CN2796208Y - Over-power protector - Google Patents
Over-power protector Download PDFInfo
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- CN2796208Y CN2796208Y CNU2005200045598U CN200520004559U CN2796208Y CN 2796208 Y CN2796208 Y CN 2796208Y CN U2005200045598 U CNU2005200045598 U CN U2005200045598U CN 200520004559 U CN200520004559 U CN 200520004559U CN 2796208 Y CN2796208 Y CN 2796208Y
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Abstract
The utility model provides an over-power protector, which comprises an oscillator for outputting a frequency signal, an over-power signal picking comparing unit for outputting a protection signal, a progressive triggering unit for outputting a disabling signal, a latch unit for receiving the disabling signal and outputting a latch signal, a driving signal generating unit for receiving the frequency signal and the latch signal and a driving signal control unit for receiving a sensing signal and a second critical signal, wherein the progressive triggering unit is connected with the over-power signal picking comparing unit and the oscillator and connects the frequency signal and the protection signal; the latch unit is connected to the progressive triggering unit; the driving signal generating unit is connected to the latch unit and the oscillator; the latch signal stops outputting a driving signal to a power switch; the driving signal control unit is connected to the driving signal generating unit. When the sensing signal rises to the second critical signal, the driving signal control unit outputs a clear signal to the driving signal generating unit to stop the driving signal to the power switch.
Description
Technical field
The utility model relates to a kind of overpower protection, particularly relates to a kind of overpower protection that is applied to power supply unit.
Background technology
Various power supply units can provide stable voltage and the electric current of adjusting at present.In order to meet the consideration of safety (safety); power supply unit still must provide the overpower protection function; to guarantee between the misoperation emergence periods such as overload, short circuit and feedback open circuit, protect power supply unit itself and power-supply system end to reach by the restriction power output.
Please refer to Fig. 1, be known power supply unit schematic diagram.Power supply unit includes a transformer T at least
1, a drive signal control unit 14, a drive signal generation unit 10, an oscillator 12 and a power switch Q
1Transformer T
1Primary side switch current I
PThe current sensing resistor R that flows through
SLast generation one current sensing signal V
CS, can obtain a feedback signal V from the output of power supply unit simultaneously
FBDrive signal control unit 14 is made up of a linkage unit 144, a Power Limitation comparator 146 and a PWM comparator 148.Power Limitation comparator 146 is connected to current sensing resistor R simultaneously with an input of PWM comparator 148
STo obtain current sensing signal V
CSAnother input of Power Limitation comparator 146 then connects a maximum power signal V
LMT, another input of PWM comparator 148 then connects the output of power supply unit to obtain feedback signal V
FBAs current sensing signal V
CSGreater than maximum power signal V
LMTThe time, Power Limitation comparator 146 outputs are exported an overcurrent signal OC, and, as current sensing signal V
CSGreater than feedback signal V
FBThe time, PWM comparator 148 outputs one feedback control signal CNTR.Overcurrent signal OC and feedback control signal CNTR by linkage unit 144 in order to export a clear signal CLR.
The frequency signal CLK of driving signal generator 10 reception oscillators 12 outputs and the clear signal CLR of drive signal control unit 14 outputs, and then produce a drive signal V
PWMAs power controlling switch Q
1Switching.
Drive signal control unit 14 is according to current sensing signal V
CSBe higher than feedback signal V
FBThe feedback control signal CNTR of time output, or current sensing signal V
CSBe higher than maximum power signal V
LMTThe overcurrent signal OC of time output, and then adjust the output that changes clear signal CLR is with the controlling and driving signal generator 10 drive signal V that periodically stops using
PWM, allow the output of power supply unit obtain stable the adjustment, and also will limit the primary side current and the peak power output of power supply unit.
Yet; in the application of reality; power supply unit as printer and scanner etc.; must supply bigger power output so that the detent torque of motor to be provided starting moment; switching controller was often judged by accident and was overcurrent and overpowering misoperation generation this moment, and made power supply unit carry out unsuitable protection action.Known power supply unit when the design peak power output, often must adopt the design of specification in order to meet the load request that these have motor characteristics.That is to say, known power supply unit must provide peak power, and continue one section special time and have the load of motor characteristics to these, and this peak power usually is more than the multiple of peak power output, cause necessary booster tension of main power switch and some withstand voltage assemblies of anti-stream and current stress, and then make cost improve.Therefore, how to provide power supply unit to do suitable protection, and avoid the erroneous judgement of misoperation situation, real is important problem.
Summary of the invention
The purpose of this utility model is to provide a kind of overpower protection; be applied in the power supply unit; confirm that by different comparative levels power supply unit has misoperations such as overload, short circuit or feedback open circuit and produces; count the duration that misoperation takes place via progression again; arrive a default value when the duration of taking place; the utility model overpower protection can provide the drive signal that periodicity is ended or breech lock ends power supply unit, to protect action.
In order to achieve the above object, the utility model provides a kind of overpower protection, is used in the power supply unit, obtains a sensing signal, has drawn together: an oscillator, export a frequency signal; One overpower signal acquisition comparing unit captures this sensing signal and it and a minimum detectable signal is compared computing, in order to export a guard signal; One progression trigger element is connected in this overpower signal acquisition comparing unit and this oscillator, receives this guard signal and this frequency signal, exports a pick-off signal; One latch lock unit is connected in this progression trigger element, receives this pick-off signal, exports a latch-up signal; One drive signal generation unit is connected in this latch lock unit and this oscillator, receives this frequency signal and this latch-up signal, and this latch-up signal is in order to stop to export a drive signal to a power switch; An and drive signal control unit, be connected in this drive signal generation unit, receive this sensing signal and second minimum detectable signal, when this sensing signal rises to this second minimum detectable signal, the drive signal control unit is exported a clear signal to this drive signal generation unit, in order to arrive this power switch by this drive signal; Wherein, this guard signal is counted in this progression trigger element progression, wait the counting of this guard signal to arrive a default value after, this latch lock unit is controlled this drive signal generation unit, in order to breech lock by this drive signal to this power switch.
According to design of the present utility model; this overpower protection further includes a reset cell and is connected in this latch lock unit and this oscillator; receive this frequency signal and this latch-up signal; and after receiving this latch-up signal in the setting-up time; export a reset signal to this latch lock unit, in order to this latch lock unit of resetting.
According to design of the present utility model, this reset cell further connects a supply voltage, receives a low voltage signal after restarting power supply according to this power supply unit, to export a reset signal to this latch lock unit, in order to this latch lock unit of resetting.
According to design of the present utility model, this overpower signal acquisition comparing unit is a current comparator, and comparison operation one first minimum detectable signal and a current sensing signal are in order to export one first guard signal to this progression trigger element.
According to design of the present utility model, this overpower signal acquisition comparing unit is a voltage comparator, and comparison operation 1 the 3rd minimum detectable signal and a Voltage Feedback sensing signal are in order to export one second guard signal to this progression trigger element.
According to design of the present utility model, this overpower signal acquisition comparing unit includes: a current comparator, and comparison operation one first minimum detectable signal and a current sensing signal are in order to export one first guard signal; One voltage comparator, comparison operation 1 the 3rd minimum detectable signal and a Voltage Feedback sensing signal are in order to export one second guard signal; And a linkage unit, be connected in this current comparator, this voltage comparator and this progression trigger element, this first guard signal and this second guard signal are sent to this progression trigger element.
According to design of the present utility model, this progression trigger element includes: one keeps the unit, is connected to this overpower signal acquisition comparing unit and this oscillator, receives this guard signal and this frequency signal, in order to postponing the state of this guard signal, and export signal about in the of; And a counting unit up and down, be connected to this and keep unit and this oscillator, receive up and down signal and this frequency signal counting computing, and when downward counting finishes, stop counting, when upwards counting end, export this pick-off signal.
According to design of the present utility model, counting unit up and down, according to this up and down signal enable the counting that make progress, and according to this stopping using of signal and downward counting the up and down.
According to design of the present utility model, this progression trigger element, include: one keeps the unit, be connected to this overpower signal acquisition comparing unit and this oscillator, receive this guard signal and this frequency signal, in order to postponing the state of this guard signal, and export signal about in the of; Whether one switches switch, is connected to this and keeps the unit, receives signal up and down, and enable according to this guard signal and to export conducting or cut-off state; One variable capacitance, be connected to a charging current source by this diverter switch, conducting state according to this diverter switch obtains a charging current, in order to export a charging voltage, this variable capacitance also is connected to a discharging current source by this diverter switch, this discharging current source provides a discharging current according to the cut-off state of this diverter switch, in order to this variable capacitance is discharged; And a delay comparator, be connected to this variable capacitance and one the 4th minimum detectable signal, by relatively this charging voltage and the 4th minimum detectable signal, and produce this pick-off signal during greater than the 4th minimum detectable signal in this charging voltage.
The utility model overpower protection includes an oscillator and exports a frequency signal; simultaneously; use an overpower signal acquisition comparing unit to capture a sensing signal and a minimum detectable signal, after comparison operation sensing signal and minimum detectable signal, export a guard signal.Guard signal is sent to a progression trigger element.This guard signal is counted in the progression of progression trigger element; after waiting the counting of this guard signal to arrive a default value; promptly export a pick-off signal to a latch lock unit, latch lock unit produces a latch-up signal to a drive signal generation unit, in order to stop output drive signal to power switch.
The utility model overpower protection not only provides power supply unit when different misoperation (overload, short circuit and feedback open circuit etc.) takes place; impel power supply unit to produce the protection action; more can count the duration that misoperation takes place, protect improperly when the big rated output power of special time domestic demand in order to avoid load end by progression.Therefore the utility model overpower protection circuit can provide power supply to supply complete protection scheme in fact.
Above general introduction and ensuing detailed description are all exemplary in nature, are in order to further specify the protection range of patent of the present utility model.And about other purpose of the present utility model and advantage, will be set forth in follow-up explanation and accompanying drawing.
Description of drawings
Fig. 1 is known power supply unit schematic diagram;
Fig. 2 is the utility model circuit framework schematic diagram;
Fig. 3 is the utility model first embodiment circuit box schematic diagram;
Fig. 4 is the utility model circuit waveform schematic diagram;
Fig. 5 is the utility model second embodiment circuit box schematic diagram;
Fig. 6 is the utility model the 3rd embodiment circuit box schematic diagram;
Fig. 7 is an embodiment circuit box schematic diagram of the utility model progression trigger element;
Fig. 8 is another embodiment circuit box schematic diagram of the utility model progression trigger element; And
Fig. 9 is a reset cell circuit box schematic diagram of the present utility model.
Wherein, description of reference numerals is as follows:
Known:
Transformer T
1Drive signal generation unit 10
Sensing resistor R
SCurrent sensing signal V
CS
Feedback signal V
FBMaximum power signal V
LMT
Overcurrent signal OC feedback control signal CNTR
Arteries and veins signal CLK drive signal V
PWM
Power switch Q
1Supply voltage V
TN
Clear signal CLR
The utility model:
Overpower signal acquisition comparing unit 23 reset cells 24
Drive signal control unit 25 progression trigger elements 28
Current sensing signal V
CSVoltage Feedback sensing signal V
FB
The second minimum detectable signal V
T2Reset signal RST
Drive signal generation unit 10a frequency signal CLK
Drive signal V
PWMPower switch Q
1
Guard signal S
PTPick-off signal S
OFF
Latch-up signal LATCH supply voltage V
DD
The first guard signal S
PT1Voltage comparator 232
The 3rd minimum detectable signal V
T3The second guard signal S
PT2
Linkage unit is counting unit 282 about in the of 233
Keep unit 284 D flip- flops 2842,2844
The 4th minimum detectable signal V
T4 Diverter switch 283
Charging current source 288 discharging current sources 289
Transistor 2401,2402,2403,2412,2414
Inverter 2404,2405,2417
Electric capacity 2413 constant current sources 2411
NAND door 2415,2416 timer 2s 418
Clear signal CLR
Embodiment
Please refer to Fig. 2, be the utility model circuit framework schematic diagram.The utility model overpower protection is used in the power supply unit, includes: an overpower signal acquisition comparing unit 23 acquisition one sensing signals also compare computing with it and a minimum detectable signal, in order to produce a guard signal S
PTOne progression trigger element 28 is connected in an overpower signal acquisition comparing unit 23 and an oscillator 22, is used for receiving guard signal S according to a frequency signal CLK
PT, with progression counting guard signal S
PT, guard signal S
PTCounting arrive a default value after, progression trigger element 28 can output one pick-off signal S
OFFOne latch lock unit 21 is connected in progression trigger element 28, receives pick-off signal S
OFF, export a latch-up signal LATCH; One drive signal generation unit 10a is connected in latch lock unit 21 and oscillator 22, and receiving frequency signals CLK and latch-up signal LATCH are in order to stop to export a drive signal V
PWMTo a power switch Q
1To reach overpower protection; Reach a drive signal control unit 25 and be connected in drive signal generation unit 10a, receive a current sensing signal V
CS, a Voltage Feedback sensing signal V
FBWith one second minimum detectable signal V
T2, the second minimum detectable signal V
T2Limits value for the power supply unit peak power output.As current sensing signal V
CSRise to the second minimum detectable signal V
T2The time or as current sensing signal V
CSRise to Voltage Feedback sensing signal V
FBThe time, drive signal control unit 25 can arrive drive signal generation unit 10a by output one clear signal CLR, in order to periodically to end drive signal V
PWMTo power switch Q
1, to reach overpower protection.
With reference to figure 2, wherein the utility model overpower protection further includes a reset cell 24 and is connected in a supply voltage V again
DD, latch lock unit 21 and oscillator 22, receiving frequency signals CLK and latch-up signal LATCH, and behind reception latch-up signal LATCH, in the setting-up time, export a reset signal RST to latch lock unit 21, in order to the output of replacement latch lock unit 21.Reset cell 24 further connects a supply voltage V
DD, and in supply voltage V
DDWhen the voltage that provides is not enough, receive a low voltage signal, to export reset signal RST to latch lock unit 21.
Cooperate Fig. 2, Fig. 3 is the utility model first embodiment circuit box schematic diagram.Wherein this overpower signal acquisition comparing unit 23 is a current comparator 231, and an input of current comparator 231 receives one first minimum detectable signal V
T1, another input receives a current sensing signal V
CS, the comparison operation first minimum detectable signal V
T1With current sensing signal V
CS, in order to export one first guard signal S
PT1To progression trigger element 28.
When power supply unit need provide high power output, current sensing signal V
CSValue also can be relative raising, therefore in this first embodiment, utilize this corresponding relation, use a current comparator 231 as overpower signal acquisition comparing unit 23, design the first minimum detectable signal V simultaneously
T1Value adjust the critical restriction of power supply unit power output.As current sensing signal V
CSValue greater than the first minimum detectable signal V
T1The time, current comparator 231 can the primary first guard signal S of output
PT1To this progression trigger element 28,28 of progression this moment trigger elements carry out the first guard signal S
PT1Progression counting, as the first guard signal S
PT1Counting is promptly exported a pick-off signal S after arriving a default value
OFFTo this latch lock unit 21,, make drive signal generation unit 10a stop output drive signal V so that drive signal generation unit 10a is carried out breech lock
PWMTo power switch Q
1, protect improperly when the big rated output power of special time domestic demand to avoid load end, reach the overpower protection of power supply unit reality.Cooperate Fig. 3, Fig. 4 is the utility model circuit waveform schematic diagram.When power supply unit provided power output to use to load, drive signal generation unit 10a can export the drive signal V of high potential
PWMMake power switch Q
1So conducting is in time T
1～T
2The time, current sensing signal V
CSCan increase gradually.In time T
2The time, current sensing signal V
CSCan push up the first minimum detectable signal V
T1, the first guard signal S of current comparator 231 outputs this moment one electronegative potential
PT1To progression trigger element 28.Then, progression trigger element 28 begins to carry out the action of progression counting, to prepare that drive signal generation unit 10a is carried out breech lock.
Moreover, in time T
2～T
3The time, drive signal V
PWMMake power switch Q
1Continue conducting, current sensing signal V
CSContinue to rise, and in time T
3The time, current sensing signal V
CSCan push up the second minimum detectable signal V
T2, this moment, the overpower signal OC of electronegative potentials was exported in 25 meetings of drive signal control unit, and the clear signal CLR that also exports electronegative potential simultaneously makes drive signal V to drive signal generation unit 10a
PWMBe electronegative potential, and then make power switch Q
1By (time T
3～T
4), to provide periodically by drive signal V
PWMTo power switch Q
1
In the above-mentioned explanation, when the utility model first embodiment provides power output to use to load at power supply unit, by periodic current sensing signal V
CSPush up the first minimum detectable signal V
T1Duration arrive the default value of progression trigger element 28 after, the utility model overpower protection promptly can stop output drive signal V
PWMTo power switch Q
1, to reach the overpower protection of power supply unit reality.
Cooperate Fig. 2, Fig. 5 is the utility model second embodiment circuit box schematic diagram.Wherein this overpower signal acquisition comparing unit 23 is a voltage comparator 232, and an input of voltage comparator 232 receives one the 3rd minimum detectable signal V
T3, another input receives a Voltage Feedback sensing signal V
FB, comparison operation the 3rd minimum detectable signal V
T3With this Voltage Feedback sensing signal V
FB, in order to export one second guard signal S
PT2To this progression trigger element 28.
When power supply unit need provide high power output, Voltage Feedback sensing signal V
FBValue also can be relative raising, therefore in this second embodiment, utilize this corresponding relation, use a voltage comparator 232, design the 3rd minimum detectable signal V simultaneously
T3Value adjust the critical restriction of power supply unit power output.As Voltage Feedback sensing signal V
FBValue greater than the 3rd minimum detectable signal V
T3The time, voltage comparator 232 can the primary second guard signal S of output
PT2To this progression trigger element 28,28 of progression this moment trigger elements carry out the second guard signal S
PT2Progression counting.As the second guard signal S
PT2Counting is promptly exported a pick-off signal S after arriving a default value
OFFTo this latch lock unit 21,, make drive signal generation unit 10a stop output drive signal V so that drive signal generation unit 10a is carried out breech lock
PWMTo power switch Q
1, protect improperly when the big rated output power of special time domestic demand to avoid load end, reach the overpower protection of power supply unit reality.
In the above-mentioned explanation, when the utility model second embodiment provides power output to use to load at power supply unit, by periodic Voltage Feedback sensing signal V
FBPush up the 3rd minimum detectable signal V
T3Duration arrive the default value of progression trigger element 28 after, the utility model overpower protection can stop output drive signal V
PWMTo power switch Q
1, to reach the overpower protection of power supply unit reality.Moreover, circuit operation principle and the waveform thereof of the utility model second embodiment, itself and first embodiment compare, only the guard signal S that receives at progression trigger element 28
PTOutside the difference of source, all the other are all identical, do not add at this and give unnecessary details.
Cooperate Fig. 2, Fig. 6 is the utility model the 3rd embodiment circuit box schematic diagram.Wherein this overpower signal acquisition comparing unit 23 is connected to form by a current comparator 231, a voltage comparator 232 and a linkage unit 233.Current comparator 231 comparison operations one first minimum detectable signal V
T1With a current sensing signal V
CS, in order to produce one first guard signal S
PT1Voltage comparator 232 comparison operations 1 the 3rd minimum detectable signal V
T3With a Voltage Feedback sensing signal V
FB, in order to produce one second guard signal S
PT2Linkage unit 233 is connected in this current comparator 231, this voltage comparator 232 and this progression trigger element 28, with this first guard signal S
PT1With this second guard signal S
PT2Be sent to this progression trigger element 28.
When power supply unit need provide high power output, current sensing signal V
CSWith Voltage Feedback sensing signal V
FBValue also can be relative raising, therefore in this 3rd embodiment, utilizing this corresponding relation, use an overpower signal acquisition comparing unit 23 of being formed by current comparator 231, voltage comparator 232 and linkage unit 233, design this first minimum detectable signal V simultaneously
T1With the 3rd minimum detectable signal V
T3Value adjust the critical restriction of power supply unit power output.
As current sensing signal V
CSValue greater than the first minimum detectable signal V
T1, current comparator 231 produces the first guard signal S
PT1Or as Voltage Feedback sensing signal V
FBValue greater than the 3rd minimum detectable signal V
T3The time, voltage comparator 232 also can produce the second guard signal S
PT2The first guard signal S
PT1With the second guard signal S
PT2Form guard signal S by linkage unit 233
PT, being sent to this progression trigger element 28 then, 28 of progression this moment trigger elements carry out guard signal S
PTProgression counting.As guard signal S
PTCounting is promptly exported a pick-off signal S after arriving a default value
OFFTo this latch lock unit 21,, make drive signal generation unit 10a stop output drive signal V so that drive signal generation unit 10a is carried out breech lock
PWMTo power switch Q
1, protect improperly when the big rated output power of special time domestic demand to avoid load end, reach the overpower protection of power supply unit reality.
In the above-mentioned explanation, when the utility model the 3rd embodiment provides power output to use to load at power supply unit, by periodic current sensing signal V
CSPush up the first minimum detectable signal V
T1Duration and Voltage Feedback sensing signal V
FBPush up the 3rd minimum detectable signal V
T3Duration judge whether power supply unit has overpowering phenomenon, if after the duration arrived the default value of progression trigger element 28, the utility model overpower protection can stop output drive signal V
PWMTo power switch Q
1, to reach the overpower protection of power supply unit reality.
Cooperate Fig. 2, Fig. 7 is an embodiment circuit box schematic diagram of the utility model progression trigger element.Progression trigger element 28 includes: one keeps unit 284 is connected to overpower signal acquisition comparing unit 23 and oscillator 22, receives guard signal S
PTWith frequency signal CLK, in order to delay protection signal S
PTState, and export signal UP/DOWN about in the of.Counting unit 282 is connected to and keeps unit 284 and oscillator 22 about in the of one, and signal UP/DOWN and frequency signal CLK are to count computing about receiving.Enable (ON) of signal UP/DOWN makes that counting unit 282 can upwards be counted up and down about counting unit 282 bases up and down, and counting unit 282 can be counted downwards about making according to stop using (OFF) of signal UP/DOWN up and down, and when finishing, downward counting stops counting, the pick-off signal S of output high potential when upwards counting finishes
OFFWherein, frequency signal CLK is in order to decision drive signal V
PWMSwitching frequency with keep holding time of unit 284.
The unit 284 of keeping in the above-mentioned explanation is realized by two D flip- flops 2842 and 2844, when keeping the guard signal S that unit 284 receives electronegative potential
PTThe time.For the source and earthing pop-corn (ground bounce) that prevents to receive moment or switch the noise of surging (switching spike), keeping unit 284 needs the frequency signal CLK that cooperates oscillators 22 to produce, is used for delay protection signal S
PTState, and output high potential the UP/DOWN of signal up and down.
Cooperate Fig. 2, Fig. 8 is another embodiment circuit box schematic diagram of the utility model progression trigger element.In this embodiment, progression trigger element 28 is kept unit 284 by one and is connected to overpower signal acquisition comparing unit 23 and oscillator 22, to receive guard signal S
PTWith frequency signal CLK, in order to delay protection signal S
PTState, and export signal UP/DOWN about in the of.One switching switch 283 is connected to keeps unit 284, according to guard signal S
PTWhether enable, be controlled by the UP/DOWN of signal up and down that keeps unit 284 output, with output conducting or cut-off state.One variable capacitance 285 is connected to a charging current source 288 by diverter switch 283, obtains a charging current I according to the conducting state of diverter switch 283
CH, in order to export a charging voltage V
CHOne discharging current source 289 is connected in variable capacitance 285, provides a discharging current I according to the cut-off state of diverter switch 283
DCH, in order to variable capacitance 285 is discharged.One delay comparator 287 is connected to variable capacitance 285 and one the 4th minimum detectable signal V
T4, by comparing charging voltage V
CHWith the 4th minimum detectable signal V
T4, and in charging voltage V
CHGreater than the 4th minimum detectable signal V
T4The time produce pick-off signal S
OFF
The unit 284 of keeping in the above-mentioned explanation is realized by two D flip- flops 2842 and 2844, when keeping the guard signal S that unit 284 receives electronegative potential
PTThe time, for the noise that prevents to receive the source and earthing pop-corn of moment or switch surging, keep the frequency signal CLK that unit 284 needs to cooperate oscillator 22 generations, be used for postponing this guard signal S
PTState, and output high level the UP/DOWN of signal up and down.
When keep unit 284 receive overpower signal acquisition comparing unit 23 produce electronegative potentials guard signal S
PT, the UP/DOWN of signal up and down of output high potential causes diverter switch 283 to switch to conducting state.Variable capacitance 285 begins to charge by charging current source 288, the charging voltage V on variable capacitance 285
CHGreater than the 4th minimum detectable signal V
T4The time, delay comparator 287 will be exported the pick-off signal S of high potential
OFF
On the contrary, serve as power signal acquisition comparing unit 23 and stopped guard signal S
PTGeneration the time, diverter switch 283 will switch to cut-off state, the stored charging voltage V of variable capacitance 285 this moment
CHTo begin to discharge by discharging current source 289, and stop to export pick-off signal S
OFFHence one can see that, can change the duration of progression counting by the capacitance of adjusting variable capacitance 285.In addition, served as the utility model power protection Integration Design in the switching controller of power supply unit the time, variable capacitance 285 can be arranged at the outside of switching controller, or realizes by a fixed capacity that is arranged in the switching controller.
With reference to figure 2, latch lock unit 21 can realize that its frequency end is connected to progression trigger element 28 by a D flip-flop again, receives the pick-off signal S of high level
OFFLatch-up signal LATCH in order to output low level.Low level latch-up signal LATCH is connected to the D input of the D flip-flop (not indicating) among the drive signal generation unit 10a, makes that the D input of D flip-flop is an electronegative potential, and then makes drive signal generation unit 10a breech lock by drive signal V
PWM, to reach the purpose of latch protection.When power supply unit was subjected to latch protection, the electronic installation that its output coupled can't normal operation.
Cooperate Fig. 2, please refer to Fig. 9, be reset cell circuit box schematic diagram of the present utility model.The employed reset cell 24 of the utility model overpower protection is connected to latch lock unit 21, can reach the reset signal RST of output electronegative potential by dual mode, with replacement latch lock unit 21.Reset cell 24 can make power supply V according to the restarting power supply of power supply unit
DDRestart, export reset signal RST, in order to the latch lock unit 21 of resetting.This reset cell 24 also can produce in one setting-up time of back according to latch-up signal LATCH, and output reset signal RST is in order to this latch lock unit 21 of resetting.
This reset cell 24 comprises transistor 2401,2402 and 2403 divider resistances of being formed that are one another in series and connect, and can reflect lower supply voltage V in order to output
DDLow voltage signal V
LVBy inverter 2405, this low voltage signal V
LVThe conducting of oxide-semiconductor control transistors 2412 or end.In case can obtain to supply voltage V
DD, and transistor 2412 is cut-off state, 2411 pairs of replacement electric capacity 2413 of constant current source charge.Two NAND doors 2415 and 2416 are formed a SR buffer.NAND door 2415 and 2416 first input end are connected respectively to the output of NAND door 2416 and 2415.Second input of NAND door 2416 is connected to replacement electric capacity 2413.By inverter 2404, second input of NAND door 2415 is connected to the frequency signal CLK of oscillator 22.At the output of NAND door 2415, produce the reset signal RST of electronegative potential according to the electronegative potential on the replacement electric capacity 2413.After replacement electric capacity 2413 was charged to high potential, reset signal RST was for inactive, and generation frequency signal CLK.The pulse bandwidth of the current value decision reset signal RST of the capacitance of replacement electric capacity 2413 and constant current source 2411.
In sum; the utility model overpower protection not only provides power supply unit when different misoperation (overload, short circuit and feedback open circuit etc.) takes place; impel power supply unit to produce the protection action; more can count the duration that misoperation takes place, protect improperly when the big rated output power of special time domestic demand in order to avoid load end by progression.Therefore the utility model overpower protection circuit can provide power supply to supply complete protection scheme in fact.
The above, only be the detailed description and the accompanying drawing of the specific embodiment of one of the utility model the best, but feature of the present utility model is not limited thereto, be not in order to restriction the utility model, all scopes of the present utility model should be as the criterion with appending claims, all closing in the embodiment of the utility model spirit variation similar with it, all should be contained in the category of the present utility model, anyly be familiar with this operator in field of the present utility model, can think easily and variation or modify all can be encompassed in claims of the present utility model.
Claims (9)
1. an overpower protection is used in the power supply unit, obtains a sensing signal, it is characterized in that including:
One oscillator is exported a frequency signal;
One overpower signal acquisition comparing unit captures this sensing signal and it and a minimum detectable signal is compared computing, to export a guard signal;
One progression trigger element is connected in this overpower signal acquisition comparing unit and this oscillator, receives this guard signal and this frequency signal, exports a pick-off signal;
One latch lock unit is connected in this progression trigger element, receives this pick-off signal, exports a latch-up signal;
One drive signal generation unit is connected in this latch lock unit and this oscillator, receive this frequency signal with in order to stop to export a drive signal this latch-up signal to a power switch; And
One drive signal control unit, be connected in this drive signal generation unit, receive this sensing signal and one second minimum detectable signal, when this sensing signal rises to this second minimum detectable signal, the drive signal control unit is exported a clear signal to this drive signal generation unit, to arrive this power switch by this drive signal;
Wherein, this guard signal is counted in this progression trigger element progression, wait the counting of this guard signal to arrive a default value after, this latch lock unit is controlled this drive signal generation unit, with breech lock by this drive signal to this power switch.
2. overpower protection as claimed in claim 1; it is characterized in that further including a reset cell and be connected in this latch lock unit and this oscillator; receive this frequency signal and this latch-up signal; and after receiving this latch-up signal, in the setting-up time, export a reset signal in order to this latch lock unit of resetting and arrive this latch lock unit.
3. overpower protection as claimed in claim 2; it is characterized in that this reset cell further connects a supply voltage; restart according to this power supply unit and to receive a low voltage signal behind the power supply, with export one in order to the reset signal of this latch lock unit of resetting to this latch lock unit.
4. overpower protection as claimed in claim 1 is characterized in that this overpower signal acquisition comparing unit is a current comparator, and comparison operation one first minimum detectable signal and a current sensing signal are to export one first guard signal to this progression trigger element.
5. overpower protection as claimed in claim 1; it is characterized in that this overpower signal acquisition comparing unit is a voltage comparator; comparison operation 1 the 3rd minimum detectable signal and a Voltage Feedback sensing signal are to export one second guard signal to this progression trigger element.
6. overpower protection as claimed in claim 1 is characterized in that this overpower signal acquisition comparing unit includes:
One current comparator, comparison operation one first minimum detectable signal and a current sensing signal are to export one first guard signal;
One voltage comparator, comparison operation 1 the 3rd minimum detectable signal and a Voltage Feedback sensing signal are to export one second guard signal; And
One linkage unit is connected in this current comparator, this voltage comparator and this progression trigger element, and this first guard signal and this second guard signal are sent to this progression trigger element.
7. overpower protection as claimed in claim 1 is characterized in that this progression trigger element includes:
One keeps the unit, is connected to this overpower signal acquisition comparing unit and this oscillator, receives this guard signal and this frequency signal, postponing the state of this guard signal, and exports signal about in the of; And
Counting unit about in the of one is connected to this and keeps unit and this oscillator, receives up and down signal and this frequency signal counting computing, and stop counting when downward counting finishes, and exports this pick-off signal when counting end upwards.
8. overpower protection as claimed in claim 7 is characterized in that this up and down counting unit, according to this up and down signal enable the counting that make progress, and according to this stopping using of signal and downward counting the up and down.
9. overpower protection as claimed in claim 1 is characterized in that this progression trigger element includes:
One keeps the unit, is connected to this overpower signal acquisition comparing unit and this oscillator, receives this guard signal and this frequency signal, postponing the state of this guard signal, and exports signal about in the of;
Whether one switches switch, is connected to this and keeps the unit, receives signal up and down, and enable according to this guard signal and to export conducting or cut-off state;
One variable capacitance, be connected to a charging current source by this diverter switch, conducting state according to this diverter switch obtains a charging current, to export a charging voltage, this variable capacitance also is connected to a discharging current source by this diverter switch, this discharging current source provides a discharging current according to the cut-off state of this diverter switch, so that this variable capacitance is discharged; And a delay comparator, be connected to this variable capacitance and one the 4th minimum detectable signal, by relatively this charging voltage and the 4th minimum detectable signal, and produce this pick-off signal during greater than the 4th minimum detectable signal in this charging voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2005200045598U CN2796208Y (en) | 2005-04-08 | 2005-04-08 | Over-power protector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2005200045598U CN2796208Y (en) | 2005-04-08 | 2005-04-08 | Over-power protector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2796208Y true CN2796208Y (en) | 2006-07-12 |
Family
ID=36813955
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2005200045598U Expired - Fee Related CN2796208Y (en) | 2005-04-08 | 2005-04-08 | Over-power protector |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2796208Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102820842A (en) * | 2011-06-10 | 2012-12-12 | 尼克森微电子股份有限公司 | Motor driving device and lockout protection and standby control circuit for same |
| CN105529683A (en) * | 2016-02-17 | 2016-04-27 | 深圳市赢新光电发展有限公司 | Secondary overpower protection circuit and switching power supply |
| CN111900783A (en) * | 2019-05-05 | 2020-11-06 | 宏碁股份有限公司 | Over-power protection circuit, charger and over-power protection method |
-
2005
- 2005-04-08 CN CNU2005200045598U patent/CN2796208Y/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102820842A (en) * | 2011-06-10 | 2012-12-12 | 尼克森微电子股份有限公司 | Motor driving device and lockout protection and standby control circuit for same |
| CN102820842B (en) * | 2011-06-10 | 2015-01-14 | 尼克森微电子股份有限公司 | Motor driving device and lockout protection and standby control circuit for same |
| CN105529683A (en) * | 2016-02-17 | 2016-04-27 | 深圳市赢新光电发展有限公司 | Secondary overpower protection circuit and switching power supply |
| CN105529683B (en) * | 2016-02-17 | 2018-01-02 | 深圳茂硕电子科技有限公司 | A kind of secondary overpower-protection circuit and Switching Power Supply |
| CN111900783A (en) * | 2019-05-05 | 2020-11-06 | 宏碁股份有限公司 | Over-power protection circuit, charger and over-power protection method |
| CN111900783B (en) * | 2019-05-05 | 2022-05-03 | 宏碁股份有限公司 | Over-power protection circuit, charger and over-power protection method |
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| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20060712 |