Patent ID: 12238833

DETAILED DESCRIPTION OF EMBODIMENTS

In order to make the technical problems, the technical solutions and the beneficial effects of the present application be clearer and more understandable, the present application will be further described in detail below with reference to the embodiments. It should be understood that the embodiments described herein are only intended to illustrate but not to limit the present application.

It is worth noting that, when describing that one component is “fixed to” or “arranged on” another component, this component may be directly or indirectly arranged on another component. When describing that one component “is connected with” another component, this component may be directly or indirectly connected to the another component.

It needs to be understood that, directions or location relationships indicated by terms such as “length”, “width”, “up”, “down”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, and so on are the directions or location relationships shown in the accompanying figures, which are only for the purpose of describing the present application conveniently and simplifying the description of the present application, rather than being intended to indicate or imply that an indicated device or component must have specific locations or be constructed and manipulated according to specific locations. Thus, these terms shouldn't be interpreted as limitations to the present application.

In addition, terms of “the first” and “the second” are only used for description purposes, and should not be considered as indicating or implying any relative importance, or implicitly indicating the number of indicated technical features. As such, technical feature(s) restricted by “the first” or “the second” can explicitly or implicitly include one or more of the technical feature(s). In the description of the present application, “a plurality of” has the meaning of two or more, unless additional explicit and specific definition of “a plurality of” is provided.

FIG.1illustrates a schematic structural diagram of an LED control circuit according to one preferable embodiment of the present application. For the convenience of illustration, the part associated with the embodiments of the present application is illustrated merely.

The LED control circuit includes a power terminal VDD, a grounding terminal GND, and a plurality of control signal outputs OUT. The LED control circuit includes a level recognition circuit11and a decoding circuit12.

The level recognition circuit11is connected to the power terminal VDD and the grounding terminal GND of the LED control circuit, and is configured to output a digital signal according to a voltage difference between the voltage at the power terminal VDD and the voltage at the grounding terminal GND.

The decoding circuit12is connected to the level recognition circuit11and a plurality of control signal outputs of the LED control circuit, and is configured to parse the digital signal to obtain control data of the LED control circuit, and output a plurality of control signals to the plurality of control signal outputs OUT according to the control data.

As shown inFIG.2, the LED control circuit further includes a digital filter circuit13.

The digital filter circuit13is connected between the level recognition circuit11and the decoding circuit12, and is configured to perform digital filtering on the digital signal.

The decoding circuit12is specifically configured to parse the digitally filtered digital signal to obtain the control data of the LED control circuit, and output the plurality of control signals to the plurality of control signal outputs according to the control data.

By performing the digital filtering on the digital signal, a bit error rate of the digital signal is reduced, and a stability of the LED control circuit is improved.

It is worth noting that the digital filter circuit13and the decoding circuit12may be reset according to the same reset signal and may be operated according to the same clock signal.

As shown inFIG.3, the plurality of control signal outputs OUTPUT of the LED control circuit are connected to a driving circuit20.

The driving circuit20is configured to output a plurality of driving signals according to the plurality of control signals to enable a plurality of luminescent devices30to emit light.

By way of example rather than limitation, as shown inFIG.4, the level recognition circuit11includes a voltage dividing circuit111, a buck circuit112, and a first comparison circuit113.

The voltage dividing circuit111is connected to the power terminal VDD and the grounding terminal GND of the LED control circuit, and is configured to divide the voltage difference between the voltage at the power terminal VDD and the voltage at the grounding terminal GND to output a first voltage.

The buck circuit112is connected to the power terminal VDD and the grounding terminal GND of the LED control circuit, and is configured to perform a voltage drop of a preset value on the voltage at the power terminal to output a second voltage.

The first comparison circuit113is connected to the decoding circuit12, the voltage dividing circuit111, and the buck circuit112, and is configured to compare the first voltage with the second voltage, and output a digital signal according to a comparison result.

The voltage difference between the voltage at the power terminal VDD and the voltage at the grounding terminal GND is recognized through the voltage dividing circuit111, the buck circuit112and the first comparison circuit113, thus, the reference voltage which serves as the reference signal is not required, a reference circuit for providing the reference voltage is omitted, the circuit is simplified, and the hardware cost is reduced. Moreover, since the voltage dividing circuit may be modulated in a large range, a great voltage difference between the voltage at the power terminal VDD and the voltage at the grounding terminal GND may be adapted, and the application range of the LED control circuit is expanded.

By way of example rather than limitation, as shown inFIG.5, the level recognition circuit11includes a first level shifting circuit114, a second level shifting circuit115, and a second comparison circuit116.

The first level shifting circuit114is connected to the power terminal VDD and the grounding terminal GND of the LED control circuit, and is configured to perform level shifting on the voltage at the grounding terminal GND to output a third voltage.

The second level shifting circuit115is connected to the power terminal VDD and the grounding terminal GND of the LED control circuit, and is configured to perform level shifting on the voltage at the power terminal VDD to output a fourth voltage.

The second comparison circuit116is connected to the decoding circuit12, the first level shifting circuit114, and the second level shifting circuit115, and is configured to compare the third voltage with the fourth voltage and output the digital signal according to the comparison result.

The voltage difference between the voltage at the power terminal and the voltage at the grounding terminal is recognized through the first level shifting circuit114, the second level shifting circuit115, and the second comparison circuit116and thus the digital signal is output. Since the level shifting circuits are realized by utilizing diodes or field-effect transistors, arrangement of resistors are unnecessary. Thus, space occupation of circuit board is reduced.

It should be emphasized that the decoding circuit12may also be powered by the voltage difference between the voltage at the power terminal VDD and the voltage at the grounding terminal GND. As shown inFIG.6, the LED control circuit further includes a shunt circuit14.

The shunt circuit14is connected between the power terminal VDD and the grounding terminal GND, and is configured to shunt a current between the power terminal VDD and the grounding terminal GND.

Since the shunt circuit14shunts the current between the power terminal VDD and the grounding terminal GND, the supply voltage (i.e., the voltage between the power terminal VDD of each LED control circuit and the grounding terminal GND of each LED control circuit) of each of the LED control circuits connected in series is adjusted, ground device can be avoided from being damaged caused due to overvoltage of the supply voltage of the LED control circuit.

FIG.7illustrates an exemplified circuit configuration of a part of the LED control circuit provided in one embodiment of the present application,FIG.8illustrates another exemplified circuit configuration of a part of the LED control circuit,FIG.9illustrates another exemplified circuit configuration of a part of the LED control circuit provided in one embodiment of the present application, andFIG.10shows another partial example circuit structure of the LED control circuit according to one embodiment of the present application. For ease of description, only a part related to the embodiments of the present application is shown, and details are described below:

As shown inFIG.7, the buck circuit112includes a first field-effect transistor M1and a first current source I1.

A source electrode of the first field-effect transistor M1is connected to the power terminal VDD of the LED control circuit, an output of the first current source I1is connected to the grounding terminal GND of the LED control circuit, a drain electrode of the first field-effect transistor M1, a gate electrode of the first field-effect transistor M1, and an input of the first current source I1are used together as a second voltage output of the buck circuit112, is connected to the first comparison circuit113so as to output a second voltage.

The source electrode of the first field-effect transistor M1is connected to the power terminal VDD of the LED control circuit, the drain electrode of the first field-effect transistor M1is connected to the gate electrode of the first field-effect transistor M1, then, the drain electrode of the first field-effect transistor M1and the gate electrode of the first field-effect transistor M1are connected to the comparison circuit113. In this way, performing a voltage drop of the first preset value on the voltage at the power terminal VDD of the LED control circuit is realized.

As shown inFIG.8, the buck circuit112includes a first diode D1and a second current source I2.

A positive electrode of the first diode D1is connected to the power terminal VDD of the LED control circuit, an output of the second current source I2is connected to the grounding terminal GND of the LED control circuit, a negative electrode of the first diode D1and an input of the first current source I1are used together as a second voltage output of the buck circuit112, and are connected to the first comparison circuit113to output the second voltage.

The positive electrode of the first diode D1is connected to the power terminal VDD of the LED control circuit, and the negative electrode of the first diode is connected to the first comparison circuit113. In this way, performing the voltage drop of the first preset value on the voltage at the power terminal VDD of the LED control circuit is realized.

As shown inFIG.7andFIG.8, the voltage dividing circuit111includes a first resistor R1and a second resistor R2.

A first end of the first resistor R1is connected to the power terminal VDD of the LED control circuit, a first end of the second resistor R2is connected to the grounding terminal GND of the LED control circuit, a second terminal of the first resistor R1and a second terminal of the second resistor R2are used together as a first voltage output of the voltage dividing circuit111, and are connected to the first comparison circuit113to output the first voltage.

The voltage dividing circuit111is simple and reliable.

As shown inFIG.7andFIG.8, a non-inverting input of the first comparator U1is used as a second voltage input of the first comparison circuit113, and is connected to the buck circuit112to access the second voltage; the inverting input of the first comparator U1is used as a first voltage input of the first comparison circuit113and is connected to the voltage dividing circuit111to access a first voltage; and an output of the first comparator U1is used as a digital signal output of the first comparison circuit113and is connected to the decoding circuit12to output a digital signal.

The first comparison circuit113is simple and reliable in structure.

As shown inFIG.9, the first level shifting circuit114includes a second field-effect transistor M2and a second current source I2.

A first end of the second current source I2is connected to the power terminal VDD of the LED control circuit, a source electrode of the second field-effect transistor M2is connected to the grounding terminal GND of the LED control circuit, a second end of the second current source I2, a gate electrode of the second field-effect transistor M2, and a drain electrode of the second field-effect transistor M2are used together as a third voltage output of the first level shifting circuit114, and are connected to the second comparison circuit116to output a third voltage.

The source electrode of the second field-effect transistor M2is connected to the grounding terminal GND of the LED control circuit, the gate electrode of the second field-effect transistor M2is connected to the drain electrode of the second field-effect transistor M2, then, the gate electrode of the second field-effect transistor M2and the drain electrode of the second field-effect transistor M2are connected to the second comparison circuit116. In this way, performing an upward level shifting of the second preset value on the voltage at the grounding terminal GND of the LED control circuit is realized.

As shown inFIG.9, the second level shifting circuit115includes a third field-effect transistor M3and a fourth current source I4.

A source electrode of the third field-effect transistor M3is connected to a power terminal VDD of the LED control circuit, an output of the fourth current source I4is connected to the grounding terminal GND of the LED control circuit, a drain electrode of the third field-effect transistor M3, a gate electrode of the third field-effect transistor M3, and an input of the fourth current source I4are used together as a fourth voltage output of the second level shifting circuit115, and are connected to the second comparison circuit116to output a fourth voltage.

The source electrode of the third field-effect transistor M3is connected to the power terminal VDD of the LED control circuit, the drain electrode of the third field-effect transistor M3is connected to the gate electrode of the third field-effect transistor M3, then, they are connected to the second comparison circuit116. In this way, performing a downward level shifting of the third preset value on the voltage at the power terminal VDD of the LED control circuit is realized.

As shown inFIG.10, the first level shifting circuit114includes a second diode D2and a third current source I3.

A first end of the third current source I3is connected to the power terminal VDD of the LED control circuit, a negative electrode of the second diode D2is connected to the grounding terminal GND of the LED control circuit, and a second end of the third current source I3and a positive electrode of the second diode D2are used together as a third voltage output of the first level shifting circuit114, which is connected to the second comparison circuit116to output the third voltage.

The negative electrode of the second diode D2is connected to the grounding terminal GND of the LED control circuit, and the positive electrode of the second diode D2is connected to the second comparison circuit116. In this way, an upward level shifting of a second preset value exerting on the voltage at the grounding terminal GND of the LED control circuit is realized.

As shown inFIG.10, the second level shifting circuit115includes a third diode D3and a fifth current source I5.

A positive electrode of the third diode D3is connected to the power terminal VDD of the LED control circuit, an output of the fifth current source I5is connected to the grounding terminal GND of the LED control circuit, and an negative electrode of the third diode D3and an input of the fifth current source I5are used together as a fourth voltage output of the second level shifting circuit115, which is connected to the second comparison circuit116to output a fourth voltage.

The positive electrode of the third diode D3is connected to the power terminal VDD of the LED control circuit, and the negative electrode of the third diode D3is connected to the second comparison circuit116. In this way, performing a downward level shifting of the third preset value on the voltage at the power terminal VDD of the LED control circuit is realized.

As shown inFIG.9andFIG.10, the second comparison circuit116includes a second comparator U2.

The non-inverting input of the second comparator U2serves as the fourth voltage input of the second comparison circuit116, and is connected to the second level shifting circuit115to access the fourth voltage; an inverting input of the second comparator U2serves as a third voltage input of the second comparison circuit116and is connected to the first level shifting circuit114to access the third voltage. An output of the second comparator U2serves as a digital signal output of the second comparison circuit116and is connected to the decoding circuit12to output the digital signal.

As shown inFIGS.7-10, the driving circuit20includes a fourth field-effect transistor M4, a fifth field-effect transistor M5and a sixth field-effect transistor M6. The shunt circuit14includes a shunt resistor Rs.

What illustrated inFIGS.7-10are further described below with reference to the working principle:

InFIG.7andFIG.8, the first resistor R1and the second resistor R2divide the voltage difference between the voltage at the power terminal VDD and the voltage at the grounding terminal GND to output the first voltage to the inverting input of the comparator U1.

InFIG.7, the field-effect transistor M1performs a voltage drop of a preset value on the voltage at the power terminal VDD to output a second voltage to a non-inverting input of the first comparator U1.

InFIG.8, the diode D1performs a voltage drop of a preset value on the voltage at the power terminal VDD to output a second voltage to the non-inverting input of the first comparator U1.

InFIGS.7and8, the first comparator U1compares the first voltage with the second voltage, and outputs a digital signal according to a comparison result. The digital filter circuit13performs digital filtering on the digital signal. The decoding circuit12parses the digitally filtered digital signal to obtain the control data of the LED control circuit, and outputs the plurality of control signals to the plurality of control signal outputs respectively according to the control data. A gate electrode of the fourth field-effect transistor M4, a gate electrode of the fifth field-effect transistor M5and a gate electrode of the sixth field-effect transistor M6are connected to a plurality of control signals respectively, and a plurality of driving signals are respectively output from a drain electrode of the fourth field-effect transistor M4, a drain electrode of the fifth field-effect transistor M5and a drain electrode of the sixth field-effect transistor M6, thus, a plurality of luminescent devices30(e.g., a light-emitting diode LED1, a light-emitting diode LED2and a light-emitting diode LED3) are enabled to emit light. It should be noted that, the first comparator U1, the digital filter circuit13and the decoding circuit12are powered according to the voltage difference between the voltage at the power terminal VDD and the voltage at the grounding terminal GND. The shunt resistor Rs shunts the current between the power terminal VDD and the grounding terminal GND.

InFIG.9, the second field-effect transistor M2performs level shifting on the voltage at the grounding terminal GND to output the third voltage to the inverting input of the second comparator U2. The third field-effect transistor M3performs level shifting on the voltage at the power terminal VDD to output the fourth voltage to a non-inverting input of the second comparator U2.

InFIG.10, the second diode D2performs level shifting on the voltage at the grounding terminal GND to output the third voltage to the inverting input of the second comparator U2. The third diode D3performs level shifting on the voltage at the power terminal VDD to output the fourth voltage to the non-inverting input of the second comparator U2.

InFIG.9andFIG.10, the second comparator U2compares the third voltage with the fourth voltage, and outputs a digital signal according to a comparison result. The digital filter circuit13performs digital filtering on the digital signal. The decoding circuit12parses the digitally filtered digital signal to obtain the control data of the LED control circuit, and outputs a plurality of control signals to the plurality of control signal outputs according to the control data. The gate electrode of the fourth field-effect transistor M4, the gate electrode of the fifth field-effect transistor M5and the gate electrode of the sixth field-effect transistor M6receive a plurality of control signals, and a plurality of driving signals are output from the drain electrode of the fourth field-effect transistor M4, the drain electrode of the fifth field-effect transistor M5and the drain electrode of the sixth field-effect transistor M6, thus, the plurality of luminescent devices30(e.g., the light-emitting diode LED1, the light-emitting diode LED2and the light-emitting diode LED3) are enabled to emit light. It should be noted that the second comparator U2, the digital filter circuit13and the decoding circuit12are powered according to the voltage difference between the voltage at the power terminal VDD and the voltage at the grounding terminal GND. The shunt resistor Rs shunts the current between the power terminal VDD and the grounding terminal GND.

An electronic apparatus is further provided in the embodiments of the present application. As shown inFIG.11, the electronic apparatus includes a controller100and n LED control circuits10as described above. A power terminal of the first LED control circuit10is connected to a positive electrode of the power supply and a power terminal of the controller100, a grounding terminal of a n-th LED control circuit10is connected to an input of the controller100, a grounding terminal of the i-th LED control circuit10is connected to a power terminal of the (i+1)-th LED control circuit10, and an output of the controller100is connected to a negative electrode of the power supply. The controller100is configured to control an input of the controller100and an output of the controller100to be switched on/off, where N is a natural number greater than 1, and i is a positive integer less than N.

When the controller100controls the input and the output of the controller100to be switched off, the positive electrode of the power supply is connected to the negative electrode of the power supply through the aforesaid n LED control circuits10. In this case, in each LED control circuit10, the first voltage output by the voltage dividing circuit is the voltage at the positive electrode of the power supply, and voltage drop is performed on the second voltage output by the buck circuit experiences for one or multiples times. Thus, the first voltage is greater than the second voltage, and the digital signal is at a low level. When the controller100controls the input and the output of the controller100to be switched on, the positive electrode of the power supply is connected to the negative electrode of the power supply through the aforesaid n LED control circuits10. In this case, in each LED control circuit10, the first voltage output by the voltage dividing circuit is the voltage obtained by dividing the voltage difference between the voltage at the power terminal and the voltage of the grounding terminal, and a voltage drop of a preset value is performed on the voltage at the power terminal according to the second voltage output by the buck circuit. In this case, the first voltage is less than the second voltage, and the digital signal is at a high level. Thus, transmitting instructions via ground wires to realize the control of the LED is realized.

An electronic device is further provided in the embodiments of the present application, as shown inFIG.12, the electronic device includes a DC-DC converter circuit90, a signal transmission circuit80, a first switch circuit60, and m LED control circuits10. A power terminal of the first LED control circuit10is connected to a positive electrode of the power supply, a grounding terminal of the m-th LED control circuit10is connected to an input of the first switch circuit60and an input of the DC-DC converter circuit90, a grounding terminal of the j-th LED control circuit10is connected to a power terminal of the (j+1)-th LED control circuit10, an output of the first switch circuit60is connected to a negative electrode of the power supply and a grounding terminal the DC-DC converter circuit90, and an output of the signal transmission circuit80is connected to a control terminal of the first switch circuit60.

The signal transmission circuit80is configured to output a first control signal. The first switch circuit60is configured to be switched on or switched off according to the first control signal; and the DC-DC converter circuit90is configured to clamp the voltage at the grounding terminal of the m-th LED control circuit when a unidirectional conducting circuit is conducting unidirectionally. Where, m is a natural number greater than 1, and j is a positive integer less than m.

When the first switch circuit60is configured to be switched off according to the first control signal, the DC-DC converter circuit90clamps the voltage at the grounding terminal of the m-th LED control circuit10. Thus, the voltage difference between the voltage at the power terminal and the voltage at the grounding terminal in each LED control circuit10is less than a preset voltage, in this condition, the first voltage output by the voltage dividing circuit is less than the second voltage output by the buck circuit, and the digital signal is at a high level. When the first switch circuit60is configured to be switched on according to the first control signal, the voltage at the grounding terminal of the m-th LED control circuit10is connected to the negative electrode of the power supply. Thus, the voltage difference between the voltage at the power terminal and the voltage of the grounding terminal is greater than the preset voltage in each LED control circuit10. In this condition, the first voltage output by the voltage dividing circuit is greater than the second voltage output by the buck circuit, and the digital signal is at a low level. Thus, transmitting instructions via ground wires to achieve the control of the LED is realized.

When the first switch circuit60is configured to be switched off according to the first control signal, the DC-DC converter circuit90clamps the voltage at the grounding terminal of the m-th LED control circuit10, the voltage difference between the voltage at the power terminal and the voltage at the grounding terminal in each LED control circuit10is less than the preset voltage. In this condition, the third voltage output by the first level shifting circuit is less than the fourth voltage output by the second level shifting circuit, and the digital signal is at a high level. When the first switch circuit60is configured to be switched on according to the first control signal, the voltage at the grounding terminal of the m-th LED control circuit10is connected to the negative electrode of the power supply. Thus, in each LED control circuit10, the voltage difference between the voltage at the power terminal and the voltage at the grounding terminal is greater than the preset voltage. In this condition, the third voltage output by the first level shifting circuit is greater than the fourth voltage output by the second level shifting circuit, and the digital signal is at a low level. Thus, transmitting instructions via ground wires to achieve the control of the LED is realized.

As shown inFIG.13, the electronic device further includes a second switch circuit701.

A grounding terminal of the m-th LED control circuit10is connected to an input of the first switch circuit60and an input of the second switch circuit701, and an output of the second switch circuit701is connected to an input of the DC-DC converter circuit90. The signal transmission circuit80is further configured to output a second control signal. The second switch circuit701is configured to be switched on according to the second control signal to receive the voltage at the grounding terminal of the m-th LED control circuit10, when the first switch circuit60is switched off.

The DC-DC converter circuit90is specifically configured to clamp the voltage at the grounding terminal of the m-th LED control circuit10when the second switch circuit701is switched on.

By providing the second switch circuit701, when the first switch circuit60is configured to be switched on according to the first control signal, the second switch circuit701stops operation, the voltage at the grounding terminal of the m-th LED control circuit10is connected to the negative electrode of the power supply. Thus, the voltage at the grounding terminal of the m-th LED control circuit10is avoided from being connected to the DC-DC converter circuit90, the voltage at the grounding terminal of the m-th LED control circuit10is avoided from being influenced by the DC-DC converter circuit90, the stability and the reliability of the system are improved.

As shown inFIG.14, the electronic device further includes a unidirectional conducting circuit702.

A grounding terminal of the m-th LED control circuit10is connected to an input of the first switch circuit60and an input of the unidirectional conducting circuit702, and an output of the unidirectional conducting circuit702is connected to an input of the DC-DC converter circuit90.

The unidirectional conducting circuit702is configured to enable the voltage at the grounding terminal of the M-th LED control circuit10to be conductive unidirectionally when the first switch circuit60is switched off.

The DC-DC converter circuit90is specifically configured to clamp the voltage at the grounding terminal of the m-th LED control circuit10when the unidirectional conducting circuit702is conducting unidirectionally.

By providing the unidirectional conducting circuit702, when the first switch circuit60is configured to be switched on according to the first control signal, the unidirectional conducting circuit702stops operation, the voltage at the grounding terminal of the m-th LED control circuit10is connected to the negative electrode of the power supply, the voltage at the grounding terminal of the m-th LED control circuit10is prevented from being connected to the DC-DC converter circuit90, the voltage at the grounding terminal of the m-th LED control circuit10is avoided from being influenced by the DC-DC converter circuit90, the stability and the reliability of the system are improved.

When the first switch circuit60is configured to be switched off according to the first control signal, the unidirectional conducting circuit702enables the voltage at the grounding terminal of the M-th LED control circuit10to be conductive unidirectionally, and the DC-DC converter circuit90clamps the voltage at the grounding terminal of the M-th LED control circuit10. Thus, in each LED control circuit10, the voltage difference between the voltage at the power terminal and the voltage at the grounding terminal is less than the preset voltage, in this condition, the first voltage output by the voltage dividing circuit is less than the second voltage output by the buck circuit, and the digital signal is at a high level. When the first switch circuit60is configured to be switched on according to the first control signal, the unidirectional conducting circuit702stops operation, and the voltage at the grounding terminal of the m-th LED control circuit10is connected to the negative electrode of the power supply. Thus, the voltage difference between the voltage at the power terminal and the voltage of the grounding terminal is greater than the preset voltage in each LED control circuit10. In this condition, the first voltage output by the voltage dividing circuit is greater than the second voltage output by the buck circuit, and the digital signal is at a low level. Thus, transmitting instructions via ground wires is implemented and the control of the LED is realized.

When the first switch circuit60is configured to be switched off according to the first control signal, the unidirectional conducting circuit702enables the voltage at the grounding terminal of the M-th LED control circuit10to be unidirectionally conductive, and the DC-DC converter circuit90clamps the voltage at the grounding terminal of the M-th LED control circuit10. Thus, in each LED control circuit10, the voltage difference between the voltage at the power terminal and the voltage at the grounding terminal is less than the preset voltage, in this condition, the third voltage output by the first level shifting circuit is less than the fourth voltage output by the second level shifting circuit, and the digital signal is at a high level. When the first switch circuit60is configured to be switched on according to the first control signal, the unidirectional conducting circuit702stops operation, the voltage at the grounding terminal of the m-th LED control circuit10is connected to the negative electrode of the power supply. Thus, the voltage difference between the voltage at the power terminal and the voltage of the grounding terminal is greater than the preset voltage in each LED control circuit10. In this condition, the third voltage output by the first level shifting circuit is greater than the fourth voltage output by the second level shifting circuit, the digital signal is at a low level. Thus, transmitting instructions via ground wires to achieve the control of the LED is realized.

As shown inFIG.15, the electronic device further includes one or multiple groups of LED control circuits10, where each group of LED control circuits includes m LED control circuits10connected in series.

As shown inFIG.16, the electronic device further includes a protection circuit50.

The protection circuit50is connected between the power terminal of the first LED control circuit10and the grounding terminal of the m-th LED control circuit10, and is configured to filter out a peak signal in a voltage between the power terminal of the first LED control circuit10and the grounding terminal of the m-th LED control circuit10.

It should be noted that the DC-DC converter circuit90is further connected to the signal transmission circuit80, and is further configured to output an internal power supply voltage according to the voltage at the grounding terminal GND of the m-th LED control circuit to supply power to the signal transmission circuit80.

As shown inFIG.17, the DC-DC converter circuit90includes a third resistor R3, a fourth resistor R4, and a first Zener diode Z1. A first end of the third resistor R3serves as a voltage input of the DC-DC converter circuit90, and is connected to the unidirectional conducting circuit70so as to access a voltage at the grounding terminal GND of the m-th LED control circuit. A second end of the third resistor R3, a first terminal of the fourth resistor R4, and a negative electrode of the first Zener diode are used together as an internal supply voltage output of the DC-DC converter circuit90, and are connected to the signal transmission circuit80to output an internal supply voltage. A second end of the fourth resistor R4and a positive electrode of the first Zener diode Z1are connected to a negative electrode of the power supply.

As shown inFIG.17, the signal transmission circuit80includes a microprocessor U3; a power terminal VCC of the microprocessor U3serves as an internal supply voltage input of the signal transmission circuit80and is connected to the DC-DC converter circuit90to access an internal power supply voltage. A first general input/output P1.0of the microprocessor U3serves as a first control signal output of the signal transmission circuit80, is connected to the first switch circuit60to output a first control voltage. A grounding terminal GND of the microprocessor U3is connected to the negative electrode of the power supply.

The first switch circuit60includes a switch transistor Q1, the unidirectional conducting circuit70includes a second diode D4. The protection circuit50includes a second Zener diode Z2.

In the embodiments of the present application, the LED control circuit has the power terminal, the grounding terminal, and the plurality of control signal outputs, and the level recognition circuit outputs the digital signal according to the voltage difference between the voltage at the power terminal and the voltage at the grounding terminal. The decoding circuit parses the digital signal to obtain the control data of the LED control circuit, and outputs the plurality of control signals to the plurality of control signal outputs respectively according to the control data. Since the level recognition circuit outputs the digital signal according to the voltage difference between the voltage at the power terminal and the voltage at the grounding terminal, the level recognition circuit does not need to take the reference voltage as the reference signal. Thus, a reference circuit for providing the reference voltage is omitted, a circuit configuration is simplified and a hardware cost is reduced.

The aforesaid embodiments are only intended to explain the technical solutions of the present application, rather than limiting the technical solutions of the present application. Although the present application has been described in detail with reference to these embodiments, a person of ordinary skilled in the art should understand that, the technical solutions disclosed in the aforesaid embodiments may also be amended, or alternatively, some technical features in the technical solutions may also be equivalently replaced. The amendments or the equivalent replacements don't cause the essence of the corresponding technical solutions to be deviated from the spirit and the scope of the technical solutions in the embodiments of the present application, and thus should all be included in the protection scope of the present application.