CN211087888U - Backlight driving circuit and electronic equipment - Google Patents
Backlight driving circuit and electronic equipment Download PDFInfo
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- CN211087888U CN211087888U CN201922095825.7U CN201922095825U CN211087888U CN 211087888 U CN211087888 U CN 211087888U CN 201922095825 U CN201922095825 U CN 201922095825U CN 211087888 U CN211087888 U CN 211087888U
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Abstract
The utility model discloses a drive circuit and electronic equipment are shaded, drive circuit is shaded includes power module, the module that steps up, compares module and control module. The comparison module is used for collecting the voltage of the output end of the boosting module, and when the collected voltage of the output end of the boosting module is increased to a preset value, the comparison module sends a first signal to the control module. The control module sends a second signal to the power module according to the first signal so as to improve the power supply voltage of the output end of the power module, further reduce the voltage difference between the power supply voltage of the output end of the power module and the driving voltage required by the backlight module (namely, the voltage of the output end of the boosting module), further shorten the time required by the process of boosting the power supply voltage to the driving voltage of the backlight module, improve the working efficiency of the boosting module, and avoid the situation that the boosting module generates heat seriously and even cannot work.
Description
Technical Field
The utility model relates to a drive technique in a poor light especially relates to a drive circuit and electronic equipment in a poor light.
Background
With the continuous popularization of smart televisions (e.g., liquid crystal flat panel televisions), the size of the liquid crystal flat panel television is larger and larger, e.g., the size of a common liquid crystal flat panel television is 32 inches, 43 inches, 49 inches, and the like, so that the power of a television mainboard is larger and larger, and meanwhile, with the increasing functions of intelligent application software, the power supply part of the liquid crystal flat panel television has higher requirements.
In the conventional backlight driving technology, a voltage boosting circuit is usually adopted to boost the voltage of the power supply input so as to supply power to the backlight L ED.
SUMMERY OF THE UTILITY MODEL
The utility model provides a drive circuit and electronic equipment are shaded can improve the work efficiency of the module that steps up, avoids the module that steps up to generate heat seriously, the condition that can not work even.
In a first aspect, an embodiment of the present invention provides a backlight driving circuit, which includes: the device comprises a power supply module, a boosting module, a comparison module and a control module;
the output end of the power supply module is connected with the input end of the boosting module, and the output end of the boosting module is used for being connected with the backlight module;
the input end of the comparison module is connected with the output end of the boosting module, and the output end of the comparison module is connected with the input end of the control module; the comparison module is used for acquiring the voltage of the output end of the boosting module and sending a first signal to the control module based on the voltage of the output end of the boosting module;
the output end of the control module is connected with the power supply module, and the control module is used for sending a second signal to the power supply module according to the first signal so as to improve the power supply voltage of the output end of the power supply module.
Optionally, the comparing module includes a comparing unit and a first switch unit;
the first input end of the comparison unit is connected with the output end of the boosting module, and the second input end of the comparison unit is used for accessing a reference voltage; the comparison unit is used for sending a conducting signal to the first switch unit when the voltage of the first input end of the comparison unit is greater than the reference voltage;
the output end of the comparison unit is connected with the control end of the first switch unit, the first end of the first switch unit is grounded, and the second end of the first switch unit is connected with the input end of the control module; the first switch unit is used for sending the first signal to the control module according to the conducting signal.
Optionally, the comparison unit includes a voltage comparator, a first resistor, a second resistor, and a first capacitor;
the first end of the first resistor is connected with the output end of the boosting module, and the second end of the first resistor is connected with the positive input end of the voltage comparator;
the first end of the second resistor is connected with the positive input end of the voltage comparator, and the second end of the second resistor is grounded;
the negative input end of the voltage comparator is used for inputting the reference voltage;
the first end of the first capacitor is connected with the negative input end of the voltage comparator, and the second end of the first capacitor is grounded.
Optionally, the first switching unit includes a first switching transistor, a third resistor, a fourth resistor, and a fifth resistor;
the first end of the third resistor is connected with the output end of the comparison unit, and the second end of the third resistor is connected with the control end of the first switch transistor;
a first end of the fourth resistor is connected with the control end of the first switching transistor, and a second end of the fourth resistor is grounded;
a first end of the first switch transistor is grounded, and a second end of the first switch transistor is connected with a first end of the fifth resistor;
and the second end of the fifth resistor is connected with the input end of the control module.
Optionally, the control module includes an acquisition unit, a first control chip, and a second switch unit;
the input end of the acquisition unit is connected with the output end of the comparison module, and the output end of the acquisition unit is connected with the input end of the first control chip; the acquisition unit is used for sending a feedback signal to the first control chip according to the first signal;
the output end of the first control chip is connected with the control end of the second switch unit, and the output end of the second switch unit is connected with the power supply module; the first control chip is used for controlling the second switch unit to send the second signal to the power module according to the feedback signal.
Optionally, the acquisition unit includes an optocoupler, a voltage reference chip, a sixth resistor, and a seventh resistor;
the first end of the optical coupler is used for inputting an optical coupler power supply, the second end of the optical coupler is connected with the first end of the voltage reference chip, and the second end of the voltage reference chip is grounded;
the third end of the optical coupler is grounded, and the fourth end of the optical coupler is connected with the input end of the first control chip;
the third end of the voltage reference chip is connected with the output end of the comparison module;
the first end of the seventh resistor is connected with the output end of the power supply module, and the second end of the seventh resistor is connected with the output end of the comparison module;
and the first end of the sixth resistor is connected with the third end of the voltage reference chip, and the second end of the sixth resistor is grounded.
Optionally, the second switching unit includes a second switching transistor, an eighth resistor, a ninth resistor, and a second capacitor;
a first end of the eighth resistor is connected with the output end of the first control chip, and a second end of the eighth resistor is connected with the control end of the second switching transistor;
a first end of the second switching transistor is connected with the power supply module, and a second end of the second switching transistor is connected with a first end of the ninth resistor;
a second end of the ninth resistor is grounded;
the first end of the second capacitor is connected with the first end of the second switch transistor, and the second end of the second capacitor is connected with the second end of the second switch transistor.
Optionally, the boost module includes a boost unit and a second control chip;
the input end of the boosting unit is connected with the output end of the power supply module, and the output end of the boosting unit is used for being connected with the backlight module;
and the output end of the second control chip is connected with the control end of the boosting unit.
Optionally, the boosting unit includes a diode, a third switching transistor, an inductor, and an electrolytic capacitor;
the first end of the inductor is connected with the output end of the power supply module, and the second end of the inductor is connected with the anode of the diode;
the cathode of the diode is connected with the backlight module;
the first end of the electrolytic capacitor is connected with the cathode of the diode, and the second end of the electrolytic capacitor is grounded;
the first end of the third switching transistor is connected with the second end of the inductor, the second end of the third switching transistor is used for accessing a reference level, and the control end of the third switching transistor is connected with the output end of the second control chip.
In a second aspect, an embodiment of the present invention provides an electronic device, including the present invention provides a backlight driving circuit.
The embodiment of the utility model provides a drive circuit in a poor light includes power module, the module that steps up, compares module and control module. The comparison module is used for collecting the voltage of the output end of the boosting module, and when the collected voltage of the output end of the boosting module is increased to a preset value, the comparison module sends a first signal to the control module. The control module sends a second signal to the power module according to the first signal so as to improve the power supply voltage of the output end of the power module, further reduce the voltage difference between the power supply voltage of the output end of the power module and the driving voltage required by the backlight module (namely, the voltage of the output end of the boosting module), further shorten the time required by the process of boosting the power supply voltage to the driving voltage of the backlight module, improve the working efficiency of the boosting module, and avoid the situation that the boosting module generates heat seriously and even cannot work.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Fig. 1 is a block diagram of a backlight driving circuit according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a backlight driving circuit according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another backlight driving circuit according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of another backlight driving circuit according to an embodiment of the present invention;
fig. 5 is a circuit diagram of a backlight driving circuit according to an embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and technical effects achieved by the present invention more clear, the embodiments of the present invention will be described in further detail with reference to the accompanying drawings, and obviously, the described embodiments are only some embodiments, not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present invention.
In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, detachably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
However, the power supply can not be replaced generally, which causes the difference between the voltage output by the power supply and the voltage required by the backlight L ED to be larger, and further the process of boosting the voltage output by the power supply to the voltage required by the backlight L ED requires a longer time, which causes the situation that the working efficiency of the booster circuit is low, and the working efficiency of the booster circuit further causes the booster circuit to generate heat seriously, or even can not work.
To the above problem, the embodiment of the utility model provides a drive circuit is shaded, this embodiment can be adapted to the low condition of boost circuit work efficiency in the drive of being shaded of liquid crystal display device, and this drive circuit is shaded can set up in electronic equipment, and wherein, electronic equipment can be liquid crystal display devices such as intelligent TV. Fig. 1 is a block diagram of a backlight driving circuit according to an embodiment of the present invention, as shown in fig. 1, the backlight driving circuit includes: a power module 110, a boost module 120, a comparison module 130, and a control module 140.
The output end of the power module 110 is connected to the input end of the voltage boosting module 120, and the output end of the voltage boosting module 120 is used for connecting the backlight module 150, wherein the backlight module 150 may include a plurality of backlight L ED light bars, and each backlight L ED light bar may include a plurality of L ED light beads.
The input end of the comparison module 120 is connected with the output end of the boosting module 120, and the output end of the comparison module 130 is connected with the input end of the control module 140; the comparison module 130 is configured to collect a voltage at an output end of the voltage boosting module 120, and send a first signal to the control module 140 based on the voltage at the output end of the voltage boosting module 120.
The output terminal of the control module 140 is connected to the power module 110, and the control module 140 is configured to send a second signal to the power module 110 according to the first signal to increase the power voltage VB L at the output terminal of the power module 110.
Specifically, the power module 110 outputs the power voltage VB L to the voltage boost module 120, and the voltage boost module 120 boosts the power voltage VB L, so that the boosted voltage meets the driving voltage of the backlight module 150. when the liquid crystal device becomes larger, that is, the number of L ED beads of the backlight module 150 increases, the driving voltage required by the backlight module 150 also increases correspondingly, and the voltage output by the voltage boost module 120 increases correspondingly, the comparison module 130 is used for collecting the voltage at the output end of the voltage boost module 120, and when the collected voltage at the output end of the voltage boost module 120 increases to a preset value, the comparison module 130 sends a first signal to the control module 140. the control module 140 sends a second signal to the power module 110 according to the first signal, so as to increase the power voltage VB L at the output end of the power module 110, further reduce the voltage difference between the power voltage VB L at the output end of the power module 110 and the driving voltage required by the backlight module 150 (that is the voltage at the output end of the voltage boost module 120), further shorten the time required by the process of boosting the power voltage VB L to the driving voltage of the backlight module 150, improve the working efficiency of the voltage boost module, and avoid the serious working condition.
The embodiment of the utility model provides a drive circuit in a poor light includes power module, the module that steps up, compares module and control module. The comparison module is used for collecting the voltage of the output end of the boosting module, and when the collected voltage of the output end of the boosting module is increased to a preset value, the comparison module sends a first signal to the control module. The control module sends a second signal to the power module according to the first signal so as to improve the power supply voltage of the output end of the power module, further reduce the voltage difference between the power supply voltage of the output end of the power module and the driving voltage required by the backlight module (namely, the voltage of the output end of the boosting module), further shorten the time required by the process of boosting the power supply voltage to the driving voltage of the backlight module, improve the working efficiency of the boosting module, and avoid the situation that the boosting module generates heat seriously and even cannot work.
For better understanding of the embodiments of the present invention, the following description is provided to illustrate the backlight driving circuit according to the present invention with reference to the following embodiments:
fig. 2 is a schematic structural diagram of a backlight driving circuit according to an embodiment of the present invention, and this embodiment further embodies the module 130 on the basis of the above embodiment.
Illustratively, as shown in fig. 2, the comparing module 130 includes a comparing unit 131 and a first switching unit 132. A first input end of the comparison unit 131 is connected to an output end of the voltage boosting module 120, a second input end of the comparison unit 131 is used for accessing a reference voltage, and a voltage value of the reference voltage is a preset value. The comparing unit 131 is configured to send a conducting signal to the first switching unit 132 when the voltage of the first input terminal of the comparing unit 131 is greater than the reference voltage.
The output terminal of the comparison unit 131 is connected to the control terminal of the first switch unit 132, the first terminal of the first switch unit 132 is grounded, the second terminal of the first switch unit 132 is connected to the input terminal of the control module 140, the first switch unit 132 is configured to send a first signal to the control module 140 according to the turn-on signal, the control module 140 sends a second signal to the power module 110 according to the first signal, so as to increase the power voltage VB L at the output terminal of the power module 110, further reduce the voltage difference between the power voltage VB L at the output terminal of the power module 110 and the driving voltage required by the backlight module 150 (i.e., the voltage at the output terminal of the boost module 120), further shorten the time required by the process of boosting the power voltage VB L to the driving voltage of the backlight module 150, improve the working efficiency of the boost module, and avoid the situation that the boost circuit generates heat seriously or even cannot work.
For example, as shown in fig. 2, the comparing unit 130 includes a voltage comparator U305A, a first resistor R1, a second resistor R2, and a first capacitor C329. A first end of the first resistor R1 is connected to the output end of the voltage boost module 120, and a second end of the first resistor R1 is connected to the positive input end of the voltage comparator U305A. A first terminal of the second resistor R2 is connected to the positive input terminal of the voltage comparator U305A, and a second terminal of the second resistor R2 is grounded. The negative input of the voltage comparator U305A is used to input a reference voltage, which is illustratively 2.5V. A first terminal of the first capacitor C329 is connected to the negative input terminal of the voltage comparator U305A, and a second terminal of the first capacitor C329 is connected to ground. The first capacitor C329 has the function of voltage stabilization, the voltage value of the reference voltage is ensured to be stabilized to 2.5V, and the influence of the voltage fluctuation of the power grid on the reference voltage is avoided.
The voltage comparator U305A is configured to collect the voltage at the output terminal of the voltage boost module 120, compare the voltage with a reference voltage, and send a turn-on signal to the first switch unit 132 through the output terminal of the voltage comparator U305A when the voltage at the positive input terminal of the voltage comparator U305A is greater than the reference voltage. The first resistor R1 is a current-limiting resistor, so as to prevent the voltage comparator U305A from being damaged due to excessive current. The second resistor R2 is a voltage dividing resistor, the voltage of the first input terminal of the comparison unit 131 is the divided voltage of the second resistor R2, and the appropriate second resistor R2 can be selected to avoid the damage caused by the excessive voltage of the first input terminal of the voltage comparator U305A.
Of course, the voltage comparator U305A further includes a power input terminal and a ground terminal, the power input terminal of the voltage comparator U305A is used for accessing the operating power VCC of the voltage comparator U305A, and the ground terminal of the voltage comparator U305A is used for grounding.
The first switching unit 132 includes a first switching transistor QB6, a third resistor R3, a fourth resistor R4, and a fifth resistor R5. A first terminal of the third resistor R3 is connected to the output terminal of the comparing unit 131 (i.e., connected to the output terminal of the voltage comparator U305A), and a second terminal of the third resistor R3 is connected to the control terminal of the first switching transistor QB 6. A first terminal of the fourth resistor R4 is connected to the control terminal of the first switch transistor QB6, and a second terminal of the fourth resistor R4 is grounded. A first terminal of the first switching transistor QB6 is grounded, a second terminal of the first switching transistor QB6 is connected to a first terminal of a fifth resistor R5, and a second terminal of the fifth resistor R5 is connected to an input terminal of the control module 140.
When the voltage of the positive input terminal of the voltage comparator U305A is greater than the reference voltage, the output terminal of the voltage comparator U305A sends a turn-on signal to the control terminal of the first switch transistor QB6, where the turn-on signal may be a high level signal or a low level signal, so that the first switch transistor QB6 is turned on, and the fifth resistor R5 is connected to the circuit of the power module 110, that is, sends a second signal to the power module 110.
The third resistor R3 is a current-limiting resistor to prevent the control terminal of the first switch transistor QB6 from being damaged due to excessive current, and the fourth resistor R4 is a voltage-limiting resistor to prevent the control terminal of the first switch transistor QB6 from being damaged due to excessive voltage.
It should be noted that, in the embodiment shown in fig. 2, the first switching transistor QB6 is taken as an example to exemplify the technical solution of the present invention, and it should be clear to those skilled in the art that the first switching transistor QB6 may also be a MOS transistor, and the embodiment of the present invention is not limited herein.
Fig. 3 is a schematic structural diagram of another backlight driving circuit according to an embodiment of the present invention, and the present embodiment further embodies the control module 140 on the basis of the above embodiment.
Illustratively, as shown in fig. 3, the control module 140 includes a collection unit 141, a first control chip UB101, and a second switching unit 142. The input end of the acquisition unit 141 is connected to the output end of the comparison module 130, and the output end of the acquisition unit 141 is connected to the input end of the first control chip UB101 (i.e., the COMP pin of the first control chip UB 101). The collecting unit 141 is configured to send a feedback signal to the first control chip UB101 according to the first signal. An output terminal of the first control chip UB101 (i.e., a GATE pin of the UB 101) is connected to a control terminal of the second switching unit 142, and an output terminal of the second switching unit 142 is connected to the power module 110. The first control chip UB101 is configured to control the second switch unit 142 to send a second signal to the power module according to the feedback signal.
Illustratively, as shown in fig. 3, the acquisition unit 141 includes an optical coupler PCB101, a voltage reference chip UB102, a sixth resistor R6, and a seventh resistor R7., where the optical coupler PCB101 includes a light emitting portion PCB101A and a light sensing portion PCB101B, a first end of the optical coupler PCB101 (an anode of the light emitting portion PCB 101A) is used for inputting an optical coupler power VCC, a second end of the optical coupler PCB101 (a cathode of the light emitting portion PCB 101A) is connected to the first end of the voltage reference chip UB102, a second end of the voltage reference chip UB102 is grounded, a third end of the optical coupler PCB101 (a ground end of the light sensing portion PCB 101B) is grounded, a fourth end of the optical coupler PCB101 (an output end of the light sensing portion PCB 101B) is connected to an input end of the first control chip UB101, a third end of the voltage reference chip UB 865 102 is connected to an output end of the comparison module 130, a first end of the seventh resistor R7 is connected to an output end of the power module 110, a second end of the comparison module 7 is connected to an output end of the comparison module 130, a third end of the sixth resistor R4 is connected to the voltage reference chip 102, and the reference chip L is connected to the voltage reference chip 102, the third end of the reference chip 102 is connected to the voltage reference chip L.
Illustratively, the acquisition unit 141 further includes a resistor RB131, a resistor RB132, a resistor RB133, a capacitor CB109, a capacitor CB110, a capacitor CB103, and a resistor RB 104. The resistor RB131 has a first end for inputting the optocoupler power VCC, and a second end connected to the anode of the light emitting part PCB 101A. The resistance RB132 is connected in parallel with the light emitting section PCB 101A. A first terminal of the capacitor CB109 is connected to the cathode of the light emitting section PCB101A, a second terminal of the capacitor CB109 is connected to a first terminal of the resistor RB133, and a second terminal of the resistor RB133 is connected to a second terminal of the seventh resistor R7. A first terminal of the capacitor CB110 is connected to the cathode of the light emitting part PCB101A, and a second terminal of the capacitor CB110 is connected to a second terminal of the seventh resistor R7. A first end of the capacitor CB103 is connected with a COMP pin of the first control chip UB101, and a second end of the capacitor CB103 is grounded. The first end of the resistor RB104 is connected with an idle pin NC of the first control chip UB101, and the second end of the resistor RB104 is connected with the ground. The resistor RB131 serves as a protection resistor to prevent damage due to excessive current in the light emitting part PCB 101A. The capacitor CB103 serves as a protective capacitor to prevent the light sensing portion PCB101B from being damaged due to an excessive voltage. The capacitor CB109 and the capacitor CB110 are isolation capacitors.
Illustratively, as shown in fig. 3, the second switching unit 142 includes a second switching transistor QB101, an eighth resistor RB106, a ninth resistor RB148, and a second capacitor CB 116. A first terminal of the eighth resistor RB106 is connected to the output terminal of the first control chip UB101, and a second terminal of the eighth resistor RB106 is connected to the control terminal of the second switching transistor QB 101. A first terminal of the second switching transistor QB101 is connected to the power module 110, a second terminal of the second switching transistor QB101 is connected to a first terminal of a ninth resistor RB148, and a second terminal of the ninth resistor RB148 is grounded. A first terminal of the second capacitor CB116 is connected to the first terminal of the second switching transistor QB101, and a second terminal of the second capacitor CB116 is connected to the second terminal of the second switching transistor QB 101.
The eighth resistor RB106 is a current-limiting resistor, so as to prevent the control terminal of the second switching transistor QB101 from being damaged due to an excessive current. The ninth resistor RB148 is a current limiting resistor to prevent the second switch transistor QB101 from being damaged due to an excessive current. The second capacitor CB116 is a protection capacitor, and prevents the first terminal and the second terminal of the second switching transistor QB101 from being damaged due to an excessive voltage.
Illustratively, the first control chip UB101 may include peripheral circuits, which may include a resistor RB103, a resistor RB110, a capacitor CB101, a capacitor CB102, a regulator ZDB1, and a regulator ZDB 2. The first end of the resistor RB103 is connected with a chip selection pin CS of the first control chip UB101, and the second end of the resistor RB103 is grounded. A first end of the capacitor CB101 is connected with a chip selection pin CS of the first control chip UB101, and a second end of the capacitor CB101 is grounded. A first terminal of the capacitor CB102 is connected to the power supply pin VCC of the first control chip UB101, and a second terminal of the capacitor CB102 is grounded. And the resistor voltage-regulator tube ZDB1 and the voltage-regulator tube ZDB2 are connected in parallel, and one end of the parallel connected voltage-regulator tube ZDB1 is connected with a power supply pin VCC of the first control chip UB 101.
Specifically, when the voltage at the output end of the voltage boosting module 120 collected by the comparison module 130 is increased to a preset value, the comparison module 130 sends a first signal to the control module 140, and then the comparison module 130 is connected to a circuit where the collection unit 141 is located, so that the divided voltage of the sixth resistor R6 (i.e., the voltage at the third end of the voltage reference chip UB 102) is reduced and lower than the reference voltage, the impedance from the first end to the second end of the voltage reference chip UB102 is increased, the current flowing through the light emitting part PCB101A is reduced, the luminance of the light emitting part PCB101A is reduced, the impedance of the light sensing part PCB101B is increased, the current of the light sensing part PCB101 is reduced, the first control chip UB101 detects the current change and sends a control signal to the second switching transistor QB 101.
It should be noted that, in the embodiment shown in fig. 3, the second switching transistor QB101 is taken as an MOS transistor as an example to exemplarily explain the technical solution of the present invention, and it should be clear to those skilled in the art that the second switching transistor QB101 may also be a triode, and the embodiment of the present invention is not limited herein.
Fig. 4 is a schematic structural diagram of another backlight driving circuit according to an embodiment of the present invention, and the present embodiment further embodies the boosting module 120 on the basis of the above embodiment.
Illustratively, as shown in fig. 4, the boost module 120 includes a boost unit 121 and a second control chip UB 801. The input end of the voltage boosting unit 121 is connected to the output end of the power module 110, and the output end of the voltage boosting unit 121 is used for connecting the backlight module 150. The output end of the second control chip UB801 is connected to the control end of the boosting unit 121.
Illustratively, as shown in fig. 4, the boosting unit 121 includes a diode DB801, a third switching transistor QB801, an inductor L B801, and an electrolytic capacitor eb802, wherein a first terminal of the inductor L B801 is connected to the output terminal of the power module 110, a second terminal of the inductor L B801 is connected to the anode of the diode DB801, and a cathode of the diode DB801 is connected to the backlight module 150, a first terminal of the electrolytic capacitor EB802 is connected to the cathode of the diode DB801, and a second terminal of the electrolytic capacitor EB802 is grounded, a first terminal of the third switching transistor QB801 is connected to a second terminal of the inductor L B801, a second terminal of the third switching transistor QB801 is used for receiving a reference level (e.g., a low level), and a control terminal of the third switching transistor QB801 is connected to the output terminal of the second control chip UB801 (i.e., the GATE pin of the second control chip UB 801).
Specifically, the third switching transistor QB801 is an nmos transistor, the GATE pin of the second control chip UB801 outputs a stable PWM signal, the third switching transistor QB801 is turned on in a high level period of the PWM signal, the inductor L B801 is charged with the voltage VB L at the output terminal of the power module 110, the electrolytic capacitor EB802 is discharged, the backlight module 150 is maintained to operate, the diode DB801 is turned off, the inductor L B801 is discharged in a low level period of the PWM signal, the electrolytic capacitor EB802 is charged, and the voltage is supplied to the electrolytic capacitor EB802 by the backlight module 15 before the electrolytic capacitor EB802 is charged, so that the voltage across the electrolytic capacitor EB802 is increased, and the boosting function is realized.
For example, the boosting unit 121 may further include a resistor RB807, a resistor RB808, and a resistor RB 820. One end of the resistor RB807 is connected to the control end of the third switching transistor QB801, and the other end is connected to the GATE pin of the second control chip UB 801. One end of the resistor RB808 is connected to the control terminal of the third switching transistor QB801, and the other end is connected to the second terminal of the third switching transistor QB 801. One end of the resistor RB820 is connected to the second end of the third switching transistor QB801, and the other end is grounded. The resistor RB807 serves as a protection resistor to prevent the control terminal of the third switching transistor QB801 from being damaged due to excessive current. The resistor RB808 serves as a protection resistor to prevent the control terminal of the third switching transistor QB801 from being damaged due to an excessive voltage difference between the control terminal and the second terminal. The resistor RB820 serves as a protection resistor to prevent the third switching transistor QB801 from being damaged due to an excessive current.
For example, the boosting unit 121 may further include a resistor RB814, a resistor RB815 and a resistor RB 817. A first end of the resistor RB814 is connected to the cathode of the diode DB801, a second end of the resistor RB814 is connected to a first end of the resistor RB815, and a second end of the resistor RB815 is connected to the feedback pin FB of the second control chip UB 801. A first end of the resistor RB817 is connected with the cathode of the diode DB801, and a second end of the resistor RB817 is connected with an overvoltage protection detection pin OVP of the second control chip UB 801. When detecting that the voltage at the output terminal of the boosting unit 121 is too high, the second control chip UB801 stops outputting the PWM signal to the control terminal of the third switching transistor QB801, thereby preventing the backlight module 150 from being damaged due to overvoltage.
It should be noted that the second control chip UB801 may include a peripheral circuit, and the peripheral circuit may include a resistor RB801, a resistor RB803, a capacitor CB801, a resistor RB8013, a resistor RB804, a resistor RB805, a resistor RB806, a capacitor CB803, and a capacitor CB 805. A first end of the resistor RB801 is connected to a PWM pin of the second control chip UB801, and a second end of the resistor RB801 is used to output a PWM signal, which is used to adjust the light of the backlight module 150. A first end of the resistor RB803 is connected to the overvoltage protection detection pin OVP of the second control chip UB801, and a second end of the resistor RB803 is grounded. A first terminal of the capacitor CB801 is connected to the power supply pin VIN of the second control chip UB801, and a second terminal of the capacitor CB801 is grounded. A first end of the capacitor CB803 is connected with a chip selection pin CS of the second control chip UB801, and a second end of the capacitor CB803 is grounded. A first terminal of resistor RB8013 is coupled to a second terminal of third switching transistor QB801, and a second terminal of resistor RB8013 is coupled to a first terminal of capacitor CB 803. The first end of the resistor RB805 is connected with the feedback pin FB of the second control chip UB801, the second end of the resistor RB805 is grounded, and the resistor RB806 is connected with the resistor RB805 in parallel. The first end of the resistor RB804 is connected with an external loop compensation pin COMP of the second control chip UB801, the second end of the resistor RB804 is connected with the first end of the capacitor CB805, and the second end of the capacitor CB805 is grounded.
It should be noted that, in the embodiment shown in fig. 4, the third switching transistor QB801 is taken as an MOS transistor as an example to exemplarily explain the technical solution of the present invention, and it should be clear to those skilled in the art that the third switching transistor QB801 may also be a triode, and the embodiment of the present invention is not limited herein.
Fig. 5 is a circuit diagram of a backlight driving circuit according to an embodiment of the present invention, and the present embodiment further illustrates the technical solution of the present invention on the basis of the foregoing embodiment.
As shown in fig. 5, on the basis of the above-described embodiment, the power supply module 110 includes the transformer TB101, and the transformer TB101 includes the first winding coil, the second winding coil, and the third winding coil.
A first end of the first winding coil is connected to the output end Vbridge of the rectifier bridge (not shown in the figure), and a second end of the first winding coil is connected to the output end of the control module 140 (i.e., the first end of the second switching transistor QB 101). Power module 110 also includes electrolytic capacitor EB1, resistor RB117, resistor RB118, resistor RB123, capacitor CB114, and diode DB 106. One end of the electrolytic capacitor EB1 is connected with the output end Vbridge of the rectifier bridge, and the other end is grounded. Resistor RB117 and resistor RB118 are connected in parallel, one end of resistor RB117 and resistor RB118 are both connected with the first end of electrolytic capacitor EB1, the other end of resistor RB117 and resistor RB118 are both connected with one end of capacitor CB114, the other end of capacitor CB114 is connected with the cathode of diode DB106, and the anode of diode DB106 is connected with the first end of second switching transistor QB 101. Resistor RB123 has a first end connected to a first end of electrolytic capacitor EB1, and has the other end connected to the cathode of diode DB 106. The electrolytic capacitor EB1 and the capacitor CB114 are used for stabilizing the voltage at the output terminal Vbridge of the rectifier bridge.
The first end of the second winding coil is connected with the rectifying and filtering circuit, the second end of the second winding coil is grounded, the rectifying and filtering circuit comprises a diode DB103, a capacitor CB118 and a resistor RB130, the anode of the diode DB103 is connected with the first end of the second winding coil, the cathode of the diode DB103 is connected with the first end of the inductor L B801, the first end of the capacitor CB118 is connected with the first end of the second winding coil, the second end of the capacitor RB130 is connected with the first end of the resistor RB130, the second end of the resistor RB130 is connected with the input end of the boost module 120 (namely the first end of the inductor L B801), the power supply module 110 further comprises an electrolytic capacitor EB104, the first end of the electrolytic capacitor EB104 is connected with the first end of the inductor L B801, the second end of the electrolytic capacitor EB104 is grounded, and the electrolytic capacitor EB104 serves as a voltage stabilizing capacitor and is used for maintaining the stability of.
A first end of the third winding coil is connected to a first end of a resistor RB114, a second end of the resistor RB114 is connected to a first end of a resistor RB115, a second end of the resistor RB115 is connected to an anode of a diode DB104, a cathode of the diode DB104 is connected to a first end of an electrolytic capacitor EB106, a second end of the electrolytic capacitor EB106 is grounded, and a diode DB105 is connected in parallel to the diode DB 104. A first end of capacitor CB115 is connected to a second end of resistor RB115, a second end of capacitor CB115 is connected to a first end of resistor RB111, and a second end of resistor RB111 is connected to a first end of electrolytic capacitor EB 106. A first end of the resistor RB110 is connected to a power supply pin VCC of the first control chip UB101, and a second end of the resistor RB110 is connected to a first end of the electrolytic capacitor EB 106.
Specifically, the voltage of the third winding coil is shaped and filtered by the diode DB105, the diode DB104, the capacitor CB115 and the resistor RB111, and supplies power to the first control chip UB 101. The electrolytic capacitor EB106 is used to maintain the stability of the voltage input to the power supply pin VCC of the first control chip UB 101.
Specifically, the first winding coil of the power supply module receives the voltage input by the rectifier bridge, and the voltage is converted (boosted or reduced) by the second winding coil, rectified and filtered by the diode DB103 and the capacitor CB118, and forms the power supply voltage VB L.
Specifically, the GATE pin of the second control chip UB801 outputs a stable PWM signal, the third switching transistor QB801 is turned on in a high level section of the PWM signal, the voltage VB L at the output terminal of the power module 110 charges the inductor L B801, the electrolytic capacitor EB802 discharges, the backlight module 150 maintains the operation of the diode DB801, the diode DB801 is turned off in a low level section of the PWM signal, the third switching transistor QB801 is turned off, the inductor L B801 discharges, the electrolytic capacitor EB802 charges, the backlight module 15 has the electrolytic capacitor EB802 supplying voltage before the electrolytic capacitor EB802 is charged, and thus the voltage across the electrolytic capacitor EB802 increases, thereby implementing the boosting function.
When the liquid crystal device becomes bigger, that is, the L ED lamp beads of the backlight module increase in number, the driving voltage required by the backlight module also increases correspondingly, and the voltage output by the boosting module increases correspondingly.
Specifically, when the voltage of the positive input end of the voltage comparator U305A is greater than the reference voltage, the output end of the voltage comparator U305A sends a conducting signal to the control end of the first switching transistor QB6, the conducting signal may be a high level signal or a low level signal, so that the first switching transistor QB6 is turned on, and the fifth resistor R5 is connected to the circuit of the power module 110, the fifth resistor R5 is connected in parallel to the sixth resistor R6, so that the voltage division of the sixth resistor R6 (i.e., the voltage at the third end of the voltage reference chip UB 102) is reduced and lower than the reference voltage, the impedance from the first end to the second end of the voltage reference chip UB102 is increased, the current flowing through the light emitting part PCB101A is reduced, the on-off brightness of the PCB A is reduced, the impedance of the light sensing part 101 is increased, the light sensing part 101 of the light sensing part UB101 is reduced, and the current of the light sensing part UB101 is increased and the power supply winding B sends a second signal to the control module (the second power supply winding) to control module QB101, and the second switching transistor QB L).
In addition, when the liquid crystal device is in standby, the backlight module does not work, the power supply voltage VB L has the problem that the power supply voltage VB L is floated when the power supply voltage VB L is higher than the working voltage of the backlight module due to the fact that the power supply voltage is output by a transformer, the backlight module can not work, or the current of the backlight module exceeds the rated current of L ED lamp beads at the moment of starting, and the L ED lamp beads are damaged.
The embodiment of the utility model provides a backlight driving circuit, in the standby of liquid crystal display equipment, there is mains voltage VB L when floating high when empty, sixth resistance R6's partial pressure increases, be higher than reference voltage, the impedance of voltage reference chip UB102 first end to second end diminishes, the current that flows illuminating part PCB101A increases, illuminating part PCB 101A's luminous brightness increase, the impedance of light-sensitive part PCB101B reduces, light-sensitive part PCB 101B's current increase first control chip UB101 detects this current change, send the PWM signal to second switch transistor QB101, the on-off time of control second switch transistor QB101 (send the second signal to power module 110 promptly), reduce power module's the voltage of first winding coil, and then reduce power module's the voltage of second winding coil (be mains voltage VB L) thereby when avoiding empty load to start, mains voltage VB L voltage is higher than the operating voltage of backlight module, cause backlight module not work, or start in the twinkling of an eye the moment backlight module's current surpasss current exceeds L ED lamp pearl 24, the rated current L causes the rated load condition.
The embodiment of the utility model provides a backlight driving circuit includes power module, boost module, compare module and control module, compare the module and be used for gathering the voltage of boost module's output, when the voltage of the output of the boost module who gathers increases to the default, compare the module and send first signal to control module, control module is according to this first signal, send the second signal to power module, with the mains voltage who improves power module's output, and then reduce the mains voltage of power module's output and the voltage difference of the required driving voltage of backlight module (the voltage of the output of boost module promptly), and then shortened the required time of mains voltage boost to backlight module's driving voltage's process, improve boost module's work efficiency, it is serious to avoid boost circuit to generate heat, the condition that can't work even, in addition, when avoiding the unloaded start-up, mains voltage VB L voltage is higher than backlight module's operating voltage, cause backlight module not work, or the electric current that starts the instantaneous backlight module surpasss lamp pearl exceeds L rated current, cause the condition that L ED damages.
The utility model also provides an electronic equipment, it is exemplary, this electronic equipment can be liquid crystal display devices such as intelligent TV set. This electronic equipment includes the utility model discloses the drive circuit is shaded that arbitrary embodiment provided, this drive circuit is shaded includes power module, the module that steps up, compares module and control module.
The output end of the power supply module is connected with the input end of the boosting module, and the output end of the boosting module is used for being connected with the backlight module.
The input end of the comparison module is connected with the output end of the boosting module, and the output end of the comparison module is connected with the input end of the control module; the comparison module is used for collecting the voltage of the output end of the boosting module and sending a first signal to the control module based on the voltage of the output end of the boosting module.
The output end of the control module is connected with the power supply module, and the control module is used for sending a second signal to the power supply module according to the first signal so as to improve the power supply voltage of the output end of the power supply module.
The embodiment of the utility model provides an electronic equipment is used for gathering the voltage of the output of the module that steps up through comparing the module, when the voltage of the output of the module that steps up who gathers increases to the default, compares the module and sends first signal to control module. The control module sends a second signal to the power supply module according to the first signal so as to improve the power supply voltage of the output end of the power supply module, further reduce the voltage difference between the power supply voltage of the output end of the power supply module and the driving voltage required by the backlight module (namely, the voltage of the output end of the boosting module), further shorten the time required by the process of boosting the power supply voltage to the driving voltage of the backlight module, improve the working efficiency of the boosting module, and avoid the situation that the boosting circuit generates heat seriously or even cannot work.
In the description herein, it is to be understood that the terms "upper", "lower", "right", and the like are used in an orientation or positional relationship based on that shown in the drawings for convenience of description and simplicity of operation, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used merely for descriptive purposes and are not intended to have any special meaning.
In the description herein, references to the description of "an embodiment," "an example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be appropriately combined to form other embodiments as will be appreciated by those skilled in the art.
The technical principle of the present invention is described above with reference to specific embodiments. The description is made for the purpose of illustrating the principles of the invention and should not be construed in any way as limiting the scope of the invention. Based on the explanations herein, those skilled in the art will be able to conceive of other embodiments of the present invention without any inventive effort, which would fall within the scope of the present invention.
Claims (10)
1. A backlight driving circuit, comprising: the device comprises a power supply module, a boosting module, a comparison module and a control module;
the output end of the power supply module is connected with the input end of the boosting module, and the output end of the boosting module is used for being connected with the backlight module;
the input end of the comparison module is connected with the output end of the boosting module, and the output end of the comparison module is connected with the input end of the control module; the comparison module is used for acquiring the voltage of the output end of the boosting module and sending a first signal to the control module based on the voltage of the output end of the boosting module;
the output end of the control module is connected with the power supply module, and the control module is used for sending a second signal to the power supply module according to the first signal so as to improve the power supply voltage of the output end of the power supply module.
2. The backlight driving circuit according to claim 1, wherein the comparing module comprises a comparing unit and a first switch unit;
the first input end of the comparison unit is connected with the output end of the boosting module, and the second input end of the comparison unit is used for accessing a reference voltage; the comparison unit is used for sending a conducting signal to the first switch unit when the voltage of the first input end of the comparison unit is greater than the reference voltage;
the output end of the comparison unit is connected with the control end of the first switch unit, the first end of the first switch unit is grounded, and the second end of the first switch unit is connected with the input end of the control module; the first switch unit is used for sending the first signal to the control module according to the conducting signal.
3. The backlight driving circuit according to claim 2, wherein the comparing unit comprises a voltage comparator, a first resistor, a second resistor and a first capacitor;
the first end of the first resistor is connected with the output end of the boosting module, and the second end of the first resistor is connected with the positive input end of the voltage comparator;
the first end of the second resistor is connected with the positive input end of the voltage comparator, and the second end of the second resistor is grounded;
the negative input end of the voltage comparator is used for inputting the reference voltage;
the first end of the first capacitor is connected with the negative input end of the voltage comparator, and the second end of the first capacitor is grounded.
4. The backlight driving circuit according to claim 2, wherein the first switching unit comprises a first switching transistor, a third resistor, a fourth resistor, and a fifth resistor;
the first end of the third resistor is connected with the output end of the comparison unit, and the second end of the third resistor is connected with the control end of the first switch transistor;
a first end of the fourth resistor is connected with the control end of the first switching transistor, and a second end of the fourth resistor is grounded;
a first end of the first switch transistor is grounded, and a second end of the first switch transistor is connected with a first end of the fifth resistor;
and the second end of the fifth resistor is connected with the input end of the control module.
5. The backlight driving circuit according to claim 1, wherein the control module comprises an acquisition unit, a first control chip and a second switch unit;
the input end of the acquisition unit is connected with the output end of the comparison module, and the output end of the acquisition unit is connected with the input end of the first control chip; the acquisition unit is used for sending a feedback signal to the first control chip according to the first signal;
the output end of the first control chip is connected with the control end of the second switch unit, and the output end of the second switch unit is connected with the power supply module; the first control chip is used for controlling the second switch unit to send the second signal to the power module according to the feedback signal.
6. The backlight driving circuit according to claim 5, wherein the collecting unit comprises an optical coupler, a voltage reference chip, a sixth resistor and a seventh resistor;
the first end of the optical coupler is used for inputting an optical coupler power supply, the second end of the optical coupler is connected with the first end of the voltage reference chip, and the second end of the voltage reference chip is grounded;
the third end of the optical coupler is grounded, and the fourth end of the optical coupler is connected with the input end of the first control chip;
the third end of the voltage reference chip is connected with the output end of the comparison module;
the first end of the seventh resistor is connected with the output end of the power supply module, and the second end of the seventh resistor is connected with the output end of the comparison module;
and the first end of the sixth resistor is connected with the third end of the voltage reference chip, and the second end of the sixth resistor is grounded.
7. The backlight driving circuit according to claim 5, wherein the second switching unit comprises a second switching transistor, an eighth resistor, a ninth resistor, and a second capacitor;
a first end of the eighth resistor is connected with the output end of the first control chip, and a second end of the eighth resistor is connected with the control end of the second switching transistor;
a first end of the second switching transistor is connected with the power supply module, and a second end of the second switching transistor is connected with a first end of the ninth resistor;
a second end of the ninth resistor is grounded;
the first end of the second capacitor is connected with the first end of the second switch transistor, and the second end of the second capacitor is connected with the second end of the second switch transistor.
8. The backlight driving circuit according to claim 1, wherein the boosting module comprises a boosting unit and a second control chip;
the input end of the boosting unit is connected with the output end of the power supply module, and the output end of the boosting unit is used for being connected with the backlight module;
and the output end of the second control chip is connected with the control end of the boosting unit.
9. The backlight driving circuit according to claim 8, wherein the boosting unit includes a diode, a third switching transistor, an inductor, and an electrolytic capacitor;
the first end of the inductor is connected with the output end of the power supply module, and the second end of the inductor is connected with the anode of the diode;
the cathode of the diode is connected with the backlight module;
the first end of the electrolytic capacitor is connected with the cathode of the diode, and the second end of the electrolytic capacitor is grounded;
the first end of the third switching transistor is connected with the second end of the inductor, the second end of the third switching transistor is used for accessing a reference level, and the control end of the third switching transistor is connected with the output end of the second control chip.
10. An electronic device comprising the backlight driving circuit according to any one of claims 1 to 9.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922095825.7U CN211087888U (en) | 2019-11-27 | 2019-11-27 | Backlight driving circuit and electronic equipment |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201922095825.7U CN211087888U (en) | 2019-11-27 | 2019-11-27 | Backlight driving circuit and electronic equipment |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111883085A (en) * | 2020-09-28 | 2020-11-03 | 南京熊猫电子制造有限公司 | Device for improving stable work of liquid crystal equipment |
| CN113744695A (en) * | 2021-08-04 | 2021-12-03 | 青岛鼎信通讯股份有限公司 | Low-cost LED backlight control circuit applied to station terminal |
-
2019
- 2019-11-27 CN CN201922095825.7U patent/CN211087888U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111883085A (en) * | 2020-09-28 | 2020-11-03 | 南京熊猫电子制造有限公司 | Device for improving stable work of liquid crystal equipment |
| CN113744695A (en) * | 2021-08-04 | 2021-12-03 | 青岛鼎信通讯股份有限公司 | Low-cost LED backlight control circuit applied to station terminal |
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