CN112564486B

CN112564486B - Display device

Info

Publication number: CN112564486B
Application number: CN201910919848.7A
Authority: CN
Inventors: 辛惠莹; 高宽志
Original assignee: Hisense Visual Technology Co Ltd
Current assignee: Hisense Visual Technology Co Ltd
Priority date: 2019-09-26
Filing date: 2019-09-26
Publication date: 2022-04-22
Anticipated expiration: 2039-09-26
Also published as: WO2021056956A1; CN112564486A

Abstract

The embodiment of the invention provides a display device. The display device comprises a display panel, a driving board and a power board, wherein the power board of the display device is provided with a rectifying circuit, a surge detection circuit, a control circuit and a resonant circuit, the resonant circuit comprises a power switch, the voltage of the rectifying circuit is detected by using the surge detection circuit, and when the voltage of the rectifying circuit exceeds a preset voltage, the control circuit is controlled, so that the control circuit controls the state of the power switch in the resonant circuit, the resonant circuit stops generating ringing voltage, the voltage applied to the power switch is reduced, the power switch is protected, and the safety performance of the display device is improved.

Description

Display device

Technical Field

The embodiment of the invention relates to the technical field of circuits, in particular to a display device.

Background

The surge refers to an overload voltage or current which is far greater than a steady-state voltage or current peak value and is generated at the moment of power-on or under the condition that a circuit is abnormal, and the overload voltage or current is likely to cause the circuit to be burnt out at the moment of the surge, such as PN junction capacitor breakdown, resistance burning-out and the like. In the electronic equipment, a surge voltage is generated at the moment when a switching power supply of the electronic equipment is turned on, so that a circuit and a device of the electronic equipment are damaged, and the electronic equipment is irreversibly damaged when the circuit and the device are seriously damaged.

In the prior art, a voltage dependent resistor or a gas discharge tube is usually arranged at a port of an input end of a switching power supply circuit to absorb surge voltage, so that a post-stage device at the port of the input end in the switching power supply circuit is prevented from being impacted by too high surge. However, the varistor or the gas discharge tube can absorb and suppress only a limited surge voltage, and when the surge voltage is much higher than the operating voltage of the varistor or the gas discharge tube, a high surge voltage (i.e., residual voltage) is present even after the absorption and suppression by the varistor or the gas discharge tube.

However, these residual voltages can increase the voltage of the high voltage electrolytic capacitor (i.e. the bus voltage Vm) of the switching power supply circuit, and the power switch in the switching power supply circuit is electrically connected to the inductor capacitor, wherein the power switch may be, for example, a Metal-Oxide-Semiconductor Field-Effect Transistor (MOS) Transistor, an Insulated Gate Bipolar Transistor (IGBT), or the like. Therefore, the voltage applied to the power switch is Vm + Vs, and if the bus voltage Vm is very high under the action of residual voltage, the voltage applied to the power switch is far higher than the upper limit of the normal operating voltage of the power switch, so that the power switch is damaged, and in case of serious safety accidents are caused.

Disclosure of Invention

The embodiment of the invention provides a display device, which can detect the voltage of a rectifying circuit on a power panel of the display device through a surge detection circuit on the power panel, and can stop a power switch to protect the power switch when the detected voltage is the surge voltage, so that the safety performance of the display device is improved.

In a first aspect, an embodiment of the present invention provides a display device, including:

a display panel;

a driving board for driving the display panel;

the power panel is provided with a rectifying circuit, a surge detection circuit, a control circuit and a resonant circuit, and the resonant circuit comprises a power switch; wherein the content of the first and second substances,

the rectifier circuit is used for rectifying the input alternating current into direct current and transmitting the direct current to the resonance circuit;

the resonance circuit is used for generating a driving pulse signal and ringing voltage under the action of the direct current and transmitting the driving pulse signal to the driving board, and the ringing voltage acts on the power switch;

the surge detection circuit is used for detecting the voltage of the rectifying circuit, and outputting a first control signal to the control circuit when the voltage of the rectifying circuit is greater than or equal to a preset voltage, wherein the first control signal is used for enabling the control circuit to output a second control signal to the power switch, and the second control signal is used for controlling the power switch to be in a state capable of enabling the resonant circuit to stop generating ringing voltage;

the control circuit is used for receiving the first control signal and outputting a second control signal to the power switch according to the first control signal;

the resonance circuit is used for stopping generating the ringing voltage after the power switch receives the second control signal so as to reduce the voltage applied to the power switch.

In some possible embodiments, the surge detection circuit includes: the first diode is electrically connected with the live wire and the detection sub-circuit respectively, the second diode is electrically connected with the zero wire and the detection sub-circuit respectively, and the detection sub-circuit is also electrically connected with the rectifying circuit and the control circuit respectively;

the first diode is used for controlling the detection sub-circuit to detect a first voltage between the live wire and the zero line when the voltage of the live wire is greater than the voltage of the zero line;

the second diode is used for controlling the detection sub-circuit to detect a first voltage between the live wire and the zero wire when the voltage of the zero wire is greater than the voltage of the live wire;

the detection sub-circuit is used for detecting a first voltage between the live wire and the zero wire, and when the first voltage is greater than or equal to a first preset voltage, a first control signal is continuously sent to the control circuit until the first voltage is less than the first preset voltage.

In some possible embodiments, the surge detection circuit includes: the detection sub-circuit is electrically connected with the rectifying circuit and the control circuit respectively;

the detection sub-circuit is used for detecting a second voltage of the direct current output by the rectification circuit, and when the second voltage is greater than or equal to a second preset voltage, a first control signal is continuously sent to the control circuit until the second voltage is less than the second preset voltage.

In some possible embodiments, the detection sub-circuit comprises: the circuit comprises a first resistor, a second resistor and a first capacitor, wherein one end of the first resistor is electrically connected with a first diode and a second diode respectively, the other end of the first resistor is electrically connected with one end of the second resistor, one end of the second resistor is also electrically connected with a control circuit, the other end of the second resistor is connected with a rectifying circuit, and the first capacitor is connected with the second resistor in parallel;

the first resistor and the second resistor are used for dividing a first voltage to detect the size of the first voltage according to the divided voltage, and when the divided voltage indicates that the first voltage is greater than or equal to a preset first voltage, a first control signal is sent to the control circuit;

the second resistor and the first capacitor are used for controlling the time length of sending the first control signal to the control circuit.

In some possible embodiments, the detection sub-circuit comprises: the rectifier circuit comprises a first resistor, a second resistor and a first capacitor, wherein one end of the first resistor is electrically connected with one end of the rectifier circuit for outputting direct current, the other end of the first resistor is electrically connected with one end of the second resistor, the other end of the second resistor is electrically connected with the other end of the rectifier circuit for outputting direct current, and the first capacitor is connected with the second resistor in parallel;

the first resistor and the second resistor are used for dividing a second voltage to detect the size of the second voltage according to the divided voltage, and when the divided voltage indicates that the second voltage is greater than or equal to a preset second voltage, a first control signal is sent to the control circuit;

In some possible embodiments, the control circuit comprises: the control sub-circuit is electrically connected with the detection sub-circuit and the first pin of the control chip respectively, and the second pin of the control chip is electrically connected with the power switch;

the control sub-circuit is configured to receive the first control signal, and send a third control signal to the control chip through the first pin according to the first control signal, where the third control signal is used to instruct the control chip to output a second control signal to the power switch through the second pin;

the control chip is used for outputting a second control signal to the power switch through the second pin according to the third control signal when receiving the third control signal; and controlling the state of the power switch when the third control signal is not received.

In some possible embodiments, the control circuit comprises: the control sub-circuit is electrically connected with the detection sub-circuit and the power switch respectively, and a second pin of the control chip is electrically connected with the power switch;

the control sub-circuit is used for receiving the first control signal and outputting a second control signal to the power switch according to the first control signal;

and the control chip is used for controlling the state of the power switch when the control sub-circuit does not output a second control signal to the power switch.

In some possible embodiments, the control sub-circuit comprises: the controllable element is electrically connected with the detection sub-circuit and the first pin of the control chip respectively;

the controllable element is configured to receive a first control signal sent by the detection sub-circuit, and send the third control signal to the first pin of the control chip according to the first control signal, so that the second pin of the control chip sends the second control signal to the power switch.

In some possible embodiments, the control sub-circuit comprises controllable elements electrically connected to the detection sub-circuit and to the power switch, respectively;

the controllable element is used for receiving a first control signal sent by the detection sub-circuit and sending a second control signal to the power switch according to the first control signal.

In some possible embodiments, the controllable element is any one of: NPN type triode, PNP type triode, N type MOS pipe, P type MOS pipe.

The embodiment of the invention provides a display device which comprises a display panel, a driving board and a power board, wherein a rectifying circuit, a surge detection circuit, a control circuit and a resonance circuit (namely a surge protection circuit) are arranged on the power board of the display device, the voltage of the rectifying circuit is detected by using the surge detection circuit, and when the voltage of the rectifying circuit exceeds the preset voltage, the control circuit is controlled to enable the control circuit to control the state of a power switch in the resonance circuit, so that the resonance circuit stops generating ringing voltage, the voltage applied to the power switch is reduced, the power switch is protected, and the safety performance of the display device is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a display device provided with an independent power board according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a circuit on a power board according to an embodiment of the invention;

fig. 3 is a schematic structural diagram of a surge protection circuit according to another embodiment of the present invention;

fig. 4 is a schematic structural diagram of a surge protection circuit according to another embodiment of the present invention;

fig. 5 is a schematic structural diagram of a surge protection circuit according to another embodiment of the present invention;

fig. 6 is a schematic structural diagram of a surge protection circuit according to another embodiment of the present invention;

fig. 7 is a schematic structural diagram of a surge protection circuit according to another embodiment of the present invention;

fig. 8 is a schematic structural diagram of a surge protection circuit according to another embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. 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 invention.

Fig. 1 is a schematic structural diagram of a display device provided with an independent power board according to an embodiment of the present invention. As shown in fig. 1, a display device, such as a television, includes: the display panel is used for presenting pictures for a user; the driving board is used for driving the display panel to enable the display panel to display pictures; the power panel is used for supplying power to elements inside the display device. The display device may further include a main board, a rear case, a base, and the like, which are not shown in fig. 1.

An input port circuit is arranged on the power panel and connected with the mains supply through a plug. The power panel needs to convert ac power into dc power required by the components inside the display device. The input port circuit can generate surge voltage in a power supply circuit of the display device at the moment of connection and disconnection of the plug and the mains supply, and damage components inside the display device. Therefore, in the embodiment of the present invention, the surge detection circuit 200 is disposed on the power board to detect whether a surge voltage is generated in the power supply circuit, so as to prevent the display device from being damaged by the surge voltage.

Fig. 2 is a schematic structural diagram of a circuit on a power board according to an embodiment of the present invention, and as shown in fig. 2, the power board includes: a rectifier circuit 100, a surge detection circuit 200, a control circuit 300, and a resonant circuit 400, wherein the resonant circuit 400 includes a power switch (not shown in fig. 2). In the embodiment of the present invention, the circuit composed of the rectifier circuit 100, the surge detection circuit 200, the control circuit 300, and the resonance circuit 400 can detect whether a surge voltage exists in the circuit, and when the surge voltage exists in the circuit, the resonance circuit 400 stops operating to protect the power board and thus the display device, so the circuit composed of the rectifier circuit 100, the surge detection circuit 200, the control circuit 300, and the resonance circuit 400 can be referred to as a surge protection circuit in the embodiment of the present invention. Wherein, in the surge protection circuit,

the rectifier circuit 100 rectifies an input ac power into a dc power and supplies the dc power to the resonant circuit 400.

And the resonant circuit 400 is used for generating a driving pulse signal and a ringing voltage under the action of direct current, transmitting the driving pulse signal to the driving plate, and applying the ringing voltage to the power switch.

The surge detection circuit 200 is configured to detect a voltage of the rectifier circuit 100, and output a first control signal to the control circuit 300 when the voltage of the rectifier circuit 100 is greater than or equal to a preset voltage, where the first control signal is used to enable the control circuit 300 to output a second control signal to the power switch, and the second control signal is used to control the power switch to be in a state where the resonance circuit 400 can stop generating a ringing voltage.

The control circuit 300 is configured to receive the first control signal and output a second control signal to the power switch according to the first control signal.

The resonant circuit 400 is configured to stop generating the ringing voltage after the power switch receives the second control signal, so as to reduce the voltage applied to the power switch.

As shown in fig. 1, the surge protection circuit provided in this embodiment is structurally configured such that an input port circuit is connected to an external power supply (e.g., commercial power) via a plug to supply power to a display device, the input port circuit is connected to a rectifier circuit 100 to rectify ac power into dc power, the rectifier circuit 100 is electrically connected to a surge detection circuit 200 and a resonance circuit 400, respectively, the surge detection circuit 200 is electrically connected to a control circuit 300, and the control circuit 300 is electrically connected to the resonance circuit 400.

The working principle of the surge protection circuit provided by the embodiment is as follows:

the input port circuit obtains electric power by being connected to an external power supply, and since the power supplied from the external power supply is ac power, the rectifier circuit 100 rectifies the ac power into dc power. The rectifier circuit 100 provides a direct current to the resonant circuit 400, and since the resonant circuit 400 includes a power switch and an inductor capacitor, the resonant circuit 400 generates a ringing voltage when the power switch is switched on and off, and thus, the voltage applied to the power switch includes the voltage of the direct current output by the rectifier circuit 100 and the ringing voltage.

If surge voltage is generated in the input port circuit at the moment of power-on, the voltage of the direct current output by the rectifying circuit 100 is increased, and therefore the voltage applied to the power switch is increased and is higher than the upper limit of the voltage when the power switch normally works, so that the power switch is damaged, and potential safety hazards exist. Therefore, the surge detection circuit 200 is provided to be connected to the rectifier circuit 100, and the voltage of the rectifier circuit 100 is detected by the surge detection circuit 200, wherein the surge detection circuit 200 may directly detect the voltage of the rectifier circuit 100 or indirectly detect the voltage of the rectifier circuit 100. When the voltage is detected to exceed the preset voltage, a first control signal is output to the control circuit 300, and after the control circuit 300 receives the first control signal, a second control signal is output to the power switch according to the first control signal, wherein the second control signal is used for controlling the state of the power switch, so that the resonance circuit 400 stops generating the ringing voltage, and the voltage applied to the power switch is reduced.

In this embodiment, the display device includes a display panel, a driving board, and a power board, wherein the power board of the display device is provided with a rectifying circuit, a surge detection circuit, a control circuit, and a resonant circuit (i.e., a surge protection circuit), the surge detection circuit is used to detect the voltage of the rectifying circuit, and when the voltage of the rectifying circuit exceeds a preset voltage, the control circuit is controlled to control the state of a power switch in the resonant circuit, so that the resonant circuit stops generating a ringing voltage, the voltage applied to the power switch is reduced, and the power switch is protected, thereby improving the safety performance of the display device.

Fig. 3 is a schematic structural diagram of a surge protection circuit according to another embodiment of the present invention. As shown in fig. 3, based on the embodiment shown in fig. 2, the surge detection circuit 200 includes: a first diode D1 and a second diode D2, and a detection sub-circuit 230. The first diode D1 is electrically connected to the live wire and the detection sub-circuit 230, the second diode D2 is electrically connected to the neutral wire and the detection sub-circuit 230, and the detection sub-circuit 230 is further electrically connected to the rectification circuit 100 and the control circuit 300.

The first diode D1 is used for controlling the detection sub-circuit 230 to detect the first voltage between the live wire and the neutral wire when the voltage of the live wire is larger than the voltage of the neutral wire.

And a second diode D2 for controlling the detection sub-circuit 230 to detect the first voltage between the live line and the neutral line when the voltage of the neutral line is greater than the voltage of the live line.

The detection sub-circuit 230 is configured to detect a first voltage between the live line and the neutral line, and when the first voltage is greater than or equal to a first preset voltage, continuously send a first control signal to the control circuit 300 until the first voltage is less than the first preset voltage.

In this embodiment, the anode of the first diode D1 is electrically connected to the hot wire, the anode of the second diode D2 is electrically connected to the neutral wire, and the cathode of the first diode D1 and the cathode of the second diode D2 are electrically connected to the same end of the detection sub-circuit 230. The output end of the rectifying circuit 100 includes a positive output end and a negative output end, and the detection sub-circuit 230 is further electrically connected to one of the output ends of the rectifying circuit 100 and the control circuit 300, respectively.

Because the point between live wire and the zero line is the alternating current, when the electric current flows to the zero line by the live wire, the flow direction of electric current is: live wire → first diode D1 → detection subcircuit 230 → neutral wire, when current flows from the neutral wire to the live wire, the current flows in the following direction: neutral → second diode D2 → detection subcircuit 230 → live. Since the voltage between the live wire and the neutral wire is related to whether there is a surge voltage in the circuit, the detection sub-circuit 230 may detect the voltage between the live wire and the neutral wire, and the detection of the voltage between the live wire and the neutral wire may be, for example, peak voltage detection or average voltage detection, where in the embodiment of the present invention, the voltage between the live wire and the neutral wire is referred to as a first voltage. When the current flows to the live wire or the neutral wire through the detection sub-circuit 230, the current flows to the live wire or the neutral wire through the rectification circuit 100, which may specifically refer to fig. 5 and 6, and details are not repeated here. When the detection sub-circuit 230 detects that the first voltage is higher than the first preset voltage, it indicates that the surge voltage in the circuit is higher, and the control circuit 300 needs to be controlled to enable the control circuit 300 to control the state of the power switch in the resonant circuit 400, so that the resonant circuit 400 stops generating the ringing voltage, and the voltage borne by the power switch is reduced.

In this embodiment, among the surge protection circuit, detect the voltage between live wire and the zero line through surge detection circuitry, according to the voltage between live wire and the zero line, change power switch's state to make resonant circuit stop producing ringing voltage, reduced the voltage on the power switch, protection power switch improves display device's security.

Fig. 4 is a schematic structural diagram of a surge protection circuit according to another embodiment of the present invention. As shown in fig. 3, based on the embodiment shown in fig. 2, the surge detection circuit 200 includes: the detection sub-circuit 240. The detection sub-circuit 240 is electrically connected to the rectifier circuit 100 and the control circuit 300, respectively. It should be noted that the internal structure of the detection sub-circuit 240 shown in the present embodiment may be the same as or different from the internal structure of the detection sub-circuit 230 shown in the embodiment of fig. 3, and the detection sub-circuit 230 mentioned below may be replaced by the detection sub-circuit 240.

The detection sub-circuit 240 is configured to detect a second voltage of the direct current output by the rectification circuit 100, and when the second voltage is greater than or equal to a second preset voltage, continuously send the first control signal to the control circuit 300 until the second voltage is less than the second preset voltage.

In this embodiment, the output end of the rectifying circuit 100 includes a positive output end and a negative output end, a direct current is provided between the positive output end and the negative output end, and the voltage of the direct current is a high-voltage electrolytic capacitor voltage (i.e., a bus voltage). When the detection sub-circuit 240 detects that the second voltage is higher than the second preset voltage, it indicates that the surge voltage in the circuit is higher, and the control circuit 300 needs to be controlled to enable the control circuit 300 to control the state of the power switch in the resonant circuit 400, so that the resonant circuit 400 stops generating the ringing voltage, and the voltage borne by the power switch is reduced.

In this embodiment, in the surge protection circuit, the voltage of the direct current output by the rectification circuit can be detected by the surge detection circuit, and the state of the power switch is changed according to the voltage of the direct current, so that the resonance circuit stops generating the ringing voltage, the voltage on the power switch is reduced, the power switch is protected, and the safety of the display device is improved.

In some possible embodiments, based on the embodiment of the surge detection circuit 200 as shown in any of fig. 3 and 4, as shown in fig. 3, the control circuit 300 includes: the power switch comprises a control sub-circuit 310 and a control chip 320, wherein the control sub-circuit 310 is electrically connected with first pins of the detection sub-circuit 230 and the control chip 320 respectively, and a second pin of the control chip 320 is electrically connected with the power switch.

The control sub-circuit 310 is configured to receive the first control signal, and send a third control signal to the control chip 320 through the first pin according to the first control signal, where the third control signal is used to instruct the control chip 320 to output a second control signal to the power switch through the second pin.

The control chip 320 is configured to output a second control signal to the power switch through the second pin according to the third control signal when receiving the third control signal; and controlling the state of the power switch when the third control signal is not received.

In this embodiment, one end of the control sub-circuit 310 is electrically connected to the detection sub-circuit 230, the other end is electrically connected to the first pin of the control chip 320, and the second pin of the control chip 320 is electrically connected to the power switch. Therefore, the first control signal sent by the detection sub-circuit 230 can be received, and the third control signal can be output to the control chip 320 through the first pin of the control chip 320 according to the first control signal. The first pin of the control chip 320 may be, for example, a pin having a fixed function, such as a dead time control pin, a feedback control pin, an overcurrent control pin, a soft start pin, and an overvoltage control pin, so that after the first pin receives the third control signal, the second pin of the control chip 320 outputs a second control signal to the power switch through hardware control; or, the function of each pin in the control chip 320 is controlled by software, and after detecting that the first pin receives the third control signal, the second pin is controlled to output the second control signal to the power switch, so as to control the state of the power switch, and stop the resonant circuit 400 from generating the ringing voltage. In addition, when the first pin of the control chip 320 does not receive the third control signal, that is, when there is no surge voltage in the circuit or the surge voltage is low, the control chip 320 controls the state of the power switch through the second pin, so that the display device operates normally.

In the embodiment, in the surge protection circuit, the control sub-circuit is electrically connected between the detection sub-circuit and the control chip, the control chip is electrically connected with the power switch, and when the detection sub-circuit detects that the surge voltage is too high, the control chip controls the power switch through the control sub-circuit, so that the resonance circuit stops generating the ringing voltage, the power switch is protected, and the safety of the display device is improved.

In some possible embodiments, based on the embodiment of the surge detection circuit 200 as shown in any one of fig. 3 and fig. 4, as shown in fig. 4, the control circuit 300 includes: the detection circuit comprises a control sub-circuit 310 and a control chip 320, wherein the control sub-circuit 310 is electrically connected with the detection sub-circuit 240 and the power switch respectively, and a second pin of the control chip 320 is electrically connected with the power switch. It should be noted that the internal structure of the control sub-circuit 310 in the present embodiment may be the same as or different from the internal structure of the control sub-circuit 310 shown in the embodiment of fig. 3, and the control sub-circuit 310 mentioned below may be replaced by the control sub-circuit 310.

The control sub-circuit 310 is configured to receive the first control signal and output a second control signal to the power switch according to the first control signal.

And the control chip 320 is configured to control the state of the power switch when the control sub-circuit 310 does not output the second control signal to the power switch.

In this embodiment, one end of the control sub-circuit 310 is electrically connected to the detection sub-circuit 240, and the other end is electrically connected to the power switch, so that the control sub-circuit 310 can receive the first control signal sent by the detection sub-circuit 240, and thus directly send the second control signal to the power switch according to the first control signal, so that the power switch is in a state that the resonance circuit 400 can stop generating the ringing voltage. The pin of the control chip 320 is electrically connected to the power switch, for example, is also the second pin, and when the control sub-circuit 310 does not output the second control signal to the power switch, the state of the power switch is controlled, and at this time, the state of the power switch is the state during normal operation.

In this embodiment, in the control circuit of the surge protection circuit, the control sub-circuit is electrically connected between the detection sub-circuit and the power switch, and after receiving the first control signal, the control sub-circuit directly outputs the second control signal to the power switch to control the state of the power switch, so that the resonance circuit stops generating the ringing voltage, thereby protecting the power switch and improving the safety of the display device.

Fig. 5 is a schematic structural diagram of a surge protection circuit according to another embodiment of the present invention. Based on the embodiments shown in fig. 3 and/or fig. 4, as shown in fig. 5, the detection sub-circuit 230 includes: the rectifier circuit comprises a first resistor R1, a second resistor R2 and a first capacitor C1, wherein one end of the first resistor R1 is electrically connected with a first diode D1 and a second diode D2 respectively, the other end of the first resistor R1 is electrically connected with one end of a second resistor R2, one end of the second resistor R2 is further electrically connected with the control circuit 300, the other end of the second resistor R2 is connected with the rectifier circuit 100, and the first capacitor C1 is connected with a second resistor R2 in parallel. The control sub-circuit 310 includes: and the controllable elements are electrically connected with the detection subcircuit 230 and the first pin of the control chip 320 respectively.

The first resistor R1 and the second resistor R2 are configured to divide the first voltage to detect a magnitude of the first voltage according to the divided voltage, and send a first control signal to the control circuit 300 when the divided voltage indicates that the first voltage is greater than or equal to a preset first voltage.

A second resistor R2 and a first capacitor C1 for controlling the duration of the first control signal sent to the control circuit 300.

The controllable element is configured to receive the first control signal sent by the detection sub-circuit 230, and send a third control signal to the first pin of the control chip 320 according to the first control signal, so that the second pin of the control chip 320 sends a second control signal to the power switch.

In this embodiment, the controllable element may be, for example, an NPN transistor, a PNP transistor, an N-type MOS transistor, and a P-type MOS transistor, where the P-type MOS transistor VI is taken as an example for description in this embodiment. The power switch will be described by taking a P-type MOS transistor V2 as an example.

Taking the example that the voltage of the live line (denoted by L in the figure) is higher than the voltage of the zero line (denoted by N in the figure), the current flows in the following steps: the live wire → the first diode D1 → the first resistor R1 → the second resistor R2 → VB1 → the zero line, the first resistor R1 and the second resistor R2 are used for dividing the first voltage, because the a point in the circuit is electrically connected with the gate of the P-type MOS transistor VI, under normal circumstances, the P-type MOS transistor VI is turned on, the first pin of the control chip 320 is connected with a high level, when the first voltage is greater than or equal to the first preset voltage, the voltage at the a point is also increased, that is, the voltage at the gate of the P-type MOS transistor VI is increased, which is equivalent to sending the first control signal to the P-type MOS transistor VI. After the gate voltage of the P-type MOS transistor VI rises, the P-type MOS transistor VI is turned off, at this time, the first pin of the control chip 320 is connected to a low level, which is equivalent to the P-type MOS transistor VI sending a third control signal to the first pin of the control chip 320, and after receiving the third control signal, the first pin of the control chip 320 outputs a high level to the P-type MOS transistor V2 through the second pin, which is equivalent to sending a second control signal to the power switch, so that the P-type MOS transistor V2 is switched from a conducting state to a turning-off state, and thus the P-type MOS transistor V2 and the inductive capacitor T1 do not generate a ringing voltage.

The first capacitor C1 is connected in parallel with the second resistor R2, and when the input port circuit is connected to an external power supply to generate surge voltage in the circuit, the first capacitor C1 is in a charging state, and the P-type MOS transistor VI is in a cut-off state. When the surge voltage is gradually reduced, the first capacitor C1 is in a discharging state, which can reduce the speed of voltage reduction at point a, and increase the duration of the P-type MOS transistor VI in the off state, thereby increasing the duration of the P-type MOS transistor V2 in the off state. In addition, when the resistance of the first resistor R1 is fixed, the larger the resistance of the second resistor R2 is, the higher the voltage at the point a is, the longer the time period that the P-type MOS transistor VI is in the off state is, so that the longer the time period that the P-type MOS transistor V2 is in the off state is. Therefore, by adjusting the parameter values of the first capacitor C1 and the second resistor R2, the time duration for sending the first control signal to the control circuit 300 (i.e., the P-type MOS transistor VI) can be controlled, and therefore the time duration for the P-type MOS transistor V2 to be in the off state can be controlled.

The surge protection circuit provided by the embodiment can control the state of the power switch, so that the resonance circuit cannot generate ringing voltage, the voltage on the P-type MOS tube (namely the power switch) is reduced, the damage of the power switch is avoided, and the safety of the display device is improved. The duration that the resonant circuit cannot generate ringing voltage can be adjusted through the first capacitor and the second resistor in the detection sub-circuit, and the flexibility of the surge protection circuit is improved.

Fig. 6 is a schematic structural diagram of a surge protection circuit according to another embodiment of the present invention. Based on the embodiments shown in fig. 3 and/or fig. 4, as shown in fig. 6, the detection sub-circuit 230 includes: the detection sub-circuit 230 includes: the rectifier circuit comprises a first resistor R1, a second resistor R2 and a first capacitor C1, wherein one end of the first resistor R1 is electrically connected with one end of the rectifier circuit 100, which outputs direct current, the other end of the first resistor R1 is electrically connected with one end of the second resistor R2, the other end of the second resistor R2 is electrically connected with the other end of the rectifier circuit 100, which outputs direct current, and the first capacitor C1 is connected with the second resistor R2 in parallel. The control sub-circuit 310 includes controllable elements that are electrically connected to the detection sub-circuit 230 and the power switch, respectively.

And the first resistor R1 and the second resistor R2 are configured to divide the second voltage to detect the magnitude of the second voltage according to the divided voltage, and send a first control signal to the control circuit 300 when the divided voltage indicates that the second voltage is greater than or equal to a preset second voltage.

And a controllable element, configured to receive the first control signal sent by the detection sub-circuit 230, and send a second control signal to the power switch according to the first control signal.

In this embodiment, the controllable element is exemplified by a P-type MOS transistor V1. The power switch will be described by taking an N-type MOS transistor V3 as an example.

For example, one end of the first resistor R1 is electrically connected to the positive input terminal of the rectifier circuit 100, the other end is electrically connected to one end of the second resistor R2, the other end of the second resistor R2 is electrically connected to the negative input terminal of the rectifier circuit 100, so that the first resistor R1 and the second resistor R2 divide the second voltage, the point a in the circuit is electrically connected to the gate of the P-type MOS transistor VI, and the gate of the N-type MOS transistor V3 is electrically connected to the drain of the P-type MOS transistor VI and the second pin of the control chip 320. Under normal conditions, the P-type MOS transistor VI is turned on, so that the voltage of the gate of the N-type MOS transistor V3 is the sum of the voltage at the point a and the voltage provided by the control chip 320 through the second pin. When the second voltage is greater than or equal to the second preset voltage, the voltage at the point a also rises, that is, the gate voltage of the P-type MOS transistor VI rises, which is equivalent to sending the first control signal to the P-type MOS transistor VI. After the gate voltage of the P-type MOS transistor VI rises, the P-type MOS transistor VI is turned off, and no voltage is supplied to the gate of the N-type MOS transistor V3, which is equivalent to the P-type MOS transistor VI sending a second control signal to the N-type MOS transistor V3. At this time, the voltage of the gate of the N-type MOS transistor V3 is only the voltage provided by the control chip 320 through the second pin, that is, the voltage of the gate of the N-type MOS transistor V3 decreases, and the N-type MOS transistor V3 switches from the on state to the off state, so that the ringing voltage is not generated by the N-type MOS transistor V3 and the inductor capacitor T1.

The duration of the N-type MOS transistor V3 in the off state can be adjusted by adjusting the parameter values of the first capacitor C1 and/or the second resistor R2, and the specific principle can refer to the above description, which is not repeated herein.

The surge protection circuit provided by the embodiment detects the state of the controllable element controlled by the sub-circuit according to the voltage of the direct current output by the rectifying circuit, and then the controllable element directly controls the state of the power switch, so that the resonance circuit stops generating the ringing voltage, the circuit design is simplified, when the surge voltage is generated, the ringing voltage is stopped as fast as possible, the power switch is protected, and the safety of the display device is improved.

It should be noted that the connection manner of the surge detection circuit 200 shown in fig. 5 in the surge protection circuit may be replaced with the connection manner of the surge detection circuit 200 shown in fig. 6 in the surge protection circuit, as shown in fig. 7. The connection manner of the control circuit 300 shown in fig. 5 in the surge protection circuit can replace the connection manner of the control circuit 300 in the surge protection circuit shown in fig. 6, as shown in fig. 8.

As shown in fig. 5 to 8, since the safety capacitor C2 is provided in the input port circuit, when the input port circuit is disconnected from the external power supply, it is necessary to discharge the voltage of the safety capacitor C2 to a safe value (for example, 30V) or less within a safe time (for example, 2s), and therefore, the rectifier circuit 100 is provided with the third resistor R3 and the fourth resistor R4, the third resistor R3 and the fourth resistor R4 are connected in series and are connected between the live line and the live line, and the voltage of the safety capacitor C2 is discharged through the third resistor R3 and the fourth resistor R4. When the surge detection circuit 200 is connected to the surge protection circuit in the manner shown in fig. 5 and 7, the rectifier circuit 100 may not be provided with the third resistor R3 and the fourth resistor R4, and the voltage of the safety capacitor C2 may be discharged through the first resistor R1 and the second resistor R2, and at this time, the current flows in the following manner: live wire → first diode D1 → first resistor R1 → second resistor R2 → VB1 → neutral wire, or neutral wire → second diode D2 → first resistor R1 → second resistor R2 → VB1 → live wire.

It should be noted that the surge protection circuits provided in fig. 5-8 can also be used as undervoltage or overvoltage protection circuits.

Those of ordinary skill in the art will understand that: all or a portion of the steps of implementing the above-described method embodiments may be performed by hardware associated with program instructions. The program may be stored in a computer-readable storage medium. When executed, the program performs steps comprising the method embodiments described above; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A display device, comprising:

a display panel;

a driving board for driving the display panel;

the surge detection circuit is used for detecting the voltage of the rectifying circuit, and outputting a first control signal to the control circuit when the voltage of the rectifying circuit is greater than or equal to a preset voltage, wherein the first control signal is used for enabling the control circuit to output a second control signal to the power switch, and the second control signal is used for controlling the power switch to be in a state capable of enabling the resonant circuit to stop generating ringing voltage; the surge detection circuit at least comprises a detection sub-circuit;

the resonance circuit is used for stopping generating the ringing voltage after the power switch receives the second control signal so as to reduce the voltage applied to the power switch;

if the control circuit comprises: the control sub-circuit is electrically connected with the detection sub-circuit and the first pin of the control chip respectively, and the second pin of the control chip is electrically connected with the power switch;

2. The display device according to claim 1, wherein the surge detection circuit comprises: the first diode is electrically connected with the live wire and the detection sub-circuit respectively, the second diode is electrically connected with the zero wire and the detection sub-circuit respectively, and the detection sub-circuit is also electrically connected with the rectifying circuit and the control circuit respectively;

3. The display device according to claim 1, wherein the surge detection circuit comprises: the detection sub-circuit is electrically connected with the rectifying circuit and the control circuit respectively;

4. The display device of claim 2, wherein the detection sub-circuit comprises: the circuit comprises a first resistor, a second resistor and a first capacitor, wherein one end of the first resistor is electrically connected with a first diode and a second diode respectively, the other end of the first resistor is electrically connected with one end of the second resistor, one end of the second resistor is also electrically connected with a control circuit, the other end of the second resistor is connected with a rectifying circuit, and the first capacitor is connected with the second resistor in parallel;

5. The display device according to claim 3, wherein the detection sub-circuit comprises: the rectifier circuit comprises a first resistor, a second resistor and a first capacitor, wherein one end of the first resistor is electrically connected with one end of the rectifier circuit for outputting direct current, the other end of the first resistor is electrically connected with one end of the second resistor, the other end of the second resistor is electrically connected with the other end of the rectifier circuit for outputting direct current, and the first capacitor is connected with the second resistor in parallel;

6. A display device as claimed in claim 4 or 5, characterized in that, if the control circuit comprises: the control sub-circuit is electrically connected with the detection sub-circuit and the power switch respectively, and a second pin of the control chip is electrically connected with the power switch;

the control sub-circuit is configured to receive the first control signal and output a second control signal to the power switch according to the first control signal;

7. The display device according to claim 1, wherein the control sub-circuit comprises: the controllable element is electrically connected with the detection sub-circuit and the first pin of the control chip respectively;

8. The display device according to claim 6, wherein the control sub-circuit comprises controllable elements electrically connected to the detection sub-circuit and the power switch, respectively;

9. A display device as claimed in claim 7 or 8, characterised in that the controllable element is any one of: NPN type triode, PNP type triode, N type metal oxide semiconductor field effect transistor MOS tube, P type metal oxide semiconductor field effect transistor MOS tube.