CN107317481B - Multi-stage DC-DC converter, power supply device and display equipment - Google Patents
Multi-stage DC-DC converter, power supply device and display equipment Download PDFInfo
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- CN107317481B CN107317481B CN201710741322.5A CN201710741322A CN107317481B CN 107317481 B CN107317481 B CN 107317481B CN 201710741322 A CN201710741322 A CN 201710741322A CN 107317481 B CN107317481 B CN 107317481B
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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
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
Abstract
The invention discloses a multistage DC-DC converter, a power supply device and a display device, wherein the multistage DC-DC converter is connected with the power supply converter and a backlight light source and comprises N stages of voltage conversion modules which are connected in series, wherein N is more than or equal to 2; the first-stage voltage conversion module receives the direct-current voltage output by the power converter, converts the direct-current voltage into a first voltage and outputs the first voltage to the second-stage voltage conversion module, the second-stage voltage conversion module continues to perform voltage conversion on the first voltage and outputs a second voltage, and the like. The output voltage of the DC-DC converter can be flexibly adjusted through step-by-step voltage conversion so as to meet the voltage specification requirements of different backlight sources, improve the compatibility of the power supply device and effectively improve the production test efficiency of the display module.
Description
Technical Field
The invention relates to the technical field of power supplies of electric appliances, in particular to a multistage DC-DC converter, a power supply device and display equipment.
Background
As is known, the lcd screen itself does not emit light, and other light sources are needed to emit light, and the LED light source is the most widely used light source in lcd tv and lcd. In the current commonly used power supply scheme of the LED liquid crystal backlight source, as shown in fig. 1, a power converter converts alternating current into direct current voltage with a certain specification, and a boost DC-DC converter boosts the direct current to the voltage required by the backlight source. The disadvantage of this method is that the boost DC-DC is limited by the duty ratio of the switching tube, i.e. the ratio of the output voltage to the input voltage, if the duty ratio of the boost DC-DC switching tube is too large, the power conversion efficiency will be low, the heat generation of the switching tube will be too large, the thermal design of the switching tube will become difficult, the service life of the power supply will be seriously affected, and the design will be troubled.
Therefore, in order to solve this problem, a power converter is designed to have a reasonable output voltage according to the voltage specification of the backlight source, so as to meet the performance requirement of the boost DC-DC. However, this method may cause different screens to require different power supplies, resulting in a variety of power supplies, for example, LED backlights have different sizes and different positions of backlight placement, and have different voltage specifications, as low as ten volts and as high as one hundred volts. It can be seen that the existing backlight power supply scheme cannot be compatible with the voltage specification requirements of different backlight sources, so that the number and the types of the power supply devices are too many, and the production test efficiency of the display module is greatly influenced.
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 multi-stage DC-DC converter, a power supply device and a display device, wherein the output voltage of the DC-DC converter can be flexibly adjusted through stage-by-stage voltage conversion so as to meet the voltage specification requirements of different backlight sources, improve the compatibility of the power supply device and effectively improve the production test efficiency of a display module.
In order to achieve the purpose, the invention adopts the following technical scheme:
a multi-stage DC-DC converter is connected with a power converter and a backlight light source and comprises N stages of voltage conversion modules which are connected in series, wherein N is more than or equal to 2; the first-stage voltage conversion module receives the direct-current voltage output by the power converter, converts the direct-current voltage into a first voltage and outputs the first voltage to the second-stage voltage conversion module, the second-stage voltage conversion module continues to perform voltage conversion on the first voltage and outputs a second voltage, and the like.
In the multi-stage DC-DC converter, each voltage conversion module comprises a boosting unit and a voltage regulation unit, the voltage regulation unit outputs a corresponding feedback signal to the boosting unit according to a received voltage regulation instruction, and the boosting unit receives the A-1 voltage output by the previous-stage voltage conversion module, converts the A-1 voltage into the A voltage according to the feedback signal and outputs the A voltage to the next-stage voltage conversion module; wherein A is the stage number of the current voltage conversion module.
In the multi-stage DC-DC converter, when A is equal to 1, the boosting unit receives a direct-current voltage output by a power converter, converts the direct-current voltage into a first voltage according to the feedback signal and outputs the first voltage to the second-stage voltage conversion module;
and when A is equal to N, the boosting unit receives the N-1 voltage output by the N-1 level voltage conversion module, outputs the N-1 voltage as a preset power supply voltage according to the feedback signal and then outputs the preset power supply voltage to the backlight light source.
In the multi-stage DC-DC converter, the voltage regulating unit comprises a resistance setting subunit, a sampling feedback subunit and a plurality of switch subunits, each switch subunit is turned on or turned off according to a received voltage regulating instruction to regulate the resistance value of the resistance setting subunit, and the sampling feedback subunit outputs a corresponding feedback signal to the boosting unit according to the resistance value of the current resistance setting subunit.
In the multi-stage DC-DC converter, each switch subunit comprises a first resistor, a second resistor and a triode, one end of the first resistor is connected with a voltage regulation instruction input end, and the other end of the first resistor is connected with a base electrode of the triode and one end of the second resistor; the other end of the second resistor is connected with an emitting electrode of the triode and the ground; and the collector electrode of the triode is connected with the resistance setting subunit.
In the multi-stage DC-DC converter, the resistance setting subunit comprises a ground resistance and a plurality of third resistances, the number of the third resistances is equal to that of the switch subunits, one end of each third resistance is connected with one end of the ground resistance and the sampling feedback subunit, and the other end of each third resistance is correspondingly connected with one switch subunit.
In the multi-stage DC-DC converter, the sampling feedback subunit comprises a sampling resistor, one end of the sampling resistor is connected with the resistor setting subunit, and the other end of the sampling resistor is connected with the feedback end of the boosting unit.
In the multi-stage DC-DC converter, the triode is an NPN type triode.
A power supply device comprises an outer shell, wherein a PCB is arranged in the outer shell, a power converter and a multi-stage DC-DC converter are arranged on the PCB, an alternating current input voltage is converted into a direct current voltage by the power converter, the direct current voltage is output to the multi-stage DC-DC converter, and the multi-stage DC-DC converter carries out stage-by-stage voltage conversion on the direct current voltage and outputs a preset power supply voltage to a backlight light source.
A display device comprising a backlight source, further comprising a power supply arrangement as described above, the backlight source being powered by said power supply arrangement.
Compared with the prior art, in the multistage DC-DC converter, the power supply device and the display equipment provided by the invention, the multistage DC-DC converter is connected with the power supply converter and the backlight light source and comprises N stages of voltage conversion modules which are connected in series, wherein N is more than or equal to 2; the first-stage voltage conversion module receives the direct-current voltage output by the power converter, converts the direct-current voltage into a first voltage and outputs the first voltage to the second-stage voltage conversion module, the second-stage voltage conversion module continues to perform voltage conversion on the first voltage and outputs a second voltage, and the like. The output voltage of the DC-DC converter can be flexibly adjusted through step-by-step voltage conversion so as to meet the voltage specification requirements of different backlight sources, improve the compatibility of the power supply device and effectively improve the production test efficiency of the display module.
Drawings
Fig. 1 is a block diagram showing a structure of a power supply device in the related art;
fig. 2 is a block diagram of a power supply apparatus according to the present invention;
fig. 3 is a block diagram of a multi-stage DC-DC converter according to the present invention;
fig. 4 is a circuit diagram of a multi-stage DC-DC converter provided by the present invention.
Detailed Description
The invention provides a multi-stage DC-DC converter, a power supply device and a display device, wherein the output voltage of the DC-DC converter can be flexibly adjusted through stage-by-stage voltage conversion so as to meet the voltage specification requirements of different backlight sources, the compatibility of the power supply device is improved, and the production test efficiency of a display module is effectively improved.
In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 2, the power supply device according to the present invention includes a housing (not shown in the figure), a PCB (not shown in the figure) is disposed in the housing, a power converter 10 and a multi-stage DC-DC converter 20 are disposed on the PCB, the multi-stage DC-DC converter 20 is connected to the power converter 10 and the backlight light source, the power converter 10 converts an ac input voltage into a DC voltage and outputs the DC voltage to the multi-stage DC-DC converter 20, and the multi-stage DC-DC converter 20 performs a step-by-step voltage conversion on the DC voltage and outputs a predetermined power supply voltage to the backlight light source, so as to normally supply power to the backlight light source.
The multi-stage DC-DC converter 20 includes N stages of voltage conversion modules 21 connected in series, where N is greater than or equal to 2, that is, the multi-stage DC-DC converter 20 includes at least two voltage conversion modules 21 connected in series, the number of the voltage conversion modules 21 can be adjusted according to specific input voltage and output voltage requirements, when performing voltage conversion, the first stage voltage conversion module 21 receives the DC voltage output by the power converter 10 and converts the DC voltage into a first voltage to output to the second stage voltage conversion module 21, the second voltage conversion module 21 continues to perform voltage conversion after receiving the first voltage and outputs a second voltage, and so on, after controlling each stage of voltage conversion module 21 to perform voltage conversion in sequence, the nth stage voltage conversion module 21 outputs a preset power supply voltage to the backlight light source. By adopting the mode of step-by-step voltage conversion, the output voltage of each level of voltage conversion module 21 can be flexibly set, so that the purpose of outputting different power supply voltages can be achieved by respectively setting the output voltage of each level of voltage conversion module 21 and the number of the voltage conversion modules 21, one power converter 10 can adapt to backlight light sources with various voltage specification requirements, the power converter 10 with specific output voltage is not required to be specially designed for each backlight light source, the compatibility of a power supply device is greatly improved, and the production and test cost is saved.
Specifically, referring to fig. 3, in the multi-stage DC-DC converter 20, each voltage conversion module 21 includes a voltage boosting unit 211 and a voltage regulating unit 212, all the voltage boosting units 211 are sequentially connected in series, and each voltage boosting unit 211 is correspondingly connected to one voltage regulating unit 212, that is, each voltage conversion module 21 can set and regulate the output voltage of the voltage boosting unit 211 through the voltage regulating unit 212, specifically, the voltage regulating unit 212 outputs a corresponding feedback signal to the voltage boosting unit 211 according to a received voltage regulating instruction, and the voltage boosting unit 211 receives the a-1 th voltage output by the previous voltage conversion module 21, converts the a-1 th voltage into the a-th voltage according to the feedback signal, and outputs the a-1 th voltage to the next voltage conversion module 21; where a is the number of stages of the current voltage conversion module 21. For example, the boosting unit 211 in the second-stage voltage module receives the first voltage output by the boosting unit 211 in the first-stage voltage module, converts the first voltage into the second voltage according to the received feedback signal, outputs the second voltage to the boosting unit 211 in the third-stage voltage conversion module 21, and continues the voltage conversion process.
Specifically, when a is equal to 1, the voltage boost unit 211 receives the dc voltage output by the power converter 10, converts the dc voltage into a first voltage according to the feedback signal, and outputs the first voltage to the second-stage voltage conversion module 21; that is, the boosting unit 211 in the first-stage voltage converting module 21 receives the dc voltage output by the power converter 10, converts the dc voltage into the first voltage according to the feedback signal output by the voltage regulating unit 212 in the first-stage voltage converting module 21, and outputs the first voltage to the second-stage voltage converting module 21.
When a is equal to N, the boosting unit 211 receives the N-1 th voltage output by the N-1 th stage voltage converting module 21, and outputs the N-1 th voltage as a preset power supply voltage to the backlight light source according to the feedback signal; in the last stage, the voltage boosting unit 211 in the nth stage voltage conversion module 21 receives the nth-1 voltage output by the voltage boosting unit 211 in the nth-1 stage voltage conversion module 21, and outputs the nth-1 voltage as the preset power supply voltage to the backlight light source according to the feedback signal output by the voltage adjusting unit 212 in the nth-1 stage voltage conversion module 21.
In the multi-stage DC-DC converter 20 provided by the present invention, each stage of the voltage conversion module 21 sets and adjusts the output voltage of the boosting unit 211 through the voltage adjusting unit 212, and can flexibly send a voltage adjusting instruction to each voltage adjusting unit 212 according to the voltage specification of the current backlight source, so that the preset power supply voltage of the multi-stage DC-DC converter 20 meets the current voltage specification requirement, thereby effectively saving the type and number of power supplies, and when detecting the backlight module, the test power supply device does not need to be frequently replaced, thereby effectively improving the production test efficiency.
Further, referring to fig. 4, in the present embodiment, two stages of voltage converting modules 21 are illustrated, and it can be understood that in other embodiments, the number of the voltage converting modules 21 may be increased according to the voltage requirement.
The boost unit 211 specifically includes a DC-DC control chip and a peripheral working circuit, and since the boost unit is an existing mature application circuit, the connection relationship and the working process of the boost unit are not described in detail in the present invention, in this embodiment, the DC-DC control chip may be a boost control chip with a model such as PF7900S of the linn corporation, LM3478 of the TI corporation, LM3486 of the li-lin corporation, NCV8870 of the ON corporation, or the like, and of course, in other embodiments, other control chips with the same function may also be used, which is not limited in this disclosure.
Each DC-DC control chip has a feedback network, i.e. FB feedback network, for setting the output voltage, and the output voltage can be set through the feedback network, so the present invention adjusts the output voltage of the boost unit 211 by adjusting the feedback signal, specifically, the voltage adjusting unit 212 includes a resistance setting subunit 2121, a sampling feedback subunit 2122, and a plurality of switch subunits 2123, wherein the plurality of switch subunits 2123 are connected to the resistance setting subunit 2121, each switch subunit 2123 is connected to a corresponding voltage adjustment instruction input terminal, and the feedback subunits are connected to the resistance setting subunit 2121 and the feedback pins of the DC-DC control chip, i.e. the FB _1 pin and the FB _2 pin. Each switch subunit 2123 is turned on or off according to the received voltage regulation instruction, so as to regulate the resistance value of the resistance setting subunit 2121, and then the sampling feedback subunit 2122 outputs a corresponding feedback signal to the voltage boosting unit 211 according to the resistance value of the current resistance setting subunit 2121.
That is, in the present invention, the output voltage of the voltage boost unit 211 is changed by adjusting the ground-to-ground value in the feedback network, and specifically, the resistance value of the resistance setting subunit 2121 can be flexibly adjusted by individually controlling the on or off of each switch subunit 2123, so that the sampling feedback subunit 2122 samples to obtain a corresponding feedback signal and outputs the feedback signal to the DC-DC control chip, and further, the voltage boost unit 211 outputs a corresponding voltage, thereby adjusting the output voltage. The adjusting mode is flexible and various, so that the voltage requirements of different backlight light sources can be met, and the application range of the power supply device is widened.
Specifically, each switch subunit 2123 includes a first resistor R1, a second resistor R2, and a transistor Q1, one end of the first resistor R1 is connected to the voltage regulation command input end, and the other end of the first resistor R1 is connected to the base of the transistor Q1 and one end of the second resistor R2; the other end of the second resistor R2 is connected with the emitter of the triode Q1 and the ground; the collector of the transistor Q1 is connected to the resistor setting subunit 2121. In this embodiment, the transistor Q1 is an NPN transistor Q1. As shown in fig. 4, the base of the transistor Q1 in each switch subunit 2123 is individually connected to a voltage adjustment command input terminal, and independently receives a corresponding switch adjustment signal, as shown in the figures, ON/OFF-1, ON/OFF-2, and ON/OFF-n, the respective independent switch adjustment signal is divided by the first resistor R1 and the second resistor R2 and then input to the base of the transistor Q1, and the ON/OFF of each transistor Q1 is individually adjusted, so as to flexibly adjust the resistance of the resistor setting subunit 2121.
Further, the resistance setting subunit 2121 includes a ground resistor R0 and a plurality of third resistors R3 whose number is equal to that of the switch subunits 2123, wherein one end of each of the third resistors R3 is connected to one end of the ground resistor R0 and the sampling feedback subunit 2122, and the other end of each of the third resistors R3 is correspondingly connected to one switch subunit 2123, specifically to the collector of the transistor Q1. That is, in the voltage adjusting unit 212, all the third resistors R3 and the ground resistor R0 are connected in parallel, and the collector of each triode Q1 is correspondingly connected to one third resistor R3, and whether the third resistor R3 connected to the triode Q1 is connected to a circuit is controlled by controlling the on/off of the triode Q1, so as to adjust the resistance value of the resistor setting subunit 2121, that is, the ground resistance value of the feedback network, and achieve the purpose of changing the output voltage.
Furthermore, the sampling feedback subunit 2122 includes a sampling resistor Rs, one end of the sampling resistor Rs is connected to the resistor setting subunit 2121, specifically to one end of the ground resistor R0, the other end of the sampling resistor Rs is connected to the feedback end of the voltage boosting unit 211, after the number of the third resistors R3 in the access circuit is set so as to adjust the ground value, a corresponding feedback signal is collected and fed back to the voltage boosting unit 211 through the sampling resistor Rs according to the current ground value, specifically, a feedback voltage signal is collected to the voltage boosting unit 211, and the voltage boosting unit 211 outputs a corresponding voltage according to the feedback signal, so as to adjust the output voltage.
Based on the power supply device, the invention also provides a multi-stage DC-DC converter, which is not described in detail since the multi-stage DC-DC converter is described in detail above.
Based on the above power supply device, the present invention also provides a display device, including a backlight source and the power supply device as described above, which is not described in detail since it has been described in detail above.
In order to better understand the voltage regulation process of the multi-stage DC-DC converter provided by the present invention, the voltage regulation process of the multi-stage DC-DC converter is described below with reference to fig. 4 by way of an application example:
as shown in fig. 4, the base of each transistor in the two-stage voltage conversion module is individually connected to a voltage adjustment command input terminal, and independently receives corresponding switching adjustment signals, as shown in the figures, ON/OFF-1, ON/OFF-2, and ON/OFF-n, and the collector of each transistor is correspondingly connected to a third resistor, and all the third resistors are connected in parallel with the ground resistor. When the output voltage is regulated, each triode receives a voltage regulation instruction, namely a switch regulation signal, for example, high level signals are input into ON/OFF-1 and ON/OFF-2, low level signals are input into the other voltage regulation instruction input ends, the triodes connected with the signal ends of ON/OFF-1 and ON/OFF-2 are conducted at the moment, the other triodes are all cut OFF, two third resistors in the resistor setting subunit are connected with the ground resistor in parallel, the current ground resistance of the two-stage voltage conversion module, namely the downward bias resistors of FB-1-1 and FB-2-2 in the figure, and the sampling resistor collects corresponding feedback voltage and feeds the feedback voltage back to the DC-DC control chip, so that the output voltage of the boosting unit is regulated, and the effect of changing the output voltage is achieved.
Specifically, when the output voltage needs to be increased, the ground resistance value is controlled to be decreased, a mode of connecting more third resistors in parallel can be adopted, or selection is performed according to the resistance values of the third resistors of different branches, similarly, when the output voltage needs to be decreased, the ground resistance value is controlled to be increased, a mode of reducing the parallel connection number of the third resistors can be correspondingly adopted, or selection is performed according to the resistance values of the third resistors of different branches, and the selection can be specifically performed according to actual requirements.
In summary, in the multi-stage DC-DC converter, the power supply apparatus and the display device provided by the present invention, the multi-stage DC-DC converter is connected to the power supply converter and the backlight light source, and includes N stages of voltage converting modules connected in series, where N is greater than or equal to 2; the first-stage voltage conversion module receives the direct-current voltage output by the power converter, converts the direct-current voltage into a first voltage and outputs the first voltage to the second-stage voltage conversion module, the second-stage voltage conversion module continues to perform voltage conversion on the first voltage and outputs a second voltage, and the like. The output voltage of the DC-DC converter can be flexibly adjusted through step-by-step voltage conversion so as to meet the voltage specification requirements of different backlight sources, improve the compatibility of the power supply device and effectively improve the production test efficiency of the display module.
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 (6)
1. A multi-stage DC-DC converter is connected with a power converter and a backlight light source and is characterized by comprising N stages of voltage conversion modules which are connected in series, wherein N is more than or equal to 2; the first-stage voltage conversion module receives the direct-current voltage output by the power converter, converts the direct-current voltage into a first voltage and outputs the first voltage to the second-stage voltage conversion module, the second-stage voltage conversion module continues to perform voltage conversion on the first voltage and outputs a second voltage, and so on, after each stage of voltage conversion module is controlled to perform voltage conversion in sequence, the Nth-stage voltage conversion module outputs a preset power supply voltage to the backlight light source;
each voltage conversion module comprises a boosting unit and a voltage regulation unit, the voltage regulation unit outputs a corresponding feedback signal to the boosting unit according to a received voltage regulation instruction, the boosting unit receives the A-1 voltage output by the previous-stage voltage conversion module, converts the A-1 voltage into the A voltage according to the feedback signal and outputs the A voltage to the next-stage voltage conversion module; wherein A is the stage number of the current voltage conversion module;
the output voltage of the boosting unit is regulated by the voltage regulating unit in each level of voltage conversion module;
the voltage regulating unit comprises a resistance setting subunit, a sampling feedback subunit and a plurality of switch subunits, each switch subunit is turned on or turned off according to a received voltage regulating instruction to regulate the resistance value of the resistance setting subunit, and the sampling feedback subunit outputs a corresponding feedback signal to the boosting unit according to the resistance value of the current resistance setting subunit;
each switch subunit comprises a first resistor, a second resistor and a triode, wherein one end of the first resistor is connected with the input end of a voltage regulation instruction, and the other end of the first resistor is connected with the base electrode of the triode and one end of the second resistor; the other end of the second resistor is connected with an emitting electrode of the triode and the ground; the collector of the triode is connected with the resistance setting subunit;
the resistance setting subunit comprises a ground resistance and a plurality of third resistances, the number of the third resistances is equal to that of the switch subunits, one end of each third resistance is connected with one end of the ground resistance and the sampling feedback subunit, and the other end of each third resistance is correspondingly connected with one switch subunit;
the sampling feedback subunit is connected with the resistance setting subunit and a feedback pin of the DC-DC control chip;
the resistance value of the resistance setting subunit is flexibly adjusted by independently controlling the on or off of each switch subunit, so that the sampling feedback subunit samples to obtain a corresponding feedback signal and outputs the feedback signal to the DC-DC control chip.
2. The multi-stage DC-DC converter according to claim 1,
when A is equal to 1, the boosting unit receives the direct-current voltage output by the power converter, converts the direct-current voltage into a first voltage according to the feedback signal and outputs the first voltage to the second-stage voltage conversion module;
and when A is equal to N, the boosting unit receives the N-1 voltage output by the N-1 level voltage conversion module, outputs the N-1 voltage as a preset power supply voltage according to the feedback signal and then outputs the preset power supply voltage to the backlight light source.
3. The multi-stage DC-DC converter according to claim 1, wherein the sampling feedback sub-unit comprises a sampling resistor, one end of the sampling resistor is connected with the resistor setting sub-unit, and the other end of the sampling resistor is connected with the feedback end of the boosting unit.
4. The multi-stage DC-DC converter according to claim 1, wherein the transistor is an NPN transistor.
5. A power supply device, comprising a housing, a PCB board disposed in the housing, a power converter disposed on the PCB board, wherein the PCB board is further disposed with a multi-stage DC-DC converter according to any one of claims 1-4, the power converter converts an AC input voltage into a DC voltage and outputs the DC voltage to the multi-stage DC-DC converter, and the multi-stage DC-DC converter performs a step-by-step voltage conversion on the DC voltage and outputs a predetermined supply voltage to a backlight source.
6. A display device comprising a backlight source, characterized in that it further comprises a power supply device as claimed in claim 5, the backlight source being supplied with power by said power supply device.
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| CN102055328A (en) * | 2009-10-30 | 2011-05-11 | 三星电机株式会社 | Multi-stage power supply |
| JP2016158385A (en) * | 2015-02-24 | 2016-09-01 | コニカミノルタ株式会社 | Power supply controller and image forming apparatus |
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| CN102055328A (en) * | 2009-10-30 | 2011-05-11 | 三星电机株式会社 | Multi-stage power supply |
| JP2016158385A (en) * | 2015-02-24 | 2016-09-01 | コニカミノルタ株式会社 | Power supply controller and image forming apparatus |
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