CN211062443U - Module backlight control circuit and television - Google Patents
Module backlight control circuit and television Download PDFInfo
- Publication number
- CN211062443U CN211062443U CN201922095235.4U CN201922095235U CN211062443U CN 211062443 U CN211062443 U CN 211062443U CN 201922095235 U CN201922095235 U CN 201922095235U CN 211062443 U CN211062443 U CN 211062443U
- Authority
- CN
- China
- Prior art keywords
- circuit
- control circuit
- electrically connected
- resistor
- dimming
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
The embodiment of the utility model discloses a module backlight control circuit and a television, the module backlight control circuit comprises a transformer, a rectifying and filtering circuit, a dimming control circuit, a signal matching circuit, a voltage conversion circuit and a main control circuit, and the input end of the transformer is connected with an alternating voltage; the input end of the rectification filter circuit is electrically connected with the output end of the transformer; the input end of the voltage conversion circuit is electrically connected with the first output end of the rectification filter circuit, the output end of the voltage conversion circuit is electrically connected with the first electrode of the backlight lamp strip, the enabling and dimming signal input ends of the dimming control circuit are electrically connected with the PWM signal output end of the main control circuit through the signal matching circuit, and the driving end of the dimming control circuit is electrically connected with the control end of the voltage conversion circuit. The embodiment of the utility model provides a under the condition of the enable signal input part who omits dimming control circuit, through signal matching circuit, solved the problem that the start flickers the screen, and under the reduce system cost, improved module backlight control circuit's stability.
Description
Technical Field
The embodiment of the utility model provides a relate to backlight display technical field, especially relate to a module backlight control circuit and TV set.
Background
At present, the current control of a module light bar is realized by adopting a constant current chip in the control of a television module backlight system, and meanwhile, in the starting process of the module backlight light bar, after a constant current chip power supply system is established, the starting and dimming functions of the constant current system are realized through an enabling pin and a dimming pin, namely, a television main chip needs to be provided with two I/O ports to realize communication with the constant current chip, so that the control of the backlight chip is realized according to a certain time sequence requirement, and the control requirement of the backlight of a system module of display equipment is met. However, the development cost of the system chip is high, which is not favorable for simplifying resources.
SUMMERY OF THE UTILITY MODEL
An embodiment of the utility model provides a module backlight control circuit and TV set to the power that the solution simplified the electric current control chip and brought flashes the screen problem, and reduce cost.
In a first aspect, an embodiment of the present invention provides a module backlight control circuit, including: the device comprises a transformer, a rectifying and filtering circuit, a dimming control circuit, a signal matching circuit, a voltage conversion circuit and a main control circuit;
the transformer comprises an input end and an output end, and the input end of the transformer is connected with an alternating voltage;
the rectifier filter circuit comprises an input end and a first output end, and the input end of the rectifier filter circuit is electrically connected with the output end of the transformer;
the voltage conversion circuit comprises an input end, an output end and a control end, the input end of the voltage conversion circuit is electrically connected with the first output end of the rectification filter circuit, the output end of the voltage conversion circuit is electrically connected with the first electrode of the backlight lamp bar, and the voltage conversion circuit is used for converting the voltage output by the first output end of the rectification filter circuit into the voltage matched with the backlight lamp bar;
the dimming control circuit comprises an enabling and dimming signal input end, an output end and a driving end, the enabling and dimming signal input end of the dimming control circuit is connected with the PWM signal output end of the main control circuit through the signal matching circuit, the output end of the dimming control circuit is connected with the second pole of the backlight lamp strip, the driving end of the dimming control circuit is connected with the control end of the voltage conversion circuit, and the signal matching circuit is used for matching the enabling and dimming signal input end of the dimming control circuit and the impedance of the PWM signal output end of the main control circuit.
Optionally, the signal matching circuit includes a first resistor, a second resistor, and a third resistor;
the first end of the first resistor is electrically connected with the enabling and dimming signal input end of the dimming control circuit, the second end of the first resistor is grounded, the first end of the second resistor is electrically connected with the first end of the first resistor, the second end of the second resistor is electrically connected with the PWM signal output end of the main control circuit, the first end of the third resistor is electrically connected with the second end of the second resistor, and the second end of the third resistor is grounded.
Optionally, the signal matching circuit further includes a first capacitor;
the first end of the first capacitor is electrically connected with the enabling and dimming signal input end of the dimming control circuit, and the second end of the first capacitor is grounded.
Optionally, the signal matching circuit further includes a first diode and a fourth resistor, and the main control circuit further includes an enable signal output terminal;
the anode of the first diode is electrically connected with the enabling and dimming signal input end of the dimming control circuit, and the cathode of the first diode is electrically connected with the enabling signal output end of the main control circuit;
the first end of the fourth resistor is electrically connected with the cathode of the first diode, and the second end of the fourth resistor is grounded.
Optionally, the dimming control circuit includes a current control chip, the current control chip includes a power supply terminal, an enable and dimming signal input terminal, a voltage output terminal and a constant current drive terminal, and the rectification filter circuit further includes a second output terminal;
the power supply end of the current control chip is electrically connected with the second output end of the rectification filter circuit, the enabling and dimming signal input ends of the current control chip are electrically connected with the first end of the first resistor, the constant current driving end of the current control chip is electrically connected with the control end of the voltage conversion circuit, and the voltage output end of the current control chip is electrically connected with the negative electrode of the backlight lamp bar;
and the enable and dimming signal input ends of the current control chip multiplex an enable signal and a dimming signal.
Optionally, the voltage conversion circuit includes a fifth resistor, a first switching tube, a second diode, a first inductor, and a second capacitor;
a first end of the fifth resistor is electrically connected with a constant-current driving end of the current control chip, a second end of the fifth resistor is electrically connected with a first pole of the first switch tube, a second pole of the first switch tube is electrically connected with an anode of the second diode, and a third pole of the first switch tube is grounded;
the cathode of the second diode is electrically connected with the first pole of the backlight lamp bar, and the second pole of the backlight lamp bar is electrically connected with the voltage output end of the current control chip;
the first end of the first inductor is electrically connected with the first output end of the rectifying and filtering circuit, and the second end of the first inductor is electrically connected with the second pole of the first switch tube;
the first end of the second capacitor is electrically connected with the first pole of the backlight lamp bar, and the second end of the second capacitor is grounded.
Optionally, the dimming control circuit further includes a driving circuit, and the driving circuit includes a sixth resistor, a seventh resistor, a third capacitor, and a fourth capacitor; the current control chip also comprises a current control end and a current compensation end;
the first end of the sixth resistor is electrically connected with the current control end of the current control chip, and the second end of the sixth resistor is grounded;
the first end of the seventh resistor is electrically connected with the current compensation end of the current control chip, the second end of the seventh resistor is grounded through the third capacitor, and the current compensation end of the current control chip is grounded through the fourth capacitor.
Optionally, the output end of the transformer includes a first output end and a second output end, and the rectifying and filtering circuit includes a first rectifying and filtering circuit and a second rectifying and filtering circuit;
the first rectifying and filtering circuit comprises a third diode and a fifth capacitor;
the anode of the third diode is electrically connected with the first output end of the transformer, the cathode of the third diode is electrically connected with the first end of the first inductor, the first end of the fifth capacitor is electrically connected with the cathode of the third diode, and the second end of the fifth capacitor is grounded;
the second rectifying and filtering circuit comprises a fourth diode and a sixth capacitor;
an anode of the fourth diode is electrically connected with the second output end of the transformer, a cathode of the fourth diode is electrically connected with a power supply end of the current control chip, a first end of the sixth capacitor is electrically connected with a cathode of the fourth diode, and a second end of the sixth capacitor is grounded.
Optionally, the module backlight control circuit further comprises a DC/DC circuit, and the main control circuit further comprises a power supply terminal; the input end of the DC/DC circuit is electrically connected with the second output end of the rectification filter circuit, and the output end of the DC/DC circuit is electrically connected with the power supply end of the main control circuit.
In a second aspect, the embodiment of the present invention further provides a television, including the backlight control circuit of the module.
The embodiment of the utility model provides a technical scheme, PWM dimming signal that combines master control circuit's PWM signal output part through signal matching circuit matches dimming control circuit's the messenger and the signal of dimming signal input part, adopt two IO mouths and dimming control circuit to use an IO mouth to communicate through master control circuit, realize dimming control circuit's the messenger and the function of dimming signal simultaneous control, through signal matching circuit realization master control circuit's PWM signal output part and messenger's end and dimming control circuit's messenger and the voltage matching between the dimming signal input part promptly. Therefore, compared with the prior art, the embodiment of the utility model provides a under the condition of the enable signal input part who omits dimming control circuit, through dimming control circuit and master control circuit's matching, the problem of the start splash screen has been solved, and under the reduce system cost, has improved module backlight control circuit's stability.
Drawings
Fig. 1 is a schematic structural diagram of a backlight control circuit of a module according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of another backlight control circuit module according to an embodiment of the present invention
Fig. 3 is a schematic structural diagram of another module backlight control circuit provided in an embodiment of the present invention;
FIG. 4 is a schematic diagram of another backlight control circuit module according to an embodiment of the present invention
Fig. 5 is a schematic structural diagram of another module backlight control circuit provided in an embodiment of the present invention;
fig. 6 is a schematic structural diagram of another module backlight control circuit according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic structural diagram of a backlight control circuit of a module according to an embodiment of the present invention, wherein the backlight control circuit of the module can be applied to a voltage range of 100-240 VAC. Referring to fig. 1, the module backlight control circuit includes: the device comprises a transformer 10, a rectifying and filtering circuit 20, a dimming control circuit 40, a signal matching circuit 50, a voltage conversion circuit 30 and a main control circuit 60;
the transformer 10 comprises an input end A1 and an output end A2, and an input end A1 end of the transformer 10 is connected with an alternating voltage;
the rectifying and filtering circuit 20 comprises an input end B1 and a first output end B2, and the input end B1 of the rectifying and filtering circuit 20 is electrically connected with the output end A2 of the transformer 10;
the voltage conversion circuit 30 comprises an input end C1, an output end C2 and a control end C3, the input end C1 of the voltage conversion circuit 30 is electrically connected with the first output end B2 of the rectifying and filtering circuit 20, the output end C2 of the voltage conversion circuit 30 is electrically connected with the first pole G1 of the backlight light bar 70, and the voltage conversion circuit 30 is used for converting the voltage output by the first output end B2 of the rectifying and filtering circuit 20 into the voltage matched with the backlight light bar 70;
the dimming control circuit 40 comprises an enable and dimming signal input end D1, an output end D2 and a driving end D3, the enable and dimming signal input end D1 of the dimming control circuit 40 is electrically connected with the PWM signal output end F1 of the main control circuit 60 through a signal matching circuit 50, the output end D2 of the dimming control circuit 40 is electrically connected with the second pole G2 of the backlight lamp bar 70, the driving end D3 of the dimming control circuit 40 is electrically connected with the control end C3 of the voltage conversion circuit 30, and the signal matching circuit 50 is used for matching the voltages of the enable and dimming signal input end D1 of the dimming control circuit 40 and the PWM signal output end F1 of the main control circuit 60.
Specifically, the input end a1 of the transformer 10 can input 100-240V ac power, and convert the input ac voltage into low-voltage ac power, and the rectifier and filter circuit 20 rectifies and filters the low-voltage ac power input by the input end B1, and converts the low-voltage ac power into the first dc voltage VOUT1 to supply power to the backlight lamp strip 70. When the rated voltage of the backlight light bar 70 is larger, the first direct current voltage VOUT1 is not enough to supply power to the backlight light bar 70, and the voltage conversion circuit 30 increases the first direct current voltage VOUT1 output by the first output terminal B2 of the rectifying and filtering circuit 20 to the voltage required by the backlight light bar 70, so as to light the backlight light bar 70.
The enable signal end and the dimming signal end of the dimming control circuit in the prior art are independently arranged and are respectively controlled by the enable signal end and the PWM dimming signal end of the main control circuit, when the dimming control circuit receives the high level output by the main control circuit, the dimming control circuit controls the backlight lamp bar to be lightened, the time sequence problem of the enable signal and the dimming signal does not exist, and the backlight lamp bar can be lightened as long as the dimming control circuit receives the high level output by the PWM signal end of the main control circuit in the state of the enable signal outputting the high level.
And the embodiment of the present invention omits the enable terminal from the dimming control circuit 40, the enable signal and the dimming signal share one enable and dimming signal input terminal D1, and the main control circuit still has two I/O ports, which are the PWM signal output terminal F1 and the enable signal output terminal (not shown in fig. 1). When the PWM signal output from the PWM signal output terminal F1 of the main control circuit 60 is at a high level, the enable and dimming signal input terminal D1 of the dimming control circuit needs to determine whether the high level signal is an enable signal, which causes a timing problem; when the display device, such as a television, is turned on, the main control circuit 60 will send out a transient pulse to make the display screen flash. By adding the signal matching circuit 50, the high level pulse output by the PWM signal output terminal F1 of the main control circuit 60 is pulled down when the computer is turned on, so that the enabling and dimming signal input terminals of the dimming control circuit 40 receive a low level, and the phenomenon of screen flashing does not occur. After the display screen is turned on, the PWM signal with fixed frequency is output from the PWM signal output terminal of the main control circuit 60, and at this frequency, human eyes cannot recognize the change condition of the display screen.
The embodiment of the utility model provides a technical scheme, PWM dimming signal that combines master control circuit's PWM signal output part through signal matching circuit matches dimming control circuit's the messenger and the signal of dimming signal input part, adopt two IO mouths and dimming control circuit to use an IO mouth to communicate through master control circuit, realize dimming control circuit's the messenger and the function of dimming signal simultaneous control, through signal matching circuit realization master control circuit's PWM signal output part and messenger's end and dimming control circuit's messenger and the voltage matching between the dimming signal input part promptly. Therefore, compared with the prior art, the embodiment of the utility model provides a under the condition of the enable signal input part who omits dimming control circuit, through dimming control circuit and master control circuit's matching, the problem of the start splash screen has been solved, and under the reduce system cost, has improved module backlight control circuit's stability.
Optionally, fig. 2 is a schematic structural diagram of another backlight control circuit of the module according to an embodiment of the present invention, and referring to fig. 2, the signal matching circuit 50 includes a first resistor R1, a second resistor R2, and a third resistor R3;
a first end of the first resistor R1 is electrically connected to the enable and dimming signal input end D1 of the dimming control circuit 40, a second end of the first resistor R1 is grounded, a first end of the second resistor R2 is electrically connected to a first end of the first resistor R1, a second end of the second resistor R2 is electrically connected to the PWM signal output end F1 of the main control circuit 60, a first end of the third resistor R3 is electrically connected to a second end of the second resistor R2, and a second end of the third resistor R3 is grounded.
Specifically, in the absence of the signal matching circuit 50, the enable and dimming signal input D1 of the dimming control circuit 40 is driven by a high level, and when the enable and dimming signal input D1 receives the high level, the backlight light bar 70 is controlled to be turned on. When the electronic device is started, the master control circuit is started to generate a pulse of one millisecond level, the pulse can drive the dimming control circuit 40 to light the backlight lamp strip, and because the pulse duration is very short, when the master control circuit 60 outputs a low level, the enabling and dimming signal input end D1 of the dimming control circuit 40 receives the low level two to control the backlight lamp strip 70 to be turned off, so that in a short time of starting, human eyes can observe that the display screen is shiny. The first resistor R1, the second resistor R2 and the third resistor R3 jointly form the signal matching circuit 50, when the display screen is started, the main control circuit 60 configures the low level of the PWM signal output end F1 of the main control circuit through software to be effective, and the level of the short-time pulse output by the PWM signal output end F1 of the main control circuit 60 is pulled down through the first resistor R1 and the third resistor R3, so that the enabling of the dimming control circuit and the dimming signal input end D1 receive the low level, the backlight lamp bar 70 cannot be lightened, and the phenomenon of flickering cannot occur on the display screen.
Optionally, on the basis of the above embodiment, with continued reference to fig. 2, the signal matching circuit 50 further includes a first capacitor C1;
a first terminal of the first capacitor C1 is electrically connected to the enable and dimming signal input terminal D1 of the dimming control circuit 40, and a second terminal of the first capacitor C1 is grounded.
Specifically, the main control circuit 60 is electrically connected to the dimming control circuit 40 through a wire or a signal line, when the length of the wire or the signal line is too long, parasitic parameters on the wire may interfere with transmission of the signal, and the signal can be filtered by adding the first capacitor C1, so that the anti-interference capability of the signal matching circuit 50 is increased.
Optionally, on the basis of the foregoing embodiment, with reference to fig. 2, the signal matching circuit 50 further includes a first diode D1 and a fourth resistor R4, and the main control circuit 60 further includes an enable signal output terminal F2;
an anode of the first diode D1 is electrically connected to an enable and dimming signal input terminal D1 of the dimming control circuit 40, and a cathode of the first diode D1 is electrically connected to an enable signal output terminal F2 of the main control circuit 60;
a first terminal of the fourth resistor R4 is electrically connected to the cathode of the first diode D1, and a second terminal of the fourth resistor R4 is grounded.
Specifically, the enable signal output terminal F2 of the main control circuit 60 outputs a high level all the time, the backlight light bar 70 is lighted due to the enable and dimming signal input terminal D1 of the dimming control circuit 40 receiving the high level, when the PWM signal output terminal F1 of the main control circuit 60 outputs a low level, the dimming control circuit 40 should not light the backlight light bar 70, but the backlight light bar is lighted due to the enable signal output terminal F2 of the main control circuit 60 outputting the high level to the enable and dimming signal input terminal D1 of the dimming control circuit 40. Therefore, in order to solve the contradiction, the fourth resistor R4 is added to pull the high level output by the enable signal output terminal F2 of the main control circuit 60 low, and then the enable signal is cut off by the first diode D1, that is, when the PWM dimming signal output by the PWM signal output terminal F1 of the main control circuit 60 is low, the enable signal output terminal F2 of the main control circuit 60 is shielded by the first diode D1 and the fourth resistor R4, so that the enable and dimming signal input terminals of the dimming control circuit 40 receive the low level, and the backlight light bar 70 is not lighted.
Optionally, fig. 3 is a schematic structural diagram of another module backlight control circuit provided in an embodiment of the present invention, and referring to fig. 3, on the basis of the above embodiment, the dimming control circuit 40 includes a current control chip U1, the current control chip U1 includes a power supply terminal 1, an enable and dimming signal input terminal 8, a voltage output terminal 5 and a constant current driving terminal 2, and the rectifying and filtering circuit 20 further includes a second output terminal B3;
a power supply end 1 of the current control chip U1 is electrically connected with a second output end B3 of the rectifying and filtering circuit 20, an enable and dimming signal input end 8 of the current control chip U1 is electrically connected with a first end of a first resistor R1, a constant current driving end 2 of the current control chip U1 is electrically connected with a control end C3 of the voltage conversion circuit 30, and a voltage output end 5 of the current control chip U1 is electrically connected with a second pole G2 of the backlight lamp strip 70;
the enable and dimming signal inputs 8 of the current control chip U1 multiplex the enable signal and the dimming signal.
Specifically, the current control chip U1 may be a constant current control chip for realizing current control of the backlight light bar 70, and in the process of turning on the backlight light bar 70, when the power supply system of the current control chip U1 is established, the turning on and dimming functions of the current control chip U1 are realized through the enabling and dimming signal input terminal 8. The power supply system of the current control chip U1 is established by the rectifying-filtering circuit 20, and the rectifying-filtering circuit 20 converts the low-voltage alternating current output by the transformer 10 into the direct current voltage required by the power supply terminal 1 of the current control chip U1. The enable and dimming signal input end 8 of the current control chip U1 is a multiplexing pin, and can be used for inputting an enable signal and a PWM dimming signal, and when the enable and dimming signal input end 8 of the current control chip U1 receives a high level, the current control chip U1 controls the backlight light bar to be turned on. When the backlight lamp is turned on, the enable signal output terminal F2 of the main control circuit 60 outputs a high level, the PWM signal output terminal F1 outputs a short pulse to enable the current control chip U1 to operate, so as to light the backlight lamp bar, and a phenomenon of screen flashing occurs, and since the enable of the current control chip U1 and the dimming signal input terminal 8 are multiplexing pins, when the PWM dimming signal output by the PWM signal output terminal F1 of the main control circuit 60 is a low level, the enable signal output terminal F2 of the main control circuit 60 is shielded by the first diode D1 and the fourth resistor R4, so that the enable and dimming signal input terminals of the dimming control circuit 40 receive a low level, and the backlight lamp bar 70 is not lit. And the enabling signal input end 8 of the current control chip U1 and the dimming signal input end can omit the function of the enabling signal output end F2 when the main control circuit 60 defines the I/O port of the main control circuit through multiplexing the enabling signal and the dimming signal, thereby simplifying the function definition of the main control circuit 60 and being beneficial to reducing the development cost of the system.
Optionally, on the basis of the foregoing embodiment, with continued reference to fig. 3, the dimming control circuit 40 further includes a driving circuit 41, and the driving circuit 41 includes a sixth resistor R6, a seventh resistor R7, a third capacitor C3, and a fourth capacitor C4; the current control chip U1 further includes a current control terminal 7 and a current compensation terminal 6;
a first end of the sixth resistor R6 is electrically connected with the current control end 7 of the current control chip U1, and a second end of the sixth resistor R6 is grounded;
the first end of the seventh resistor R7 is electrically connected with the current compensation end 6 of the current control chip U1, the second end of the seventh resistor R7 is grounded through the third capacitor C3, and the current compensation end 7 of the current control chip U1 is connected through the third capacitor C3
The fourth capacitor C4 is connected to ground.
Specifically, in the working process of the backlight control circuit of the module, the output current of the current control chip U1 can be controlled and compensated through the driving circuit 41, so as to drive and control the backlight light bar 70, and improve the working stability of the current control chip U1.
Optionally, fig. 4 is a schematic structural diagram of another backlight control circuit of a module according to an embodiment of the present invention, and referring to fig. 4, the voltage conversion circuit 30 includes a fifth resistor R5, a first switch Q1, a second diode D2, a first inductor L1, and a second capacitor C2;
a first end of the fifth resistor R5 is electrically connected with the constant current driving end 2 of the current control chip U1, a second end of the fifth resistor R5 is electrically connected with a first pole of the first switch tube Q1, a second pole of the first switch tube Q1 is electrically connected with an anode of the second diode D2, and a third pole of the first switch tube Q1 is grounded;
the cathode of the second diode D2 is electrically connected to the first pole of the backlight light bar 70, and the second pole of the backlight light bar 70 is electrically connected to the voltage output terminal 5 of the current control chip U1;
a first end of the first inductor L1 is electrically connected to the first output end B2 of the rectifying-smoothing circuit 20, and a second end of the first inductor L1 is electrically connected to the second pole of the first switch Q1;
a first end of the second capacitor C2 is electrically connected to the first pole of the backlight light bar 70, and a second end of the second capacitor C2 is grounded.
Specifically, the voltage conversion circuit 30 is configured to boost the first dc voltage output from the first output terminal B2 of the rectifying and filtering circuit 20 to the third dc voltage VOUT3 required by the backlight light bar 70 to light the backlight light bar 70, when the main control circuit 60 completes system configuration, the enable signal output terminal F2 of the main control circuit 60 is shielded by the first diode D1 and the fourth resistor R4 (the enable signal output terminal F2 of the main control circuit 60 may be omitted by optimization), when the backlight light bar is turned on, the main control circuit 60 configures the low level of the PWM signal output terminal F1 thereof to be active by software, and pulls the level of the short-time pulse output from the PWM signal output terminal F1 of the main control circuit 60 to be low by the first resistor R1 and the third resistor R3, so that the enable and dimming signal input terminal D1 of the dimming control circuit receives the low level, and thus the backlight light bar 70 will not light when the dimming signal enters the signal matching circuit 50, the PWM signal output terminal F1 of the main control circuit controls the first dc voltage output terminal Q switch to be low level when the PWM signal output terminal Q switch 869 of the backlight light bar 70 is turned on, the first diode R869, the rectifying and the second dc voltage switch R8672 is switched to turn off, thereby preventing the first dc voltage switch 3614 from receiving the first dc voltage as the rectified dc voltage v _ on signal output voltage when the first dc voltage v _ rectified voltage v _ F3628, the rectified voltage v _ F _ rectified voltage reaches the first diode R _ F _ R _ rectified voltage, the first diode R _ R.
Optionally, fig. 5 is a schematic structural diagram of another module backlight control circuit provided in an embodiment of the present invention, and referring to fig. 5, an output terminal a2 of the transformer 10 includes a first output terminal a21 and a second output terminal a22, and the rectifying and filtering circuit 20 includes a first rectifying and filtering circuit 21 and a second rectifying and filtering circuit 22;
the first rectifying and filtering circuit 21 comprises a third diode D3 and a fifth capacitor C5;
an anode of the third diode D3 is electrically connected to the first output terminal a21 of the transformer 10, a cathode of the third diode D3 is electrically connected to the first terminal of the first inductor L1, a first terminal of the fifth capacitor C5 is electrically connected to a cathode of the third diode D3, and a second terminal of the fifth capacitor C5 is grounded;
the second rectifying and filtering circuit 22 comprises a fourth diode D4 and a sixth capacitor C6;
an anode of the fourth diode D4 is electrically connected to the second output terminal a22 of the transformer 10, a cathode of the fourth diode D4 is electrically connected to the power supply terminal 1 of the current control chip U1, a first terminal of the sixth capacitor C6 is electrically connected to a cathode of the fourth diode D4, and a second terminal of the sixth capacitor C6 is grounded.
Specifically, the first rectifying and filtering circuit 21 is configured to convert the low-voltage ac output by the first output terminal a21 of the transformer 10 into a first dc voltage VOUT1, and the voltage converting circuit 30 converts the first dc voltage VOUT1 into a third dc voltage VOUT3 required by the backlight light bar 70 to light the backlight light bar 70. The second rectifying-smoothing circuit 22 is configured to convert the low-voltage ac voltage output from the second output terminal a22 of the transformer 10 into a second dc voltage VOUT2, so as to provide a power voltage for the current control chip U1.
Optionally, fig. 6 is a schematic structural diagram of another module backlight control circuit provided in an embodiment of the present invention, and referring to fig. 6, on the basis of the above embodiment, the module backlight control circuit further includes a DC/DC circuit 80, and the main control circuit 60 further includes a power supply terminal F3;
an input end H1 of the DC/DC circuit 80 is electrically connected with a second output end B3 of the rectifying and filtering circuit 20, and an output end H2 of the DC/DC circuit 80 is electrically connected with a power supply end F3 of the main control circuit 60.
The DC/DC circuit 80 is configured to convert the second DC voltage VOUT2 output from the second output terminal B3 of the rectifying and filtering circuit 20 into a voltage required by the main control circuit 60, so as to provide a power voltage for the main control circuit 60.
With continued reference to fig. 6, the specific working principle of the backlight control circuit of the module is as follows:
the input end a1 of the transformer 10 can input 100-240V ac power and convert the input ac voltage into low-voltage ac power, the rectifying-smoothing circuit 20 rectifies and smoothes the low-voltage ac power input at the input end B1, and outputs a first dc voltage VOUT1 and a second dc voltage VOUT2 through the first rectifying-smoothing circuit 21 and the second rectifying-smoothing circuit 22, respectively, and the second dc voltage VOUT2 provides a power supply voltage for the current control chip U1 and the main control circuit 60. The main control circuit 60 may be a main control chip, and the main control chip respectively configures its I/O ports as an enable signal output terminal F2 and a PWM signal output terminal F1 after being powered by the DC/DC circuit 80, and configures the PWM signal output terminal to be active at a low level within a short time after being powered on, for example, 2 milliseconds. After the configuration is completed, the main control circuit 60 outputs an enable signal and a PWM dimming signal respectively, the signal matching circuit 50 pulls down the level of the short-time pulse output by the PWM signal output terminal F1 of the main control circuit 60 through the first resistor R1 and the third resistor R3 within 2 milliseconds, so that the enable and dimming signal input terminal D1 of the dimming control circuit receives the low level, the backlight lamp bar 70 cannot be lighted, and the display screen cannot flash. After 2 milliseconds, the high level of the PWM dimming signal enters the enable and dimming signal input terminal of the current control chip U1, and the PWM dimming signal at this time has no short-time pulse, but has a fixed frequency at which human eyes cannot recognize the change of the display screen.
When the PWM dimming signal sent by the main control circuit 60 is at a high level in a dimming cycle, the enable signal sent by the main control circuit is also at a high level, at this time, the current control chip U1 is only controlled by the PWM dimming signal, the current control chip U1 drives the voltage conversion circuit to convert the first dc voltage VOUT1 into the third dc voltage VOUT3, so as to light the backlight light bar 70, the magnitude of the current output from the current control chip U1 to the backlight light bar 70 can be changed by changing the duty ratio of the PWM dimming signal, and further, the backlight light bar 70 can be dimmed. When the PWM dimming signal from the main control circuit 60 is at a low level in a dimming cycle, since the enable signal from the main control circuit 60 is also at a high level, the first diode D1 and the fourth resistor R4 in the signal matching circuit 50 shield the enable signal output terminal of the main control circuit 60, and only receive the low level of the PWM dimming signal. After the current control chip U1 receives the low level PWM dimming signal, it stops working and the backlight light bar 70 goes out.
In particular, the enable signal output terminal of the main control chip in the main control circuit 60 can be omitted, so that the function definition of the main control chip can be simplified, and the cost of the main control chip can be reduced.
The embodiment of the utility model provides a technical scheme, PWM dimming signal that combines master control circuit's PWM signal output part through signal matching circuit matches dimming control circuit's the messenger and the signal of dimming signal input part, adopt two IO mouths and dimming control circuit to use an IO mouth to communicate through master control circuit, realize dimming control circuit's the messenger and the function of dimming signal simultaneous control, through signal matching circuit realization master control circuit's PWM signal output part and messenger's end and dimming control circuit's messenger and the voltage matching between the dimming signal input part promptly. Therefore, compared with the prior art, the embodiment of the utility model provides a under the condition of the enable signal input part who omits dimming control circuit, through dimming control circuit and master control circuit's matching, the problem of the start splash screen has been solved, and under the reduce system cost, has improved module backlight control circuit's stability.
The utility model also provides a TV set, this TV set includes the utility model discloses the module control circuit that is shaded that arbitrary embodiment provides, consequently the utility model provides a TV set also has the beneficial effect that describes in the above-mentioned embodiment, no longer gives unnecessary details here.
It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.
Claims (10)
1. A kind of die set backlight control circuit, characterized by, comprising: the device comprises a transformer, a rectifying and filtering circuit, a dimming control circuit, a signal matching circuit, a voltage conversion circuit and a main control circuit;
the transformer comprises an input end and an output end, and the input end of the transformer is connected with an alternating voltage;
the rectifier filter circuit comprises an input end and a first output end, and the input end of the rectifier filter circuit is electrically connected with the output end of the transformer;
the voltage conversion circuit comprises an input end, an output end and a control end, the input end of the voltage conversion circuit is electrically connected with the first output end of the rectification filter circuit, the output end of the voltage conversion circuit is electrically connected with the first electrode of the backlight lamp bar, and the voltage conversion circuit is used for converting the voltage output by the first output end of the rectification filter circuit into the voltage matched with the backlight lamp bar;
the dimming control circuit comprises an enabling and dimming signal input end, an output end and a driving end, the enabling and dimming signal input end of the dimming control circuit is connected with the PWM signal output end of the main control circuit through the signal matching circuit, the output end of the dimming control circuit is connected with the second pole of the backlight lamp strip, the driving end of the dimming control circuit is connected with the control end of the voltage conversion circuit, and the signal matching circuit is used for matching the enabling and dimming signal input end of the dimming control circuit and the voltage of the PWM signal output end of the main control circuit.
2. The backlight control circuit according to claim 1, wherein the signal matching circuit comprises a first resistor, a second resistor, and a third resistor;
the first end of the first resistor is electrically connected with the enabling and dimming signal input end of the dimming control circuit, the second end of the first resistor is grounded, the first end of the second resistor is electrically connected with the first end of the first resistor, the second end of the second resistor is electrically connected with the PWM signal output end of the main control circuit, the first end of the third resistor is electrically connected with the second end of the second resistor, and the second end of the third resistor is grounded.
3. The modular backlight control circuit of claim 2, wherein the signal matching circuit further comprises a first capacitor;
the first end of the first capacitor is electrically connected with the enabling and dimming signal input end of the dimming control circuit, and the second end of the first capacitor is grounded.
4. The modular backlight control circuit of claim 3, wherein the signal matching circuit further comprises a first diode and a fourth resistor, the master control circuit further comprises an enable signal output terminal;
the anode of the first diode is electrically connected with the enabling and dimming signal input end of the dimming control circuit, and the cathode of the first diode is electrically connected with the enabling signal output end of the main control circuit;
the first end of the fourth resistor is electrically connected with the cathode of the first diode, and the second end of the fourth resistor is grounded.
5. The modular backlight control circuit of claim 2, wherein the dimming control circuit comprises a current control chip, the current control chip comprises a power supply terminal, an enable and dimming signal input terminal, a voltage output terminal and a constant current drive terminal, and the rectifying and filtering circuit further comprises a second output terminal;
the power supply end of the current control chip is electrically connected with the second output end of the rectification filter circuit, the enabling and dimming signal input ends of the current control chip are electrically connected with the first end of the first resistor, the constant current driving end of the current control chip is electrically connected with the control end of the voltage conversion circuit, and the voltage output end of the current control chip is electrically connected with the second pole of the backlight lamp bar;
and the enable and dimming signal input ends of the current control chip multiplex an enable signal and a dimming signal.
6. The backlight control circuit according to claim 5, wherein the voltage converting circuit comprises a fifth resistor, a first switch transistor, a second diode, a first inductor and a second capacitor;
a first end of the fifth resistor is electrically connected with a constant-current driving end of the current control chip, a second end of the fifth resistor is electrically connected with a first pole of the first switch tube, a second pole of the first switch tube is electrically connected with an anode of the second diode, and a third pole of the first switch tube is grounded;
the cathode of the second diode is electrically connected with the first pole of the backlight lamp bar, and the second pole of the backlight lamp bar is electrically connected with the voltage output end of the current control chip;
the first end of the first inductor is electrically connected with the first output end of the rectifying and filtering circuit, and the second end of the first inductor is electrically connected with the second pole of the first switch tube;
the first end of the second capacitor is electrically connected with the first pole of the backlight lamp bar, and the second end of the second capacitor is grounded.
7. The modular backlight control circuit of claim 5, wherein the dimming control circuit further comprises a driving circuit, the driving circuit comprising a sixth resistor, a seventh resistor, a third capacitor and a fourth capacitor; the current control chip also comprises a current control end and a current compensation end;
the first end of the sixth resistor is electrically connected with the current control end of the current control chip, and the second end of the sixth resistor is grounded;
the first end of the seventh resistor is electrically connected with the current compensation end of the current control chip, the second end of the seventh resistor is grounded through the third capacitor, and the current compensation end of the current control chip is grounded through the fourth capacitor.
8. The modular backlight control circuit of claim 6, wherein the output terminal of the transformer comprises a first output terminal and a second output terminal, and the rectifying filter circuit comprises a first rectifying filter circuit and a second rectifying filter circuit;
the first rectifying and filtering circuit comprises a third diode and a fifth capacitor;
the anode of the third diode is electrically connected with the first output end of the transformer, the cathode of the third diode is electrically connected with the first end of the first inductor, the first end of the fifth capacitor is electrically connected with the cathode of the third diode, and the second end of the fifth capacitor is grounded;
the second rectifying and filtering circuit comprises a fourth diode and a sixth capacitor;
an anode of the fourth diode is electrically connected with the second output end of the transformer, a cathode of the fourth diode is electrically connected with a power supply end of the current control chip, a first end of the sixth capacitor is electrically connected with a cathode of the fourth diode, and a second end of the sixth capacitor is grounded.
9. The modular backlight control circuit of claim 5, further comprising a DC/DC circuit, the master control circuit further comprising a power supply terminal;
the input end of the DC/DC circuit is electrically connected with the second output end of the rectification filter circuit, and the output end of the DC/DC circuit is electrically connected with the power supply end of the main control circuit.
10. A television set, characterized in that it comprises a modular backlight control circuit according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922095235.4U CN211062443U (en) | 2019-11-28 | 2019-11-28 | Module backlight control circuit and television |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922095235.4U CN211062443U (en) | 2019-11-28 | 2019-11-28 | Module backlight control circuit and television |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211062443U true CN211062443U (en) | 2020-07-21 |
Family
ID=71593704
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201922095235.4U Active CN211062443U (en) | 2019-11-28 | 2019-11-28 | Module backlight control circuit and television |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN211062443U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112216245A (en) * | 2020-10-09 | 2021-01-12 | 深圳创维－Rgb电子有限公司 | Adjusting circuit and method for module backlight lamp bar of television |
-
2019
- 2019-11-28 CN CN201922095235.4U patent/CN211062443U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112216245A (en) * | 2020-10-09 | 2021-01-12 | 深圳创维－Rgb电子有限公司 | Adjusting circuit and method for module backlight lamp bar of television |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108667289B (en) | Power supply device and power supply method | |
| CN108231014B (en) | Regional dimming constant current control circuit, driving power supply and television | |
| CN103813595A (en) | Efficient power source capable of supplying electricity in constant voltage and constant current alternation mode | |
| CN110536506A (en) | The quick-fried lightning road of LED stroboscopic | |
| CN100530921C (en) | Flyback pulse width modulation device with power-saving mode | |
| CN211062443U (en) | Module backlight control circuit and television | |
| CN205160851U (en) | Two unification powers | |
| CN211352536U (en) | Constant current load circuit, backlight adjusting circuit, driving board card and electronic equipment | |
| CN118713270A (en) | Automatic transfer switch circuit and electronic equipment thereof | |
| CN215581794U (en) | Remote dimming power supply | |
| CN106910475B (en) | New type liquid crystal television back light driving circuit | |
| CN111371094B (en) | Double-power-supply system and television | |
| CN202121830U (en) | Buck-boost constant-current power supply for LED lamps | |
| CN215581795U (en) | Remote sectional timing light-regulating power supply | |
| CN210016663U (en) | Slow-start stroboscopic-removing jitter control circuit and lamp | |
| CN214381516U (en) | Prevent dodging wall switch circuit that single fire was got electricity | |
| CN213126532U (en) | PWM-controlled stroboflash-free dimming and color-adjusting driving circuit and driving power supply | |
| CN109922585B (en) | Light control circuit | |
| CN118076995A (en) | Display device and display control method | |
| WO2021047387A1 (en) | Buck topological circuit for power supply | |
| CN107567136B (en) | LED dimming and color adjustment circuit and LED dimming and color adjustment device | |
| CN212517041U (en) | Switching circuit for ammeter | |
| CN115038213B (en) | A non-flickering, ultra-quiet, high-power LED lamp switching power supply circuit and soft-start method thereof | |
| CN112543532B (en) | Dimming control circuit and device thereof | |
| CN220421641U (en) | Boost circuit and power module applying same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |