CN106059282A - Device for reducing audio noise of added, refitted and separated on-board audio-visual devices - Google Patents
Device for reducing audio noise of added, refitted and separated on-board audio-visual devices Download PDFInfo
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- CN106059282A CN106059282A CN201610392202.4A CN201610392202A CN106059282A CN 106059282 A CN106059282 A CN 106059282A CN 201610392202 A CN201610392202 A CN 201610392202A CN 106059282 A CN106059282 A CN 106059282A
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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
- H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
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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
- H02M3/33507—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 with automatic control of the output voltage or current, e.g. flyback converters
- H02M3/33523—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 with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
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- Electromagnetism (AREA)
- Dc-Dc Converters (AREA)
Abstract
This invention discloses a device for reducing audio noise of added, refitted and separated on-board audio-visual devices. The device comprises a power supply circuit, an overcurrent low-voltage protection circuit, a feedback circuit and a rectifying circuit; the power supply circuit uses an isolated DC-DC (Direct Current) power supply in the on-board audio-visual device, and uses an isolation transformer to isolate a primary power supply and a secondary power supply in the isolated DC-DC power supply; the power supply circuit is connected with the overcurrent low-voltage protection circuit and the rectifying circuit; the rectifying circuit is connected with the feedback circuit; the feedback circuit is connected with the overcurrent low-voltage protection circuit; and the feedback circuit adopts an optocoupler to isolate the feedback between the primary power supply and the secondary power supply. The device is applicable to the added, refitted and separated on-board audio-visual devices, and provides a method for reducing audio outputting noise of added, refitted and separated on-board audio-visual devices; and thus, users can perfectly enjoy the audio shock brought by added, refitted and separated on-board audio-visual devices rather than the noise.
Description
Technical field
The present invention relates to vehicle carried video equipment technical field, be specifically related to a kind of reduction and install additional and reequip and the vehicle-mounted shadow of split
The device of sound equipment audio noise.
Background technology
Along with popularizing of vehicle carried video equipment, carry out audio-visual devices onboard and install repacking additional or upgrade increasing, but
Owing to being to install repacking or upgrading additional, particularly retain the audio-visual devices of former car when increase function simultaneously, can bring about one
Problem greatly, is also to perplex a lot of car owners and the problem in 4S shop, and it is the poorest that this problem is exactly the effect of sound, mainly groans
The noise of the backgrounds such as sound, V-V sound, S-S sound.Individually testing former vehicle device, no problem, individually test additional equipment is not the most asked
Topic, both fit together the problem of having occurred as soon as.
The particularity powered due to automobile power source, all devices in automobile is all supplied by same power supply, different
Re-supply to each electrical equipment after household electrical source is all by transformer isolation blood pressure lowering.On car, the power supply of each equipment and ground are all
It is public, owing to each audio frequency apparatus can be linked together by power line and tone frequency channel wire, so loop can be produced, in nothing
As long as loop is equal to be coil (being exactly briefly antenna) in line electricity principle, that has been equal to an antenna and has ceaselessly connect
The interference signal that the electromotor that returns the vehicle to the garage and knock off interior, oil pump, apparatus such as computer produce, after being amplified by power amplifier, people are unacceptable,
The noise particularly issued after automobile starting.
Automobile audio install additional and reequip and in split noise elimination and lower be all particularly important, solve noise ask
During topic, ground connection is a particularly important problem.
Ground is on very close terms with electricity (signal).Ground connection, it is common that refer to be connected with the earth with conductor.Can be in electronic technology
Ground, may just with the earth wide of the mark, it is an equipotential plane in circuit.Ground in Source Music, television set, only
It it is a reference point of potential in receiver transmission line.Ground connection, is requisite in electronic technology.By the effect of ground connection, can
It is divided into working earthing, protective grounding, overvoltage protection ground connection, anti-static grounding, bonding, signal ground etc. multiple.In broadcasting and TV skill
In art, above several earthing types all can run into.
Protective grounding is that simple method is in order to prevent electric power polarity from connecing the anti-protection device causing device damage and arranging
Input at power supply adds backward diode over the ground, especially common in automobile audio equipment circuit.
Overvoltage protection ground connection is the earth protective device arranged for high-tension electricity.Lower pilot spark device most widely used
Be pressure-sensitive diode and neon bulb.Absorbed by ground connection and amplitude limit.Equipment power input has mu balanced circuit, also is provided with simultaneously
Overvoltage crowbar and current foldback circuit, and temperature protection circuit.
Shielding ground be for prevent electromagnetic induction and to depending on, tone frequency channel wire shield metal sheath, the metal shell of electronic equipment,
Radome, the metallic shield net (as surveyed the screened room of the index such as sensitivity, selectivity) of building carry out a kind of protection of ground connection
Measure.In all ground connection, shielding ground is the most complicated.Because shielding itself both can anti-external interference, again may by it reduce
The interference constituted to external world, and in equipment between each components and parts also must anti-electromagnetic interference, such as known middle week shell, electricity
Sub-tube shield cover is exactly example.
Holding wire bonding is particularly significant.Shielding bad, the improper meeting of ground connection and cause interference, these interference mainly have: 1.
AC influence, this is mainly caused by alternating current power supply.Protection to AC influence, is generally filtered power supply or adds at holding wire
Screen layer ground connection.Outside big stray EM field, carry out bonding for anti-electromagnetic interference the most necessary.Such as, electromotor
The interference of electromagnetic field will be produced, also can be by being sent to equipment inside electric wire, filtering and bonding, solve this problem.
2. High-frequency Interference.This kind of interference from the frequency conversion of all kinds of wireless transmitting stations or super-frequency-conversion signal, they scurry into after electronic equipment
Obtain improper demodulation in machine and form audio frequency interference.Such as plug ignition, relay contact spark.
Frequency is the highest, the most easily produces kelvin effect, and the wire netting eyelet of equipment just should be the least, the volume of holding wire screen layer
Knitting just should be the closeest, otherwise will lose shielding action.Holding wire to frequent plug, should prevent screen layer from loosening at plug and de-
Fall.The shielding of cause instrument and equipment sometimes is (they are linked up by plugs and sockets) that the shielding by holding wire enters ground, if
Shielding comes off, then easily cause interference.As relevant with interference in holding wire putting position, sometimes contact holding wire screen layer with hands
Interference is just that high-frequency signal interference is formed caused by distribution capacity coupling without, explanation.
Various electronic circuits have a reference potential point, and this reference potential point is exactly signal ground.Its effect is to protect
Card circuit has a unified reference potential, is unlikely to float and cause signal errors.The connection of signal ground is: same equipment
Signal input ground can not connect together with signal output ground, and should separate；The output ground of prime (equipment) only (sets with rear class
Standby) input ground be connected.Otherwise, signal may form feedback by ground wire, causes the floating of signal.This is in the test of equipment
In, the connection of signal ground especially to arouse attention.Such as, holding wire crust breaks bonding and produces noise, the most just belongs to and writes
Number by ground feedback make result inconsistent.Also the power amplifier shell having can not be directly grounded, and the point of all such ground connection is set to not
Ground connection, this noise phenomena just without.
Protective grounding and overvoltage protection ground connection are not the key points solving noise, and bonding and signal ground are only solution
The key point of noise.In addition, the also special ground connection of automobile audio.Many vehicles installing power amplifier, are broadcasting amplification of volume
(being not above normal electricity consumption amount) during bass, instrument panel lamp can flash with music, this is because only by the electrode line overstriking of power amplifier
Have ignored negative line, the formation of circuit is intended to loop from positive to negative, and in the case of negative pole is thin, positive pole slightly also cannot increase again
Electric current, as in the case of water pipe thickness inequality the flow of water only in thin water pipe flow.So the electricity of negative pole to be strengthened
Flow, specific practice is: a negative line (electromotor and vehicle body are insulation) of electromotor to battery and electromotor are to car
The thickness of one negative line of body is minimum will be as electrode line.
By above principle analysis it can be seen that the noise problem of 80% can by " " go solve, such as one
Point ground connection, add the width of the earth, the segmentation etc. on ground, but install additional and reequip and split partial circuit sometimes is to be not belonging to technology people
Member can control, and how solving this problem becomes an important topic of this area.
Summary of the invention
It is an object of the invention to provide a kind of reduction install additional and reequip and the dress of split vehicle carried video equipment audio noise
Putting, main inventive concept is to install additional and reequip and during the environment division of split by isolating the side of DC-DC power source making
Formula goes the noise problem brought with solving power supply.
For achieving the above object, reduction of the present invention is installed additional and reequips and split vehicle carried video equipment audio noise
Device includes power supply circuits, crosses stream low-voltage protection circuit, feedback circuit and rectification circuit, and described power supply circuits are at vehicle carried video
Equipment uses isolation DC-DC power source, and uses isolating transformer by primary source and secondary electrical in isolation DC-DC power source
Source isolates；Described power supply circuits are connected with stream low-voltage protection circuit and rectification circuit excessively, rectification circuit and feedback circuit
Connecting, feedback circuit is connected with crossing stream low-voltage protection circuit；Described feedback circuit uses light-coupled isolation primary source and secondary
Feedback between power supply.
Described DC-DC power source includes two kinds of input powers of 12V and 24V.
Described reduction is installed additional and reequips and the device of split vehicle carried video equipment audio noise is applicable to vehicle-mounted product
Reequiping and install additional, described vehicle-mounted product includes MP3, MP5, DVD, navigation and systematic multimedia.
Described power supply circuits include that input power, input power are connected with the former limit Same Name of Ends of isolating transformer, the 3rd
One end of electric capacity, the 4th electric capacity, the second resistance, the 3rd resistance and the second electric capacity is both connected to input power and isolating transformer
Between；The ground of primary source is accessed after 3rd electric capacity and the 4th electric capacity parallel connection；At the beginning of accessing after second resistant series the 11st electric capacity
The ground of level power supply；Second electric capacity and the second Diode series, an end of the 3rd resistance be connected on the second electric capacity and the second diode it
Between；Second diode is connected with the drain electrode of switching tube；The former limit non-same polarity of isolating transformer is connected to the second diode and opens
Closing between the drain electrode of pipe, the 6th pin of integrated off-line type switching regulator is connected between the second resistance and the 11st electric capacity.
Described stream low-voltage protection circuit of crossing includes the tenth resistance, the source electrode of one end connecting valve pipe of the tenth resistance,
The other end of the tenth resistance accesses the ground of primary source；One end of 8th resistance be connected to the tenth resistance and switching tube source electrode it
Between, access the ground of primary source after other end series connection the 12nd electric capacity of the 8th resistance；The of integrated off-line type switching regulator
Three-prong is connected between the 8th resistance and the 12nd electric capacity；7th resistance, the 11st resistance and one end of the 3rd diode
Being all connected to the grid of switching tube, the other end of the 7th resistance is connected between the tenth resistance and the source electrode of switching tube；11st
The 5th pin of integrated off-line type switching regulator is accessed after resistance and the 3rd diodes in parallel；Tenth electric capacity be connected to integrated from
Between first pin and the 4th pin of wire type switching regulator, the 4th pin also accesses the ground of primary source.
Described feedback circuit includes optocoupler and precision voltage regulator, and the input diode anode of optocoupler and the 4th resistance are even
Connecing, the input diode negative terminal of optocoupler is connected with the negative electrode of precision voltage regulator；6th resistance is connected to the input diode of optocoupler
Between anode and input diode negative terminal；5th resistance and the 4th resistor coupled in parallel, the 5th resistance and the 12nd resistant series；8th
Electric capacity one end is connected between the input diode negative terminal of optocoupler and the 6th resistance, the other end of the 8th electric capacity and the one of the 9th resistance
End connects, and the other end of the 9th resistance is connected between the 5th resistance and the 12nd resistance；One end of 9th electric capacity is connected to light
Between input diode negative terminal and the negative electrode of precision voltage regulator of coupling, the other end of the 9th electric capacity is connected to the 5th resistance and the tenth
Between two resistance；The reference edge of precision voltage regulator is connected between the 5th resistance and the 12nd resistance；The anode of precision voltage regulator
With the ground that the 12nd resistance all accesses secondary power；13rd electric capacity is connected to the emitter terminal driving audion and the collection of optocoupler
Between electrode tip, the emitter terminal driving audion of optocoupler accesses the ground of primary source；Integrated off-line type switching regulator
Second pin is connected between the collector terminal and the 13rd electric capacity that drive audion of optocoupler.
Described optocoupler uses linear optical coupling PC817, and the model of described precision voltage regulator is TL431.
The ground of described primary source is different from the ground of secondary power.
Described rectification circuit includes the first diode, and the secondary that one end of the first diode connects isolating transformer is of the same name
End connects, and the other end of the first diode connects respectively with the first resistance and the 5th electric capacity, the first resistance and the first capacitances in series,
First electric capacity is connected between the secondary Same Name of Ends of isolating transformer and the first diode；5th electric capacity and the 6th electric capacity and the 7th
The secondary non-same polarity of isolating transformer is accessed after electric capacity parallel connection；6th electric capacity and the 7th electric capacity, the first resistance and the 4th electricity
Resistance and the 5th resistance are all connected to power output end；The secondary non-same polarity of isolating transformer also accesses the ground of secondary power.
Present invention have the advantage that reduction of the present invention is installed additional and reequips and split vehicle carried video equipment audio frequency is made an uproar
The device of sound is compared with prior art, it is adaptable to installs additional and reequips and split vehicle carried video equipment, it is provided that reduces and installs additional and change
The method of the vehicle carried video equipment audio frequency output noise after dress and split, allows users to perfectly enjoy by installing additional and changing
The audio frequency that dress and split bring shakes rather than noise.
Accompanying drawing explanation
Fig. 1 is DC-DC circuit structural representation of the prior art.
Fig. 2 is that reduction of the present invention is installed additional and reequips and the circuit of device of split vehicle carried video equipment audio noise
Structural representation.
Fig. 3 is the application schematic diagram in installing vehicle carried video equipment additional of the circuit shown in Fig. 2.
Detailed description of the invention
Following example are used for illustrating the present invention, but are not limited to the scope of the present invention.
Fig. 1 is conventional use of DC-DC circuit in prior art, its simple in construction, and the ground of its primary and secondary is phase
Lead to.The structure Application comparison of this circuit is extensive, is not required to repeat.
Fig. 2 is that reduction of the present invention is installed additional and reequips and the circuit of device of split vehicle carried video equipment audio noise
Structural representation.Reduction of the present invention is installed additional and reequips and the device of split vehicle carried video equipment audio noise includes power supply
Circuit, cross stream low-voltage protection circuit, feedback circuit and rectification circuit, described power supply circuits use in vehicle carried video equipment every
From DC-DC power source, and use in isolation DC-DC power source isolating transformer T1 primary source and secondary power carried out every
From；Described power supply circuits are connected with stream low-voltage protection circuit and rectification circuit excessively, and rectification circuit is connected with feedback circuit, feedback
Circuit is connected with crossing stream low-voltage protection circuit；Described feedback circuit uses between optocoupler U1 isolation primary source and secondary power
Feedback.
Described DC-DC power source includes that (this 12V refers to that gasoline car is supplied to the nominal voltage of mobile unit, typically to 12V
At 9V-15.6V) and 24V (this 24V refers to that diesel vehicle is supplied to the nominal voltage of mobile unit, be usually at 18V-
31.2V) two kinds of input powers.
Described reduction is installed additional and reequips and the device of split vehicle carried video equipment audio noise is applicable to vehicle-mounted product
Reequiping and install additional, described vehicle-mounted product includes MP3, MP5, DVD, navigation and systematic multimedia.This device employ every
From transformator and optocoupler, described isolating transformer includes various different profile, winding type, topological structure, all can use；
Described optocoupler includes various different profile and model, all can use.
As in figure 2 it is shown, described power supply circuits include input power DCIN1, input power DCIN1 and isolating transformer T1
Former limit Same Name of Ends connect, the 3rd electric capacity C3, the 4th electric capacity C4, the second resistance R2, the 3rd resistance R3 and the second electric capacity C2's
One end is both connected between input power DCIN1 and isolating transformer T1；Access after 3rd electric capacity C3 and the 4th electric capacity C4 parallel connection
The ground HGND of primary source；The ground of primary source is accessed after second resistance R2 series connection the 11st electric capacity C11；Second electric capacity C2 and
Two diode D2 series connection, an end of the 3rd resistance R3 is connected between the second electric capacity C2 and the second diode D2；Second diode D2
It is connected with the drain D of switching tube Q1；The former limit non-same polarity of isolating transformer T1 is connected to the second diode D2 and switching tube Q1
Drain D between, the 6th pin 6 of integrated off-line type switching regulator U2 is connected to the second resistance R2 and the 11st electric capacity C11
Between.
Described power supply circuits provide the DC voltage of 12V or 24V filtered through the 3rd electric capacity C3 and the 4th electric capacity C4,
This DC voltage gives the 11st electric capacity C11 charging through the second resistance R2, when the voltage of the 11st electric capacity C11 reaches integrated off-line type
During the startup voltage threshold of switching regulator U2, integrated off-line type switching regulator U2 starts working and provides driving pulse, by
5th pin 5 exports the work of pull switch pipe.The selection of integrated off-line type switching regulator U2 is it is noted that it starts voltage and work
Making voltage will be in the range of 12V or 24V, in order to avoid impact starts and work.
Described crosses one end connecting valve pipe Q1 that stream low-voltage protection circuit includes the tenth resistance R10, the tenth resistance R10
Source S, the other end of the tenth resistance R10 accesses the ground of primary source；One end of 8th resistance R8 is connected to the tenth resistance R10
And between the source electrode of switching tube Q1, after other end series connection the 12nd electric capacity C12 of the 8th resistance R8, access the ground of primary source；Collection
The three-prong 3 becoming off-line type switching regulator U2 is connected between the 8th resistance R8 and the 12nd electric capacity C12；7th resistance 7,
One end of 11st resistance R11 and the 3rd diode D3 is all connected to the grid G of switching tube Q1, the other end of the 7th resistance 7
It is connected between the tenth resistance R10 and the source electrode of switching tube Q1；Access set after 11st resistance R11 and the 3rd diode D3 parallel connection
Become the 5th pin 5 of off-line type switching regulator U2；Tenth electric capacity C10 is connected to the first of integrated off-line type switching regulator U2
Between pin 1 and the 4th pin 4, the 4th pin 4 also accesses the ground of primary source.
Described stream low-voltage protection circuit of crossing is also called short circuit overcurrent, under-voltage protecting circuit.Shakiness due to input voltage
Fixed, or some other extrinsic factor, sometimes result in circuit and occur short-circuit, under-voltage etc. being unfavorable for that the phenomenon that circuit works is sent out
Raw, therefore, circuit must have certain defencive function.As in figure 2 it is shown, if owing to certain reason, outfan is short-circuit and produces
Giving birth to stream, the electric current of the drain D of switching tube Q1 will significantly rise, and the voltage at the tenth resistance R10 two ends rises, integrated off-line type
Voltage on the three-prong 3 of switching regulator U2 also rises.When the voltage of this three-prong 3 exceedes normal value, integrated from
6th pin 6 of wire type switching regulator U2 is without output, and switching tube Q1 (metal-oxide-semiconductor) ends, it is achieved thereby that overcurrent protection.If
Voltage is less than normal voltage, and the 6th pin 6 voltage of integrated off-line type switching regulator U2 also declines, when the electricity dropping to regulation
When pressure is following, integrated off-line type switching regulator U2 closes output, plays the effect of low-voltage variation.
Described feedback circuit includes optocoupler U1 and precision voltage regulator U3, the input diode anode of optocoupler U1 and the 4th electricity
Resistance R4 connects, and the input diode negative terminal of optocoupler U1 is connected with the negative electrode of precision voltage regulator U3；6th resistance R6 is connected to optocoupler
Between input diode anode and the input diode negative terminal of U1；5th resistance R5 and the 4th resistance R4 is in parallel, the 5th resistance R5
Connect with the 12nd resistance R12；8th electric capacity C8 mono-end is connected between the input diode negative terminal of optocoupler U1 and the 6th resistance R6,
One end of the other end of the 8th electric capacity C8 and the 9th resistance R9 connects, the other end of the 9th resistance R9 be connected to the 5th resistance R5 with
Between 12nd resistance R12；One end of 9th electric capacity C9 is connected to input diode negative terminal and the precision voltage regulator U3 of optocoupler U1
Negative electrode between, the other end of the 9th electric capacity C9 is connected between the 5th resistance R5 and the 12nd resistance R12；Precision voltage regulator U3
Reference edge be connected between the 5th resistance R5 and the 12nd resistance R12；The anode of precision voltage regulator U3 and the 12nd resistance R12
All access the ground GND of secondary power；13rd electric capacity C13 is connected to the emitter terminal driving audion and the colelctor electrode of optocoupler U1
Between end, the emitter terminal driving audion of optocoupler U1 accesses the ground of primary source；Integrated off-line type switching regulator U2's
Second pin 2 is connected between the collector terminal and the 13rd electric capacity C13 that drive audion of optocoupler U1.
Described optocoupler U1 uses linear optical coupling PC817, and the model of described precision voltage regulator U3 is TL431.
The ground of described primary source is different from the ground of secondary power.The ground of primary source is the ground of power supply, secondary power
Ground be signal ground (i.e. the ground of audio-video signal).
Described feedback circuit uses precision voltage regulator TL431 and linear optical coupling PC817.Utilize precision voltage regulator TL43l
Adjustable precise manostat constitutes error voltage amplifier, then is adjusted output accurately by linear optical coupling.Such as Fig. 2 institute
Showing, the 12nd resistance R12, the 5th resistance R5 are the external control resistance of precision voltage regulator, and they determine the height of output voltage,
External error amplifier is formed in the lump with precision voltage regulator TL431.When output voltage DCOUT raises, cause that to arrange voltage big
In reference voltage (reference voltage of precision voltage regulator TL431 is 2.5V), make error amplifier in precision voltage regulator TL431
Output voltage raises, and drives the output voltage of audion to reduce, also make output voltage DCOUT in causing precision voltage regulator TL431
Declining, last DCOUT tends towards stability；Otherwise, output voltage declines to cause and arranges voltage and decline, when output voltage is less than arranging electricity
During pressure, the output voltage of error amplifier declines, and the output voltage driving audion in precision voltage regulator TL431 raises,
The compensation input current making second pin 2 of integrated off-line type switching regulator U2 eventually changes therewith, promotes integrated off-line type
In switching regulator U2 sheet, PWM comparator is adjusted, changes dutycycle, reach the purpose of voltage stabilizing.
Described rectification circuit includes that one end of the first diode D1, the first diode D1 connects the pair of isolating transformer T1
Limit Same Name of Ends connects, and the other end and the first resistance R1 and the 5th electric capacity C5 of the first diode D1 connect respectively, the first resistance R1
Connecting with the first electric capacity C1, the first electric capacity C1 is connected between the secondary Same Name of Ends of isolating transformer T1 and the first diode D1；
The secondary non-same polarity of isolating transformer T1 is accessed after 5th electric capacity C5 and the 6th electric capacity C6 and the 7th electric capacity C7 parallel connection；6th electricity
Hold C6 and the 7th electric capacity C7, the first resistance R1 and the 4th resistance R4 and the 5th resistance R5 and be all connected to power output end；Isolation
The secondary non-same polarity of transformator T1 also accesses the ground of secondary power.
Described rectification circuit is also called current rectifying and wave filtering circuit, and current rectifying and wave filtering circuit directly influences the big of ripple voltage
Little, affect the performance of output voltage.Affect switched power output ripple amplitude mainly has the following aspects:
(1) noise of input power, refers to the alternating component included in input power.The scheme solved is defeated at power supply
Enter end and strengthen the 4th electric capacity C4 (input of π shape filtering can also be become at input) to filter this noise jamming.
(2) high-frequency signal noise, carries out the copped wave of high frequency, then by the transformation of high frequency to direct current input in Switching Power Supply
Device is transmitted, and in this process, will necessarily mix the noise jamming of high frequency, and also power tube device is during switch
The high-frequency noise caused.Solution for this kind of high-frequency noise is the mode using the filtering of π type at outfan.Filter inductance
Use the inductance of 150 μ H, high-frequency noise can be filtered, (Fig. 2 does not show).
(3) fast recovery diode (the first diode D1) is used to carry out rectification.Based on low pressure, electric current low in energy consumption, big
Feature, is conducive to improving the efficiency of power supply, and its reverse recovery time is short, advantageously reduces high-frequency noise.
(4) commutation diode parallel connection RC reduces peak voltage.
In powerful rectification circuit, there is bigger stray inductance in secondary commutation bridge circuit, output rectifier tube is in the change of current
Time, owing to there is unwanted oscillation in circuit, rectifier tube can bear bigger peak voltage, and the existence of peak voltage improves whole
The resistance to pressure request of stream diode, also will bring extra circuit loss.Countermeasure is to add RCD at the former avris of isolating transformer T1 to delay
Rush circuit；Secondary side commutation diode parallel connection RC, reduces peak voltage.
Use reduction of the present invention to install additional and reequip and when the device of split vehicle carried video equipment audio noise
Should be noted that herein below:
1., due to the difference needed, the output voltage of insulating power supply (isolating transformer) is different, can set on demand
Fixed.Additional equipment generally uses 5V and powers and more can directly export DC5V, it is also possible to output 12V or other voltage；
2. the ground of the power supply of input and the ground of output need separately, and at least two ground of equipment end at rear dress can not directly connect
Together；
3. the ground of the shell ground input power to be connected to of entire machine, with audio frequency and video isolate in equipment end；
4. being careful when using terminal, the ground of terminal can not be connected with shell；
5. the power consumption limit of the circuit of this device is within 30W, even has only to 2W (as MP3 broadcasts according to different equipment
Put device) the most much of that；
If 6. having communication with former car, audio frequency and video to be used ground, it is preferably formed with the most digitally；
The most do not provide the on/off circuit controlled by ACC.Because that not to be the present invention to be described is main for this
Content.
Fig. 3 shows the application schematic diagram in installing vehicle carried video equipment additional of the circuit shown in Fig. 2.In Fig. 3, D belongs to former
The stereo set of car；ABC is the audio-visual devices (function division, convenient narration) installed additional.A and B be power pack and completely every
From, C is functional module.Ground between so D equipment and A equipment has big electric current to flow, and is responsible for energy resource supply.D equipment sets with C
The transmission of video-audio signal is only had, the ground flowing between D and C equipment of the faintest electric current between Bei.The most permissible
Think that the ground of D equipment and C equipment is equipotential.Ground within B and C is that designer can control, by rational ground connection
Mode, the process on the ground such as the flow direction of signal, can be limited in interference in minimum scope.So overall noise is just controlled
In the range of.
Here repacking and install additional part (A, B, C) be probably MP3 (such as cigar lighter MP3, wired and be wirelessly transferred audio frequency),
MP5, DVD, navigation etc., include but not limited to above listed equipment.
Although, the present invention is described in detail to have used general explanation and specific embodiment, but at this
On the basis of invention, can make some modifications or improvements it, this will be apparent to those skilled in the art.Therefore,
These modifications or improvements without departing from theon the basis of the spirit of the present invention, belong to the scope of protection of present invention.
Claims (9)
1. a reduction is installed additional and reequips and the device of split vehicle carried video equipment audio noise, it is characterised in that described device
Including power supply circuits, crossing stream low-voltage protection circuit, feedback circuit and rectification circuit, described power supply circuits are at vehicle carried video equipment
The middle isolation DC-DC power source that uses, and use isolating transformer primary source and secondary power to be entered in isolation DC-DC power source
Row isolation；Described power supply circuits are connected with stream low-voltage protection circuit and rectification circuit excessively, and rectification circuit is connected with feedback circuit,
Feedback circuit is connected with crossing stream low-voltage protection circuit；Described feedback circuit use light-coupled isolation primary source and secondary power it
Between feedback.
2. device as claimed in claim 1, it is characterised in that described DC-DC power source includes 12V and 24V two kinds input electricity
Source.
3. device as claimed in claim 2, it is characterised in that described device is applicable to the repacking of vehicle-mounted product and installs additional, institute
State vehicle-mounted product and include MP3, MP5, DVD, navigation and systematic multimedia.
4. device as claimed in claim 3, it is characterised in that described power supply circuits include input power, input power with
The former limit Same Name of Ends of isolating transformer connects, the 3rd electric capacity, the 4th electric capacity, the second resistance, the 3rd resistance and the second electric capacity
One end is both connected between input power and isolating transformer；Primary source is accessed after 3rd electric capacity and the 4th electric capacity parallel connection
Ground；The ground of primary source is accessed after second resistant series the 11st electric capacity；Second electric capacity and the second Diode series, the 3rd resistance
An end be connected between the second electric capacity and the second diode；Second diode is connected with the drain electrode of switching tube；Isolating transformer
Former limit non-same polarity is connected between the second diode and the drain electrode of switching tube, the 6th pin of integrated off-line type switching regulator
It is connected between the second resistance and the 11st electric capacity.
5. device as claimed in claim 4, it is characterised in that described stream low-voltage protection circuit of crossing includes the tenth resistance, should
The source electrode of one end connecting valve pipe of the tenth resistance, the other end of the tenth resistance accesses the ground of primary source；The one of 8th resistance
End is connected between the tenth resistance and the source electrode of switching tube, accesses primary electrical after other end series connection the 12nd electric capacity of the 8th resistance
The ground in source；The three-prong of integrated off-line type switching regulator is connected between the 8th resistance and the 12nd electric capacity；7th resistance,
One end of 11st resistance and the 3rd diode is all connected to the grid of switching tube, and the other end of the 7th resistance is connected to the tenth
Between resistance and the source electrode of switching tube；Integrated off-line type switching regulator is accessed after 11st resistance and the 3rd diodes in parallel
5th pin；Tenth electric capacity is connected between the first pin and the 4th pin of integrated off-line type switching regulator, the 4th pin
Also access the ground of primary source.
6. device as claimed in claim 5, it is characterised in that described feedback circuit includes optocoupler and precision voltage regulator, light
The input diode anode of coupling and the 4th resistance connect, and the input diode negative terminal of optocoupler is connected with the negative electrode of precision voltage regulator；
6th resistance is connected between the input diode anode of optocoupler and input diode negative terminal；5th resistance and the 4th resistance are also
Connection, the 5th resistance and the 12nd resistant series；8th electric capacity one end be connected on the input diode negative terminal of optocoupler and the 6th resistance it
Between, the other end of the 8th electric capacity and one end of the 9th resistance connect, and the other end of the 9th resistance is connected to the 5th resistance and the tenth
Between two resistance；One end of 9th electric capacity is connected between input diode negative terminal and the negative electrode of precision voltage regulator of optocoupler, the
The other end of nine electric capacity is connected between the 5th resistance and the 12nd resistance；The reference edge of precision voltage regulator is connected to the 5th resistance
And between the 12nd resistance；The anode of precision voltage regulator and the 12nd resistance all access the ground of secondary power；13rd electric capacity is even
It is connected between the emitter terminal and the collector terminal that drive audion of optocoupler, at the beginning of the emitter terminal driving audion of optocoupler accesses
The ground of level power supply；Second pin of integrated off-line type switching regulator is connected to the collector terminal and the driving audion of optocoupler
Between 13 electric capacity.
7. device as claimed in claim 6, it is characterised in that described optocoupler uses linear optical coupling PC817, described precision
The model of source of stable pressure is TL431.
8. device as claimed in claim 7, it is characterised in that the ground of described primary source is different from the ground of secondary power.
9. device as claimed in claim 8, it is characterised in that described rectification circuit includes the first diode, the one or two pole
One end of pipe connects the secondary Same Name of Ends of isolating transformer and connects, the other end of the first diode and the first resistance and the 5th electric capacity
Connecting respectively, the first resistance and the first capacitances in series, the first electric capacity is connected to the secondary Same Name of Ends and the one or two of isolating transformer
Between the pipe of pole；The secondary non-same polarity of isolating transformer is accessed after 5th electric capacity and the 6th electric capacity and the 7th electric capacity parallel connection；6th
Electric capacity and the 7th electric capacity, the first resistance and the 4th resistance and the 5th resistance are all connected to power output end；Isolating transformer
Secondary non-same polarity also accesses the ground of secondary power.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610392202.4A CN106059282A (en) | 2016-06-03 | 2016-06-03 | Device for reducing audio noise of added, refitted and separated on-board audio-visual devices |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610392202.4A CN106059282A (en) | 2016-06-03 | 2016-06-03 | Device for reducing audio noise of added, refitted and separated on-board audio-visual devices |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN106059282A true CN106059282A (en) | 2016-10-26 |
Family
ID=57169466
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610392202.4A Pending CN106059282A (en) | 2016-06-03 | 2016-06-03 | Device for reducing audio noise of added, refitted and separated on-board audio-visual devices |
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| Country | Link |
|---|---|
| CN (1) | CN106059282A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111130337A (en) * | 2019-12-03 | 2020-05-08 | 浪潮金融信息技术有限公司 | Audio isolation noise reduction scheme based on power isolation |
| TWI715356B (en) * | 2019-12-16 | 2021-01-01 | 宏碁股份有限公司 | Power supply circuit capable of restting dc/ac lacth-off and related method |
-
2016
- 2016-06-03 CN CN201610392202.4A patent/CN106059282A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111130337A (en) * | 2019-12-03 | 2020-05-08 | 浪潮金融信息技术有限公司 | Audio isolation noise reduction scheme based on power isolation |
| TWI715356B (en) * | 2019-12-16 | 2021-01-01 | 宏碁股份有限公司 | Power supply circuit capable of restting dc/ac lacth-off and related method |
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Application publication date: 20161026 |
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