CN111564144A - Power supply switching control circuit and display device - Google Patents

Abstract

The invention provides a power switching control circuit and a display device. The power switching control circuit includes a voltage input terminal electrically connected to a power supply module, a voltage output terminal electrically connected to a backlight, a control signal input terminal, a voltage regulator switch circuit, a power supply A switch circuit and a current amplifier circuit; the controlled end of the voltage-stabilizing switch circuit is connected to the control signal input end, the first connection end of the voltage-stabilizing switch circuit is connected to the controlled end of the power switch circuit, and the second connection end of the voltage-stabilizing switch circuit Grounding; the controlled end of the current amplifier circuit is connected to the voltage input end, the input end of the current amplifier circuit is connected to the voltage input end, the output end of the current amplifier circuit is connected to the controlled end of the power switch circuit; the input end of the power switch circuit is connected to The voltage input end is connected, and the output end of the power switch circuit is connected with the voltage output end. The technical scheme of the present invention can solve the problem of slow switching of the power switching control device when the backlight is driven by a scanning type.

Description

Power switching control circuit and display device

technical field

The present invention relates to the field of display technology, and in particular, to a power switching control circuit and a display device.

Background technique

Mini LED (also known as millimeter light-emitting diode) has attracted much industry attention as a new technology with promising market prospects. Mini LED backlight has the characteristics of thinness, high image quality and low power consumption. In addition, the Mini LED backlight can be combined with fine area division technology to control the switch and brightness of the corresponding backlight area in real time according to the brightness and darkness of the TV signal. Showy.

Mini LEDs are often powered by high voltage, and the Mini LEDs are driven by a scanning backlight driving method. Using the scanning backlight driving method to drive the Mini LED, it is technically required that the turn-on times of adjacent scanning lines cannot overlap, so as to avoid affecting the display effect of the TV. However, currently, the scanning backlight driving method is used to drive the high-partition backlight, and the power switching control device has problems such as slow switching speed, large circuit loss, and low reliability.

SUMMARY OF THE INVENTION

The present invention provides a power switching control circuit and a display device, aiming at solving the problem of slow switching speed of the power switching control device in the current use of scanning-driven high-division backlights.

In order to achieve the above purpose, the present invention provides a power switching control circuit, the power switching control circuit includes a voltage input terminal electrically connected to a power supply module, a voltage output terminal electrically connected to a backlight, a control signal input terminal, and a voltage regulator switch. circuit, power switch circuit and current amplifier circuit;

The controlled end of the voltage stabilizer switch circuit is connected to the control signal input end, the first connection end of the voltage stabilizer switch circuit is connected to the controlled end of the power switch circuit, and the first connection end of the voltage stabilizer switch circuit is connected to the controlled end of the power switch circuit. The two connection terminals are grounded;

The controlled end of the current amplifying circuit is connected to the voltage input end, the input end of the current amplifying circuit is connected to the voltage input end, and the output end of the current amplifying circuit is controlled by the power switch circuit end connection;

The input end of the power switch circuit is connected to the voltage input end, and the output end of the power switch circuit is connected to the voltage output end;

The voltage regulator switch circuit is used to trigger the power switch circuit to be turned on when receiving a turn-on signal input from the control signal input end;

The voltage-stabilizing switch circuit is further configured to trigger the power switch circuit to disconnect when receiving a shutdown signal input from the control signal input end;

The current amplifying circuit is configured to generate a shut-off driving current to the power switch circuit when the voltage regulator switch circuit triggers the power switch circuit to be disconnected, so as to speed up the disconnection speed of the power switch circuit.

Optionally, the voltage regulator switch circuit includes a first resistor, a second resistor, a first transistor, a diode, a first capacitor and a voltage regulator module;

The first end of the first resistor is connected to the control signal input end, the second end of the first resistor is connected to the first end of the second resistor, the first end of the first capacitor and the The controlled end of the first transistor is connected; the second end of the second resistor, the second end of the first capacitor and the second connection end of the first transistor are grounded;

The first connection end of the first transistor is connected to the cathode of the diode via the voltage regulator module, and the anode of the diode is connected to the controlled end of the power switch circuit.

Optionally, the voltage stabilizing module includes a first zener diode, a second zener diode and a third zener diode;

The anode of the first Zener diode is connected to the first connection end of the first transistor, and the cathode of the first Zener diode is connected to the anode of the second Zener diode; the second Zener diode The negative electrode of the zener diode is connected to the positive electrode of the third zener diode, and the negative electrode of the third zener diode is connected to the controlled end of the power switch circuit.

Optionally, the first transistor is an N-MOS transistor;

The gate of the N-MOS transistor is the controlled terminal of the first transistor, the drain of the N-MOS transistor is the first connection terminal of the first transistor, and the source of the N-MOS transistor is the the second connection terminal of the first transistor.

Optionally, the current amplifying circuit includes a fifth resistor and an NPN triode;

The first end of the fifth resistor is connected to the voltage input end, and the second end of the fifth resistor is connected to the base of the NPN triode and the cathode of the diode;

The collector of the NPN triode is connected to the voltage input end, and the emitter of the NPN triode is connected to the controlled end of the power switch circuit.

Optionally, the power switch circuit includes a third resistor, a fourth resistor and a second transistor;

The first end of the third resistor is the controlled end of the power switch circuit, and the second end of the third resistor is connected to the first end of the fourth resistor and the controlled end of the second transistor ;

The first connection end of the second transistor is the input end of the power switch circuit, and is connected to the second end of the fourth resistor; the second connection end of the second transistor is the input end of the power switch circuit. output.

Optionally, the second transistor is a P-MOS transistor;

The gate of the P-MOS transistor is the controlled terminal of the second transistor, the source of the P-MOS transistor is the first connection terminal of the second transistor, and the drain of the P-MOS transistor is the the second connection terminal of the second transistor.

Optionally, the power switching control circuit further includes a discharge circuit;

The input end of the discharge circuit is connected to the voltage output end, and the output end of the discharge circuit is grounded.

Optionally, the discharge circuit includes a second capacitor, a sixth resistor, a seventh resistor, an eighth resistor and a ninth resistor;

The first end of the second capacitor, the first end of the sixth resistor, the first end of the seventh resistor, the first end of the eighth resistor, and the first end of the ninth resistor are all connected with the voltage output end; the second end of the second capacitor, the second end of the sixth resistor, the second end of the seventh resistor, the second end of the eighth resistor and the The second ends of the ninth resistors are all grounded.

In order to achieve the above object, the present invention also provides a display device comprising the above-mentioned power switching control circuit.

According to the technical scheme of the present invention, when a conduction signal is input at the control signal input terminal, the voltage regulator switch circuit is turned on, and the voltage regulator switch circuit is turned on to trigger the power switch circuit to be turned on quickly, so that the power supply module provides high-voltage power for the backlight. ; When a shutdown signal is input at the control signal input terminal, the voltage stabilizer switch circuit is disconnected, the disconnection of the voltage stabilizer switch circuit triggers the disconnection of the power switch circuit, and the current amplifier circuit is used to speed up the disconnection speed of the power switch circuit. , so that the switching speed of the power switch circuit and the control signal input from the control signal input terminal tend to be synchronized, so as to avoid the intersection of the opening time of the current scanning line and the opening time of the next scanning line, and ensure that the display device can display the picture normally.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained according to the structures shown in these drawings without creative efforts.

1 is a structural block diagram of an embodiment of a power switching control circuit of the present invention;

FIG. 2 is a block diagram of a driving architecture of a Mini LED in an exemplary embodiment;

3 is a schematic diagram of a circuit structure of an embodiment of a power switching control circuit of the present invention;

4 is a structural block diagram of another embodiment of a power switching control circuit according to the present invention;

FIG. 5 is a schematic diagram of the circuit structure of another embodiment of the power switching control circuit of the present invention.

Description of reference numbers:

10 Regulator switch circuit 20 power switch circuit 30 Current amplifier circuit 40 discharge circuit 101 Voltage regulator module Q1 first transistor Q2 second transistor Q3 NPN tertiary tube R1～R9 The first resistance to the ninth resistance T1 first Zener diode T2 Second Zener Diode T3 Third Zener Diode C1 first capacitor C2 second capacitor D2 diode GND land Vin Voltage input Vout Voltage output 100 Power switching control device 200 Mini LED Module 300 Constant current control system

The realization, functional characteristics and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that if there are directional indications (such as up, down, left, right, front, back, etc.) involved in the embodiments of the present invention, the directional indications are only used to explain a certain posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly.

In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for the purpose of description, and should not be construed as indicating or implying Its relative importance or implicitly indicates the number of technical features indicated. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In addition, the technical solutions between the various embodiments can be combined with each other, but must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of such technical solutions does not exist. , is not within the scope of protection required by the present invention.

FIG. 1 is a structural block diagram of an embodiment of a power switching control circuit of the present invention.

Referring to FIG. 1 , the power switching control circuit includes a voltage input terminal Vin electrically connected to a power supply module, a voltage output terminal Vout electrically connected to a backlight on a scan line, a control signal input terminal EN, a voltage regulator switch circuit 10, a power supply a switch circuit 20 and a current amplifying circuit 30;

The controlled terminal of the voltage-stabilizing switch circuit 10 is connected to the control signal input terminal EN, the first connection terminal of the voltage-stabilizing switch circuit 10 is connected to the controlled terminal of the power switch circuit 20, and the second terminal of the voltage-stabilizing switch circuit 10 is connected to the controlled terminal of the power switch circuit 20. The connection terminal is grounded; the controlled terminal of the current amplifier circuit 30 is connected to the voltage input terminal Vin, the input terminal of the current amplifier circuit 30 is connected to the voltage input terminal Vin, and the output terminal of the current amplifier circuit 30 is connected to the power switch circuit 20 is connected to the controlled end. The input terminal of the power switch circuit 20 is connected to the voltage input terminal Vin, and the output terminal of the power switch circuit 20 is connected to the voltage output terminal Vout.

The voltage-stabilizing switch circuit 10 has two states of on and off. When the voltage-stabilizing switch circuit 10 is turned on, the power switch circuit 20 can be triggered to be turned on, and the potential clamp of the controlled end of the power switch circuit 20 can be clamped. at a fixed voltage. When the voltage regulator switch circuit 10 is disconnected, the power switch circuit 20 can be triggered to be disconnected accordingly.

The current amplifying circuit 30 can be implemented by using a circuit composed of triode elements or other circuits having a current amplifying effect. The current amplifying circuit 30 is used to provide a sufficiently large turn-off drive current for the controlled end of the power switch circuit 20 when the power switch circuit 20 is triggered to disconnect, so as to speed up the disconnection speed of the power switch circuit 20 .

The power switch circuit 20 has two states of on and off, and can be realized by a circuit composed of MOS transistors.

The technical solution of this embodiment can be applied to a display device using Mini LED as a backlight source, for example, a TV using Mini LED as a backlight source. At present, display devices that use Mini LEDs as backlight sources often use high voltage to power Mini LEDs, and drive high-division Mini LEDs through scanning. For example, a Mini LED driving architecture shown in FIG. 2 includes a power switching control device 100 , a Mini LED module 200 and a constant current control system 300 . It is assumed that the driving structure adopts a 5-scan scanning method to drive the high-division Mini LED, and the scanning frequency is F (1KHz to 10KHz), and the switching period of the power switching control device 100 is T. Then, the turn-on time of each scanning line is about is T/5 (a very short dead time is also included in the middle of the line and the line), then the scanning line 1, scanning line 2, scanning line 3, scanning line 4 and scanning line 5 are turned on alternately with a duty cycle of about 20%. . Therefore, in order to make the display device display normally, the turn-on time of the previous scan line cannot intersect with the turn-on time of the next scan line. Therefore, the switching speed of each switch tube in the power switching control device 100 needs to be fast enough.

In order to solve the above problems, the present invention provides a power switching control circuit, which is applied to a power switching control device. The power switching control device includes a plurality of power switching control circuits with the same structure, and each power switching control circuit is used to control a switch of a scan line.

Specifically, when the control signal input terminal EN inputs a turn-on signal to the voltage-stabilizing switch circuit 10, the voltage-stabilizing switch circuit 10 can be triggered to be turned on. The turn-on signal can be a high level or a low level, which can be set according to the type of transistors in the voltage regulator switch circuit 10. The control signal can be sent by the controller of the system, and the controller in the system controls the entire Mini The work of the LED backlight system is responsible for the communication with the main SOC (system on chip) and the backlight control chip and the power supply control of the scan line. When the voltage regulator switch circuit 10 is turned on, the power switch circuit 20 can be triggered to be turned on, and the controlled end of the power switch circuit 20 can be clamped at a certain fixed voltage. If the resistance value of the driving resistor of the MOS transistor in the power switch circuit 20 is set to be small enough, such as 2 ohms, 2.2 ohms, etc., then when the voltage regulator switch circuit 10 is turned on, the MOS transistor in the power switch circuit 20 is turned on. The driving current is large enough. Therefore, when the voltage regulator switch circuit 10 is turned on, the power switch circuit 20 can be triggered to turn on quickly, so that the voltage input terminal Vin and the voltage output terminal Out are quickly electrically connected, and the power supply module outputs high-voltage power, such as The 46V high-voltage power supplies power to the backlight of the scanning line where the power switching control circuit is located.

When the control signal input terminal EN inputs a shutdown signal to the voltage stabilization switch circuit 10, the voltage stabilization switch circuit 10 can be controlled to be disconnected, and the power supply switch circuit 20 is triggered to be disconnected by controlling the voltage stabilization switch circuit 10 to be disconnected, and the current amplification is triggered The circuit is on. During the disconnection process of the power switch circuit 20, the current amplifier circuit 30 provides a sufficiently large turn-off drive current for the power switch circuit 20 to speed up the disconnection speed of the power switch circuit 20, and the power supply module stops scanning for the location of the power switch control circuit. The row of backlights are powered. That is to say, the technical solution of this embodiment combines the voltage-stabilizing switching circuit 10 with the current amplifying circuit 20 to speed up the switching speed of the power switching circuit 20, so that the switching speed of the power switching circuit 20 and the control signal input terminal EN input The control signals tend to be synchronized, so as to avoid the intersection of the opening time of the current scan line and the next scan line, and to ensure that the display device can display the picture normally.

According to the technical solution of the present invention, when the control signal input terminal EN inputs a conduction signal, the voltage regulator switch circuit 10 is turned on, and the voltage regulator switch circuit 10 is turned on to trigger the power switch circuit 20 to be quickly turned on, so that the power supply module is the The power supply switching control circuit is used to supply power to the backlight of the scanning line; when the control signal input terminal EN inputs a shutdown signal, the voltage stabilization switch circuit 10 is disconnected, and the disconnection of the voltage stabilization switch circuit 10 triggers the disconnection of the power switch circuit 20 At the same time, the current amplifying circuit 30 is used to speed up the disconnection speed of the power switch circuit 20, so that the switching speed of the power switch circuit 20 and the control signal input by the control signal input terminal EN tend to be synchronized, so as to avoid the current scanning line and the next scanning line. The turn-on time is crossed to ensure that the display device can display the picture normally.

Optionally, referring to FIG. 3 , in an embodiment, the voltage stabilization switch circuit 10 includes a first resistor R1, a second resistor R2, a first transistor Q1, a diode D1, a first capacitor C1, and a voltage stabilization module 101;

The first end of the first resistor R1 is connected to the control signal input end EN, the second end of the first resistor R1 is connected to the first end of the second resistor R2, the first end of the first capacitor C1 and the first transistor The controlled end of Q1 is connected; the second end of the second resistor R2, the second end of the first capacitor C1 and the second connection end of the first transistor Q1 are grounded; the first connection end of the first transistor Q1 The voltage module 101 is connected to the cathode of the diode D1 , and the anode of the diode D1 is connected to the controlled end of the power switch circuit 20 .

In this embodiment, the first transistor Q1 may be a P-MOS transistor or an N-MOS transistor. For convenience of description, the working principle of the voltage regulator switch circuit 10 is described below by taking the first transistor Q1 as an N-MOS transistor as an example. The gate of the N-MOS transistor is set as the controlled terminal of the first transistor Q1, the drain of the N-MOS transistor is the first connection terminal of the first transistor Q1, and the source of the N-MOS transistor is the first connection terminal of the first transistor Q1. Two connection terminals. It should be noted that since the MOS tube is a voltage control element, its working state is mainly determined by the gate-source voltage Vgs, that is to say, when Vgs is less than the turn-on voltage of the MOS tube, the MOS tube works in an off state, and when Vgs is greater than When the turn-on voltage of the MOS tube is turned on, the MOS tube works in a conducting state. However, there is a parasitic capacitance between the gate and the drain of the MOS tube, and the driving of the MOS tube actually charges and discharges the capacitance. Therefore, when selecting an N-MOS tube, the selected Vds voltage is high enough, the gate and source of the MOS tube, and the junction capacitance between the gate and the drain of the MOS tube is small enough to ensure that the switching speed of the MOS tube is comparable to that of the MOS tube. The control signals tend to be synchronized.

Specifically, when the control signal input terminal EN inputs a high-level turn-on signal, the N-MOS transistor Q1 is turned on. At this time, the voltage regulator module 101 clamps the cathode of the diode D1 at a certain fixed voltage, for example, Clamped at 42V, and due to the voltage drop of the diode D1, the anode voltage of the diode D1 is greater than its cathode voltage, for example, the anode voltage of the diode D1 is clamped at about 42.7V. If the resistance value of the driving resistor on the gate of the MOS transistor in the power switch circuit 20 is set to be small enough, such as 2 ohms, 2.2 ohms, etc., then when the N-MOS transistor Q1 is turned on, the power switch circuit 20 The turn-on driving current of the MOS transistor is large enough. Therefore, when the N-MOS transistor Q1 is turned on, the power switch circuit 20 can be triggered to turn on quickly, the voltage input terminal Vin and the voltage output terminal Out are quickly electrically connected, and the power supply module outputs High-voltage electric energy, such as 46V high-voltage electric energy, supplies power to the backlight of the scanning line where the power switching control circuit is located. In this way, the conduction speed of the power switch circuit 20 and the conduction signal input from the control signal input terminal EN can be synchronized. At the same time, the gate of the MOS transistor in the power switch circuit 20 is discharged through the drive resistor of the power switch circuit 20 , the diode D1 , the voltage regulator module 101 and the N-MOS transistor Q1 . Since the power consumption of the voltage regulator module 101 is relatively small, the circuit loss can be reduced and the circuit temperature can be prevented from being too high. The voltage stabilization module 101 determines the voltage fluctuation range of the MOS transistor in the power switch circuit 20. For example, the voltage of the controlled terminal of the MOS transistor in the power switch circuit 20 is controlled to be between 42V and 46V, which further speeds up the power switch circuit. The conduction speed of the MOS tube in 20 is prevented, and at the same time, the MOS tube in the power switch circuit 20 is prevented from being burned out.

Optionally, in an embodiment, the voltage regulator module 101 includes a first voltage regulator diode T1, a second voltage regulator diode T2 and a third voltage regulator diode T3; the anode of the first voltage regulator diode T1 is connected to the first voltage regulator diode T1. The first connection end of the transistor Q1 is connected, the cathode of the first Zener diode T1 is connected to the anode of the second Zener diode T2; the cathode of the second Zener diode T2 is connected to the anode of the third Zener diode T3 , the negative electrode of the third Zener diode T3 is connected to the controlled end of the power switch circuit 20 . Optionally, the first Zener diode T1, the second Zener diode T2 and the third Zener diode T3 can be selected as Zener diodes with the same specifications, for example, a Zener diode with a voltage regulator value of 14V can also be selected according to The setting of the withstand voltage value of the MOS transistor in the power switch circuit 20 is not limited here.

Optionally, referring to FIG. 3 , in one embodiment, the current amplifying circuit 30 includes a fifth resistor R5 and an NPN triode Q3; the first end of the fifth resistor R5 is connected to the voltage input end Vin, and the first end of the fifth resistor R5 The second end of the five resistors R5 is connected to the base of the NPN triode Q3 and the cathode of the diode D1 in the voltage regulator switch circuit 10; the collector of the NPN triode Q3 is connected to the voltage input terminal Vin, and the NPN The emitter of the triode Q3 is connected to the controlled end of the power switch circuit 20 .

The specific working principle is as follows: when the voltage regulator switch circuit 10 is turned on, the NPN transistor Q3 is in an off state. When the voltage regulator switch circuit 10 is turned off, the NPN transistor Q3 is turned on under the driving action of the fifth resistor R5. Because the NPN triode Q3 has a current amplifying effect, when the voltage regulator switch circuit 10 is turned off, the NPN triode Q3 can provide a sufficiently large turn-off drive current for the gate of the MOS transistor in the power switch circuit 20 For example, if the base current of the NPN transistor Q3 is set as Ib, then the turn-off driving current of the gate of the MOS transistor in the power switch circuit 20 can reach β*Ib, so that the voltage regulator switch circuit 10 is disconnected When the speed of the gate voltage of the MOS transistor in the power switch circuit 20 becomes high, for example, it is equal to the voltage input by the voltage input terminal Vin, so that the MOS transistor in the power switch circuit 20 is quickly disconnected. In this way, the power switch can be realized. The turn-off speed of the circuit 20 tends to be synchronized with the turn-off signal input at the control signal input terminal EN. Among them, the diode D1 in the regulated switching circuit 10 is used to protect the base of the NPN triode Q3, so as to avoid damage to the NPN triode due to the voltage difference between the emitter voltage and the base voltage of the NPN triode Q3 exceeding the limit value. Tube Q3. The fifth resistor R5 is a current-limiting resistor. When the voltage-stabilizing switch circuit 10 is turned on, the power consumption of the voltage-stabilizing module 101 in the voltage-stabilizing switch circuit 10 can be reduced due to the current-limiting effect of the fifth resistor R5. Effectively reduce circuit loss and avoid excessive circuit temperature.

Optionally, referring to FIG. 3 , in one embodiment, the power switch circuit 20 includes a third resistor R3 , a fourth resistor R4 and a second transistor Q2 ; the first end of the third resistor R3 is the power switch circuit 20 , the second end of the third resistor R3 is connected to the first end of the fourth resistor R4 and the controlled end of the second transistor Q2; the first connection end of the second transistor Q2 is the power switch The input end of the circuit 20 is connected to the second end of the fourth resistor R4 ; the second connection end of the second transistor Q2 is the output end of the power switch circuit 20 .

Wherein, the second transistor Q2 can be selected as a P-MOS transistor, the gate of the P-MOS transistor is the controlled terminal of the second transistor Q2, the source of the P-MOS transistor is the first connection terminal of the second transistor Q2, and P -The drain of the MOS transistor is the second connection terminal of the second transistor Q2. It should be noted that since the MOS tube is a voltage control element, its working state is mainly determined by the gate-source voltage Vgs. That is to say, when Vgs is less than the turn-on voltage, the MOS tube works in an off state, and when Vgs is greater than the turn-on voltage. , the MOS tube works in a conducting state. However, there is a parasitic capacitance between the gate and the drain of the MOS tube, and the driving of the MOS tube actually charges and discharges the capacitance. Therefore, when selecting the P-MOS transistor Q2, the selected Vds voltage is high enough, the junction capacitance between the gate and the source of the MOS transistor, and the junction capacitance between the gate and the drain of the MOS transistor is small enough to further ensure the P-MOS transistor. The switching speed tends to be synchronized with the control signal.

Specifically, when the voltage regulator switch circuit 10 is turned on, the gate of the P-MOS transistor Q2 is clamped at a certain fixed voltage, for example, at about 42.7V, and at this time, the P-MOS transistor Q2 is turned on . If the resistance value of the third resistor R3 is set to be small enough, for example, 2 ohms and 2.2 ohms, then the turn-on driving current of the gate of the P-MOS transistor Q2 can be made large enough, and the P-MOS transistor Q2 can achieve fast on. That is to say, the third resistor R3 of the gate of the P-MOS transistor Q2 is set to a resistor with a small resistance value, so that when the voltage regulator switch circuit 10 is turned on, the turn-on driving current of the gate of the P-MOS transistor Q2 is sufficient. Therefore, the conduction of the P-MOS transistor Q2 and the conduction signal input by the control signal input terminal EN tend to be synchronized. The fast turn-on of the P-MOS transistor Q2 can make the voltage input terminal Vin and the voltage output terminal Out quickly electrically connected, and the power supply module outputs high-voltage power, such as 46V high-voltage power to supply power for the backlight of the scan line where the power switching control circuit is located.

When the voltage regulator switch circuit 10 is turned off, the current amplifying circuit 30 is turned on under the action of its internal driving resistor. Since the current amplifying circuit 30 has a current amplifying function, when the voltage-stabilizing switch circuit 10 is turned off, the current amplifying circuit 30 can provide a sufficiently large turn-off drive current for the gate of the P-MOS transistor Q2, so that the P-MOS transistor The gate voltage of Q2 rapidly becomes high, for example, equal to the voltage input by the voltage input terminal Vin, thereby triggering the rapid disconnection of the P-MOS transistor Q2, thereby enabling the turn-off speed of the P-MOS transistor Q2 and the turn-off of the control signal input terminal input. The signals tend to be in sync.

Optionally, referring to FIG. 4 , in an embodiment, the power switching control circuit further includes a discharge circuit 40 ; the input terminal of the discharge circuit 40 is connected to the voltage output terminal Vout, and the output terminal of the discharge circuit 40 is grounded.

The discharge circuit 40 is used to rapidly discharge the residual charge of the back-end circuit when the power switch circuit 20 is turned off, so that the voltage of the voltage output terminal Vout rapidly becomes lower, and further avoids the occurrence of crossover of the on-time of adjacent scan lines. , thereby effectively improving the display stability and reliability of the display device.

Optionally, referring to FIG. 5 , in one embodiment, the discharge circuit 40 includes a second capacitor C2, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9; The first end, the first end of the sixth resistor R6, the first end of the seventh resistor R7, the first end of the eighth resistor R8 and the first end of the ninth resistor R9 are all connected to the voltage output end Vout; The second end of the second capacitor C2, the second end of the sixth resistor R6, the second end of the seventh resistor R7, the second end of the eighth resistor R8 and the second end of the ninth resistor R9 are all grounded.

In this embodiment, when the power switch circuit 20 is turned off, the residual charge in the back-end circuit is rapidly discharged through the sixth resistor R6, the seventh resistor R7, the eighth resistor R8 and the ninth resistor R9, so that the voltage output terminal The voltage of Vout decreases rapidly, which further avoids the overlapping of the turn-on times of adjacent scanning lines, thereby effectively improving the display stability and reliability of the display device.

In order to better illustrate the inventive concept of the present invention, the overall inventive concept of the present invention is described below with reference to FIG. 5 .

Referring to FIG. 5 , when the control signal input from the control signal input terminal EN is at a high level, the N-MOS transistor Q1 is turned on. The first Zener diode T1, the second Zener diode T2 and the third Zener diode T3 clamp the cathode of the diode D1 at a certain fixed voltage, for example, at 42V. Since the diode D1 has a certain voltage drop effect, so , the anode voltage of the diode D1 is greater than its cathode voltage. For example, when the cathode voltage of the diode D1 is 42V, the anode voltage of the diode D1 is about 42.7V. At this time, due to the current limiting effect of the fifth resistor R5, for example, the current limiting effect of the fifth resistor R5 of 2.2KΩ, the power generated by the first Zener diode T1, the second Zener diode T2 and the third Zener diode T3 The consumption is small, which can effectively reduce the circuit loss and avoid the circuit temperature being too high. At the same time, since the resistance value of the third resistor R3 of the P-MOS transistor Q2 is small, such as 2.2Ω, the turn-on driving current of the P-MOS transistor Q2 is large enough, so the P-MOS transistor Q2 can be turned on quickly, Its conduction speed tends to be synchronized with the high level control signal input by the control signal input terminal EN. At this time, the power supply module outputs high-voltage power, for example, 46V high-voltage power to supply power to the backlight of the scan line where the power switching control circuit is located.

When the control signal input from the control signal input terminal EN is at a low level, the N-MOS transistor Q1 is turned off, and the first Zener diode T1 , the second Zener diode T2 and the third Zener diode T3 are in an open state. The NPN transistor Q3 is turned on under the driving action of the fifth resistor R5. Because the NPN transistor Q3 has a current amplification function, the amplification factor is often several hundred times, which can make the turn-off driving current of the P-MOS transistor Q2 large enough, and finally trigger the P-MOS transistor Q2 to be quickly disconnected, so that the P-MOS transistor Q2 is turned off quickly. The disconnection speed tends to be synchronized with the low level control signal input at the control signal input terminal. At the same time, the residual charge in the back-end circuit is rapidly discharged through the sixth resistor R6, the seventh resistor R7, the eighth resistor R8 and the ninth resistor R9, so that the voltage of the voltage output terminal Vout decreases rapidly and further avoids phase The opening times of adjacent scanning lines are crossed, thereby effectively improving the display stability and reliability of the display device. That is to say, the technical solution of the present invention can realize that the control signal input end and the switch of the P-MOS transistor tend to be synchronized, thereby avoiding the intersection of the opening time of the current scanning line and the opening time of the next scanning line, and ensuring that the display device can The screen is displayed normally, and the display effect is more stable.

Among them, the diode D1 is used to protect the NPN triode Q3, so as to avoid damage to the NPN triode Q3 because the voltage difference between the emitter voltage and the base voltage of the NPN triode Q3 exceeds the limit value. The first Zener diode T1, the second Zener diode T2 and the third Zener diode T3 are used to clamp the gate voltage of the P-MOS transistor Q2 within a certain voltage range, for example, between 42V and 46V. During the time, it is beneficial to reduce the voltage change of the P-MOS transistor Q2, speed up the conduction speed of the P-MOS transistor Q2, and prevent the P-MOS transistor Q2 from being damaged. At the same time, the first Zener diode T1, the second Zener diode T2 and the third Zener diode T3 are also used for switching control of switching from high voltage to low voltage.

To sum up, the technical solution of the present invention combines the current amplifying circuit 30 composed of triodes with the voltage-stabilizing switch circuit 20, which not only solves the problem of large loss when the power switch circuit 20 is turned on, but also solves the problem of the power switch circuit 20 The problem of small turn-off driving current when disconnected can effectively ensure that the control signal and the switch of the power switch circuit 20 tend to be synchronized, so as to ensure that the display device can display images normally.

The present invention also provides a display device, the display device includes the above-mentioned power switching control circuit, and the detailed structure of the power switching control circuit can refer to the above-mentioned embodiments, which will not be repeated here; The above-mentioned power switching control circuit is used in the display device of the present invention. Therefore, the embodiments of the display device of the present invention include all the technical solutions of all the above-mentioned embodiments of the power switching control circuit, and the technical effects achieved are also the same. Repeat.

The above descriptions are only optional embodiments of the present invention, and are not intended to limit the scope of the present invention. Under the inventive concept of the present invention, any equivalent structural transformations made by using the contents of the description and drawings of the present invention, or direct/indirect Applications in other related technical fields are included in the scope of patent protection of the present invention.

Claims (10)

1. A power supply switching control circuit is characterized by comprising a voltage input end electrically connected with a power supply module, a voltage output end electrically connected with a backlight lamp, a control signal input end, a voltage stabilizing switch circuit, a power supply switch circuit and a current amplifying circuit;

the controlled end of the voltage stabilizing switch circuit is connected with the control signal input end, the first connecting end of the voltage stabilizing switch circuit is connected with the controlled end of the power switch circuit, and the second connecting end of the voltage stabilizing switch circuit is grounded;

the controlled end of the current amplification circuit is connected with the voltage input end, the input end of the current amplification circuit is connected with the voltage input end, and the output end of the current amplification circuit is connected with the controlled end of the power switch circuit;

the input end of the power switch circuit is connected with the voltage input end, and the output end of the power switch circuit is connected with the voltage output end;

the voltage stabilizing switch circuit is used for triggering the power switch circuit to be conducted when receiving a conducting signal input by the control signal input end;

the voltage stabilizing switch circuit is also used for triggering the power switch circuit to be switched off when receiving a turn-off signal input by the control signal input end;

the current amplifying circuit is used for generating a turn-off driving current to the power switch circuit when the voltage stabilizing switch circuit triggers the power switch circuit to be turned off so as to accelerate the turn-off speed of the power switch circuit.

2. The power switching control circuit of claim 1, wherein the regulated switching circuit comprises a first resistor, a second resistor, a first transistor, a diode, a first capacitor, and a regulation module;

a first end of the first resistor is connected with the control signal input end, and a second end of the first resistor is connected with a first end of the second resistor, a first end of the first capacitor and a controlled end of the first transistor; a second end of the second resistor, a second end of the first capacitor and a second connecting end of the first transistor are grounded;

the first connection end of the first transistor is connected with the cathode of the diode through the voltage stabilizing module, and the anode of the diode is connected with the controlled end of the power switch circuit.

3. The power switching control circuit of claim 2, wherein the voltage regulator module comprises a first voltage regulator diode, a second voltage regulator diode, and a third voltage regulator diode;

the anode of the first voltage stabilizing diode is connected with the first connecting end of the first transistor, and the cathode of the first voltage stabilizing diode is connected with the anode of the second voltage stabilizing diode; and the cathode of the second voltage-stabilizing diode is connected with the anode of the third voltage-stabilizing diode, and the cathode of the third voltage-stabilizing diode is connected with the controlled end of the power switch circuit.

4. The power switching control circuit of claim 3 wherein said first transistor is an N-MOS transistor;

the grid electrode of the N-MOS tube is the controlled end of the first transistor, the drain electrode of the N-MOS tube is the first connecting end of the first transistor, and the source electrode of the N-MOS tube is the second connecting end of the first transistor.

5. The power switching control circuit of claim 2, wherein the current amplification circuit comprises a fifth resistor and an NPN triode;

a first end of the fifth resistor is connected with the voltage input end, and a second end of the fifth resistor is connected with a base electrode of the NPN triode and a negative electrode of the diode;

and the collector of the NPN triode is connected with the voltage input end, and the emitter of the NPN triode is connected with the controlled end of the power switching circuit.

6. The power switching control circuit of claim 1, wherein the power switching circuit comprises a third resistor, a fourth resistor, and a second transistor;

the first end of the third resistor is a controlled end of the power switch circuit, and the second end of the third resistor is connected with the first end of the fourth resistor and the controlled end of the second transistor;

the first connecting end of the second transistor is the input end of the power switch circuit and is connected with the second end of the fourth resistor; and the second connecting end of the second transistor is the output end of the power switch circuit.

7. The power switching control circuit of claim 6, wherein the second transistor is a P-MOS transistor;

the grid electrode of the P-MOS transistor is the controlled end of the second transistor, the source electrode of the P-MOS transistor is the first connecting end of the second transistor, and the drain electrode of the P-MOS transistor is the second connecting end of the second transistor.

8. The power supply switching control circuit according to any one of claims 1 to 7, wherein the power supply switching control circuit further comprises a discharge circuit;

the input end of the discharge circuit is connected with the voltage output end, and the output end of the discharge circuit is grounded.

9. The power switching control circuit of claim 8, wherein the discharge circuit comprises a second capacitor, a sixth resistor, a seventh resistor, an eighth resistor, and a ninth resistor;

the first end of the second capacitor, the first end of the sixth resistor, the first end of the seventh resistor, the first end of the eighth resistor and the first end of the ninth resistor are all connected with the voltage output end; the second end of the second capacitor, the second end of the sixth resistor, the second end of the seventh resistor, the second end of the eighth resistor and the second end of the ninth resistor are all grounded.

10. A display device characterized in that the display device comprises the power supply switching control circuit according to any one of claims 1 to 9.

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