CN216014779U

CN216014779U - Display screen constant current power supply circuit, display screen and washing machine

Info

Publication number: CN216014779U
Application number: CN202122432582.9U
Authority: CN
Inventors: 崔增良
Original assignee: Hisense Shandong Refrigerator Co Ltd
Current assignee: Hisense Refrigerator Co Ltd
Priority date: 2021-10-09
Filing date: 2021-10-09
Publication date: 2022-03-11
Anticipated expiration: 2031-10-09

Abstract

The application provides a display screen constant current power supply circuit, a display screen and a washing machine. The display screen constant current power supply circuit at least comprises a power supply input circuit, a transformer, a feedback circuit and a constant current control circuit. The primary winding of the transformer is electrically connected with the power input circuit; the transformer is also provided with a first secondary winding and a second secondary winding; the constant current control circuit comprises a first control end, a second control end, a third control end and a constant current output end; the constant current control circuit and the first secondary winding form a voltage control loop; the constant current control circuit and the second secondary winding form a current control loop; the output current of the constant current output end is constant so as to supply power to the display screen. The display screen constant current power supply circuit improves the stability of the brightness of the display screen by providing constant current.

Description

Display screen constant current power supply circuit, display screen and washing machine

Technical Field

The application relates to the technical field of washing machines, in particular to a display screen constant-current power supply circuit, a display screen and a washing machine.

Background

At present, the functions of the washing machine are more and more abundant. The display screen design of the washing machine also shows a diversified trend for the interactive needs.

The display screen is usually provided with a plurality of LED lamp beads for displaying information such as operation function and timing. If the number of the lighted LED beads changes, the brightness of the display screen will also change, which is schematically illustrated in the figure, if the display screen has a plurality of display partitions, the load will change when each display partition is lighted, and the display brightness will also change accordingly.

The above information disclosed in this background section is only for enhancement of understanding of the background of the application and therefore it may contain information that does not constitute prior art that is already known to a person of ordinary skill in the art.

SUMMERY OF THE UTILITY MODEL

An object of this application lies in improving the display screen constant current supply circuit that can promote the stability of display screen luminance.

Another object of the present application is to provide a display screen having stable luminance.

It is still another object of the present application to provide a washing machine having a display screen with stable brightness.

In order to solve the technical problem, the following technical scheme is adopted in the application:

according to one aspect of the application, a display screen constant current supply circuit is provided, and the circuit comprises:

the power input circuit is connected to the mains supply;

the input end of the primary winding of the transformer is electrically connected with the output end of the power input circuit; the transformer is also provided with a first secondary winding and a second secondary winding;

the feedback circuit is connected between the second secondary winding and the power input circuit and is used for generating a feedback signal to the power input circuit;

the constant current control circuit comprises a first control end, a second control end, a third control end and a constant current output end; one end of the first secondary winding is connected with the first control end, and the other end of the first secondary winding is connected with the third control end, so that the constant current control circuit and the first secondary winding form a voltage control loop; one end of the second secondary winding is connected with the second control end, and the other end of the second secondary winding is connected with the third control end, so that the constant current control circuit and the second secondary winding form a current control loop; the output current of the constant current output end is constant so as to supply power to the display screen.

In some embodiments, the secondary winding of the transformer has a first end, a second end, and a common end; the winding between the first end and the common end forms a first secondary winding; the winding between the second end and the common end forms a second secondary winding; the common end is located on the same side of the first end as the second end.

In some embodiments, the common terminal is electrically connected to the third control terminal; the first end is electrically connected with the first control end; the second end is electrically connected with the second control end;

the constant current control circuit is also provided with a first operational amplifier, a second operational amplifier and a reference voltage;

the output end of the first control end and the output end of the reference voltage are respectively and electrically connected with two input ends of the first operational amplifier so as to input the output voltage of the first end and the reference voltage to the first operational amplifier; the second control end and the third control end are respectively and electrically connected with two input ends of the second operational amplifier so as to input output signals of the second end and the common end to the second operational amplifier; the first operational amplifier and the second operational amplifier have a common output terminal, and the common output terminal is a constant current output terminal.

In some embodiments, the feedback circuit includes a first diode and a first triode; the constant current output end is electrically connected with the anode of the first diode, and the cathode of the first diode is grounded; the emitter of the first triode is grounded, and the collector of the first triode is electrically connected with the power input circuit; when the output signal of the constant current output end changes, the light emitted by the first diode changes, so that the collector current of the first triode changes, and a feedback signal is generated and input to the power input circuit.

In some embodiments, the power input circuit includes a voltage control chip; the voltage control chip is provided with a feedback signal input end and a driving signal output end; the feedback signal input end is electrically connected with the output end of the feedback circuit; the driving signal output end is electrically connected with the primary coil of the transformer so as to adjust the driving signal output to the primary coil according to the feedback signal.

In some embodiments, the power input circuit further comprises a switching device; the switch device is provided with a first pin, a second pin and a control pin; the first pin is connected to the primary winding; the second pin is grounded, the input end of the control pin is electrically connected with the driving signal output end to receive a driving signal, and the driving signal is used for controlling the connection or disconnection of the first pin and the second pin.

In some embodiments, the power input circuit further comprises a power interface, a filter circuit, and a rectifier circuit; the power interface is used for connecting commercial power; the input end of the filter circuit is electrically connected with the output end of the power interface, and the output end of the filter circuit is electrically connected with the input end of the rectifying circuit; the output end of the rectifying circuit is electrically connected with the primary winding of the transformer and the voltage control chip so as to output an electric signal required by the primary winding of the transformer under the control of the voltage control chip.

In some embodiments, the constant current control circuit includes a constant current control chip.

According to another aspect of the application, a display screen is also provided, and comprises a first display subarea and a second display subarea; the display screen is powered by the display screen constant-current power supply circuit, and the output current of the display screen constant-current power supply circuit is constant under the condition that the first display subarea and/or the second display subarea are/is lightened.

According to another aspect of the present application, there is also provided a washing machine including: the display screen comprises a first display subarea and a second display subarea; according to the display screen constant current power supply circuit, the display screen constant current power supply circuit is used for supplying power to the display screen, and the output current of the display screen constant current power supply circuit is constant under the condition that the first display subarea and/or the second display subarea are/is lightened.

According to the technical scheme, the beneficial effects of the application are as follows:

in the application, a voltage control loop is formed by the first secondary winding and the constant current control circuit to control the value of the output voltage of the constant current control circuit; the current control loop is formed by the second secondary winding and the constant current control circuit, and the output current of the constant current control circuit is limited, so that the constant current output of the display screen interface is realized, the stability of the output current is ensured, the conversion of the commercial power to the constant current power supply of the display screen is realized, the brightness stability of the display screen is improved, and the display screen has good market application value.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The above and other objects, features and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

Fig. 1 is a block diagram illustrating a structure of a constant current power supply circuit for a display panel according to an exemplary embodiment;

FIG. 2 is a circuit diagram of a secondary side of a transformer, shown in accordance with an exemplary embodiment;

fig. 3 is a schematic diagram showing an internal structure of a constant current control chip according to still another exemplary embodiment;

fig. 4 is a circuit diagram illustrating a primary side of a transformer according to an example embodiment.

Detailed Description

While this application is susceptible of embodiment in different forms, there is shown in the drawings and will herein be described in detail only some specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the application and is not intended to limit the application to that as illustrated herein.

Thus, a feature indicated in this specification is intended to describe one of the features of an embodiment of the application and does not imply that every embodiment of the application must have the described feature. Further, it should be noted that this specification describes many features. Although some features may be combined to show a possible system design, these features may also be used in other combinations not explicitly described. Thus, the combinations illustrated are not intended to be limiting unless otherwise specified.

In the embodiments shown in the drawings, directional references (such as up, down, left, right, front, and rear) are used to explain the structure and movement of the various elements of the present application not absolutely, but relatively. These descriptions are appropriate when the elements are in the positions shown in the drawings. If the description of the positions of these elements changes, the indication of these directions changes accordingly.

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The drawings are merely schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repetitive description will be omitted.

The preferred embodiments of the present application will be further described in detail below with reference to the accompanying drawings of the present specification.

Fig. 1 is a block diagram illustrating a structure of a constant current power supply circuit for a display panel according to an example embodiment. As shown in fig. 1, the display panel constant current power supply circuit at least includes a power input circuit 110, a transformer 120, a constant current control circuit 130, and a feedback circuit 140.

The input end of the power input circuit 110 is connected to the mains supply, and the input end may be a mains supply interface. The power input circuit 110 is used for processing the commercial power and outputting the voltage required by the secondary side of the transformer 120.

The input end of the primary winding of the transformer 120 is electrically connected with the output end of the power input circuit 110 to receive the processed voltage of the power input circuit 110; the transformer 120 also has a first secondary winding and a second secondary winding. It should be noted that the number of winding turns of the first secondary winding and the second secondary winding is calculated, and the number of winding turns satisfies the secondary power demand. The voltage required by the display screen and the voltage required by the constant current control circuit 130 can be output through the winding design. In practical applications, those skilled in the art can adjust the output voltage to meet the actual requirement according to the actual situation.

The feedback circuit 140 is connected between the second secondary winding and the power input circuit 110, and is configured to feed back the condition of the output voltage of the second secondary winding to the power input circuit 110, so that the power input circuit 110 can know the condition of the secondary output, so as to facilitate adjustment. In one embodiment, the feedback circuit 140 may specifically include a first diode and a first transistor. The anode of the first diode is connected with at least one circuit, the cathode of the first diode is grounded, the emitter of the first triode is grounded, and the collector of the first triode is connected with the power input circuit 110. The light emitted from the first diode is attenuated, so that the collector current of the first transistor is attenuated, and a feedback signal can be generated and input to the power input circuit 110. Those skilled in the art can also understand the specific functions of the feedback circuit 140 and, according to the actual situation, replace the feedback isolation circuit with other electronic components with the same functions.

The constant current control circuit 130 includes a first control terminal, a second control terminal, a third control terminal and a constant current output terminal; one end of the first secondary winding is connected with the first control end, and the other end of the first secondary winding is connected with the third control end, so that the constant current control circuit 130 and the first secondary winding form a voltage control loop; one end of the second secondary winding is connected to the second control terminal, and the other end is connected to the third control terminal, so that the constant current control circuit 130 and the second secondary winding form a current control loop. The output current of the constant current output end is constant, and the constant current output end is connected with the display screen interface circuit to supply power to the display screen.

Therefore, a voltage control loop is formed by the first secondary winding and the constant current control circuit to control the value of the output voltage of the constant current control circuit; the current control loop is formed by the second secondary winding and the constant current control circuit, and the output current of the constant current control circuit is limited, so that the constant current output of the display screen interface is realized, the stability of the output current is ensured, the conversion of the commercial power to the constant current power supply of the display screen is realized, the brightness stability of the display screen is improved, and the display screen has good market application value.

Fig. 2 is a circuit diagram illustrating a secondary side of a transformer according to an exemplary embodiment. As shown in fig. 2, the secondary side of the transformer has a first secondary winding and a second secondary winding. In one embodiment, the secondary side may have a first end 4, a second end 2, and a common end 1. The common terminal 1 is located on the same side of the first terminal 4 and the second terminal 2 and may share a winding. The winding between the first end 4 and the common end 1 forms a first secondary winding; the windings between the second end 2 and the common end 1 form a second secondary winding, the number of windings of the first secondary winding being greater than the number of windings of the second secondary winding. It is easily understood that the induced current and induced voltage on the first and second secondary windings of the transformer can be adjusted by adjusting the pulse width and pulse frequency of the input voltage of the primary winding.

In this embodiment, the constant current control circuit may include a constant current control chip. The constant current control chip at least comprises a first control end Vctrl, a second control end Ictrl, a third control end Vsense and a constant current output end Vout. As shown in fig. 2, specifically, the first secondary winding forms a voltage control loop through the first control terminal Vctrl, the second control terminal Ictrl, and the constant current output terminal Vout, and is used for controlling the output voltage of the constant current output section. The second secondary winding forms a current control loop through the third control terminal Vsense, the second control terminal Ictrl and the constant current output terminal Vout and is used for limiting the output current of the constant current output terminal, so that the output current of the constant current output terminal is kept stable through controlling the voltage and the current of the constant current output terminal. More specifically, the first terminal 4 of the first secondary winding is input to the first control terminal Vctrl through the diode D107 and the resistor R121. The second terminal 2 of the first secondary winding is indirectly input to the third control terminal Vsense through the diode D108, the resistor R111, the resistor R112, the capacitor C107 and the resistor R114, and the common terminal 1 is input to the second control terminal Ictrl. The first control terminal Vctrl is connected between the resistor R121 and the resistor R121, and the other end of the resistor R116 is grounded, so that the voltage of the first control terminal Vctrl can be determined by determining the resistance value of the resistor R121. And, one end of a common end formed by connecting the resistor R118 and the resistor R119 in parallel is connected to the third control end Vsense, and the other end is grounded, so that the current of the circuit control loop can be determined by determining the resistance value of the resistor R119 of the resistor R118. In addition, the third control terminal Vsense is grounded through a resistor R115, and the current and voltage input to the third control terminal Vsense are cooperatively controlled.

The constant current output terminal Vout is used for supplying power to the display screen, and specifically, the constant current output terminal Vout is electrically connected with the display screen interface circuit. The constant current output end Vout is connected to the positive input end of the display screen interface CN2 through the capacitor C106, the resistor R113, the resistor R121 and the inductor L102, and the negative input end of the display screen interface CN2 is grounded, so that the constant current output end Vout supplies power to the display screen.

The feedback circuit is connected between the second secondary winding and the power input circuit and used for generating a feedback signal to the power input circuit. Specifically, as shown in fig. 2, the feedback circuit includes a first diode LED103 and a first diode Q102. The second end 2 of the second secondary winding is input to the anode of the first diode LED103 through a diode D108 and a resistor R111, and the anode of the first diode is indirectly connected to the constant current output end of the constant current control chip IC 2; the cathode of the first diode LED103 is indirectly grounded through a capacitor C106, a resistor R113 and a resistor R116, the emitter of the first triode Q102 is grounded, and the output terminal COMP of the collector of the first triode Q102 is electrically connected to the power input circuit to feed back a feedback signal to the power input circuit. When the output voltage of the constant current output end changes, the light emitted by the first diode changes, so that the collector current of the first triode changes, a feedback signal is generated and input to the power input circuit, and the power input circuit can control the pulse frequency and the pulse width of the voltage input to the primary side of the transformer.

In one embodiment, the display interface circuit further includes a capacitor E103, a capacitor C109, a capacitor E104, and a capacitor L102 for filtering to eliminate electrical interference.

In one embodiment, the display interface circuit also includes an LED102 and a resistor R128 to light up when the display interface circuit has power to give a power on indication.

In one embodiment, a capacitor E105 and a capacitor C105 connected in parallel may be disposed between two taps of the second secondary winding, and may absorb surge voltage and prevent high frequency interference, thereby serving as a stabilizing and protecting circuit.

Fig. 3 is a schematic diagram illustrating an internal structure of a constant current control chip IC2 according to a specific example embodiment. As shown in fig. 3, the constant current control chip IC2 has 6 pins. Wherein, the first control terminal Vctrl is an input pin of the voltage control loop_。Pin GND is grounded. The constant current output terminal Vout is used to output a constant current. The second control terminal Ictrl and the third control terminal Vsense are input terminals of the circuit control loop. The VCC end is a power supply input end. In this embodiment, the constant current control chip IC2 is a chip AP4313, and the AP4313 includes a reference voltage Vref of 1.21V with an accuracy of ± 1%, a current detection current, and two operational amplifiers. Therefore, voltage control can be realized through the built-in high-precision reference voltage of the AP4313, compensation is realized through the formed current loop, and constant current output is realized.

The output voltage Vout of the constant current output terminal is:

Vout ＝Vref*(R121+R116)/R116 (1)

the current Iout output by the constant current output end is as follows:

Iout＝Vsense/Rss，(2)

wherein, 1/Rss is 1/R118+1/R119, and Vref is the reference voltage.

Fig. 4 is a circuit diagram illustrating a primary side of a transformer according to an example embodiment. The primary side of the transformer has a power input circuit. And the input end of the primary winding of the transformer is electrically connected with the output end of the power input circuit. As shown in fig. 4, the power input circuit may include a voltage control chip IC1, a switching device Q101, a power interface CN01, a filter circuit, and a rectifier circuit.

Wherein, power interface CN01 supplies the commercial power to insert. The input end of the filter circuit is electrically connected with the output end of the power interface. Specifically, as shown in fig. 4, the power interface CN01 is electrically connected to the filter circuit through a thermistor NTC and a FUSE 1. The thermistor NTC is used for preventing power-on impact, and the FUSE1 is used for ensuring the safe operation of the circuit. The filter circuit comprises a capacitor C101 and a common membrane inductor L101. The filter circuit is used for preventing the influence of the fluctuation of the mains supply power grid on the constant-current power supply circuit of the display screen on one hand, and preventing the influence of the constant-current power supply circuit of the display screen on the mains supply power grid on the other hand. One section of the voltage dependent resistor Z101 is connected with the anode of the power input circuit, and the other end is connected with the cathode for preventing surge impact.

The output end of the filter circuit is electrically connected with the input end of the rectifying circuit. The rectifying circuit specifically includes diodes D101, D102, D103 to D104 and a capacitor E101, so as to rectify and convert the commercial power into smoother direct current. Further, the power input circuit may further include a power access indication circuit, and the power access indication circuit may specifically include a resistor R127 and a light emitting diode LED101, so as to indicate a power access state by turning on or off the diode.

The rectifying circuit is connected with the primary winding of the transformer and the constant current control chip so as to output an electric signal required by the primary winding of the transformer under the control of the voltage control chip. Specifically, as shown in FIG. 4, the constant current control chip IC1 has 6 pins. The 1 st pin GND is used for grounding. The 2 nd pin COMP is used for receiving a feedback signal. The 3 rd pin RT is used for externally connecting the switching frequency setting resistor R117. The 4 th pin driving signal output OUT is for outputting a driving signal. The 5 th pin VCC is used for connecting a power supply circuit of the chip. The 6 th pin CS is used to detect the current of the switching device. Accordingly, the switching device Q101 has a first pin, a second pin, and a control pin. The first pin is connected to one end of the primary winding, the second pin is connected to one end of a resistor R123, and the other end of the resistor R123 is grounded. The input terminal of the control pin is connected to the driving signal output terminal OUT, so that the constant current control chip IC1 can control the switching device Q101 to be turned on or off, and in combination with the diode D105, the resistor R104, and the capacitor C102, control the width and frequency of the electrical signal pulse output to the primary winding of the transformer T101. In addition, a circuit formed by the resistor R102, the resistor R101, the resistor R105, the capacitor E102 and the diode D106 is mainly supplied with power by a constant current control chip IC1, and the model of the constant current control chip IC1 can be LD 7535. Thereby, a safe and reliable power supply to the primary winding of the transformer can be achieved. The capacitor C108 is a safety capacitor for filtering out common-film interference in primary and secondary coupling.

In summary, when all the loads on the display screen change, the output voltage will change accordingly, and since the output current of the constant current circuit of the display screen can be stabilized, the current is maintained constant, so that the brightness of the display screen can be stabilized, and energy saving can be realized.

According to an aspect of the application, still provide a display screen, the display screen includes first display subregion and second display subregion, and the LED lamp pearl quantity of first display subregion and second display subregion can be the same also can be different. The display screen is electrically connected with the display screen constant current power supply circuit to obtain the electric power provided by the display screen constant current power supply circuit. The output stream of the display screen interface is constant when the first display partition and/or the second display partition is lit. Wherein, display screen constant current power supply circuit includes at least:

the power input circuit is connected to the mains supply;

According to an aspect of the application, a washing machine is also provided, and the washing machine at least comprises a display screen and a display screen constant current supply circuit for supplying power to the display screen. The display screen comprises a first display partition and a second display partition. The display screen constant current power supply circuit is used for supplying power to the display screen and keeping the output current of the display screen constant current power supply circuit constant under the condition that the first display subarea and/or the second display subarea are/is lightened. Wherein, display screen constant current power supply circuit includes at least:

the power input circuit is connected to the mains supply;

The inventive concepts of the display screen and the washing machine are consistent with the inventive concept of the display screen constant current power supply circuit, and the detailed description is omitted here.

While the present application has been described with reference to several exemplary embodiments, it is understood that the terminology used is intended to be in the nature of words of description and illustration, rather than of limitation. As the present application may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.

Claims

1. A constant current supply circuit for a display screen is characterized by comprising:

the power input circuit is connected to the mains supply;

the input end of the primary winding of the transformer is electrically connected with the output end of the power input circuit; the transformer also has a first secondary winding and a second secondary winding;

the feedback circuit is connected between the second secondary winding and the power input circuit and used for generating a feedback signal to the power input circuit;

2. The circuit of claim 1, wherein the secondary winding of the transformer has a first end, a second end, and a common end; the winding between the first end and the common end forms a first secondary winding; the winding between the second end and the common end forms a second secondary winding; the common end is located on the same side of the first end as the second end.

3. The circuit of claim 2, wherein the common terminal is electrically connected to the third control terminal; the first end is electrically connected with the first control end; the second end is electrically connected with the second control end;

an output end of the first control end and an output end of the reference voltage are respectively electrically connected with two input ends of the first operational amplifier so as to input the output voltage of the first end and the reference voltage to the first operational amplifier; the second control end and the third control end are respectively and electrically connected with two input ends of the second operational amplifier so as to input output signals of the second end and the common end to the second operational amplifier; the first operational amplifier and the second operational amplifier have a common output end, and the common output end is the constant current output end.

4. The circuit of claim 1, wherein the feedback circuit comprises a first diode and a first transistor; the constant current output end is electrically connected with the anode of the first diode, and the cathode of the first diode is grounded; the emitting electrode of the first triode is grounded, and the collecting electrode of the first triode is electrically connected with the power input circuit; when the output signal of the constant current output end changes, the light emitted by the first diode changes, so that the collector current of the first triode changes, and a feedback signal is generated and input to the power input circuit.

5. The circuit of claim 1, wherein the power input circuit comprises a voltage control chip; the voltage control chip is provided with a feedback signal input end and a driving signal output end; the feedback signal input end is electrically connected with the output end of the feedback circuit; the driving signal output end is electrically connected with a primary coil of the transformer so as to adjust a driving signal output to the primary coil according to a feedback signal.

6. The circuit of claim 5, wherein the power input circuit further comprises a switching device; the switching device has a first pin, a second pin and a control pin; the first pin is connected to the primary winding; the second pin is grounded, the input end of the control pin is electrically connected with the driving signal output end to receive a driving signal, and the driving signal is used for controlling to obtain the connection or disconnection of the first pin and the second pin.

7. The circuit of claim 5, wherein the power input circuit further comprises a power interface, a filter circuit, and a rectifier circuit; the power interface is used for connecting commercial power; the input end of the filter circuit is electrically connected with the output end of the power interface, and the output end of the filter circuit is electrically connected with the input end of the rectifying circuit; the output end of the rectifying circuit is electrically connected with the primary winding of the transformer and the voltage control chip so as to output an electric signal required by the primary winding of the transformer under the control of the voltage control chip.

8. The circuit of claim 1, wherein the constant current control circuit comprises a constant current control chip.

9. A display screen is characterized by comprising a first display subarea and a second display subarea; the display screen is powered by using the display screen constant current supply circuit according to any one of claims 1 to 8, and the output current of the display screen constant current supply circuit is constant under the condition that the first display subarea and/or the second display subarea are/is lightened.

10. A washing machine, characterized in that the washing machine comprises:

the display screen comprises a first display partition and a second display partition;

the display screen constant current supply circuit according to any one of claims 1 to 8, wherein the display screen constant current supply circuit is configured to supply power to the display screen, and an output current of the display screen constant current supply circuit is constant when the first display section and/or the second display section are/is lit.