CN110445498A - Current potential holding circuit and current foldback circuit - Google Patents
Current potential holding circuit and current foldback circuit Download PDFInfo
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- CN110445498A CN110445498A CN201910703514.6A CN201910703514A CN110445498A CN 110445498 A CN110445498 A CN 110445498A CN 201910703514 A CN201910703514 A CN 201910703514A CN 110445498 A CN110445498 A CN 110445498A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/02—Transmitters
- H04B1/04—Circuits
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Abstract
This application involves a kind of current potential holding circuit, the current potential holding circuit includes: power supply unit, rest-set flip-flop, high level unit, low level cell, unit to be charged and comparing unit；First output pin of rest-set flip-flop is connect with the 5th input pin, and the second output pin is connect with the 6th input pin, and third output pin is connect with the second input pin；High level unit is connect with the first, second input pin；Low level cell is connect with third, the 4th input pin；Comparing unit is connect with power supply unit, and power supply unit is connect with the first input pin, the comparison result of real-time voltage and threshold voltage that comparing unit is inputted according to power supply unit, to the first input pin input low level or high level；Second output pin is connect with unit to be charged.Present invention also provides a kind of current foldback circuits, avoid overcurrent after overcurrent occurs for circuit using upper rheme holding circuit and disappear, low level output, which cannot keep, causes circuit can not work normally.
Description
Technical field
This application involves circuit fields, more particularly to a kind of current potential holding circuit and current foldback circuit.
Background technique
In transmitter design, transmitter is burnt because of overcurrent in order to prevent, and current foldback circuit generally can all be added.It is logical
Normal current foldback circuit is all that transmitter supply current is converted to corresponding voltage by current sensor, then by this
Comparator is accessed after voltage, the low and high level exported by comparator is to determine whether overcurrent.If overcurrent, comparator
Output level can change, thus transmitter power switch disconnect, protect transmitter.System is in not overcurrent shape after disconnection
State, switch will re-close again, and transmitter re-powers, and sequentially recycles, and can not work normally transmitter.
However, in the prior art, the output of comparator usually being accessed single-chip microcontroller, judges whether overcurrent by single-chip microcontroller
And current potential holding is carried out, the Infinite Cyclic being closed immediately after disconnecting to avoid switch can not work normally transmitter, but monolithic
The introducing of machine increases the complexity of whole design.
Summary of the invention
Based on this, it is necessary in view of the above technical problems, provide a kind of current potential holding circuit and current foldback circuit.
On the one hand, the present invention provides a kind of current potential holding circuits, comprising:
Power supply unit, rest-set flip-flop, high level unit, low level cell, unit to be charged and comparing unit；
The rest-set flip-flop includes the first NAND gate, the second NAND gate and third NAND gate, the first NAND gate packet
The first input pin, the second input pin and the first output pin are included, second NAND gate includes third input pin,
Four input pins and the second output pin, the third NAND gate include the 5th input pin, the 6th input pin and the
Three output pins；
First output pin is connect with the 5th input pin, and second output pin and the 6th input pin connect
It connects, the third output pin is connect with the second input pin；
The high level unit is connect with the first input pipe, the second input pin, for for first input pin and
Second input pin input high level；The low level cell is connect with third input pin, the 4th input pin, is used for as institute
State third input pin and the 4th input pin input low level；The comparing unit is connect with power supply unit, and the power supply is single
Member is connect with the first input pin, and said supply unit is used to power to the current potential holding circuit, and the comparing unit is used for
According to the comparison result of the real-time voltage of said supply unit input and threshold voltage, the first input pin of Xiang Suoshu inputs low electricity
Flat or high level；Second output pin is connect with unit to be charged, for charging for the unit to be charged.
The high level unit includes power supply and pull-up resistor in one of the embodiments, and the power supply passes through pull-up
Resistance is connect with first input pin and the second input pin.
The low level cell includes ground unit in one of the embodiments,.
The unit to be charged is charging capacitor in one of the embodiments,.
The comparing unit includes current sensor and comparator in one of the embodiments,；
The current sensor is used to the real-time input current of said supply unit being converted to real-time input voltage；
The comparator is used for the threshold voltage of the real-time input voltage and the comparator, and ties according to comparing
Fruit is to the first input pin input low level or high level；
Wherein, when the real-time input voltage is less than or equal to the threshold voltage, the comparing unit is to described first
Input pin input high level；When the real-time input voltage is greater than the threshold voltage, the comparing unit is to described the
One input pin input low level.
On the other hand, the present invention also provides a kind of current foldback circuits, comprising: current potential holding circuit, switch unit with
And working cell；
The current potential holding circuit includes power supply unit, rest-set flip-flop, high level unit, low level cell, list to be charged
Member and comparing unit；
The rest-set flip-flop includes the first NAND gate, the second NAND gate and third NAND gate, the first NAND gate packet
The first input pin, the second input pin and the first output pin are included, second NAND gate includes third input pin,
Four input pins and the second output pin, the third NAND gate include the 5th input pin, the 6th input pin and the
Three output pins；
First output pin is connect with the 5th input pin, and second output pin and the 6th input pin connect
It connects, the third output pin is connect with the second input pin, switch unit；
The high level unit is connect with the first input pipe, the second input pin, for for first input pin and
Second input pin input high level；The low level cell is connect with third input pin, the 4th input pin, is used for as institute
State third input pin and the 4th input pin input low level；The comparing unit is connect with power supply unit, and the power supply is single
Member is connect with the first input pin, and said supply unit is used to power to the current potential holding circuit, and the comparing unit is used for
According to the comparison result of the real-time voltage of said supply unit input and threshold voltage, the first input pin of Xiang Suoshu inputs low electricity
Flat or high level；Second output pin is connect with unit to be charged, for charging for the unit to be charged；The third
Output pin is connect with the switch unit, and the switch unit is connect with working cell, and the switch unit is used for according to institute
Working cell described in the low level control of third output pin output is stated to stop working.
The high level unit includes power supply and pull-up resistor in one of the embodiments, and the power supply passes through pull-up
Resistance is connect with the first input pin of institute and the second input pin.
The low level cell includes ground unit in one of the embodiments,.
The unit to be charged is charging capacitor in one of the embodiments,.
The comparing unit includes current sensor and comparator in one of the embodiments,；
The current sensor is used to the real-time input current of said supply unit being converted to real-time input voltage；
The comparator is used for the threshold voltage of the real-time input voltage and the comparator, and ties according to comparing
Fruit is to the first input pin input low level or high level；
Wherein, when the real-time input voltage is less than or equal to the threshold voltage, the comparing unit is to described first
Input pin input high level；When the real-time input voltage is greater than the threshold voltage, the comparing unit is to described the
One input pin input low level.
In the embodiment of the present invention, the current potential holding circuit includes power supply unit, rest-set flip-flop, high level unit, low electricity
Flat unit, unit to be charged and comparing unit；The first output pin in the rest-set flip-flop is connect with the 5th input pin,
Second output pin is connect with the 6th input pin, and third output pin is connect with the second input pin；High level unit and
One input pin, the connection of the second input pin；Low level cell is connect with third input pin, the 4th input pin；Compare list
Member is connect with power supply unit, and power supply unit is connect with the first input pin；Second output pin is connect with unit to be charged.Pass through
The specific connection structure of above-mentioned current potential holding circuit, it is defeated by first by high level unit in unit not enough power supply to be charged
The incoming level for entering pin and the second input pin is drawn high, so that the first output pin exports low level to the 5th input pin；
The incoming level of third input pin and the 4th input pin is dragged down by low level cell, so that the second output pin exports
High level is unit to be charged charging, and the 6th input pin input low level, third output pin exports high level, until wait fill
Electric unit electricity is full of；After unit electricity to be charged is full of, the 6th input pin receives the height electricity of the second output pin output
It is flat, by power supply unit for current potential holding circuit power supply, the real-time voltage inputted by comparing unit according to power supply unit
With the comparison result of threshold voltage, to the first input pin input low level or high level.Realization first inputs low in comparing unit
Level, in the case that third output pin exports low level, then input high level, third output pin keeps output low level,
With this realize the current potential holding circuit incoming level be mutated again restore in the case where keep low level output, avoid electricity
Flat output cannot keep the problem of can not work normally circuit.
Detailed description of the invention
Fig. 1 is the schematic diagram of current potential holding circuit in one embodiment provided by the invention；
Fig. 2 is the schematic diagram of current potential holding circuit in another embodiment provided by the invention；
Fig. 3 is the schematic diagram of current foldback circuit in one embodiment provided by the invention；
Fig. 4 is the flow diagram that current potential keeps control method in one embodiment provided by the invention；
Fig. 5 is the flow diagram of overcurrent protection control method in one embodiment provided by the invention.
Specific embodiment
It is with reference to the accompanying drawings and embodiments, right in order to which the objects, technical solutions and advantages of the application are more clearly understood
The application is further elaborated.It should be appreciated that specific embodiment described herein is only used to explain the application, not
For limiting the application.
It referring to Fig.1, is the schematic diagram of current potential holding circuit in one embodiment provided by the invention.The current potential keeps electricity
Road 100 include: power supply unit 110, rest-set flip-flop 120, high level unit 130, low level cell 140, unit to be charged 150 with
And comparing unit 160.
Specifically, as shown in Figure 1, the rest-set flip-flop 120 includes the first NAND gate 121, the second NAND gate 122 and the
Three NAND gates 123, first NAND gate 121 are defeated including the first input pin 1201, the second input pin 1202 and first
Pin 1211 out, second NAND gate 122 include third input pin 1203, the 4th input pin 1204 and the second output
Pin 1221, the third NAND gate 123 include the 5th input pin 1205, the 6th input pin 1206 and third efferent duct
Foot 1231.
Specifically, first output pin 1211 is connect with the 5th input pin 1205, second output pin
1221 connect with the 6th input pin 1206, and the third output pin 1231 is connect with the second input pin 1202.The height
Level-cell 130 is connect with the first input pin 1201, the second input pin 1202, and the low level cell 140 and third are defeated
Enter pin 1203, the connection of the 4th input pin 1204, the unit 150 to be charged is connect with the second output pin 1221, described
Power supply unit 110 is connect with comparing unit 160, and the comparing unit 160 is connect with the first input pin 1201.
Wherein, said supply unit 110 is used to power to the current potential holding circuit 100.It is in said supply unit 110
Before the current potential holding circuit 100 is powered, when 150 not enough power supply of unit to be charged, the high level unit 130 is for drawing
The incoming level of high first input pin 1201 and second input pin 1202, so that first input pin
1201 and 1202 input high level of the second input pin, first output pin 1211 exports low level to the 5th input
Pin 1205.The low level cell 140 is used to drag down the defeated of the third input pin 1203 and the 4th input pin 1204
Enter level, so that the third input pin 1203 and 1204 input low level of the 4th input pin, second output pin
1221 output high level are that the unit 150 to be charged charges, 1206 input low level of the 6th input pin, until described
150 electricity of unit to be charged is full of.Said supply unit 110 passes through described after 150 electricity of unit to be charged is full of
One input pin 1201 is the current potential holding circuit 100 power supply.The comparing unit 160 is used for according to said supply unit
The real-time voltage of 110 inputs and the comparison result of threshold voltage, 1201 input low level of the first input pin of Xiang Suoshu or high electricity
It is flat.
The potential property table of 1 rest-set flip-flop of table
Table 1 is please referred to, is the potential property table of rest-set flip-flop in current potential holding circuit of the present invention.
Wherein, referring to Fig.1, S point is the current potential leading point of the 6th input pin 1206, and R point is first input
The current potential leading point of pin 1201, Q point are that the current potential of the second input pin 1202 described in the third output pin 1231/ is drawn
Point, 1 indicates that high level, O indicate low level.
In 150 not enough power supply of unit to be charged, the S point is in low level (0), the high level unit 130
So that R point and QnPoint is in high level (1), and the third output pin 1231 exports high level (1), i.e. Qn+1In high level
(1).Said supply unit 110 is the circuit state of the current potential holding circuit 100 before the current potential holding circuit 100 power supply
Set 1.
When 150 electricity of unit to be charged is full of, the 6th input pin 1206 inputs second output pin
The high level of 1221 outputs, S point are in high level (1).Said supply unit 110 is the current potential holding circuit 100 power supply, institute
State the comparison result of real-time voltage and threshold voltage that comparing unit 160 is inputted according to said supply unit 110, Xiang Suoshu current potential
100 input low level of holding circuit or high level.
When said supply unit 110 input real-time voltage be first greater than the threshold voltage when, the comparing unit 160 to
100 input low level of current potential holding circuit, 1201 input low level of the first input pin, R point are in low level
(0)；Second input pin 1202 receives the high level that the third output pin 1231 exports, QnIt is defeated in the third
High level (1) state that pin 1231 exports out；First output pin 1211 exports high level, the 5th input pin
1205 input high levels, the third output pin 1231 export low level, i.e. Qn+1In low level (0), the current potential is kept
The circuit state of circuit 100 sets 0.And then, when the real-time voltage that said supply unit 110 inputs is less than or equal to the threshold value again
When voltage, the comparing unit 160 is in high level (1) to 100 input high level of current potential holding circuit, R point；Described
Two input pins 1202 receive the low level that the third output pin 1231 exports, QnIn the third output pin 1231
Low level (0) state of output；First output pin 1211 exports high level, and the 5th input pin 1205 inputs height
Level, the third output pin 1231 export low level, i.e. Qn+1In low potential (0), the current potential holding circuit 100
Circuit state keeps 0.It is realized when to 100 input low level of current potential holding circuit with this, the third output pin
1231 output low levels, then when to 100 input high level of current potential holding circuit, the current potential holding circuit 100 is still kept
Export low level, ensure that the holding of low level output, avoid level output cannot keep caused by circuit can not normal work
The problem of making.
Referring to Fig. 2, being the schematic diagram of current potential holding circuit in another embodiment provided by the invention.
In the present embodiment, the high level unit 230 includes power Vcc and pull-up resistor R1 and R2, and the power Vcc is logical
It crosses the pull-up resistor R1 to connect with the first input pin 2201, passes through the pull-up resistor R2 and the second input pin 2202
Connection, in 250 not enough power supply of unit to be charged, by first input pin 2201 and the second input pin 2202
Incoming level is drawn high, input high level (R point and Q point are in high level), and first output pin 2211 exports low level.
In another embodiment, the low level cell 240 includes ground unit, so that the third input pin 2203
With 2204 input low level of the 4th input pin, second output pin 2221 exports high level.
In the present embodiment, the third input pin 2203 and the 4th input pin 2204 are directly grounded, described in realizing
The effect of ground unit, the third input pin 2203 and 2204 input low level of the 4th input pin, second output
Pin 2221 exports high level, charges for the unit 250 to be charged, until 250 electricity of unit to be charged is full of.
In another embodiment, the unit to be charged 250 is charging capacitor C1, the charging capacitor C1 ground connection.Institute
It states before charging capacitor C1 electricity is full of, 2206 input low level of the 6th input pin (S point is in low level), the charging
After capacitor C1 electricity is full of, the 6th input pin 2206 receives high level (the S point that second output pin 2221 exports
In high level).It is realized with this in the charging capacitor C1 not enough power supply, the S point is in low level (0), the high electricity
Flat unit 230 makes R point and QnPoint is in high level (1), and the third output pin 2231 exports high level (1), i.e. Qn+1Place
In high level (1), before said supply unit 210 is the current potential holding circuit 200 power supply, the current potential holding circuit 200
Circuit state sets 1.
After the charging capacitor C1 electricity is full of, 2206 input high level of the 6th input pin, S point is in high level
(1), said supply unit 210 is the current potential holding circuit 200 power supply, and the comparing unit 260 is according to said supply unit
The real-time voltage of 210 inputs and the comparison result of threshold voltage, 200 input low level of Xiang Suoshu current potential holding circuit or high electricity
It is flat.
In another embodiment, the comparing unit 260 includes current sensor 261 and comparator 262.
Specifically, the current sensor 261 is for being converted in real time the real-time input current of said supply unit 210
Input voltage.The comparator 262 is used for the threshold voltage of the real-time input voltage and the comparator 262, and root
According to comparison result to 2201 input low level of the first input pin or high level.
Specifically, the comparing unit 260 is to described when the real-time input voltage is less than or equal to the threshold voltage
First input pin, 2201 input high level；When the real-time input voltage is greater than the threshold voltage, the comparing unit
260 to 2201 input low level of the first input pin.
In another embodiment, the rest-set flip-flop 220 further includes power pins 2209, is connect with the power Vcc, institute
Power Vcc is stated as the rest-set flip-flop 220 power supply.
In another embodiment, the rest-set flip-flop 220 further includes electric capacity of voltage regulation C2, in parallel with the power Vcc, described
Electric capacity of voltage regulation C2 ground connection, to filter out the ripple of the power Vcc output voltage, during charge and discharge, makes output voltage base
This stabilization.
Specifically, the rest-set flip-flop 220 further includes grounding pin 2210, the grounding pin 2210 is grounded.
In the present embodiment, the rest-set flip-flop 220 uses monolithic 74HC00.As shown in Fig. 2, the monolithic 74HC00 includes
Four NAND gates, when carrying out current potential holding control using monolithic 74HC00, the 7th input pin 2207 of the 4th NAND gate 224,
8th input pin 2208 and the 4th output pin 2241 are vacant.
Current potential holding circuit in the present embodiment is connected by simple NAND gate circuit, is described in said supply unit
Before the charging of current potential holding circuit, the first input pin and the second input pin input high level are made by power supply and pull-up resistor,
It being grounded by third input pin and the 4th input pin, the second output pin exports high level and charges for charging capacitor, and the 6th
Input pin input low level, until the charging capacitor electricity is full of, the 6th input pin input high level, the confession
Electric unit is powered to the current potential holding circuit, the real-time voltage and threshold value that the comparing unit is inputted according to said supply unit
The comparison result of voltage realizes the comparing unit to described to the first input pin input low level or high level, with this
First input pin input low level, the third output pin export low level, and the comparing unit is defeated to described first again
Enter pin input high level, the third output pin keeps output low level, and avoiding low level output and cannot keep causes
The problem of circuit can not work normally, while the present embodiment can be directly based upon existing element monolithic 74HC00, selective circuit connects
It connects, realizes the purpose that low potential is kept, further save circuit cost.
Referring to Fig. 3, being the schematic diagram of current foldback circuit in one embodiment provided by the invention.The overcurrent protection
Circuit 300 includes: current potential holding circuit 200, switch unit 310 and working cell 320.
In the present embodiment, the current potential holding circuit 200 such as above-mentioned current potential holding circuit (Fig. 2) provided by the invention, In
This is repeated no more.
Specifically, the switch unit 310 is connect with the third output pin 2231 of the current potential holding circuit 200, institute
It states switch unit 310 to connect with working cell 320, described in the level control for being exported according to the third output pin 2231
The work or stopping of working cell 320.
When the third output pin 2231 exports high level, the switch unit 310 is closed, the working cell 320
Work；When the third output pin 2231 exports low level, the switch unit 310 is disconnected, and the working cell 320 stops
Work.
In the present embodiment, the working cell 320 is transmitter, and in other embodiments, the working cell 320 can be it
His circuit element, is not specifically limited herein.
The present embodiment is obtaining the power supply by the comparator in the current foldback circuit for including the transmitter
(overcurrent occurs) when the real-time voltage of unit input is greater than the threshold voltage, the first input pin input low level, institute
Third output pin output low level is stated, the switch unit disconnects, and the transmitter stops working；When passing through the comparison again
The real-time voltage that device obtains said supply unit input is less than or equal to when the threshold voltage (overcurrent disappearance), first input
Pin input high level, the third output pin export low level, and the switch unit is continuously turned off state, the transmitter
Stop working state is kept, to realize in the case where overcurrent disappears after overcurrent occurs for the current foldback circuit, described the
Three output pins keep low level output, avoid in the prior art occur overcurrent after overcurrent disappear caused by low level output
It cannot keep, disconnected Infinite Cyclic can not work normally transmitter when switch unit opens.
Referring to Fig. 4, be the flow diagram that current potential keeps control method in one embodiment provided by the invention, in conjunction with
Table 1 and Fig. 1, the current potential holding control method include:
Step S41: being first input pipe by the high level unit when the unit not enough power supply to be charged
Foot and the second input pin input high level.
Specifically, in conjunction with Fig. 2, in the present embodiment, the high level unit 230 include power Vcc and pull-up resistor R1 and
R2, the power Vcc are connect by pull-up resistor R1 with the first input pin 2201, defeated by pull-up resistor R2 and institute first
Enter the connection of pin 2201.
Before said supply unit 210 is the current potential holding circuit 200 power supply, when 250 electricity of unit to be charged
When insufficient, the high level of the power Vcc is inputted into first input pin 2201 and the second input pin 2202, the electricity
Source Vcc can make first input pin 2201 and the second input pin 2202 be in high level in powered on moment.To avoid breaking
Short circuit accesses pull-up resistor R1 between the power Vcc and first input pin 2201 and the second input pin 2202
And R2, by the power Vcc and pull-up resistor R1 and R2 by first input pin 2201 and the second input pin 2202
Incoming level draw high so that 2202 input high level of first input pin 2201 and the second input pin, described first
Output pin 2211 exports low level to the 5th input pin 2205.
Step S42: by the low level cell be the third input pin and the 4th input pin input low level,
It charges for the unit to be charged, until the unit electricity to be charged is full of.
Specifically, the third input pin 2203 and the 4th input pin 2204 are grounded by the ground unit,
It is defeated by second output pin 2221 for the third input pin 2203 and 2204 input low level of the 4th input pin
High level charges to the unit 250 to be charged out, until 150 electricity of unit to be charged is full of.In the list to be charged
Before first 250 electricity are full of, the high level that second output pin 2221 exports is used to charge for the unit 250 to be charged,
Do not reach the 6th input pin 2206 also, therefore, before 250 electricity of unit to be charged is full of, the 6th input
2206 input low level of pin, the third output pin 2231 export high level.
In conjunction with Fig. 2, in the present embodiment, the third input pin 2203 and the 4th input pin 2204 are directly grounded with reality
The effect of the existing low level cell 240.
In conjunction with Fig. 2, in the present embodiment, the unit 250 to be charged is charging capacitor C1.
Step S43: being current potential holding circuit confession by said supply unit after the unit electricity to be charged is full of
Electricity.
Specifically, the charging capacitor C1 discharges after the charging capacitor C1 electricity is full of, described second is exported
For the high level output that pin 2221 exports to the 6th input pin 2206, the 6th input pin 2206 receives described the
The high level of two output pins 2221 output, said supply unit 210 are the current potential by first input pin 2201
Holding circuit 200 is powered.
Step S44: pass through the ratio of real-time voltage and threshold voltage that the comparing unit is inputted according to said supply unit
Compared with as a result, to the first input pin input low level or high level.
Specifically, in the present embodiment, the comparing unit 260 includes current sensor 261 and comparator in conjunction with Fig. 2
262.It is the current potential holding circuit 200 power supply by said supply unit 210 after the charging capacitor C1 electricity is full of,
The real-time input current of said supply unit 210 is converted into real-time input voltage by the current sensor 261；Pass through institute
State the threshold voltage of the comparator 262 real-time input voltage and the comparator 262, and according to comparison result to described
First input pin, 2201 input low level or high level.
Specifically, the comparing unit 260 is to described when the real-time input voltage is less than or equal to the threshold voltage
First input pin, 2201 input high level；When the real-time input voltage is greater than the threshold voltage, the comparing unit
260 to 2201 input low level of the first input pin.
Specifically, becoming larger suddenly in said supply unit 210 to the electric current that the current potential holding circuit 200 inputs, pass through
The real-time input current of said supply unit 210 is converted to real-time input voltage by the current sensor 261, passes through the ratio
When obtaining threshold voltage of the real-time input voltage greater than the comparator 262 compared with device 262, the current potential holding circuit 200
Overcurrent occurs.Overcurrent moment, for the comparing unit 260 to 2201 input low level of the first input pin, described second is defeated
Enter pin 2202 and receives the high level exported by the third output pin 2231 before the input current becomes larger suddenly.This
When, first output pin 2211 exports high level to the 5th input pin 2205, the 6th input pin 2206
The high level that second output pin 2221 exports is received, the third output pin 2231 exports low level.Again when passing through
The real-time input current of said supply unit 210 is converted to real-time input voltage by the current sensor 261, passes through the ratio
When obtaining threshold voltage of the real-time input voltage less than or equal to the comparator 262 compared with device 262, the current potential holding circuit
200 restore normal.Overcurrent disappears, and the comparing unit 260 is to 2201 input high level of the first input pin, and described second
Input pin 2202 receives the low level exported by the third output pin 2231 before the input current restores.At this point,
First output pin 2211 exports high level to the 5th input pin 2205, and the 6th input pin 2206 receives
The high level that second output pin 2221 exports, the third output pin 2231 keep output low level.
In the present embodiment, before said supply unit is current potential holding circuit power supply, the charging capacitor electricity is not
When sufficient, the first input pin and the second input pin input high level are made by power supply and pull-up resistor, the first output pin is defeated
Low level is grounded input low level, the second output by third input pin and the 4th input pin to the 5th output pin out
Pin exports high level as charging capacitor charging, and the 6th input pin input low level, third output pin exports high level, directly
It is full of to the charging capacitor electricity.After charging capacitor electricity is full of, said supply unit is supplied to the current potential holding circuit
Electricity, the comparison result of real-time voltage and threshold voltage that the comparing unit is inputted according to said supply unit are defeated to described first
Enter pin input low level or high level, realizes that the third output pin exports low level after overcurrent occurs, overcurrent disappears
The third output pin still keeps output low level afterwards, realizes the purpose that low potential is kept, and avoiding level output can not protect
Hold the problem of causing circuit can not work normally.
Referring to Fig. 5, be the flow diagram of overcurrent protection control method in one embodiment provided by the invention, it is described
Over-current protection method is applied to current foldback circuit, for example above-mentioned current foldback circuit provided by the invention of the current foldback circuit
300 (Fig. 3), details are not described herein for specific connection structure, compares, this implementation with the current potential holding circuit control method (Fig. 4)
Overcurrent protection control method described in example further include:
Step S54: switch unit working cell according to the low level control that the third output pin exports
It stops working.
Specifically, the switch unit 310 controls the work according to the level that the third output pin 2231 exports
Unit 320 works or stops working.
Specifically, the switch unit 310 disconnects, the work when the third output pin 2231 exports low level
Make unit 320 to stop working；When the third output pin 2231 exports high level, the switch unit 310 is closed, described
Working cell 320 works.
In the present embodiment, the working cell 320 is transmitter.In the overcurrent protection scene being applied in transmitter,
The real-time input current of said supply unit 210 is converted into real-time input voltage by the current sensor 261；Pass through institute
The threshold voltage for stating the comparator 262 real-time input voltage and the comparator 262, when the real-time input voltage is big
When the threshold voltage, overcurrent occurs for the current foldback circuit 300.Overcurrent moment, the comparing unit 260 is to described
One input pin, 2201 input low level, second input pin 2202 receive before overcurrent occurs by the third efferent duct
The high level that foot 2231 exports.At this point, first output pin 2211 exports high level to the 5th input pin 2205,
6th input pin 2206 receives the high level that second output pin 2221 exports, the third output pin 2231
Low level is exported, the switch unit 310 disconnects, and the transmitter stops working.It is incited somebody to action again when by the current sensor 261
The real-time input current of said supply unit 210 is converted to real-time input voltage, is obtained by the comparator 262 described real-time
When input voltage is less than or equal to the threshold voltage of the comparator 262,300 electric current of current foldback circuit restores normal.It crosses
Stream disappears, and the comparing unit 260 exists to 2201 input high level of the first input pin, second input pin 2202
The input current receives the low level exported by the third output pin 2231 before restoring.At this point, first efferent duct
Foot 2211 exports high level to the 5th input pin 2205, and the 6th input pin 2206 receives second efferent duct
The high level that foot 2221 exports, the third output pin 2231 keep output low level, and the switch unit 310 remains open
State, so that the transmitter is continuously in the state to stop working.It is realized with this and exports low level control after overcurrent occurs
Transmitter stops working, and overcurrent still keeps output low level control transmitter still in the state to stop working after disappearing, and realizes
The purpose of overcurrent protection, avoid in the prior art occur overcurrent after overcurrent disappear caused by output level cannot keep, open
The problem of disconnected Infinite Cyclic can not work normally transmitter when opening when closing unit.
In conclusion passing through the comparator overcurrent protection electricity in overcurrent protection control method provided by the invention
The threshold voltage of the real-time input current on road converted next real-time input voltage and the comparator, using current potential holding circuit
Switch unit is controlled, overcurrent disappears again after overcurrent occurs for the current foldback circuit, is existed using current potential holding circuit
Overcurrent still keeps low level output in the case where disappearing again after generation overcurrent, and control switch unit is constantly in off-state, keeps away
Exempt from that overcurrent occurs due to circuit, switch unit cannot keep after disconnecting, and the Infinite Cyclic being closed immediately again after overcurrent disappearance makes
Transmitter cisco unity malfunction.
Each technical characteristic of above embodiments can be combined arbitrarily, for simplicity of description, not to above-described embodiment
In each technical characteristic it is all possible combination be all described, as long as however, the combination of these technical characteristics be not present lance
Shield all should be considered as described in this specification.
The several embodiments of the application above described embodiment only expresses, the description thereof is more specific and detailed, but simultaneously
It cannot therefore be construed as limiting the scope of the patent.It should be pointed out that coming for those of ordinary skill in the art
It says, without departing from the concept of this application, various modifications and improvements can be made, these belong to the protection of the application
Range.Therefore, the scope of protection shall be subject to the appended claims for the application patent.
Claims (10)
1. a kind of current potential holding circuit characterized by comprising
Power supply unit, rest-set flip-flop, high level unit, low level cell, unit to be charged and comparing unit；
The rest-set flip-flop includes the first NAND gate, the second NAND gate and third NAND gate, and first NAND gate includes the
One input pin, the second input pin and the first output pin, second NAND gate includes third input pin, the 4th defeated
Enter pin and the second output pin, the third NAND gate includes that the 5th input pin, the 6th input pin and third are defeated
Pin out；
First output pin is connect with the 5th input pin, and second output pin is connect with the 6th input pin, institute
Third output pin is stated to connect with the second input pin；
The high level unit is connect with the first input pipe, the second input pin, for being first input pin and second
Input pin input high level；The low level cell is connect with third input pin, the 4th input pin, for being described the
Three input pins and the 4th input pin input low level；The comparing unit is connect with power supply unit, said supply unit with
The connection of first input pin, said supply unit are used to power to the current potential holding circuit, and the comparing unit is used for basis
Said supply unit input real-time voltage and threshold voltage comparison result, Xiang Suoshu the first input pin input low level or
High level；Second output pin is connect with unit to be charged, for charging for the unit to be charged.
2. current potential holding circuit according to claim 1, which is characterized in that the high level unit includes power supply and pull-up
Resistance, the power supply are connect by pull-up resistor with first input pin and the second input pin.
3. current potential holding circuit according to claim 1, which is characterized in that the low level cell includes ground unit.
4. current potential holding circuit according to claim 1, which is characterized in that the unit to be charged is charging capacitor.
5. current potential holding circuit according to claim 1, which is characterized in that
The comparing unit includes current sensor and comparator；
The current sensor is used to the real-time input current of said supply unit being converted to real-time input voltage；
The comparator be used for the real-time input voltage and the comparator threshold voltage, and according to comparison result to
The first input pin input high level or low level；
Wherein, when the real-time input voltage is less than or equal to the threshold voltage, the comparing unit is inputted to described first
Pin input high level；When the real-time input voltage is greater than the threshold voltage, the comparing unit is defeated to described first
Enter pin input low level.
6. a kind of current foldback circuit characterized by comprising
Current potential holding circuit, switch unit and working cell；
The current potential holding circuit include power supply unit, rest-set flip-flop, high level unit, low level cell, unit to be charged with
And comparing unit；
The rest-set flip-flop includes the first NAND gate, the second NAND gate and third NAND gate, and first NAND gate includes the
One input pin, the second input pin and the first output pin, second NAND gate includes third input pin, the 4th defeated
Enter pin and the second output pin, the third NAND gate includes that the 5th input pin, the 6th input pin and third are defeated
Pin out；
First output pin is connect with the 5th input pin, and second output pin is connect with the 6th input pin, institute
Third output pin is stated to connect with the second input pin, switch unit；
The high level unit is connect with the first input pipe, the second input pin, for being first input pin and second
Input pin input high level；The low level cell is connect with third input pin, the 4th input pin, for being described the
Three input pins and the 4th input pin input low level；The comparing unit is connect with power supply unit, said supply unit with
The connection of first input pin, said supply unit are used to power to the current potential holding circuit, and the comparing unit is used for basis
Said supply unit input real-time voltage and threshold voltage comparison result, Xiang Suoshu the first input pin input low level or
High level；Second output pin is connect with unit to be charged, for charging for the unit to be charged；The third output
Pin is connect with the switch unit, and the switch unit is connect with working cell, and the switch unit is used for according to described the
Working cell described in the low level control of three output pins output stops working.
7. current foldback circuit according to claim 6, which is characterized in that the high level unit includes power supply and pull-up
Resistance, the power supply are connect by pull-up resistor with the first input pin and the second input pin.
8. current foldback circuit according to claim 6, which is characterized in that the low level cell includes ground unit.
9. current foldback circuit according to claim 6, which is characterized in that the unit to be charged is charging capacitor.
10. current foldback circuit according to claim 6, which is characterized in that
The comparing unit includes current sensor and comparator；
The current sensor is used to the real-time input current of said supply unit being converted to real-time input voltage；
The comparator be used for the real-time input voltage and the comparator threshold voltage, and according to comparison result to
The first input pin input low level or high level；
Wherein, when the real-time input voltage is less than or equal to the threshold voltage, the comparing unit is inputted to described first
Pin input high level；When the real-time input voltage is greater than the threshold voltage, the comparing unit is defeated to described first
Enter pin input low level.
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| CN201910703514.6A CN110445498B (en) | 2019-07-31 | 2019-07-31 | Potential holding circuit and overcurrent protection circuit |
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| CN201910703514.6A CN110445498B (en) | 2019-07-31 | 2019-07-31 | Potential holding circuit and overcurrent protection circuit |
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