CN204993097U - Turn over and swash formula alternately load regulation switching power supply and TV - Google Patents

Abstract

The utility model discloses a flyback type cross load regulation switching power supply and a TV, comprising an EMI filter rectification module, a flyback topology module, a first rectification filter output module, a second rectification filter output module, a feedback module and a step-down sampling module. After the AC voltage is subjected to EMI filtering and rectification processing by the EMI filtering and rectifying module, it is boosted by the flyback topology module, rectified and filtered by the first rectifying and filtering output module to output the first voltage, and at the same time rectified and filtered by the second rectifying and filtering output module The second voltage is output, the feedback module feeds back the first voltage and the second voltage to the flyback topology module, the step-down sampling module samples the first voltage of the first rectification and filtering output module, and when the first voltage is greater than the preset voltage, by performing The step-down process reduces the output voltage of the first rectification and filtering output module, thereby protecting the filter capacitor in the first rectification and filtering output module from being damaged, and the power consumption of the step-down sampling module is low, so that the standby power consumption of the TV is low.

Description

Flyback Cross Load Regulation Switching Power Supplies and TVs

technical field

The utility model relates to the technical field of switching power supply circuits, in particular to a flyback type crossover load regulation switching power supply and a television.

Background technique

Switching power supply is a kind of power supply that uses modern power electronic technology to control the time ratio of switching on and off to maintain a stable output voltage. With the development and innovation of power electronics technology, switching power supply technology is constantly innovating. At present, switching power supply is widely used in almost all electronic equipment due to its small size, light weight and high efficiency. It is an indispensable power supply method for the rapid development of today's electronic information industry.

LED TV power supply generally uses a dual-output flyback topology switching power supply circuit, as shown in Figure 1, generally uses +12V as the main voltage output, +130V as the auxiliary voltage output, which requires a more accurate range of +12V, and +130V As the boost input of the backlight voltage, there is generally BOOST boost (boost boost is a switching DC boost) constant current as the backlight drive after +130V, so the voltage range of the +130V output is not very demanding. As long as the withstand voltage of the filter capacitor C1 is not exceeded.

In order to meet the above requirements, the general practice is: +12V is used as the main feedback, and the feedback current is relatively large, while +130V is used as the auxiliary feedback, and the feedback current is relatively small, that is, I1 [(+12V-2.5V)/R1] is much larger than I2 [(+130V-2.5V)/(R2+R3)], where 2.5V is the turn-on voltage of the controllable voltage regulator, R1 is the resistance of the first resistor, R2 is the resistance of the second resistor, R3 is the resistance value of the third resistor.

In the above method, if both +12V and +130V have a certain load, +12V can be relatively stable. However, when the +130V load is zero, that is, the TV backlight is not turned on, and the +12V load is heavy, the +130V voltage will rise very high due to the cross-load adjustment problem, and there is a risk of exceeding the withstand voltage value of the filter capacitor C1. There are great reliability risks.

In order to solve the above problems, the current mitigation method is to add a dummy load on the +130V path, such as the fourth resistor R4 and the fifth resistor R5, but this will increase the standby power consumption and waste costs. Taking 130V as an example, the fourth resistor R4 and the fifth resistor R5 are both 100k/2W resistors, the consumed standby power . It can be seen that when the TV backlight is not turned on in this way, the standby power consumption is increased, which is not conducive to energy saving.

Thereby prior art still needs to improve and improve.

Utility model content

In view of the shortcomings of the above-mentioned prior art, the purpose of this utility model is to provide a flyback cross load regulation switching power supply and a TV, by increasing the amount of feedback to reduce the output voltage to protect the filter capacitor on the high-voltage booster branch .

In order to achieve the above object, the utility model has taken the following technical solutions:

A flyback cross load regulation switching power supply, including an EMI filter rectifier module, a flyback topology module, a first rectifier filter output module, a second rectifier filter output module, and a feedback module; the AC voltage is EMI filtered by the EMI filter rectifier module After rectification and rectification processing, the flyback topology module boosts the voltage, and the first voltage is rectified and filtered by the first rectification and filtering output module, and the second voltage is rectified and filtered by the second rectification and filtering output module, and the feedback module The first voltage and the second voltage are fed back to the flyback topology module, and the flyback cross load regulation switching power supply also includes a function for sampling the first voltage, and when the first voltage is greater than a preset voltage A step-down sampling module for performing step-down processing, the step-down sampling module is connected to the first rectification and filtering output module and the feedback module.

In the flyback cross load regulation switching power supply, the step-down sampling module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a triode and the first controllable voltage-stabilizing source, one end of the first resistor is connected to one end of the fifth resistor, one end of the seventh resistor and the output end of the first rectification and filtering output module, and the other end of the first resistor passes through the first The second resistor and the third resistor are connected to the reference end of the first controllable voltage stabilizer and one end of the fourth resistor, the other end of the fourth resistor is grounded to the anode of the first controllable voltage stabilizer, and the first controllable voltage stabilizer The cathode of the voltage regulator is connected to the base of the triode and the other end of the fifth resistor through the sixth resistor, the collector of the triode is connected to the feedback module, and the emitter of the triode is connected to the other end of the seventh resistor.

In the flyback cross load regulation switching power supply, the step-down sampling module further includes a first capacitor, one end of the first capacitor is connected to the reference end of the controllable voltage regulator, and the other end of the first capacitor is grounded .

In the flyback cross load regulation switching power supply, the flyback topology module includes a flyback transformer, the first rectification and filtering output module includes a diode and a second capacitor, and the anode of the diode is connected to the flyback transformer. The terminal with the same name as the first secondary winding, the cathode of the diode is the output terminal of the first rectifying and filtering output module, one terminal connecting the feedback module and the seventh resistor, one terminal of the fifth resistor and one terminal of the first resistor, and also through the second The capacitor is grounded; the opposite end of the first secondary winding of the flyback transformer is connected to the same end of the second secondary winding of the flyback transformer.

In the flyback cross load regulation switching power supply, the feedback module includes an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a third capacitor, An optocoupler and a second controllable voltage regulator, one end of the ninth resistor is connected to one end of the fifth resistor, one end of the seventh resistor and the output end of the first rectification and filtering output module, and the other end of the ninth resistor is passed through The tenth resistor is connected to the collector of the triode; one end of the eighth resistor is connected to the output end of the second rectification and filtering output module, and the first end of the optocoupler is connected through the eleventh resistor, and the other end of the eighth resistor is connected to The reference electrode of the second controllable voltage stabilization source is also connected to the cathode of the second controllable voltage stabilization source and the second end of the optocoupler in turn through the third capacitor and the twelfth resistor, and is also grounded through the thirteenth resistor. The anodes of the two controllable voltage regulators are grounded, the fourth end of the optocoupler is connected to the flyback topology module, and the third end of the optocoupler is grounded.

In the flyback cross load regulation switching power supply, the first voltage is above 130V, and the second voltage is 12V.

In the flyback cross load regulation switching power supply, the resistance value of the first resistor is 1 megaohm, the resistance value of the second resistor is 1 megaohm, the resistance value of the third resistor is 1 megaohm, and the resistance value of the second resistor is 1 megaohm. The resistance value of the four resistors is 43 kohms.

A television comprising the flyback cross load regulation switching power supply as described above.

Compared with the prior art, the flyback cross load regulation switching power supply and TV provided by the utility model include EMI filter rectification module, flyback topology module, first rectification filter output module, second rectification filter output module, feedback module and a step-down sampling module, the AC voltage is processed by the EMI filter and rectifier module for EMI filtering and rectification, then boosted by the flyback topology module, rectified and filtered by the first rectifier and filter output module to output the first voltage, and at the same time The second rectification and filtering output module performs rectification and filtering to output a second voltage, the feedback module feeds back the first voltage and the second voltage to the flyback topology module, and the step-down sampling module samples the first rectification and filtering output module When the first voltage is greater than the preset voltage, the output voltage of the first rectification and filtering output module is reduced by increasing the feedback amount to reduce the output voltage of the first rectification and filtering output module, thereby protecting the filter capacitor in the first rectification and filtering output module from being damaged damage, and the power consumption of the step-down sampling module is low, so that the standby power consumption of the TV is low.

Description of drawings

FIG. 1 is a circuit diagram of a dual-output flyback topology switching power supply in the prior art.

Fig. 2 is a circuit diagram of the flyback cross load regulation switching power supply provided by the utility model.

detailed description

The utility model provides a flyback cross-load regulation switching power supply and a TV. In order to make the purpose, technical solution and effect of the utility model clearer and clearer, the utility model is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

Please refer to Fig. 2, the flyback cross load regulation switching power supply provided by the utility model includes an EMI filter rectification module 10, a flyback topology module 20, a first rectification filter output module 30, a second rectification filter output module 40, and a feedback module 50 and a step-down sampling module 60. The EMI filter rectification module 10 is connected to the flyback topology module 20, and the flyback topology module 20 is connected to the input end of the first rectification filter output module 30 and the input end of the second rectification filter output module 40, and the first rectification filter output module The output terminal of 30 and the output terminal of the second rectification and filtering output module 40 are connected to the feedback module 50 , and the step-down sampling module 60 is connected to the first rectification and filtering output module 30 and the feedback module 50 .

The first rectifying and filtering output module 30 is an auxiliary output branch, and its output voltage is above +130V, that is, the first voltage is above +130V. The second rectification and filtering output module 40 is the main output branch, and its output voltage is +12V, that is, the first voltage is +12V. After the AC voltage is subjected to EMI filtering and rectification processing by the EMI filtering and rectifying module 10, it is boosted by the flyback topology module 20, rectified and filtered by the first rectifying and filtering output module 30 to output the first voltage, and at the same time passed through the second rectifying and filtering output module 40 performs rectification and filtering to output the second voltage, the feedback module 50 feeds back the first voltage and the second voltage to the flyback topology module 20, and the step-down sampling module 60 is used to sample the first voltage, when the When the first voltage is greater than the preset voltage, increase the feedback amount to perform step-down processing, so that the output voltage of the first rectification and filtering output module 30 is reduced, thereby protecting the electronic components (such as filter capacitors) in the first rectification and filtering output module 30, and The power consumption of the step-down sampling module 60 is low.

Please continue to refer to FIG. 2, the step-down sampling module 60 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a triode Q1 and the first controllable voltage regulator N1. One end of the first resistor R1 is connected to one end of the fifth resistor R5, one end of the seventh resistor R7 and the output end of the first rectification and filtering output module 30, and the other end of the first resistor R1 passes through the second resistor R2, The third resistor R3 is connected to the reference end of the first controllable voltage regulator N1 and one end of the fourth resistor R4, the other end of the fourth resistor R4 and the anode of the first controllable voltage regulator N1 are grounded, and the first The cathode of the controllable voltage regulator N1 is connected to the base of the transistor Q1 and the other end of the fifth resistor R5 through the sixth resistor R6, the collector of the transistor Q1 is connected to the feedback module 50, and the emitter of the transistor Q1 is connected to the other end of the seventh resistor R7. one end.

The first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are sampling resistors, the resistance of the first resistor R1 is 1 megaohm, and the resistance of the second resistor R2 is 1 megaohm 1. The resistance value of the third resistor R3 is 1 MΩ, and the resistance value of the fourth resistor R4 is 43 KΩ. The first controllable voltage stabilization source N1 is used to detect the sampling voltage. When the output voltage of the first rectification and filtering output module 30 is greater than a preset voltage (such as 200V), the first controllable voltage stabilization source N1 is turned on, and the triode The base of Q1 becomes low level and turned on, so that the seventh resistor R7 is connected in parallel with the auxiliary feedback part of the feedback module 50, thereby increasing the feedback amount, making the output voltage of the first rectification and filtering output module 30 lower, thereby protecting Electronic components of the first rectification and filtering output module 30 are provided.

Further, the step-down sampling module 60 also includes a first capacitor C1, one end of the first capacitor C1 is connected to the reference end of the controllable voltage regulator, and the other end of the first capacitor C1 is grounded, and the first capacitor C1 is The filter capacitor is used to stabilize the reference voltage of the first controllable voltage regulator N1.

Please continue to refer to FIG. 2 , the flyback topology module 20 includes a flyback transformer T1, the first rectification and filtering output module 30 includes a diode D1 and a second capacitor C2, and the anode of the diode D1 is connected to the second capacitor of the flyback transformer T1. The end of the same name of the primary winding, the cathode of the diode D1 is the output end of the first rectification and filtering output module 30, the end connecting the feedback module 50 and the seventh resistor R7, one end of the fifth resistor R5 and one end of the first resistor R1 , is also grounded through the second capacitor C2; the opposite end of the first secondary winding of the flyback transformer T1 is connected to the same end of the second secondary winding of the flyback transformer T1.

Wherein, the primary winding part of the flyback transformer T1 is a flyback part, and the secondary winding part is a self-excited part. The diode D1 is a rectifier diode, the second capacitor C2 is a filter capacitor, and the step-down sampling module 60 is mainly used to reduce the output voltage of the first rectifier filter output module 30 to prevent damage to the second capacitor C2.

Please continue to refer to FIG. 2, the feedback module 50 includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a third capacitor C3, An optocoupler U1 and a second controllable voltage regulator N2. One end of the ninth resistor R9 is connected to one end of the fifth resistor R5, one end of the seventh resistor R7 and the output end of the first rectification and filtering output module 30, and the other end of the ninth resistor R9 is connected to the triode through the tenth resistor R10 The collector of Q1; one end of the eighth resistor R8 is connected to the output end of the second rectification and filtering output module 40, and is also connected to the first end of the optocoupler U1 through the eleventh resistor R11, and the other end of the eighth resistor R8 Connect the reference pole of the second controllable voltage source N2, and connect the cathode of the second controllable voltage source N2 and the second end of the optocoupler U1 through the third capacitor C3 and the twelfth resistor R12 in turn, and also through the thirteenth resistor R12 The resistor R13 is grounded, the anode of the second controllable voltage regulator N2 is grounded, the fourth end of the optocoupler U1 is connected to the flyback topology module 20 , and the third end of the optocoupler U1 is grounded.

Wherein, the eighth resistor R8 is the main feedback resistor, which is used to feed back the output voltage of the main output branch to the flyback topology module 20, and the ninth resistor R9 and the tenth resistor R10 are auxiliary feedback resistors, which are used to feed back the output voltage of the auxiliary output branch. The output voltage of the branch circuit is fed back to the flyback topology module 20, and the model of the optocoupler U1 is PC817B, which mainly plays an isolation role.

Please describe in detail the working principle of the flyback cross load regulation switching power supply of the present invention in conjunction with Figure 2:

In Figure 2, the thick solid line passing through the flyback transformer T1 and optocoupler U1 is the separation line between flyback and self-excitation, the left side of the thick solid line is the flyback part, and the right side of the thick solid line is the self-excitation part. When the voltage of the auxiliary output branch rises beyond 200V, the first controllable voltage regulator N1 is turned on, so that the transistor Q1 is turned on, so that the seventh resistor R7 is connected in parallel with the ninth resistor R9 and the tenth resistor R10, thereby increasing The amount of feedback reduces the output voltage of the auxiliary output branch, thereby protecting the first capacitor C1. After using the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4, the consumed standby power consumption for: , compared with the existing solution of increasing the dummy load, the standby power consumption is reduced by 300.

The utility model also provides a TV correspondingly, which includes the above-mentioned flyback cross load regulation switching power supply. Since the circuit structure and working principle of the flyback cross load regulation switching power supply have been described above, I won't repeat them here.

In summary, the flyback crossover load regulation switching power supply and TV provided by the utility model include an EMI filter rectifier module, a flyback topology module, a first rectifier filter output module, a second rectifier filter output module, a feedback module and Step-down sampling module, the AC voltage is subjected to EMI filtering and rectification processing by the EMI filtering and rectifying module, then boosted by the flyback topology module, rectified and filtered by the first rectifying and filtering output module to output the first voltage, and at the same time passed through the second The rectification and filtering output module performs rectification and filtering to output the second voltage, the feedback module feeds back the first voltage and the second voltage to the flyback topology module, and the step-down sampling module samples the second voltage of the first rectification and filtering output module. A voltage, when the first voltage is greater than the preset voltage, the output voltage of the first rectification and filtering output module is reduced by increasing the feedback amount to reduce the output voltage, thereby protecting the filter capacitor in the first rectification and filtering output module from being damaged, Moreover, the power consumption of the step-down sampling module is low, so that the standby power consumption of the TV is low.

It can be understood that those skilled in the art can make equivalent replacements or changes according to the technical solution of the utility model and its utility model concept, and all these changes or replacements should belong to the appended claims of the utility model protected range.

Claims (8)

1. an inverse-excitation type cross load regulation Switching Power Supply, comprises EMI filter rectification module, flyback topologies module, the first rectifying and wave-filtering output module, the second rectifying and wave-filtering output module and feedback module, alternating voltage carries out after EMI filtering and rectification process through EMI filter rectification module, boosted by flyback topologies module and process, carry out rectifying and wave-filtering through the first rectifying and wave-filtering output module and export the first voltage, carrying out rectifying and wave-filtering through the second rectifying and wave-filtering output module exports the second voltage simultaneously, described flyback topologies module is given by described first voltage and the second Voltage Feedback by described feedback module, it is characterized in that, described inverse-excitation type cross load regulation Switching Power Supply also comprises for the first voltage of sampling, the step-down sampling module of step-down process is carried out when described first voltage is greater than predeterminated voltage, described step-down sampling module connects the first rectifying and wave-filtering output module and feedback module.

2. inverse-excitation type cross load regulation Switching Power Supply according to claim 1, it is characterized in that, described step-down sampling module comprises the first resistance, second resistance, 3rd resistance, 4th resistance, 5th resistance, 6th resistance, 7th resistance, triode and the first controlled source of stable pressure, one end of described first resistance connects one end of the 5th resistance, one end of 7th resistance and the output of the first rectifying and wave-filtering output module, the other end of described first resistance is successively by the second resistance, 3rd resistance connects the reference edge of the first controlled source of stable pressure and one end of the 4th resistance, the other end of described 4th resistance and the plus earth of the first controlled source of stable pressure, the negative electrode of described first controlled source of stable pressure is by the base stage of the 6th resistance connecting triode and the other end of the 5th resistance, the collector electrode of triode connects feedback module, the emitter of triode connects the other end of the 7th resistance.

3. inverse-excitation type cross load regulation Switching Power Supply according to claim 2, it is characterized in that, described step-down sampling module also comprises the first electric capacity, and one end of described first electric capacity connects the reference edge of controlled source of stable pressure, the other end ground connection of the first electric capacity.

4. inverse-excitation type cross load regulation Switching Power Supply according to claim 2, it is characterized in that, described flyback topologies module comprises flyback transformer, first rectifying and wave-filtering output module comprises diode and the second electric capacity, the positive pole of described diode connects the Same Name of Ends of the first secondary winding of flyback transformer, described diode cathode is the output of the first rectifying and wave-filtering output module, the one end connecting feedback module and the 7th resistance, one end of the 5th resistance and one end of the first resistance, also by the second capacity earth; The different name end of the first secondary winding of described flyback transformer connects the Same Name of Ends of the second subprime winding of flyback transformer.

5. inverse-excitation type cross load regulation Switching Power Supply according to claim 2, it is characterized in that, described feedback module comprises the 8th resistance, the 9th resistance, the tenth resistance, the 11 resistance, the 12 resistance, the 13 resistance, the 3rd electric capacity, optocoupler and the second controlled source of stable pressure, one end of described 9th resistance connects the output of one end of the 5th resistance, one end of the 7th resistance and the first rectifying and wave-filtering output module, and the other end of described 9th resistance is by the collector electrode of the tenth resistance connecting triode; One end of described 8th resistance is connected the output of the second rectifying and wave-filtering output module, is also connected the 1st end of optocoupler by the 11 resistance, the other end of described 8th resistance connect the second controlled source of stable pressure reference pole, also successively by the 3rd electric capacity to be connected with the 12 resistance the negative electrode of the second controlled source of stable pressure and optocoupler the 2nd end, also by the 13 grounding through resistance, the plus earth of described second controlled source of stable pressure, 4th end of described optocoupler connects flyback topologies module, the 3rd end ground connection of optocoupler.

6. inverse-excitation type cross load regulation Switching Power Supply according to claim 1, it is characterized in that, described first voltage is more than 130V, and the second voltage is 12V.

7. inverse-excitation type cross load regulation Switching Power Supply according to claim 2, it is characterized in that, the resistance of described first resistance is 1 megohm, the resistance of the second resistance is 1 megohm, the resistance of the 3rd resistance is 1 megohm, the resistance of the 4th resistance is 43 kilohms.

8. a TV, is characterized in that, comprises the inverse-excitation type cross load regulation Switching Power Supply as described in claim 1-7 any one.