Reference voltage generating circuit, LED driving circuit and LED solar simulator
Through the reference voltage generation circuit and the LED driving circuit, the LED brightness is adjusted in real time, which solves the problems of slow LED brightness adjustment speed and low consistency in the prior art, and achieves efficient and unified LED brightness control.
Patent Information
- Application Number
- CN202422370223.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2025-07-22
- Estimated Expiration
- 2034-09-27
AI Technical Summary
In the prior art, the display control of multiple LEDs achieves brightness adjustment by adjusting the operating current of the drive LED, the adjustment speed is slow, the resource occupancy is high, and the consistency of the output control signal is not high.
The reference voltage generation circuit is adopted to adjust the brightness of the LED in real time through the signal input circuit and the PID calculation circuit, and combine the LED driving circuit and the digital-to-analog conversion circuit to achieve real-time and reliable control of the brightness of the LED.
It improves the control efficiency of LED brightness, ensures consistency of LED display, reduces system resource usage, and achieves rapid response brightness adjustment.
Smart Images
Figure CN223142169U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of LED solar simulators, and particularly to a reference voltage generation circuit, an LED driving circuit, and an LED solar simulator. Background Art
[0002] A solar simulator is a simulator that provides an accurate and reliable light source for lighting research in a laboratory environment by simulating the spectrum, radiation intensity, and angular distribution of sunlight in applications such as optoelectronic device testing. Due to the low power consumption of LEDs, a solar simulator composed of multiple strings of LEDs with different spectra can operate in a constant-on state, and the LED solar simulator is a light source widely used in the testing of solar cells and modules.
[0003] For the display control of multiple LEDs, the working current of the driving LEDs can be adjusted by configuring a digital-to-analog conversion chip and continuously refreshing the configuration of the digital-to-analog conversion chip synchronously to achieve the adjustment of the LED brightness. However, the working current adjustment speed of this method is slow, the resource occupancy rate is high, and the consistency of the output control signal is not high. Summary of the Utility Model
[0004] Based on this, it is necessary to provide a reference voltage generation circuit, an LED driving circuit, and an LED solar simulator, which can adjust the brightness of the LEDs in the LED solar simulator in real time by changing the reference voltage, and have good consistency.
[0005] In a first aspect, the present disclosure provides a reference voltage generation circuit, including:
[0006] A signal input circuit, which includes a first input circuit and a second input circuit. The first input circuit is used to receive a feedback light intensity signal and output a first input signal according to the feedback light intensity signal; the second input circuit is used to receive a target light intensity signal and output a second input signal according to the target light intensity signal; the signal input circuit is used to obtain a target input signal according to the first input signal and the second input signal;
[0007] A PID operation circuit, connected to the signal input circuit, for performing a PID operation according to the target input signal and outputting a reference voltage.
[0008] In some embodiments, the first input circuit includes a first operational amplifier, and the first operational amplifier includes a first non-inverting input terminal, a first inverting input terminal, and a first output terminal, where:
[0009] The first non-inverting input terminal is used to receive the feedback light intensity signal, and the first output terminal is used to be connected to the PID operation circuit; a first feedback resistor is connected in series between the first non-inverting input terminal and the first output terminal; the first inverting input terminal is used to be grounded.
[0010] In some of these embodiments, the second input circuit includes a second operational amplifier, which includes a second non-inverting input terminal, a second inverting input terminal, and a second output terminal, where:
[0011] The second inverting input terminal is used to receive the target light intensity signal, and the second output terminal is used to connect to the PID operation circuit; a second feedback resistor is connected in series between the second inverting input terminal and the second output terminal; the second non-inverting input terminal is used to be grounded.
[0012] In some of these embodiments, the PID operation circuit includes a third operational amplifier, which includes a third non-inverting input terminal, a third inverting input terminal, and a third output terminal, where:
[0013] The third inverting input terminal is connected to the signal input circuit, and the third output terminal is used to output a reference voltage; a PID circuit is connected between the third inverting input terminal and the third output terminal; the third non-inverting input terminal is used to be grounded.
[0014] In some of these embodiments, the PID circuit includes a first capacitor and a first resistor connected in series, and a second capacitor connected in parallel with the first capacitor and the first resistor.
[0015] In some of these embodiments, the circuit further includes a clamping circuit, one end of the clamping circuit is connected to the signal input circuit, and the other end of the clamping circuit is connected to the PID operation circuit; the clamping circuit is used to clamp the target input signal output by the signal input circuit to obtain a clamped target input signal.
[0016] In some of these embodiments, the circuit further includes a second filtering circuit, one end of the second filtering circuit is used to be connected to the signal input circuit, and the other end of the second filtering circuit is connected to the PID operation circuit; the second filtering circuit is used to filter the target input signal output by the signal input circuit to obtain a filtered target input signal.
[0017] In a second aspect, the present disclosure provides an LED driving circuit, which includes: a control circuit, a digital-to-analog conversion circuit, and a reference voltage generation circuit as described above; the control circuit is respectively connected to the digital-to-analog conversion circuit and the reference voltage generation circuit, and the reference voltage generation circuit is further connected to the digital-to-analog conversion circuit; where:
[0018] The control circuit is used to receive the target light intensity signal and send the target light intensity signal to the reference voltage generation circuit, and the control circuit is further used to configure the preset relationship between the reference voltage and the output current in the digital-to-analog conversion circuit;
[0019] The reference voltage generation circuit is used to receive the feedback light intensity signal and the target light intensity signal, generate a reference voltage according to the target light intensity signal and the feedback light intensity signal, and send the reference voltage to the digital-to-analog conversion circuit;
[0020] The digital-to-analog conversion circuit is used to receive a reference voltage and determine a target current output to the LED driving chip according to a configured preset relationship.
[0021] In some embodiments, the digital-to-analog conversion circuit includes a plurality of digital-to-analog converters connected in series; each digital-to-analog converter is connected to the LED driving chip.
[0022] In a third aspect, the present disclosure provides an LED solar simulator, including the LED driving circuit provided in the second aspect above.
[0023] The above reference voltage generation circuit includes a signal input circuit and a PID operation circuit. Among them, the signal input circuit includes a first input circuit and a second input circuit. The first input circuit is used to receive a feedback light intensity signal and output a first input signal according to the feedback light intensity signal; the second input circuit is used to receive a target light intensity signal and output a second input signal according to the target light intensity signal; the signal input circuit is used to obtain a target input signal according to the first input signal and the second input signal. The PID operation circuit is connected to the signal input circuit and is used to perform a PID operation according to the target input signal and output a reference voltage, and can adjust the reference voltage in real time based on the feedback light intensity signal. Applying the above reference voltage generation circuit to the LED driving circuit, the control circuit inputs the target light intensity signal into the above reference voltage generation circuit, and when driving the LED, inputs the reference voltage generated by the reference voltage generation circuit into the digital-to-analog conversion circuit, and determines the target current output to the LED driving chip according to the configured preset relationship, realizing the control of the LED brightness, improving the control efficiency of the LED brightness, and ensuring the consistency of the LED display. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0025] Figure 1 It is a schematic structural diagram of a reference voltage generation circuit according to an embodiment;
[0026] Figure 2 It is a schematic structural diagram of a reference voltage generation circuit according to another embodiment;
[0027] Figure 3 It is a schematic structural diagram of a reference voltage generation circuit according to another embodiment;
[0028] Figure 4Circuit diagram of a reference voltage generation circuit for an embodiment;
[0029] Figure 5 Structural schematic diagram of an LED driving circuit for an embodiment;
[0030] Figure 6 Circuit diagram of a digital-to-analog conversion circuit for an embodiment. Detailed implementation manners
[0031] For ease of understanding this application, the following will describe this application more comprehensively with reference to relevant accompanying drawings. Embodiments of this application are given in the accompanying drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of this application more thorough and comprehensive.
[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the description of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application.
[0033] It can be understood that the terms "first", "second", etc. used in this application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, the first resistor can be called the second resistor, and similarly, the second resistor can be called the first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.
[0034] It can be understood that "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if there is an electrical signal or data transfer between the connected circuits, modules, units, etc.
[0035] It can be understood that "at least one" means one or more, and "a plurality" means two or more. "At least a part of an element" means a part or all of the element.
[0036] As used herein, the singular forms "a", "an", and "the" may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "comprise / include" or "have" etc. specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the related listed items.
[0037] Currently, for the display control of multiple LEDs, it is achieved by adjusting the operating current of the driven LEDs. For example, by adjusting the magnitude of the current output to the IADJ pin of the LED driver chip, the brightness of the LEDs can be adjusted. However, the traditional adjustment method requires continuously updating the registers of the digital-to-analog converter output to the LED driver chip to achieve the output control of the operating current of each LED, and thus achieve the adjustment of the LED brightness. The adjustment efficiency is low, the system occupancy is large, and the consistency of LED display is not high either.
[0038] In the traditional technology, the reference voltage of the digital-to-analog converter is a fixed value. In this application, the brightness of the LEDs is adjusted by adjusting the reference voltage. Only one parameter configuration is required, which improves the control efficiency of the LED brightness and ensures the consistency of LED display.
[0039] Please refer to Figure 1 the schematic structural diagram of the reference voltage generation circuit. In some embodiments, a reference voltage generation circuit includes a signal input circuit and a PID operation circuit 300 connected to each other. Among them, the signal input circuit includes a first input circuit 100 and a second input circuit 200. The first input circuit 100 is used to receive the feedback light intensity signal and output a first input signal according to the feedback light intensity signal. The second input circuit 200 is used to receive the target light intensity signal and output a second input signal according to the target light intensity signal. The signal input circuit combines the first input signal output by the first input circuit 100 and the second input signal output by the second input circuit 200 to obtain a target input signal. The PID operation circuit 300 performs a PID operation on the target input signal output by the signal input circuit and outputs a reference voltage at the output end of the PID operation circuit 300.
[0040] In some other embodiments, please refer to Figure 2 the schematic structural diagram of the reference voltage generation circuit. The reference voltage generation circuit further includes a clamping circuit 400. As Figure 2 shown, one end of the clamping circuit 400 is connected to the signal input circuit, and the other end is connected to the PID operation circuit 300. The clamping circuit 400 is used to clamp the target input signal output by the signal input circuit to obtain a clamped target input signal.
[0041] Exemplarily, as Figure 4 shown, the clamping circuit 400 may include diodes D1 and D2. The cut-off end of diode D1 and the conducting end of diode D2 are connected to the signal input circuit, and the conducting end of diode D1 and the cut-off end of diode D2 are grounded. The clamping circuit 400 clamps the signals output by the first input circuit 100 and the second input circuit 200 within a very small range after superimposing them through diodes D1 and D2. This voltage range can be related to the forward conduction voltage range of diodes D1 and D2.
[0042] In some further embodiments, referring to Figure 3 the structural schematic diagram of the reference voltage generation circuit of
[0043] It can be understood that the filter circuit 500 can be directly connected to the signal input circuit or indirectly connected to the signal input circuit through the clamping circuit 400. Similarly, the filter circuit 500 can also be directly connected to the PID operation circuit 300 to input the filtered signal into the PID operation circuit 300. It is also possible to first filter the target input signal, then clamp the filtered signal, and finally input the clamped signal into the PID operation circuit 300.
[0044] Still taking the Figure 4 shown reference voltage generation circuit diagram as an example, the filter circuit 500 is arranged between the clamping circuit 400 and the PID operation circuit 300 and is used to filter the clamped target input signal. Exemplarily, the filter circuit 500 is an RC filter. It should be noted that the above filter circuit 500 can also adopt other forms, not limited to the forms already mentioned in the above embodiments, as long as it can achieve the function of signal filtering.
[0045] Please refer to Figure 4 the circuit diagram of the reference voltage generation circuit shown. As Figure 4 shown, in some embodiments, the first input circuit 100 includes a first operational amplifier U1A. The first operational amplifier U1A includes a first non-inverting input terminal, a first inverting input terminal, and a first output terminal. As Figure 4 shown, the first non-inverting input terminal is connected to one end of a resistor R3, and the other end of the resistor R3 is used to receive the feedback light intensity signal. The first output terminal is connected to the PID operation circuit 300 to output a first input signal to the PID operation circuit 300. A first feedback resistor is connected in series between the first non-inverting input terminal and the first output terminal. The first inverting input terminal is grounded.
[0046] In this embodiment, the first input circuit 100 is a non-inverting amplifier circuit, and the output first input signal is related to the feedback light intensity signal, and the signal directions are the same.
[0047] In some other embodiments, please continue to refer to Figure 4, the second input circuit 200 includes a second operational amplifier U1B. The second operational amplifier U1B includes a second non-inverting input terminal, a second inverting input terminal, and a second output terminal. As Figure 4 shown, the second inverting input terminal is connected to one end of a resistor R9, and the other end of the resistor R9 is used to receive a target light intensity signal. The second output terminal is connected to the PID operation circuit 300 for outputting a second input signal to the PID operation circuit 300. A second feedback resistor R7 is connected in series between the second inverting input terminal and the second output terminal; the second non-inverting input terminal is used to be grounded.
[0048] In this embodiment, the second input circuit 200 is an inverting amplifier circuit, and the output second input signal is related to the target light intensity signal with the signal direction opposite.
[0049] The signal input circuit combines the first input signal output by the first input circuit 100 and the second input signal output by the second input circuit 200 for performing PID operation in the PID operation circuit. Since the first input circuit 100 of this embodiment is a non-inverting amplifier and the second input circuit 200 is an inverting amplifier, when the amplification ratios of the first operational amplifier U1A and the second operational amplifier U1B are the same, the target input signal is the difference between the first input signal and the second input signal, that is, the target input signal can be obtained by subtracting the second input signal from the first input signal.
[0050] In some other embodiments, please continue to refer to Figure 4 , the PID operation circuit 300 includes a third operational amplifier U2A. The third operational amplifier includes a third non-inverting input terminal, a third inverting input terminal, and a third output terminal. As Figure 4 shown, the third inverting input terminal is connected to both the first input circuit 100 and the second input circuit 200 for receiving the target input signal after the first input signal and the second input signal are superimposed. The third output terminal is used to output a reference voltage. A PID circuit is connected between the third inverting input terminal and the third output terminal to improve the reliability of the signal output by the PID operation circuit 300. The third non-inverting input terminal is used to be grounded.
[0051] In some specific embodiments, still taking Figure 4 as an example, the PID circuit includes a first capacitor C1 and a first resistor R5 connected in series, and a second capacitor C2 connected in parallel with the capacitor C1 and the resistor R5. The reference voltage output by the PID operation circuit 300 will fluctuate slightly within a certain range, and the PID operation circuit 300 adjusts the amplitude of the output reference voltage according to the capacitors C1, C2 and the resistor R5 in the PID circuit.
[0052] In this embodiment, the first input circuit 100 and the second input circuit 200 respectively receive the feedback light intensity signal and the target light intensity signal, and output a reference voltage. This embodiment can adjust the reference voltage in real time according to the feedback light intensity signal, and reliably and accurately control the LED brightness in real time.
[0053] Please refer to Figure 5 the structural schematic diagram of the LED driving circuit shown in the figure. In some embodiments, the LED driving circuit includes: a control circuit, a digital-to-analog conversion circuit, and the reference voltage generation circuit proposed above. The control circuit is respectively connected to the digital-to-analog conversion circuit and the reference voltage generation circuit, and the reference voltage generation circuit is also connected to the digital-to-analog conversion circuit. As Figure 5 shown in the figure, the control circuit receives the target light intensity signal and sends the target light intensity signal to the reference voltage generation circuit. In addition, the control circuit is also used to configure the preset relationship between the reference voltage and the output current in the digital-to-analog conversion circuit, so as to determine the magnitude of the output current according to different reference voltages.
[0054] During operation, the reference voltage generation circuit directly receives the feedback light intensity signal, generates a reference voltage according to the target light intensity signal and the feedback light intensity signal sent by the control circuit, and sends the reference voltage to the digital-to-analog conversion circuit. After receiving the reference voltage, the digital-to-analog conversion circuit determines the target current output to the LED driving chip according to the configured preset relationship, so as to drive the LED through the target current.
[0055] Exemplarily, the control circuit can be an MCU controller. The control circuit of this embodiment configures the digital-to-analog conversion circuit during initialization, and updates and controls the output current of each LED in real time according to the received reference voltage, so as to realize the adjustment of the LED brightness. Compared with the traditional LED brightness adjustment method, this embodiment improves the control efficiency of the LED brightness and ensures the consistency of the LED display.
[0056] Please refer to Figure 6 In some other embodiments, the digital-to-analog conversion circuit in the LED driving circuit may include multiple digital-to-analog converters. Each digital-to-analog converter is connected in series; each digital-to-analog converter is connected to the LED driving chip.
[0057] Taking the DAC128S085 digital-to-analog converter as an example, each DAC128S085 includes eight output signals. When the number of LEDs is large, multiple signals need to be output to the LED driving chip. Therefore, as Figure 6As shown, multiple digital-to-analog converters are connected in series, and each digital-to-analog converter is connected to an LED driver chip. In the register of each digital-to-analog converter, the relationship between the reference voltage and the output signal is preset to achieve the brightness control of multiple LEDs. In this embodiment, only the relationship between the reference voltage and the output signal in the digital-to-analog conversion circuit needs to be configured through the interface when it is turned on for the first time, and then only the magnitude of the reference voltage needs to be adjusted to achieve the overall synchronous adjustment of the output signal, ensuring the consistency when the LED brightness changes.
[0058] The above LED driver circuit can be applied to an LED solar simulator. In some embodiments, when testing in an environment that needs to simulate sunlight, the above-mentioned LED driver circuit is applied to the LED solar simulator. When the LED solar simulator needs to provide a light source with a stable brightness, the LED solar simulator is driven by the LED driver circuit proposed in the foregoing embodiment, improving the consistency and adjustment efficiency of the brightness adjustment of the LED solar simulator.
[0059] In the description of this specification, the description with reference to terms such as "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.
[0060] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.
[0061] The above-described embodiments only represent several implementation manners of the present application, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.
Claims
1. A reference voltage generation circuit, characterized in that Comprising: A signal input circuit, the signal input circuit includes a first input circuit and a second input circuit. The first input circuit is used to receive a feedback light intensity signal and output a first input signal according to the feedback light intensity signal; the second input circuit is used to receive a target light intensity signal and output a second input signal according to the target light intensity signal; the signal input circuit is used to obtain a target input signal according to the first input signal and the second input signal; A PID operation circuit, connected to the signal input circuit, for performing PID operation according to the target input signal and outputting a reference voltage.
2. The reference voltage generation circuit according to claim 1, wherein The first input circuit includes a first operational amplifier, the first operational amplifier includes a first non-inverting input terminal, a first inverting input terminal and a first output terminal, wherein: The first non-inverting input terminal is used to receive the feedback light intensity signal, and the first output terminal is used to be connected to the PID operation circuit; a first feedback resistor is connected in series between the first non-inverting input terminal and the first output terminal; the first inverting input terminal is used to be grounded.
3. The reference voltage generation circuit according to claim 1, wherein The second input circuit includes a second operational amplifier, the second operational amplifier includes a second non-inverting input terminal, a second inverting input terminal and a second output terminal, wherein: The second inverting input terminal is used to receive the target light intensity signal, and the second output terminal is used to be connected to the PID operation circuit; a second feedback resistor is connected in series between the second inverting input terminal and the second output terminal; the second non-inverting input terminal is used to be grounded.
4. The reference voltage generation circuit according to claim 1, wherein The PID operation circuit includes a third operational amplifier, the third operational amplifier includes a third non-inverting input terminal, a third inverting input terminal and a third output terminal, wherein: The third inverting input terminal is connected to the signal input circuit, and the third output terminal is used to output the reference voltage; a PID circuit is connected between the third inverting input terminal and the third output terminal; the third non-inverting input terminal is used to be grounded.
5. The reference voltage generation circuit according to claim 4, wherein The PID circuit includes a first capacitor and a first resistor connected in series, and a second capacitor connected in parallel with the first capacitor and the first resistor.
6. The reference voltage generation circuit according to claim 1, wherein The circuit further includes a clamping circuit, one end of the clamping circuit is connected to the signal input circuit, and the other end of the clamping circuit is connected to the PID operation circuit; the clamping circuit is used to clamp the target input signal output by the signal input circuit to obtain a clamped target input signal.
7. The reference voltage generation circuit according to claim 1, wherein The circuit further includes a filtering circuit, one end of the filtering circuit is used to be connected to the signal input circuit, and the other end of the filtering circuit is connected to the PID operation circuit; the filtering circuit is used to filter the target input signal to obtain a filtered target input signal.
8. An LED driving circuit, characterized in that, The LED driving circuit includes: a control circuit, a digital-to-analog conversion circuit, and a reference voltage generation circuit according to any one of claims 1-7; the control circuit is respectively connected to the digital-to-analog conversion circuit and the reference voltage generation circuit, and the reference voltage generation circuit is further connected to the digital-to-analog conversion circuit; wherein: The control circuit is configured to receive a target light intensity signal and send the target light intensity signal to the reference voltage generation circuit. The control circuit is further configured to configure a preset relationship between the reference voltage and the output current in the digital-to-analog conversion circuit; The reference voltage generation circuit is configured to receive a feedback light intensity signal and the target light intensity signal, generate a reference voltage according to the target light intensity signal and the feedback light intensity signal, and send the reference voltage to the digital-to-analog conversion circuit; The digital-to-analog conversion circuit is configured to receive the reference voltage and determine a target current output to the LED driver chip according to the configured preset relationship.
9. The LED driving circuit according to claim 8, wherein The digital-to-analog conversion circuit includes a plurality of digital-to-analog converters, and the digital-to-analog converters are connected in series; each digital-to-analog converter is connected to the LED driver chip.
10. An LED solar simulator, characterized in that, An LED driving circuit according to any one of claims 8-9 is included.