CN215933168U

CN215933168U - Drive circuit and display device

Info

Publication number: CN215933168U
Application number: CN202122052538.5U
Authority: CN
Inventors: 金志伟
Original assignee: Shenzhen TCL New Technology Co Ltd
Current assignee: Shenzhen TCL New Technology Co Ltd
Priority date: 2021-08-27
Filing date: 2021-08-27
Publication date: 2022-03-01
Anticipated expiration: 2031-08-27

Abstract

The application provides a driving circuit and a display device, wherein a constant current module of the driving circuit is electrically connected with a backlight source and can control the current of the backlight source; the first winding of the transformer can output a first voltage and can be electrically connected with the voltage supply module; the voltage supply module can be electrically connected with the backlight source and provides voltage for the backlight source; the transformation module is respectively electrically connected with the second winding and the backlight source. Therefore, the voltage transformation module can change the voltage of the backlight lamp source to enable the first voltage of the first winding and the second voltage of the second winding to be in a constant voltage range, and the working frequency of the transformer can also be in a constant frequency range, so that the display device does not frequently change the control instruction of the transformer, and the display device controls the transformer more stably.

Description

Drive circuit and display device

Technical Field

The present application relates to a backlight driving technology, and in particular, to a driving circuit and a display device.

Background

The backlight constant current driving circuit is commonly used for driving a Light Emitting Diode (LED) lamp, and adjusts a current of the LED lamp by using a constant current module, so as to change a brightness of the LED lamp to adjust a brightness change of the display device.

In the related art, the current control of the LED lamp may be implemented by the transformer and the backlight constant current driving circuit, but when the current of the LED lamp changes in a large amplitude and frequently, the output voltage of the transformer also changes frequently, and the operating frequency of the transformer changes frequently with the change of the output voltage of the transformer, so that the display device is not easy to control the transformer stably.

SUMMERY OF THE UTILITY MODEL

The application provides a drive circuit and display device, the current variation of LED lamp can not produce great influence to the voltage of transformer, and display device is more stable to the control of transformer.

In a first aspect, the present application provides a driving circuit comprising:

the constant current module is electrically connected with the backlight source and is used for controlling the current of the backlight source;

the transformer comprises a first winding and a second winding, wherein the first winding is used for outputting a first voltage, and the second winding is used for outputting a second voltage;

the voltage supply module is respectively electrically connected with the first winding and the backlight source and is used for supplying voltage to the backlight source; and

and the voltage transformation module is respectively electrically connected with the second winding and the backlight source and is used for controlling the voltage of the backlight source according to the current of the backlight source so as to enable the first voltage and the second voltage to be in a constant voltage range.

In some embodiments, the voltage transformation module is a buck conversion circuit.

In some embodiments, the second winding includes a first port and a second port, the second port being grounded; the voltage transformation module comprises:

a voltage control element having one end electrically connected to the first port;

one end of the first inductor is electrically connected with the other end of the voltage control element;

one end of the first capacitor is electrically connected with the other end of the first inductor and the backlight source respectively, and the other end of the first capacitor is grounded;

one end of the second capacitor is electrically connected with the first port, and the other end of the second capacitor is grounded; and

and one end of the first diode is electrically connected between the voltage control element and the first inductor, and the other end of the first diode is grounded.

In some embodiments, the driving circuit further comprises:

and one end of the second diode is electrically connected with the first port, the other end of the second diode is electrically connected with the voltage control element and the second capacitor respectively, and the second diode is used for rectifying the voltage output by the first port.

In some embodiments, the backlight source comprises:

one end of the first light source is electrically connected with the voltage supply module, and the other end of the first light source is electrically connected with the constant current module; and

one end of the second light source is electrically connected with the voltage supply module, and the other end of the second light source is electrically connected with the voltage transformation module; wherein the content of the first and second substances,

the constant current module, the first lamp source, the voltage supply module, the first winding, the second lamp source and the voltage transformation module form a first current loop.

In some embodiments, the backlight source further comprises:

one end of the third light source is electrically connected with the voltage supply module, and the other end of the third light source is electrically connected with the constant current module; and

one end of the fourth light source is electrically connected with the voltage supply module, and the other end of the fourth light source is electrically connected with the voltage transformation module; wherein the content of the first and second substances,

the constant current module, the third light source, the voltage supply module, the first winding, the fourth light source and the voltage transformation module form a second current loop;

the transformer is used for conducting the first current loop at a first level, and the transformer is used for conducting the second current loop at a second level, wherein the second level is different from the first level.

In some embodiments, the first winding includes a third port and a fourth port; the pressure supply module includes:

one end of the third capacitor is electrically connected with the third port;

one end of the third diode is electrically connected with the other end of the third capacitor, and the other end of the third diode is electrically connected with the first light source;

one end of the fourth diode is electrically connected with the fourth port, and the other end of the fourth diode is electrically connected with the second light source;

one end of the fifth diode is electrically connected with the fourth port, and the other end of the fifth diode is electrically connected with the third light source;

one end of the sixth diode is electrically connected between the third capacitor and the third diode, and the other end of the sixth diode is electrically connected with the fourth light source.

In some embodiments, the driving circuit further comprises:

a converter electrically connected to the transformer, the converter for providing the first voltage and the second voltage to the transformer; and

a feedback electrically connected to the inverter and the second winding, respectively, the feedback for feeding back the first voltage and the second voltage to the inverter.

In some embodiments, the constant current module comprises:

a current control element electrically connected to the backlight source; and

the constant current chip is respectively and electrically connected with the current control element and the voltage transformation module, and is used for controlling the current output by the current control element and controlling the voltage output by the voltage transformation module.

In a second aspect, embodiments of the present application further provide a display device, including the driving circuit as described above.

The driving circuit comprises a constant current module, a transformer, a voltage supply module and a voltage transformation module, wherein the constant current module is electrically connected with a backlight source and can control the current of the backlight source; the first winding of the transformer can output a first voltage and can be electrically connected with the voltage supply module; the voltage supply module can be electrically connected with the backlight source and provides voltage for the backlight source; the transformation module is respectively electrically connected with the second winding and the backlight source. Based on this, the technical problem of unstable control of the transformer caused by frequent change of the working frequency of the transformer in the related art can be solved by the scheme of the application, the voltage transformation module of the driving circuit of the application can change the voltage of the backlight source according to the change of the current of the backlight source, so that the first voltage of the first winding and the second voltage of the second winding are in a constant voltage range, and the working frequency of the transformer can also be in a constant frequency range, so that the control instruction of the transformer cannot be frequently changed by the display device, and the control of the transformer by the display device is more stable.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the application, and that other drawings can be derived from these drawings by a person skilled in the art without inventive effort.

For a more complete understanding of the present application and its advantages, reference is now made to the following descriptions taken in conjunction with the accompanying drawings. Wherein like reference numerals refer to like parts in the following description.

Fig. 1 is a first connection diagram of a driving circuit according to an embodiment of the present disclosure.

Fig. 2 is a second connection schematic diagram of a driving circuit according to an embodiment of the present disclosure.

Fig. 3 is a third connection diagram of a driving circuit according to an embodiment of the present disclosure.

Fig. 4 is a third connection diagram of a driving circuit according to an embodiment of the present disclosure.

Fig. 5 is a fourth connection diagram of a driving circuit according to an embodiment of the present disclosure.

Fig. 6 is a first current diagram of the driving circuit shown in fig. 5.

Fig. 7 is a second current diagram of the driving circuit shown in fig. 5.

Fig. 8 is a schematic diagram of control signals of the driving circuit shown in fig. 5.

Fig. 9 is a schematic structural diagram of a display device according to an embodiment of the present disclosure.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to fig. 1 to 9 in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The embodiment of the application provides a driving circuit 100, and the driving circuit 100 may be disposed in a display device 10 and an intelligent television to realize bright screen display of the display device 10 and the intelligent television. Referring to fig. 1, fig. 1 is a first connection diagram of a driving circuit 100 according to an embodiment of the present disclosure. The driving circuit 100 may include a constant current module 110, a transformer 120, a voltage supply module 130, and a voltage transformation module 140.

The constant current module 110 is electrically connected to the backlight source 200, and the constant current module 110 may provide current to the backlight source 200 and may control the magnitude of the current passing through the backlight source 200, so that the backlight source 200 may be turned on, turned off, or have different brightness under the control of the constant current module 110. It can be understood that the backlight source 200 may be an LED strip, an LED light bar, or the like, and the structure of the backlight source 200 is not limited in this embodiment.

The transformer 120 may include a first winding 121 and a second winding 122, the first winding 121 and the second winding 122 may be secondary windings of the transformer 120, the transformer 120 may further include a third winding 123, the third winding 123 may be a primary winding, and the transformer 120 may implement the voltage variation through the third winding 123, the first winding 121, and the second winding 122. Wherein the first winding 121 may output a first voltage, which may be a voltage difference between two ports (e.g., the third port a3 and the fourth port a4) of the first winding 121; the second winding 122 may output a second voltage, which may be a difference in voltages across ports (e.g., the first port a1 and the second port a2) of the second winding 122. It will be appreciated that the ratio of the first voltage to the second voltage may be related to the turn ratio of the first winding 121 to the second winding 122, for example, the first voltage may be equal to N times the second voltage, and the value of N may be the turn ratio of the first winding 121 to the second winding 122. When the first voltage is changed, the second voltage can be proportionally changed.

The voltage supplying module 130 may be electrically connected to the first winding 121, the voltage supplying module 130 may also be electrically connected to the backlight source 200, and the voltage supplying module 130 may receive the voltage transmitted by the first winding 121 and may provide the voltage to the backlight source 200 to maintain the lighting state of the backlight source 200. It can be understood that, since the voltage supplying module 130 includes a plurality of electronic components, such as capacitors and diodes, the voltage value supplied by the voltage supplying module 130 to the backlight source 200 is not necessarily the first voltage, and the voltage value supplied by the voltage supplying module 130 to the backlight source 200 is adapted according to the current passing through the backlight source 200, which is not limited in the embodiment of the present application.

The transforming module 140 may be electrically connected to the second winding 122, the transforming module 140 may also be electrically connected to the backlight source 200, the transforming module 140 may control the voltage of the backlight source 200 according to a change of a current passing through the backlight source 200, since the voltage of the backlight source 200 may affect the first voltage of the first winding 121, the transforming module 140 may control the first voltage of the first winding 121, and since the voltages of the first winding 121 and the second winding 122 are simultaneously changed, the transforming module 140 may change the voltage of the backlight source 200 so that the first voltage of the first winding 121 and the second voltage of the second winding 122 are in a constant voltage range.

When the constant current module 110 changes the current passing through the backlight source 200, the brightness of the backlight source 200 changes, the voltage applied to the backlight source 200 by the voltage supply module 130 also changes, and at this time, the first voltage of the first winding 121 electrically connected to the voltage supply module 130 also changes. Since the operating frequency of the transformer 120 is related to the voltage of the transformer 120, when the voltage of the transformer 120 changes by a large amount, the operating frequency of the transformer 120 also changes. When the constant current module 110 greatly changes the current of the backlight source 200 for many times, the operating frequency of the transformer 120 is also frequently changed, which is not favorable for the display device 10 to control the transformer 120.

In the driving circuit 100 of the embodiment of the application, the transforming module 140 is electrically connected to the second winding 122 and the backlight source 200, respectively, the transforming module 140 may change the voltage of the backlight source 200 to make the first voltage of the first winding 121 and the second voltage of the second winding 122 in a constant voltage range, at this time, the operating frequency of the transformer 120 may also be in a constant frequency range, and the display device 10 may not change the frequency of the control instruction for the transformer 120, so that the control of the transformer 120 by the display device 10 is more stable.

The voltage transformation module 140 may be a BUCK conversion circuit (BUCK circuit). Referring to fig. 2, fig. 2 is a second connection schematic diagram of the driving circuit 100 according to the embodiment of the disclosure. The transforming module 140 may include a voltage control element Q1, a first inductor L1, a first capacitor C1, a second capacitor C2, and a first diode D1, and the transforming module 140 may form a BUCK-down DC-DC circuit.

The second winding 122 may include a first port a1 and a second port a2, and one end of the voltage control element Q1 may be electrically connected to the first port a 1; one end of the first inductor L1 may be electrically connected to the other end of the voltage control element Q1; one end of the first capacitor C1 may be electrically connected to the other end of the first inductor L1 and the backlight source 200, respectively, and the other end of the first capacitor C1 may be grounded; one end of the second capacitor C2 may be electrically connected with the first port a1, and the other end of the second capacitor C2 may be grounded; one end of the first diode D1 may be electrically connected between the voltage control element Q1 and the first inductor L1, and the other end of the first diode D1 may be grounded.

It is understood that the voltage control element Q1 may be a transistor, a field effect transistor, or the like. The voltage control element Q1 may change the output voltage by adjusting the duty ratio, and the voltage control element Q1 may change the voltage at the terminal point where the first capacitor C1 is connected between the first inductor L1 and the backlight source 200, so that the voltage control element Q1 may change the voltage of the backlight source 200.

It is understood that the second capacitor C2 may store energy for filtering, and the second capacitor C2 may filter out noise in the voltage signal transmitted by the second winding 122. The first diode D1 may function as a free-wheeling current, and the first diode D1 may make the output current of the transforming module 140 a continuous current.

In some embodiments, referring to fig. 2 again, the driving circuit 100 may further include a second diode D2. One end of the second diode D2 may be electrically connected to the first port a1 of the second winding 122, the other end of the second diode D2 may be electrically connected to the voltage control element Q1 and the second capacitor C2, respectively, and the voltage across the second capacitor C2 may be approximately equal to the second voltage of the second winding 122. The second diode D2 may be a rectifying diode, and the second diode D2 may rectify the voltage output from the first port a1, so that the ac voltage output from the first port a1 is converted into a dc voltage.

The transformation module 140 in the embodiment of the application is a BUCK DC-DC reduction circuit, the transformation module 140 can transform a specific DC voltage (rectified voltage output by the second winding 122) into a variable DC voltage (voltage of the backlight source 200), and the transformation module 140 has a simple structure, low internal loss, small temperature drift, and high output voltage stability.

It should be noted that the above is merely an exemplary example of the transformation module 140 according to the embodiment of the present application, for example, the transformation module 140 may add a combination of one or more components such as a capacitor, an inductor, and a resistor to the structure shown in fig. 2; for another example, the voltage transforming module 140 may also be a BOOST converter circuit (BOOST circuit); the embodiment of the present application does not limit the specific structure of the voltage transformation module 140.

In some embodiments, referring to fig. 3, fig. 3 is a third connection schematic diagram of the driving circuit 100 according to the embodiment of the disclosure, and the backlight source 200 may include a first light source LED1 and a second light source LED 2.

One end of the first light source LED1 may be electrically connected to the voltage supply module 130, and the other end of the first light source LED1 is electrically connected to the constant current module 110; one end of the second light source LED2 is electrically connected to the voltage supply module 130, and the other end of the second light source LED2 is electrically connected to the voltage transformation module 140. The constant current module 110, the first lamp LED1, the voltage supply module 130, the first winding 121, the second lamp LED2, and the voltage transformation module 140 may form a first current loop.

The first current loop of the embodiment of the application can control the brightness of the first light source LED1 and the second light source LED2 by executing the control command once, and the first current loop can control more LED lamps, so that the structure of the driving circuit 100 can be simplified; on the other hand, the control efficiency of the LED lamp can be improved.

In some embodiments, referring to fig. 4, fig. 4 is a fourth connection schematic diagram of the driving circuit 100 according to the embodiment of the disclosure, and the backlight source 200 may further include a third light source LED3 and a fourth light source LED 4.

One end of the third light source LED3 may be electrically connected to the voltage supply module 130, and the other end of the third light source LED3 may be electrically connected to the constant current module 110; one end of the second four LED lamp may be electrically connected to the voltage supply module 130, and the other end of the fourth light source LED4 may be electrically connected to the voltage transformation module 140. The constant current module 110, the third light source LED3, the voltage supply module 130, the first winding 121, the fourth light source LED4, and the voltage transformation module 140 may form a second current loop.

It is understood that the transformer 120 may conduct the first current loop at a first level and the transformer 120 may conduct the second current loop at a second level, and the first level may be different from the second level. For example, the first level may be a high level and the second level may be a low level. Accordingly, the transformer 120 can conduct the first current path and the second current path under the control of high and low levels, respectively.

In the driving circuit 100 of the embodiment of the application, the transformer 120 can control the first light source LED1, the second light source LED2, the third light source LED3, and the fourth light source LED4 under different level control, the driving circuit 100 can enable the single-channel constant current module 110 (backlight IC module) to realize four backlight outputs, the requirement of the driving circuit 100 on the constant current module 110 is not high, and meanwhile, the driving circuit 100 can also improve the control efficiency of the LED lamp.

Referring to fig. 5 to 7, fig. 5 is a fourth connection diagram of the driving circuit 100 according to the embodiment of the present disclosure, fig. 6 is a first current diagram of the driving circuit 100 shown in fig. 5, and fig. 7 is a second current diagram of the driving circuit 100 shown in fig. 5. The first winding 121 of the transformer 120 may include a third port a3 and a fourth port a4, and the voltage supply module 130 may include components such as a third capacitor C3, a third diode D3, a fourth diode D4, a fifth diode D5, and a sixth diode D6.

One end of the third capacitor C3 may be electrically connected with the third port a3 of the first winding 121; one end of the third diode D3 may be electrically connected to the other end of the third capacitor C3, and the other end of the third diode D3 may be electrically connected to the first light source LED 1; one end of the fourth diode D4 may be electrically connected with the fourth port a4, and the other end of the fourth diode D4 may be electrically connected with the second light source LED 2; one end of the fifth diode D5 may be electrically connected with the fourth port a4, and the other end of the fifth diode D5 may be electrically connected with the third light source LED 3; one end of the sixth diode D6 may be electrically connected between the third capacitor C3 and the third diode D3, and the other end of the sixth diode D6 may be electrically connected to the fourth light source LED 4.

As shown in fig. 6, when the third port a3 of the first winding 121 is at a high level, the third diode D3 is turned on, the fourth diode D4 is turned on, the fifth diode D5 is turned off, and the sixth diode D6 is turned off, so that a current may flow from the third port a3 through the third capacitor C3, the third diode D3, the first lamp LED1, the constant current module 110 (e.g., the current control element Q2 and the current detection resistor R1 of the constant current module 110), the first capacitor C1, the second lamp LED2, the fourth diode D4, the fourth port a4, and the third port a3, thereby forming a first current loop.

As shown in fig. 7, when the fourth port a4 of the first winding 121 is at a high level, the third diode D3 is turned off, the fourth diode D4 is turned off, the fifth diode D5 is turned on, and the sixth diode D6 is turned on, so that a current may flow from the fourth port a4 through the fifth diode D5, the third lamp source LED3, the constant current module 110 (e.g., the current control element Q2 and the current detection resistor R1 of the constant current module 110), the first capacitor C1, the fourth lamp source LED4, the sixth diode D6, the third capacitor C3, the third port a3, and the fourth port a4, thereby forming a second current loop.

It is understood that, in the above embodiment, the third capacitor C3 may achieve the effect of blocking the flow of direct current; the third diode D3, the fourth diode D4, and the fifth diode D5 may perform a function of rectifying a free-wheeling current, and may convert an ac voltage into a dc voltage.

Referring to fig. 5 to 7 again, the voltage supplying module 130 may further include a fourth capacitor C4 and a fifth capacitor C5. One end of the fourth capacitor C4 may be electrically connected between the fifth diode D5 and the third light source LED3, and the other end of the fourth capacitor C4 may be electrically connected between the sixth diode D6 and the fourth light source LED 4. One end of the fifth capacitor C5 may be electrically connected between the third diode D3 and the first light source LED1, and the other end of the fifth capacitor C5 may be electrically connected between the fourth diode D4 and the second light source LED 2.

It is understood that the fourth capacitor C4 and the fifth capacitor C5 may function as energy storage filters. The fourth capacitor C4 and the fifth capacitor C5 can filter noise in the voltage signal rectified by the third diode D3 and the fifth diode D5, so that the voltage signal in the driving circuit 100 is more flat and the signal quality of the driving circuit 100 is better.

The voltage supply module 130 of the embodiment of the application can convert the ac signal transmitted by the transformer 120 into the dc signal, and can filter the noise in the driving circuit 100, the driving circuit 100 can transmit a signal with better quality, and the driving circuit 100 has better control quality for the LED lamp. Meanwhile, the voltage supply module 130 can realize the conduction of the first current loop and the second current loop under different levels of the transformer 120 through the electronic components, and the control efficiency of the voltage supply module 130 on the plurality of LED lamps is higher.

It should be noted that, the above is only an exemplary example of the voltage supplying module 130 in the embodiment of the present application, for example, the voltage supplying module 130 may further include any combination of one or more components such as a resistor, a capacitor, and an inductor, and the structure of the voltage supplying module 130 that can supply voltage to a plurality of LED lamps is within the protection scope of the embodiment of the present application, and the embodiment of the present application is not limited to the specific structure of the voltage supplying module 130.

In some embodiments, referring to fig. 5 again, the constant current module 110 may include a constant current chip 111, a current control element Q2, and a current detection resistor R1.

The constant current chip 111 may include at least two pins, for example, a P-DIM pin and an ISET pin, where the P-DIM pin may output a pulse timing adjustment signal and the ISET pin may output a current signal.

One end of the current control element Q2 may be electrically connected to the constant current chip 111, for example, to the P-DIM pin, the other end of the current control element Q2 may be electrically connected to the backlight source 200, for example, to the first light source LED1 and the third light source LED3, and the current control element Q2 may adjust the duty ratio according to the pulse timing adjustment signal output by the P-DIM pin to change the average value of the output power level.

It is understood that the current control element Q2 may be a transistor, a field effect transistor, or the like. The current control element Q2 can change the output current by adjusting the duty cycle, so that the current control element Q2 can change the dimming of the LED lamp.

One end of the current detection resistor R1 may be electrically connected to the constant current chip 111, for example, to an ISET pin of the constant current chip 111, one end of the current detection resistor R1 may also be electrically connected to the current control element Q2 to transmit a current signal to the current control element Q2, and the other end of the current detection resistor R1 may be grounded; the current detection resistor R1 can detect the current signal of the ISET pin to prevent the current from being too large and affecting the normal operation of the driving circuit 100.

The constant current module 110 of the embodiment of the application can control the magnitude of the current transmitted to the first light source LED1 and the third light source LED3 through the current control element Q2, and the constant current module 110 can control the brightness of the LED lamp.

The constant current chip 111 may be electrically connected to the transformer module 140, and the constant current chip 111 may control the transformer module 140 to change the voltage of the transformer module 140, so as to control the transformer module 140 to compensate for the voltage variation of the backlight source 200, so that the first voltage and the second voltage of the transformer 120 may not vary with the current of the backlight source 200.

As shown in fig. 5, the constant current chip 111 may further include a third pin, which may be electrically connected to the transformer module 140, for example, electrically connected to the voltage control element Q1 of the transformer module 140, so that the constant current chip 111 may be electrically connected to the current control element Q2, the constant current chip 111 may be electrically connected to the voltage control element Q1, and the constant current chip 111 may control the magnitude of the current output by the current control element Q2 or the magnitude of the voltage output by the first capacitor C1 of the transformer module 140.

For example, at time T1, the constant current chip 111 controls the current control element Q2 to transmit a current signal of I1 to the backlight source 200, and the constant current chip 111 controls the voltage control element Q1 to transmit a voltage signal of V1 to the first capacitor C1, where a voltage difference between the third port a3 and the fourth port a4 of the first winding 121 of the transformer 120 — the first voltage is Vout 1; at time T2, the constant current chip 111 needs to control the current control element Q2 to transmit a current signal of I2 to the backlight source 200, and the constant current chip 111 controls the voltage control element Q1 to transmit a voltage signal of V2 to the first capacitor C1, at this time, the voltage difference between the third port a3 and the fourth port a4 of the first winding 121 of the transformer 120 — the first voltage is still Vout 1; so that the driving circuit 100 can ensure that the first voltage of the transformer 120 is within a constant voltage range.

It is understood that the magnitude of V2 transmitted by the voltage control element Q1 to the first capacitor C1 can be adapted to the magnitude of I2 transmitted by the current control element Q2 to the backlight source 200. For example, referring to fig. 8, fig. 8 is a schematic diagram of control signals of the driving circuit 100 shown in fig. 5.

As shown in fig. 8, the voltage of the first light source LED1 is VLED1, the voltage of the second light source LED2 is VLED2, the voltage of the third light source LED3 is VLED3, and the voltage of the fourth light source LED4 is VLED 4; the voltage difference between the third port a3 and the fourth port a4 of the first winding 121-the first voltage is Vout1, the voltage difference between the first port a1 and the second port a2 of the second winding 122-the second voltage is Vout2, the voltage of the first capacitor C1 is Vc1, the voltage of the second capacitor C2 is Vc2, the voltage at point a is VA, and the voltage at point D is VD.

Assuming VLED1 ═ VLED2 ═ VLED3 ═ VLED4, VLED1 ═ VLED2 ═ VLED3 ═ VLED4 ═ 110 volts, Vout2 ═ Vc2 ═ 80 volts, Vout1 ═ 150 volts when the four LED lamps pass rated currents; at this time, VA is 110 v, VD is 110-.

When the constant current chip 111 controls the current control element Q2 to decrease the current passing through the backlight source 200, the voltage drop thereof is decreased due to the characteristics of the LEDs themselves, and when the current is decreased to VLED1 ═ VLED2 ═ VLED3 ═ VLED4 ═ 100 volts, if Vout1 and Vout2 are kept unchanged, VD ═ 50 volts, and Vc1 ═ 50 volts. It can be seen that when the voltage of the LED lamp varies by 10 volts, since the first/second current loop includes two LED lamps, the voltage control element Q1 controls the first capacitor C1 to vary by 20 volts.

Based on this, when the constant current chip 111 controls the current change of the LED lamp to change its voltage by 10 volts, the constant current chip 111 may control the voltage of the first capacitor C1 by 20 volts through the voltage control element Q1, so that the first capacitor C1 may compensate the voltage change of the LED lamp to maintain the first voltage and the second voltage unchanged.

The constant current chip 111 of the embodiment of the application can control the current control element Q2 and the voltage control element Q1 at the same time, and the constant current chip 111 can control the brightness change of the backlight source 200 and can control the voltage changing module 140 to change the voltage. Based on this, the driving circuit 100 can realize two control logics through the constant current chip 111, the constant current chip 111 realizes multiplexing, and the structure of the driving circuit 100 is simpler and the cost is lower.

It should be noted that, the above is only an exemplary example of the driving circuit 100 controlling the voltage transformation module 140, and the solution of the embodiment of the present application is not limited thereto, for example, the driving circuit 100 may control the voltage transformation module 140 through another controller, and the embodiment of the present application does not limit the specific manner in which the driving circuit 100 controls the voltage transformation module 140, and all solutions that can implement the control of the voltage transformation module 140 are within the scope of the embodiment of the present application.

Referring to fig. 5 to 8 again, the driving circuit 100 may further include a converter 150 and a feedback device 160.

The inverter 150 may be electrically connected to the transformer 120, and the inverter 150 may supply the first voltage and the second voltage to the transformer 120 so that the transformer 120 may operate normally. It will be appreciated that the converter 150 may be an LLC half-bridge resonator.

One end of the feedback 160 may be electrically connected to the inverter 150, and the other end of the feedback 160 may be electrically connected to the second winding 122, for example, the other end of the feedback 160 may be electrically connected between the second diode D2 and the second capacitor C2, so as to achieve indirect electrical connection to the second winding 122. The feedback device 160 may detect the voltage of the second capacitor C2, and the voltage of the second capacitor C2 is equal to the second voltage of the second winding 122, and the second voltage is a multiple of the first voltage, so that the feedback device 160 may feed back the first voltage and the second voltage of the converter 150 to the converter 150 by obtaining the voltage of the second capacitor C2, so as to facilitate the control of the converter 150 on the voltage of the transformer 120.

The driving circuit 100 of the embodiment of the present application includes the converter 150 and the feedback device 160, the converter 150 may control the voltage of the transformer 120 according to the first voltage and the second voltage obtained by the feedback device 160, and the converter 150 may make the operating state of the transformer 120 more stable.

Based on the structure of the driving circuit 100, a display device 10 is further provided in the present embodiment, please refer to fig. 9, and fig. 9 is a connection diagram of the display device 10 provided in the present embodiment. The display device 10 may be an LED display screen, the display device 10 may include a driving circuit 100 and a backlight source 200, the driving circuit 100 may be electrically connected to the backlight source 200, and the driving circuit 100 may control the brightness of the backlight source 200.

It is understood that the display device 10 may also include other structures, such as a light source, a glass plate, various optical elements, etc., which are described in the related art and not described in detail herein.

It is to be understood that the display device 10 may be a display device of a smart phone, a smart television, a wearable electronic device, a VR device, and the like, which is not limited in this embodiment of the application.

In the display device 10 of the embodiment of the application, the voltage transformation module 140 of the driving circuit 100 may change the voltage of the backlight source 200 to make the first voltage of the first winding 121 and the second voltage of the second winding 122 in the constant voltage range, and the operating frequency of the transformer 120 may also be in the constant frequency range, so that the display device 10 does not frequently change the control instruction for the transformer 120, and the control of the transformer 120 by the display device 10 is more stable.

It is to be understood that, in the description of the present application, terms such as "first", "second", and the like are used merely to distinguish similar objects and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated.

The driving circuit and the display device provided in the embodiments of the present application are described in detail above. The principles and implementations of the present application are described herein using specific examples, which are presented only to aid in understanding the present application. Meanwhile, for those skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. A driver circuit, comprising:

2. The driving circuit of claim 1, wherein the voltage transformation module is a buck converter circuit.

3. The driving circuit of claim 2, wherein the second winding includes a first port and a second port, the second port being grounded; the voltage transformation module comprises:

4. The driving circuit according to claim 3, further comprising:

5. The driving circuit of claim 1, wherein the backlight source comprises:

6. The driving circuit of claim 5, wherein the backlight source further comprises:

7. The drive circuit of claim 6, wherein the first winding includes a third port and a fourth port; the pressure supply module includes:

one end of the third capacitor is electrically connected with the third port;

8. The drive circuit according to any one of claims 1 to 7, further comprising:

9. The drive circuit according to any one of claims 1 to 7, wherein the constant current module includes:

a current control element electrically connected to the backlight source; and

10. A display device comprising the driver circuit according to any one of claims 1 to 9.