CN106161041B - A kind of power grade method of adjustment of receiving end equipment and receiving end equipment - Google Patents
A kind of power grade method of adjustment of receiving end equipment and receiving end equipment Download PDFInfo
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- CN106161041B CN106161041B CN201610580475.1A CN201610580475A CN106161041B CN 106161041 B CN106161041 B CN 106161041B CN 201610580475 A CN201610580475 A CN 201610580475A CN 106161041 B CN106161041 B CN 106161041B
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Abstract
The present invention discloses the power grade method of adjustment of a kind of receiving end equipment and receiving end equipment, and the PD includes: input terminal, PD module, load blocks, control module and detection resistance；PD module, for when the PSE transmits detection voltage, starting the work of control module and feeding back detection electric current to PSE by inverting input terminal；When PSE transmits operating voltage, the connection of closure and the load blocks is to start the load blocks；Detection resistance, between PD module and inverting input terminal, for working in detection-phase to feed back detection electric current to PSE；The control module, it is connect with first switch, detection electric current for feeding back in from inverting input terminal to PSE opens the first switch when being unsatisfactory for given threshold, with the resistance value of modulation detection resistance, the upward incompatible high-grade PD of the more caused PSE of power classification standard to solve the problem of POE system.
Description
Technical field
The present invention relates to local area network technology field more particularly to the power grades of a kind of receiving end equipment and receiving end equipment
Method of adjustment.
Background technique
POE (Power Over Ethernet, Power over Ethernet) refers to that being routed architecture in existing Ethernet does not make
In the case where any change, the technology of direct current supply can also be provided for equipment while transmitting data-signal.POE technology can be true
The normal operation for guaranteeing existing network while existing structure is routed safe is protected, reduces cost to the maximum extent.One complete
POE system include power supply end equipment (PSE, Power Sourcing Equipment) and receiving end equipment (PD, Powered
Device) two parts, wherein it is also the management of entire POE Power over Ethernet process that PSE device, which is while PD equipment is powered,
Person.
For POE system, PSE needs first to remove identification PD, determines the power grade of PD, and according to the power grade of PD
It is powered, and knows method for distinguishing, exactly apply certain voltage signal to PD, an identification resistance is had inside PD (no
With the PD of power, with different identification resistance), which is absorbed by electric current when being applied certain identification voltage,
PSE exports electric current after applying identification voltage, through measurement, to identify the PD of different capacity grade, here it is POE systems
The power classification function of system.
Since the power classification grade of POE system has very much, and different capacity grade belongs to various criterion, such as
Class0~class3 is the standard of 802.3af, and class 4 is the standard of 802.3at, and class 5 is customized standard.So
More grade scales, results in there are compatibility issue, although supporting high-grade PSE can be backward compatible and then identifying low
The PD of grade, but only the PSE of inferior grade is supported but to have no way upward-compatible high-grade PD.Such as: one is supported 802.3at's
PSE can only identify the PD of 0~class of class 4, when the grade of PD is class 5, will be identified as by PSE illegally
Equipment leads to not power.
To sum up, the power grade method of adjustment for needing a kind of PD is more to the power classification standard for solving POE system, leads
The PSE of cause upwards incompatible high-grade PD the problem of.
Summary of the invention
The embodiment of the present invention provides the power grade method of adjustment of a kind of power receiving equipment and power receiving equipment, to solve POE
The power classification standard of system is more, caused PSE upwards incompatible high-grade PD the problem of.
The method of the present invention includes a kind of receiving end equipment PD, and the PD includes: input terminal, PD module, load blocks, control
Module and detection resistance；The input terminal includes normal phase input end and inverting input terminal, and the normal phase input end is for receiving
The voltage that the end equipment PSE that powers is transmitted, the inverting input terminal are used to feed back detection electric current to the PSE；
The PD module, for starting the work of the control module and passing through institute when the PSE transmits detection voltage
It states inverting input terminal and feeds back detection electric current to the PSE；When the PSE transmits operating voltage, closure and the load blocks
Connection to start the load blocks；
The detection resistance, between the PD module and the inverting input terminal, for detection-phase work with
Detection electric current is fed back to the PSE, the detection resistance includes first resistor and second resistance in parallel；
The control module, including the first switch being connect with the second resistance, for the inverting input terminal to
The detection electric current of the PSE feedback is unsatisfactory for opening the first switch when given threshold, to modulate the resistance of the detection resistance
Value.
Based on same inventive concept, the embodiment of the present invention further provides the power of receiving end equipment PD a kind of
Level adjustment method, this method comprises:
The normal phase input end of the PD receive power supply end equipment PSE transmission the first detection cycle detection voltage when,
The PD module of the PD provides operating voltage for the detection resistance of the PD, and the control module control first switch of the PD is led
Logical, the resistance value of the detection resistance meets the first standard and detects electricity to PSE feedback first by the inverting input terminal
Stream；
When the first detection electric current is unsatisfactory for given threshold, the control module controls in subsequent detection cycle
The first switch disconnects, and the resistance value of the detection resistance meets the second standard and by the inverting input terminal to the PSE
Feedback the second detection electric current；
When the second detection electric current meets the given threshold, the normal phase input end receives the PSE transmission
Operating voltage signal, the PD module are connected with the load blocks to start the work of the load blocks.
The embodiment of the present invention increases control module in receiving end equipment by the circuit structure of improvement receiving end equipment,
Control module main function is the power grade of active accommodation itself in order to when receiving end equipment can not successfully be identified by PSE
To adapt to the PSE of even lower level grade, specifically, connect with the first switch, in the inverting input terminal to the PSE
The detection electric current of feedback is unsatisfactory for opening the first switch when given threshold, to modulate the resistance value of the detection resistance, because
The detection resistance of PD is adjusted, so PSE can successfully identify PD in next period, therefore is started and is powered to PD.
Detailed description of the invention
To describe the technical solutions in the embodiments of the present invention more clearly, make required in being described below to embodiment
Attached drawing is briefly introduced, it should be apparent that, drawings in the following description are only some embodiments of the invention, for this
For the those of ordinary skill in field, without creative efforts, it can also be obtained according to these attached drawings other
Attached drawing.
Fig. 1 is a kind of POE application system for standard that the prior art provides；
Fig. 2 provides a kind of receiving end device structure schematic diagram for the embodiment of the present invention；
Fig. 3 provides a kind of receiving end circuitry figure one for the embodiment of the present invention；
Fig. 4 provides a kind of receiving end circuitry figure two for the embodiment of the present invention；
Fig. 5 provides a kind of receiving end circuitry figure three for the embodiment of the present invention；
Fig. 6 provides a kind of receiving end circuitry figure four for the embodiment of the present invention；
Fig. 7 provides a kind of receiving end plant capacity level adjustment method for the embodiment of the present invention；
Fig. 8 is a kind of receiving end equipment working timing figure provided in an embodiment of the present invention.
Specific embodiment
To make the objectives, technical solutions, and advantages of the present invention clearer, below in conjunction with attached drawing to the present invention make into
It is described in detail to one step, it is clear that the described embodiments are only some of the embodiments of the present invention, rather than whole implementation
Example.Based on the embodiments of the present invention, obtained by those of ordinary skill in the art without making creative efforts
All other embodiment, shall fall within the protection scope of the present invention.
For POE system, the control of power supply is divided into three phases, respectively include: detection, classification and power supply.Figure
1 show the POE application system of existing standard, comprising: PSE and PD.
Wherein, PSE is the power supply unit in POE system, for giving PD to provide electric energy, and detects whether PD legal and PD
Power grade equipment, PSE mainly uses PSE controller to realize three detection, classification, power supply working stages.It is detecting
When the stage, voltage signal of the PSE controller in out (output) pin output 43V or more, it should be noted that PSE output voltage
Volt value according to the models of different PSE controllers, the voltage value of output can be different, as the Q1 when gate pin exports low level
It closes, to guarantee the difference that the voltage of PD module input is 53V and 43V in figure, to provide the detection for detecting PD module
Voltage；At the stage of classification, gate pin keeps low level, and PSE controller exports a 32.5~37.5V's in out pin
Graded signal guarantees PD module input voltage in 15.5~20.5V, to make the work of PD module in the classification stage；In power supply rank
Duan Shi, gate pin export high level, and (high level voltage of different PSE controller output is different, as long as being greater than the 0.7V of Q1
Cut-in voltage both can, present invention assumes that being 10V), Q1 is opened, therefore out pin disconnects inside PSE controller, is equivalent to PSE control
The out of device processed is not connected to, and samples its both end voltage by sense pin since R1 is PSE controller to detect load
The small resistance of precision (different values being chosen according to the requirement of controller, it is assumed herein that being 0.2 ohm) of electric current, R1 is upper will not be because of
Obvious pressure drop is generated by load current, so this stage is equivalent to PSE and exports two output voltages of 53V and 0V to PD
The power supply to PD is realized at both ends.
Further, PD is network receiving end equipment for receiving the provided electric energy of PSE in Fig. 1, internal main packet
Containing two functional modules, one is PD module, and one is load blocks.PD is as follows in the working condition of detection-phase: being applied
When adding 10V detection voltage below, it is exactly to rely on that the resistance value of equivalent detection resistance, which is 23.75k Ω~26.25k Ω, PSE,
It identifies the electric current of detection resistance consumption, distinguishes whether connected device is PD.PD is as follows in the working condition in classification stage:
When being applied the tapping voltage of 15.5~20.5V, PD module is by applying a fixed voltage to CLS (classification) pin inside PD
(present invention assumes that being 2.5V), thus the electric current that the graded resistance consumption for connecting CLS pin is fixed, and PSE is exactly to pass through
The electric current on CLS pin is identified to judge that the power grade of PD, the electric current in Fig. 1 on CLS pin refer to branch where resistance R2
The electric current on road.PD is as follows in the working condition of powering phase: when being applied more than 36V or more supply voltage, (present invention is implemented
Official holiday is set as 53V), the VSS pin and RTN pin of PD module are equivalent to a straight-through conducting wire, and transparent transmission supplies voltage to load
Module.Load blocks can be different PD, and load blocks internal consumption electrical energy system runs circuit.
Currently, POE system has multiple supply standards, wherein 802.3af is a kind of supply standard of POE system, this mark
Brigadier PD points are 4 kinds of grade class0 to class3, and standard regulation, the maximum attachable PD of PSE is 15.4w.In addition,
802.3at is another supply standard of POE system, increases 4 calibration power of class, standard rule compared to 802.3af
Calmly, maximum power is 25.5w when the PD of class 4.
Because the grade that PD may have 0~class of class 4 so more, 0~class of class, 4 different brackets are corresponding
Different resistance, each graded resistance consume different electric currents, wherein defining class3 according to standard is 25~31mA, corresponding point
Grade resistance range is 80.6~100 Ω, and class4 is 35~45mA, corresponding 71.4~55.5 Ω of graded resistance range, class5
For 54~64mA, corresponding 46.3~39 Ω of graded resistance range.
Shown in Figure 2, the embodiment of the present invention provides a kind of receiving end device structure schematic diagram, specifically realizes structure packet
It includes: input terminal, PD module, load blocks, control module, detection resistance, in which:
The input terminal includes normal phase input end and inverting input terminal, and the normal phase input end is set for receiving feeder ear
The voltage of standby PSE transmission, the inverting input terminal are used to feed back detection electric current to the PSE in the stage；
The PD module, for starting the work of the control module and passing through institute when the PSE transmits detection voltage
It states inverting input terminal and feeds back detection electric current to the PSE；When the PSE transmits operating voltage, closure and the load blocks
Connection to start the load blocks；
The detection resistance, between the PD module and the inverting input terminal, for detection-phase work with
Detection electric current is fed back to the PSE, the detection resistance includes first resistor and second resistance in parallel；
The control module, including the first switch being connect with the second resistance, for the inverting input terminal to
The detection electric current of the PSE feedback is unsatisfactory for opening the first switch when given threshold, to modulate the resistance of the detection resistance
Value.
In Fig. 2, the first end (power supply VCC pin) of the PD module is connect with the normal phase input end, the PD mould
The second end (ground connection VSS pin) of block connect with the inverting input terminal, the third end (dividing CLS pin) of the PD module and
One end of detection resistance connects, and the 4th end (reflux RTN pin) of the PD module is connect, institute with one end of the load blocks
The other end for stating load blocks is connect with the normal phase input end；The other end of the detection resistance and the inverting input terminal connect
It connects；
After the PD module receives the tapping voltage signal of the PSE device transmission, it can be mentioned for the detection resistance
For operating voltage；If the detection electric current that the inverting input terminal is fed back to the PSE is unsatisfactory for given threshold, the control mould
Block adjusts the resistance value of the detection resistance, in Fig. 2 detection resistance initial value because the connection method of control module it is different, it is different
Value.When the connection type of control module as shown in figure 3, when being connected to the CLS pin of PD module, the detection resistance is full
Resistance value after initial resistance value when foot first standard is the resistance R1, resistance R2, resistance R3 are in parallel；Work as control module
Connection type as shown in figure 4, i.e. when being connected to the CLS pin of PD module, when the detection resistance meets first standard
Initial resistance value be resistance value after the resistance R1, resistance R2 in parallel.
Further, the control module includes concatenated between the normal phase input end and the inverting input terminal
3rd resistor, diode and capacitor；The first switch is the first metal-oxide-semiconductor, grid and the capacitor of first metal-oxide-semiconductor
Anode connection；
The capacitor after reaching predetermined value for the charging voltage in capacitor, controls first metal-oxide-semiconductor and opens, cause
The first resistor disconnects, so as to adjust the resistance value of the detection resistance.
In figs. 3 and 4, the series system of 3rd resistor, diode and capacitor can be sequentially connected as shown in the figure,
It can be sequentially connected with according to diode, 3rd resistor, capacitor.Wherein, the anode of diode is connect with 3rd resistor, and two
The effect of the cathode and capacitance connection of pole pipe, diode mainly prevents diode discharge in capacitor during the charging process.Control
Module is by the switch state to the first metal-oxide-semiconductor Q1 of capacitor charging and then control, so that resistance R1 accesses circuit when Q1 is connected,
Connection is disconnected from the circuit in Q1 shutdown.Because control module controls the connection status of resistance R1, the detection electricity of PD
Resistance is adjusted, so the power grade of PD also changes.
As shown in Figure 3, it is assumed that PD equipment sets initial fractional as class4, point that the CLS pin in PD module issues
Step voltage is 2.5V.According to POE standard define, PD when being class3 grade corresponding detection electric current be 25mA~31mA, correspondence
The CLS institute connecting detection resistance range of 2.5V CLS pin voltage is the Ω of 80.6 Ω~100；PD is corresponding when being class4 grade
Detection electric current is 35mA~45mA, and answering the CLS institute connecting detection resistance range of 2.5V CLS pin voltage is 55.5 Ω~71.4
Ω.Also, since resistance R1, resistance R2, resistance R3 are parallel connections, in order to guarantee just when CLS issues 2.5V voltage in figure
Often support the PSE device of class4 that can recognize the graded resistance of class4, so the all-in resistance of CLS must satisfy range
The Ω of 55.5 Ω~71.4, it may be assumed that
55.5 < R1*R2*R3/ (R1*R2+R2*R3+R1*R3) < 71.4............... (formula 1),
Therefore when supporting the PSE device of class3 grade to identify PD, resistance R1 just needs to disconnect, so CLS is managed
Foot only has resistance R2 and resistance R3 in parallel, according to the CLS resistance range Ω of 80.6 Ω~100 requirement of class3, it may be assumed that
80.6 < R2*R3/ (R2+R3) < 100............... (formula 2)
To meet formula 1 and formula 2 to choose suitable resistance and capacitor, the embodiment of the present invention provides such as under type
Determine the value range of resistance, i.e., according to formula 2, the value of resistance R2 has to satisfaction 80.6 < R2 < 100, and resistance R3 just has can
Energy value meets formula 2, so the embodiment of the present invention assumes 90 Ω of resistance R2 value, according to formula 2, then the value of resistance R3 is big
In 771, it is assumed that R3 value is 1000, acquires 169.2 < R3 < 526.6 further according to formula 1, it is herein assumed that R1 value 300.Here
R1, R2, R3, in actual design, as long as value meets formula 1 and formula 2, the value of resistance herein is only with typical case
Subsequent calculating process for convenience of explanation for value.
In the value for setting R1, R2, R3 and then determine capacitor C1 value, the embodiment of the present invention assumes the metal-oxide-semiconductor selected
It is 0.8V that Vgs voltage, which is connected, in Q1, and the conduction voltage drop of D1 is 0.3V, and the embodiment of the present invention fails according to 2 classifications, then reduces PD and set
Standby classification level is designed to class3.Then resistance R1 and capacitor C1 constitutes rc charging circuit, wherein capacitor C1 is in t
The d point voltage at quarter meets:
Vt=V0* (1-E^ (- t/ (R1*C1))) ... ... ... (formula 3)
Wherein, V0 is initial charge voltage, and E is math constant, and R1 is 1000 Ω.
Since the voltage of CLS pin is 2.5V, the pressure drop 0.3V of diode D1, since the grading time of PSE device is 14
~22ms (i.e. the duration of CLS output 2.5V), be connected to guarantee to be classified metal-oxide-semiconductor Q1 for the first time (i.e. Vgs=2.5-Vt >
0.8, Vt<1.7), second classification Q1 just turns off (i.e. Vgs=2.5-Vt≤0.8, Vt>=1.7), in conjunction with formula 3, first time
When classification when 14~22ms of t value, meet Q1 turn-on condition Vt < 1.7, the value of capacitor C1 is greater than 0.000015 at this time.When
28~44ms of t value when secondary grading, meet Q1 turn-on condition Vt >=1.7, so the value of capacitor C1 is less than or equal to
0.000019.In general 0.000015 < C1≤0.000019 can meet classification Q1 conducting for the first time, second of classification
Q1 is just turned off, and the embodiment of the present invention assumes that C1 value is 0.000017, i.e. 17uf.
When PD module receives the detection voltage of the PSE transmission, the third end of the PD module and the PD module
4th end is to disconnect, and control module charges to capacitor in the detection voltage period of first time detection cycle, charging capacitor
Voltage reach predetermined value Q1 disconnected, R1 is disconnected, and then the detection resistance of the composition of R2 and R3 to detect electric current
Meet corresponding detection electric current 25mA~31mA when PD is class3 grade, thus PSE assert PD for it is legal power set
It is standby, and then PD is powered.When PD module receives the operating voltage 53V of the PSE transmission, the third end of the PD module
It is closed with the 4th end of the PD module, thus to the power load modules of PD.
Further, it is contemplated that the detection resistance of PD, which changes, will affect PD and powered next time by PSE, therefore should restore
The detection resistance of PD is initial value, therefore the PD in the embodiment of the present invention further includes discharge module, as shown in figure 5, the electric discharge
Module includes: the second metal-oxide-semiconductor, third metal-oxide-semiconductor；
The source electrode of second metal-oxide-semiconductor is connect with the normal phase input end, the drain electrode of second metal-oxide-semiconductor and the 3rd MOS
The grid of pipe connects, and the grid of second metal-oxide-semiconductor is connect with the 4th end of the PD module, and second metal-oxide-semiconductor is described
The load blocks of PD are switched on after being powered；
The source electrode of the third metal-oxide-semiconductor is connect with the inverting input terminal, the drain electrode of the third metal-oxide-semiconductor and the capacitor
Anode connection, the third metal-oxide-semiconductor second metal-oxide-semiconductor conducting after be switched on so that the plus earth of the capacitor is put
Electricity.
Because in Fig. 5, after PD module receives operating voltage, RTN with VSS short circuit can be made to connect, make a point of load blocks
With e point signal, voltage difference i.e. Ve=0V, the Va=53V of 53V is formed, so that load blocks be allowed to be worked by electricity.But it is supplied in PSE
Before electricity, RTN and VSS are to disconnect, and e point only connects Q3, and according to the characteristic of PMOS, the e point input impedance of Q3 is infinity, this
When to be equivalent to e point be hanging, so the pressure difference of a and e is 0V, Va=Ve, i.e. Vgs=Ve-Va=0, Q3 are held off, at this time by
In the presence of R5, the g grade of Q2, i.e. f point is to pull down to ground, so the Vgs=0v of Q2, Q2 are also off, the voltage of C1 will not lead to
Cross Q2 release.After power supply, Vgs=Ve-Va=53V > 0.8V of Q3, Q3 conducting, f point Vf=53V, so the Vgs=of Q2
Vf-0=53V, so Q2 is connected, d point is shorted to ground by Q2, and the voltage of C1 is discharged into 0V by Q2.So the effect of Q2 is exactly
After a power up, C1 voltage is discharged rapidly, when guaranteeing that next time disconnects reconnection PSE device, detection resistance is initial value.
Likewise, the mode of release C1 voltage, can also be realized with R4, as shown in fig. 6, the discharge module includes the
Four resistance；4th resistance is connected between the anode and cathode of the capacitor, described for discharging the voltage of the capacitor
The ohmic value of 4th resistance is far longer than the ohmic value of the first resistor.
Because CLS is not no voltage after a power up, the voltage of C1 can all be discharged by R4 at this time, discharge time symbol
Close capacitor electric discharge formula:
Vt=Vd*E^ (- t/ (R4*C1)) ... ... ... ... .. (formula 4)
Wherein, Vd is current C1 capacitance voltage, and E is math constant, and Vt is that the C1 after discharging the t time by R4 is powered on
Pressure.The value that R4 can be thus set according to formula 4, guarantees after terminating last time and being classified, the set time releases
The voltage of C1, so that reconnect PSE next time be enable to execute operation above since initial fractional.Citing calculates as follows: such as
Upper setting, C1=0.000017, Vd such as timing diagram 8, are before discharge 2.1V, if we think setting, last time is classified into
2 seconds release C1 voltage, then according to formula 4, calculates to obtain R4=38k to 0.1V after function.
It should be noted that two kinds of discharge modes can achieve the purpose that electric discharge, in order to be able to achieve in fig. 8 last
After a detection cycle is classified successfully, C1 voltage is discharged, guarantees that since connection next time can identify just determining classification level again.
In addition, further, the grid of the third metal-oxide-semiconductor in Fig. 5 is by the 5th resistance eutral grounding, so that the third
The grid of metal-oxide-semiconductor voltage when hanging is zero.
The calculating in addition, connection type of the control module for Fig. 4, in the calculating process and Fig. 3 of this connection type
Process is similar, and the 2.5V voltage of CLS has only been changed into the 9V detection of a point and 18V is classified two voltage cycles and charges to C1, and
And initial fractional resistance becomes R1, R2 parallel connection by R1, R2, R3 parallel connection, the graded resistance after switching similarly becomes
R2.Its Computing Principle and the same above process of process, no longer do other calculation specifications herein.
Shown in Figure 7, the power grade method of adjustment process that the embodiment of the present invention provides a kind of receiving end equipment PD is shown
It is intended to, specifically implementation method includes:
Inspection of the normal phase input end of step S101, the PD in the first detection cycle for receiving power supply end equipment PSE transmission
When surveying voltage, the PD module of the PD is that the detection resistance of the PD provides operating voltage, and the control module of the PD controls the
One switch conduction, the resistance value of the detection resistance meet the first standard and feed back the to the PSE by the inverting input terminal
One detection electric current.
Step S102, when the first detection electric current is unsatisfactory for given threshold, the control module is in subsequent detection
The control first switch disconnects in period, and the resistance value of the detection resistance meets the second standard and passes through the inverting input terminal
To PSE feedback the second detection electric current.
Step S103, when the second detection electric current meets the given threshold, described in the normal phase input end reception
The operating voltage signal of PSE transmission, the PD module are connected with the load blocks to start the work of the load blocks.
Wherein, the detection resistance includes first resistor in parallel, second resistance, 3rd resistor, and the first switch is
First metal-oxide-semiconductor；The control module includes concatenated 3rd resistor, diode and capacitor, the grid of first metal-oxide-semiconductor and institute
State the anode connection of capacitor.
For the connection type of the control module of Fig. 3, the input terminal of the control module inputs the classification of the PD module
When voltage, start to the capacitor charging；The resistance value when detection resistance meets first standard be the first resistor,
Resistance value after the second resistance and the 3rd resistor are in parallel；The detection resistance meets resistance value when second standard
For the resistance value of the second resistance, the 3rd resistor after in parallel.
For the connection type of the control module of Fig. 4, the detection of the input terminal input normal phase input end of the control module
When voltage, start to the capacitor charging；Initial resistance value when the detection resistance meets first standard is described first
Resistance value after resistance, the second resistance are in parallel；The resistance value when detection resistance meets second standard is described the
The resistance value of two resistance.
As shown in figure 8, PSE device can send detection and classification when the PSE device of class3 is only supported in the connection of PD equipment
Signal, such as the normal phase input end received signal in Fig. 2.When graded signal is sent to normal phase input end, PD module can be in CLS
2.5V signal is exported on pin, as c point signal in Fig. 3 can be by CLS pin for the classification process of the first detection cycle
2.5V carries out first time charging to capacitor C1 by resistance R1, diode D1, and according to formula 3, the grading time of PSE is according to 18ms
Representative value sets (i.e. the charging time continues 18ms), and the d point of capacitor C1 can be charged to 1.4V, at this time the Vgs=of the first metal-oxide-semiconductor Q1
2.5-1.4=1.1V, greater than the cut-in voltage 0.8V of the first metal-oxide-semiconductor Q1, so the first metal-oxide-semiconductor Q1 is classified stage meeting in first time
It stays open, the total impedance on CLS pin is in parallel by resistance R1, resistance R2, resistance R3, and charges since capacitor C1 is in
Journey, equivalent parallel impedance can become larger, with the charging of capacitor C1 so resistance R1 is equivalent to punching in charging process
1000 ohm are stepped up big infinitely great (i.e. R3=1000, R2=90, R1 >=1000), so the total impedance of CLS pin at this time
Meet: 65=< R1*R2*R3/ (R1*R2+R2*R3+R1*R3) < 69 and meets 55.5~71.4 Ω requirement of class4.If
PSE can not identify class4, then this time classification failure, will continue to carry out detection classification next time.
And when the classification process of the second detection cycle, since first time classification has made d reach certain voltage, when second
When the classification of detection cycle, d point voltage continues to rise, and rises to 1.9V also according to 3, d point, at this time the Vgs=2.5-1.9 of Q1
=0.6V, the cut-in voltage 0.8V less than Q1, so Q1 can be turned off after being classified at second, CLS only has R3 and R2 simultaneously at this time
Connection, same CLS total impedance meet: 82.6=< R3*R2/ (R3+R2) < 90, meet the Ω of 80.6 Ω~100 requirement of class3.
Since second of classification is that occur impedance switching in classification process, although the resistor satisfied class3 requirement of CLS after switching,
PSE is to require the entire classification stage that will meet the requirements, so this stage can also be classified failure, continues third time detection point
Grade.
When the classification of third detection cycle, since CLS total impedance has met class3 requirement, PSE device can be classified
Success.And be powered, such as " power supply " stage of a point signal in Fig. 8.
Further, the discharge module of the PD discharges the voltage of the capacitor, restores the resistance of the detection resistance of the PD
Value meets first standard.
Discharge module can be discharged by the connection type in Fig. 5, i.e., the described normal phase input end receives the PSE transmission
After operating voltage signal, further includes: the second end of the PD module is connected with the 4th end, causes the 2nd MOS of discharge module
Pipe and the conducting of third metal-oxide-semiconductor, the plus earth electric discharge of the capacitor.
Specifically, after PSE provides the supply voltage of 53V, PD module can be such that RTN with VSS short circuit connects, and make load blocks
A and e point signal, voltage difference i.e. Ve=0V, the Va=53V of 53V is formed, so that load blocks be allowed to be worked by electricity.But in PSE
Before power supply, RTN and VSS are to disconnect, and e point only connects Q3, and according to the characteristic of PMOS, the e point input impedance of Q3 is infinity,
It is hanging for being equivalent to e point at this time, so the pressure difference of a and e is 0V, Va=Ve, i.e. Vgs=Ve-Va=0, Q3 are held off, at this time
Due to the presence of R5, the g grade of Q2, i.e. f point is to pull down to ground, so the Vgs=0v of Q2, Q2 are also off, the voltage of C1 will not
It is discharged by Q2.After power supply, Vgs=Ve-Va=53V > 0.8V of Q3, Q3 conducting, f point Vf=53V, so the Vgs of Q2
=Vf-0=53V, so Q2 is connected, d point is shorted to ground by Q2, and the voltage of C1 is discharged into 0V by Q2, such as the d point signal of Fig. 3
Final stage.So the effect of Q2 is exactly after a power up, to discharge rapidly C1 voltage, when guaranteeing that next time disconnects reconnection PSE device,
The process of Fig. 8 can be reruned.
Similarly, the mode of discharge module release C1 voltage can also be realized with R4 in Fig. 6, because after a power up
CLS is not no voltage, and the voltage of C1 can all be discharged by R4 at this time, and discharge time meets capacitor electric discharge formula 4.Thus
The value that R4 can be set according to formula 4 guarantees that after terminating last time and being classified, the set time releases the voltage of C1,
To enable reconnect PSE next time to execute operation above since initial fractional.Citing calculates as follows: as above setting, C1
=0.000017, Vd such as Fig. 8 are before discharge 2.1V, if we want to set 2 seconds release C1 after last time is classified successfully
Voltage is to 0.1V, then according to formula 4, calculates to obtain R4=38k.Two kinds of discharge modes are ok, as long as being able to achieve in last time
After being classified successfully, C1 voltage is discharged, guarantees that since connection next time can identify just determining classification level again.
In conclusion the embodiment of the present invention is increased in receiving end equipment by the circuit structure of improvement receiving end equipment
Control module, control module main function be in order to when receiving end equipment can not successfully be identified by PSE, active accommodation itself
Power grade is specifically connect with the first switch with the PSE for adapting to even lower level grade, in the inverting input terminal
The detection electric current fed back to the PSE opens the first switch when being unsatisfactory for given threshold, to modulate the detection resistance
Resistance value, because the detection resistance of PD is adjusted, PSE can successfully identify PD in next period, therefore start and power to PD.
The present invention be referring to according to the method for the embodiment of the present invention, the process of equipment (system) and computer program product
Figure and/or block diagram describe.It should be understood that every one stream in flowchart and/or the block diagram can be realized by computer program instructions
The combination of process and/or box in journey and/or box and flowchart and/or the block diagram.It can provide these computer programs
Instruct the processor of general purpose computer, special purpose computer, Embedded Processor or other programmable data processing devices to produce
A raw machine, so that being generated by the instruction that computer or the processor of other programmable data processing devices execute for real
The device for the function of being specified in present one or more flows of the flowchart and/or one or more blocks of the block diagram.
These computer program instructions, which may also be stored in, is able to guide computer or other programmable data processing devices with spy
Determine in the computer-readable memory that mode works, so that it includes referring to that instruction stored in the computer readable memory, which generates,
Enable the manufacture of device, the command device realize in one box of one or more flows of the flowchart and/or block diagram or
The function of being specified in multiple boxes.
These computer program instructions also can be loaded onto a computer or other programmable data processing device, so that counting
Series of operation steps are executed on calculation machine or other programmable devices to generate computer implemented processing, thus in computer or
The instruction executed on other programmable devices is provided for realizing in one or more flows of the flowchart and/or block diagram one
The step of function of being specified in a box or multiple boxes.
Although preferred embodiments of the present invention have been described, it is created once a person skilled in the art knows basic
Property concept, then additional changes and modifications may be made to these embodiments.So it includes excellent that the following claims are intended to be interpreted as
It selects embodiment and falls into all change and modification of the scope of the invention.
Obviously, various changes and modifications can be made to the invention without departing from essence of the invention by those skilled in the art
Mind and range.In this way, if these modifications and changes of the present invention belongs to the range of the claims in the present invention and its equivalent technologies
Within, then the present invention is also intended to include these modifications and variations.
Claims (12)
1. a kind of receiving end equipment PD, which is characterized in that the PD includes: input terminal, PD module, load blocks, control module
And detection resistance；
The input terminal includes normal phase input end and inverting input terminal, and the normal phase input end is for receiving power supply end equipment
The voltage of PSE transmission, the inverting input terminal are used to feed back detection electric current to the PSE；
The PD module, for starting the work of the control module and by described anti-when the PSE transmits detection voltage
Phase input terminal feeds back detection electric current to the PSE；When the PSE transmits operating voltage, the company of closure and the load blocks
It connects to start the load blocks；
The detection resistance, between the PD module and the inverting input terminal, for working in detection-phase with to institute
PSE feedback detection electric current is stated, the detection resistance includes first resistor and second resistance in parallel；
The control module, including the first switch being connect with the second resistance, in the inverting input terminal to described
The detection electric current of PSE feedback is unsatisfactory for opening the first switch when given threshold, to adjust the resistance value of the detection resistance.
2. equipment as described in claim 1, which is characterized in that the control module includes being located at the normal phase input end and institute
State concatenated 3rd resistor, diode and capacitor between inverting input terminal；
The first switch is the first metal-oxide-semiconductor, and the grid of first metal-oxide-semiconductor is connect with the anode of the capacitor；
The capacitor after reaching predetermined value for the charging voltage in capacitor, controls first metal-oxide-semiconductor and opens, causes described
First resistor disconnects, so as to adjust the resistance value of the detection resistance.
3. equipment as claimed in claim 2, which is characterized in that the power supply VCC pin and the positive of the PD module input
End connection, the ground connection VSS pin of the PD module are connect with the inverting input terminal；
One end of the detection resistance is connect with the partial pressure CLS pin of the PD module, the other end of the detection resistance and institute
Inverting input terminal connection is stated, the PD module is when receiving the detection voltage of the PSE transmission, the ground connection VSS of the PD module
Pin and the partial pressure CLS pin of the PD module are closed, the reflux of partial pressure the CLS pin and the PD module of the PD module
RTN pin disconnects；
One end of the load blocks is connect with the reflux RTN pin of the PD module, the other end of the load blocks and institute
Normal phase input end connection is stated, the PD module is when receiving the operating voltage of the PSE transmission, the ground connection VSS of the PD module
Pin and the partial pressure CLS pin of the PD module disconnect, the reflux of partial pressure the CLS pin and the PD module of the PD module
RTN pin closure.
4. equipment as claimed in claim 1 or 2, which is characterized in that further include: discharge module；
The discharge module includes the 4th resistance；
4th resistance is connected between the anode and cathode of capacitor, for discharging the voltage of the capacitor, the 4th electricity
The ohmic value of resistance is greater than the ohmic value of the first resistor.
5. equipment as claimed in claim 3, which is characterized in that further include discharge module；
The discharge module includes: the second metal-oxide-semiconductor, third metal-oxide-semiconductor；
The source electrode of second metal-oxide-semiconductor is connect with the normal phase input end, drain electrode and the third metal-oxide-semiconductor of second metal-oxide-semiconductor
Grid connection, the grid of second metal-oxide-semiconductor are connect with the reflux RTN pin of the PD module, and second metal-oxide-semiconductor is described
The load blocks of PD are switched on after being powered；
The source electrode of the third metal-oxide-semiconductor is connect with the inverting input terminal, the drain electrode of the third metal-oxide-semiconductor and the sun of the capacitor
Pole connection, the third metal-oxide-semiconductor is switched on after second metal-oxide-semiconductor conducting, so that the plus earth of the capacitor is discharged.
6. equipment as claimed in claim 5, which is characterized in that further include:
The grid of the third metal-oxide-semiconductor is by the 5th resistance eutral grounding, so that the grid of third metal-oxide-semiconductor voltage when hanging is
Zero.
7. a kind of power grade method of adjustment of receiving end equipment PD, which is characterized in that this method comprises:
The normal phase input end of the PD is described when receiving the detection voltage of the first detection cycle of power supply end equipment PSE transmission
The PD module of PD provides operating voltage, the control module control first switch conducting of the PD, institute for the detection resistance of the PD
The resistance value for stating detection resistance meets the first standard and detects electric current to PSE feedback first by inverting input terminal；
When the first detection electric current is unsatisfactory for given threshold, described in the control module controls in subsequent detection cycle
First switch disconnects, and the resistance value of the detection resistance meets the second standard and fed back by the inverting input terminal to the PSE
Second detection electric current；
When the second detection electric current meets the given threshold, the normal phase input end receives the work of the PSE transmission
Voltage signal, the PD module are connected with load blocks to start the work of the load blocks.
8. the method for claim 7, which is characterized in that the control module control first switch conducting of the PD, comprising:
For the normal phase input end when receiving the detection voltage of the first detection cycle of the PSE transmission, capacitor is in charging shape
The state and charging voltage of the capacitor makes the first switch in the conductive state, causes the resistance value of the detection resistance to meet
First standard；
The control module controls the first switch in subsequent detection cycle and disconnects, comprising:
The normal phase input end receives the detection voltage of the second detection cycle of the PSE transmission, and the capacitor is in charging shape
The state and charging voltage of the capacitor is in an off state the first switch tube causes the resistance value of the detection resistance full
Foot second standard；
Meet the given threshold in the second detection electric current, comprising:
The inverting input terminal meets the setting threshold in the second detection electric current that third detection cycle is fed back to the PSE
Value.
9. method according to claim 8, which is characterized in that the detection voltage includes initial survey voltage and tapping voltage；Institute
Stating detection resistance includes first resistor and second resistance in parallel；The first switch is the first metal-oxide-semiconductor；The control module packet
Concatenated 3rd resistor, diode and capacitor are included, the grid of first metal-oxide-semiconductor is connect with the anode of the capacitor；
When the input terminal of the control module inputs the tapping voltage of the PD module, start to the capacitor charging；
The resistance value when detection resistance meets first standard is the first resistor, the second resistance and the third
Resistance value after resistor coupled in parallel；
The resistance value when detection resistance meets second standard is after the second resistance, the 3rd resistor are in parallel
Resistance value.
10. method according to claim 8, which is characterized in that the detection voltage includes initial survey voltage and tapping voltage；Institute
Stating detection resistance includes first resistor and second resistance in parallel；The first switch is the first metal-oxide-semiconductor；The control module packet
Concatenated 3rd resistor, diode and capacitor are included, the grid of first metal-oxide-semiconductor is connect with the anode of the capacitor；
When the input terminal of the control module inputs the initial survey voltage, start to the capacitor charging；
The resistance value when detection resistance meets first standard is after the first resistor, the second resistance are in parallel
Resistance value；
The resistance value when detection resistance meets second standard is the resistance value of the second resistance.
11. such as the described in any item methods of claim 7 to 10, which is characterized in that the PD module is led with the load blocks
After passing to the work for starting the load blocks, further includes:
The voltage of the discharge module release capacitor of the PD, the resistance value for restoring the detection resistance of the PD meet first mark
It is quasi-.
12. method as claimed in claim 11, which is characterized in that the discharge module of the PD discharges the voltage of the capacitor,
Include:
After the normal phase input end receives the operating voltage signal of PSE transmission, the ground connection VSS pin of the PD module with
Flow back the conducting of RTN pin, causes the second metal-oxide-semiconductor of discharge module and the conducting of third metal-oxide-semiconductor that the capacity earth discharges.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610580475.1A CN106161041B (en) | 2016-07-20 | A kind of power grade method of adjustment of receiving end equipment and receiving end equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610580475.1A CN106161041B (en) | 2016-07-20 | A kind of power grade method of adjustment of receiving end equipment and receiving end equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106161041A CN106161041A (en) | 2016-11-23 |
| CN106161041B true CN106161041B (en) | 2019-07-16 |
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