CN215898060U - Constant current drive circuit, constant current drive device and lamp - Google Patents
Constant current drive circuit, constant current drive device and lamp Download PDFInfo
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- CN215898060U CN215898060U CN202121753824.8U CN202121753824U CN215898060U CN 215898060 U CN215898060 U CN 215898060U CN 202121753824 U CN202121753824 U CN 202121753824U CN 215898060 U CN215898060 U CN 215898060U
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Abstract
The application is applicable to the technical field of electronics, and provides a constant current driving circuit, a constant current driving device and a lamp, wherein an input voltage sampling signal is generated by collecting the voltage of an input end through a peak voltage sampling and holding module, the holding voltage at the current moment is obtained by averaging the peak voltage of the input voltage sampling signal and the holding voltage at the previous moment, the holding voltage at the current moment is output to a voltage-controlled current source module as an output voltage signal, then a corresponding current signal is generated by the voltage-controlled current source module according to the output voltage signal and a preset second threshold voltage, a constant current threshold control module mirrors the current signal to generate a mirror current signal, and a constant current threshold is adjusted according to the mirror current signal so as to keep the working current flowing out of a load constant, thereby adaptively controlling the constant current threshold when the input voltage fluctuates, effectively reducing the current ripple caused by the fluctuation of the input voltage.
Description
Technical Field
The application belongs to the technical field of electronics, and particularly relates to a constant current driving circuit, a constant current driving device and a lamp.
Background
In a constant current system powered by mains supply, the input voltage of a constant current driving circuit is obtained by subtracting the conduction voltage of an LED lamp string from rectified and filtered mains supply voltage, and when the mains supply voltage fluctuates, the input voltage of the constant current driving circuit is lower than the constant current threshold of the constant current driving circuit, so that ripples appear in current flowing through the LED lamp string, and the problems of flicker, excessive stroboscopic index and the like of the whole LED system are caused.
SUMMERY OF THE UTILITY MODEL
In view of this, the present application provides a constant current driving circuit, a constant current driving device, and a lamp, which can adaptively control a constant current threshold when an input voltage fluctuates, effectively reduce current ripples caused by the fluctuation of the input voltage, and solve the problems of flicker, excessive stroboscopic index, and the like caused when the input voltage of the constant current driving circuit is lower than the constant current threshold of the constant current driving circuit.
The embodiment of the application provides a constant current driving circuit, the constant current driving circuit includes:
the peak voltage sampling and holding module is used for acquiring the voltage of an input end to generate an input voltage sampling signal, obtaining the holding voltage at the current moment according to the peak voltage of the input voltage sampling signal and the average value of the holding voltage at the previous moment, and taking the holding voltage at the current moment as the voltage value of the output voltage signal;
the voltage-controlled current source module is connected with the peak voltage sampling and holding module and used for receiving the output voltage signal and generating a corresponding current signal according to the output voltage signal and a preset second threshold voltage;
and the constant current threshold control module is connected with the voltage-controlled current source module and used for mirroring the current signals according to the proportionality coefficient to generate mirror image current signals and adjusting the constant current threshold according to the mirror image current signals so as to keep the working current flowing through the load constant.
In one embodiment, the peak voltage sample-and-hold module comprises:
the input voltage sampling unit is used for sampling a voltage signal at an input end to generate an input voltage sampling signal;
the single-laser signal generating unit is connected with the input voltage sampling unit and used for generating a first serial single-laser signal and a second serial single-laser signal when the voltage value of the input voltage sampling signal is greater than a first threshold voltage, wherein the second serial single-laser signal is generated after the first serial single-laser signal;
and the sampling voltage averaging unit is connected with the input voltage sampling unit and the single-excitation signal generating unit and is used for acquiring the peak voltage of the input voltage sampling signal, averaging the holding voltage at the last moment with the peak voltage in the first serial single-excitation signal duration period, and updating the holding voltage to the holding voltage at the current moment as the voltage value of the output voltage signal.
In one embodiment, the input voltage sampling unit includes: a first resistor and a second resistor;
the first end of the first resistor is connected with the input end, the second end of the first resistor and the first end of the second resistor are connected to the peak voltage sampling unit in a shared mode, and the second resistor is grounded.
In one embodiment, the single-shot signal generating unit includes: a single-shot signal generator and a first operational amplifier;
the non-inverting input end of the first operational amplifier is connected with the voltage sampling unit, the inverting input end of the first operational amplifier is connected with the first threshold voltage source, the output end of the first operational amplifier is connected with the single-excitation signal amplifier, and the first output end and the second output end of the single-excitation signal are both connected with the sampling voltage averaging unit.
In one embodiment, the sampling voltage averaging unit is further configured to acquire an average voltage of the input voltage sampling signal, update the average voltage of the current input voltage sampling signal to a holding voltage at the current time, or update a peak voltage of the current input voltage sampling signal to the holding voltage at the current time.
In one embodiment, the sampling voltage averaging unit includes: the circuit comprises a second operational amplifier, a first switching tube, a first capacitor, a second switching tube, a third switching tube, a fourth switching tube, a fifth switching tube, a second capacitor and a restorer;
the non-inverting input end of the second operational amplifier and the first end of the first switch tube are connected to the input voltage sampling unit in a shared manner, the inverting input end of the second operational amplifier, the second end of the first switch tube, the first end of the first capacitor, the first end of the second switch tube and the first end of the third switch tube are connected in a shared manner, the second end of the first capacitor is grounded, and the output end of the second operational amplifier, the control end of the first switch tube and the first end of the fourth switch tube are connected in a shared manner;
the control end of the second switch tube is connected with the first output end of the single laser signal generation unit, the second end of the third switch tube is grounded, the control end of the third switch tube is connected with the control end of the fourth switch tube in common with the second output end of the single laser signal generation unit, the second end of the fourth switch tube is grounded, the second end of the second switch tube is connected with the first end of the fifth switch tube in common with the first end of the second capacitor in common with the voltage-controlled current source module, the second end of the second capacitor is grounded, the second end of the fifth switch tube is grounded, and the control end of the fifth switch tube is connected with the restorer.
In one embodiment, the voltage controlled current source module comprises: the third operational amplifier, the fourth operational amplifier, a sixth switching tube and a third resistor;
the first end of the sixth switching tube is connected with the constant current threshold control module, the non-inverting input end of the third operational amplifier is connected with the second threshold voltage source, the inverting input end of the third operational amplifier, the second end of the sixth switching tube and the first end of the third resistor are connected, the control end of the sixth switching tube is connected with the output end of the third operational amplifier, the non-inverting input end of the fourth operational amplifier is connected with the peak voltage sampling and holding module, and the inverting input end of the fourth operational amplifier and the output end of the fourth operational amplifier are connected to the second end of the third resistor in common.
In one embodiment, the constant current threshold control module comprises:
the current mirror unit is connected with the voltage-controlled current source module and used for carrying out mirror amplification on the current signal to generate a mirror current signal;
and the working current adjusting unit is connected with the current mirror image unit and adjusts a constant current threshold according to the mirror image current signal so as to keep the working current flowing out of the load constant.
The embodiment of the application also provides a constant current driving device which comprises the constant current driving circuit in any one of the embodiments.
An embodiment of the present application further provides a lamp, including: a light source load; and the constant current driving circuit according to any one of the above embodiments, wherein the constant current driving circuit is connected to the light source load.
The embodiment of the application provides a constant current drive circuit, constant current drive arrangement and lamps and lanterns, and the constant current drive circuit includes: the peak voltage sampling and holding module is used for collecting the voltage of an input end to generate an input voltage sampling signal, averaging the peak voltage of the input voltage sampling signal and the holding voltage at the previous moment to obtain the holding voltage at the current moment, outputting the holding voltage at the current moment to the voltage-controlled current source module as an output voltage signal, wherein the initial value of the holding voltage is 0, then the voltage-controlled current source module generates a corresponding current signal according to the output voltage signal and a preset second threshold voltage, the constant current threshold control module mirrors the current signal to generate a mirror current signal, and adjusts the constant current threshold according to the mirror current signal to keep the working current flowing out of a load constant, so that the constant current threshold is controlled in a self-adaptive manner when the input voltage fluctuates, effectively reducing the current ripple caused by the fluctuation of the input voltage.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a conventional LED constant current system;
fig. 2 is a schematic structural diagram of a constant current driving circuit provided in an embodiment of the present application;
fig. 3 is a schematic circuit diagram of a constant current driving circuit according to an embodiment of the present application;
fig. 4 is an application schematic diagram of a constant current driving circuit provided in an embodiment of the present application;
FIG. 5 is a schematic diagram of voltage variation provided by an embodiment of the present application;
fig. 6 is an application schematic diagram of another constant current driving circuit provided in the embodiment of the present application.
Detailed Description
In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The terms "comprises" and "comprising," and any variations thereof, in the description and claims of this application and the drawings described above, are intended to cover non-exclusive inclusions. For example, a process, method, or system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus. Furthermore, the terms "first," "second," and "third," etc. are used to distinguish between different objects and are not used to describe a particular order.
In order to solve the above technical problem, an embodiment of the present application provides a constant current driving circuit, as shown in fig. 2, the constant current driving circuit is connected to a load, and the constant current driving circuit includes: a peak voltage sample-and-hold module 10, a voltage controlled current source module 20, and a constant current threshold control module 30.
Specifically, the peak voltage sampling and holding module 10 is configured to collect a voltage at an input end to generate an input voltage sampling signal, average the peak voltage of the input voltage sampling signal and a holding voltage at a previous time to obtain a holding voltage at a current time, and output the holding voltage at the current time as an output voltage signal to the voltage-controlled current source module.
The voltage-controlled current source module 20 is connected to the peak voltage sample-and-hold module 10, and the voltage-controlled current source module 20 is configured to generate a corresponding current signal according to the output voltage signal and a preset second threshold voltage; the constant current threshold control module 30 is connected to the voltage-controlled current source module 20 and the load, and is configured to mirror the current signal, generate a mirror current signal, and adjust the constant current threshold according to the mirror current signal, so that the working current flowing out of the load is kept constant, and thus the constant current threshold is adaptively controlled when the input voltage fluctuates, and current ripples caused by the fluctuation of the input voltage are effectively reduced.
In the embodiment, in order to adaptively adjust the constant current threshold of the constant current driving circuit, firstly, the peak voltage sampling and holding module 10 averages the peak voltage of the input voltage sampling signal and the holding voltage at the previous moment to obtain the holding voltage at the current moment, and outputs the holding voltage at the present moment as an output voltage signal to the voltage-controlled current source module, then the voltage-controlled current source module 20 generates a corresponding current signal according to the output voltage signal and a preset second threshold voltage, the constant current threshold control module 30 mirrors the current signal to generate a mirror current signal, and the constant current threshold value is adjusted according to the mirror current signal so as to keep the working current flowing out of the load constant, therefore, when the input voltage fluctuates, the constant current threshold is controlled in a self-adaptive mode, and current ripples caused by the fluctuation of the input voltage are effectively reduced.
In a specific application embodiment, the input end of the peak voltage sample-and-hold module 10 receives an externally input voltage signal, and the output end thereof is connected to the voltage-controlled current source module 20, and is used for sampling the peak voltage of the currently externally input voltage signal in real time, buffering the voltage at the previous time, obtaining an average value of the peak voltage and the voltage at the previous time, updating the average value to the voltage value at the current time, and outputting the voltage value as an output voltage signal to the voltage-controlled current source module 20.
One end of the voltage-controlled current source module 20 is connected to the peak voltage sample-and-hold module 10, and the other end is connected to the constant current threshold control module 30, so that a corresponding current signal can be obtained through conversion according to an output voltage signal provided by the peak voltage sample-and-hold module 10.
The constant current threshold control module 30 performs mirror amplification on the current signal according to a certain proportionality coefficient K, and adjusts the constant current threshold according to the mirror current signal obtained by mirror amplification, so that the working current flowing out of the load keeps constant.
In one embodiment, referring to fig. 3, the peak voltage sample-and-hold module 10 includes: the input voltage sampling unit 11 is used for sampling a voltage signal at an input end to generate an input voltage sampling signal; the single-laser signal generating unit 12 is connected to the input voltage sampling unit 11, and configured to generate a first serial single-laser signal and a second serial single-laser signal when a voltage value of the input voltage sampling signal is greater than a first threshold voltage, where the second serial single-laser signal is generated after the first serial single-laser signal.
The sampling voltage averaging unit 13 is connected with the input voltage sampling unit 11 and the single-excitation signal generating unit 12, and the sampling voltage averaging unit 13 is used for receiving the input voltage sampling signal and acquiring the peak voltage of the input voltage sampling signal; and storing the voltage value of the input voltage sampling signal at the previous moment according to the first serial single laser signal and the second serial single laser signal, and determining the voltage average value of the input voltage sampling signal and the input voltage sampling signal at the previous moment to generate an output voltage signal.
In this embodiment, the single-stimulus signal generating unit 12 delays to generate two serial single-stimulus signals after power-on, the sampling voltage averaging unit 13 performs charge-discharge adjustment on the acquired voltage signals according to the two serial single-stimulus signals to determine a voltage peak value of the input voltage sampling signal, during the duration of the first serial single-stimulus signal, averages the holding voltage at the previous time with the peak voltage, and updates the averaged voltage to the holding voltage at the current time as the voltage value of the output voltage signal.
In one embodiment, referring to fig. 3, the input voltage sampling unit 11 includes: a first resistor R1 and a second resistor R2; the first end of the first resistor R1 is connected to the input terminal, the second end of the first resistor R1 and the first end of the second resistor R2 are connected to the sampling voltage averaging unit 13, and the second resistor R2 is grounded.
In this embodiment, the first resistor R1 and the second resistor R2 form a voltage divider circuit, which divides the voltage at the input terminal to generate an input voltage sampling signal.
In one embodiment, referring to fig. 3, the single-shot signal generating unit 12 includes: a single-shot signal generator 121 and a first operational amplifier Y1; the non-inverting input end of the first operational amplifier Y1 is connected to the voltage sampling unit, the inverting input end of the first operational amplifier Y1 is connected to the first threshold voltage source, the output end of the first operational amplifier Y1 is connected to the single-shot signal amplifier, and both the first output end and the second output end of the single-shot signal generation are connected to the sampling voltage averaging unit 13.
In a single mains half-wave period, when the voltage of V1 is greater than the voltage Vref1 at the inverting input terminal of the first operational amplifier Y1, the single-shot signal generator 121 will delay to generate two serial single-shot signals, i.e., a first serial single-shot signal CKA and a second serial single-shot signal CKB, where the second serial single-shot signal CKB is generated after the first serial single-shot signal CKA ends for a period of time.
In one embodiment, the sampling voltage averaging unit 13 includes: the circuit comprises a second operational amplifier Y2, a first switch tube M1, a first capacitor C1, a second switch tube M2, a third switch tube M3, a fourth switch tube M4, a fifth switch tube M5, a second capacitor C2 and a restorer 141.
The non-inverting input terminal of the second operational amplifier Y2 and the first terminal of the first switch tube M1 are commonly connected to the input voltage sampling unit 11, the inverting input terminal of the second operational amplifier Y2, the second terminal of the first switch tube M1 and the first terminal of the first capacitor C1 are commonly connected to the first terminal of the second switch tube M2, the second terminal of the first capacitor C1 is grounded, and the output terminal of the second operational amplifier Y2 and the control terminal of the first switch tube M1 are commonly connected to the first terminal of the fourth switch tube.
The control end of the second switching tube M2 is connected to the single-excitation signal generating unit 12, the first end of the second switching tube M2 and the first end of the third switching tube M3 are connected in common, the second end of the third switching tube M3 is grounded, the control end of the third switching tube M3 and the control end of the fourth switching tube M4 are connected in common to the single-excitation signal generating unit 12, the second end of the fourth switching tube M4 is grounded, the second end of the second switching tube M2, the first end of the fifth switching tube M5 and the first end of the second capacitor C2 are connected in common to the voltage-controlled current source module 20, the second end of the second capacitor C2 is grounded, the second end of the fifth switching tube M5 is grounded, and the control end of the fifth switching tube M5 is connected to the reset 141.
In this embodiment, the second operational amplifier Y2, the first switch tube M1, and the first capacitor C1 form a peak voltage sampling circuit, the voltage value of the input voltage sampling signal can be set to V1, the voltage value of the connection end between the first switch tube M1 and the first capacitor C1 is V2, when V2 is smaller than V1, the first switch tube M1 is turned on, and V2 continues to be charged until when the voltage V2 on the first capacitor C1 is greater than or equal to V1, the first switch tube M1 is turned off, the charging circuit of V2 is turned off, and at this time, the voltage V2 is the peak voltage of V1.
In one embodiment, the first switching tube M1, the second switching tube M2, the third switching tube M3, the fourth switching tube M4 and the fifth switching tube M5 are N-type MOS transistors.
The first serial single excitation signal CKA is output to the control end of the second switch tube M2, the second serial single excitation signal CKB is output to the control ends of the third switch tube M3 and the fourth switch tube M4, the second switch tube M2 is turned on by the first serial single excitation signal CKA, at this time, the voltage V2 is averaged with the voltage V4 at the first end of the second capacitor C2, the third switch tube M3 and the fourth switch tube M4 are turned on by the second serial single excitation signal CKB, the voltage V2 is reduced to zero, and the first switch tube M1 is turned off.
In a specific application, the average voltage value after the averaging process is updated to the current-time voltage value as the voltage value of the output voltage signal, and the current-time voltage value is transmitted to the voltage-controlled current source module 20 at the same time, for example, the average value is accumulated and calculated in the form of (((1+0)/2+2)/2) +3)/2 …, and the output voltage signal is output to the voltage-controlled current source module 20, so that the constant current threshold is adaptively controlled when the input voltage fluctuates, and the current ripple caused by the fluctuation of the input voltage is effectively reduced.
In one embodiment, the sampling voltage averaging unit 13 is further configured to acquire an average voltage of the input voltage sampling signal, and update the average voltage of the current input voltage sampling signal to a holding voltage at the current time.
In this embodiment, the sampling voltage averaging unit 13 performs charge and discharge adjustment on the acquired voltage signals according to the two serial single-laser signals to determine an average voltage of the input voltage sampling signals, for example, the first serial single-laser signal CKA controls the second switching tube M2 to be turned on and off, and the second serial single-laser signal CKB controls the third switching tube M3 and the fourth switching tube M4 to be turned on and off, so as to acquire the voltage of the input voltage sampling signals and control the voltage V2 and the voltage V4 averaging process.
Specifically, the second operational amplifier Y2, the first switch tube M1, and the first capacitor C1 form a voltage sampling circuit, the voltage value of the input voltage sampling signal can be set to V1, the voltage value of the connection end between the first switch tube M1 and the first capacitor C1 is V2, when V2 is less than V1, the first switch tube M1 is turned on, and V2 is continuously charged until when the voltage V2 on the first capacitor C1 is greater than or equal to V1, the first switch tube M1 is turned off, the V2 charging circuit is turned off, and at this time, the voltage V2 is the average voltage of V1.
In one embodiment, the sampling voltage averaging unit 13 is further configured to update the peak voltage of the current input voltage sampling signal to the holding voltage at the current time.
In this embodiment, the sampling voltage averaging unit 13 performs charge and discharge adjustment on the collected voltage signals according to two serial single-excited signals, controls the second switching tube M2 to be turned on and off through the first serial single-excited signal CKA, and controls the third switching tube M3 and the fourth switching tube M4 to be turned on and off through the second serial single-excited signal CKB, so as to directly update the peak voltage of the input voltage sampling signal to the holding voltage at the current time.
In one embodiment, the voltage controlled current source module 20 includes: the third operational amplifier Y3, the fourth operational amplifier Y4, the sixth switching tube M6 and the third resistor R3; a first end of a sixth switching tube M6 is connected to the constant current threshold control module 30, a non-inverting input end of a third operational amplifier Y3 is connected to the second threshold voltage source, an inverting input end of the third operational amplifier Y3, a second end of the sixth switching tube M6, and a first end of a third resistor R3 are connected, a control end of a sixth switching tube M6 is connected to an output end of the third operational amplifier Y3, a non-inverting input end of a fourth operational amplifier Y4 is connected to the peak voltage sample-and-hold module 10, and an inverting input end of the fourth operational amplifier Y4 and an output end of the fourth operational amplifier Y4 are connected to a second end of the third resistor R3 in common.
In this embodiment, the third operational amplifier Y3, the fourth operational amplifier Y4, the sixth switching tube M6, and the third resistor R3 constitute a voltage-controlled current source to provide a current signal for the constant current threshold control module 30, wherein the non-inverting input terminal of the third operational amplifier Y3 is connected to the second threshold voltage source, the voltage value of the non-inverting input terminal thereof is Vref2, the non-inverting input terminal of the fourth operational amplifier Y4 is connected to the peak voltage sample-and-hold module 10, and the voltage value thereof is V4, since the resistance value of the third resistor R3 is much larger than the on-resistance of the sixth switching tube M6, the current flowing through the sixth switching tube M6 is I1 (Vref 2-V4)/R3; where Vref2 is the voltage value of the second threshold voltage provided by the second threshold voltage source, and V4 is the voltage value of the output voltage signal generated by the peak voltage sample-and-hold module 10.
In one embodiment, referring to fig. 3, the constant current threshold control module 30 includes: a current mirror unit 31 and an operating current adjusting unit 32; the current mirror unit 31 is connected to the voltage-controlled current source module 20, and is configured to mirror the current signal to generate a mirror current signal; the working current adjusting unit 32 is connected with the current mirror unit 31 and the load, and adjusts the constant current threshold according to the mirror current signal, so that the working current flowing out of the load is kept constant.
In this embodiment, referring to fig. 3, the seventh switching tube M7 and the eighth switching tube M8 form a current mirror circuit, and the current flowing through the eighth switching tube M8 is I2 ═ K × I1, where the size of the proportionality coefficient K is determined by the size ratio of the seventh switching tube M7 and the eighth switching tube M8.
In one embodiment, referring to fig. 3, the operating current adjusting unit 32 includes: a fifth operational amplifier Y5, a ninth switch tube M9, a fourth resistor R4 and a fifth resistor R5.
Specifically, the non-inverting input terminal of the fifth operational amplifier Y5 is connected to the second threshold voltage source, the inverting input terminal of the fifth operational amplifier Y5 and the first terminal of the fourth resistor R4 are connected to the current mirror unit 31 in common, the output terminal of the fifth operational amplifier Y5 is connected to the control terminal of the ninth switching tube M9, the first terminal DRAIN of the ninth switching tube M9 is connected to the load, the second terminal of the ninth switching tube M9, the second terminal of the fourth resistor R4 and the first terminal of the fifth resistor R5 are connected in common, and the second terminal of the fifth resistor R5 is connected to the ground.
In one embodiment, the ninth switch transistor M9 is an N-type MOS transistor.
In this embodiment, the fourth resistor R4 is connected in series with the eighth switching tube M8, and the current flowing through the fourth resistor R4 is also I2, so the voltage at the common junction of the second end of the ninth switching tube M9, the second end of the fourth resistor R4, and the first end of the fifth resistor R5 is V5 — Vref2-I2 — R4, and therefore, the current flowing through the load and the ninth switching tube M9 is:
fig. 4 is an application schematic diagram of the constant current driving circuit applied to an LED constant current system, and referring to fig. 4, the load is an LED lamp string, a first end of a ninth switching tube M9 is connected to a current output end of the LED lamp string, an input end of the peak voltage sample-and-hold module 10 is connected to an output end of a rectifier bridge DB, and a direct current output by the rectifier bridge DB is processed by a first diode D1 and a third capacitor C3 and then output to the LED lamp string.
Fig. 5 shows a schematic diagram of voltage changes of several cycles V1, V2, V4, and V5, and with reference to fig. 4 and 5, in the power-up initial state, the voltage of V4 is zero, and after several cycles, V4 reaches the voltage of V2, that is, reaches the peak voltage of V1, and when the voltage of the utility power decreases, the peak voltage of V1 decreases, which results in a decrease in the voltage of V4, so that the current flowing through the LED and the ninth switch tube M9 decreases, and since the current flowing through the ninth switch tube M9 decreases, the constant current threshold of the ninth switch tube M9 also decreases, so that the current flowing through the load can still keep constant.
Referring to fig. 6, by adding a thyristor dimmer 40 between the rectifier bridge and the mains supply AC, and controlling the constant current threshold according to the input voltage after the thyristor dimmer 40 phase-cut, it can be ensured that the LED string current ripple is small when the thyristor phase-cut reaches a small angle, and the LED flicker caused by the large and small phase-cut waves of the thyristor itself is optimized.
The embodiment of the application also provides a constant current driving device which comprises the constant current driving circuit in any one of the embodiments.
An embodiment of the present application further provides a lamp, including: a light source load; and the constant current driving circuit according to any one of the above embodiments, wherein the constant current driving circuit is connected to the light source load.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working processes of the units and modules in the system may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.
Claims (10)
1. A constant current drive circuit, characterized in that the constant current drive circuit comprises:
the peak voltage sampling and holding module is used for acquiring the voltage of an input end to generate an input voltage sampling signal, obtaining the holding voltage at the current moment according to the peak voltage of the input voltage sampling signal and the average value of the holding voltage at the previous moment, and taking the holding voltage at the current moment as the voltage value of the output voltage signal;
the voltage-controlled current source module is connected with the peak voltage sampling and holding module and used for receiving the output voltage signal and generating a corresponding current signal according to the output voltage signal and a preset second threshold voltage;
and the constant current threshold control module is connected with the voltage-controlled current source module and used for mirroring the current signals according to the proportionality coefficient to generate mirror image current signals and adjusting the constant current threshold according to the mirror image current signals so as to keep the working current flowing through the load constant.
2. The constant current drive circuit according to claim 1, wherein the peak voltage sample-and-hold module includes:
the input voltage sampling unit is used for sampling a voltage signal at an input end to generate an input voltage sampling signal;
the single-laser signal generating unit is connected with the input voltage sampling unit and used for generating a first serial single-laser signal and a second serial single-laser signal when the voltage value of the input voltage sampling signal is greater than a first threshold voltage, wherein the second serial single-laser signal is generated after the first serial single-laser signal;
and the sampling voltage averaging unit is connected with the input voltage sampling unit and the single-excitation signal generating unit and is used for acquiring the peak voltage of the input voltage sampling signal, averaging the holding voltage at the previous moment with the peak voltage in the first serial single-excitation signal duration, and updating the averaged voltage into the holding voltage at the current moment as the voltage value of the output voltage signal.
3. The constant current drive circuit according to claim 2, wherein the input voltage sampling unit includes: a first resistor and a second resistor;
the first end of the first resistor is connected with the input end, the second end of the first resistor and the first end of the second resistor are connected to the peak voltage sampling unit in a shared mode, and the second resistor is grounded.
4. The constant current drive circuit according to claim 2, wherein the one shot signal generating unit includes: a single-shot signal generator and a first operational amplifier;
the non-inverting input end of the first operational amplifier is connected with the voltage sampling unit, the inverting input end of the first operational amplifier is connected with the first threshold voltage source, the output end of the first operational amplifier is connected with the single-excitation signal amplifier, and the first output end and the second output end of the single-excitation signal generator are connected with the sampling voltage averaging unit.
5. The constant current driving circuit according to claim 2, wherein the sampling voltage averaging unit is further configured to acquire an average voltage of the input voltage sampling signal, update the average voltage of the current input voltage sampling signal to a holding voltage at the current time, or update a peak voltage of the current input voltage sampling signal to a holding voltage at the current time.
6. The constant current drive circuit according to claim 2, wherein the sampling voltage averaging unit includes: the circuit comprises a second operational amplifier, a first switching tube, a first capacitor, a second switching tube, a third switching tube, a fourth switching tube, a fifth switching tube, a second capacitor and a restorer;
the non-inverting input end of the second operational amplifier and the first end of the first switch tube are connected to the input voltage sampling unit in a shared manner, the inverting input end of the second operational amplifier, the second end of the first switch tube, the first end of the first capacitor, the first end of the second switch tube and the first end of the third switch tube are connected in a shared manner, the second end of the first capacitor is grounded, and the output end of the second operational amplifier, the control end of the first switch tube and the first end of the fourth switch tube are connected in a shared manner;
the control end of the second switch tube is connected with the first output end of the single laser signal generation unit, the second end of the third switch tube is grounded, the control end of the third switch tube is connected with the control end of the fourth switch tube in common with the second output end of the single laser signal generation unit, the second end of the fourth switch tube is grounded, the second end of the second switch tube is connected with the first end of the fifth switch tube in common with the first end of the second capacitor in common with the voltage-controlled current source module, the second end of the second capacitor is grounded, the second end of the fifth switch tube is grounded, and the control end of the fifth switch tube is connected with the restorer.
7. The constant current drive circuit of claim 1, wherein the voltage controlled current source module comprises: the third operational amplifier, the fourth operational amplifier, a sixth switching tube and a third resistor;
the first end of the sixth switching tube is connected with the constant current threshold control module, the non-inverting input end of the third operational amplifier is connected with the second threshold voltage source, the inverting input end of the third operational amplifier, the second end of the sixth switching tube and the first end of the third resistor are connected, the control end of the sixth switching tube is connected with the output end of the third operational amplifier, the non-inverting input end of the fourth operational amplifier is connected with the peak voltage sampling and holding module, and the inverting input end of the fourth operational amplifier and the output end of the fourth operational amplifier are connected to the second end of the third resistor in common.
8. The constant current drive circuit according to claim 1, wherein the constant current threshold control module includes:
the current mirror unit is connected with the voltage-controlled current source module and used for carrying out mirror amplification on the current signal to generate a mirror current signal;
and the working current adjusting unit is connected with the current mirror image unit and adjusts a constant current threshold according to the mirror image current signal so as to keep the working current flowing through the load constant.
9. A constant current driving device characterized by comprising the constant current driving circuit according to any one of claims 1 to 8.
10. A light fixture, comprising: a light source load; and the constant current drive circuit according to any one of claims 1 to 8, which is connected to the light source load.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121753824.8U CN215898060U (en) | 2021-07-29 | 2021-07-29 | Constant current drive circuit, constant current drive device and lamp |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121753824.8U CN215898060U (en) | 2021-07-29 | 2021-07-29 | Constant current drive circuit, constant current drive device and lamp |
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| Publication Number | Publication Date |
|---|---|
| CN215898060U true CN215898060U (en) | 2022-02-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121753824.8U Active CN215898060U (en) | 2021-07-29 | 2021-07-29 | Constant current drive circuit, constant current drive device and lamp |
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| Country | Link |
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| CN (1) | CN215898060U (en) |
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2021
- 2021-07-29 CN CN202121753824.8U patent/CN215898060U/en active Active
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