CN105226604B - A kind of under-voltage/over-voltage protection circuit and set top box - Google Patents
A kind of under-voltage/over-voltage protection circuit and set top box Download PDFInfo
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- CN105226604B CN105226604B CN201510644440.5A CN201510644440A CN105226604B CN 105226604 B CN105226604 B CN 105226604B CN 201510644440 A CN201510644440 A CN 201510644440A CN 105226604 B CN105226604 B CN 105226604B
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Abstract
The invention discloses a kind of under-voltage/over-voltage protection circuit, including：First voltage regulation unit, first resistor, second resistance, first amplification switching tube, second voltage regulation unit, 3rd resistor, 4th resistance, 5th resistance, second amplification switching tube, 6th resistance, 7th resistance and controlling switch pipe, the circuit, when input voltage is less than the second brownout threshold or more than overvoltage threshold, the controlling switch pipe of under-voltage/over-voltage protection circuit is all in cut-off state, disconnect the connection with power supply, only when input voltage is more than the second brownout threshold and is less than overvoltage threshold, controlling switch pipe is in the conduction state, enable power supply normally supply circuit, so as to realize the under-voltage/over-voltage protection to circuit, prevent the electronic component in circuit due to owe overvoltage cause to damage.Present invention also offers a kind of set top box, the set top box includes the under-voltage/over-voltage protection circuit, has under-voltage/over-voltage protection and prompting function, makes user that the working condition of set top box supply voltage be well understood.
Description
Technical field
The present invention relates to electronic technology field, more particularly to a kind of under-voltage/over-voltage protection circuit and set top box.
Background technology
At present, many families have multiple set top boxes simultaneously, and the supply voltage that different types of set top box needs is different, such as
The supply voltage of traditional set top box is 12V, and the supply voltage of network OTT set-top box is 5V, because 12V adapters and 5V are adapted to
Device seems closely similar, and user can power because misapplying 12V adapter to network OTT set-top box, and damage set top box；Or by mistake
With 5V adapter, and lead to not start shooting, or even damage adapter.
The content of the invention
Technical problem to be solved of the embodiment of the present invention is, there is provided a kind of under-voltage/over-voltage protection circuit and set top box,
The under-voltage/over-voltage protection circuit can realize the under-voltage/over-voltage protection of input voltage, prevent the damage caused by due to owing overvoltage of electronic component
It is bad.
The invention provides a kind of under-voltage/over-voltage protection circuit, including：First voltage regulation unit, first resistor, second resistance,
One amplification switching tube, the second voltage regulation unit, 3rd resistor, the 4th resistance, the 5th resistance, second amplification switching tube, the 6th resistance,
7th resistance and controlling switch pipe, wherein,
The input of the under-voltage/over-voltage protection circuit is used for the negative electrode for connecting first voltage regulation unit, first voltage stabilizing
The anode of unit connects one end of the first resistor, and the other end ground connection of the first resistor, described second resistance one end connects
Connect the anode of first voltage regulation unit and the common port of the first resistor, the second resistance other end connection described first
Amplify the control terminal of switching tube, the input end grounding of the first amplification switching tube, the negative electrode connection of second voltage regulation unit
The input of the circuit, the anode of second voltage regulation unit connect one end of the 3rd resistor, the 3rd resistor
The output end of other end connection the first amplification switching tube, one end of the 4th resistance connect the 3rd resistor with it is described
The common port of the output end of first amplification switching tube, the other end ground connection of the 4th resistance, one end of the 5th resistance connects
Connect the common port of the 3rd resistor and the 4th resistance, other end connection the second amplification switch of the 5th resistance
The control terminal of pipe, the input end grounding of the second amplification switching tube, one end of the 6th resistance connects the defeated of the circuit
Enter to hold, one end of other end connection the 7th resistance of the 6th resistance, described in the other end connection of the 7th resistance
The output end of second amplification switching tube, the input of the circuit connect the control terminal of the controlling switch pipe, and the control is opened
The output end for closing pipe connects the common port of the 6th resistance and the 7th resistance, the input connection of the controlling switch pipe
Power supply；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than the first brownout threshold, first voltage regulation unit
All do not puncture with second voltage regulation unit, described first amplifies the defeated of the control terminal of switching tube and the second amplification switching tube
It is zero to enter voltage, the first amplification switching tube and the second amplification switching tube cut-off, the control of the controlling switch pipe
The voltage of input and the voltage of the control terminal of the controlling switch pipe are high level, the controlling switch pipe cut-off；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than first brownout threshold and under-voltage less than second
Threshold value, then first voltage regulation unit do not puncture, the input voltage of control terminal of the first amplification switching tube is zero, described the
One amplification switching tube cut-off, the second voltage regulation unit breakdown, the input terminal voltage are less than in the partial pressure of the 4th resistance
The cut-in voltage that the control terminal of the second amplification switching tube needs, then the second amplification switching tube cut-off, the control are opened
The voltage for closing the voltage of the control signal of pipe and the control terminal of the controlling switch pipe is high level, the controlling switch pipe
Cut-off；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than second brownout threshold and is less than overvoltage threshold,
Then first voltage regulation unit does not puncture, and the input voltage of the control terminal of the first amplification switching tube is zero, and described first puts
Big switching tube cut-off, the second voltage regulation unit breakdown, the input terminal voltage are more than described in the partial pressure of the 4th resistance
The cut-in voltage that the control terminal of second amplification switching tube needs, the second amplification switching tube conducting, the controlling switch pipe
The voltage of input is more than the voltage of the control terminal of the controlling switch pipe, then the controlling switch pipe conducting；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than the overvoltage threshold, first voltage regulation unit
Breakdown, the first amplification switching tube conducting, the input voltage of the control terminal of the second amplification switching tube is zero, described second
Amplify switching tube cut-off, the voltage of the control signal of the controlling switch pipe and the voltage of the control terminal of the controlling switch pipe
It is high level, the controlling switch pipe cut-off；Wherein,
First brownout threshold is the second voltage regulation unit breakdown voltage；Second brownout threshold is described second
Voltage regulation unit breakdown voltage, the second amplification switching tube cut-in voltage and the 3rd resistor partial pressure sum；The over-pressed threshold
It is worth for the first voltage regulation unit breakdown voltage and the first amplification switching tube cut-in voltage sum.
Alternatively, the under-voltage/over-voltage protection circuit also includes the first indicator lamp and/or the first buzzer, wherein,
First indicator lamp and/or described first buzzer one end connect the anode of first voltage regulation unit and described
The common port of first resistor；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than overvoltage threshold, first voltage regulation unit is not hit
Wear, the voltage at the first amplification switch controlled end is zero, first indicator lamp and/or first buzzer not work
Make；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than overvoltage threshold, first voltage regulation unit punctures,
The voltage of the control terminal of the first amplification switching tube is high level, first indicator lamp and/or the first buzzer work
Make.
Alternatively, the circuit also includes the second indicator lamp and/or the second buzzer, wherein,
Second indicator lamp and/or described second buzzer one end connection it is described second amplification switching tube output end and
The common port of 7th resistance；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than the input of the second brownout threshold or the circuit
Voltage is more than the overvoltage threshold, the second amplification switching tube cut-off, the output end of the second amplification switching tube and described
The common port output high level of 7th resistance, second indicator lamp and/or second buzzer work；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than second brownout threshold and is less than overvoltage threshold,
The second amplification switching tube conducting, the output end of the second amplification switching tube and the common port output of the 7th resistance are low
Level, then second indicator lamp and/or second buzzer do not work.
Alternatively, first voltage regulation unit includes at least one voltage-stabiliser tube.
Alternatively, second voltage regulation unit includes at least one voltage-stabiliser tube.
Present invention also offers a kind of set top box, including under-voltage/over-voltage protection circuit, the under-voltage/over-voltage protection circuit includes：The
One voltage regulation unit, first resistor, second resistance, the first amplification switching tube, the second voltage regulation unit, 3rd resistor, the 4th resistance, the
Five resistance, the second amplification switching tube, the 6th resistance, the 7th resistance and controlling switch pipe, wherein,
The input of the under-voltage/over-voltage protection circuit is used for the negative electrode for connecting first voltage regulation unit, first voltage stabilizing
The anode of unit connects one end of the first resistor, and the other end ground connection of the first resistor, described second resistance one end connects
Connect the anode of first voltage regulation unit and the common port of the first resistor, the second resistance other end connection described first
Amplify the control terminal of switching tube, the input end grounding of the first amplification switching tube, the negative electrode connection of second voltage regulation unit
The input of the circuit, the anode of second voltage regulation unit connect one end of the 3rd resistor, the 3rd resistor
The output end of other end connection the first amplification switching tube, one end of the 4th resistance connect the 3rd resistor with it is described
The common port of the output end of first amplification switching tube, the other end ground connection of the 4th resistance, one end of the 5th resistance connects
Connect the common port of the 3rd resistor and the 4th resistance, other end connection the second amplification switch of the 5th resistance
The control terminal of pipe, the input end grounding of the second amplification switching tube, one end of the 6th resistance connects the defeated of the circuit
Enter to hold, one end of other end connection the 7th resistance of the 6th resistance, described in the other end connection of the 7th resistance
The output end of second amplification switching tube, the input of the circuit connect the control terminal of the controlling switch pipe, and the control is opened
The output end for closing pipe connects the common port of the 6th resistance and the 7th resistance, the input connection of the controlling switch pipe
Power supply；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than the first brownout threshold, first voltage regulation unit
All do not puncture with second voltage regulation unit, described first amplifies the defeated of the control terminal of switching tube and the second amplification switching tube
It is zero to enter voltage, the first amplification switching tube and the second amplification switching tube cut-off, the control of the controlling switch pipe
The voltage of input and the voltage of the control terminal of the controlling switch pipe are high level, the controlling switch pipe cut-off；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than first brownout threshold and under-voltage less than second
Threshold value, then first voltage regulation unit do not puncture, the input voltage of control terminal of the first amplification switching tube is zero, described the
One amplification switching tube cut-off, the second voltage regulation unit breakdown, the input terminal voltage are less than in the partial pressure of the 4th resistance
The cut-in voltage that the control terminal of the second amplification switching tube needs, then the second amplification switching tube cut-off, the control are opened
The voltage for closing the voltage of the control signal of pipe and the control terminal of the controlling switch pipe is high level, the controlling switch pipe
Cut-off；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than second brownout threshold and is less than overvoltage threshold,
Then first voltage regulation unit does not puncture, and the input voltage of the control terminal of the first amplification switching tube is zero, and described first puts
Big switching tube cut-off, the second voltage regulation unit breakdown, the input terminal voltage are more than described in the partial pressure of the 4th resistance
The cut-in voltage that the control terminal of second amplification switching tube needs, the second amplification switching tube conducting, the controlling switch pipe
The voltage of input is more than the voltage of the control terminal of the controlling switch pipe, then the controlling switch pipe conducting；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than the overvoltage threshold, first voltage regulation unit
Breakdown, the first amplification switching tube conducting, the input voltage of the control terminal of the second amplification switching tube is zero, described second
Amplify switching tube cut-off, the voltage of the control signal of the controlling switch pipe and the voltage of the control terminal of the controlling switch pipe
It is high level, the controlling switch pipe cut-off；Wherein,
First brownout threshold is the second voltage regulation unit breakdown voltage；Second brownout threshold is described second
Voltage regulation unit breakdown voltage, the second amplification switching tube cut-in voltage and the 3rd resistor partial pressure sum；The over-pressed threshold
It is worth for the first voltage regulation unit breakdown voltage and the first amplification switching tube cut-in voltage sum.
Alternatively, the set top box also includes the first indicator lamp and/or the first buzzer, wherein,
First indicator lamp and/or described first buzzer one end connect the anode of first voltage regulation unit and described
The common port of first resistor；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than overvoltage threshold, first voltage regulation unit is not hit
Wear, the voltage at the first amplification switch controlled end is zero, first indicator lamp and/or first buzzer not work
Make；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than overvoltage threshold, first voltage regulation unit punctures,
The voltage of the control terminal of the first amplification switching tube is high level, first indicator lamp and/or the first buzzer work
Make.
Alternatively, the set top box also includes the second indicator lamp and/or the second buzzer, wherein,
Second indicator lamp and/or described second buzzer one end connection it is described second amplification switching tube output end and
The common port of 7th resistance；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than the input of the second brownout threshold or the circuit
Voltage is more than the overvoltage threshold, the second amplification switching tube cut-off, the output end of the second amplification switching tube and described
The common port output high level of 7th resistance, second indicator lamp and/or second buzzer work；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than second brownout threshold and is less than overvoltage threshold,
The second amplification switching tube conducting, the output end of the second amplification switching tube and the common port output of the 7th resistance are low
Level, then second indicator lamp and/or second buzzer do not work.
Alternatively, first voltage regulation unit includes at least one voltage-stabiliser tube.
Alternatively, second voltage regulation unit includes at least one voltage-stabiliser tube.
Foregoing invention, when input voltage is less than the second brownout threshold or more than overvoltage threshold, under-voltage/over-voltage protection circuit
Controlling switch pipe is in cut-off state, disconnects the connection with power supply, only when input voltage is more than the second brownout threshold and is less than
During overvoltage threshold, controlling switch pipe is in the conduction state so that power supply can normally supply circuit, so as to realize to circuit
Under-voltage/over-voltage protection, prevent the electronic component in circuit due to owe overvoltage cause to damage.
Brief description of the drawings
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
There is the required accompanying drawing used in technology description to be briefly described, it should be apparent that, drawings in the following description are only this
Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, can be with
Other accompanying drawings are obtained according to these accompanying drawings.
Fig. 1 is a kind of structure chart of under-voltage/over-voltage protection circuit of the present invention；
Fig. 2 is a kind of another structure chart of under-voltage/over-voltage protection circuit of the present invention；
Fig. 3 is a kind of circuit theory diagrams of under-voltage/over-voltage protection circuit applied to set top box of the invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete
Site preparation describes, it is clear that described embodiment is only part of the embodiment of the present invention, rather than whole embodiments.It is based on
Embodiment in the present invention, those of ordinary skill in the art are obtained every other under the premise of creative work is not made
Embodiment, belong to the scope of protection of the invention.
It should be noted that the term used in embodiments of the present invention is only merely for the mesh of description specific embodiment
, and it is not intended to be limiting the present invention." one of singulative used in the embodiment of the present invention and appended claims
Kind ", " described " and "the" are also intended to including most forms, unless context clearly shows that other implications.It is also understood that this
Term "and/or" used herein refers to and comprising any or all possible group associated of list items purpose of one or more
Close.
Referring to Fig. 1, Fig. 1 is a kind of structure chart of under-voltage/over-voltage protection circuit of the present invention, a kind of under-voltage/over-voltage protection of the present invention
Circuit includes：First voltage regulation unit D1, first resistor R1, second resistance R2, the first amplification switching tube Q1, the second voltage regulation unit
D2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the second amplification switching tube Q2, the 6th resistance R6, the 7th resistance R7 with
And controlling switch pipe S, wherein,
The input of the under-voltage/over-voltage protection circuit is used for the negative electrode for connecting the first voltage regulation unit D1, the first voltage regulation unit D1's
Anode connection first resistor R1 one end, first resistor R1 other end ground connection, second resistance R2 one end connects the first voltage stabilizing list
First D1 anode and first resistor R1 common port, the first amplification switching tube of second resistance R2 other ends connection Q1 control terminal,
First amplification switching tube Q1 input end grounding, the input of the second voltage regulation unit D2 negative electrode connection circuit, the second voltage stabilizing list
First D2 anode connection 3rd resistor R3 one end, 3rd resistor R3 the first amplification switching tube of other end connection Q1 output
End, the common port of the 4th resistance R4 one end amplification switching tubes of connection 3rd resistor R3 and first Q1 output end, the 4th resistance
R4 other end ground connection, the 5th resistance R5 one end connection 3rd resistor R3 and the 4th resistance R4 common port, the 5th resistance R5
The second amplification of other end connection switching tube Q2 control terminal, the second amplification switching tube Q2 input end grounding, the 6th resistance R6
One end connection circuit input, the 6th resistance R6 other end connects the 7th resistance R7 one end, and the 7th resistance R7's is another
The second amplification switching tube of one end connection Q2 output end, the input connection controlling switch pipe S of circuit control terminal, controlling switch
Pipe S output end connection the 6th resistance R6 and the 7th resistance R7 common port, controlling switch pipe S input connection power supply.
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than the first brownout threshold, the first voltage regulation unit D1 and
Two voltage regulation unit D2 do not puncture, and the input voltage of the first amplification switching tube Q1 and the second amplification switching tube Q2 control terminal is
Zero, the first amplification switching tube Q1 and the second amplification switching tube Q2 cut-offs, the voltage of controlling switch pipe S control signal and control
The voltage of switching tube S control terminal is high level, and controlling switch pipe S ends.
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than the first brownout threshold and is less than the second brownout threshold,
First voltage regulation unit D1 does not puncture, and the input voltage of the first amplification switching tube Q1 control terminal is zero, the first amplification switching tube Q1
Cut-off, the second voltage regulation unit D2 breakdown, input terminal voltage are less than the second amplification switching tube Q2 control in the 4th resistance R4 partial pressure
The cut-in voltage that end processed needs, then the second amplification switching tube Q2 cut-offs, the voltage of controlling switch pipe S control signal and control
The voltage of switching tube S control terminal is high level, and controlling switch pipe S ends.
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than the second brownout threshold and is less than overvoltage threshold, first
Voltage regulation unit D1 does not puncture, and the input voltage of the first amplification switching tube Q1 control terminal is zero, the first amplification switching tube Q1 cut-offs,
Second voltage regulation unit D2 punctures, and the control terminal that input terminal voltage is more than the second amplification switching tube Q2 in the 4th resistance R4 partial pressure needs
The cut-in voltage wanted, the second amplification switching tube Q2 conductings, the voltage of controlling switch pipe S input is more than controlling switch pipe S's
The voltage of control terminal, then controlling switch pipe S conductings.
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than overvoltage threshold, the first voltage regulation unit D1 punctures, the
One amplification switching tube Q1 conductings, the input voltage of the second amplification switching tube Q2 control terminal is zero, and the second amplification switching tube Q2 is cut
Only, the voltage of controlling switch pipe S control signal and the voltage of controlling switch pipe S control terminal are high level, and control is opened
Close pipe S cut-offs.
It should be noted that above-mentioned first brownout threshold is the second voltage regulation unit D2 breakdown voltages；Second brownout threshold is
Second voltage regulation unit D2 breakdown voltages, the second amplification switching tube Q2 cut-in voltages and 3rd resistor R3 partial pressure sums；Overvoltage threshold
For the first voltage regulation unit D1 breakdown voltages and the first amplification switching tube Q1 cut-in voltage sums.
It should also be noted that, the first voltage regulation unit D1 or the second voltage regulation unit D2 include at least one voltage-stabiliser tube, when
When including multiple voltage-stabiliser tubes in the first voltage regulation unit D1 or the second voltage regulation unit D2, the negative electrode of first voltage-stabiliser tube is steady as first
The negative electrode of the voltage stabilizing list of cells D 1 or second is pressed, the anode of first voltage-stabiliser tube connects the negative electrode of second voltage-stabiliser tube, and second steady
The anode of pressure pipe connects the negative electrode of the 3rd voltage-stabiliser tube, and by that analogy, the anode of last voltage-stabiliser tube is as the first voltage stabilizing list
First D1 or the second voltage stabilizing list anode, the first voltage regulation unit D1 or the second voltage regulation unit D2 breakdown voltage are included equal to them
Each voltage-stabiliser tube breakdown voltage sum.Above-mentioned first amplification switching tube Q1 or the second amplification switching tube Q2 is included but extremely
A few triode, above-mentioned controlling switch pipe S include but is not limited to metal-oxide-semiconductor.
In the present embodiment, when input voltage is less than the second brownout threshold or more than overvoltage threshold, under-voltage/over-voltage protection electricity
The controlling switch pipe on road disconnects the connection with power supply, only when input voltage is more than the second brownout threshold all in cut-off state
And when being less than overvoltage threshold, controlling switch pipe is in the conduction state so that power supply can normally supply circuit, so as to realize pair
The under-voltage/over-voltage protection of circuit, prevent the electronic component in circuit due to owe overvoltage cause to damage.
Fig. 2 is referred to, Fig. 2 is a kind of another structure chart of under-voltage/over-voltage protection circuit of the present invention, and the circuit describes in Fig. 1
The first indicator lamp L1 and/or the first buzzer H1 and the second indicator lamp are added on the basis of under-voltage/over-voltage protection circuit structure chart
L2 and/or the second buzzer H2, it is to be in over-pressed shape intuitively to remind user's input voltage by indicator lamp and/or buzzer
State or under-voltage condition.
Specifically, the first indicator lamp L1 and/or first buzzer H1 one end connect the first voltage regulation unit D1 anode and the
One resistance R1 common port；Second indicator lamp L2 and/or the second amplification switching tube of second buzzer H2 one end connection Q2 output
End and the 7th resistance R7 common port.
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than the second brownout threshold, the first voltage regulation unit D1 is not hit
Wear, the voltage of the first amplification switching tube Q1 control terminals is zero, and the first indicator lamp L1 and/or the first buzzer H1 do not work；Second
Amplify switching tube Q2 to end, the second amplification switching tube Q2 output end and the 7th resistance R7 common port output high level, second
Indicator lamp L2 and/or the second buzzer H2 work, remind user's input voltage under-voltage.
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than the second brownout threshold and is less than overvoltage threshold, first is steady
Pressure cells D 1 does not puncture, and the voltage of the first amplification switching tube Q1 control terminals is zero, the first indicator lamp L1 and/or the first buzzer H1
Do not work；Second amplification switching tube Q2 conductings, the second amplification switching tube Q2 output end and the 7th resistance R7 common port output
Low level, then the second indicator lamp L2 and/or the second buzzer H2 do not work, remind user's input voltage in normal range (NR).
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than overvoltage threshold, the first voltage regulation unit D1 punctures, first
The voltage of amplification switching tube Q1 control terminal is high level, the first indicator lamp L1 and/or the first buzzer H1 work；Second amplification
Switching tube Q2 ends, the second amplification switching tube Q2 output end and the 7th resistance R7 common port output high level, the second instruction
Lamp L2 and/or the second buzzer H2 work, remind the overvoltage of user's input voltage.
It should be noted that above-mentioned the first indicator lamp L1 or the second indicator lamp L2 includes but is not limited to LED light, small
Small electric bulb etc., the first above-mentioned buzzer H1 or the second buzzer H2 include but is not limited to active buzzer, passive buzzer etc.
Deng.
In the present embodiment, when input voltage is less than the second brownout threshold, the controlling switch pipe S of under-voltage/over-voltage protection circuit
In cut-off state, the connection with power supply, the second indicator lamp and/or the work of the second buzzer are disconnected, reminds user's input voltage
It is under-voltage；When being more than overvoltage threshold when input voltage, the controlling switch pipe S of under-voltage/over-voltage protection circuit disconnects all in cut-off state
With the connection of power supply, the first indicator lamp and/or the work of the first buzzer, the second indicator lamp and/or the second buzzer also work, carried
User's input voltage of waking up is over-pressed；Only when input voltage is more than the second brownout threshold and is less than overvoltage threshold, switching tube is in
Conducting state so that power supply can normally supply circuit, so as to realize the under-voltage/over-voltage protection to circuit, prevent the electricity in circuit
Subcomponent causes to damage due to owing overvoltage, in addition, now the first indicator lamp and/or the first buzzer and the second indicator lamp
And/or second buzzer do not work, remind user's input voltage in normal range (NR).
Fig. 3 is referred to, a kind of circuit theory diagrams of under-voltage/over-voltage protection circuits applied to set top box of Fig. 3, this is owed overvoltage and protected
Protection circuit includes：First voltage-stabiliser tube DW1, the second voltage-stabiliser tube DW2, the first indicator lamp L1, the first buzzer H1, first resistor R1,
Second resistance R2, the first amplification switching tube Q1, the 3rd voltage-stabiliser tube DW3,3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the
Two amplification switching tube Q2, the 6th resistance R6, the 7th resistance R7, the second indicator lamp L2, the second buzzer H2 and controlling switch pipe
S, wherein, the first amplification switching tube Q1 is that the first triode QP1 is NPN type triode, and controlling switch pipe S is metal-oxide-semiconductor.
The input of the under-voltage/over-voltage protection circuit is used for the negative electrode for connecting the first voltage-stabiliser tube DW1, the first voltage-stabiliser tube DW1 sun
Pole connects the second voltage-stabiliser tube DW2 negative electrode, the second voltage-stabiliser tube DW2 anode connection first resistor R1 one end, first resistor R1
The other end ground connection, second resistance R2 one end connect the second voltage-stabiliser tube DW2 anode and first resistor R1 common port, second electricity
Hinder the first amplification switching tube of R2 other ends connection Q1 control terminal, the first amplification switching tube Q1 input end grounding, the 3rd voltage stabilizing
The input of pipe DW3 negative electrode connection circuit, the 3rd voltage-stabiliser tube DW3 anode connection 3rd resistor R3 one end, 3rd resistor
R3 the first amplification switching tube of other end connection Q1 output end, the 4th resistance R4 one end connection 3rd resistor R3 are put with first
The common port of big switching tube Q1 output end, the 4th resistance R4 other end ground connection, the 5th resistance R5 electricity of one end connection the 3rd
Resistance R3 and the 4th resistance R4 common port, the 5th resistance R5 the second amplification switching tube of other end connection Q2 control terminal, second
Amplify switching tube Q2 input end grounding, the input of the 6th resistance R6 one end connection circuit, the 6th resistance R6 other end
Connect the 7th resistance R7 one end, the 7th resistance R7 the second amplification switching tube of other end connection Q2 output end, circuit it is defeated
Enter end connection controlling switch pipe S control terminal, controlling switch pipe S output end connection the 6th resistance R6 and the 7th resistance R7 public affairs
End altogether, controlling switch pipe S input connection power supply.First indicator lamp L1 and/or the connection second of first buzzer H1 one end are steady
Pressure pipe DW2 anode and first resistor R1 common port A points；Second indicator lamp L2 and/or second buzzer H2 one end connection the
Two amplification switching tube Q2 output end and the 7th resistance R7 common port B points.
Specifically, when under-voltage/over-voltage protection circuit protection is applied to 12V power supply set top boxes, the first voltage-stabiliser tube DW1 or the
Two voltage-stabiliser tube DW2 breakdown voltages be all 6.9V, first resistor R1 resistances be 3.9K, second resistance R2 resistances are 10K, the first amplification
Switching tube Q1 cut-in voltages are 0.6V, the 3rd voltage-stabiliser tube DW3 breakdown voltages are 6.9V, 3rd resistor R3 resistances are 5.1K, the 4th
Resistance R4 resistances are 5.1K, the 5th resistance R5 resistances are 10K, the second amplification switching tube Q2 cut-in voltages are 0.6V, the 6th resistance
R6 resistances are 1K, the 7th resistance R7 resistances are 2K, the second indicator lamp L2, the second buzzer H2 and controlling switch pipe S, thus may be used
Know that the first brownout threshold is 6.9V, the second brownout threshold is 8.4V, overvoltage threshold 14.4V.The parameter of above-mentioned each device is only
It is applied to a kind of embodiment of the under-voltage/over-voltage protection of 12V voltages for a kind of under-voltage/over-voltage protection circuit of the present invention.
When the input terminal voltage of the 12V under-voltage/over-voltage protection circuits is less than the first brownout threshold 6.9V, then the first voltage-stabiliser tube
DW1, the second voltage-stabiliser tube DW2 and the 3rd voltage-stabiliser tube DW3 do not puncture, and the first amplification switching tube Q1 and second amplifies switching tube Q2's
The input voltage of control terminal is zero, the first amplification switching tube Q1 and the second amplification switching tube Q2 cut-offs, controlling switch pipe S control
The voltage of input processed and the voltage of controlling switch pipe S control terminal are high level, and controlling switch pipe S ends.
When the input terminal voltage of the 12V under-voltage/over-voltage protection circuits is more than the first brownout threshold 6.9V and is less than the second under-voltage threshold
Value 8.4V, then the first voltage-stabiliser tube DW1 and the second voltage-stabiliser tube DW2 do not puncture, the input electricity of the first amplification switching tube Q1 control terminal
Pressure is zero, the first amplification switching tube Q1 cut-offs, the 3rd voltage-stabiliser tube DW3 breakdown, and partial pressure of the input terminal voltage in the 4th resistance R4 is small
In the cut-in voltage 0.6V that the second amplification switching tube Q2 control terminal needs, then the second amplification switching tube Q2 cut-offs, controlling switch
The voltage of pipe S control signal and the voltage of controlling switch pipe S control terminal are high level, and controlling switch pipe S ends.
In above-mentioned two situations, the first voltage-stabiliser tube DW1 and the second voltage-stabiliser tube DW2 do not puncture, the first amplification switching tube Q1
The voltage of control terminal is zero, and the first indicator lamp L1 and/or the first buzzer H1 do not work；Second amplification switching tube Q2 cut-offs, the
Two amplification switching tube Q2 output end and the 7th resistance R7 common port output high level, the second indicator lamp L2 and/or the second honeybee
The device H2 that rings works, and reminds user's input voltage under-voltage.
When the input terminal voltage of the 12V under-voltage/over-voltage protection circuits is more than the second brownout threshold 8.4V and is less than overvoltage threshold
14.4V, then the first voltage-stabiliser tube DW1 and the second voltage-stabiliser tube DW2 do not puncture, the input voltage of the first amplification switching tube Q1 control terminal
It is zero, the first amplification switching tube Q1 cut-offs, the 3rd voltage-stabiliser tube DW3 punctures, and partial pressure of the input terminal voltage in the 4th resistance R4 is more than
The cut-in voltage 0.6V that second amplification switching tube Q2 control terminal needs, the second amplification switching tube Q2 conductings, controlling switch pipe S's
The voltage of control terminal of the voltage of input more than controlling switch pipe S, then controlling switch pipe S conductings.
Now, the first voltage-stabiliser tube DW1, the second voltage-stabiliser tube DW2 do not puncture, and the voltage of the first amplification switching tube Q1 control terminals is
Zero, the first indicator lamp L1 and/or the first buzzer H1 do not work；Second amplification switching tube Q2 conductings, the second amplification switching tube Q2
Output end and the 7th resistance R7 common port output low level, then the second indicator lamp L2 and/or the second buzzer H2 do not work,
User's input voltage is reminded in normal range (NR).
When the input terminal voltage of the 12V under-voltage/over-voltage protection circuits is more than overvoltage threshold 14.4V, then the first voltage-stabiliser tube DW1 and
Second voltage-stabiliser tube DW2 punctures, the first amplification switching tube Q1 conductings, and the input voltage of the second amplification switching tube Q2 control terminal is
Zero, the second amplification switching tube Q2 ends, the voltage of controlling switch pipe S control signal and controlling switch pipe S control terminal
Voltage is high level, and controlling switch pipe S ends.
Now, because the first voltage-stabiliser tube DW1, the second voltage-stabiliser tube DW2 puncture, the electricity of the first amplification switching tube Q1 control terminal
Press as high level, the first indicator lamp L1 and/or the first buzzer H1 work；Second amplification switching tube Q2 cut-offs, the second amplification are opened
Close pipe Q2 output end and the 7th resistance R7 common port output high level, the second indicator lamp L2 and/or the second buzzer H2 works
Make, remind the overvoltage of user's input voltage.
Following table lists the relation between the set top box power supply state and input voltage of 12V power supplies.
In the present embodiment, when input voltage is less than 8.4V or more than 14.4V, the controlling switch of under-voltage/over-voltage protection circuit
Pipe S disconnects the connection with power supply, only when input voltage is more than 8.4V and is less than 14.4V, control is opened all in cut-off state
It is in the conduction state to close pipe so that power supply can normally supply circuit, so as to realize that the deficient overvoltage to 12V power supply circuits is protected
Shield, prevent the electronic component in circuit due to owe overvoltage cause to damage.
Refer to Fig. 3, the circuit theory diagrams of a kind of under-voltage/over-voltage protection circuits applied to set top box of Fig. 3, when this owes overvoltage
When protection circuit protection is applied to 5V power supply set top boxes, the first voltage-stabiliser tube DW1 or the second voltage-stabiliser tube DW2 breakdown voltages be all 3V,
First resistor R1 resistances are 3.9K, second resistance R2 resistances are 10K, the first amplification switching tube Q1 cut-in voltages are 0.6V, the 3rd
Voltage-stabiliser tube DW3 breakdown voltages are 3V, 3rd resistor R3 resistances are 5.1K, the 4th resistance R4 resistances are 5.1K, the 5th resistance R5 resistances
Be worth for 10K, second amplification switching tube Q2 cut-in voltages be 0.6V, the 6th resistance R6 resistances are 1K, the 7th resistance R7 resistances be 2K,
Second indicator lamp L2, the second buzzer H2 and controlling switch pipe S, it can thus be appreciated that the first brownout threshold is 3V, the second under-voltage threshold
It is worth for 4.5V, overvoltage threshold 6.6V.The parameter of above-mentioned each device is only that a kind of under-voltage/over-voltage protection circuit of the present invention is applied to
A kind of embodiment of the under-voltage/over-voltage protection of 5V voltages.
When the input terminal voltage of the 5V under-voltage/over-voltage protection circuits is less than the first brownout threshold 3V, then the first voltage-stabiliser tube DW1,
Two voltage-stabiliser tube DW2 and the 3rd voltage-stabiliser tube DW3 do not puncture, the first amplification switching tube Q1 and the second amplification switching tube Q2 control terminal
Input voltage be zero, the first amplification switching tube Q1 and the second amplification switching tube Q2 cut-offs, controlling switch pipe S control input
The voltage at end and the voltage of controlling switch pipe S control terminal are high level, and controlling switch pipe S ends.
When the input terminal voltage of the 5V under-voltage/over-voltage protection circuits is more than the first brownout threshold 3V and is less than the second brownout threshold
4.5V, then the first voltage-stabiliser tube DW1 and the second voltage-stabiliser tube DW2 do not puncture, the input voltage of the first amplification switching tube Q1 control terminal
It is zero, the first amplification switching tube Q1 cut-offs, the 3rd voltage-stabiliser tube DW3 punctures, and partial pressure of the input terminal voltage in the 4th resistance R4 is less than
The cut-in voltage 0.6V that second amplification switching tube Q2 control terminal needs, then the second amplification switching tube Q2 cut-offs, controlling switch pipe S
The voltage and controlling switch pipe S voltage of control terminal of control signal be high level, controlling switch pipe S cut-offs.
In above-mentioned two situations, the first voltage-stabiliser tube DW1 and the second voltage-stabiliser tube DW2 do not puncture, the first amplification switching tube Q1
The voltage of control terminal is zero, and the first indicator lamp L1 and/or the first buzzer H1 do not work；Second amplification switching tube Q2 cut-offs, the
Two amplification switching tube Q2 output end and the 7th resistance R7 common port output high level, the second indicator lamp L2 and/or the second honeybee
The device H2 that rings works, and reminds user's input voltage under-voltage.
When the input terminal voltage of the 5V under-voltage/over-voltage protection circuits is more than the second brownout threshold 4.5V and is less than overvoltage threshold
6.6V, then the first voltage-stabiliser tube DW1 and the second voltage-stabiliser tube DW2 do not puncture, the input voltage of the first amplification switching tube Q1 control terminal
It is zero, the first amplification switching tube Q1 cut-offs, the 3rd voltage-stabiliser tube DW3 punctures, and partial pressure of the input terminal voltage in the 4th resistance R4 is more than
The cut-in voltage 0.6V that second amplification switching tube Q2 control terminal needs, the second amplification switching tube Q2 conductings, controlling switch pipe S's
The voltage of control terminal of the voltage of input more than controlling switch pipe S, then controlling switch pipe S conductings.
Now, the first voltage-stabiliser tube DW1, the second voltage-stabiliser tube DW2 do not puncture, and the voltage of the first amplification switching tube Q1 control terminals is
Zero, the first indicator lamp L1 and/or the first buzzer H1 do not work；Second amplification switching tube Q2 conductings, the second amplification switching tube Q2
Output end and the 7th resistance R7 common port output low level, then the second indicator lamp L2 and/or the second buzzer H2 do not work,
User's input voltage is reminded in normal range (NR).
When the input terminal voltage of the 5V under-voltage/over-voltage protection circuits is more than overvoltage threshold 6.6V, then the first voltage-stabiliser tube DW1 and
Two voltage-stabiliser tube DW2 puncture, and the first amplification switching tube Q1 conductings, the input voltage of the second amplification switching tube Q2 control terminal is zero,
Second amplification switching tube Q2 cut-offs, the voltage of controlling switch pipe S control signal and the voltage of controlling switch pipe S control terminal
It is high level, controlling switch pipe S ends.
Now, because the first voltage-stabiliser tube DW1, the second voltage-stabiliser tube DW2 puncture, the electricity of the first amplification switching tube Q1 control terminal
Press as high level, the first indicator lamp L1 and/or the first buzzer H1 work；Second amplification switching tube Q2 cut-offs, the second amplification are opened
Close pipe Q2 output end and the 7th resistance R7 common port output high level, the second indicator lamp L2 and/or the second buzzer H2 works
Make, remind the overvoltage of user's input voltage.
Following table lists the relation between set top box power supply state and input voltage.
In the present embodiment, when input voltage is less than 4.5V or more than 6.6V, the controlling switch of under-voltage/over-voltage protection circuit
Pipe S disconnects the connection with power supply, only when input voltage is more than 4.5V and is less than 6.6V, control is opened all in cut-off state
It is in the conduction state to close pipe so that power supply can normally supply circuit, so as to realize the under-voltage/over-voltage protection to 5V power supply circuits,
Prevent the electronic component in circuit due to owe overvoltage cause to damage.
Present invention also offers a kind of set top box, including under-voltage/over-voltage protection circuit, wherein, under-voltage/over-voltage protection circuit is as schemed
1st, the under-voltage/over-voltage protection circuit shown in Fig. 2 or Fig. 3, it is not reinflated herein referring specifically to Fig. 1, Fig. 2, Fig. 3 and associated description
Repeat.
One of ordinary skill in the art will appreciate that realize all or part of flow in above-described embodiment method, being can be with
The hardware of correlation is instructed to complete by computer program, described program can be stored in a computer read/write memory medium
In, the program is upon execution, it may include such as the flow of the embodiment of above-mentioned each method.Wherein, described storage medium can be magnetic
Dish, CD, read-only memory (Read-Only Memory, ROM) or random access memory (Random Access
Memory, RAM) etc..
The above disclosed power for being only a kind of preferred embodiment of the present invention, the present invention can not being limited with this certainly
Sharp scope, one of ordinary skill in the art will appreciate that realizing all or part of flow of above-described embodiment, and weighed according to the present invention
Profit requires made equivalent variations, still falls within and invents covered scope.
Claims (10)
1. a kind of under-voltage/over-voltage protection circuit, it is characterised in that the circuit includes：First voltage regulation unit, first resistor, the second electricity
Resistance, the first amplification switching tube, the second voltage regulation unit, 3rd resistor, the 4th resistance, the 5th resistance, the second amplification switching tube, the 6th
Resistance, the 7th resistance and controlling switch pipe, wherein,
The input of the under-voltage/over-voltage protection circuit is used for the negative electrode for connecting first voltage regulation unit, first voltage regulation unit
Anode connect one end of the first resistor, the other end ground connection of the first resistor, described second resistance one end connects institute
State the anode of the first voltage regulation unit and the common port of the first resistor, second resistance other end connection first amplification
The control terminal of switching tube, it is described first amplification switching tube input end grounding, second voltage regulation unit negative electrode connection described in
The input of circuit, the anode of second voltage regulation unit connect one end of the 3rd resistor, the 3rd resistor it is another
The output end of end connection the first amplification switching tube, one end of the 4th resistance connects the 3rd resistor and described first
Amplify the common port of the output end of switching tube, the other end ground connection of the 4th resistance, one end connection institute of the 5th resistance
The common port of 3rd resistor and the 4th resistance is stated, other end connection the second amplification switching tube of the 5th resistance
Control terminal, the input end grounding of the second amplification switching tube, one end of the 6th resistance connect the input of the circuit,
The other end of 6th resistance connects one end of the 7th resistance, and the other end connection described second of the 7th resistance is put
The output end of big switching tube, the input of the circuit connect the control terminal of the controlling switch pipe, the controlling switch pipe
Output end connects the common port of the 6th resistance and the 7th resistance, the input connection power supply of the controlling switch pipe；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than the first brownout threshold, first voltage regulation unit and institute
State the second voltage regulation unit all not puncture, the input electricity of the control terminal of the first amplification switching tube and the second amplification switching tube
Pressure is zero, the first amplification switching tube and the second amplification switching tube cut-off, the control input of the controlling switch pipe
The voltage at end and the voltage of the control terminal of the controlling switch pipe are high level, the controlling switch pipe cut-off；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than first brownout threshold and is less than the second brownout threshold,
Then first voltage regulation unit does not puncture, and the input voltage of the control terminal of the first amplification switching tube is zero, and described first puts
Big switching tube cut-off, the second voltage regulation unit breakdown, the input terminal voltage are less than described in the partial pressure of the 4th resistance
The cut-in voltage that the control terminal of second amplification switching tube needs, then the second amplification switching tube cut-off, the controlling switch pipe
The voltage of control terminal of voltage and the controlling switch pipe of control signal be high level, the controlling switch pipe is cut
Only；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than second brownout threshold and is less than overvoltage threshold, institute
State the first voltage regulation unit not puncture, the input voltage of the control terminal of the first amplification switching tube is zero, and first amplification is opened
Pipe cut-off, the second voltage regulation unit breakdown are closed, the input terminal voltage is more than described second in the partial pressure of the 4th resistance
Amplify the cut-in voltage that the control terminal of switching tube needs, the second amplification switching tube conducting, the input of the controlling switch pipe
The voltage at end is more than the voltage of the control terminal of the controlling switch pipe, then the controlling switch pipe conducting；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than the overvoltage threshold, first voltage regulation unit is hit
Wear, the first amplification switching tube conducting, the input voltage of the control terminal of the second amplification switching tube is zero, and described second puts
Big switching tube cut-off, the voltage of the control signal of the controlling switch pipe and the voltage of the control terminal of the controlling switch pipe are equal
For high level, the controlling switch pipe cut-off；Wherein,
First brownout threshold is the second voltage regulation unit breakdown voltage；Second brownout threshold is second voltage stabilizing
Unit breakdown voltage, the second amplification switching tube cut-in voltage and the 3rd resistor partial pressure sum；The overvoltage threshold is
The first voltage regulation unit breakdown voltage and the first amplification switching tube cut-in voltage sum.
2. under-voltage/over-voltage protection circuit according to claim 1, it is characterised in that the circuit also includes the first indicator lamp
And/or first buzzer, wherein,
First indicator lamp and/or described first buzzer one end connect the anode and described first of first voltage regulation unit
The common port of resistance；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than overvoltage threshold, first voltage regulation unit does not puncture, institute
The voltage for stating the first amplification switch controlled end is zero, and first indicator lamp and/or first buzzer do not work；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than overvoltage threshold, the first voltage regulation unit breakdown is described
The voltage of the control terminal of first amplification switching tube is high level, first indicator lamp and/or first buzzer work.
3. under-voltage/over-voltage protection circuit according to claim 2, it is characterised in that the circuit also includes the second indicator lamp
And/or second buzzer, wherein,
Second indicator lamp and/or described second buzzer one end connection second amplification output end of switching tube and described
The common port of 7th resistance；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than the input terminal voltage of the second brownout threshold or the circuit
More than the overvoltage threshold, the second amplification switching tube cut-off, the output end and the described 7th of the second amplification switching tube
The common port output high level of resistance, second indicator lamp and/or second buzzer work；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than second brownout threshold and is less than overvoltage threshold, described
Second amplification switching tube conducting, the output end of the second amplification switching tube and the common port of the 7th resistance export low electricity
Flat, then second indicator lamp and/or second buzzer do not work.
4. under-voltage/over-voltage protection circuit according to claim 3, it is characterised in that first voltage regulation unit includes at least one
Individual voltage-stabiliser tube.
5. under-voltage/over-voltage protection circuit according to claim 3, it is characterised in that second voltage regulation unit includes at least one
Individual voltage-stabiliser tube.
6. a kind of set top box, it is characterised in that including under-voltage/over-voltage protection circuit, the under-voltage/over-voltage protection circuit includes：First is steady
Press unit, first resistor, second resistance, the first amplification switching tube, the second voltage regulation unit, 3rd resistor, the 4th resistance, the 5th electricity
Resistance, the second amplification switching tube, the 6th resistance, the 7th resistance and controlling switch pipe, wherein,
The input of the under-voltage/over-voltage protection circuit is used for the negative electrode for connecting first voltage regulation unit, first voltage regulation unit
Anode connect one end of the first resistor, the other end ground connection of the first resistor, described second resistance one end connects institute
State the anode of the first voltage regulation unit and the common port of the first resistor, second resistance other end connection first amplification
The control terminal of switching tube, it is described first amplification switching tube input end grounding, second voltage regulation unit negative electrode connection described in
The input of circuit, the anode of second voltage regulation unit connect one end of the 3rd resistor, the 3rd resistor it is another
The output end of end connection the first amplification switching tube, one end of the 4th resistance connects the 3rd resistor and described first
Amplify the common port of the output end of switching tube, the other end ground connection of the 4th resistance, one end connection institute of the 5th resistance
The common port of 3rd resistor and the 4th resistance is stated, other end connection the second amplification switching tube of the 5th resistance
Control terminal, the input end grounding of the second amplification switching tube, one end of the 6th resistance connect the input of the circuit,
The other end of 6th resistance connects one end of the 7th resistance, and the other end connection described second of the 7th resistance is put
The output end of big switching tube, the input of the circuit connect the control terminal of the controlling switch pipe, the controlling switch pipe
Output end connects the common port of the 6th resistance and the 7th resistance, the input connection power supply of the controlling switch pipe；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than the first brownout threshold, first voltage regulation unit and institute
State the second voltage regulation unit all not puncture, the input electricity of the control terminal of the first amplification switching tube and the second amplification switching tube
Pressure is zero, the first amplification switching tube and the second amplification switching tube cut-off, the control input of the controlling switch pipe
The voltage at end and the voltage of the control terminal of the controlling switch pipe are high level, the controlling switch pipe cut-off；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than first brownout threshold and is less than the second brownout threshold,
Then first voltage regulation unit does not puncture, and the input voltage of the control terminal of the first amplification switching tube is zero, and described first puts
Big switching tube cut-off, the second voltage regulation unit breakdown, the input terminal voltage are less than described in the partial pressure of the 4th resistance
The cut-in voltage that the control terminal of second amplification switching tube needs, then the second amplification switching tube cut-off, the controlling switch pipe
The voltage of control terminal of voltage and the controlling switch pipe of control signal be high level, the controlling switch pipe is cut
Only；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than second brownout threshold and is less than overvoltage threshold, institute
State the first voltage regulation unit not puncture, the input voltage of the control terminal of the first amplification switching tube is zero, and first amplification is opened
Pipe cut-off, the second voltage regulation unit breakdown are closed, the input terminal voltage is more than described second in the partial pressure of the 4th resistance
Amplify the cut-in voltage that the control terminal of switching tube needs, the second amplification switching tube conducting, the input of the controlling switch pipe
The voltage at end is more than the voltage of the control terminal of the controlling switch pipe, then the controlling switch pipe conducting；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than the overvoltage threshold, first voltage regulation unit is hit
Wear, the first amplification switching tube conducting, the input voltage of the control terminal of the second amplification switching tube is zero, and described second puts
Big switching tube cut-off, the voltage of the control signal of the controlling switch pipe and the voltage of the control terminal of the controlling switch pipe are equal
For high level, the controlling switch pipe cut-off；Wherein,
First brownout threshold is the second voltage regulation unit breakdown voltage；Second brownout threshold is second voltage stabilizing
Unit breakdown voltage, the second amplification switching tube cut-in voltage and the 3rd resistor partial pressure sum；The overvoltage threshold is
The first voltage regulation unit breakdown voltage and the first amplification switching tube cut-in voltage sum.
7. set top box according to claim 6, it is characterised in that the set top box also includes the first indicator lamp and/or the
One buzzer, wherein,
First indicator lamp and/or described first buzzer one end connect the anode and described first of first voltage regulation unit
The common port of resistance；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than overvoltage threshold, first voltage regulation unit does not puncture, institute
The voltage for stating the first amplification switch controlled end is zero, and first indicator lamp and/or first buzzer do not work；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than overvoltage threshold, the first voltage regulation unit breakdown is described
The voltage of the control terminal of first amplification switching tube is high level, first indicator lamp and/or first buzzer work.
8. set top box according to claim 7, it is characterised in that the set top box also includes the second indicator lamp and/or the
Two buzzers, wherein,
Second indicator lamp and/or described second buzzer one end connection second amplification output end of switching tube and described
The common port of 7th resistance；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is less than the input terminal voltage of the second brownout threshold or the circuit
More than the overvoltage threshold, the second amplification switching tube cut-off, the output end and the described 7th of the second amplification switching tube
The common port output high level of resistance, second indicator lamp and/or second buzzer work；
If the input terminal voltage of the under-voltage/over-voltage protection circuit is more than second brownout threshold and is less than overvoltage threshold, described
Second amplification switching tube conducting, the output end of the second amplification switching tube and the common port of the 7th resistance export low electricity
Flat, then second indicator lamp and/or second buzzer do not work.
9. set top box according to claim 8, it is characterised in that first voltage regulation unit includes at least one voltage stabilizing
Pipe.
10. set top box according to claim 8, it is characterised in that second voltage regulation unit includes at least one voltage stabilizing
Pipe.
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| CN105591356A (en) * | 2016-03-07 | 2016-05-18 | 青岛歌尔声学科技有限公司 | Overvoltage and undervoltage protection circuit |
| CN105634263A (en) * | 2016-04-12 | 2016-06-01 | 上海斐讯数据通信技术有限公司 | Protection circuit self-adaptive to input voltage |
| CN206452095U (en) * | 2016-12-08 | 2017-08-29 | 深圳创维数字技术有限公司 | A kind of over under-voltage protection circuit and set top box |
| CN106993149B (en) * | 2017-03-23 | 2019-08-13 | 深圳市金锐显数码科技有限公司 | LVDS output protection and prevent hot plugging circuit and LVDS transmission module |
| CN107359597B (en) * | 2017-07-18 | 2019-01-25 | 中国电子科技集团公司第二十四研究所 | Circuit is protected for the over-and under-voltage between production line analog-digital converter grade |
| US11332592B2 (en) | 2017-09-27 | 2022-05-17 | Advansix Resins & Chemicals Llc | Method for preparing extruded polyamide foams |
| CN109936287A (en) * | 2017-12-16 | 2019-06-25 | 厦门新页科技有限公司 | A kind of voltage regulator circuit with input undervoltage, overvoltage protection |
| CN109342973B (en) * | 2018-11-19 | 2022-01-18 | 中车大连电力牵引研发中心有限公司 | Direct current power supply input state monitoring circuit and system |
| CN114355027B (en) * | 2022-03-17 | 2022-06-14 | 深圳市芯卓微科技有限公司 | Detection circuit and chip |
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