CN114783384B - Constant current driving circuit and display device - Google Patents

Constant current driving circuit and display device Download PDF

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Publication number
CN114783384B
CN114783384B CN202210394901.8A CN202210394901A CN114783384B CN 114783384 B CN114783384 B CN 114783384B CN 202210394901 A CN202210394901 A CN 202210394901A CN 114783384 B CN114783384 B CN 114783384B
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China
Prior art keywords
transformer
driving
led channel
module
diode
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CN114783384A (en
Inventor
周建华
李志杰
陈元晟
黄少华
王卫国
胡向峰
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Shenzhen Skyworth RGB Electronics Co Ltd
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Shenzhen Skyworth RGB Electronics Co Ltd
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/3413—Details of control of colour illumination sources
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/345—Current stabilisation; Maintaining constant current

Abstract

The invention discloses a constant current driving circuit and a display device, wherein the constant current driving circuit is applied to driving a plurality of LED channels in an LED channel group, and comprises: LLC module, drive module and power distribution module; the driving module is used for sampling the current of the LED channel through the power distribution module and outputting a driving signal to the LLC module according to the sampling result; the LLC module is electrically connected with the power distribution module and is used for converting the accessed direct current into alternating current according to the driving signal and outputting the alternating current to the power distribution module; the power distribution module is respectively and electrically connected with the LED channels, and is used for switching on or switching off the corresponding LED channels according to alternating current. According to the invention, the power distribution module is arranged, a plurality of constant current circuits in the traditional scheme are omitted, one-stage energy conversion is omitted, and only the LLC module is required to directly convert input current into alternating current and then conduct corresponding LED channels through the power distribution module, so that constant current control is realized.

Description

Constant current driving circuit and display device
Technical Field
The present invention relates to the field of electronic circuits, and in particular, to a constant current driving circuit and a display device.
Background
With the increasing development of display technology, the LED television is developed to be large-screen and high-definition, and the transmittance of screen glass is low, the T-CON power is high, and the module power is increased by about 30% compared with the common product because of the relation of display area and resolution of the current television on the market.
The large display area and high resolution television in the market has larger backlight power, and the LED channels generally adopt 6 channels and 8 channels, wherein the power supply and the constant current system adopt the traditional scheme design, and a plurality of ways of boosting constant current circuits and the like are required to be added, so that the scheme has lower efficiency, higher cost and the like.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: a constant current driving circuit and a display device are provided to solve the problems of low efficiency and high cost of a constant current system.
In order to solve the technical problems, the invention adopts the following technical scheme:
a constant current driving circuit for driving a plurality of LED channels in a LED channel group, the constant current driving circuit comprising: LLC module, drive module and power distribution module;
the driving module is respectively and electrically connected with the LLC module and the power distribution module, and is used for sampling the current of the LED channel through the power distribution module and outputting a driving signal to the LLC module according to a sampling result;
the LLC module is electrically connected with the power distribution module, and is used for converting the accessed direct current into alternating current according to the driving signal and outputting the alternating current to the power distribution module;
the power distribution module is respectively and electrically connected with a plurality of the LED channels, and is used for switching on or switching off the corresponding LED channels according to the alternating current.
Further, the LLC module comprises an LLC unit and a first transformation unit;
the LLC unit is respectively and electrically connected with the driving module and the first transformation unit, and is used for converting the accessed direct current into alternating current according to the driving signal and outputting the alternating current to the first transformation unit;
the first transformation unit is electrically connected with the power distribution module, and is used for transforming the alternating current and outputting the alternating current to the power distribution module.
Further, the LLC unit comprises a first field effect transistor and a second field effect transistor;
the grid electrode of the first field effect tube is connected with the driving module, the drain electrode of the first field effect tube is connected with the direct current, and the source electrode of the first field effect tube is respectively connected with the driving module and the first transformation unit;
the grid electrode of the second field effect tube is connected with the driving module, the drain electrode of the second field effect tube is connected with the source electrode of the first field effect tube, and the source electrode of the second field effect tube is connected with the first transformation unit.
Further, the first transformation unit comprises a first transformer, a second transformer and a first capacitor;
the primary end of the first transformer is connected with the source electrode of the first field effect transistor and the drain electrode of the second field effect transistor respectively, and the secondary end of the first transformer is connected with the power distribution module; one end of the first capacitor is connected with the source electrode of the second field effect transistor, and the other end of the first capacitor is connected with the primary end of the second transformer; the primary end of the second transformer is connected with the primary end of the first transformer in series, the secondary end of the second transformer is connected with the power distribution module, and the secondary end of the first transformer is connected with the secondary end of the second transformer in series.
Further, the LED channel group includes a first LED channel and a second LED channel, each of the first LED channel and the second LED channel is connected in series with an LED lamp bead, and the power distribution module includes a second capacitor, a first diode, a second diode, a third diode and a fourth diode;
one end of the second capacitor is connected with the secondary end of the first transformer, and the other end of the second capacitor is connected with the positive electrode of the first diode;
the cathode of the first diode is connected with the input end of the first LED channel, and the output end of the first LED channel is grounded;
the anode of the second diode is grounded, and the cathode of the second diode is respectively connected with the other end of the first capacitor and the anode of the first diode;
the anode of the third diode is connected with the secondary end of the second transformer, the cathode of the third diode is connected with the input end of the second LED channel, and the output end of the third diode is grounded;
the positive electrode of the fourth diode is grounded, and the negative electrode of the fourth diode is respectively connected with the secondary end of the second transformer and the positive electrode of the third diode.
Further, the LED channel group further comprises a third LED channel and a fourth LED channel;
the input end of the third LED channel is connected with the output end of the first LED channel and grounded, and the output end of the third LED channel is connected with the anode of the second diode;
the input end of the fourth LED channel is connected with the output end of the second LED channel and grounded, and the output end of the fourth LED channel is connected with the anode of the fourth diode.
Further, the driving module comprises a driving unit, a second transformation unit and a sampling unit;
the sampling unit is respectively and electrically connected with the power distribution module and the driving unit, and is used for sampling the current of the LED channel and outputting a corresponding sampling signal to the driving unit;
the driving unit is electrically connected with the second transformation unit and is used for outputting the driving signal to the second transformation unit according to the sampling signal;
the second transformation unit is electrically connected with the LLC unit respectively, and the second transformation unit is used for transforming the driving signals and outputting the driving signals to the LLC unit.
Further, the sampling unit comprises a sampling resistor, one end of the sampling resistor is respectively connected with the LED channel and the driving unit, and the other end of the sampling resistor is grounded.
Further, the second transformation unit comprises a third transformer and a third capacitor;
the first pin of the third transformer is respectively connected with the source electrode of the first field effect tube, the drain electrode of the second field effect tube and the primary end of the first transformer, the second pin of the third transformer is connected with the grid electrode of the first field effect tube, the fourth pin of the third transformer is connected with the grid electrode of the second field effect tube, the fifth pin of the third transformer is respectively connected with the source electrode of the second field effect tube and one end of the first capacitor, the seventh pin of the third transformer is connected with the driving unit, the ninth pin of the third transformer is connected with one end of the third capacitor, and the other end of the third capacitor is connected with the driving unit.
A display device comprising the constant current drive circuit according to any one of the above and an LED channel group, the constant current drive circuit being electrically connected to the LED channel group.
The invention has the beneficial effects that: by arranging the power distribution module and canceling a plurality of boosting constant current circuits in the traditional constant current driving circuit, one-stage energy conversion is omitted, only the LLC module is required to directly convert input current into alternating current and then input the alternating current into an LED channel group at the rear end, and the corresponding LED channels are conducted through the power distribution module so as to realize constant current control of multiple paths of LED channels, thereby improving efficiency, reducing cost and optimizing circuit structure.
Drawings
Fig. 1 is a circuit schematic block diagram of a constant current drive circuit of the prior art;
FIG. 2 is a schematic circuit diagram of a first transformer unit of the prior art;
fig. 3 is a circuit schematic block diagram of a constant current drive circuit of an embodiment of the present invention;
fig. 4 is a schematic circuit diagram of a constant current driving circuit according to an embodiment of the present invention;
FIG. 5 is another schematic circuit diagram of a constant current driving circuit according to an embodiment of the present invention;
fig. 6 is a schematic circuit diagram of the first transformer unit of the present invention.
Description of the reference numerals: 100. an LLC module; 110. an LLC unit; 120. a first transformation unit; 200. a driving module; 210. a sampling unit; 220. a driving unit; 230. a second transformation unit; 300. a power distribution module; 400. an LED channel group; 410. a first LED channel; 420. a second LED channel; 430. a third LED channel; 440. and a fourth LED channel.
Detailed Description
In order to describe the technical contents, the achieved objects and effects of the present invention in detail, the following description will be made with reference to the embodiments in conjunction with the accompanying drawings.
Examples
Referring to fig. 1, in a constant current driving circuit in the prior art, an LLC circuit boosts an input current and converts the boosted input current into a fixed voltage, and then realizes constant current through a constant current circuit, requiring two stages of energy conversion; in addition, each path of LED channel is required to be matched with a constant current circuit and corresponding electric components, so that the constant current driving circuit in the prior art has the advantages of higher cost, lower efficiency and more complex circuit structure.
Referring to fig. 3 to 6, an embodiment of the present invention is as follows:
a constant current driving circuit is applied to driving display devices such as an LED display screen, an LED touch screen and an LED all-in-one machine to display pictures.
Referring to fig. 3, the constant current driving circuit is electrically connected to the LED channel group 400, and the LED channel group 400 includes a plurality of LED channels; the constant current drive circuit includes: an LLC module 100, a drive module 200, and a power distribution module 300; the driving module 200 is electrically connected to the LLC module 100 and the power distribution module 300, respectively, and the driving module 200 is configured to sample the current of the LED channel through the power distribution module 300, and output a driving signal to the LLC module 100 according to the sampling result; the LLC module 100 is electrically connected to the power distribution module 300, and the LLC module 100 is configured to convert the accessed dc power into ac power according to the driving signal, and output the ac power to the power distribution module 300; the power distribution module 300 is electrically connected to the LED channels, and the power distribution module 300 is configured to turn on or off the corresponding LED channels according to the alternating current.
The working principle of the constant current driving circuit in this embodiment is as follows: after the power supply is connected with high-voltage alternating current, the high-voltage direct current is output after filtering and rectifying, the LLC module 100 is connected with the high-voltage direct current, the driving module 200 samples the current of the LED channels and outputs the driving signal to the LLC module 100, the LLC module 100 converts the direct current into alternating current according to the driving signal and outputs the alternating current to the power distribution module 300, and the power distribution module 300 conducts the corresponding LED channels according to the alternating current so as to light or extinguish the corresponding LED lamp beads.
It can be understood that the constant current driving circuit in this embodiment sets the power distribution module 300, and cancels a plurality of boosting constant current circuits in the conventional constant current system, omits one-stage energy conversion, and only needs the LLC module 100 to directly convert the input current into the alternating current and then inputs the alternating current into the LED channel group 400 at the rear end, and conducts the corresponding LED channels through the power distribution module 300, so as to realize multi-channel constant current control, thereby improving efficiency, reducing cost, and optimizing circuit structure.
In this embodiment, the LLC module 100 includes an LLC unit 110 and a first transforming unit 120; the LLC unit 110 is electrically connected to the driving module 200 and the first transforming unit 120, and the LLC unit 110 is configured to convert the accessed dc into ac according to the driving signal and output the ac to the first transforming unit 120; the first transforming unit 120 is electrically connected to the power distribution module 300, and the first transforming unit 120 is configured to transform the alternating current and output the alternating current to the power distribution module 300.
It can be appreciated that, in this embodiment, the LLC unit 110 converts the connected direct current into alternating current according to the driving signal, and outputs the alternating current to the first transforming unit 120, and the first transforming unit 120 steps down the alternating current to the power supply voltage required by the LED lamp beads, and conducts the corresponding LED channels through the power distribution module 300.
Referring to fig. 4, specifically, the LLC unit 110 includes a first fet Q1 and a second fet Q2; the grid electrode of the first field effect transistor Q1 is connected with the driving module 200, the drain electrode of the first field effect transistor Q1 is connected with the direct current HV_DC, and the source electrode of the first field effect transistor Q1 is respectively connected with the driving module 200 and the first transformation unit 120; the gate of the second fet Q2 is connected to the driving module 200, the drain of the second fet Q2 is connected to the source of the first fet Q1, and the source of the second fet Q2 is connected to the first transformer unit 120. In this embodiment, when the driving signal is at a high level, the first field effect transistor Q1 is turned on, and the second field effect transistor Q2 is turned off; when the driving signal is at a low level, the first fet Q1 is turned off and the second fet Q2 is turned on.
Further, the first transforming unit 120 includes a first transformer T1, a second transformer T2, and a first capacitor C1; the primary end of the first transformer T1 is connected to the source electrode of the first field effect transistor Q1 and the drain electrode of the second field effect transistor Q2, respectively, and the secondary end of the first transformer T1 is connected to the power distribution module 300; one end of the first capacitor C1 is connected with the source electrode of the second field effect transistor Q2, and the other end of the first capacitor C1 is connected with the primary end of the second transformer T2; the primary side of the second transformer T2 is connected in series with the primary side of the first transformer T1, and the secondary side of the second transformer T2 is connected to the power distribution module 300.
In this embodiment, when the driving signal is at a high level, the first fet Q1 is turned on, the second fet Q2 is turned off, the direct current hv_dc supplies power to the first transformer T1, the second transformer T2 and the first capacitor C1 through the first field effect, and the secondary end of the first transformer T1 and the secondary end of the second transformer T2 are output to the power distribution module 300 to light the corresponding LED channels. When the driving signal is at a low level, the first fet Q1 is turned off, the second fet Q2 is turned on, the first transformer T1, the second transformer T2, the first capacitor C1, and the second fet Q2 form a playback circuit, and output currents to the power distribution module 300 through the secondary side of the first transformer T1 and the secondary side of the second transformer T2 to light the corresponding LED channels.
Referring to fig. 2, in order to increase the power, the prior art adopts a dual-transformer primary series and secondary parallel manner to increase the output power. Since the secondary side outputs are in parallel, V out ＝V s1 ＝V s2 . And primary ends are connected in series, so V in ＝V p1 +V p2 . The ratio of the turns of the transformer is the ratio of the primary turns to the secondary turns, which is also equivalent to the ratio of the primary voltage to the secondary voltage, i.e(the turns ratio of the transformer is n) so that +.>By way of example, two transformers of identical design are chosen, available->ThenI.e. < ->
Therefore, the mode of connecting the primary ends of the double transformers in series and connecting the secondary ends in parallel is adopted to increase the output power, but more secondary end coil numbers are needed under high-voltage output, so that the transformer is not suitable for a thin type transformer, and the internal occupied space of circuit components is not reduced.
Referring to fig. 6, in the present embodiment, the secondary side of the first transformer T1 is connected in series with the secondary side of the second transformer T2 to obtain V out ＝V s1 +V s2 ，V in ＝V p1 +V p2 . According to the formula of the turn ratio of the transformerIt is known that the number of the components,for example, the first transformer T1 and the second transformer T2 are transformers of the same type and specification>Further toIs characterized in that,
i.e. < ->
Therefore, by connecting the primary ends and the secondary ends of the two transformers in series, under the condition that the number ratio of the single transformer is unchanged, compared with the connection mode in the prior art, the output voltage is improved by two times, the occupied space of circuit components is reduced while the power is improved, and the circuit structure is optimized.
Referring to fig. 4, in the present embodiment, the LED channel group 400 includes a first LED channel 410 and a second LED channel 420, the first LED channel 410 and the second LED channel 420 are respectively connected in series with LED lamp beads, and the power distribution module 300 includes a second capacitor C2, a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4; one end of the second capacitor C2 is connected with the secondary end of the first transformer T1, and the other end of the second capacitor C2 is connected with the anode of the first diode D1; the negative electrode of the first diode D1 is connected with the input end of the first LED channel 410, and the output end of the first LED channel 410 is grounded; the positive electrode of the second diode D2 is grounded, and the negative electrode of the second diode D2 is respectively connected with the other end of the first capacitor C1 and the positive electrode of the first diode D1; the positive electrode of the third diode D3 is connected to the secondary end of the second transformer T2, the negative electrode of the third diode D3 is connected to the input end of the second LED channel 420, and the output end of the third diode D3 is grounded; the positive electrode of the fourth diode D4 is grounded, and the negative electrode of the fourth diode D4 is connected to the secondary end of the second transformer T2 and the positive electrode of the third diode D3, respectively.
In this embodiment, when the driving signal is at a high level, the first field effect transistor Q1 is turned on, the second field effect transistor Q2 is turned off, the direct current hv_dc supplies power to the first transformer T1, the second transformer T2 and the first capacitor C1 through the first field effect, the secondary side of the first transformer T1 and the secondary side of the second transformer T2 output currents to the first diode D1 and the third diode D3, and the first LED channel 410 is turned on after passing through the first diode D1 and the second LED channel 420 is turned on after passing through the third diode D3. When the driving signal is at a low level, the first fet Q1 is turned off, the second fet Q2 is turned on, the first transformer T1, the second transformer T2, the first capacitor C1, and the second fet Q2 form a playback circuit, but no LED channel can flow through in a current loop formed by the secondary side of the first transformer T1 and the secondary side of the second transformer T2, and the first LED channel 410 and the second LED channel 420 are not turned on.
Referring to fig. 5, the present embodiment further discloses another circuit structure of the constant current driving circuit, and further, the LED channel group 400 further includes a third LED channel 430 and a fourth LED channel 440; the input end of the third LED channel 430 is connected to the output end of the first LED channel 410 and to the ground, and the output end of the third LED channel 430 is connected to the anode of the second diode D2; the input end of the fourth LED channel 440 is connected to the output end of the second LED channel 420 and to the ground, and the output end of the fourth LED channel 440 is connected to the anode of the fourth diode D4.
Specifically, when the driving signal is at a high level, the first field effect transistor Q1 is turned on, the second field effect transistor Q2 is turned off, the direct current hv_dc supplies power to the first transformer T1, the second transformer T2 and the first capacitor C1 through the first field effect, the secondary side of the first transformer T1 and the secondary side of the second transformer T2 output currents to the first diode D1 and the third diode D3, the first LED channel 410 is turned on after passing through the first diode D1, the second LED channel 420 is turned on after passing through the third diode D3, the second diode D2 and the fourth diode D4 are turned off, and no current passes through the third LED channel 430 and the fourth LED channel 440. When the driving signal is at a low level, the first fet Q1 is turned off, the second fet Q2 is turned on, the first transformer T1, the second transformer T2, the first capacitor C1, and the second fet Q2 form a playback circuit, the secondary side of the first transformer T1 and the secondary side of the second transformer T2 output playback currents to the second diode D2 and the fourth diode D4, the third LED channel 430 is turned on after passing through the second diode D2, the fourth LED channel 440 is turned on after passing through the fourth diode D4, the first diode D1 and the third diode D3 are turned off, and the first LED channel 410 and the second LED channel 420 have no current passing through.
In this embodiment, the driving signal of the driving module 200 sequentially turns on and off the first field effect transistor Q1 and the second field effect transistor Q2, converts the high-voltage direct current hv_dc into square wave current with high and low levels, drives the first transformer T1, the second transformer T2 and the first capacitor C1 to realize energy conversion, and simultaneously realizes energy distribution of each LED channel through each diode of the power distribution module 300. Further, the 2-channel constant current driving circuit and the 4-channel constant current driving circuit in the embodiment are combined, so that constant current control can be performed on the 6-channel and 8-channel LED televisions.
Further, the driving module 200 includes a driving unit 220, a second transforming unit 230, and a sampling unit 210; the sampling unit 210 is electrically connected to the power distribution module 300 and the driving unit 220, respectively, and the sampling unit 210 is configured to sample the current of the LED channel and output a corresponding sampling signal ISEN to the driving unit 220; the driving unit 220 is electrically connected to the second transforming unit 230, and the driving unit 220 is configured to output the driving signal to the second transforming unit 230 according to the sampling signal ISEN; the second transforming units 230 are electrically connected to the LLC units 110, respectively, and the second transforming units 230 are configured to transform the driving signals and output the driving signals to the LLC units 110. The driving unit 220 includes a driving chip, and the driving chip is configured to output a corresponding driving signal to the voltage transformation module according to the sampling signal ISEN, and control the output voltage of the first voltage transformation unit 120 by adjusting the on and off frequencies and the duty ratios of the first field effect transistor Q1 and the second field effect transistor Q2, so as to realize constant current control on a plurality of paths of LED channels. The driving chip is also connected with an external main board, receives an enabling signal and a dimming signal output by the main board, and is controlled by the main board.
Specifically, the sampling unit 210 includes a sampling resistor R1, one end of the sampling resistor R1 is connected to the LED channel and the driving unit 220, and the other end of the sampling resistor R1 is grounded.
Specifically, the second transforming unit 230 includes a third transformer T3 and a third capacitor C3; the first pin of the third transformer T3 is connected with the source electrode of the first field effect transistor Q1, the drain electrode of the second field effect transistor Q2 and the primary end of the first transformer T1, the second pin of the third transformer T3 is connected with the gate electrode of the first field effect transistor Q1, the fourth pin of the third transformer T3 is connected with the gate electrode of the second field effect transistor Q2, the fifth pin of the third transformer T3 is connected with the source electrode of the second field effect transistor Q2 and one end of the first capacitor C1, the seventh pin of the third transformer T3 is connected with the driving unit 220, the ninth pin of the third transformer T3 is connected with one end of the third capacitor C3, and the other end of the third capacitor C3 is connected with the driving unit 220. It can be understood that the primary side of the third transformer T3 is connected to the driving chip, and the first fet Q1 is controlled by an upper coil of the secondary side of the third transformer T3 and the second fet Q2 is controlled by a lower coil of the secondary side of the third transformer T3 according to the driving signal output from the driving chip.
The embodiment also discloses a display device, which comprises the constant current driving circuit and the LED channel group, wherein the constant current driving circuit is electrically connected with the LED channel to drive the LED lamp beads on the LED channel group to light up, so that the display device displays pictures.
In summary, according to the constant current driving circuit and the display device provided by the invention, the power distribution module is arranged, a plurality of boosting constant current circuits in the traditional constant current driving circuit are omitted, one-stage energy conversion is omitted, only the LLC module is required to directly convert input current into alternating current and then input the alternating current into the LED channel group at the rear end, and the corresponding LED channels are conducted through the power distribution module, so that constant current control of multiple paths of LED channels is realized, and therefore, the efficiency is improved, the cost is reduced, and the circuit structure is optimized. Besides, the double transformers are adopted, the primary ends of the two transformers are connected in series, and the secondary ends of the two transformers are connected in series, so that under the condition of the same turn ratio, the output voltage is improved to be twice of the original output voltage, and the occupied space of components in the constant current drive circuit is favorably optimized.
The foregoing description is only illustrative of the present invention and is not intended to limit the scope of the invention, and all equivalent changes made by the specification and drawings of the present invention, or direct or indirect application in the relevant technical field, are included in the scope of the present invention.

Claims (7)

1. A constant current driving circuit applied to driving a plurality of LED channels in an LED channel group, the constant current driving circuit comprising: LLC module, drive module and power distribution module;
the driving module is respectively and electrically connected with the LLC module and the power distribution module, and is used for sampling the current of the LED channel through the power distribution module and outputting a driving signal to the LLC module according to a sampling result;
the LLC module is electrically connected with the power distribution module, and is used for converting the accessed direct current into alternating current according to the driving signal and outputting the alternating current to the power distribution module;
the power distribution module is respectively and electrically connected with a plurality of the LED channels and is used for switching on or switching off the corresponding LED channels according to the alternating current;
the LLC module comprises an LLC unit and a first transformation unit, and the LLC unit comprises a first field effect transistor and a second field effect transistor;
the LLC unit is respectively and electrically connected with the driving module and the first transformation unit, and is used for converting the accessed direct current into alternating current according to the driving signal and outputting the alternating current to the first transformation unit;
the first transformation unit is electrically connected with the power distribution module and is used for transforming the alternating current and outputting the alternating current to the power distribution module;
the first transformation unit comprises a first transformer, a second transformer and a first capacitor;
the primary end of the first transformer is connected with the source electrode of the first field effect transistor and the drain electrode of the second field effect transistor respectively, and the secondary end of the first transformer is connected with the power distribution module; one end of the first capacitor is connected with the source electrode of the second field effect transistor, and the other end of the first capacitor is connected with the primary end of the second transformer; the primary end of the second transformer is connected with the primary end of the first transformer in series, the secondary end of the second transformer is connected with the power distribution module, and the secondary end of the first transformer is connected with the secondary end of the second transformer in series;
the LED channel group comprises a first LED channel and a second LED channel, LED lamp beads are respectively connected in series with the first LED channel and the second LED channel, and the power distribution module comprises a second capacitor, a first diode, a second diode, a third diode and a fourth diode;
one end of the second capacitor is connected with the secondary end of the first transformer, and the other end of the second capacitor is connected with the positive electrode of the first diode;
the cathode of the first diode is connected with the input end of the first LED channel, and the output end of the first LED channel is grounded;
the anode of the second diode is grounded, and the cathode of the second diode is respectively connected with the other end of the first capacitor and the anode of the first diode;
the anode of the third diode is connected with the secondary end of the second transformer, the cathode of the third diode is connected with the input end of the second LED channel, and the output end of the third diode is grounded;
the positive electrode of the fourth diode is grounded, and the negative electrode of the fourth diode is respectively connected with the secondary end of the second transformer and the positive electrode of the third diode.
2. The constant current driving circuit according to claim 1, wherein a gate of the first field effect transistor is connected to the driving module, a drain of the first field effect transistor is connected to the direct current, and a source of the first field effect transistor is connected to the driving module and the first transforming unit, respectively;
the grid electrode of the second field effect tube is connected with the driving module, the drain electrode of the second field effect tube is connected with the source electrode of the first field effect tube, and the source electrode of the second field effect tube is connected with the first transformation unit.
3. The constant current drive circuit according to claim 1, wherein the LED channel group further includes a third LED channel and a fourth LED channel;
the input end of the third LED channel is connected with the output end of the first LED channel and grounded, and the output end of the third LED channel is connected with the anode of the second diode;
the input end of the fourth LED channel is connected with the output end of the second LED channel and grounded, and the output end of the fourth LED channel is connected with the anode of the fourth diode.
4. The constant current driving circuit according to claim 1, wherein the driving module includes a driving unit, a second transforming unit, and a sampling unit;
the sampling unit is respectively and electrically connected with the power distribution module and the driving unit, and is used for sampling the current of the LED channel and outputting a corresponding sampling signal to the driving unit;
the driving unit is electrically connected with the second transformation unit and is used for outputting the driving signal to the second transformation unit according to the sampling signal;
the second transformation unit is electrically connected with the LLC unit respectively, and the second transformation unit is used for transforming the driving signals and outputting the driving signals to the LLC unit.
5. The constant current driving circuit according to claim 4, wherein the sampling unit comprises a sampling resistor, one end of the sampling resistor is respectively connected with the LED channel and the driving unit, and the other end of the sampling resistor is grounded.
6. The constant current driving circuit according to claim 4, wherein the second transforming unit includes a third transformer and a third capacitor;
the first pin of the third transformer is respectively connected with the source electrode of the first field effect tube, the drain electrode of the second field effect tube and the primary end of the first transformer, the second pin of the third transformer is connected with the grid electrode of the first field effect tube, the fourth pin of the third transformer is connected with the grid electrode of the second field effect tube, the fifth pin of the third transformer is respectively connected with the source electrode of the second field effect tube and one end of the first capacitor, the seventh pin of the third transformer is connected with the driving unit, the ninth pin of the third transformer is connected with one end of the third capacitor, and the other end of the third capacitor is connected with the driving unit.
7. A display device comprising the constant current drive circuit according to any one of claims 1 to 6 and an LED channel group, the constant current drive circuit being electrically connected to the LED channel group.
CN202210394901.8A 2022-04-15 2022-04-15 Constant current driving circuit and display device Active CN114783384B (en)

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Publication number Priority date Publication date Assignee Title
CN104254172A (en) * 2013-06-28 2014-12-31 三星电机株式会社 Light emitting diode power supply apparatus
CN104935843A (en) * 2015-06-16 2015-09-23 康佳集团股份有限公司 LED (Light-Emitting Diode) television two-in-one power supply circuit and LED television
CN110769173A (en) * 2019-10-18 2020-02-07 深圳创维－Rgb电子有限公司 Television power supply system and television
CN213073182U (en) * 2020-09-28 2021-04-27 深圳创维－Rgb电子有限公司 LED control circuit and display device

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Publication number Priority date Publication date Assignee Title
KR20130003254A (en) * 2011-06-30 2013-01-09 엘지이노텍 주식회사 Apparatus for reducing standby power consumption

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Publication number Priority date Publication date Assignee Title
CN104254172A (en) * 2013-06-28 2014-12-31 三星电机株式会社 Light emitting diode power supply apparatus
CN104935843A (en) * 2015-06-16 2015-09-23 康佳集团股份有限公司 LED (Light-Emitting Diode) television two-in-one power supply circuit and LED television
CN110769173A (en) * 2019-10-18 2020-02-07 深圳创维－Rgb电子有限公司 Television power supply system and television
CN213073182U (en) * 2020-09-28 2021-04-27 深圳创维－Rgb电子有限公司 LED control circuit and display device

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