CN110994967A - Reverse switching circuit, television power supply and television - Google Patents
Reverse switching circuit, television power supply and television Download PDFInfo
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- CN110994967A CN110994967A CN201911362665.6A CN201911362665A CN110994967A CN 110994967 A CN110994967 A CN 110994967A CN 201911362665 A CN201911362665 A CN 201911362665A CN 110994967 A CN110994967 A CN 110994967A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
- H02M1/322—Means for rapidly discharging a capacitor of the converter for protecting electrical components or for preventing electrical shock
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention discloses a reverse switch circuit, a television power supply and a television, wherein the reverse switch circuit is connected with an AC input filter circuit, a PFC circuit and an LLC circuit and comprises a sampling circuit, a voltage-stabilizing filter module and a switch unit; when the alternating current input is powered on, the AC input filtering module filters the input alternating current and outputs the filtered alternating current to the sampling circuit, the sampling circuit samples the filtered alternating current and outputs a third sampling voltage to the voltage stabilizing filtering module, the voltage stabilizing filtering module filters and stabilizes the third sampling voltage and outputs direct current voltage to the switch unit, and finally the switch unit is conducted to clamp the voltage of the LLC control chip and the PFC control chip to be normal working voltage; when the alternating current input is powered off, the switching unit is reversely started to rapidly discharge the chip input voltages of the LLC control chip and the PFC control chip to the ground, so that the rapid oscillation stop of the chip is realized, and the television can be rapidly restarted when the alternating current input of the television power supply is powered off and is rapidly powered on again.
Description
Technical Field
The invention relates to the field of television power supplies, in particular to a reverse switching circuit, a television power supply and a television.
Background
With the development of society, the development of science and technology also pushes televisions to the intelligent frontier, and smart televisions are provided with high-performance chips and developed intelligent operating systems, so that the smart televisions become audio terminal application platforms integrating functions of home audio and video, entertainment, learning, life assistance and the like. The power supply is used as the energy supply end of the television, and the stable operation of the power supply is a precondition for ensuring that all functions of the television are normally in front of the user.
In the existing television power supply, if the AC input is quickly powered on after being quickly powered off, the PFC electrolytic capacitor in the PFC circuit is not completely discharged, but the voltage is reduced to cause the television mainboard to enter an undervoltage locking state, and the television cannot be quickly restarted after the AC is powered on.
Thus, the prior art has yet to be improved and enhanced.
Disclosure of Invention
In view of the defects of the prior art, the invention aims to provide a reverse switching circuit, a television power supply and a television, wherein the switching unit is reversely started to rapidly discharge the input voltages of an LLC control chip and a PFC control chip to the ground when the alternating current input is powered off, so that the rapid response can be realized when the power is rapidly powered off and on.
In order to achieve the purpose, the invention adopts the following technical scheme:
a reverse switching circuit connected to an AC input filter circuit, a PFC circuit and an LLC circuit, said reverse switching circuit comprising: the sampling circuit, the voltage stabilizing and filtering module and the switch unit; when the alternating current input is powered on, the AC input filtering module filters the input alternating current and outputs the filtered alternating current to the sampling circuit, the sampling circuit samples the filtered alternating current and outputs a third sampling voltage to the voltage stabilizing filtering module, the voltage stabilizing filtering module filters and stabilizes the third sampling voltage and outputs direct current voltage to the switch unit, and finally the switch unit is conducted to clamp the voltage of the LLC control chip and the PFC control chip to be normal working voltage; when the alternating current input is powered off, the switching unit is reversely started to rapidly discharge the chip input voltages of the LLC control chip and the PFC control chip to the ground.
The sampling circuit comprises a first sampling unit, a second sampling unit and a third sampling unit, the first sampling unit samples the voltage of the zero line and outputs a first sampling voltage to the third sampling unit, the second sampling unit outputs the voltage of the live wire and outputs a second sampling voltage to the third sampling unit, the third sampling unit samples the first sampling voltage or the second sampling voltage to perform secondary sampling to obtain a third sampling voltage, and then the third sampling voltage is output to the voltage stabilization filtering module.
The first sampling unit comprises a first sampling resistor and a second sampling resistor, one end of the first sampling resistor is connected with the output end zero line of the AC input filtering module, the other end of the first sampling resistor is connected with one end of the second sampling resistor, and the other end of the second sampling resistor is connected with the second sampling power supply and the third sampling unit.
The second sampling unit comprises a third sampling resistor and a fourth sampling resistor, one end of the third sampling resistor is connected with an output end live wire of the AC input filtering module, the other end of the third sampling resistor is connected with one end of the fourth sampling resistor, and the other end of the fourth sampling resistor is connected with one end of the second sampling resistor and the third sampling unit.
The third sampling unit comprises a fifth sampling resistor, a sixth sampling resistor and a seventh sampling resistor, one end of the fifth sampling resistor is connected with the other end of the second sampling resistor and the other end of the fourth sampling resistor, the other end of the fifth sampling resistor is connected with one end of the sixth sampling resistor, the other end of the sixth sampling resistor is connected with one end of the seventh sampling resistor and the voltage-stabilizing filtering module, and the other end of the seventh sampling resistor is connected with the voltage-stabilizing filtering module and grounded.
The voltage stabilizing and filtering module comprises a first filtering capacitor and a first voltage stabilizing diode, one end of the first filtering capacitor is connected with the other end of the sixth sampling resistor, one end of the seventh sampling resistor, the output end of the first voltage stabilizing diode and the switch unit, and the other end of the first filtering capacitor is connected with the input end of the first voltage stabilizing diode and the switch unit and is connected with the ground.
The switch unit comprises a first MOS tube, a second MOS tube, a clamping resistor, a discharge resistor and a first capacitor, wherein the grid electrode of the first MOS tube is connected with the output end of the first voltage stabilizing diode, one end of the first filter capacitor, the other end of the sixth sampling resistor and one end of the seventh sampling resistor, the source electrode of the first MOS tube is grounded, the drain electrode of the first MOS tube is connected with the grid electrode of the second MOS tube, one end of the first capacitor and one end of the clamping resistor, the source electrode of the second MOS tube and the other end of the first capacitor are grounded, the drain electrode of the second MOS tube is connected with one end of the discharge resistor, and the other end of the discharge resistor is connected with a PFC circuit and an LLC circuit at the other end of the clamping resistor.
A television power supply comprises a power supply board connected with a television main board and an LED display screen, wherein an AC input filtering module, a first rectifying circuit, a PFC circuit, an LLC circuit, a secondary rectifying circuit and the reverse switch circuit are arranged on the power supply board; the AC input filter module is connected with an input plug, AC is accessed by the input plug and transmitted to the AC input filter module, the AC is input and filtered by the AC input filter module and is output to the first rectifying circuit and the reverse switch circuit, the AC is rectified by the first rectifying circuit and is output to the PFC circuit, the power of the PFC circuit is corrected and is output to the LLC circuit, the LLC circuit is used for voltage output control and is output to the secondary rectifying circuit and the reverse switch circuit, the reverse switch circuit is used for chip input voltage clamping on the LLC circuit and the PFC circuit after receiving the AC voltage of the AC input filter module, and the secondary rectifying circuit is used for rectifying after receiving the output voltage of the LLC circuit and supplying power to the mainboard and the LED display screen; and when the AC input filter module is powered off, the reverse switch circuit is reversely started to rapidly discharge the chip input voltages of the LLC control chip and the PFC control chip to the ground.
The LLC circuit comprises a third MOS tube, a fourth MOS tube, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a first electrolytic capacitor, a second electrolytic capacitor, an eighth resistor, a ninth resistor, a first transformer, a first resonant capacitor and an LLC control chip;
the other end of the clamping resistor and the other end of the discharge resistor are connected with an SUPIC pin of an LLC control chip, one end of a first electrolytic capacitor, the output end of a first diode and a PFC circuit, the input end of the first diode is connected with one end of a second electrolytic capacitor, the output end of a second diode and the output end of a third diode, the other end of the first electrolytic capacitor and the other end of the second electrolytic capacitor are grounded, the input end of the second diode is connected with a fifteenth pin of a first transformer, the input end of the third diode is connected with a seventeenth pin of the first transformer, a fifth pin of the first transformer is connected with a source electrode of a third MOS (metal oxide semiconductor) transistor and a drain electrode of a fourth MOS (metal oxide semiconductor) transistor, a sixth pin of the first transformer is connected with one end of a first resonant capacitor, the other end of the first resonant capacitor is grounded, a ninth pin, a pin of the first transformer, and an output end of a, The tenth pin, the eleventh pin, the twelfth pin, the thirteenth pin and the fourteenth pin are all connected with the secondary rectifying circuit, the seventh pin, the eighth pin and the sixteenth pin of the first transformer are all grounded, the drain electrode of the third MOS tube is connected with the PFC circuit, the grid electrode of the third MOS tube is connected with the input end of the fourth diode and one end of the eighth resistor, the output end of the fourth diode and the other end of the eighth resistor are both connected with one end of a tenth resistor, the GATEHS pin of the LLC control chip at the other end of the tenth resistor is connected, the source of the fourth MOS transistor is grounded, the grid electrode of the fourth MOS tube is connected with the input end of the fifth diode and one end of a ninth resistor, the output end of the fifth diode and the other end of the ninth resistor are both connected with one end of an eleventh resistor, and the other end of the eleventh resistor is connected with a GATELS pin of the LLC control chip.
A television comprises a television mainboard and an LED display screen, and further comprises the television power supply, wherein the television power supply is connected with the television mainboard and the LED display screen.
Compared with the prior art, the reverse switch circuit, the television power supply and the television provided by the invention are connected with the AC input filter circuit, the PFC circuit and the LLC circuit, and the reverse switch circuit comprises a sampling circuit, a voltage-stabilizing filter module and a switch unit; when the alternating current input is powered on, the AC input filtering module filters the input alternating current and outputs the filtered alternating current to the sampling circuit, the sampling circuit samples the filtered alternating current and outputs a third sampling voltage to the voltage stabilizing filtering module, the voltage stabilizing filtering module filters and stabilizes the third sampling voltage and outputs direct current voltage to the switch unit, and finally the switch unit is conducted to clamp the voltage of the LLC control chip and the PFC control chip to be normal working voltage; when the alternating current input is powered off, the switching unit is reversely started to rapidly discharge the chip input voltages of the LLC control chip and the PFC control chip to the ground, so that the rapid oscillation stop of the chip is realized, and the television can be rapidly restarted when the alternating current input of the television power supply is powered off and is rapidly powered on again.
Drawings
FIG. 1 is a functional block diagram of the structure of a reverse switching circuit provided in the present invention;
FIG. 2 is a circuit diagram of a reverse switching circuit provided in the present invention;
FIG. 3 is a functional block diagram of the structure of a television power supply provided by the present invention;
fig. 4 is a circuit diagram of an LLC control circuit provided by the present invention.
Detailed Description
In view of the problem that the rapid power-on cannot be restarted immediately after the alternating current input is powered off in the prior art, the invention provides the reverse switch circuit, the television power supply and the television.
The embodiments of the present invention are intended to explain technical concepts of the present invention, technical problems to be solved, technical features constituting technical solutions, and technical effects to be brought about in more detail. The embodiments are explained below, but the scope of the present invention is not limited thereto. Further, the technical features of the embodiments described below may be combined with each other as long as they do not conflict with each other.
In the prior art, when the alternating current input of the television power supply is powered off, the electric quantity stored in a PFC electrolytic capacitor in a PFC circuit cannot be discharged quickly, so that an LLC control chip of an LLC circuit can be supplied with power and continues to work; therefore, the transformer can still transmit energy to the secondary side, and the voltage of 12V is continuously output, so that the main board of the television continues to work. The 12V voltage is slowly reduced along with the slow release of the electric quantity stored by the PFC electrolytic capacitor, when the voltage is reduced to 6-7V, the DC-DC of the main board enters an under-voltage locking state, and the main board is restarted until the input voltage is smaller than the specification value of the DC-DC control chip, namely, the main board is fully discharged; if the alternating current input is powered on again in the locked state of the main board, the phenomenon that the television cannot be restarted normally occurs because the main board is locked.
Based on the above problem, referring to fig. 1, the present invention provides a reverse switch circuit 600, wherein the reverse switch circuit 600 is connected from the output terminal of the AC input filter circuit 100 and the chip input voltage SUPIC input terminals of the LLC circuit 400 and the PFC circuit 300 on the basis of the existing television power supply, so as to discharge the input voltages of the LLC control chip U1 and the PFC control chip U2. Wherein the reverse switching circuit 600 includes: the sampling circuit, the voltage-stabilizing filtering module and the switch unit are connected in sequence, and the AC input filtering circuit 100, the sampling circuit, the voltage-stabilizing filtering module, the switch unit and the LLC circuit 400 are connected in sequence. When the alternating current input is powered on, the AC input filter circuit 100 filters the input alternating current and outputs the filtered alternating current to the sampling circuit, the sampling circuit samples the filtered alternating current and outputs a third sampling voltage to the voltage stabilizing filter module, the voltage stabilizing filter module filters and stabilizes the third sampling voltage, the direct current voltage is output and stabilized at the input voltage value of the control IC and is output to the switch unit, and finally, the switch unit clamps the voltages of the LLC control chip U1 and the PFC control chip U2 to be normal working voltages; when the alternating current input is powered off, the switching unit is reversely started to quickly discharge the chip input voltage SUPIC of the LLC control chip U1 and the PFC control chip U2 to the ground. According to the invention, the switch unit is reversely started when the alternating current input is powered off, so that the input voltages of the LLC control chip U1 and the PFC control chip U2 are quickly discharged to the ground, and the quick response can be realized when the alternating current input is powered off and on.
Specifically, referring to fig. 2, the sampling circuit includes a first sampling unit, a second sampling unit and a third sampling unit, the first sampling unit samples the voltage of the zero line and outputs a first sampling voltage to the third sampling unit, the second sampling unit outputs a second sampling voltage to the third sampling unit by using the voltage of the live line, the third sampling unit samples the first sampling voltage or the second sampling voltage and performs secondary sampling to obtain a third sampling voltage, and then the third sampling voltage is output to the voltage stabilizing and filtering module.
In this embodiment, the first sampling unit is responsible for sampling the voltage of the zero line at the output end of the AC input filter circuit 100, the second sampling unit is responsible for sampling the voltage of the live line at the output end of the AC input filter circuit 100, and the third sampling unit is responsible for performing secondary sampling on the voltage of the first sampling unit or the second sampling unit to obtain a third sampling voltage and output the third sampling voltage to the voltage stabilizing filter module and the switch unit.
Specifically, referring to fig. 2, in the reverse switch circuit 600 of the present invention, the first sampling unit includes a first sampling resistor R1 and a second sampling resistor R2, one end of the first sampling resistor R1 is connected to a zero line of an output end of the AC input filter circuit 100, the other end of the first sampling resistor R1 is connected to one end of the second sampling resistor R2, and the other end of the second sampling resistor R2 is connected to the second sampling power supply and the third sampling unit. The second sampling unit comprises a third sampling resistor R3 and a fourth sampling resistor R4, one end of the third sampling resistor R3 is connected with the output end live wire of the AC input filter circuit 100, the other end of the third sampling resistor R3 is connected with one end of the fourth sampling resistor R4, and the other end of the fourth sampling resistor R4 is connected with one end of the second sampling resistor R2 and the third sampling unit. The third sampling unit comprises a fifth sampling resistor R5, a sixth sampling resistor R6 and a seventh sampling resistor R7, one end of the fifth sampling resistor R5 is connected with the other end of the second sampling resistor R2 and the other end of the fourth sampling resistor R4, the other end of the fifth sampling resistor R5 is connected with one end of the sixth sampling resistor R6, the other end of the sixth sampling resistor R6 is connected with one end of the seventh sampling resistor R7 and the voltage stabilizing and filtering module, and the other end of the seventh sampling resistor R7 is connected with the voltage stabilizing and filtering module and grounded.
In this embodiment, the resistances of the first sampling resistor R1, the second sampling resistor R2, the third sampling resistor R3, and the fourth sampling resistor R4 are all 4.7M Ω (4.7 megaohms), the resistances of the fifth sampling resistor R5 and the sixth sampling resistor R6 are 1.5M Ω (1.5 megaohms), and the resistance of the seventh sampling resistor R7 is 300K Ω (300 kiloohms). With reference to the SSS diagram, when the sampling unit obtains a 220V voltage from the AC input filter circuit 100, the 220V AC voltage is sampled for the first time through the first sampling resistor R1 and the second sampling resistor R2, or the third sampling resistor R3 and the fourth sampling resistor R4, and then sampled for the second time through the fifth sampling resistor R5, the sixth sampling resistor R6 and the seventh sampling resistor R7, and the obtained third sampling voltage is: VA3 ═ 220V (0.3M Ω/12.7M Ω), giving VA3 equal to about 5.19V. This voltage coincides with the voltage of the input VCC of the LLC control chip U1. And finally, outputting the third sampling voltage to a voltage stabilization filter circuit for filtering and voltage stabilization.
It should be noted that, in this embodiment, the resistances of the first sampling resistor R1, the second sampling resistor R2, the third sampling resistor R3, the fourth sampling resistor R4, the fifth sampling resistor R5, the sixth sampling resistor R6, and the seventh sampling resistor R7 may be set according to a specific on-voltage of a switching device in the switching unit, which is only an example and is not limited herein.
Specifically, referring to fig. 2, in the present embodiment, the voltage stabilizing filter module includes a first filter capacitor C1 and a first zener diode DZ1, one end of the first filter capacitor C1 is connected to the other end of the sixth sampling resistor R6, one end of the seventh sampling resistor R7, an output end of the first zener diode DZ1, and the switch unit, and the other end of the first filter capacitor C1 is connected to the input end of the first zener diode DZ1, and the switch unit is connected to the ground.
In specific implementation, in this embodiment, the first filter capacitor C1 filters the third sampling voltage into a stable dc voltage and outputs the stable dc voltage to the switch unit; the first zener diode DZ1 is a zener diode with a voltage of 5.1V, and the first zener diode DZ1 stabilizes the third sampling voltage at 5.1V; when the voltage output by the AC input filter circuit 100 is higher than 220V, the third sampling voltage output by the sampling circuit is also higher than 5.19V, and at this time, as long as the third sampling voltage does not exceed the reverse breakdown voltage of the first zener diode DZ1, the first zener diode DZ1 stabilizes the voltage at about 5.1V and outputs the stabilized voltage to the switching unit.
Further, referring to fig. 2, in the present embodiment, the switching unit includes a first MOS transistor Q1, a second MOS transistor Q2, a clamping resistor R0D1, a discharging resistor R0D2, and a first capacitor C2, a gate of the first MOS transistor Q1 is connected to the output end of the first voltage regulator diode DZ1, one end of the first filter capacitor C1, the other end of the sixth sampling resistor R6, and one end of the seventh sampling resistor R7, a source of the first MOS transistor Q1 is grounded, a drain of the first MOS transistor Q1 is connected to a gate of the second MOS transistor Q2, one end of the first capacitor C2, and one end of the clamping resistor R0D1, a source of the second MOS transistor Q2 and the other end of the first capacitor C2 are grounded, a drain of the second MOS transistor Q2 is connected to one end of the discharging resistor R0D2, and the other end of the discharging resistor R0D2 is connected to the clamping resistor R460D 46300 and the LLC circuit 400.
In specific implementation, in this embodiment, when the input plug 10 of the television power supply is powered on and outputs to the AC input filter circuit 100, the AC input filter circuit 100 filters the input voltage to output a 220V voltage, at this time, the first MOS transistor Q1 receives the 5.1V dc voltage filtered by the first filter capacitor C1, the first MOS transistor Q1 is turned on, and the source and the drain of the first MOS transistor Q1 are turned on to ground. Therefore, the gate of the second MOS transistor Q2 is clamped to low (0.2V) to ground by the first MOS transistor Q1, and the second MOS transistor Q2 is not conductive. The clamping resistor R0D1 is connected with the LLC control chip U1 and the PFC control chip U2, and is connected with chip input voltage SUPIC (namely voltage SUPIC), so that the input voltage clamping resistor R0D1 of the LLC control chip U1 and the PFC control chip U2 is clamped at normal working voltage and cannot be pulled down. When the input plug 10 is powered down, resulting in no voltage output from the AC input filter circuit 100, the input voltage of the sampling circuit is 0V, so that the gate of the first MOS transistor Q1 has no voltage, and the source and drain of the first MOS transistor Q1 are in a high impedance state. At this time, since the gate of the second MOS transistor Q2 is connected to the clamp resistor R0D1, the gate voltage of the second MOS transistor Q2 becomes high, and the second MOS transistor Q2 is turned on. At this time, after the voltage SUPIC is input to the PFC electrolytic capacitor 302 in the PFC circuit 300 through the first transformer output chip, the voltage is rapidly discharged to the ground through the discharge resistor R0D2, and the electric quantity stored in the PFC electrolytic capacitor 302 is directly and completely released, so that the PFC control chip U2 and the LLC control chip U1 stop working, the output of the television power supply is immediately stopped, the television loses power supply, and the indicator light is turned off. If the input plug 10 is powered on quickly after power failure, the chip input voltage SUPIC is clamped by the clamping resistor R0D1, the PFC control chip U2 and the LLC control chip U1 work normally, and the television is also turned on normally.
Referring to fig. 3, based on the reverse switch circuit 600, the present invention further provides a television power supply, which includes a power board connected to a television main board and an LED display screen, wherein the power board is provided with an AC input filter circuit 100, a first rectifier circuit 200, a PFC circuit 300, an LLC circuit 400, a secondary rectifier circuit 500, and the reverse switch circuit 600 as described above;
the AC input filter circuit 100 is connected to the input plug 10, AC power is input to the AC input filter circuit 100 through the input plug 10, the AC power is input and filtered by the AC input filter circuit 100 and output to the first rectifier circuit 200 and the reverse switch circuit 600, the AC power is rectified by the first rectifier circuit 200 and output to the PFC circuit 300, power correction is performed by the PFC circuit 300 and output to the LLC circuit 400, voltage output control is performed by the LLC circuit 400 and output to the secondary rectifier circuit 500 and the reverse switch circuit 600, the reverse switch circuit 600 receives AC voltage of the AC input filter circuit 100 and then performs chip input voltage supclamp ic on the LLC circuit 400 and the PFC circuit 300, the secondary rectifier circuit 500 receives output voltage of the LLC circuit 400 and then performs rectification and supplies power to the main board and the LED display screen; when the AC input filter circuit 100 is powered down, the reverse switch circuit 600 is turned on in the reverse direction to rapidly discharge the chip input voltage SUPIC of the LLC control chip U1 and the PFC control chip U2 to ground. The television power supply disclosed by the invention is reversely started through the switch unit when the alternating current input is powered off, so that the voltage input into the LLC circuit 400 is quickly discharged to the ground, and the television power supply can quickly respond when the power is quickly powered off and on.
Specifically, referring to fig. 2 to fig. 4, in the present embodiment, the LLC circuit 400 includes a third MOS transistor Q3, a fourth MOS transistor Q4, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a first electrolytic capacitor CS1, a second electrolytic capacitor CS2, an eighth resistor R8, a ninth resistor R9, a first transformer T1, a first resonant capacitor C3, and an LLC control chip U1;
the other end of the clamping resistor R0D1 and the other end of the discharging resistor R0D2 are connected to the SUPIC pin of the LLC control chip U1, one end of the first electrolytic capacitor CS1, the output end of the first diode D1 and the PFC circuit 300, the input end of the first diode D1 is connected to one end of the second electrolytic capacitor CS2, the output end of the second diode D2 and the output end of the third diode D3, the other end of the first electrolytic capacitor CS1 and the other end of the second electrolytic capacitor CS2 are both grounded, the input end of the second diode D2 is connected to the fifteenth pin of the first transformer T1, the input end of the third diode D3 is connected to the seventeenth pin of the first transformer T1, the fifth pin of the first transformer T1 is connected to the source of the third MOS transistor Q3 and the drain of the fourth MOS transistor Q4, the sixth pin of the first transformer T1 is connected to one end of the first resonant capacitor C3, and the second resonant capacitor C3 is grounded, the ninth pin, the tenth pin, the eleventh pin, the twelfth pin, the thirteenth pin and the fourteenth pin of the first transformer T1 are all connected to the secondary rectification circuit 500, the seventh pin, the eighth pin and the sixteenth pin of the first transformer T1 are all connected to ground, the drain of the third MOS transistor Q3 is connected to the PFC circuit 300, the gate of the third MOS transistor Q3 is connected to the input of the fourth diode D4 and one end of the eighth resistor R8, the output of the fourth diode D4 and the other end of the eighth resistor R8 are both connected to one end of the tenth resistor R10, the other end of the tenth resistor R10 is connected to the GATEHS pin of the LLC control chip U1, the source of the fourth MOS transistor Q4 is connected to ground, the gate of the fourth MOS transistor Q4 is connected to the input of the fifth diode D5 and one end of the ninth resistor R9, the output of the fifth diode D5 and the other end of the ninth resistor R9 are both connected to one end of the eleventh resistor R11, the other end of the eleventh resistor R11 is connected to a GATELS pin of the LLC control chip U1.
Specifically, when the television power supply in this embodiment is powered on and operated normally, AC power is input from the input plug 10, and the AC power is supplied to the television main board through the AC input filter circuit 100, the first rectifier circuit 200, the PFC circuit 300, the LLC circuit 400, and the secondary rectifier circuit 500 in sequence; meanwhile, a fifteenth pin and a seventeenth pin of the first transformer T1 respectively output chip input voltage SUPIC to the second triode D2 and the third triode D3, and output the chip input voltage SUPIC to the PFC control chip, the LLC control chip, the clamp resistor R0D1, and the discharge resistor R0D2 through the first diode; at this time, the clamping resistor R0D1 clamps the chip input voltage SUPIC, and the working states of the PFC circuit 300 and the LLC circuit 400 are not affected, so that the television power supply operates normally. When the power of the television is off, the reverse switch circuit 600 is turned on reversely to rapidly discharge the chip input voltage SUPIC to the ground end through the discharge resistor R0D2, so that the PFC control chip U2 in the PFC circuit 300 and the LLC control chip U1 in the LLC circuit 400 both rapidly stop working, and when the chips are powered on again, the television power can normally supply power to the motherboard, and the motherboard can also normally work.
Based on the television power supply, the invention also correspondingly provides a television, which comprises a television mainboard and an LED display screen, and also comprises the television power supply, wherein the television power supply is connected with the television mainboard and the LED display screen. Since the television power supply has been described in detail above, it will not be described in detail here.
In summary, the reverse switch circuit, the television power supply and the television provided by the invention are connected with the AC input filter circuit, the PFC circuit and the LLC circuit, and the reverse switch circuit includes a sampling circuit, a voltage stabilizing filter module and a switch unit; when the alternating current input is powered on, the AC input filtering module filters the input alternating current and outputs the filtered alternating current to the sampling circuit, the sampling circuit samples the filtered alternating current and outputs a third sampling voltage to the voltage stabilizing filtering module, the voltage stabilizing filtering module filters and stabilizes the third sampling voltage and outputs direct current voltage to the switch unit, and finally the switch unit is conducted to clamp the voltage of the LLC control chip and the PFC control chip to be normal working voltage; when the alternating current input is powered off, the switching unit is reversely started to rapidly discharge the chip input voltages of the LLC control chip and the PFC control chip to the ground, so that the rapid oscillation stop of the chip is realized, and the television can be rapidly restarted when the alternating current input of the television power supply is powered off and is rapidly powered on again.
It should be understood that equivalents and modifications of the technical solution and inventive concept thereof may occur to those skilled in the art, and all such modifications and alterations should fall within the scope of the appended claims.
Claims (10)
1. A reverse switching circuit connected to an AC input filter circuit, a PFC circuit, and an LLC circuit, the reverse switching circuit comprising: the sampling circuit, the voltage stabilizing and filtering module and the switch unit;
when the alternating current input is powered on, the AC input filtering module filters the input alternating current and outputs the filtered alternating current to the sampling circuit, the sampling circuit samples the filtered alternating current and outputs a third sampling voltage to the voltage stabilizing filtering module, the voltage stabilizing filtering module filters and stabilizes the third sampling voltage and outputs direct current voltage to the switch unit, and finally the switch unit is conducted to clamp the voltage of the LLC control chip and the PFC control chip to be normal working voltage;
when the alternating current input is powered off, the switching unit is reversely started to rapidly discharge the chip input voltages of the LLC control chip and the PFC control chip to the ground.
2. The reverse switch circuit according to claim 1, wherein the sampling circuit comprises a first sampling unit, a second sampling unit and a third sampling unit, the first sampling unit samples the voltage of the zero line and outputs a first sampling voltage to the third sampling unit, the second sampling unit outputs a second sampling voltage to the third sampling unit by using the voltage of the live line, the third sampling unit samples the first sampling voltage or the second sampling voltage and performs secondary sampling to obtain a third sampling voltage, and then the third sampling voltage is output to the voltage stabilizing and filtering module.
3. The reverse switch circuit according to claim 2, wherein the first sampling unit comprises a first sampling resistor and a second sampling resistor, one end of the first sampling resistor is connected to a zero line of an output end of the AC input filter module, the other end of the first sampling resistor is connected to one end of the second sampling resistor, and the other end of the second sampling resistor is connected to the second sampling power supply and the third sampling unit.
4. The backward switch circuit of claim 3, wherein the second sampling unit comprises a third sampling resistor and a fourth sampling resistor, one end of the third sampling resistor is connected to the output end of the AC input filter module in a live wire manner, the other end of the third sampling resistor is connected to one end of the fourth sampling resistor, and the other end of the fourth sampling resistor is connected to one end of the second sampling resistor and the third sampling unit.
5. The backward switch circuit of claim 4, wherein the third sampling unit comprises a fifth sampling resistor, a sixth sampling resistor and a seventh sampling resistor, one end of the fifth sampling resistor is connected to the other end of the second sampling resistor and the other end of the fourth sampling resistor, the other end of the fifth sampling resistor is connected to one end of the sixth sampling resistor, the other end of the sixth sampling resistor is connected to one end of the seventh sampling resistor and the voltage stabilizing filter module, and the other end of the seventh sampling resistor is connected to the voltage stabilizing filter module and grounded.
6. The reverse switch circuit of claim 5, wherein the voltage stabilizing filter module comprises a first filter capacitor and a first voltage stabilizing diode, one end of the first filter capacitor is connected to the other end of the sixth sampling resistor, one end of the seventh sampling resistor, the output end of the first voltage stabilizing diode and the switch unit, and the other end of the first filter capacitor is connected to the input end of the first voltage stabilizing diode and the switch unit and is connected to ground.
7. The reverse switch circuit according to claim 6, wherein the switch unit includes a first MOS transistor, a second MOS transistor, a clamping resistor, a discharging resistor, and a first capacitor, a gate of the first MOS transistor is connected to the output terminal of the first zener diode, one end of the first filter capacitor, the other end of the sixth sampling resistor, and one end of the seventh sampling resistor, a source of the first MOS transistor is grounded, a drain of the first MOS transistor is connected to the gate of the second MOS transistor, one end of the first capacitor, and one end of the clamping resistor, a source of the second MOS transistor and the other end of the first capacitor are grounded, a drain of the second MOS transistor is connected to one end of the discharging resistor, and the other end of the discharging resistor is connected to the other end of the clamping resistor and the PFC circuit and the LLC circuit.
8. A television power supply comprises a power supply board connected with a television main board and an LED display screen, and is characterized in that an AC input filtering module, a first rectifying circuit, a PFC circuit, an LLC circuit, a secondary rectifying circuit and a reverse switch circuit as claimed in any one of claims 1-7 are arranged on the power supply board;
the AC input filter module is connected with an input plug, AC is accessed by the input plug and transmitted to the AC input filter module, the AC is input and filtered by the AC input filter module and is output to the first rectifying circuit and the reverse switch circuit, the AC is rectified by the first rectifying circuit and is output to the PFC circuit, the power of the PFC circuit is corrected and is output to the LLC circuit, the LLC circuit is used for voltage output control and is output to the secondary rectifying circuit and the reverse switch circuit, the reverse switch circuit is used for chip input voltage clamping on the LLC circuit and the PFC circuit after receiving the AC voltage of the AC input filter module, and the secondary rectifying circuit is used for rectifying after receiving the output voltage of the LLC circuit and supplying power to the mainboard and the LED display screen;
and when the AC input filter module is powered off, the reverse switch circuit is reversely started to rapidly discharge the chip input voltages of the LLC control chip and the PFC control chip to the ground.
9. The television power supply according to claim 8, wherein the LLC circuit comprises a third MOS transistor, a fourth MOS transistor, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a first electrolytic capacitor, a second electrolytic capacitor, an eighth resistor, a ninth resistor, a first transformer, a first resonant capacitor, and an LLC control chip;
the other end of the clamping resistor and the other end of the discharge resistor are connected with an SUPIC pin of an LLC control chip, one end of a first electrolytic capacitor, the output end of a first diode and a PFC circuit, the input end of the first diode is connected with one end of a second electrolytic capacitor, the output end of a second diode and the output end of a third diode, the other end of the first electrolytic capacitor and the other end of the second electrolytic capacitor are grounded, the input end of the second diode is connected with a fifteenth pin of a first transformer, the input end of the third diode is connected with a seventeenth pin of the first transformer, a fifth pin of the first transformer is connected with a source electrode of a third MOS (metal oxide semiconductor) transistor and a drain electrode of a fourth MOS (metal oxide semiconductor) transistor, a sixth pin of the first transformer is connected with one end of a first resonant capacitor, the other end of the first resonant capacitor is grounded, a ninth pin, a pin of the first transformer, and an output end of a, The tenth pin, the eleventh pin, the twelfth pin, the thirteenth pin and the fourteenth pin are all connected with the secondary rectifying circuit, the seventh pin, the eighth pin and the sixteenth pin of the first transformer are all grounded, the drain electrode of the third MOS tube is connected with the PFC circuit, the grid electrode of the third MOS tube is connected with the input end of the fourth diode and one end of the eighth resistor, the output end of the fourth diode and the other end of the eighth resistor are both connected with one end of a tenth resistor, the GATEHS pin of the LLC control chip at the other end of the tenth resistor is connected, the source of the fourth MOS transistor is grounded, the grid electrode of the fourth MOS tube is connected with the input end of the fifth diode and one end of a ninth resistor, the output end of the fifth diode and the other end of the ninth resistor are both connected with one end of an eleventh resistor, and the other end of the eleventh resistor is connected with a GATELS pin of the LLC control chip.
10. A television set comprising a television motherboard and an LED display screen, further comprising a television power supply as claimed in any one of claims 8 or 9, said television power supply being connected to the television motherboard and the LED display screen.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911362665.6A CN110994967A (en) | 2019-12-25 | 2019-12-25 | Reverse switching circuit, television power supply and television |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911362665.6A CN110994967A (en) | 2019-12-25 | 2019-12-25 | Reverse switching circuit, television power supply and television |
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| CN110994967A true CN110994967A (en) | 2020-04-10 |
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| CN201911362665.6A Pending CN110994967A (en) | 2019-12-25 | 2019-12-25 | Reverse switching circuit, television power supply and television |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113395807A (en) * | 2021-06-01 | 2021-09-14 | 广东科谷智能科技有限公司 | Dimming circuit, PCB and dimming power supply |
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