CN206685915U

CN206685915U - A kind of circuit protection circuit and power cable

Info

Publication number: CN206685915U
Application number: CN201720017286.3U
Authority: CN
Inventors: 龚勇
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2017-01-06
Filing date: 2017-01-06
Publication date: 2017-11-28
Anticipated expiration: 2027-01-06

Abstract

The utility model discloses a kind of circuit protection circuit, including：The self- recoverage protection circuit that first monitoring for protection circuit, first switch circuit and direct impedance are varied with temperature and changed；The first monitoring for protection circuit, the first voltage for obtaining the self- recoverage protection circuit both ends is poor, when first voltage difference is beyond the first default protection voltage difference threshold value, to the cut-off signals of first switch circuit output first；The first switch circuit, for the electric current that when receiving first cut-off signals, power cutoff exports.The invention also discloses a kind of power cable.

Description

A kind of circuit protection circuit and power cable

Technical field

It the utility model is related to supply line's security protection technology, more particularly to a kind of circuit protection circuit and supply lines Cable.

Background technology

With the development of technology, mobile terminal has turned into user's routine use frequently equipment so that the power consumption speed of terminal Rate is more and more faster, so as to which the charging to end cell is also more and more frequent therewith；In order to there is the experience of more preferable user, shortening is filled Electric time, quick charge turn into the technology that mobile terminal must be supported；Currently, the essence of main flow quick charge is exactly that increase is filled The power output of electrical equipment, increase charging current in the charging curve scope of battery；In charging process, many cellphone subscribers meet Arrived charger lead-out terminal connector micro-short circuit occurs when mobile phone charges after, connector is burnt the safety problem melted；It is special It is not general Micro USB or TYPE the C connectors of current mobile terminal, due to physical dimension limitation and interface open type, uses In use, the oblique plug of plugs and sockets is damaged at family, plug exert oneself it is excessive fracture, or foreign matter enters, and is formed largely Conducting liquid and metal dust, cause charger cable that micro-short circuit occurs inside socket；It is short that micro-short circuit is unable to reach charger Road protective condition, therefore charger continuous output, in the Internal reforming formation heat of connector；Or as plug number increases Adding, the golden finger surface of plug and socket aoxidizes, and causes contact resistance to become big, causes to generate heat during charging, when Electric current increase, which seems, to be particularly acute, and ultimately results in data wire or Charger (portable round) or handset port melted by heat, smolder, be on fire etc. Security incident.

There is segmentation scheme by being assembled in data wire or charge cable on the power line of the charge circuit of plug position Thermistor, when connector inner heat to a certain extent when, thermistor is influenced by ambient temperature to change its resistance, so as to Change the resistance value on the power line by thermistor, decrease the electric current by connector.But when reducing electric current, together Sample, which can allow generate heat at connector heating, to be weakened, and temperature reduces, and thermistor recovers normal condition, moves in circles and be not easy again It is noticeable.Moreover, the effective access times of protection device of the restorability such as current thermistor are limited, there is potential safety hazard For several times after charging process, the safeguard measure of cable will be caused to fail.

Therefore, how to be cut off the electricity supply when potential safety hazard occurs, and be avoided that the feelings for moving in circles and cutting off the electricity supply Condition, Supply Security is improved, is urgent problem to be solved.

Utility model content

In view of this, the utility model embodiment it is expected to provide a kind of circuit protection circuit and power cable, is avoided that hair The raw situation about cutting off the electricity supply that moves in circles, improves Supply Security.

To reach above-mentioned purpose, what the technical solution of the utility model was realized in：

The utility model embodiment provides a kind of circuit protection circuit, and the circuit includes：

The self- recoverage protection circuit that direct impedance is varied with temperature and changed；

It is poor to obtain the first voltage at the self- recoverage protection circuit both ends, and it is default beyond first in first voltage difference To the first monitoring for protection circuit of the cut-off signals of first switch circuit output first during protection voltage difference threshold value；

When receiving first cut-off signals, the first switch circuit of power cutoff output current；

One end of the first switch circuit connects one end of the self- recoverage protection circuit, the first monitoring for protection electricity Both ends of two test sides on road respectively with the self- recoverage protection circuit are connected, and the control of the first monitoring for protection circuit is defeated Go out end to be connected with the first switch control terminal of the first switch circuit.

In such scheme, the circuit also includes：

It is poor to obtain the second voltage at the self- recoverage protection circuit both ends, and it is default beyond second in second voltage difference The second monitoring for protection circuit of the second cut-off signals is inputted when protecting voltage difference threshold value to second switch circuit；

When receiving second cut-off signals, the second switch circuit of the electric current of the power supply output is turned off；

One end of the second switch circuit connects one end of the self- recoverage protection circuit, the second monitoring for protection electricity Both ends of two test sides on road respectively with the self- recoverage protection circuit are connected, and the control of the second monitoring for protection circuit is defeated Go out end to be connected with the first switch control terminal of the second switch circuit.

In such scheme, the circuit also includes：

Power supply electrifying state is detected, is referred in the power supply electrifying to the Continuity signal of first switch circuit output first Show the first power on detection circuit of the output current of power supply described in first switch circuit turn-on；

The upper electro-detection end of first power on detection circuit is connected with power output end, first power on detection circuit Conducting control terminal be connected with the second switch control terminal of the first switch circuit.

In such scheme, the circuit also includes：

Power supply electrifying state is detected, is referred in the power supply electrifying to the Continuity signal of second switch circuit output second Show the second power on detection circuit of the output current of power supply described in second switch circuit turn-on；

The upper electro-detection end of second power on detection circuit is connected with power output end, second power on detection circuit Conducting control terminal be connected with the second switch control terminal of the second switch circuit.

In such scheme, the circuit protection circuit has two, and in the same direction or reverse parallel connection is set.

In such scheme, one in described two circuit protection circuits is replaced using the path of one-way conduction.

In such scheme, the self- recoverage protection circuit is arranged at by the heating position of protection circuit.

In such scheme, the first monitoring for protection circuit includes：It is arranged in parallel in the same direction with the self- recoverage protection circuit More than one PN junction semiconductor components and devices；

The conduction voltage drop of the PN junction semiconductor components and devices is the first default protection voltage difference threshold value.

In such scheme, the first switch circuit includes：First field-effect (MOS) pipe, the first triode, the first electricity Resistance, wherein, the grid of first metal-oxide-semiconductor is connected with the colelctor electrode of the first triode is used as the second control terminal, the first triode Base stage and one end of first resistor connect first switch control terminal as the first switch circuit, the hair of the first triode Emitter-base bandgap grading and the other end of first resistor are connected and are grounded.

In such scheme, first metal-oxide-semiconductor is P-channel field-effect transistor (PEFT) pipe, and the first metal-oxide-semiconductor grid is additionally provided with NOT gate； First triode is NPN triode.

In such scheme, first power on detection circuit includes：Second resistance, described second resistance one end and first Metal-oxide-semiconductor source electrode is connected, and the other end is connected with the first metal-oxide-semiconductor grid.

In such scheme, the second monitoring for protection circuit includes：It is arranged in parallel in the same direction with the self- recoverage protection circuit More than one PN junction semiconductor components and devices；

The conduction voltage drop of the PN junction semiconductor components and devices is defined as the second default protection voltage difference threshold value.

In such scheme, the second switch circuit includes：Second metal-oxide-semiconductor, the second triode, 3rd resistor, wherein, the Input of the two metal-oxide-semiconductor source electrodes as the second switch circuit, the second metal-oxide-semiconductor grid are connected with the colelctor electrode of the second triode As the second control terminal, one end of the base stage of the second triode and 3rd resistor connects first as the second switch circuit Switch control terminal, the emitter stage of the second triode and the other end of 3rd resistor are connected and are grounded, the drain electrode of second metal-oxide-semiconductor For the output end of the first switch circuit.

In such scheme, second metal-oxide-semiconductor is P-channel field-effect transistor (PEFT) pipe, and the second metal-oxide-semiconductor grid is additionally provided with NOT gate； Second triode is NPN triode.

In such scheme, second power on detection circuit includes：4th resistance, described 4th resistance one end and second Metal-oxide-semiconductor source electrode is connected, and the other end is connected with the second metal-oxide-semiconductor grid.

The utility model embodiment additionally provides a kind of power cable, is connected by connector with power supply or power receiving equipment； The power cable includes the circuit protection circuit any one of such scheme.

In such scheme, the circuit protection circuit is arranged at the link position of the power cable and the connector.

In such scheme, the circuit protection circuit is respectively arranged at the connection position at power cable both ends and the connector Put.

Circuit protection circuit, method and the power cable that the utility model embodiment is provided, set itself in the line The self- recoverage protection circuit that impedance is varied with temperature and changed；The first monitoring for protection circuit obtains the self- recoverage protection electricity The first voltage at road both ends is poor, when first voltage difference is beyond the first default protection voltage difference threshold value, is opened to described first Close the cut-off signals of circuit output first；For the first switch circuit when receiving first cut-off signals, power cutoff is defeated The electric current gone out.In this way, being cut off the electricity supply when potential safety hazard occurs, and the situation for moving in circles and cutting off the electricity supply is avoided that, carried High Supply Security.

Brief description of the drawings

Fig. 1 is the composition structural representation of the utility model embodiment circuit protection circuit；

Fig. 2 is the composition structural representation of the utility model embodiment bidirectional current circuit protection circuit；

Fig. 3 is the composition knot for the bidirectional current circuit protection circuit that the utility model embodiment shares self- recoverage protection circuit Structure schematic diagram；

Fig. 4 is the composition structural representation for the bidirectional current circuit protection circuit that the utility model embodiment simplifies；

Fig. 5 is the composition structural representation that the utility model embodiment circuit protection circuit and contact resistance detect association schemes Figure；

Fig. 6 is the utility model embodiment circuit protection circuit example conspectus；

Fig. 7 is the schematic flow sheet of the utility model embodiment line protection method；

Fig. 8 is circuit protection circuit set location schematic diagram in the utility model embodiment power cable；

Fig. 9 is that two terminal adapter circuit protection circuits set schematic diagram in the utility model embodiment power cable.

Embodiment

In the utility model embodiment, the self- recoverage protection for setting direct impedance to vary with temperature and change in the line is electric Road；The first voltage that the first monitoring for protection circuit obtains the self- recoverage protection circuit both ends is poor, when the first voltage When difference is beyond the first default protection voltage difference threshold value, to the cut-off signals of first switch circuit output first；Described first opens Powered-down road is when receiving first cut-off signals, the electric current of power cutoff output.

The utility model is further described in more detail with reference to embodiment.

The circuit protection circuit that the utility model embodiment provides, as shown in figure 1, the circuit protection circuit includes：The The self- recoverage protection circuit 11 that one monitoring for protection circuit 12, first switch circuit 13 and direct impedance are varied with temperature and changed；

Here, the power cable used during with charge power supply to terminal charge, such as USB cable, exemplified by illustrate that this practicality is new Type embodiment；The circuit protection circuit can be arranged in the power line of the power cable, be such as arranged on the 5V of USB cable In power line；The direct impedance of self- recoverage protection circuit 11 is varied with temperature and changed, and can be direct impedance with temperature liter It is high and raise or disconnected when temperature reaches preset temperature, high impedance status is presented, and recover normal temperature in temperature Shi Huifu low impedance states；

Self- recoverage protection circuit 11 can be arranged on power line both ends close to connector, as USB connector pin at, Just it is proximate at the power pins of terminal charge interface.When in temperature normal range of operation, the self- recoverage protection circuit 11 is in Existing extremely low impedance, so as to when electric current is by that and will not cause too big pressure drop；Because foreign matter enters or connector at connector The generation micro-short circuit phenomenon of the internal power path caused by plug causes physical damage and other electric paths, charge power supply are given Because micro-short circuit produces heating when terminal is powered；Or the socket and plug of connector causes golden finger surface golden because of long-term plug Category oxidation, produces larger contact impedance, so that connector produces heating because of contact impedance；The self- recoverage protection circuit 11, because of temperature rise in connector, cause impedance to raise；Such as connector temperature because power-off or failture evacuation return to safe temperature model Enclose, self- recoverage protection circuit returns to normal operating conditions impedance；The self- recoverage protection circuit 11 is positioned close to connector electricity At the golden finger of source pin, faster to sense change of the connector in electric current by rear temperature.

The self- recoverage protection circuit 11 can use positive temperature coefficient (PTC, Positive Temperature Coefficient) thermistor or breaker (Breaker) equitemperature protection device.As shown in figure 1, first flows to electric current warp After first switch circuit 13 and self- recoverage protection circuit 11, it is powered by the power pins of connector to terminal.Described The input of one on-off circuit 13 connection first flows to the affiliated power output end of electric current, described in the connection of the output end of first switch circuit 13 The input of self- recoverage protection circuit 11, two test sides of the first monitoring for protection circuit 12 are protected with the self- recoverage respectively The input of circuit 11 connects with output end, control output end and the first switch electricity of the first monitoring for protection circuit 12 The first switch control terminal connection on road 13, the power pins output electricity of the output end of the self- recoverage protection circuit 11 connection connector Stream；Power output end, two inspections of the first monitoring for protection circuit 12 can also be connected by the self- recoverage protection circuit 11 Survey end to be connected with the input and output end of the self- recoverage protection circuit respectively, the input of the first switch circuit 13 connects It is connected to the output end for recovering protection electricity 11, control output end and the first switch circuit of the first monitoring for protection circuit 12 13 first switch control terminal connection, the power pins output current of the output end of the first switch circuit 13 connection connector；

Generally, charge power supply connection external power supply, such as civil power etc., charge power supply output charging current.Now power line On power supply can undergo a power up, the phenomenon showed be charge power supply from zero to fixed voltage value rising Journey, such as the change from 0V to 5V.Charging current passes through first switch circuit 13, self- recoverage protection circuit 11 and connector Power pins, it is possible to allow power supply to be output to terminal.

In whole power supply process, PTC thermistor or Breaker equitemperature protectors in self- recoverage protection circuit 11 Part carries out performance change with the temperature change inside connector；Once because caused by micro-short circuit or contact resistance inside connector Temperature rises to some threshold value, PTC resistor or Breaker temperature protection device starting protection functions, the phenomenon showed it One is exactly that the current capacity passed through reduces and impedance increase.

The first monitoring for protection circuit 12, for obtaining the self- recoverage protection circuit both ends when first flows to electric current First voltage it is poor, when first voltage difference is beyond the first default protection voltage difference threshold value to the first switch circuit 13 Export the first cut-off signals；

First monitoring for protection circuit 12 is used to monitor whether self- recoverage protection circuit 11 has been started up protecting, i.e., self- recoverage is protected Whether the voltage difference at the both ends of protection circuit 11 is beyond the first default protection voltage difference threshold value, when the first monitoring for protection circuit 12 detects When self- recoverage protection circuit 11 has started to protection, illustrate to have generated heat at connector interior power pin；Now, the first monitoring for protection electricity Road 12 sends the first cut-off signals, the deenergization path of control first switch circuit 13 so that no current passes through connector.

First monitoring for protection circuit 12 can include the PN junction semiconductor components and devices of one or more one-way conductions, such as two poles Pipe, diode direction is consistent with the first direction of current, in parallel with self- recoverage protection circuit 11, when self- recoverage protection circuit 11 PTC thermistor or Breaker equitemperature protection device normal works when, conducting resistance is very small, caused pressure drop nor Often small, the diode in the first monitoring for protection circuit 12 is not turned on, and the pressure drop at diode both ends is the pressure drop of protection location；When certainly The PTC thermistor or the protection of Breaker equitemperatures protection device for recovering protection circuit 11 are opened, and impedance varies with temperature certain In individual threshold range, the pressure drop is more than or equal to the conduction voltage drop of diode so that diode current flow；Can according to demand, if PN junction semiconductor components and devices forward conduction voltage drop is put, i.e. the conduction voltage drop of diode is the first default protection electricity of temperature protection Threshold pressure differential.

Meanwhile first monitoring for protection circuit 12 first shut-off sent according to the described first default protection voltage difference threshold value believed Number, the first cut-off signals are output to first switch circuit 13 and close power path；After power path is closed, self- recoverage protection circuit 11 and the equal no current of connector by the way that the failure of micro-short circuit or contact resistance will not continue to cause heating.

The setting of described first default protection voltage difference threshold value can be according to the protection temperature setting of circuit；Such as it is expected to protect Temperature be 50 degrees Celsius, then can predefine at 50 degrees Celsius, the resistance of the self- recoverage protection circuit 11, according to electricity The product of the resistance of first in the road protection circuit of self- recoverage when flowing to electric current and 50 degrees Celsius 11 is as the described first default protection Voltage difference threshold value, when temperature is more than 50 degrees Celsius, the both end voltage difference of self- recoverage protection circuit 11 can be more than described first Default protection voltage difference threshold value, at this point it is possible to export the first cut-off signals to the first switch circuit 13.

In practical application, the first monitoring for protection circuit 12 can be triggered by the threshold voltage being made up of discrete component Circuit, the control circuits such as single-chip microcomputer can also be used to realize the function of the first monitoring for protection circuit 12

The first switch circuit 13, electric current is flowed to on or off first, receives first cut-off signals When turn off described first and flow to electric current；

The first switch circuit 13 is used to controlling the conducting and disconnection of charge power supply circuit, during normal operating conditions, the One on-off circuit 13 turns on；When the self- recoverage protection circuit 11 starts defencive function, first switch circuit 13 disconnects electricity Source path, so, it is possible to avoid " heating-protection-heating " mistake that moves in circles of self- recoverage protection circuit in power supply process Journey；The first switch circuit 13 can have one or more control pin, the power on detection circuit 14 or the of external circuit first One monitoring for protection circuit 12 etc. can control the on or off of the first switch circuit 13 by controlling pin.

In practical application, the first switch circuit 13 can be by field-effect transistor integrated circuit and triode decile The on-off circuit that vertical element is combined into, special switch integrated circuit etc. can also be used.

In this way, the first monitoring for protection circuit 12, which remains, sends the first cut-off signals, make the first switch circuit 13 All the time state is off, makes whole circuit reset until user disconnects charge power supply；Controlled by the first monitoring for protection circuit 12 First switch circuit 13 processed, it can more effectively turn on and disconnect charge power supply path, prevent from being not turned off the feelings of charge power supply Under condition, self- recoverage protection circuit 11 is cooled because the cut-out of first switch circuit 13 first flows to electric current, and recover conducting first Flowing to electric current makes self- recoverage protection circuit 11 heat up again, so as to cause the process that moves in circles of " heating-protection-heating "；Enter And electric current can be flowed to by cut-out first and notify to break down in user's charging circuit, user can normally supply after investigating failure Electricity.

Further, the circuit protection circuit includes also including：First power on detection circuit 14；Electric-examination on described first Slowdown monitoring circuit 14 is used to, when first flows to the affiliated power supply electrifying of electric current, to the conducting of the first switch circuit 13 output first believe Number；The first switch circuit 13, for flowing to electric current according to first Continuity signal conducting described first；On described first The upper electro-detection end of power detection circuit 14 flows to the affiliated power output end of electric current with first and is connected, first power on detection circuit 14 conducting control terminal is connected with the second switch control terminal of the first switch circuit 13.

In practical application, the power supply on power line can undergo a power up, and the phenomenon showed is charge power supply From zero to fixed voltage value uphill process, such as the change from 0V to 5V, first power on detection circuit 14 can utilize Rising edge during power supply electrifying produces the first Continuity signal, the tunnel of first switch circuit 13 is according to as trigger signal First Continuity signal conducting described first flows to electric current.

In some usage scenarios, such as USB type C power line, two terminal adapters of the power line are complete one Sample, position can exchange for charge power supply and terminal opposed power line, and therefore, the direction that electric current flows on the power line can Can meeting on the contrary, relative to original first flow to electric current have a flow direction conversely second flow to electric current；Such as USB type C power line has two identical connectors 1 and connector 2, when connector 1 is connected to charger, sense of current From connector 1 to connector 2, to be properly termed as first and flowing to electric current, when connector 2 is connected to charger, sense of current From connector 2 to interface 1, to be properly termed as second and flowing to electric current；At this moment, can be on the circuit that two inverse currents can flow through In the same direction or reverse parallel connection sets two groups of identical circuit protection circuits, is respectively used to protection first and flows to electric current and the second flow direction electricity Stream, the method that reverse parallel connection is set is as shown in Fig. 2 the direction of protection circuit setting is corresponding with electric current；Positive route protection Circuit is used for circuit during protective current forward flow, ends during reverse direction current flow；Reverse circuit protection circuit is used to protect Circuit during reverse direction current flow is protected, is ended during electric current forward flow.

Further, for the electric current of two kinds of flow directions on same power line, it can use and share self- recoverage protection circuit 11 Circuit protection circuit；As shown in figure 3, the circuit protection circuit also includes：Second monitoring for protection circuit 15, second switch electricity The power on detection circuit 17 of road 16 and second.It is defeated that the input of second switch circuit 16 connection second flows to the affiliated power supply of electric current Go out end, the output end of second switch circuit 16 connects the input of self- recoverage protection circuit 11, the second monitoring for protection circuit 15 two test sides are connected with the input and output end of the self- recoverage protection circuit 11 respectively, second monitoring for protection The control output end of circuit 15 is connected with the first switch control terminal of the second switch circuit 16；Using PTC thermistor It is either positive or the self- recoverage protection circuit 11 of Breaker equitemperature protection devices senses for the heating inside connector First flow to electric current or reverse second flow to electric current all can with connector internal temperature change and change, so first-class Same self- recoverage protection circuit 11 can be shared by flowing to electric current to electric current and second.

When electric current be first flow to electric current when, by self- recoverage protection circuit 11, first switch circuit 13, electro-detection on first The monitoring for protection circuit 12 of circuit 14 and first is protected to connector；When electric current flows to electric current for second, protected by self- recoverage Protection circuit 11, second switch circuit 16, the second power on detection circuit 17 and the second monitoring for protection circuit 15 are protected to connector Shield.The second monitoring for protection circuit 15 obtains the both ends of self- recoverage protection circuit 11 and flows to the second electricity under electric current second Pressure difference, when second voltage difference is beyond the second default protection voltage difference threshold value to the second switch circuit 16 input second Cut-off signals；Wherein, the first default protection voltage difference threshold value and the second default protection voltage difference threshold value can be with identical；Described second On-off circuit 16, described second is turned off when receiving second cut-off signals and flows to electric current；The second monitoring for protection circuit Second cut-off signals of 15 outputs make the second open-end circuit 16 be always maintained at turning off, and until user's shut-off charge power supply, make whole Circuit restoration, it could be turned on again after re-powering；Second power on detection circuit 17, the affiliated power supply of electric current is flowed to second When upper electric, the second Continuity signal is exported to the second switch circuit 16；The second switch circuit 16, led according to described second Messenger conducting described second flows to electric current；The upper electro-detection end of second power on detection circuit 17 and second flows to electric current institute Belong to power output end connection, the conducting control terminal of second power on detection circuit 17 and the second of the second switch circuit 16 Switch control terminal connects.

As shown in figure 4, in practical application, in circuit when second flows to, the output that can be generally connected by connector is electric Source carries out output current protection, therefore, can eliminate the self- recoverage defencive function of the second direction of current, use second Substituted to current path circuit.Second flow to current path circuit be in order to ensure the one-way of power path, meanwhile, Ke Yibao Demonstrate,prove the Consumer's Experience of cable.Such as when the cable is TYPE-C charge cable, input/output terminal minor structure is the same, connection Device role can redefine on demand.Second flows to the path that current path circuit can be an one-way conduction, such as Single-way switch circuit being made up of metal-oxide-semiconductor etc. etc..

In practical application, configured information can be provided and be used to identify the cable working condition in work.Such as sent out with green Optical diode (LED, Light-Emitting Diode) represents the charging work of cable normal condition；Represent to connect with red LED Device head becomes big because of micro-short circuit or contact impedance so that connector inner heat, stops power supply.It can be come using the first cut-off signals Control green LED and red LED；The effective time point shiny red LED of first cut-off signals, the invalid time point bright green of the first cut-off signals LED。

As shown in figure 5, charge cable and terminal are linked together by USB connector.In this scenario, can charge Cable and terminal two parts set detection circuit to be used for the voltage for detecting USB connector power pins both ends respectively, according to detection Magnitude of voltage can calculate the voltage differences of connector power pins, combined charge electric current, power supply in USB connector can be calculated The contact impedance change of pin.It is adapted to adjust charging current according to impedance variations, and passes it to terminal and remind user Charge cable is connected with terminal in the presence of abnormal.

When the voltage of detection electric circuit inspection to the terminal side USB connector power pins of terminal is close or equal to reference Level or 0 level, show that power pins have short trouble in USB connector.When the impedance detected is general more than connector It the default impedance threshold normally connected, can empirically be worth reduction charging current, ensure that charge cable is transferred to the electricity of terminal Pressure meets VBUS charging specifications.

The circuit protection circuit that the utility model embodiment provides can detect circuit with voltage connector and combine, parallel work Make further protection cable.Before can be used for thoroughly protection open circuit, charger ensures to fill according to contact impedance adjustment output current The continuity of electric process.In the charge cable of TYPE C specifications, part work can combine e-marker chips to realize.

Good effect caused by the utility model is described in further detail with reference to specific example；

A kind of as shown in fig. 6, typical circuit figure that the utility model embodiment provides；The first switch circuit 13 wraps Include：First metal-oxide-semiconductor Q1, the first triode Q2, first resistor R1, wherein, the source electrode of the Q1 is the first switch circuit Input, Q1 grid is connected with the colelctor electrode of the first triode is used as the second control terminal, and Q2 base stage and R2 one end connect As the first switch control terminal of the first switch circuit 13, Q2 emitter stage and the R1 other end are connected and are grounded, described Q1 drain electrode is the output end of the first switch circuit 13；Q1 is P-channel field-effect transistor (PEFT) pipe, Q1 grids be additionally provided with NOT gate be used for it is real Existing negative function；Q2 is NPN triode.First power on detection circuit includes：Second resistance R1, R1 one end and Q1 source electrodes Connection, the R1 other ends are connected the connection end as the second switch control terminal of first switch circuit 13, R2 and Q2 with Q1 grids It may be considered the conducting control terminal of the first power on detection circuit 14；R1, Q2 and M cooperate and realize the first power on detection circuit 14 function；RT is self- recoverage protection circuit 11；D and M forms the first monitoring for protection circuit 12；Wherein, M is touched by d type flip flop etc. The control circuit such as Power Generation Road or single-chip microcomputer is realized；Q1 can be an integrated PMOS, and a reverse work(is carried in grid Can, when M exports low level, Q1 conductings；When M exports high level, Q1 cut-offs；Wherein, the of the first switch circuit 13 It one switch control terminal and second switch control terminal, can be same interface, first can be determined by priority level setting On-off circuit 13 is carried out the switchable control of electric current by the control of the first power on detection circuit 14 or the first monitoring for protection circuit 12.

When VBUS is upper electric, VBUS is by resistance R1, and instead back into Q1 grid, Q2 acquiescences when upper electric are not turned on shape State, now Q1 conductings, first flows to electric current is powered by Q1 to connector.

When connector breaks down adstante febre, the rise of RT resistance, when RT both end voltages increase, diode D conducting Pressure drop is the threshold value of temperature protection, and M controls the base stage of Q2 in first switch circuit 13 according to the pressure drop, opens Q2, from and then Close Q1 and cut off VBUS to connector power supply；M persistently detects VBUS, if VBUS is persistently kept, persistently opens Q2, closes Q1, VBUS is kept to be off with connector.

Only when user is found that failure situation, cut-out VBUS power supplies, to circuit protection circuit replacement, and again to VBUS Electricity is carried out, the circuit protection circuit can just reopen supply access.

For the embodiment described in Fig. 3, using in Fig. 6 circuit implementation process, self- recoverage protection circuit can be shared RT, implement using with the first monitoring for protection circuit 12, the identical circuit of 13 and first power on detection circuit of first switch circuit 14 Mode realizes the second monitoring for protection circuit 15, the power on detection circuit 17 of second switch circuit 16 and second；

The second switch circuit 16 can include：Second metal-oxide-semiconductor, the second triode, 3rd resistor, wherein, the 2nd MOS Input of the pipe source electrode as the second switch circuit, the second metal-oxide-semiconductor grid are connected conduct with the colelctor electrode of the second triode Second control terminal, one end connection of the base stage and 3rd resistor of the second triode are opened as the first of the second switch circuit 16 Control terminal is closed, the emitter stage of the second triode and the other end of 3rd resistor are connected and be grounded, and the drain electrode of second metal-oxide-semiconductor is The output end of the first switch circuit 16；Wherein, second metal-oxide-semiconductor is P-channel field-effect transistor (PEFT) pipe, the second metal-oxide-semiconductor grid Pole is additionally provided with NOT gate；Second triode is NPN triode；Second power on detection circuit 17 can include：4th electricity Resistance, described 4th resistance one end are connected with the second metal-oxide-semiconductor source electrode, and the other end is connected with the second metal-oxide-semiconductor grid.Using second group of D The second monitoring for protection circuit 12 is formed with M；

In this way, when flowing to electric current in circuit for first, by self- recoverage protection circuit 11, the first monitoring for protection circuit 12, the One on-off circuit 13 and the protection of the implementing circuit of the first power on detection circuit 14；When flowing to electric current in circuit for second, by self- recoverage Protection circuit 11, the second monitoring for protection circuit 15, the power on detection circuit 17 of second switch circuit 16 and second are completed circuit and protected Shield.

The line protection method that the utility model embodiment provides, as shown in fig. 7, methods described includes：

Step 701：The first voltage for obtaining the self- recoverage protection circuit both ends that impedance is varied with temperature and changed is poor；

Here, the power cable used during with charge power supply to terminal charge, such as USB cable, exemplified by illustrate that this practicality is new Type embodiment；As described in Figure 1, a circuit protection circuit can be set such as to be arranged in the power line of the power cable In the 5V power lines of USB cable；One self- recoverage protection circuit 11, self- recoverage protection circuit can be set in circuit protection circuit 11 direct impedances are varied with temperature and changed, and can be that direct impedance raises with temperature rise or when temperature reaches Disconnected during preset temperature, high impedance status is presented, and recover channel status when temperature recovers normal temperature；

Self- recoverage protection circuit 11 can be arranged on power line both ends close to connector, as USB connector pin at, Just it is proximate at the power pins of terminal charge interface.When in temperature normal range of operation, the self- recoverage protection circuit 11 is in Existing extremely low impedance, so as to when electric current is by that and will not cause too big pressure drop；Because foreign matter enters or connector at connector The generation micro-short circuit phenomenon of the internal power path caused by plug causes physical damage and other electric paths, charge power supply are given Because micro-short circuit produces heating when terminal is powered；Or the socket and plug of connector causes golden finger surface golden because of long-term plug Category oxidation, produces larger contact impedance, so that connector produces heating because of contact impedance；The self- recoverage protection circuit 11, because of temperature rise in connector, cause impedance to raise；Such as connector temperature because power-off or failture evacuation return to safe temperature model Enclose, self- recoverage protection circuit 11 returns to normal operating conditions impedance；The self- recoverage protection circuit is positioned close to connector electricity At the golden finger of source pin, faster to sense change of the connector in electric current by rear temperature.

The self- recoverage protection circuit 11 can use PTC thermistor or Breaker equitemperature protection devices.Such as Fig. 1 In shown circuit block diagram, when first in circuit flows to electric current after self- recoverage protection circuit 11, pass through the power supply of connector Pin is powered to terminal.The input of first switch circuit 13 connection first flows to the affiliated power output end of electric current, the The output end of the one on-off circuit 13 connection input of self- recoverage protection circuit 11, the two of the first monitoring for protection circuit 12 Individual test side is connected with the input and output end of the self- recoverage protection circuit 11 respectively, the first monitoring for protection circuit 12 Control output end be connected with the first switch control terminal of the first switch circuit 13, the self- recoverage protection circuit 11 exports The power pins of end connection connector；Generally, charge power supply connection external power supply, such as civil power etc., charge power supply output charging Electric current.The now power supply on power line can undergo a power up, and the phenomenon showed is charge power supply from zero to fixation The uphill process of magnitude of voltage, such as the change from 0V to 5V.In whole power supply process, the PTC in self- recoverage protection circuit 11 Thermistor or Breaker equitemperatures protection device carry out performance change with the temperature change inside connector；It is once because micro- Connector internal temperature caused by short circuit or contact resistance rises to some threshold value, PTC resistor or Breaker temperature protection devices One of starting protection function, the phenomenon showed are exactly that the current capacity passed through reduces and impedance increase.

In circuit protection circuit one can be set to be directed to the first the first monitoring for protection circuit 12 for flowing to electric current and the One on-off circuit 13, the first monitoring for protection circuit 12 are used to obtain the both ends of self- recoverage protection circuit 11 in the first flow direction electricity The first voltage flowed down is poor, when first voltage difference is beyond the first default protection voltage difference threshold value to first switch electricity Road 13 exports the first cut-off signals；

First monitoring for protection circuit 12 can include the PN junction semiconductor components and devices of one or more one-way conductions, such as two poles Pipe, diode direction is consistent with the first direction of current, in parallel with self- recoverage protection circuit 11, when self- recoverage protection circuit 11 PTC thermistor or Breaker equitemperature protection device normal works when, conducting resistance is very small, caused pressure drop nor Often small, the diode in the first monitoring for protection circuit 12 is not turned on, and the pressure drop at diode both ends is the pressure drop of protection location；When certainly The PTC thermistor or the protection of Breaker equitemperatures protection device for recovering protection circuit 11 are opened, and impedance varies with temperature certain In individual threshold range, the pressure drop is more than or equal to the conduction voltage drop of diode so that diode current flow；Can according to demand, if The forward conduction voltage drop of PN junction semiconductor components and devices is put, i.e. the conduction voltage drop of diode is the first default guarantor of temperature protection Protect voltage difference threshold value.

In practical application, the first monitoring for protection circuit 12 can be triggered by the threshold voltage being made up of discrete component Circuit, the control circuits such as single-chip microcomputer can also be used to realize the function of the monitoring for protection circuit.

Step 702：When first voltage difference is beyond default first protection voltage difference threshold value, the first shut-off letter is sent Number, turn off the electric current that the power supply exports；

Further, the circuit protection circuit includes also including：First power on detection circuit 14；Electric-examination on described first Slowdown monitoring circuit 14 is additionally operable to, when first flows to the affiliated power supply electrifying of electric current, to the conducting of the first switch circuit 13 output first believe Number；The first switch circuit 13, for flowing to electric current according to first Continuity signal conducting described first；On described first The upper electro-detection end of power detection circuit 14 flows to the affiliated power output end of electric current with first and is connected, first power on detection circuit 14 conducting control terminal is connected with the second switch control terminal of the first switch circuit 13.

In some usage scenarios, such as USB type C power line, two terminal adapters of the power line are complete one Sample, position can exchange for charge power supply and terminal opposed power line, and therefore, the direction that electric current flows on the power line can Can meeting on the contrary, relative to the first of principle flow to electric current have a flow direction conversely second flow to electric current；Such as USB type C power line has two identical connectors 1 and connector 2, when connector 1 is connected to charger, sense of current From connector 1 to connector 2, to be properly termed as first and flowing to electric current, when connector 2 is connected to charger, sense of current From connector 2 to interface 1, to be properly termed as second and flowing to electric current；At this moment, can be with as shown in Fig. 2 can be in two inverse currents Two groups of identical circuit protection circuits in parallel on the circuit that can be flowed through；The direction of setting is corresponding with electric current；Positive route protection Circuit is used for circuit during protective current forward flow, ends during reverse direction current flow；Reverse circuit protection circuit is used to protect Circuit during reverse direction current flow is protected, is ended during electric current forward flow.

The power cable that the utility model embodiment provides, is connected by connector with power supply or power receiving equipment；The confession Electric wire cable includes circuit protection circuit.The cable includes：Circuit protection circuit；As shown in figure 1, the circuit protection circuit bag Include：The self- recoverage protection electricity that first monitoring for protection circuit 12, first switch circuit 13 and direct impedance are varied with temperature and changed Road 11；

Here, the power cable used during with charge power supply to terminal charge, such as USB cable, exemplified by illustrate that this practicality is new Type embodiment；The circuit protection circuit can be arranged in the power line of the power cable, be such as arranged on the 5V of USB cable In power line；The direct impedance of self- recoverage protection circuit 11 is varied with temperature and changed, and can be direct impedance with temperature liter It is high and raise or disconnected when temperature reaches preset temperature, high impedance status is presented, and recover normal temperature in temperature Shi Huifu channel status；

As shown in figure 8, the circuit protection circuit can be arranged at the link position of the cable and the connector, such as On the circuit board that connector connects with cable；Self- recoverage protection circuit 11 can be arranged on power line both ends close to connector, such as At the pin of USB connector, that is, at the power pins of terminal charge interface.When in temperature normal range of operation, institute State self- recoverage protection circuit 11 and extremely low impedance is presented, so as to when electric current is by that and will not cause too big pressure drop；Work as connector The generation of place power path and other electric paths caused by plug causes physical damage inside foreign matter entrance or connector Micro-short circuit phenomenon, because micro-short circuit produces heating when charge power supply is powered to terminal；Or the socket and plug of connector is because long-term Plug, causes golden finger surface metal oxidization, produces larger contact impedance, so that connector produces hair because of contact impedance Heat；The self- recoverage protection circuit 11 causes impedance to raise because of temperature rise in connector；As connector temperature because power-off or therefore Barrier exclusion returns to safe temperature range, and self- recoverage protection circuit returns to normal operating conditions impedance；The self- recoverage protection circuit 11 are positioned close at the golden finger of connector power pins, faster to sense change of the connector in electric current by rear temperature Change.

The self- recoverage protection circuit 11 can use PTC thermistor or Breaker equitemperature protection devices.Such as Fig. 1 Shown, first flows to electric current after first switch circuit 13 and self- recoverage protection circuit 11, is given by the power pins of connector Terminal is powered.The input of first switch circuit 13 connection first flows to the affiliated power output end of electric current, first switch The output end of circuit 13 connects the input of self- recoverage protection circuit 11, two test sides of the first monitoring for protection circuit 12 It is connected respectively with the input and output end of the self- recoverage protection circuit 11, the control of the first monitoring for protection circuit 12 Output end is connected with the first switch control terminal of the first switch circuit 13, the output end of self- recoverage protection circuit 11 connection The power pins of connector；Generally, charge power supply connection external power supply, such as civil power etc., charge power supply output charging current.This When power line on power supply can undergo a power up, the phenomenon showed is charge power supply from zero to fixed voltage value Uphill process, such as the change from 0V to 5V.Charging current passes through first switch circuit 13, self- recoverage protection circuit 11 and connection The power pins of device, it is possible to allow power supply to be output to terminal.In whole power supply process, the PTC in self- recoverage protection circuit 11 Thermistor or Breaker equitemperatures protection device carry out performance change with the temperature change inside connector；It is once because micro- Connector internal temperature caused by short circuit or contact resistance rises to some threshold value, PTC resistor or Breaker temperature protection devices One of starting protection function, the phenomenon showed are exactly that the current capacity passed through reduces and impedance increase.

In practical application, the first monitoring for protection circuit 12 can be triggered by the threshold voltage being made up of discrete component Circuit, the control circuits such as single-chip microcomputer can also be used to realize the function of the first monitoring for protection circuit 12.

In some usage scenarios, such as USB type C power line, two terminal adapters of the power line are complete one Sample, position can exchange for charge power supply and terminal opposed power line, and therefore, the direction that electric current flows on the power line can Can meeting on the contrary, relative to original first flow to electric current have a flow direction conversely second flow to electric current；Such as USB type C power line has two identical connectors 1 and connector 2, when connector 1 is connected to charger, sense of current From connector 1 to connector 2, to be properly termed as first and flowing to electric current, when connector 2 is connected to charger, sense of current From connector 2 to interface 1, to be properly termed as second and flowing to electric current；At this moment, can be on the circuit that two inverse currents can flow through In the same direction or reverse parallel connection sets two groups of identical circuit protection circuits, is respectively used to protection first and flows to electric current and the second flow direction electricity Stream；The method that reverse parallel connection is set can be with as shown in Fig. 2 the direction of protection circuit setting be corresponding with electric current；Positive circuit is protected Protection circuit is used for circuit during protective current forward flow, ends during reverse direction current flow；Reverse circuit protection circuit is used for Circuit during protective current reverse flow, end during electric current forward flow.

When electric current be first flow to electric current when, by self- recoverage protection circuit 11, first switch circuit 13, electro-detection on first The monitoring for protection circuit 12 of circuit 14 and first is protected to connector；When electric current flows to electric current for second, protected by self- recoverage Protection circuit 11, second switch circuit 16, the second power on detection circuit 17 and the second monitoring for protection circuit 15 are protected to connector Shield.The second monitoring for protection circuit 15 obtains the both ends of self- recoverage protection circuit 11 and flows to the second electricity under electric current second Pressure difference, when second voltage difference is beyond the second default protection voltage difference threshold value to the second switch circuit 16 input second Cut-off signals；Wherein, the first default protection voltage difference threshold value and the second default protection voltage difference threshold value can be with identical；Described second On-off circuit 16, described second is turned off when receiving second cut-off signals and flows to electric current；The second monitoring for protection circuit Second cut-off signals of 15 outputs make the second open-end circuit 16 be always maintained at turning off, and until user's shut-off charge power supply, make whole Circuit restoration, it could be turned on again after re-powering；Second power on detection circuit 17, electric current institute is flowed to for detecting second Belong to the power-up state of power supply, described second flows to electric current affiliated power supply when persistently keeping power supply state, locks the overheat protector Signal, keep the off state of second switch circuit 16；Second power on detection circuit 17, the affiliated power supply of electric current is flowed to second When upper electric, the second Continuity signal is exported to the second switch circuit 16；The second switch circuit 16, led according to described second Messenger conducting described second flows to electric current；The upper electro-detection end of second power on detection circuit 17 and second flows to electric current institute Belong to power output end connection, the conducting control terminal of second power on detection circuit 17 and the second of the second switch circuit 16 Switch control terminal connects.

As shown in figure 4, in practical application, in circuit when second flows to, the output that can be generally connected by connector is electric Source carries out output current protection, therefore, can eliminate the self- recoverage defencive function of the second direction of current, use second Substituted to current path circuit.Second to flow to current path circuit be to ensure the one-way of power path, while can be protected Demonstrate,prove the Consumer's Experience of cable.Such as when the cable is TYPE-C charge cable, input/output terminal minor structure is the same, connection Device role can redefine on demand.Second flows to the path that current path circuit can be an one-way conduction, such as Single-way switch circuit being made up of metal-oxide-semiconductor etc. etc..

In practical application, configured information can be provided and be used to identify the cable working condition in work.Such as use green LED Represent the charging work of cable normal condition；Represent that connector head becomes big because of micro-short circuit or contact impedance with red LED so that connection Device inner heat, stops power supply.Green LED and red LED can be controlled using the first cut-off signals；First cut-off signals have Imitate time point shiny red LED, the invalid time point bright green LED of the first cut-off signals.

As shown in figure 5, charge cable and terminal are linked together by USB connector.In this scenario, can charge Cable and terminal two parts set detection circuit to be used for the voltage for detecting USB connector power pins both ends respectively, according to detection Magnitude of voltage can calculate the voltage differences of connector power pins, combined charge electric current, power supply in USB connector can be calculated The contact impedance change of pin.It is adapted to adjust charging current according to impedance variations, and passes it to terminal and remind user Charge cable is connected with terminal in the presence of abnormal.When the detection electric circuit inspection of terminal is to terminal side USB connector power pins Voltage is close or equal to datum or 0 level, shows that power pins have short trouble in USB connector.When detecting Impedance be more than the default impedance threshold that normally connects of connector, can empirically be worth reduction charging current, ensure to fill The voltage that electric wire cable is transferred to terminal meets VBUS charging specifications.The circuit protection circuit that the utility model embodiment provides can To be combined with voltage connector detection circuit, cable is further protected in concurrent working.Before can be used for thoroughly protection open circuit, charging Device ensures the continuity of charging process according to contact impedance adjustment output current.In the charge cable of TYPE C specifications, the part Work can combine e-marker chips to realize.

When the circuit protection circuit is arranged in the service cable, the circuit protection circuit can be arranged on In one terminal adapter of service cable, the circuit protection circuit can also be respectively provided with the connector at service cable both ends； Two groups of in the same direction or reverse parallel connection setting circuit protection circuits can be respectively set at both ends, reverse parallel connection circuit is respectively provided with both ends The mode of protection circuit can as illustrated in fig. 9, and the power cable has the first connector and the second connector, and positive line Road protection circuit A, positive circuit protection circuit B, reverse circuit protection circuit C and reverse circuit protection circuit D.Wherein positive line Road protection circuit A and reverse circuit protection circuit C is arranged on the connecting portion of the first connector, the protection for the first connector； Positive circuit protection circuit B and reverse circuit protection circuit D is arranged on the connecting portion of the second connector, for the first connector Protection；When the first connector connects power supply, the current trend in power cable flows to the trend of electric current for first in figure, Now, positive circuit protection circuit A and positive circuit protection circuit B work, protects the first connector and the second connector respectively； When the second connector connects power supply, the current trend in power cable flows to the trend of electric current for second in figure, now, Reverse circuit protection circuit C and reverse circuit protection circuit D work, protects the first connector and the second connector respectively；Two End is respectively provided with parallel line protection circuit mode in the same direction can as shown in figure 9b, the circuit protection circuit described in Fig. 1 to Fig. 6 The one or both ends of power cable are arranged on, will not be repeated here.

It is described above, most preferred embodiment only of the present utility model, it is not intended to limit protection of the present utility model Scope, all made within spirit of the present utility model and principle all any modification, equivalent and improvement etc., should be included in Within the scope of protection of the utility model.

Claims

1. a kind of circuit protection circuit, it is characterised in that the circuit includes：

It is poor to obtain the first voltage at the self- recoverage protection circuit both ends, and in first voltage difference beyond the first default protection To the first monitoring for protection circuit of the cut-off signals of first switch circuit output first during voltage difference threshold value；

One end of the first switch circuit connects one end of the self- recoverage protection circuit, the first monitoring for protection circuit Both ends of two test sides respectively with the self- recoverage protection circuit are connected, the control output end of the first monitoring for protection circuit It is connected with the first switch control terminal of the first switch circuit.

2. circuit according to claim 1, it is characterised in that the circuit also includes：

It is poor to obtain the second voltage at the self- recoverage protection circuit both ends, and in second voltage difference beyond the second default protection The second monitoring for protection circuit of the second cut-off signals is inputted during voltage difference threshold value to second switch circuit；

One end of the second switch circuit connects one end of the self- recoverage protection circuit, the second monitoring for protection circuit Both ends of two test sides respectively with the self- recoverage protection circuit are connected, the control output end of the second monitoring for protection circuit It is connected with the first switch control terminal of the second switch circuit.

3. circuit according to claim 1, it is characterised in that the circuit also includes：

Power supply electrifying state is detected, in the power supply electrifying to the Continuity signal of first switch circuit output first instruction the One on-off circuit turns on the first power on detection circuit of the output current of the power supply；

The upper electro-detection end of first power on detection circuit is connected with power output end, and first power on detection circuit is led Logical control terminal is connected with the second switch control terminal of the first switch circuit.

4. circuit according to claim 2, it is characterised in that the circuit also includes：

Power supply electrifying state is detected, in the power supply electrifying to the Continuity signal of second switch circuit output second instruction the Two on-off circuits turn on the second power on detection circuit of the output current of the power supply；

The upper electro-detection end of second power on detection circuit is connected with power output end, and second power on detection circuit is led Logical control terminal is connected with the second switch control terminal of the second switch circuit.

5. the circuit according to claim 1 or 4, it is characterised in that the circuit protection circuit has two, and in the same direction or anti- To being arranged in parallel.

6. circuit according to claim 5, it is characterised in that described two circuits are replaced using the path of one-way conduction and protected One in protection circuit.

7. according to the circuit described in any one of Claims 1-4, it is characterised in that the self- recoverage protection circuit be arranged at by The heating position of protection circuit.

8. according to the circuit described in any one of Claims 1-4, it is characterised in that the first monitoring for protection circuit includes：With The more than one PN junction semiconductor components and devices that the self- recoverage protection circuit is arranged in parallel in the same direction；

9. circuit according to claim 3, it is characterised in that the first switch circuit includes：First metal-oxide-semiconductor, first Triode, first resistor, wherein, the grid of first metal-oxide-semiconductor is connected with the colelctor electrode of the first triode as the second control End, the base stage of the first triode and one end of first resistor connect the first switch control terminal as the first switch circuit, The emitter stage of first triode and the other end of first resistor are connected and are grounded.

10. circuit according to claim 9, it is characterised in that first metal-oxide-semiconductor is P-channel field-effect transistor (PEFT) pipe, described One metal-oxide-semiconductor grid is additionally provided with NOT gate；First triode is NPN triode.

11. circuit according to claim 9, it is characterised in that first power on detection circuit includes：Second resistance, Described second resistance one end is connected with the first metal-oxide-semiconductor source electrode, and the other end is connected with the first metal-oxide-semiconductor grid.

12. the circuit according to claim 2 or 4, it is characterised in that the second monitoring for protection circuit includes：With it is described The more than one PN junction semiconductor components and devices that self- recoverage protection circuit is arranged in parallel in the same direction；

13. circuit according to claim 4, it is characterised in that the second switch circuit includes：Second metal-oxide-semiconductor, second Triode, 3rd resistor, wherein, input of the second metal-oxide-semiconductor source electrode as the second switch circuit, the second metal-oxide-semiconductor grid It is connected with the colelctor electrode of the second triode and is used as the second control terminal, one end connection of the base stage and 3rd resistor of the second triode is made For the first switch control terminal of the second switch circuit, the emitter stage of the second triode and the other end connection of 3rd resistor are simultaneously Ground connection, the drain electrode of second metal-oxide-semiconductor are the output end of the first switch circuit.

14. circuit according to claim 13, it is characterised in that second metal-oxide-semiconductor is P-channel field-effect transistor (PEFT) pipe, described Second metal-oxide-semiconductor grid is additionally provided with NOT gate；Second triode is NPN triode.

15. circuit according to claim 14, it is characterised in that second power on detection circuit includes：4th resistance, Described 4th resistance one end is connected with the second metal-oxide-semiconductor source electrode, and the other end is connected with the second metal-oxide-semiconductor grid.

16. a kind of power cable, it is connected by connector with power supply or power receiving equipment；Characterized in that, the power cable bag Include the circuit protection circuit described in any one of claim 1 to 15.

17. power cable according to claim 16, it is characterised in that the circuit protection circuit is arranged at the power supply The link position of cable and the connector.

18. the power cable according to claim 16 or 17, it is characterised in that the circuit protection circuit is respectively arranged at Power cable both ends and the link position of the connector.