 2 on the low side. The impedance adjustment branch circuit 5 is configured to adjust the impedance of the impedance adjustment module 3, specifically configured to adjust the resistance value in the circuit of the impedance adjustment module 3. The impedance adjustment module 3 is used to controllably adjust the impedance, affect the branch circuit current and / or share some of the heat generation, and prevent excessive impact on the driving power supply stage 4. Preferably, the light-emitting element 2, the driving power supply stage 4, the impedance adjustment module 3 and the ground terminal 81 are connected in series.

[0110] The sampling input terminal 501 and the reference input terminal 502 can be interpreted as terminals for receiving a voltage or current signal on the impedance matching branch circuit 5. Preferably, the impedance matching branch circuit 5 can use the voltage at the reference input terminal 502 as a reference, calculate this reference using the voltage on the sampling input terminal 501, and adjust the impedance matching module 3 according to the calculation result. The adjustment control terminal 503 can be interpreted as an output terminal on the impedance matching branch circuit 5 for outputting the calculation result.

[0111] The ground terminal 81 is used to connect to the ground GND. For example, it may be a common ground of an automotive lighting device, and one terminal of the light-emitting element 2 may be connected to the power supply terminal 82 correspondingly. Here, the ground terminal and the power supply terminal may be interpreted as parts of the light-emitting element driving circuit, or may be interpreted as terminals for supplying ground GND or power to the light-emitting element driving circuit rather than as parts of the circuit.

[0112] The substrate 9 may include an on-chip load terminal 91 and an on-chip ground terminal 92. Preferably, the on-chip load terminal 91 is connected to the power supply terminal 82 via the light emitting element 2. In this case, the power supply terminal 82 and the light emitting element 2 may not be included in the light emitting element driving circuit. The number of on-chip load terminals 91 may be equal to the number of light emitting channels formed by the light emitting elements 2. Preferably, the on-chip ground terminal 92 is connected to the ground terminal 81 directly or via a shunt module 31 arranged off-chip, and is further connected to the ground terminal GND. The number of on-chip ground terminals 92 may be equal to the total number of shunt modules 31 and variable resistance modules 32.

[0113] Based on the above description, it should be reiterated that, according to different relationships between the power supply terminal and the ground terminal and the light-emitting element driving circuit, the power supply terminal for accessing a power supply or other high level can be interpreted as one of the power supply terminal 82 or the on-chip load terminal 91, and the ground terminal for accessing ground GND can be interpreted as one of the ground terminal 81 or the on-chip ground terminal 92.

[0114] In the second embodiment, the shunt module 31 is connected in series between the ground terminal 81 and the driving power supply stage 4, and the variable resistor module 32 is connected in series between the ground terminal 81 and the driving power supply stage 4. In this way, the accuracy and timeliness of the adaptive dynamic adjustment are maintained. Even if the shunt module 31 is located off-chip, wiring is also somewhat simplified.

[0115] In embodiments including compensation circuit 51 , the compensated voltage is output to error amplifier circuit 52 , which is used to compare the compensated voltage with the voltage at drive output 402 .

[0116] In the second embodiment, the light emitting element driving circuit includes a sampling circuit 7, and the error amplifier circuit 52 is further indirectly connected to the driving input terminal 401 via two parts, the compensation circuit 51 and the sampling circuit 7. Preferably, the sampling circuit 7 is configured to collect the sampling voltage with the smallest voltage value on the driving input terminal 401 and output it to the compensation circuit 51. The "sampling voltage with the smallest voltage value" refers to the one of the multiple channels with the smallest voltage value on the driving input terminal 401 side when the driving power supply stage 4 and the light emitting element 2 jointly form multiple channels. In other words, the sampling circuit 7 may be configured to have the function of screening channel voltages.

[0117] Preferably, the compensation circuit 51 is configured to negatively compensate the sampling voltage in response to the compensation voltage Vdropout. LED_MIN , the voltage output from the compensation circuit 51 to the error amplifier circuit 52 is V GND_REF When defined as, the sampling voltage V LED_MIN and voltage V GND_REF is at least V GND_REF =V LED_MIN -Vdropout Meet the following.

[0118] The voltage of the driving output terminal 402 is V GND_LED The error amplifier circuit 52 outputs a voltage V GND_LED and voltage V GND_REF , i.e., voltage V GND_LED and voltage V LED_MIN Compare with -Vdropout. V GND_LED >V LED_MIN When -Vdropout is satisfied, the conduction voltage drop on the driving power supply stage 4 is smaller than the predetermined compensation voltage Vdropout, the voltage of the driving power supply stage 4 is insufficient, the output voltage of the error amplifier circuit 52 increases, the voltage of the adjustment control terminal 321 increases, and the resistance value of the variable resistor module 32 decreases. GND_LED <V LED_MINWhen −Vdropout is satisfied, the conduction voltage drop on the driving power supply stage 4 is greater than the compensation voltage Vdropout, the power consumption of the driving power supply stage 4 is high, the voltage of the regulating control terminal 321 decreases, the resistance value of the variable resistance module 32 increases, and the shunt module 31 bears a certain amount of power consumption.

[0119] When the error amplifier circuit 52 is interpreted as an error amplifier or includes an error amplifier, the input connected to the compensation circuit 51 and its associated branch circuits can be interpreted as the inverting input of the error amplifier, and the input connected to the driving output 402 and its associated branch circuits can be interpreted as the non-inverting input of the error amplifier. Furthermore, the non-inverting input can be directly used as the reference input 502.

[0120] In the second embodiment, the sampling circuit 7 is disposed between the impedance matching sub-circuit 5 and the driving input terminal 401. The sampling circuit 7 is preferably configured to collect a sampled voltage with a minimum voltage value on the driving input terminal 401 and output the sampled voltage to the impedance matching sub-circuit 5. In this way, the impedance state of the impedance matching module 3 is adaptively adjusted according to the sampled voltage.

[0121] The sampling circuit 7 may include a plurality of input transistors 714, each connected via its control terminal to a corresponding one of the driving branch circuits (or the driving input terminal 401). Preferably, the number of input transistors 714, the number of driving branch circuits 40, and the number of light-emitting branch circuits 20 are configured to be equal.

[0122] In this second embodiment, when the voltage value at the input end of the first driving branch circuit 41 is smaller than the voltage value at the input end of the driving branch circuits such as the second driving branch circuit 42, the first input transistor 7141 is conductive and the second input transistor 7142 is closed, and within the limit of the transistor conduction degree, the first mirroring branch circuit 711 mirrors the control end voltage of the first input transistor 7141 to the control end of the output transistor 713. In this way, the voltage minimum screening process is efficiently completed and the sampling voltage is generated.

[0123] Preferably, the input transistor 714 and the output transistor 713 are configured with the same selection type, preferably a P-type field effect transistor. The first mirroring branch circuit 711 and the second mirroring branch circuit 712 preferably include a first mirroring transistor and a second mirroring transistor, preferably an N-type field effect transistor. Based on this, the control end is defined as the gate of the transistor or the field effect transistor, and the field effect transistor or the transistor is connected in series to different branches via its gate and source.

[0124] Preferably, the sources of the input transistors 714 are connected to each other and to the power supply level VCC (or the power supply terminal 82), the drains are connected to each other and to the drain of the first mirroring transistor, and the source of the first mirroring transistor is grounded. The source of the output transistor is connected to the power supply level VCC, the drain is connected to the drain of the second mirroring transistor, and the source of the second mirroring transistor is grounded. The gates of the first mirroring transistor and the second mirroring transistor are connected to each other, and the drain of the first mirroring transistor is connected to its own gate. The gate of the output transistor 713 is connected to the sampling input terminal 501 and its own drain. A voltage adjustment capacitor may be further connected in series between the gate of the output transistor 713 and ground GND.

[0125] 10 , the sampling circuit 7 specifically includes an analog-to-digital converter 721, a digital comparator 722, a register 723, and a digital-to-analog converter 724, which are sequentially connected between the driving power supply stage 4 (specifically, the driving input terminal 401) and the impedance adjustment circuit 5 (specifically, the sampling input terminal 501). The analog-to-digital converter 721 receives and converts the voltage values ​​of the multiplexed light-emitting channels into digital quantities, and may include multiple digital comparators. The digital comparators 722 compare and screen the digital voltage values ​​on the driving input terminals 401 of the multiplexed light-emitting channels to obtain the minimum sampled voltage. The register 723 stores the sampled voltage values. The digital-to-analog converter 724 converts and acquires the sampled voltage values ​​into analog quantities, and outputs the sampled voltages.

[0126] The compensation circuit 51 in any of the above embodiments may have a preferred structural design as shown in Figure 9. For example, the compensation circuit 51 may include a first P-type transistor 512, a first N-type transistor 511, and a compensation resistor 515. Here, the gate of the first P-type transistor 512 is connected to the sampling circuit 7 and connected to the driving output terminal 402 via the sampling circuit 7, the drain of the first P-type transistor 512 is grounded, and the source of the first P-type transistor 512 is connected to the gate of the first N-type transistor 511. The drain of the first N-type transistor 511 may be connected to a high level, preferably to the power supply level VCC (or the power supply terminal 82), and the source of the first N-type transistor 511 is connected to the error amplifier circuit 52 via the compensation resistor 515.

[0127] In this way, the sampling voltage can be negatively compensated by the compensation voltage Vdropout formed by the power supply level VCC (particularly the first current source 513 described below) acting on the compensation resistor 515. Here, a first P-type transistor 512 and a first N-type transistor 511 are used to hold and transfer the sampling voltage from the sampling input terminal 501 and apply it to one end of the compensation resistor 515. The two transistors are preferably configured as field effect transistors.

[0128] A second current source 514 for generating a bias current may be further arranged between the first P-type transistor 512 and the power supply level VCC. A first current source 513 for generating a bias current may be further arranged between the first N-type transistor 511 and the power supply level VCC. With the above components arranged, a compensation resistor 515 drops the voltage value of the sampling voltage by the voltage value of the compensation voltage Vdropout to obtain a voltage output for comparison by the error amplifier circuit 52. Of course, this may be realized by replacing it with another subtraction circuit.

[0129] A holding circuit 73 may be further disposed between the sampling circuit 7 and the compensation circuit 51, and the holding circuit 73 includes a follower switch connected in series between the output terminal of the sampling circuit 7 and the sampling input terminal 501, and a holding capacitor with one end connected between the above two terminals and the other end grounded. Of course, any holding circuit structure configuration that can be foreseen by a person skilled in the art and that performs a similar function is within the scope of protection of the present invention.

[0130] As described above, the light-emitting element driving circuit provided in the second embodiment adopts a low-side driving method that can be used in bulk power-using devices such as automobiles and airplanes, and adjusts the impedance of the impedance adjustment module through the impedance adjustment circuit to balance the power consumption and heat generation of the driving circuit itself, thereby improving the driving capability of the circuit.

[0131] As described above, the light emitting device driving circuit provided by the present invention receives the voltages on both sides of the driving power supply stage via the impedance adjustment branch circuit and adjusts the impedance of the impedance adjustment module based on this, thereby improving the voltage drop of the driving power supply stage, balancing the power consumption and heat generation of the driving circuit itself, and improving the driving capability of the circuit. In an embodiment in which the impedance adjustment module includes a shunt module and a variable resistor module, the shunt state of the two modules can be adjusted according to the voltage drop of the driving power supply stage, and the shunt module can be used to share the heat generation of the driving circuit, further improving the power consumption and heat generation of the driving circuit itself.

[0132] Although this specification is described based on embodiments, each embodiment does not include only independent technical solutions, and the description in this specification is for the purpose of clarity, and those skilled in the art should take this specification as a whole, and it should be understood that the technical solutions of the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0133] The above series of detailed descriptions are merely specific descriptions of the feasible embodiments of the present invention, and are not intended to limit the protection scope of the present invention; any equivalent embodiments or modifications obtained without departing from the spirit of the present invention shall be included within the protection scope of the present invention.

Claims

1. a driving power supply stage connected to the light emitting device, an impedance adjustment module, and an impedance adjustment branch circuit connected in parallel to the driving power supply stage, wherein the adjustment output end of the impedance adjustment branch circuit is coupled to the impedance adjustment module; The impedance adjustment branch circuit is configured to adjust the impedance of the impedance adjustment module according to the voltage across the driving power supply stage; a first input terminal of the error amplifier circuit coupled between the driving power supply stage and the light-emitting element via the compensation circuit; a second input terminal of the error amplifier circuit coupled to the other end of the driving power supply stage that is not coupled to the light-emitting element; and the compensation circuit configured to compensate for a voltage drop in the driving power supply stage.

2. The light-emitting element driving circuit of claim 1, characterized in that the impedance adjustment branch circuit is configured to adjust the impedance of the impedance adjustment module to increase when the voltage drop of the driving power supply stage is greater than a predetermined compensation voltage value, and / or the impedance adjustment branch circuit is configured to adjust the impedance of the impedance adjustment module to decrease when the voltage drop of the driving power supply stage is less than the predetermined compensation voltage value.

3. The voltage drop of the driving power supply stage is the difference between the voltage value at the driving input end of the driving power supply stage and the voltage value at its driving output end; The impedance adjustment branch circuit is configured to adjust the impedance of the impedance adjustment module to continuously increase until the difference between the drive input terminal voltage value and the drive output terminal voltage value converges to the predetermined compensation voltage value when the voltage drop of the drive power supply stage is greater than the predetermined compensation voltage value; 3. The light-emitting element driving circuit according to claim 2, wherein the impedance adjustment branch circuit is configured to adjust the impedance of the impedance adjustment module to continuously decrease until the difference between the driving input terminal voltage value and the driving output terminal voltage value converges to the predetermined compensation voltage value when the voltage drop of the driving power supply stage is smaller than the predetermined compensation voltage value.

4. 3. The light-emitting element driving circuit according to claim 2, wherein the impedance adjustment module includes a shunt module and a variable resistor module connected in parallel with each other.

5. 5. The light-emitting element driving circuit according to claim 4, wherein the adjustment output terminal is coupled to the adjustment control terminal of the variable resistor module, and the impedance adjustment branch circuit is configured to adjust the impedance of the variable resistor module according to the voltages on both sides of the driving power supply stage.

6. 6. The light-emitting element driving circuit according to claim 5, wherein the impedance adjustment branch circuit is configured to adjust the impedance of the variable resistor module to increase when the voltage drop of the driving power supply stage is greater than the predetermined compensation voltage value, and / or the impedance adjustment branch circuit is configured to adjust the impedance of the variable resistor module to decrease when the voltage drop of the driving power supply stage is less than the predetermined compensation voltage value.

7. 3. The light-emitting element driving circuit according to claim 2, further comprising a sampling circuit, wherein the error amplification circuit is coupled between the driving power supply stage and the light-emitting element via the compensation circuit and the sampling circuit, the sampling circuit is configured to collect voltage extreme values ​​of nodes between the driving power supply stage and the light-emitting element, and the compensation circuit is configured to compensate for the voltage extreme values ​​according to a compensation voltage having the predetermined compensation voltage value.

8. When the light-emitting device is coupled to a driving input terminal of the driving power supply stage, the sampling circuit is configured to collect a sampling voltage having a minimum voltage value at the driving input terminal, and the compensation circuit is configured to negatively compensate the sampling voltage according to the compensation voltage; 8. The light-emitting element driving circuit according to claim 7, wherein when the light-emitting element is coupled to the driving output terminal of the driving power supply stage, the sampling circuit is configured to collect a sampling voltage having a maximum voltage value at the driving output terminal, and the compensation circuit is configured to positively compensate the sampling voltage according to the compensation voltage.

9. the impedance adjustment module is connected in series between a power supply and a driving input terminal of the driving power supply stage, the light emitting device is connected in series between a driving output terminal of the driving power supply stage and ground, and the compensation circuit includes a first N-type transistor, a first P-type transistor and a compensation resistor; 8. The light-emitting element driving circuit according to claim 7, wherein the gate of the first N-type transistor is coupled to the sampling circuit, the drain is coupled to a power supply, and the source is coupled to the gate of the first P-type transistor, the drain of the first P-type transistor is grounded, and the source is coupled to the error amplifier circuit via the compensation resistor.

10. the impedance adjustment module is connected in series between the driving output terminal of the driving power supply stage and ground, the light emitting device is connected in series between a power supply and the driving input terminal of the driving power supply stage, and the compensation circuit includes a first P-type transistor, a first N-type transistor and a compensation resistor; 8. The light-emitting element driving circuit according to claim 7, wherein the gate of the first P-type transistor is coupled to the sampling circuit, the drain is grounded, and the source is coupled to the gate of the first N-type transistor, the drain of the first N-type transistor is coupled to a power supply, and the source is coupled to the error amplifier circuit via the compensation resistor.

11. the sampling circuit includes an output transistor, a first input transistor, a second input transistor, a first mirroring branch circuit, and a second mirroring branch circuit, the first input transistor and the second input transistor being connected in parallel with each other and in series with the first mirroring branch circuit, and the output transistor being connected in series with the second mirroring branch circuit; 8. The light-emitting element driving circuit according to claim 7, wherein the control end of the first input transistor is connected to a first driving branch circuit of the driving power supply stage, and the control end of the second input transistor is connected to a second driving branch circuit of the driving power supply stage.

12. 2. The light-emitting element driving circuit of claim 1, wherein the light-emitting element driving circuit includes a plurality of light-emitting elements, and at least a first light-emitting branch circuit and a second light-emitting branch circuit connected in parallel to each other are formed; the driving power supply stage includes at least a first driving branch circuit and a second driving branch circuit, the first light-emitting branch circuit is coupled to the first driving branch circuit to form a first channel, and the second light-emitting branch circuit is coupled to the second driving branch circuit to form a second channel, and the first channel and the second channel are connected in parallel.

13. 13. The light-emitting element driving circuit according to claim 12, further comprising a current control circuit and a resistor, the control output terminal of the current control circuit being connected to the first driving branch circuit and the second driving branch circuit respectively, and the resistor being connected in series between the input terminal of the current control circuit and ground.

14. A light-emitting element driving chip, comprising the light-emitting element driving circuit of claim 1, wherein the impedance adjustment module comprises a shunt module and a variable resistor module, the light-emitting element driving chip further comprises a substrate, the variable resistor module, the driving power supply stage and the impedance adjustment branch circuit are disposed on the substrate, the shunt module is disposed outside the substrate, the variable resistor module comprises one or more of a variable resistor and an adjustment transistor, and the shunt module comprises a shunt resistor.

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