CN112383235B - Power supply device for parallel connection of LED outdoor advertising screens - Google Patents
Power supply device for parallel connection of LED outdoor advertising screens Download PDFInfo
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- CN112383235B CN112383235B CN202011591275.9A CN202011591275A CN112383235B CN 112383235 B CN112383235 B CN 112383235B CN 202011591275 A CN202011591275 A CN 202011591275A CN 112383235 B CN112383235 B CN 112383235B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M7/23—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only arranged for operation in parallel
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
- G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
- G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
- G09F9/33—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being semiconductor devices, e.g. diodes
Abstract
The invention discloses a power supply device for parallel connection of LED outdoor advertising screens, which comprises a PFC and PWM switch control module, a transformer T and a rectification filter module, wherein the PFC and PWM switch control module converts alternating current into direct current and transmits electric energy to the rectification filter module through the transformer T under the control of PWM, and overcurrent, constant current and constant voltage control is carried out according to a feedback signal of a feedback circuit; the rectification filtering module converts the direct current amplitude value, supplies power to the DC-DC module and supplies power to the first group of LEDs through the first direct current output end; the DC-DC module converts the amplitude of the direct current sent by the rectifying and filtering module and supplies power to the second group of LEDs through a second direct current output end; the intelligent power supply mode is provided according to different primary color lamps of the LED outdoor advertising screen, and the multiple power supply devices are connected in parallel for use according to the increase of the lamp beads of the advertising screen, so that each power supply device supplies power for the advertising screen with average current.
Description
Technical Field
The invention relates to a power supply device, in particular to a power supply device for parallel connection of LED outdoor advertising screens.
Background
At present, the social environment and various outdoor LED advertising screens are widely applied to various scenes and are closely related to the aspects of people's life in the economic society. Because the outdoor LED advertising screen is manufactured based on the luminous characteristics of the LEDs, the VF values of the three primary colors RGB of the LEDs are different (the VF value of the red LED is 2.8-3.2V, and the VF value of the green/blue LED is 3.8-4.3V). The current general method is that single-path output is carried out, the VF value of RGB three-color LEDs is not considered, and high voltage is directly used for driving all LEDs with different primary colors, so that the problems of high energy consumption and no environmental protection are caused, and the service life of the LEDs is greatly shortened; another way is to use two power supply devices with different output voltages to respectively supply power to the LEDs with different primary colors, wherein one power supply device is used for the red R path and one power supply device is used for the green/blue GB path, which results in complex circuit, high cost, poor consistency, complex production and difficult maintenance.
In addition, if the outdoor advertising screen needs to extend to increase the size of the lamp bead, the power needed at this time is higher, the power supply modules need to be considered for parallel use, and if the power supply device does not have the function of current adaptive load change, the risk that the current of the power supply device may exceed the rated current and be damaged is caused.
Therefore, there is a need to design an outdoor LED power supply device capable of outputting two different voltages (currents) through two sets, and the two sets are conveniently connected in parallel.
Disclosure of Invention
In order to solve the defects in the prior art, the invention provides a power supply device for parallel connection of LED outdoor advertising screens.
The technical scheme adopted by the invention is that the power supply device for the LED outdoor advertising screen which is used in parallel is designed, and comprises an alternating current input end, a PFC and PWM switch control module, a transformer T, a rectification filter module and a first direct current output end which are sequentially connected, wherein the output end of the rectification filter module is connected with a DC-DC module, the output end of the DC-DC module is connected with a second direct current output end, and a feedback circuit is arranged between the first direct current output end and the second direct current output end and between the PFC and PWM switch control module; the PFC and PWM switch control module converts alternating current into direct current, is controlled by PWM, transmits electric energy to the rectification filter module through a transformer T, and performs overcurrent, constant current and constant voltage control according to a feedback signal of the feedback circuit; the rectification filtering module converts the direct current amplitude value, supplies power to the DC-DC module and supplies power to the first group of LEDs through the first direct current output end; the DC-DC module converts the amplitude of the direct current sent by the rectifying and filtering module and supplies power to the second group of LEDs through the second direct current output end.
The feedback circuit comprises a first loop control module and a second loop control module, a voltage detector and a first current detector are connected between the rectifying and filtering module and the first direct current output end, the voltage detector and the first current detector are connected with the first loop control module, and the first loop control module is connected with the PFC and PWM switch control module through a first optical coupler OC 1; a second current detector is connected between the DC-DC module and a second direct current output end, the first current detector and the second current detector are connected with a second loop control module, and the second loop control module is connected with a PFC and PWM switch control module through a second optical coupler OC 2; the PFC and PWM switch control module receives signals fed back by a first optical coupler OC1 and a second optical coupler OC2 to perform overcurrent, constant current and constant voltage control; the first loop control module triggers a first optical coupler OC1 according to the voltage and current values of the first direct current output end, and the first optical coupler OC1 is triggered during overcurrent and overvoltage; the second loop control module triggers a second optical coupler OC2 according to the current value of the first direct current output end and the current value of the second direct current output end, and the second optical coupler OC2 triggers when the current is unbalanced with the current of the first direct current output end and the current of the second direct current output end.
The second loop control module is further connected with a parallel signal connecting terminal, the LED outdoor advertising screen is connected in parallel to use the power supply device to be connected in parallel with another LED outdoor advertising screen through the parallel signal connecting terminal, and the power supply device is connected in parallel to use the power supply device to be connected in parallel and carry out current sharing control.
The first loop control module comprises a first operational amplifier IC1A, a second operational amplifier IC1B, a working power supply VDD1, a first direct current output voltage end Vout +, a first current detector feedback end IS-1, a working power supply VDD1 connected with one ends of a first resistor R1 and a fourth resistor R4, the other end of the fourth resistor R4 connected with a non-inverting input end of the first operational amplifier IC1A, a tenth resistor R10 and one end of a third capacitor C3, the other end of the tenth resistor R10 connected with a non-inverting input end of the second operational amplifier IC1B, an eleventh resistor R11 and one end of a sixth capacitor C6, a first direct current output voltage end Vout + connected with one end of a fifth resistor R5, the other end of the fifth resistor R5 connected with an inverting input end of the first operational amplifier IC1A, one end of the sixth resistor R6, one end of a first capacitor C1 and one end of a second capacitor C2, the other end of the second capacitor C2 connected with one end of the first operational amplifier IC1 and one end of the first resistor R3 and the seventh capacitor R3, the other end of the seventh resistor R7 IS connected with the cathode of the first diode D1, the anode of the first diode D1 IS connected with one end of the second resistor R2, the cathode of the second diode D2 and the cathode of the first optical coupler OC1, the other ends of the second resistor R2 and the first resistor R1 are connected with the anode of the first optical coupler OC1, the feedback end IS-1 of the first current detector IS connected with one end of the twelfth resistor R12, the other end of the twelfth resistor R12 IS connected with the inverting input end of the second operational amplifier IC2A, one end of the seventh resistor R7, one end of the fourth capacitor C4 and one end of the fifth capacitor C5, the other end of the fifth capacitor C5 IS connected with one end of the ninth resistor R9, the other ends of the fourth capacitor C4 and the ninth resistor R9 are connected with one end of the eighth resistor R8 and the output end of the second operational amplifier IC2A, the other end of the eighth resistor R8 IS connected with the cathode of the second diode D2 and the sixth resistor R6, the other ends of the third capacitor C3, the sixth capacitor C6, the seventh resistor R7 and the eleventh resistor R11 are grounded.
The second loop control module comprises a first current detector feedback end IS-1, a second current detector feedback end IS-2, a parallel signal connection terminal positive VBus +, a parallel signal connection terminal negative VBus-, a working power supply VDD1 IS connected with one end of a thirteenth resistor R13, the other end of a thirteenth resistor R13 IS connected with the anode of a second optocoupler OC2, the first current detector feedback end IS-1 IS connected with one end of a fourteenth resistor R14, the other end of the fourteenth resistor R14 IS connected with the reverse input end of a third operational amplifier IC2A and one end of a sixteenth resistor R16, the second current detector feedback end IS-2 IS connected with one end of a fifteenth resistor R15, the other end of the fifteenth resistor R15 IS connected with the reverse input end of a fourth operational amplifier IC2B and one end of a seventeenth resistor R17, the same-direction input ends of the third operational amplifier IC2A and the fourth operational amplifier IC2B are grounded, and the output end of the third operational amplifier IC2A and the fourth operational amplifier IC2B IS connected with the sixteenth resistor R16, The other end of a seventeenth resistor R17, one end of an eighth capacitor C8 and one end of a nineteenth resistor R19, the other end of an eighth capacitor C8 is connected with the reverse input end of the eighth operational amplifier IC4B, the other end of a nineteenth resistor R19 is connected with one end of a twenty-first resistor R21 and the same-direction input end of a fifth operational amplifier IC3A, a negative VBus-of a parallel signal connection terminal is connected with the other end of a twenty-first resistor R21, the cathode of a third diode, one end of a twenty-fifth resistor R25 and one end of a twentieth resistor R20, the other end of a twentieth resistor R20 is connected with one end of a tenth capacitor C10 and an eighteenth resistor R18 and the reverse input end of a fifth operational amplifier IC3A, the other end of the eighteenth resistor R42 is grounded, the output end of the fifth operational amplifier IC3A is connected with the other end of a tenth capacitor C10 and the anode of a third diode, the positive us + of the parallel signal connection terminal is connected with one end of a twenty-second resistor R22, the other end of the twenty-direction input end of the twenty-second resistor R23 and the sixth operational amplifier IC 57324, the other end of the twenty-third resistor R23 is grounded, the inverting input terminal of the sixth operational amplifier IC3B is connected to the other end of the twenty-fifth resistor R25, one end of the twenty-sixth resistor R26 and one end of the eleventh capacitor C11, the other end of the eleventh capacitor C11 is connected to one end of the twenty-fourth resistor R24, the output terminal of the sixth operational amplifier IC3B is connected to the other ends of the twenty-fourth resistor R24 and the twenty-sixth resistor R26, one end of the twelfth capacitor C12 and the homodromous input terminal of the eighth operational amplifier IC4B, the output terminal of the eighth operational amplifier IC4B is connected to the other end of the twelfth capacitor C12, one end of a ninth capacitor C9 and the cathode of a zener diode ZD1, the other end of the ninth capacitor C9 is connected with the equidirectional input end of the seventh operational amplifier IC4A, the output end of the seventh operational amplifier IC4A is connected with the base of a first triode Q1, the collector of the first triode Q1 is connected with the cathode of a second optocoupler OC2, and the emitter of the first triode Q1, the reverse input end of the seventh operational amplifier IC4A and the anode of the zener diode ZD1 are grounded.
The first set of LEDs is green/blue LEDs.
The DC-DC module adopts a voltage reduction DC-DC module, and the second group of LEDs are red LEDs.
The technical scheme provided by the invention has the beneficial effects that:
according to the invention, an intelligent power supply mode is provided according to different primary color lamps of the LED outdoor advertising screen, and the voltage switching is efficient and energy-saving; the invention has the function of current self-adapting load change, and carries out current sharing comparison control through the current adjusting terminal and the current detection control module, so that each power supply device supplies power for the advertisement screen with average current, thereby avoiding the conditions of shortened service life of the power supply device, abnormal work of the advertisement screen and the like caused by unbalanced power supply of each power supply device.
Drawings
The invention is described in detail below with reference to examples and figures, in which:
FIG. 1 is a functional block diagram of a preferred embodiment;
FIG. 2 is a functional block diagram of two power supply units used in parallel;
FIG. 3 is a first loop control module circuit diagram;
figure 4 is a circuit diagram of a second loop control module.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The invention is based on a flyback circuit with PFC, has the functions of constant voltage and constant current, provides an intelligent power supply mode according to different primary color lamps of the LED outdoor advertising screen through current detection signal feedback, and has high-efficiency and energy-saving voltage switching; the invention has the function of current self-adapting load change, and carries out current sharing comparison control through the current adjusting terminal and the current detection control module, so that each power supply device supplies power for the advertisement screen with average current, thereby avoiding the conditions of shortened service life of the power supply device, abnormal work of the advertisement screen and the like caused by unbalanced power supply of each power supply device.
The invention discloses a power supply device for parallel connection of LED outdoor advertising screens, which comprises an alternating current input end, a PFC and PWM switch control module, a transformer T, a rectification filter module and a first direct current output end which are sequentially connected, wherein the output end of the rectification filter module is connected with a DC-DC module, the output end of the DC-DC module is connected with a second direct current output end, and a feedback circuit is arranged between the first direct current output end and the second direct current output end as well as the PFC and PWM switch control module; the PFC and PWM switch control module converts alternating current into direct current, is controlled by PWM, transmits electric energy to the rectification filter module through a transformer T, and performs overcurrent, constant current and constant voltage control according to a feedback signal of the feedback circuit; the rectification filtering module converts the direct current amplitude value, supplies power to the DC-DC module and supplies power to the first group of LEDs through the first direct current output end; the DC-DC module converts the amplitude of the direct current sent by the rectifying and filtering module and supplies power to the second group of LEDs through the second direct current output end. In a preferred embodiment, an input protection circuit/EMI module is further disposed between the AC input terminal and the PFC and PWM switch control module.
In the preferred embodiment shown in fig. 1, the feedback circuit includes a first loop control module and a second loop control module, a voltage detector and a first current detector are connected between the rectifying and filtering module and the first dc output terminal, the voltage detector and the first current detector are connected to the first loop control module, and the first loop control module is connected to the PFC and PWM switching control module through a first optical coupler OC 1; a second current detector is connected between the DC-DC module and a second direct current output end, the first current detector and the second current detector are connected with a second loop control module, and the second loop control module is connected with a PFC and PWM switch control module through a second optical coupler OC 2; the PFC and PWM switch control module receives signals fed back by a first optical coupler OC1 and a second optical coupler OC2 to perform overcurrent, constant current and constant voltage control; the first loop control module triggers a first optical coupler OC1 according to the voltage and current values of the first direct current output end, and the first optical coupler OC1 is triggered during overcurrent and overvoltage; the second loop control module triggers a second optical coupler OC2 according to the current value of the first direct current output end and the current value of the second direct current output end, and the second optical coupler OC2 triggers when the current is unbalanced with the current of the first direct current output end and the current of the second direct current output end.
Referring to a schematic block diagram of two power supply devices used in parallel as shown in fig. 2, the second loop control module is further connected with a parallel signal connection terminal, and the power supply device used in parallel of the LED outdoor advertising screen is connected in parallel with another LED outdoor advertising screen through the parallel signal connection terminal, and is connected in parallel with the power supply device and performs current sharing control.
Referring to the circuit diagram of the first loop control module shown in fig. 3, the first loop control module includes a first operational amplifier IC1A, a second operational amplifier IC1B, an operating power supply VDD1, a first dc output voltage terminal Vout +, a first current detector feedback terminal IS-1 (through which the first current detector controls feedback output current to the first loop), an operating power supply VDD1 IS connected to one ends of a first resistor R1 and a fourth resistor R4, the other end of a fourth resistor R4 IS connected to the non-inverting input terminal of the first operational amplifier IC1A, one end of a tenth resistor R10 and one end of a third capacitor C3, the other end of the tenth resistor R10 IS connected to the non-inverting input terminal of the second operational amplifier IC 12, one end of an eleventh resistor R11 and one end of a sixth capacitor C6, a first dc output voltage terminal Vout + IS connected to one end of a fifth resistor R5, the other end of the fifth resistor R5 IS connected to the non-inverting input terminal of the first operational amplifier IC1, one end of the sixth resistor R6, one end of the first capacitor C1 and one end of the second capacitor C2, the other end of the second capacitor C2 IS connected to one end of the third resistor R3, the other ends of the first capacitor C1 and the third resistor R3 are connected to one end of the seventh resistor R7 and the output end of the first operational amplifier IC1A, the other end of the seventh resistor R7 IS connected to the cathode of the first diode D1, the anode of the first diode D1 IS connected to one end of the second resistor R2, the cathode of the second diode D2 and the cathode of the first optical coupler OC1, the other ends of the second resistor R2 and the first resistor R1 are connected to the anode of the first optical coupler OC1, the first current detector feedback end IS-1 IS connected to one end of the twelfth resistor R12, the other end of the twelfth resistor R12 IS connected to the inverting input end of the second operational amplifier IC2A, one end of the seventh resistor R7, one end of the fourth capacitor C7 and one end of the fifth capacitor C7, the other end of the ninth operational amplifier IC 7 IS connected to one end of the ninth resistor R7 and the eighth operational amplifier IC 7, the other end of the eighth resistor R8 is connected to the cathode of the second diode D2, and the other ends of the sixth resistor R6, the third capacitor C3, the sixth capacitor C6, the seventh resistor R7 and the eleventh resistor R11 are grounded.
The working principle of the first loop control module is detailed below with reference to fig. 3, where FB is a controlled signal receiving point of the PWM switch control module; VDD1 is an auxiliary power supply source output by the transformer T; in the circuit, the mode of realizing the output voltage stabilization function is as follows: the voltage Vout + of the first direct current output voltage of the product is divided by resistors R5 and R6 and then is added to the inverting input end of the operational amplifier IC1A, negative feedback signals are transmitted to the FB end through comparison with the reference voltage of the non-inverting input end, comparison operation is carried out through the operational amplifier, then the conduction strength of the optical coupler OC1 is used, and pulse width regulation is carried out through a PWM switch control circuit in the PWM switch control module to ensure the stability of the output voltage. When Vout + is low, negative feedback is reduced, and the input control pulse width is increased; when Vout + is higher, the negative feedback is increased, and the input control pulse width is reduced; thereby ensuring that the output voltage is always within the rated voltage range. The constant current effect is realized in the following mode: the feedback end IS-1 of the first current detector IS added to the inverting input end of the operational amplifier IC1B through a resistor R12 and a timing capacitor C7, a negative feedback signal IS transmitted to the FB end through comparison with a reference voltage of the non-inverting input end, comparison operation of the operational amplifier and then conduction strength of an optical coupler OC1, and then pulse width regulation IS carried out through a PWM switch control circuit in the PWM switch control module to ensure constancy of output current. When IS-1 IS lower, negative feedback IS reduced, and input control pulse width IS increased; when IS-1 IS higher, the negative feedback IS increased, and the input control pulse width IS reduced; thereby ensuring that the output circuit is always in a constant current mode.
Referring to the circuit diagram of the second loop control module shown in fig. 4, the second loop control module includes a first current detector feedback terminal IS-1 through which the first current detector feeds back the output current to the second loop control, a second current detector feedback terminal IS-2 through which the second current detector feeds back the output current to the second loop control, a parallel signal connection terminal positive VBus +, a parallel signal connection terminal negative VBus-, an operating power VDD1 IS connected to one end of a thirteenth resistor R13, the other end of a thirteenth resistor R13 IS connected to an anode of a second opto-coupler OC2, the first current detector feedback terminal IS-1 IS connected to one end of a fourteenth resistor R14, the other end of the fourteenth resistor R14 IS connected to the inverting input terminal of a third operational amplifier IC2A and one end of a sixteenth resistor R16, the second current detector feedback terminal IS-2 IS connected to one end of a fifteenth resistor R15, the other end of the fifteenth resistor R15 is connected with the inverting input end of the fourth operational amplifier IC2B and one end of a seventeenth resistor R17, the equidirectional input ends of the third operational amplifier IC2A and the fourth operational amplifier IC2B are grounded, the output ends of the third operational amplifier IC2A and the fourth operational amplifier IC2B are connected with the other end of the sixteenth resistor R16, the other end of the seventeenth resistor R17, one ends of an eighth capacitor C8 and a nineteenth resistor R19, the other end of the eighth capacitor C8 is connected with the inverting input end of the eighth operational amplifier IC4B, the other end of the nineteenth resistor R19 is connected with one end of the twenty-first resistor R21 and the equidirectional input end of the fifth operational amplifier IC3A, the parallel signal connection terminal is connected with the negative VBus minus one end of the twenty first resistor R21, the cathode of the third diode, one end of the twenty-fifth resistor R25 and one end of the twenty-second resistor R20, the other end of the twentieth resistor R20 is connected with the tenth capacitor C10 and the eighteenth input end of the eighteenth operational amplifier IC 10, the other end of the eighteenth resistor R18 is grounded, the output end of the fifth operational amplifier IC3A is connected with the other end of the tenth capacitor C10 and the anode of the third diode, the positive VBus + of the parallel signal connection terminal is connected with one end of the twenty-second resistor R22, the other end of the twenty-second resistor R22 is connected with one end of the twenty-third resistor R23 and the equidirectional input end of the sixth operational amplifier IC3B, the other end of the twenty-third resistor R23 is grounded, the inverting input end of the sixth operational amplifier IC3B is connected with the other end of the twenty-fifth resistor R25, one end of the twenty-sixth resistor R26 and one end of the eleventh capacitor C11, the other end of the eleventh capacitor C11 is connected with one end of the twenty-fourth resistor R24, the output end of the sixth operational amplifier IC3B is connected with the other ends of the twenty-fourth resistor R24 and the twenty-sixth resistor R26, one end of the twelfth capacitor C12, the equidirectional input end of the eighth operational amplifier IC4B, and the twelfth output end of the eighth operational amplifier IC4B is connected with the twelfth capacitor C12, One end of a ninth capacitor C9 and the cathode of a zener diode ZD1, the other end of the ninth capacitor C9 is connected with the equidirectional input end of the seventh operational amplifier IC4A, the output end of the seventh operational amplifier IC4A is connected with the base of a first triode Q1, the collector of the first triode Q1 is connected with the cathode of a second optocoupler OC2, and the emitter of the first triode Q1, the reverse input end of the seventh operational amplifier IC4A and the anode of the zener diode ZD1 are grounded.
The working principle of the second loop control module is detailed below with reference to fig. 4, where FB is a controlled signal receiving point of the PWM switch control module; VDD1 is the auxiliary power supply for the output of transformer T.
Overcurrent protection: the second loop control module detects output currents of the first direct current output current end and the second direct current output current end, when the output overcurrent is output, after the output overcurrent is calculated and compared through the second loop control module, the output overcurrent is fed back to the PWM switch control module through OC2 to trigger overcurrent protection, and PWM output is turned off. The circuit working principle is as follows: when the two paths of IS-1 and IS-2 output power,
IS-1 and IS-2 output low level after comparison and effective operation through operational amplifier IC2A and IC2B, then output high level after comparison through operational amplifier IC4B and IC4A, and then control Q1 to be conducted through high level, so that the optical coupling OC2 IS conducted, and IS fed back to FB through OC2, and then 2 parts of PWM switch control circuit signal output are cut off, and overcurrent protection IS achieved.
When the multi-power supply device is used in parallel, the current-sharing power limiting function is as follows: the partial circuit is realized in two communication modes.
Signal output mode: when the multi-power supply device is used in parallel, the first current detector and the second current detector feed back the current use condition of the power supply device, and after the operation and comparison of the second loop control module, the parallel signal connection terminals VBus + and VBus-output the current use condition to other parallel power supply devices to control the other parallel power supply devices to adapt to load change adjustment. The circuit working principle is as follows: when the multi-power supply devices are used in parallel, VBus + and VBus-are respectively connected with VBus + and VBus-of other power supply devices; VBus + is used as a reference control signal, VBus-is a current adaptive load change signal; when the device IS used by internal overcurrent, the IS-1 and the IS-2 output low level after comparison and effective operation through the operational amplifier IC2A and the IC2B, the low level IS added to the non-inverting input end of the operational amplifier IC3A, so that the IC3A also outputs low level, D3 IS cut off, and at the moment, VBus-outputs low level signals to other power supply devices used in parallel; when the device IS used by small current, IS-1 and IS-2 output high level after the comparison operation of the operational amplifier IC2A and IC2B, the high level IS added to the non-inverting input end of the operational amplifier IC3A, so that the IC3A also outputs high level, D3 IS conducted, and at the moment, VBus-outputs high level signals to other power supply devices used in parallel.
Signal input mode: when the multi-power supply device is used in parallel, the current using conditions of other power supplies are detected through the first current detector and the second current detector, and after the current using conditions are calculated and compared through the second loop control module, the current using conditions are fed back to the PFC and PWM switch control module through the OC2 to carry out pulse width regulation and control, so that the power output of the power supply is limited, and the output power and the output current of the power supply device are balanced with those of other power supply devices used in parallel. The circuit working principle is as follows: when the multi-power supply devices are used in parallel, VBus + and VBus-are respectively connected with VBus + and VBus-of other power supply devices; VBus + is used as a reference control signal, VBus-is a current adaptive load change signal; when other devices are used by internal overcurrent, VBus-input received by the machine is low level signal, at this time, the level added to the non-inverting input end of the operational amplifier IC3A is higher than the inverting input end, IC3A outputs high level, D3 is conducted, VBus-is raised to high level and the potential is higher than VBus +, at this time, VBus-added to the inverting input end of the operational amplifier IC3B is compared with VBus + reference signal of the non-inverting input end, IC3B outputs low level and is added to the non-inverting input end of the operational amplifier IC4B, so that the operational amplifier IC4B outputs low level, the low level is added to the non-inverting input end of the operational amplifier IC4A, IC4A outputs low level, Q1 is cut off, negative feedback is reduced, input control pulse width is increased, and power output power is increased; when the internal small current of other devices is used, VBus-input received by the machine is high level signal, then the output of IC3A is low level, D3 is cut off, then VBus-potential is lower than VBus +, VBus-is added to the inverting input end of operational amplifier IC3B and compared with VBus + reference signal of the non-inverting input end, the output of IC3B is high level and added to the non-inverting input end of operational amplifier IC4B, further the output of operational amplifier IC4B is high level, the high level is added to the non-inverting input end of operational amplifier IC4A, the output of IC4A is high level, Q1 is conducted, negative feedback is increased, input control pulse width is reduced, and power output power is reduced; therefore, the output power and the output current of the power supply device are balanced with other power supply devices used in parallel.
The first set of LEDs is green/blue LEDs.
The DC-DC module adopts a voltage reduction DC-DC module, and the second group of LEDs are red LEDs.
The foregoing examples are illustrative only and are not intended to be limiting. Any equivalent modifications or variations without departing from the spirit and scope of the present application should be included in the claims of the present application.
Claims (4)
1. The utility model provides a parallelly connected power supply unit that uses of LED outdoor advertising screen which characterized in that: the transformer T comprises an alternating current input end, a PFC and PWM switch control module, a transformer T, a rectification filter module and a first direct current output end which are sequentially connected, wherein the output end of the rectification filter module is connected with a DC-DC module, the output end of the DC-DC module is connected with a second direct current output end, and a feedback circuit is arranged between the first direct current output end and the second direct current output end and between the PFC and PWM switch control module and the second direct current output end;
the PFC and PWM switch control module converts alternating current into direct current, is controlled by PWM, transmits electric energy to the rectification filter module through a transformer T, and performs overcurrent, constant current and constant voltage control according to a feedback signal of the feedback circuit;
the rectification filtering module converts the direct current amplitude value, supplies power to the DC-DC module and supplies power to the first group of LEDs through the first direct current output end;
the DC-DC module converts the amplitude of the direct current sent by the rectifying and filtering module and supplies power to the second group of LEDs through a second direct current output end;
the feedback circuit comprises a first loop control module and a second loop control module, a voltage detector and a first current detector are connected between the rectifying and filtering module and the first direct current output end, the voltage detector and the first current detector are connected with the first loop control module, and the first loop control module is connected with the PFC and PWM switch control module through a first optical coupler OC 1; a second current detector is connected between the DC-DC module and a second direct current output end, the first current detector and the second current detector are connected with a second loop control module, and the second loop control module is connected with a PFC and PWM switch control module through a second optical coupler OC 2; the PFC and PWM switch control module receives signals fed back by a first optical coupler OC1 and a second optical coupler OC2 to perform overcurrent, constant current and constant voltage control;
the first loop control module triggers a first optical coupler OC1 according to the voltage and current values of the first direct current output end;
the second loop control module triggers a second optical coupler OC2 according to the current value of a first direct current output end and the current value of a second direct current output end, and the second optical coupler OC2 is triggered when the current is unbalanced with the current of the first direct current output end and the current of the second direct current output end;
the second loop control module is also connected with a parallel signal connecting terminal, the LED outdoor advertising screen is connected in parallel with a power supply device through the parallel signal connecting terminal and is connected in parallel with another LED outdoor advertising screen through the power supply device, and current sharing control is performed;
the second loop control module comprises a first current detector feedback end IS-1, a second current detector feedback end IS-2, a parallel signal connection terminal positive VBus +, a parallel signal connection terminal negative VBus-, a working power supply VDD1 IS connected with one end of a thirteenth resistor R13, the other end of a thirteenth resistor R13 IS connected with the anode of a second optocoupler OC2, the first current detector feedback end IS-1 IS connected with one end of a fourteenth resistor R14, the other end of the fourteenth resistor R14 IS connected with the reverse input end of a third operational amplifier IC2A and one end of a sixteenth resistor R16, the second current detector feedback end IS-2 IS connected with one end of a fifteenth resistor R15, the other end of the fifteenth resistor R15 IS connected with the reverse input end of a fourth operational amplifier IC2B and one end of a seventeenth resistor R17, the same-direction input ends of the third operational amplifier IC2A and the fourth operational amplifier IC2B are grounded, and the output end of the third operational amplifier IC2A and the fourth operational amplifier IC2B IS connected with the sixteenth resistor R16, The other end of a seventeenth resistor R17, one end of an eighth capacitor C8 and one end of a nineteenth resistor R19, the other end of an eighth capacitor C8 is connected with the reverse input end of the eighth operational amplifier IC4B, the other end of a nineteenth resistor R19 is connected with one end of a twenty-first resistor R21 and the same-direction input end of a fifth operational amplifier IC3A, a negative VBus-of a parallel signal connection terminal is connected with the other end of a twenty-first resistor R21, the cathode of a third diode, one end of a twenty-fifth resistor R25 and one end of a twentieth resistor R20, the other end of a twentieth resistor R20 is connected with one end of a tenth capacitor C10 and an eighteenth resistor R18 and the reverse input end of a fifth operational amplifier IC3A, the other end of the eighteenth resistor R42 is grounded, the output end of the fifth operational amplifier IC3A is connected with the other end of a tenth capacitor C10 and the anode of a third diode, the positive us + of the parallel signal connection terminal is connected with one end of a twenty-second resistor R22, the other end of the twenty-direction input end of the twenty-second resistor R23 and the sixth operational amplifier IC 57324, the other end of the twenty-third resistor R23 is grounded, the inverting input terminal of the sixth operational amplifier IC3B is connected to the other end of the twenty-fifth resistor R25, one end of the twenty-sixth resistor R26 and one end of the eleventh capacitor C11, the other end of the eleventh capacitor C11 is connected to one end of the twenty-fourth resistor R24, the output terminal of the sixth operational amplifier IC3B is connected to the other ends of the twenty-fourth resistor R24 and the twenty-sixth resistor R26, one end of the twelfth capacitor C12 and the homodromous input terminal of the eighth operational amplifier IC4B, the output terminal of the eighth operational amplifier IC4B is connected to the other end of the twelfth capacitor C12, one end of a ninth capacitor C9 and the cathode of a zener diode ZD1, the other end of the ninth capacitor C9 is connected with the equidirectional input end of the seventh operational amplifier IC4A, the output end of the seventh operational amplifier IC4A is connected with the base of a first triode Q1, the collector of the first triode Q1 is connected with the cathode of a second optocoupler OC2, and the emitter of the first triode Q1, the reverse input end of the seventh operational amplifier IC4A and the anode of the zener diode ZD1 are grounded.
2. The LED outdoor advertising screen parallel use power supply device according to claim 1, characterized in that: the first loop control module comprises a first operational amplifier IC1A, a second operational amplifier IC1B, a working power supply VDD1, a first direct current output voltage end Vout +, a first current detector feedback end IS-1, a working power supply VDD1 connected with one ends of a first resistor R1 and a fourth resistor R4, the other end of the fourth resistor R4 connected with a non-inverting input end of the first operational amplifier IC1A, a tenth resistor R10 and one end of a third capacitor C3, the other end of the tenth resistor R10 connected with a non-inverting input end of the second operational amplifier IC1B, an eleventh resistor R11 and one end of a sixth capacitor C6, a first direct current output voltage end Vout + connected with one end of a fifth resistor R5, the other end of the fifth resistor R5 connected with an inverting input end of the first operational amplifier IC1A, one end of the sixth resistor R6, one end of a first capacitor C1 and one end of a second capacitor C2, the other end of the second capacitor C2 connected with one end of the first operational amplifier IC1 and one end of the first resistor R3 and the seventh capacitor R3, the other end of the seventh resistor R7 IS connected with the cathode of the first diode D1, the anode of the first diode D1 IS connected with one end of the second resistor R2, the cathode of the second diode D2 and the cathode of the first optical coupler OC1, the other ends of the second resistor R2 and the first resistor R1 are connected with the anode of the first optical coupler OC1, the feedback end IS-1 of the first current detector IS connected with one end of the twelfth resistor R12, the other end of the twelfth resistor R12 IS connected with the inverting input end of the second operational amplifier IC2A, one end of the seventh resistor R7, one end of the fourth capacitor C4 and one end of the fifth capacitor C5, the other end of the fifth capacitor C5 IS connected with one end of the ninth resistor R9, the other ends of the fourth capacitor C4 and the ninth resistor R9 are connected with one end of the eighth resistor R8 and the output end of the second operational amplifier IC2A, the other end of the eighth resistor R8 IS connected with the cathode of the second diode D2 and the sixth resistor R6, the other ends of the third capacitor C3, the sixth capacitor C6, the seventh resistor R7 and the eleventh resistor R11 are grounded.
3. The LED outdoor advertising screen parallel use power supply device according to claim 1, characterized in that: the first set of LEDs is green/blue LEDs.
4. The LED outdoor advertising screen parallel use power supply device according to claim 1, characterized in that: the DC-DC module adopts a voltage reduction DC-DC module, and the second group of LEDs are red LEDs.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202011591275.9A CN112383235B (en) | 2020-12-29 | 2020-12-29 | Power supply device for parallel connection of LED outdoor advertising screens |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011591275.9A CN112383235B (en) | 2020-12-29 | 2020-12-29 | Power supply device for parallel connection of LED outdoor advertising screens |
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| CN112383235A CN112383235A (en) | 2021-02-19 |
| CN112383235B true CN112383235B (en) | 2021-08-20 |
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| CN206058808U (en) * | 2016-08-30 | 2017-03-29 | 中山市积目科技有限公司 | LED module of voltage division power supply |
| CN107612133A (en) * | 2017-10-24 | 2018-01-19 | 长沙捷联飞机维修工程有限公司 | Aviation high-frequency wireless communication system flows redundant power starting with full load system |
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Address after: 423400 floors 1-3, building 7, Jiangbei Industrial Park Innovation and entrepreneurship base (dream pursuit Park), Zixing Economic Development Zone, Chenzhou City, Hunan Province Patentee after: Chenzhou furuikang Electronic Co.,Ltd. Address before: 423400 1st floor, No.7 workshop, Chenzhou Hengfeng Technology Co., Ltd., Hanning West Road, Jiangbei Industrial Park, Zixing Economic Development Zone, Chenzhou City, Hunan Province Patentee before: Chenzhou furuikang Electronic Co.,Ltd. |
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