LED drive circuit with independently controllable illumination and visible light communication
阅读说明：本技术 一种照明和可见光通信可独立控制的led驱动电路 (LED drive circuit with independently controllable illumination and visible light communication ) 是由 鲍建宇 于 2020-05-28 设计创作，主要内容包括：本发明公开了一种照明和可见光通信可独立控制的LED驱动电路,包括：直流供电电源；电流型BUCK电路,用于将电压源的直流供电电源转换成电流幅值可控可调的直流电流源；并接MOSFET调光电路,在MCU主控电路的控制下实现照明调光用LED阵列的PWM调光；照明调光用LED阵列；光通信调制MOSFET电路,用于在光耦隔离驱动电路控制下实现传输信号的高速调制功能；光通信调制用LED阵列；MCU主控电路,对电流型BUCK电路电流采集,获取外部给定信号,并通过PWM发生器产生对并接MOSFET调光电路控制的脉宽调制PWM控制信号,并获取需传输的高速VPPM信号输出；光耦隔离驱动电路,连接MCU主控电路。(The invention discloses an LED drive circuit capable of independently controlling illumination and visible light communication, which comprises: a DC power supply; the current type BUCK circuit is used for converting a direct current power supply of a voltage source into a direct current source with controllable and adjustable current amplitude; the LED dimming circuit is connected in parallel, and the PWM dimming of the LED array for lighting dimming is realized under the control of the MCU main control circuit; an LED array for lighting and dimming; the optical communication modulation MOSFET circuit is used for realizing the high-speed modulation function of a transmission signal under the control of the optical coupling isolation driving circuit; an LED array for optical communication modulation; the MCU master control circuit is used for collecting the current of the current type BUCK circuit, acquiring an external given signal, generating a Pulse Width Modulation (PWM) control signal controlled by the parallel MOSFET dimming circuit through the PWM generator, and acquiring a high-speed VPPM signal to be transmitted for output; and the optical coupling isolation driving circuit is connected with the MCU main control circuit.)
1. An LED driver circuit with independent control of lighting and visible light communication, comprising:
the direct current power supply is used for providing power for the circuit;
the current type BUCK circuit is used for converting the direct current power supply of the voltage source into a direct current source with controllable and adjustable current amplitude so as to drive a rear-stage LED array for illumination dimming or an LED array for optical communication modulation and complete corresponding current sampling;
the parallel MOSFET dimming circuit is connected with the current type BUCK circuit, is connected to two ends of the LED array for lighting and dimming in parallel and is used for realizing the PWM dimming function of the LED array for lighting and dimming under the control of the MCU main control circuit;
the LED array for lighting dimming comprises a plurality of lighting LED lamps so as to carry out PWM dimming according to the parallel MOSFET dimming circuit;
the optical communication modulation MOSFET circuit is connected with the current type BUCK circuit, is connected to two ends of the LED array for optical communication in parallel, and is used for realizing the high-speed modulation function of a transmission signal under the output control of the optical coupling isolation driving circuit;
the LED array for optical communication modulation comprises a plurality of optical communication LED lamps so as to realize visible light communication based on an LED light source according to the optical communication modulation MOSFET circuit;
the MCU master control circuit is used for collecting current of the current type BUCK circuit, acquiring an external given signal, generating a Pulse Width Modulation (PWM) control signal for controlling the parallel MOSFET dimming circuit through a PWM generator, and acquiring a high-speed VPPM signal to be transmitted and outputting the high-speed VPPM signal to the optical coupling isolation driving circuit;
and the optical coupling isolation driving circuit is used for receiving and processing the high-speed VPPM signal sent by the MCU main control circuit, and outputting a communication control signal to the optical communication modulation MOSFET circuit after optical coupling isolation and high-speed driving processing.
2. An LED driver circuit as claimed in claim 1, wherein the LED driver circuit is configured to control the LED driver circuit independently of the visible light communication, and further comprises: the current type BUCK circuit comprises a first switch diode (D1), a second switch diode (D2), a first free wheel diode (D3), a second free wheel diode (D4), a first rectification control switch tube (S1), a second rectification control switch tube (S2), a first filter inductor (L1), a second filter inductor (L2), a first current sampling device (Det1) and a second current sampling device (Det2), wherein the positive end of the direct current power supply is connected to the anodes of the first switch diode (D1) and the second switch diode (D2), the cathode of the first switch diode (D1) is connected to the drain of the first rectification control switch tube (S1), the source and the substrate of the first rectification control switch tube (S1) are connected with one end of the first filter inductor (L1) and the cathode of the first free wheel diode (D3), and the cathode of the second switch diode (D2) is connected to the second rectification control switch tube (S2), the other end of the first filter inductor (L1) is connected to the source and the substrate of the second rectification control switch tube (S2) through the first current sampling device (Det1), one end of the second filter inductor (L2) and the cathode of the second freewheeling diode (D4), the anodes of the first freewheeling diode (D3) and the second freewheeling diode (D4) are connected to the negative terminal of the dc power supply, the other end of the second filter inductor (L2) is connected to the shunt MOSFET dimming circuit and the LED array for lighting dimming through the second current sampling device (Det2), and the first current sampling device Det1, the second current sampling device Det2 and the gates of the first rectification control switch tube S1 and the second rectification control switch tube S2 are connected to the MCU main control circuit.
3. An LED driver circuit as claimed in claim 2, wherein the LED driver circuit is configured to control the LED driver circuit independently of the visible light communication, and further comprises: the parallel MOSFET dimming circuit comprises an illumination dimming MOSFET switch tube (S3), the parallel MOSFET switch tube is connected to two ends of the LED array for illumination dimming, the drain electrode of the parallel MOSFET switch tube is also connected with the second filter inductor, and the grid electrode of the parallel MOSFET switch tube is connected with the MCU main control circuit.
4. An LED driver circuit as claimed in claim 3, wherein the LED driver circuit is configured to control the LED driver circuit independently of the visible light communication, and further comprises: the light communication modulation MOSFET circuit comprises a MOSFET switch tube (S4), the MOSFET switch tube is connected to two ends of the LED array for light communication in parallel, the drain electrode of the MOSFET switch tube is also connected with the source electrode and the substrate of the lighting dimming MOSFET switch tube (S3), and the grid electrode of the MOSFET switch tube is connected with the optical coupling isolation driving circuit.
5. An LED driver circuit as claimed in claim 4, wherein: the LED array for illumination and dimming and the LED array for optical communication modulation comprise a plurality of illumination LED lamps or optical communication LED lamps which are combined in series and parallel according to requirements.
6. An LED driver as claimed in claim 4 with independently controllable lighting and visible light communicationA circuit, characterized by: the MCU master control circuit comprises a microprocessor, and the internal A/D based on the microprocessor completes the inductive current (i) of the current type BUCK circuit, which comprises a filter inductor L1L1) A direct current output current (i)dc) The current collection is completed by a universal input/output (IO) port and comprises the output of a direct current set value (I)dcref) Reading an externally given signal of a dimming set point (DIM _ set), while the microprocessor is dependent on the inductor current (i)L1) A direct current output current (i)dc) DC set value (I)dcref) Constant current and current sharing control are achieved through a PI control algorithm, and Pulse Width Modulation (PWM) control signals (PWM1 and PWM2) of the first rectification control switch tube (S1) and the second rectification control switch tube (S2) are generated to the grids of the first rectification control switch tube (S1) and the second rectification control switch tube (S2) through a PWM generator respectively.
7. An LED driver circuit as claimed in claim 6, wherein: the optical coupling isolation driving circuit comprises an optical coupling isolation circuit and a high-speed driving circuit, the MCU main control circuit reads a high-speed signal VPPM needing to be transmitted through a general input/output interface I/O port and outputs the high-speed signal VPPM to the optical coupling isolation driving circuit, so that the high-speed VPPM signal is transmitted to the optical communication modulation MOSFET circuit after being isolated by the optical coupling and driven at a high speed.
8. An LED driver circuit as claimed in claim 7, wherein: the MCU master control circuit loads a modulation signal to the grid of the optical communication modulation MOSFET switching tube (S4) through the optical coupling isolation driving circuit so as to control the optical communication modulation MOSFET switching tube to be switched on and off at a high speed, so that the LED light source of the LED array for optical communication modulation generates light and dark changes, an electric signal is converted into an optical signal, and visible light communication based on the LED light source is realized.
9. An LED driver circuit as claimed in claim 6, wherein: the microprocessor of the MCU main control circuit reads an external dimming set value (DIM _ set) and converts the external dimming set value into a PWM signal with adjustable duty ratio, and the PWM signal is generated by the PWM generator and is connected to a driving control signal of a lighting dimming MOSFET switch tube (S3) of the MOSFET dimming circuit, so that the PWM dimming function is realized.
10. An LED driver circuit for independent control of illumination and visible light communication as claimed in claim 9, wherein: the dimming frequency is set between 200Hz and 2 kHz.
Technical Field
The invention relates to the technical field of LED (Light Emitting Diode) driving, in particular to an LED driving circuit capable of independently controlling illumination and visible Light communication.
Background
The led (light Emitting diodes) has many advantages such as energy saving, long life, environmental protection, and fast response speed, and is an illumination light source with excellent performance. Visible Light Communication (VLC) is a novel wireless Communication technology that loads a specific signal to the intensity of Light for transmission and simultaneously realizes dual functions of illumination and Communication on the basis of the characteristics of high LED response speed and easiness in modulation. The LED illumination and the visible light communication are combined, the illumination and communication integration is realized, and the application prospect of the LED can be further expanded.
Generally, to realize communication, LEDs must be modulated at high speed, but like PWM dimming, high-speed modulation of LEDs destroys the optical power spectrum of the LEDs, causing flickering of lighting. At present, LED dimming and optical communication modulation are generally realized by adopting the same group of LED arrays, which inevitably causes mutual influence of the LED dimming and the optical communication modulation and further influences the reliability of data transmission.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide an LED driving circuit capable of independently controlling illumination and visible light communication, so that the LED illumination circuit and the visible light communication modulation circuit can work together and respectively and independently, thereby not only meeting the normal LED illumination requirements, but also realizing wireless data transmission based on visible light communication.
To achieve the above and other objects, the present invention provides an LED driving circuit capable of independently controlling illumination and visible light communication, comprising:
the direct current power supply is used for providing power for the circuit;
the current type BUCK circuit is used for converting the direct current power supply of the voltage source into a direct current source with controllable and adjustable current amplitude so as to drive a rear-stage LED array for illumination dimming or an LED array for optical communication modulation and complete corresponding current sampling;
the parallel MOSFET dimming circuit is connected with the current type BUCK circuit, is connected to two ends of the LED array for lighting and dimming in parallel and is used for realizing the PWM dimming function of the LED array for lighting and dimming under the control of the MCU main control circuit;
the LED array for lighting dimming comprises a plurality of lighting LED lamps so as to carry out PWM dimming according to the parallel MOSFET dimming circuit;
the optical communication modulation MOSFET circuit is connected with the current type BUCK circuit, is connected to two ends of the LED array for optical communication in parallel, and is used for realizing the high-speed modulation function of a transmission signal under the output control of the optical coupling isolation driving circuit;
the LED array for optical communication modulation comprises a plurality of optical communication LED lamps so as to realize visible light communication based on an LED light source according to the optical communication modulation MOSFET circuit;
the MCU master control circuit is used for collecting current of the current type BUCK circuit, acquiring an external given signal, generating a Pulse Width Modulation (PWM) control signal for controlling the parallel MOSFET dimming circuit through a PWM generator, and acquiring a high-speed VPPM signal to be transmitted and outputting the high-speed VPPM signal to the optical coupling isolation driving circuit;
and the optical coupling isolation driving circuit is used for receiving and processing the high-speed VPPM signal sent by the MCU main control circuit, and outputting a communication control signal to the optical communication modulation MOSFET circuit after optical coupling isolation and high-speed driving processing.
Preferably, the current type BUCK circuit comprises a first switch diode (D1), a second switch diode (D2), a first freewheel diode (D3), a second freewheel diode (D4), a first rectification control switch tube (S1), a second rectification control switch tube (S2), a first filter inductor (L1), a second filter inductor (L2), a first current sampling device (Det1), a second current sampling device (Det2), a positive terminal of the dc power supply is connected to anodes of the first switch diode (D1), the second switch diode (D2), a cathode of the first switch diode (D1) is connected to a drain of the first rectification control switch tube (S1), a source of the first rectification control switch tube (S1) and a substrate are connected to one end of the first filter inductor (L1) and a cathode of the first freewheel diode (D3), the cathode of the second switch diode (D2) is connected to the drain of the second rectification control switch tube (S2), the other end of the first filter inductor (L1) is connected to the source and the substrate of the second rectification control switch tube (S2), one end of the second filter inductor (L2) and the cathode of a second free-wheeling diode (D4) through the first current sampling device (Det1), the anodes of the first freewheeling diode (D3) and the second freewheeling diode (D4) are connected to the negative terminal of the DC power supply, the other end of the second filter inductor (L2) is connected to the shunt MOSFET dimming circuit and the LED array for lighting dimming via the second current sampling device (Det2), the first current sampling device Det1, the second current sampling device Det2, the first rectification control switch tube S1 and the gate of the second rectification control switch tube S2 are connected with the MCU main control circuit.
Preferably, the shunt MOSFET dimming circuit includes a lighting dimming MOSFET switch tube (S3), which is connected in parallel to two ends of the lighting dimming LED array, and the drain of the shunt MOSFET dimming circuit is further connected to the second filter inductor, and the gate of the shunt MOSFET dimming circuit is connected to the MCU main control circuit.
4. An LED driver circuit as claimed in claim 3, wherein the LED driver circuit is configured to control the LED driver circuit independently of the visible light communication, and further comprises: the light communication modulation MOSFET circuit comprises a MOSFET switch tube (S4), the MOSFET switch tube is connected to two ends of the LED array for light communication in parallel, the drain electrode of the MOSFET switch tube is also connected with the source electrode and the substrate of the lighting dimming MOSFET switch tube (S3), and the grid electrode of the MOSFET switch tube is connected with the optical coupling isolation driving circuit.
Preferably, the illumination dimming LED array and the optical communication modulation LED array include a plurality of illumination LED lamps or optical communication LED lamps combined in series and parallel as necessary.
Preferably, the MCU master control circuit comprises a microprocessor, and the inductor current (i) comprising the filter inductor L1 of the current type BUCK circuit is completed based on the internal A/D of the microprocessorL1) A direct current output current (i)dc) The current collection is completed by a universal input/output (IO) port and comprises the output of a direct current set value (I)dcref) Reading an externally given signal of a dimming set point (DIM _ set), while the microprocessor is dependent on the inductor current (i)L1) A direct current output current (i)dc) DC set value (I)dcref) Constant current and current sharing control is realized by using a PI control algorithm, and pulse width modulation PW of the first rectification control switch tube S1 and the second rectification control switch tube S2 is respectively generated by a PWM generatorM control signals PWM1 and PWM2 are sent to the grids of the first rectification control switch tube S1 and the second rectification control switch tube S2.
Preferably, the optical coupling isolation driving circuit comprises an optical coupling isolation circuit and a high-speed driving circuit, and the MCU main control circuit reads a high-speed signal VPPM to be transmitted through a general input/output interface I/O port and outputs the high-speed signal VPPM to the optical coupling isolation driving circuit, so as to transmit the high-speed VPPM signal to the optical communication modulation MOSFET circuit after optical coupling isolation and high-speed driving processing.
Preferably, the MCU master control circuit loads a modulation signal to the gate of the optical communication modulation MOSFET switching tube (S4) through the optical coupling isolation driving circuit to control high-speed on and off thereof, so that the LED light source of the LED array for optical communication modulation generates light or dark change, and the electrical signal is converted into an optical signal to realize visible light communication based on the LED light source.
Preferably, the microprocessor of the MCU main control circuit reads an external dimming set value (DIM _ set) and converts the external dimming set value (DIM _ set) into a PWM signal with an adjustable duty ratio, and the PWM generator generates and connects a driving control signal of the lighting dimming MOSFET switch tube (S3) of the MOSFET dimming circuit to implement a PWM dimming function.
Preferably, the dimming frequency is set between 200Hz and 2 kHz.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention adopts the same circuit, thereby not only meeting the requirements of general illumination, but also meeting the requirements of visible light communication.
2. The illumination light source and the communication light source adopt mutually independent control modes, so that the illumination effect is not influenced by the on-off change generated by the communication light source in the signal transmission process.
3. The communication light source of the invention can also realize high-power work, thereby easily increasing the signal transmission distance.
4. The LED load control system adopts digital control, can adjust the LED load for illumination and optical communication at any time, and greatly improves the capability of the driving power supply to adapt to different loads.
Drawings
FIG. 1 is a circuit diagram of an LED driver circuit with independent control of illumination and visible light communication in accordance with the present invention;
FIG. 2 is a diagram illustrating dimming and optical communication modulation signals in the operating mode I according to an embodiment of the present invention;
FIG. 3 is a diagram illustrating dimming and optical communication modulation signals in the second operating mode of the embodiment of the present invention;
fig. 4 is a schematic diagram of dimming and optical communication modulation signals in the operating mode iii according to the embodiment of the present invention.
Detailed Description
Other advantages and capabilities of the present invention will be readily apparent to those skilled in the art from the present disclosure by describing the embodiments of the present invention with specific embodiments thereof in conjunction with the accompanying drawings. The invention is capable of other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention.
Fig. 1 is a circuit configuration diagram of an LED driving circuit capable of independently controlling illumination and visible light communication according to the present invention. As shown in fig. 1, the LED driving circuit capable of independently controlling illumination and visible light communication according to the present invention includes: the LED lighting device comprises a direct-current power supply 1, a current type BUCK circuit 2, a parallel MOSFET dimming circuit 3, an LED array 4 for lighting dimming, an optical communication modulation MOSFET circuit 5, an LED array 6 for optical communication modulation, an MCU main control circuit 7 and an optical coupling isolation driving circuit 8.
The direct current power supply 1 is DC24V or DC48V and is used for supplying power to the circuit; the current type BUCK circuit 2 consists of a switch diode D1-D2, a freewheeling diode D3-D4, a rectification control switch tube S1-S2, a filter inductor L1-L2 and a current sampling device Det1-Det2, and is used for converting a voltage source direct current power supply 1 into a direct current source with controllable and adjustable current amplitude to drive a rear-stage LED array 4 for illumination dimming or an LED array 6 for optical communication modulation and complete corresponding current sampling;the shunt MOSFET dimming circuit 3 consists of an illumination dimming MOSFET switch tube S3, is connected in parallel at two ends of the illumination dimming LED array 4 and is used for realizing the PWM dimming function of the illumination dimming LED array 4 by controlling the on-off of the MSOFET switch tube; the LED array 4 for lighting and dimming consists of a plurality of lighting LED lamps LED11-LEDmn, and can be combined in series and parallel according to the actual lighting requirement, wherein n are connected in series to form 1 group, and then m are connected in parallel; the optical communication modulation MOSFET circuit 5 consists of an MOSFET switch tube S4, is connected in parallel at two ends of the LED array 6 for optical communication, and is used for realizing the high-speed modulation function of transmission signals by controlling the on-off of the MSOFET switch tube; the LED array 6 for optical communication modulation consists of a plurality of optical communication LED lamps DD11-DDpq, and can be combined in series and parallel according to actual lighting needs, wherein q groups are shown in series to form 1 group, and then p groups are connected in parallel; the MCU master control circuit 7 consists of a microprocessor STM32, and the current acquisition of the current type BUCK circuit 2 is completed based on the internal A/D of the microprocessor STM32 (including the inductive current i of the filter inductor L1)L1DC output current idc) Finishing the reading of external given signals through a general input/output (IO) port (including outputting a direct current set value I)dcrefAnd dimming set value DIM _ set), and simultaneously, the microprocessor realizes constant current and current sharing control by using a PI control algorithm and the PWM generator respectively generates MOSFET switching tubes S1、S2、S3The pulse width modulation PWM control signals PWM1, PWM2 and V _ DIM read the high-speed signal VPPM _ Data to be transmitted through the I/O port of the universal input/output interface and output the high-speed signal VPPM _ Data to the input end of the optical coupling isolation driving circuit 8; the optical coupling isolation driving circuit 8 consists of an optical coupling isolation circuit and a high-speed driving circuit, is used for receiving and processing a high-speed VPPM signal sent by the MCU main control circuit 7, outputs a communication control signal V _ Data after optical coupling isolation and high-speed driving processing and transmits the communication control signal V _ Data to an optical communication modulation MOSFET switching tube S of the optical communication modulation MOSFET circuit 54A gate electrode of (1).
Specifically, the positive terminal of the dc power supply 1 is connected to the anodes of the switching diodes D1-D2, the cathode of the switching diode D1 is connected to the drain of the MOSFET switching tube S1, the source and the substrate of the MOSFET switching tube S1 are connected to one end of the filter inductor L1 and the cathode of the freewheeling diode D3, the cathode of the switching diode D2 is connected to the drain of the MOSFET switching tube S2, the other end of the filter inductor L1 is connected to the source and the substrate of the MOSFET switching tube S2, one end of the filter inductor L2 and the cathode of the freewheeling diode D4 through the current sampling device Det1, and the anodes of the freewheeling diodes D3-D4 are connected to the negative terminal of the dc power supply 1;
the other end of the filter inductor L2 is connected to the drain of an illumination dimming MOSFET switch tube S3 and the anodes of illumination LED lamps LED11-LEDm1 through a current sampling device Det2, the source and the substrate of the illumination dimming MOSFET switch tube S3 are connected to the cathodes of the illumination LED lamps LED1 n-LEDn, the anodes of the optical communication LED lamps DD11-DDp1 and the drain of the MOSFET switch tube S4, and the illumination LED lamps LEDi1-LEDin are sequentially connected in series in the same direction to form 1 group of illumination LED lamps (i is 1,2, … …, m); the source electrode and the substrate of the MOSFET switch tube S4 and the cathode of the optical communication LED lamp DD1q-DDmq are connected to the negative end of the direct current power supply 1;
the output direct current set value Idcref and the inductive current i output by the current sampling device Det1-Det2L1DC output current idcThe LED driving circuit is respectively connected to 3 input ends of a constant current and current sharing control circuit, the output of the constant current and current sharing control circuit is connected to one input end of a PWM generator, a dimming set value DIM _ set is connected to the other input end of the PWM generator after being subjected to internal A/D conversion, and pulse width modulation PWM control signals PWM1, PWM2 and V _ DIM output by the PWM generator are respectively connected to gates of rectification control switch tubes S1-S2 and an illumination dimming MOSFET switch tube S3; the high-speed signal VPPM _ Data is connected to the input end of the optical coupling isolation driving circuit 8 through the general input and output IO port, and the output end communication control signal V _ Data of the optical coupling isolation driving circuit 8 is connected to the grid electrode of the MOSFET switching tube S4.
In the invention, the parallel MOSFET dimming circuit 3 and the lighting dimming LED array 4 form a parallel LED dimming circuit, a dimming setting DIM _ set is read by a microprocessor STM32 of the MCU main control circuit 7 and converted into a PWM signal with an adjustable duty ratio, and a driving control signal of the MOSFET switching tube S3 of the parallel MOSFET dimming circuit 3 is generated by a PWM waveform generator, so that the PWM dimming function can be realized.
In the invention, the optical communication modulation MOSFET circuit 5 and the LED array 6 for optical communication modulation form a parallel optical communication modulation circuit, which is suitable for common LED current modulation modes such as On-Off Key (OOK) modulation and Pulse Position Modulation (PPM), the LED array for sending signals is connected with the MOSFET switch tube S4 in parallel, the modulation signal is loaded On the MOSFET switch tube S4 to control high-speed On and Off, so that the LED light source generates light and dark changes, the electric signal is converted into the optical signal, and visible light communication based On the LED light source is realized.
The following description of the operation modes of independent control of illumination and visible light communication in the embodiment of the present invention in conjunction with fig. 2-4:
the dimming frequency was set at 1kHz, and the optical communication modulation frequency was 100 kHz.
(1) The working mode I: illumination is switched on from off to on, optical communication is switched on
As shown in fig. 2, at 0 to 0.0005S, the PWM control signal V _ DIM for controlling the MOSFET switch tube S3 is high, the MOSFET switch tube S3 is turned on, the LED array for lighting dimming is bypassed, which is equivalent to turning off of lighting, and after the time is greater than 0.0005S, the PWM control signal V _ DIM for controlling the MOSFET switch tube S3 is low, the MOSFET switch tube S3 is turned off, the LED array for lighting dimming is turned on, which is equivalent to turning on of lighting; the communication control signal V _ Data has Data, the MOSFET switch tube S4 is turned on/off in turn along with the high/low level of the communication control signal V _ Data, and the LED array for optical communication modulation is turned off/on, which is equivalently that optical communication is turned on.
(2) And a working mode II: illumination is switched off to on and optical communication is switched off
As shown in fig. 3, at 0 to 0.0005S, the PWM control signal V _ DIM for controlling the MOSFET switch tube S3 is high, the MOSFET switch tube S3 is turned on, the LED array for lighting dimming is bypassed, which is equivalent to turning off of lighting, and after the time is greater than 0.0005S, the PWM control signal V _ DIM for controlling the MOSFET switch tube S3 is low, the MOSFET switch tube S3 is turned off, the LED array for lighting dimming is turned on, which is equivalent to turning on of lighting; the communication control signal V _ Data is at a high level, the MOSFET switching tube S4 is turned on, the LED array for optical communication modulation is bypassed (extinguished), which is equivalent to optical communication off;
(3) and a working mode III: illumination is off and optical communication is on
As shown in fig. 4, the PWM control signal V _ DIM for controlling the MOSFET switch tube S3 is high, the MOSFET switch tube S3 is turned on, the LED array for lighting dimming is bypassed, and the lighting is equivalently turned off; the communication control signal V _ Data has Data, the MOSFET switch tube S4 is turned on/off in turn along with the high/low level of the communication control signal V _ Data, and the LED array for optical communication modulation is turned off/on, which is equivalently that optical communication is turned on.
Therefore, the LED driving circuit capable of independently controlling illumination and visible light communication provided by the invention has the advantages that the illumination light source and the communication light source are controlled in an independent control mode, so that the illumination effect cannot be influenced by the on-off change generated by the communication light source in the signal transmission process, and the LED illumination circuit and the visible light communication modulation circuit can work together and respectively and independently, so that the normal LED illumination requirement is met, and the wireless data transmission based on the visible light communication can be realized.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Therefore, the scope of the invention should be determined from the following claims.