CN108418189A - Switch protecting circuit - Google Patents
Switch protecting circuit Download PDFInfo
- Publication number
- CN108418189A CN108418189A CN201810091133.2A CN201810091133A CN108418189A CN 108418189 A CN108418189 A CN 108418189A CN 201810091133 A CN201810091133 A CN 201810091133A CN 108418189 A CN108418189 A CN 108418189A
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- Prior art keywords
- switch
- diode
- resistance
- circuit
- lower edge
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
- H02H7/222—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices for switches
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
- H03K17/081—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit
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Abstract
The present invention provides a kind of switch protecting circuit, the switch protecting circuit include rapidly switch off circuit and controllable switch, wherein：The circuit that rapidly switches off includes the first diode, the second diode, 3rd resistor, the 4th resistance and the second capacitance, the anode of first diode connects the anode of second diode and the first end of the 4th resistance, the second end of 4th resistance connects the output end of a lower edge switch, the cathode of first diode couples the input terminal of the lower edge switch, the cathode of second diode connects the input terminal of the controllable switch, and the output end of the controllable switch connects the input terminal of the lower edge switch；Described 3rd resistor one end connects the cathode of second diode, other end ground connection；Second capacitance one end connects the first end of the 4th resistance, other end ground connection.
Description
Technical field
The present invention relates to analog electronics technique field, more particularly to a kind of switch protecting circuit.
Background technology
Fig. 1~2 are respectively switching mode and the low side driver circuit schematic diagram of PWM types, the two mainly by low side driving circuit and
Two parts of diagnostic circuit form.Low side driving circuit is when the switching signal or pwm signal S1 of master controller output are height
Level, when being provided to the input terminal 11 of switch K1, the load end 12 of switch K1 is connected over the ground, and 10 one end of load connect power supply
Vbat, the other end 13 is since ground connection, load 10 are provided power, when S1 is low level, the K1 load ends 12 of switch with
GND is disconnected, and switch K1 is during be conducting to disconnection, side circuit low for switching mode shown in FIG. 1, if load 10 is to feel
Property load, then needing lower edge switch clamper absorption inductor energy, (if lower edge switch ability not enough needs additional TVS, auxiliary is protected
Shield), until electric current is reduced to zero；Side circuit low for PWM types shown in Fig. 2, load 10 are typically all inductive load, at this time can be with
By diode D100 afterflows, ensure that electric current will not be mutated.C1 is ESD Absorption Capacitances.
The failure of low side driving circuit mainly has SCB (load end 13 is shorted to power supply), the SCG (load ends 13
It is shorted to ground) and OL (open circuit of the load end 13), for different switch fault states, diagnostic requirements are also different.
The diagnosis on low side is connected to node 12 using the AD mouths or I/O port of MCU by resistance, and Diagnostic Strategy is by judging MCU
AD mouths or I/O port sampled voltage.For the switching mode in Fig. 1, when low side driving circuit switch K1 is disconnected, pass through signal S4
Voltage is provided to master controller, and master controller diagnoses low side SCG failures and OL failure (fault-frees according to the voltage magnitude of signal S4
When two resistance of the S4 between node 12 and ground to the partial pressure value of Vbat；If it is be shorted to ground, the low electricity that S4 is close to zero
It is flat；If it is open circuit, S4 is partial pressure value of three resistance to VDD)；When lower edge switch K1 conductings, pass through the ports master controller S4
(S4 amplitudes should be the low level close to ground at this time, but the load end 12 is shorted to power supply makes S4 for diagnosable low side SCB failures
For a branch pressure voltage).For the PWM types in Fig. 2, when low side driving circuit OFF state, i.e., low side driving circuit switch K1 is disconnected
After (loading the not switch off state in afterflow), master controller is provided to by signal S4 current potentials, master controller is according to letter
The low side SCG failures of potential diagnostic and OL failures of number S4；Lower edge switch K1 conducting (low side driving circuit PWM state, i.e. K1 according to
Certain rule is alternately closed and shutdown) when, pass through SCB failures, the SCG failures of the diagnosable low side output in the ports master controller S4
With OL failures.Judge that the I/O port of MCU continues the low and high level variation of several PWM cycles to determine whether faulty presence.When adopting
When having low and high level variation in the sample period, it is judged as normal condition；If I/O port level is when continuing high, to be judged as in the sampling period
SCB failures occur；If I/O port level is when continuing low to be judged as that SCG failures or OL failures (SCG and OL occurs in the sampling period
Two failures cannot be distinguished).
Damage of the SCB failures to master controller in this three classes failure when low side conducting state is maximum, if really occurring
When SCB failures, diagnosis acknowledging time, which is several milliseconds of even a few tens of milliseconds, short circuit currents during which, can reach tens of amperes, millisecond
Heavy current impact more than rank has following risk：Lower edge switch is burnt out, PCB trace is burnt out, is more than functional safety institute
It is required that other security risk problems for being caused of turn-off time.So for current Diagnostic Strategy, fault recognition and shutdown
Timeliness it is very poor, have damage controller risk.
Invention content
The purpose of the present invention is to provide a kind of switch protecting circuits, are shorted to solving existing lower edge switch output end
The problem of power failure diagnosing overlong time.
In order to solve the above technical problems, the present invention provides a kind of switch protecting circuit, the switch protecting circuit includes fast
Fast breaking circuit and controllable switch, wherein：
The circuit that rapidly switches off includes the first diode, the second diode, 3rd resistor, the 4th resistance and the second electricity
Hold, the anode of first diode connects the anode of second diode and the first end of the 4th resistance, described
The second end of 4th resistance connects the output end of a lower edge switch, and the cathode of first diode couples the lower edge switch
The cathode of input terminal, second diode connects the input terminal of the controllable switch, the output end connection of the controllable switch
The input terminal of the lower edge switch；
Described 3rd resistor one end connects the cathode of second diode, other end ground connection；
Second capacitance is in parallel with the 3rd resistor.
Optionally, in the switch protecting circuit,
One first control signal is provided to the input terminal of the lower edge switch, and the first control signal is the first level
When, the output end of the lower edge switch is second electrical level, when the first control signal is second electrical level, the lower edge switch
Output end is grounded, wherein the first level is less than second electrical level.
Optionally, in the switch protecting circuit, when the controllable switch disconnects, the output of the controllable switch
For high-impedance state, when the controllable switch is closed, the output end of the controllable switch is grounded；
It is described when the first control signal is located at second electrical level for the second end of second electrical level and the 4th resistance
Second diode current flow, the controllable switch are closed；
It is described when the first control signal is located at second electrical level for the second end of the first level and the 4th resistance
Second diode turns off, and the controllable switch disconnects；
It is described when the first control signal is located at the first level for the second end of second electrical level and the 4th resistance
Second diode turns off, and the controllable switch disconnects.
Optionally, in the switch protecting circuit, one load of switch protecting circuit connection, the of the load
One end connects main power source, and the second end of the load connects the output end of the lower edge switch by the first capacity earth；
The switch protecting circuit further includes second resistance, one end input the first control letter of the second resistance
Number, the other end connects the input terminal of the lower edge switch.
Optionally, in the switch protecting circuit, the circuit that rapidly switches off further includes AND gate circuit, wherein：
One second control signal is provided to the first input end of the AND gate circuit；Second input terminal of the AND gate circuit
Connect the cathode of second diode；The output end of the AND gate circuit couples the input terminal of the controllable switch.
Optionally, in the switch protecting circuit, the first control signal is pulse-width signal.
Optionally, in the switch protecting circuit, the load further includes the 6th diode, the 6th diode
Anode connect the second end of the load, the cathode of the 6th diode connects the main power source.
Optionally, in the switch protecting circuit, the circuit that rapidly switches off further includes the 5th resistance, the 6th electricity
Resistance, third diode, the 4th diode and the 5th diode, wherein：
The both ends of 5th resistance are separately connected the input terminal of the output end and the controllable switch of the AND gate circuit；
The both ends of 6th resistance be separately connected the lower edge switch output end and the AND gate circuit it is first defeated
Enter end；
The anode of the third diode connects the output end of the AND gate circuit, the cathode connection of the third diode
Second input terminal of the AND gate circuit；
The anode of 4th diode connects the first input end of the AND gate circuit, the cathode of the 4th diode
Connect a constant pressure source；
The anode of 5th diode connects the first input end of the AND gate circuit, the cathode of the 5th diode
Input the second control signal.
Optionally, in the switch protecting circuit, second capacitance, 3rd resistor, the 4th resistance and the two or two
The selection of pole pipe should meet t and be more than the lower edge switch closing course time, wherein：
Wherein, R=R3*R4/ (R3+R4), Ut=Vth, U0=0V, Us=(Vbat-Vf) * R3/ (R3+R4), if
(Vbat-Vf) * R3/ (R3+R4) >=5V, then US=5V, wherein：Vth is the cut-in voltage of the controllable switch or described and door
The high-level threshold voltage of circuit, Vbat are main supply voltage value, and Vf is the conduction voltage drop of the second diode, and R3 is 3rd resistor
Resistance value, R4 be the 4th resistance resistance value, C be the second capacitance capacitance.
Optionally, in the switch protecting circuit, the electric conduction of first diode and second diode
It presses equal.
In switch protecting circuit provided by the invention, the anode of the first diode connects the anode of second diode
And the 4th resistance first end, the 4th resistance second end connection lower edge switch output end, first diode
Cathode coupling lower edge switch input terminal, the cathode of second diode connects the input terminal of the controllable switch, and (Fig. 3 is fast
Fast breaking circuit) or the connection AND gate circuit the second input terminal (Fig. 4 rapidly switches off circuit), the output of the controllable switch
End connects the input terminal of the lower edge switch, and when there are SCB failures, i.e., the input terminal of lower edge switch is high level, and low side is opened
But it is high level when the output end of pass should be low level, C2 is started to charge up at this time, until charging to opening for the input terminal more than K2
When opening high-level threshold (Fig. 4 rapidly switches off circuit) of threshold value (Fig. 3 rapidly switches off circuit) or the second input terminal of U1, controllably open
Pass is opened, and further makes lower edge switch input terminal approximately ground, and heavy current impact leads to TCU's caused by preventing SCB failures
Damage.
Further, by the setting to AND gate circuit, second control signal can be increased, to the switch after troubleshooting
Protection circuit is resetted.
The present invention by increase based on controllable switch low side output rapidly switch off circuit after, for the SCB in work
Fault diagnosis processing shorten to Microsecond grade by Millisecond, avoids the damage to controller, while can also meet ISO26262 work(
The strict demand of energy safety.
Description of the drawings
Fig. 1~2 are existing lower edge switch drive circuit schematic diagrams；
Fig. 3 is one embodiment of the invention lower edge switch drive circuit schematic diagram；
Fig. 4 is another embodiment of the present invention lower edge switch drive circuit schematic diagram.
Specific implementation mode
Switch protecting circuit proposed by the present invention is described in further detail below in conjunction with the drawings and specific embodiments.Root
According to following explanation and claims, advantages and features of the invention will become apparent from.It should be noted that attached drawing be all made of it is very simple
The form of change and use non-accurate ratio, only for the purpose of facilitating and clarifying the purpose of the embodiments of the invention.
Core of the invention thought is to provide a kind of switch protecting circuit, short to solve existing lower edge switch output end
The problem of road is to power failure diagnosing overlong time.
To realize above-mentioned thought, the present invention provides a kind of switch protecting circuit, the switch protecting circuit includes quick
Breaking circuit and controllable switch, wherein：The circuit that rapidly switches off includes the first diode, the second diode, 3rd resistor, the
The anode of four resistance and the second capacitance, first diode connects the anode of second diode and the 4th resistance
First end, the second end of the 4th resistance connects the output end of a lower edge switch, the cathode coupling of first diode
The input terminal of the lower edge switch, the cathode of second diode connects the input terminal of the controllable switch, and (Fig. 3 is rapidly switched off
Circuit) or the connection AND gate circuit the second input terminal (Fig. 4 rapidly switches off circuit), the output end connection of the controllable switch
The input terminal of the lower edge switch；Described 3rd resistor one end connects the cathode of second diode, other end ground connection；It is described
Second capacitance is in parallel with the 3rd resistor.
The present embodiment provides a kind of switch protecting circuits, as shown in figure 3, the switch protecting circuit includes rapidly switching off electricity
Road and controllable switch K2, wherein：It is described rapidly switch off circuit include the first diode D1, the second diode D2,3rd resistor R3,
The anode of 4th resistance R4 and the second capacitance C2, the first diode D1 connect anode and the institute of the second diode D2
State the first end of the 4th resistance R4, the second end of the 4th resistance R4 connects the output end 12 of a lower edge switch K1, and described the
The cathode of one diode D1 couples the input terminal 11 of the lower edge switch K1, i.e., the input terminal of lower edge switch K1 is connected to by R2
The cathode of 11, the second diode D2 connect the input terminal of the controllable switch K2, and the output end of the controllable switch K2 connects
The input terminal 11 of the lower edge switch K1 is connect, the one end the 3rd resistor R3 connects the cathode of the second diode D2, another
End ground connection；Second capacitance is in parallel with the 3rd resistor.
Specifically, in the switch protecting circuit, a first control signal S1 is provided to the lower edge switch K1's
Input terminal 11, when the first control signal S1 is the first level, the output end 12 of the lower edge switch K1 is second electrical level, institute
When to state first control signal S1 be second electrical level, the output end 12 of the lower edge switch K1 is grounded, wherein the first level is less than the
Two level.Second electrical level in the present embodiment refers to the value of high level, such as the value of VDD, about 5V or so or Vbat, about 9~
16V or so, the first level refer to 0V or ground connection.When the controllable switch K2 is disconnected, the output of the controllable switch K2 is high resistant
The input terminal 11 of state, lower edge switch K1 keeps primary voltage, when the controllable switch K2 is closed, the output of the controllable switch K2
The input terminal 11 of end ground connection, lower edge switch K1 is grounded；High-impedance state is the generic term in digital circuit, refers to a kind of output of circuit
State, neither high level is nor low level, high-impedance state has no effect to the next stage circuit that it is connected, if using general-purpose
Table measures its current potential, then its current potential is determined by the current potential of next stage circuit.
It (is somebody's turn to do when the first control signal S1 is located at second electrical level for the second end of second electrical level and the 4th resistance R4
Current potential should be the first level, but due to there are SCB failures, is shorted to power supply at this, second electrical level occurs) when, described second
Diode D2 conductings, the controllable switch K2 are closed, the output end ground connection of the controllable switch K2, the input terminal of lower edge switch K1
11 ground connection, even if the output end 12 of lower edge switch K1 is shorted to power supply at this time, also due to input terminal 11 has been turned off, it will not be to control
Device impacts；
When the first control signal S1 is located at second electrical level for the second end of the first level and the 4th resistance R4,
Second diode D2 shutdown, the controllable switch K2 are disconnected, which is that lower edge switch K1 is disconnected and normal situation, can
Control switch K2 will not impact the input terminal of lower edge switch K1；
When the first control signal S1 is located at the first level for the second end of second electrical level and the 4th resistance R,
The second diode D shutdowns, the controllable switch K2 are disconnected, which is the feelings that lower edge switch K1 is closed and works normally
Condition, controllable switch K2 will not impact the input terminal of lower edge switch K1.
Specifically, as shown in figure 3, one load 10 of switch protecting circuit connection, the first end connection of the load 10
Main power source Vbat, the second end of the load 10 connect the output end of the lower edge switch K1 by the first capacitance C1 ground connection
12；The switch protecting circuit further includes second resistance R2, and one end of the second resistance R2 inputs the first control signal
S1, the other end connect the input terminal 11 of the lower edge switch K1.The first control signal S1 is output permanent High level at this time
Or continue low level switching signal.
Further, it as shown in figure 4, the present invention also provides the switch protecting circuit of another embodiment, is opened in described
It closing in protection circuit, the circuit that rapidly switches off further includes AND gate circuit U1, wherein：One second control signal S2 is provided to described
The first input end of AND gate circuit U1；The second input terminal of the AND gate circuit U1 connects the cathode of the second diode D2；
The output end of the AND gate circuit U1 couples the input terminal of the controllable switch K2, i.e., is connected to the controllable switch K2 by R5
Input terminal.The first control signal S1 is pulse-width signal at this time.
Specifically, the load is also connected with one the 6th diode D6, the anode connection of the 6th diode D6 is described negative
10 second end is carried, the cathode of the 6th diode D6 connects the main power source Vbat.The one end second capacitance C2 connection
The second input terminal of the AND gate circuit U1, other end ground connection.The circuit that rapidly switches off further includes the 5th resistance R5, the 6th electricity
R6, third diode D3, the 4th diode D4 and the 5th diode D5 are hindered, wherein：The both ends of the 5th resistance R5 connect respectively
Connect the input terminal of the output end and the controllable switch K2 of the AND gate circuit U1；The both ends of the 6th resistance R6 are separately connected
The first input end of the output end 12 of the lower edge switch K1 and the AND gate circuit U1；The anode of the third diode D3 connects
The output end of the AND gate circuit U1 is connect, the cathode of the third diode D3 connects the second input of the AND gate circuit U1
End, once failure occurs, after output end exports high level, the output end of AND gate circuit is second defeated by it by third diode D3
Enter end to be locked on high level；The anode of the 4th diode D4 connects the first input end of the AND gate circuit U1, described
The cathode of 4th diode D4 connects a constant pressure source VDD and passes through the 4th diode D4's when the current potential of first input end is excessively high
The current potential of clamper, first input end is maintained near power supply vdd voltage, prevents AND gate circuit due to input terminal excessive pressure damages；Institute
The anode for stating the 5th diode D5 connects the first input end of the AND gate circuit U1, the cathode input of the 5th diode D5
The second control signal S2, second control signal S2 keep high level under normal circumstances, when failure and trouble shooting
Afterwards, the second output terminal of master controller is needed to export low level second control signal S2, when second control signal S2 is low electricity
Usually, the current potential of the first input end of AND gate circuit is also low level, and only a diode higher than second control signal S2 is led
Be powered pressure, then AND gate circuit U1 restores to export low level again.
Further, the selection of second capacitance, 3rd resistor, the 4th resistance and the second diode should meet t and be more than
The lower edge switch closing course time, wherein：
Wherein, R=R3*R4/ (R3+R4), Ut=Vth, U0=0V, Us=(Vbat-Vf) * R3/ (R3+R4), if
(Vbat-Vf) * R3/ (R3+R4) >=5V, then US=5V, wherein：Vth is the cut-in voltage of the controllable switch or described and door
The high-level threshold voltage of circuit, Vbat are main supply voltage value, and Vf is the conduction voltage drop of the second diode, and R3 is 3rd resistor
Resistance value, R4 be the 4th resistance resistance value, C be the second capacitance capacitance.
Meeting during the place for being easiest to go wrong in circuit design is lower edge switch K1 drive signals by low get higher
Be not in wrong diagnosis caused by " competition ", " competition " here refers to the output end electricity due to lower edge switch in K1 opening processes
Pressure falls to low level by high level, while capacitance C2 is charged by the current potential of lower edge switch output end, and D1 is caused to be connected with D2
The current potential at place is excessively high, to before K1 closures, be first closed K2 and false triggering K1 rapidly switch off the case where.Specifically, working as K1
When starting to open, S1 is height, and the current potential at node 12 is lower by height, and the cathode of D2 is started to rise to capacitance C2 chargings from 0V
Pressure, charging time seek according to following formula：
T can be found out by above-mentioned formula, the time of lower edge switch conducting can obtain according to corresponding chip data, as long as
Ensure that charge to the time t before controllable switch K2 is opened can avoid due to opening more than the time of lower edge switch opening process experience
The wrong diagnosis problem that " competition " during opening is caused, choosing this time needs there are certain surplus, and this time
It is limited to the conducting voltage Vf of 3rd resistor R3, the 4th resistance R4, the second capacitance C2 and the second diode.
In addition, in the switch protecting circuit, in order to ensure the accurate of circuit, first diode and described
The conducting voltage of two diodes is equal, and when so that S1 being low level, the cathode of D2 is also low level；And S1 be high level when, D2
Cathode be not necessarily low level, specifically to see lower edge switch export situation.
In switch protecting circuit provided in this embodiment, the anode of the first diode D1 connects the second diode D2
Anode and the 4th resistance R4 first end, the output end of the second end connection lower edge switch K1 of the 4th resistance R4, institute
The input terminal of the cathode coupling lower edge switch K1 of the first diode D1 is stated, the cathode connection of second diode is described controllably to open
The input terminal (Fig. 3 rapidly switches off circuit) of pass or the second input terminal (Fig. 4 rapidly switches off circuit) of the connection AND gate circuit, institute
The output end for stating controllable switch K2 connects the input terminal of the lower edge switch K1, when there are SCB failures, i.e. lower edge switch K1's
Input terminal is high level, is but high level when the output end of lower edge switch K1 should be low level, C2 is started to charge up at this time, until filling
When electricity to the unlatching threshold value for the input terminal for being more than K2 or the high-level threshold of the second input terminal of U1, controllable switch is opened, into
One step makes lower edge switch input terminal approximately ground, prevents heavy current impact caused by SCB failures from leading to the damage of TCU.
Further, by the setting to AND gate circuit, second control signal can be increased, to the switch after troubleshooting
Protection circuit is resetted.
The present invention by increase based on controllable switch K2 low side output rapidly switch off circuit after, in work
The processing of SCB fault diagnosises shorten to Microsecond grade by Millisecond, avoids the damage to controller, while can also meet ISO26262
The strict demand of functional safety.
The second end of one load 10 of the connection of output end 12 of the lower edge switch K1, the first end connection electricity of the load 10
Pond power supply Vbat, power supply Vbat are that load 10 provides power input, and constant pressure source VDD is 5V voltage sources.
After circuit being rapidly switched off by low side of the increase based on operational amplifier, when working for switching signal and PWM
The processing of SCB fault diagnosises shorten to Microsecond grade by former Millisecond, avoids the damage to master controller, while can also meet
The strict demand of ISO26262 functional safeties.
When SCB failures occur for the low side output of the PWM type driving circuits described in Fig. 4, it can trigger and rapidly switch off and protect
The state of failure latching is held, master controller can control the level state of signal S3 to monitor whether to occur SCB events by third
Barrier.After failure vanishes, master controller can export low level by S2 and be resetted, and be drawn at this time with the second input pins of door U1
It is low, realize fault unlock, you can shutdown controllable switch K2, low side driving continue to work normally.
To sum up, the various configuration of switch protecting circuit is described in detail in above-described embodiment, and certainly, the present invention includes
But it is not limited in above-mentioned implementation cited configuration, in any configuration provided in above-described embodiment on the basis of converted
Hold, belongs to the range that the present invention is protected.Those skilled in the art can draw inferences about other cases from one instance according to the content of above-described embodiment.
Foregoing description is only the description to present pre-ferred embodiments, not to any restriction of the scope of the invention, this hair
Any change, the modification that the those of ordinary skill in bright field does according to the disclosure above content, belong to the protection of claims
Range.
Claims (10)
1. a kind of switch protecting circuit, which is characterized in that the switch protecting circuit includes rapidly switching off circuit and controllable switch,
Wherein：
The circuit that rapidly switches off includes the first diode, the second diode, 3rd resistor and the 4th the second capacitance of resistance, institute
The anode for stating the first diode connects the anode of second diode and the first end of the 4th resistance, the 4th electricity
The second end of resistance connects the output end of a lower edge switch, and the cathode of first diode couples the input of the lower edge switch
End, the cathode of second diode connect the input terminal of the controllable switch, described in the output end connection of the controllable switch
The input terminal of lower edge switch；
Described 3rd resistor one end connects the cathode of second diode, other end ground connection；
Second capacitance is in parallel with the 3rd resistor.
2. switch protecting circuit as described in claim 1, which is characterized in that
Under normal circumstances, a first control signal is provided to the input terminal of the lower edge switch, and the first control signal is
When the first level, the output end of the lower edge switch is second electrical level, described low when the first control signal is second electrical level
The output end ground connection of side switch, wherein the first level is less than second electrical level.
3. switch protecting circuit as claimed in claim 2, which is characterized in that described controllable when the controllable switch disconnects
The output of switch is high-impedance state, and when the controllable switch is closed, the output end of the controllable switch is grounded；
When the first control signal is located at second electrical level for the second end of second electrical level and the 4th resistance, described second
Diode current flow, the controllable switch are closed；
When the first control signal is located at second electrical level for the second end of the first level and the 4th resistance, described second
Diode turns off, and the controllable switch disconnects；
When the first control signal is located at the first level for the second end of second electrical level and the 4th resistance, described second
Diode turns off, and the controllable switch disconnects.
4. switch protecting circuit as claimed in claim 3, which is characterized in that one load of switch protecting circuit connection, institute
The first end connection main power source of load is stated, the second end of the load connects the lower edge switch by the first capacity earth
Output end；
The switch protecting circuit further includes second resistance, and one end of the second resistance inputs the first control signal, separately
One end connects the input terminal of the lower edge switch.
5. switch protecting circuit as claimed in claim 4, which is characterized in that it is described rapidly switch off circuit further include and door electricity
Road, wherein：
One second control signal is provided to the first input end of the AND gate circuit；Second input terminal of the AND gate circuit connects
The cathode of second diode；The output end of the AND gate circuit couples the input terminal of the controllable switch.
6. switch protecting circuit as claimed in claim 5, which is characterized in that the first control signal is believed for pulsewidth modulation
Number.
7. switch protecting circuit as claimed in claim 5, which is characterized in that the load further includes the 6th diode, described
The anode of 6th diode connects the second end of the load, and the cathode of the 6th diode connects the main power source.
8. switch protecting circuit as claimed in claim 5, which is characterized in that the circuit that rapidly switches off further includes the 5th electricity
Resistance, the 6th resistance, third diode, the 4th diode and the 5th diode, wherein：
The both ends of 5th resistance are separately connected the input terminal of the output end and the controllable switch of the AND gate circuit；
The both ends of 6th resistance are separately connected the first input end of the output end and the AND gate circuit of the lower edge switch；
The anode of the third diode connects the output end of the AND gate circuit, described in the cathode connection of the third diode
Second input terminal of AND gate circuit；
The anode of 4th diode connects the first input end of the AND gate circuit, the cathode connection of the 4th diode
One constant pressure source；
The anode of 5th diode connects the first input end of the AND gate circuit, the cathode input of the 5th diode
The second control signal.
9. the switch protecting circuit as described in claim 3 or 5, which is characterized in that second capacitance, 3rd resistor, the 4th
The selection of resistance and the second diode should meet t and be more than the lower edge switch closing course time, wherein：
Wherein, R=R3*R4/ (R3+R4), Ut=Vth, U0=0V, Us=(Vbat-Vf) * R3/ (R3+R4), if (Vbat-
Vf) * R3/ (R3+R4) >=5V, then US=5V, wherein：Vth is the cut-in voltage of the controllable switch or the AND gate circuit
High-level threshold voltage, Vbat are main supply voltage value, and Vf is the conduction voltage drop of the second diode, and R3 is the resistance of 3rd resistor
Value, R4 are the resistance value of the 4th resistance, and C is the capacitance of the second capacitance.
10. switch protecting circuit as described in claim 1, which is characterized in that first diode and the two or two pole
The conducting voltage of pipe is equal.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202042892U (en) * | 2011-04-06 | 2011-11-16 | 浙江001集团有限公司 | Switch protecting circuit |
| CN202503267U (en) * | 2012-03-13 | 2012-10-24 | 中国矿业大学 | Intrinsic safety type output short circuit protection device of high power switch converter |
| CN103683258A (en) * | 2013-11-28 | 2014-03-26 | 成都市宏山科技有限公司 | Power interface protecting circuit applicable to mobile equipment |
| CN204087034U (en) * | 2014-08-07 | 2015-01-07 | 广州海格通信集团股份有限公司 | There is the Anti-surging power switch protection circuit of over-voltage protecting function |
| CN204089759U (en) * | 2014-09-12 | 2015-01-07 | 叶良地 | High-frequency power device switch protecting circuit |
-
2018
- 2018-01-30 CN CN201810091133.2A patent/CN108418189B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202042892U (en) * | 2011-04-06 | 2011-11-16 | 浙江001集团有限公司 | Switch protecting circuit |
| CN202503267U (en) * | 2012-03-13 | 2012-10-24 | 中国矿业大学 | Intrinsic safety type output short circuit protection device of high power switch converter |
| CN103683258A (en) * | 2013-11-28 | 2014-03-26 | 成都市宏山科技有限公司 | Power interface protecting circuit applicable to mobile equipment |
| CN204087034U (en) * | 2014-08-07 | 2015-01-07 | 广州海格通信集团股份有限公司 | There is the Anti-surging power switch protection circuit of over-voltage protecting function |
| CN204089759U (en) * | 2014-09-12 | 2015-01-07 | 叶良地 | High-frequency power device switch protecting circuit |
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