CN104078938B - Detect the method and circuit of short circuit in asynchronous DC boost converter - Google Patents
Detect the method and circuit of short circuit in asynchronous DC boost converter Download PDFInfo
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Abstract
Using the simple wiring of the earth terminal on PCB, in asynchronous DC boost converter, easy, cost-effective and efficient short-circuit protection is obtained, wherein when a short circuit occurs, voltage sensor controller optionally makes input power and load isolation.The controller just can detect short circuit using circuit and the circuit under overvoltage protection under voltage blocking protection without the need for additional element.The offset voltage for pre-setting is increased to into sensing output voltage, produce reference voltage, reference voltage is compared with sensing input voltage, when reference voltage is less than sensing input voltage, produce the output signal with high state, when output signal is in high state, the source electrode of power supply is optionally made to fail.
Description
Technical field
The present invention relates to detect short-circuit conditions in asynchronous DC-To-DC boost converter, and prevent from burning out related elements.
Background technology
Boost converter is generally used for providing stepped voltage for drive connection load.Due to diode or Schottky diode
Deng asynchronous switch unlike other synchro switches such as BJT, MOSFET, IGBT, drive circuit is needed, therefore most of steppings are straight
Stream-direct current transducer all adopts asynchronous switch as switch.The structure of asynchronous DC-To-DC boost converter do not allow cut off from
Current path of the input power to output loading.If during normal work, the voltage of input power is higher than output voltage, then just
Short circuit can be produced, huge electric current flow to output from input, and inductance and asynchronous switch constitute DC-To-DC boost converter electricity
Road.If circuit is not turned off, then short circuit will burn out inductor or asynchronous switch.Accordingly, it would be desirable to the method for detecting short circuit,
Short-circuit signal should be delivered to input power controller or insulated switch driver, to cut off circuit.
Asynchronous DC-To-DC boost converter contains a controller, in addition to detection short circuit, goes back control circuit element
Operation, protection circuit element do not affected by high short circuit current.Protection controller usually contains a comparator, will flow through different
The sensing voltage that the electric current of step DC-To-DC boost converter is produced, compared with short-circuit detecting threshold voltage reference value.Relatively
Device compares both voltage signals, so as to provide a kind of signal for failure mode, for cutting off the input power in load.It is this
Traditional converter includes a current sense circuit, and in predefined structure, the circuit usually contains resistor and electric capacity
Device, for determining the electric current for flowing through load.When in asynchronous DC-To-DC boost converter or when being short-circuited in load circuit,
Have very big electric current and system earth end is flow to by default resistor, so as to produce pressure reduction.Then, pressure reduction is used as comparator
Input, compared with short-circuit detecting threshold voltage reference value, input power is disconnected with asynchronous DC-To-DC boost converter
Connection.Therefore, controller can be when being short-circuited, it is ensured that input power disconnects.
The work of controller noted above is based on the short circuit current for being transferred to comparator input terminal.For the short circuit of sense current
Resistor needs an extra filter circuit in parallel, to eliminate noise unnecessary in circuit.Short-circuit resistor must have
One optimum value, to guarantee accuracy, while avoiding very big power attenuation enough, this can increase the cost of controller circuitry.
Short-circuit resistor must be accurately calibrated, short circuit current could be sensed, it is very expensive in circuit that this causes it to use.And, by
When in converter normal work, short-circuit resistor federation power consumption, therefore the power attenuation that short-circuit resistor causes can not
Ignore.
Therefore, it is necessary to being necessary for asynchronous DC-To-DC boost converter develops a kind of more preferable, efficient protection control
Device, can protect asynchronous DC-To-DC boost converter and load not to be burned with the big short circuit current of accurate detection.
The content of the invention
According to one embodiment of the present of invention, it is proposed that a kind of voltage for asynchronous DC-To-DC boost converter is passed
Sense controller, the controller are used to optionally make input power and load isolation, and the controller includes：
One circuit, with a first node for being connected to input power, and a second section for being connected to load
Point；
First divider contains first pair of resistor, for being connected between first node and earth terminal, is additionally operable to produce
Sensing input voltage；
Second divider contains second pair of resistor, for being connected between Section Point and earth terminal, is additionally operable to produce
Second sensing output voltage；
Offset voltage generator is used to receive sensing input voltage and sensing output voltage, determines sensing input voltage and biography
Offset voltage between sense output voltage；
Reference voltage generator produces reference voltage for offset voltage is increased to sensing output voltage；
Comparator is used to compare sensing input voltage and reference voltage, produces output signal, when reference voltage is less than sensing
During input voltage, the output signal with high state is produced, when reference voltage is more than sensing input voltage, produced with low shape
The output signal of state；And
Failure mode is used to receive output signal, produces disablement signal, when output signal is high state, makes input power
Drain selection ground failure.
When having very big difference between the output voltage and input voltage of converter, proposed in this explanation is optional
Embodiment also includes the 3rd divider, is merely provided for overvoltage protection, wherein the first and second divider provide short circuit
Protection.
According to a preferred embodiment, the value of first pair of resistor and second pair of resistor is selected, first pair of resistor is made
Ratio it is equal with the ratio of second pair of resistor.According to the input offset voltage of comparator, compensation can be easily determined very much
Voltage, the voltage admissible short circuit current energy level of correspondence and at the Section Point output voltage decreasing value.
In general, failure mode contains a delay circuit, for before disablement signal is produced, introducing one section of determination
Time delay.
According to the present invention, controller includes at least one of independent component, integrated circuit and hydrid integrated circuit.
Controller noted above is generally used for LED backlight system and electronics guard system.
According to the present invention, it is proposed that a kind of side for making asynchronous DC-To-DC boost converter optionally with load isolation
Method, the method are comprised the following steps：
Input power is connected to into first node；
Connect loads to Section Point；
In normal operation, the input voltage from first node determines admissible output voltage drop at Section Point,
The admissible short circuit current of voltage correspondence；
Produce the sensing input voltage of correspondence input power；
At Section Point, the sensing output voltage of correspondence output voltage is produced；
Receive sensing input voltage and sensing output voltage；
According to admissible pressure reduction between input and output, the benefit between sensing input voltage and sensing output voltage is determined
Repay voltage, including the input offset voltage of comparator；
Increase offset voltage and sensing output voltage, produce reference voltage；
Relatively sensing input voltage and reference voltage, when output voltage is less than sensing input voltage, produce with high shape
The output signal of state, when reference output voltage is more than sensing input voltage, produces the output signal with low state；
Receive output signal；And
When output signal is in high state, input power is optionally made to fail.
In general, as described above, before the step of producing sensing input voltage and produce sensing output voltage, will also enter
Row following steps：
Choose first pair of resistor for constituting the first divider, and second pair of resistor of the second divider of composition, choosing
The value of first pair of resistor and second pair of resistor is selected, makes the ratio of first pair of resistor be equal to the ratio of second pair of resistor,
First pair of resistor is used to arrange the input voltage under voltage blocking protection, and as the first sensing electricity of comparator input terminal
Pressure, second pair of resistor are used to arrange the threshold voltage of overvoltage protection, and as the second sensing electricity of comparator input terminal
Pressure；
The first divider between connection first node and earth terminal；And
The second divider between connection Section Point and earth terminal.
In general, as described above, following steps are also performed to before the step of comparing：
Second input voltage is connected to into the non-steering end of comparator；
Reference voltage is connected to into the steering end of comparator；And
The input offset voltage of comparator is increased in offset voltage.
In general, as described above, being also performed to provide predefined before the step of making input power selectively fail
Time delay.
Some targets of the present invention are intended to improve one or more problems of original technology, or provide at following effective
Alternative：
An object of the invention is intended to detect short circuit in asynchronous DC-DC boost converter circuit.
Another target of the present invention is intended to protect the element of asynchronous DC-To-DC boost converter will not when being short-circuited
It is burned.
Another target of the present invention is intended to reduce in asynchronous DC-To-DC boost converter the tradition electricity used by short-circuit protection
The power attenuation occurred in road.
Another target of the present invention is directed to a kind of cost-effective controller, in asynchronous DC-DC voltage boosting
Each element is protected when being short-circuited in converter.
Another target of the present invention is directed to a kind of controller of simplicity, for changing in asynchronous DC-DC voltage boosting
Each element is protected when being short-circuited in device.
Another target of the present invention is directed to a kind of efficient controller, to turn in asynchronous DC-DC voltage boosting
Each element is protected when being short-circuited in parallel operation.
Another target of the present invention is directed to a kind of controller, to send out in asynchronous DC-To-DC boost converter
Each element is protected during raw short circuit, the controller is made up of relatively small number of element.
Description of the drawings
Fig. 1 represents the traditional controller relevant with asynchronous DC-To-DC boost converter, for PWM brightness adjustment controls
LED backlight system, carry out traditional short-circuit protection including the method sensed using negative current；
Fig. 2 represents one embodiment of the present of invention relevant with asynchronous DC-To-DC boost converter, for PWM
The LED backlight system of brightness adjustment control；
Fig. 3 is represented according to an alternative embodiment of the invention, a control relevant with asynchronous DC-To-DC boost converter
Device processed, for the LED backlight system with PWM brightness adjustment controls；
Corresponding parameter/mark represents the corresponding part of each schematic diagram of accompanying drawing.
Specific embodiment
In the present invention, " load " used refers to, but is not limited to low power load, including light emitting diode（LED）, lamp
Bubble, background light etc..
In the present invention, " node " used is referred to, but is not limited at least two elements of a tie point or circuit node
Reallocation point.
" short circuit " or " short circuit " used by the present invention is referred to, but is not limited to node is connected electrically at another node
Phenomenon.
In the present invention, " comparator " used refers to comparator and operational amplifier.
In the present invention, " below voltage blocking energy level " used is referred to, but is not limited to predefined operating voltage energy level.
Other inventions being additional in this area defined above.
Term used herein is merely to illustrate specific embodiment, is not used to limitation.Unless stated otherwise, otherwise in text
Singulative " one " used, " one kind " and " that " can also include plural form.Term " including ", "comprising" and " tool
Have " be included in, therefore specific feature, entirety, operation, composition and/or part to be particularly pointed out, but be not excluded for addition
One or more are levied, entirety, operation, composition, part and/or component.Unless specifically stated otherwise has performance requirement, otherwise in text
Described method and step, flow process and operation are not required for the performance requirement.
Be referred to as when an element or layer " ... on ", " being installed to ", " being connected to " or " being coupled to " another element
Or when on layer, refer to ... and go up, install, being connected or coupled on other elements or layer, or exist intermediary element or
Layer.In contrast, when an element is referred to as " on directly existing ... ", " to be mounted directly to ", " being directly connected to " or " direct coupling
Close " on another element or layer when, there is no other intermediary elements or layer.Other words Ying Yiyi of relation between description element
Plant similar mode to explain（For example, " between " and " being close to ", " near " and " close to " etc.）.Term used herein " and/
Or " including one or more correlation name purposes arbitrarily and integer combinations.
Although word first, second, third, etc. used herein represent each element, part, region, layer and/or part,
But these elements, part, region, layer and/or part are not limited only to these words.Word used be only used for distinguish element, zero
Part, region, layer and/or part and another region, layer or part.Unless specifically stated, " first " used herein,
Words such as " second " and other numbers are not necessarily referring to a sequence or order.Therefore, on the premise of being intended to without departing from embodiment, under
The first element, part, region, layer or part in text is it is also assumed that be the second element, part, region, layer or part.
Fig. 1 represents a kind of traditional controller relevant with asynchronous DC-To-DC boost converter, referring in particular to integrated
Circuit IC chip, for the LED backlight system with PWM brightness adjustment controls, PWM brightness adjustment controls are included using negative current method for sensing
Carry out traditional short-circuit protection.As illustrated, asynchronous DC-To-DC boost converter 100 includes that a controller 106 is connected to
Current sense circuit 108.By resistor R1 and R2 constitute divider, first node Vin locate sensing input voltage, be input into
Voltage is loaded on controller 106 at lead UVLO.Lead UVLO is protected for providing voltage blocking along resistor R1 and R2
Shield.The divider consisted of resistor R3 and R4, senses output voltage at Section Point Vout, and input voltage is in lead
It is loaded at OVP on controller 106.Value according to selected by resistor R3 and R4, the sensing voltage at lead OVP provided electricity
Pressure protection.From first node Vin to the electric current of Section Point Vout, inductor L1 and asynchronous switch are flowed through（Typically diode
D1）, also flow into load 112（Typically series of LED）.Current sense circuit 108 includes one with resistor Rc and capacitor
Short-circuit resistor Rsht Cc in parallel, current sense circuit 108 are also connected to the lead NCS of controller 106（Negative current is sensed）.
The protection circuit of controller 106 includes a comparator 110, compares the sensing from electric current I_VIN in current sense circuit 108
Pressure reduction and short-circuit detecting threshold reference voltage（-0.2V）, and produce output signal Vcom, it is further provided failure mode, leads to
Cross disablement signal（104）Make input power fail, in order to stable, disablement signal 104 is provided by delay circuit 102.Control
Device processed 106 also includes a pulse width modulator being connected on lead DPWM, is used for LED current in LED backlight driver part
Brightness adjustment control.By the current set resistor Rset being connected on the lead ISET of controller 106, modulation flows through load 112
Electric current.Switch M2 and lead DPWM opens PWM brightness adjustment controls according to external signal.In FIG, there are two kinds of earth terminals, system
Earth terminal 113 is connected to all of earth terminal of complication system, be connected to window frame window frame earth terminal 114 surround LED module and
The earth terminal of controller IC 106.Two earth terminals are coupled by current sense circuit 108（113、114）.When load 112 or LED
When being short-circuited in any point of circuit, short circuit current I_VIN can by inductor L1, asynchronous switch D1, short circuit LED112,
Dimming control switch M2 and current sense circuit 108, flow to system earth end 113 from input power Vin.
When asynchronous DC-To-DC boost converter 100 is normal to be run, electric current by inductor L1, asynchronous switch D1,
LED line road 112, dimming control switch M2, LED current arrange resistor Rset and current sense circuit 108, from input power
Vin flow to system earth end 113.When IC earth terminals are short-circuited, by the output end of asynchronous DC-To-DC boost converter
Or any point on LED line road 112, have very high electric current I_VIN and flow through load 112 and inductor L1 and diode D1 etc.
Other components, flow to IC earth terminals, subsequently as illustrated, the system that electric current I_VIN is flow in current sense circuit 108 connects
Ground terminal, by short-circuit resistor Rsht, produces pressure reduction Vsht.Pressure reduction Vsht makes the voltage level at lead NCS be down to IC ground connection
Under end, its amplitude is proportional to pressure reduction Vsht.When the amplitude of pressure reduction Vsht increases to more than 0.2V, the inversion of comparator 110
The NCS lead voltages of end place loading make short-circuit detecting threshold reference voltage reduce than the non-inversion end of comparator 110-
0.2V, output signal Vcom are raised, so that input power failure.In other words, when pressure reduction Vsht is more than 0.2V, comparator
110 output end Vcom is raised, and Vsht has below equation：
Therefore, Vcom=" height " refers to DIS=" height ", and disablement signal 104 makes input power by controller 106 and load
112 disconnect.Disablement signal 104 directly makes input power fail, or between input power and DC-to-dc converter
A part of the insulated switch as deactivation system.
In order to avoid producing noise during negative current sensing NCS in current sense circuit 108, as low pass filter
Resistor Rc and capacitor Cc it is in parallel with short-circuit resistor Rsht.As the value of short-circuit resistor Rsht must be sufficiently small,
It is avoided that and produces very high power attenuation, and it is exactly accurate, short-circuit resistor Rsht is sensed with the low-lying level of Vsht, therefore
Short-circuit resistor Rsht is costly.Short-circuit resistor Rsht in normal operation, damage by federation's power consumption, the power caused by it
Consumption can not be ignored, so will be increased using converter holistic cost made by negative current as known in the art sensing NCS modes
Plus.
However, due to power attenuation it is particularly critical in low power system, therefore low-voltage load in the case of, for example
LED backlight system, LED photosystem and its similar system, need a kind of efficient system, it is possible to reduce power attenuation, protection
Load is not affected by high short circuit current, and will not reduce efficiency.
Fig. 2 is represented according to one embodiment of the present of invention, a kind of control relevant with asynchronous DC-To-DC boost converter
Device.With reference to IC chip, described controller is particularly suited for the LED backlight system with PWM brightness adjustment controls.So
And, using the independent component of hydrid integrated circuit, configure circuit of the present invention and be considered as within the scope of the invention.Such as
Shown in figure, boost converter 200 includes a controller 206, for the time detecting of short circuit, and makes power supply with load 210（It is logical
It is often LED line road）Insulation.By the resistor Rset being connected at lead ISET, modulation flows through the electric current of load 210.Control
Device 206 also includes a pulse width modulator, is controlled by lead DPWM, in LED-backlit drives is used for LED brightness adjustment controls.Switch
M2 and lead DPWM triggers PWM brightness adjustment controls according to external signal.
First divider provides sensing input voltage, and the first divider includes resistor R1 and R2, by sensing first
The input power received at node Vin, is connected to lead UVLO.Second divider provides sensing output voltage, the second divider
Including resistor R3 and R4, by sensing the voltage at Section Point Vout, lead OVP is connected to.Controller 206 includes comparing
Device 208, for comparing sensing input voltage and sensing output voltage.For the ease of calculating, choosing resistance value respectively includes resistance
It is right（R1 and R2）And resistance pair（R3 and R4）, make their ratio equal.First resistor pair（R1 and R2）Ratio as electricity
Press off the threshold voltage under lock UVLO protections, and the sensing input voltage of comparator 208, second resistance pair（R3 and R4）Ratio
It is worth as the threshold voltage under overvoltage protection OVP, and the sensing output voltage of comparator 208.Comparator 208 is by lead
Sensing voltage at OVP and UVLO is constituted, and produces output signal Vcom.Output signal Vcom of comparator 208 is drawn in DIS
At line, by delay circuit 202, transmit to failure mode, so that input power failure.
When input power is loaded on asynchronous DC-To-DC boost converter, minimum output electricity at Section Point Vout
Pressure can be represented with following formula：
Forward voltages of the wherein VF for diode D1 asynchronous switches.When asynchronous DC-To-DC boost converter is unavailable or
When not working, above formula can use.In normal operation, as the output of stepping DC-to-dc converter is always not less than input, because
This Vout is always above Vin.When any point on node Vout or LED line road 210 is short-circuited, very high short circuit is had
Electric current I_VIN flows through load 210 and other elements, and such as inductor L1, diode D1, short circuit LED line road 210 and PWM are adjusted
Photoswitch M2.In order to avoid further injecting into this high short circuit current I_VIN, by disablement signal 204 make input power with it is different
Step DC-To-DC boost converter 200 is disconnected.In order to produce the disablement signal for making load 210 and input power insulation, this
The described controller of invention using when being short-circuited in asynchronous DC-To-DC boost converter 200, at Section Point Vout
Voltage level drops suddenly to the principle of below the voltage level at first node Vin and makes.According to offset voltage Voff
The input offset voltage of comparator 208, provides sensing output voltage and sensing input voltage for comparator, in Section Point Vout
The voltage drop value that place allows, and the voltage of the short circuit current energy level of correspondence permission.Sensing input voltage and sensing output voltage it
Between pressure reduction pre-set by offset voltage generator, for providing stable for comparator 208 input
Short-circuit protection.Reference voltage generator provides sensing output voltage（At OVP leads）With the sum of offset voltage Voff, as than
The reference voltage at end is turned to compared with device 208.Comparator 208 compares the voltage signal of its input, when reference voltage less than sensing it is defeated
When entering voltage, output signal Vcom with high state is produced, when reference voltage is more than sensing input voltage, produced with low
Output signal Vcom of state.
When output signal Vcom correspondence high state, voltage at the forward voltage VF and Section Point Vout of asynchronous switch D1
And less than the voltage at first node Vin.Therefore, the voltage at lead UVLO is higher than at offset voltage Voff and lead OVP
The sum of voltage, then comparator output Vcom enter high state, can be represented with following formula, wherein R1=R3, R2=R4：
Output signal Vcom of comparator 208 is used for failure mode, and failure mode generally includes a delay circuit 202,
Before disablement signal 204 makes input power fail, there is provided precalculated accurate delay value.By at least introducing anti-spike
A kind of method in the methods such as impulse circuit, filter circuit, delay circuit, mitigates the problem related to noise, makes delay circuit
102 provide stable operation.
As shown in Fig. 2 having had due to UVLO and OVP to different from resistance extra in the traditional circuit shown in Fig. 1
Function is also used for short-circuit protection, therefore system of the present invention does not need extra element.Additionally, by biography as shown in Figure 1
The negative current sensing circuit of the guard method of system, not unnecessary power attenuation.Due to only one of which common ground end, therefore
The more excellent performance of the ground path of printing board PCB, and it is more convenient.
Fig. 3 is represented according to an alternative embodiment of the invention, a kind of control relevant with asynchronous DC-To-DC boost converter
Device processed.The present embodiment is particularly suited for PWM brightness adjustment controls（Particularly there is high Vout/Vin ratios）LED backlight system in
Asynchronous DC-To-DC boost converter short-circuit protection.Controller noted above and integrated circuit（IC）Chip is relevant.However, sharp
With the independent component of hydrid integrated circuit, configure circuit of the present invention and be considered as within the scope of the invention.As schemed
Show, asynchronous DC-To-DC boost converter 300 includes a controller 306, by the conversion for making to connect at Section Point Vout
Device 300 or load 310, do not receive high short with the input power insulation being connected at first node Vin, protection element and load 310
The impact of road electric current I_VIN.Controller 306 includes a comparator 308, compares sensing input voltage and sensing output voltage.
Sensing input voltage is provided by the first divider that resistor R1 and R2 are constituted, resistor R1 and R2 are connected to lead UVLO.By
Second divider of resistor R5 and R6 composition provides sensing output voltage, and resistor R5 and R6 are connected to lead VOSEN.In order to
It is easy to calculate, chooses resistor pair（R1 and R2）And resistor pair（R5 and R6）The resistor values of composition, make their ratio
It is equal.First resistor device pair（R1 and R2）Ratio as the threshold voltage under voltage blocking UVLO protections, and comparator 308
Sensing input voltage, second resistance device pair（R5 and R6）Ratio as comparator 308 sensing output voltage.By resistor
3rd divider of R3 and R4 compositions is connected on lead OVP, and the resistance value of lead OVP is protected based on the overvoltage for pre-setting
Shield threshold value, protects for output over-voltage.Comparator 308 is by the biography at offset voltage Voff for pre-setting and lead VOSEN
The sum of electrification pressure, compared with the sensing voltage at lead UVLO, and produces output signal Vcom.By being connected to lead
Resistor Rset at ISET, modulation flow through the electric current of load 310.Switch M2 and lead DPWM activates PWM according to external signal
Brightness adjustment control.
When the ratio for sensing output voltage and sensing input voltage is very high, divider on lead OVP is connected to not
Asynchronous DC-To-DC boost converter as shown in Fig. 2, the double of output voltage are sensed for overvoltage protection and generation
Weight function.In this case, due to the load according to required operating voltage and series connection（For example LED load or be used for backlight
Lamp load of system etc.）Electric current needed for quantity, and load 310, the voltage level at Section Point Vout is variable, therefore nothing
The threshold value of method amendment overvoltage protection.By resistance pair（R3 and R4）The value of the resistance for being constituted, is not equal to and resistance pair（R1 and
R2）The value of the resistance for being constituted；It is special to choose resistance pair（R3 and R4）Value, for overvoltage protection.Therefore, work as Vout/Vin
Value it is very high when, the 3rd divider being connected on lead OVP（R3 and R4）Overvoltage protection is only used for, lead is connected to
The second divider on VOSEN（R5 and R6）It is only used for producing sensing output voltage.
When a short circuit occurs, the voltage level at Section Point Vout is rapidly decreased to the voltage level at first node Vin
Hereinafter, have very high short circuit current I_VIN and flow through the other elements such as load 310, inductor L1 and diode D1, and
The load of the short circuits such as LED line road.The voltage drop values that input offset voltage, Section Point Vout according to comparator 308 is allowed
And correspondence allows the voltage of short circuit current current levels, sensing input voltage and sensing output voltage to be loaded onto with compensation electricity
On the comparator of pressure Voff.By offset voltage generator, pre-set between sensing input voltage and sensing output voltage
Pressure reduction, is loaded onto on one of input of comparator 208, for stable short-circuit protection.Reference voltage generator is provided
Sensing output voltage（At VOSEN leads）With offset voltage Voff and as the reference voltage, be loaded onto comparator 308 turn
Xiang Duan.Comparator 308 compares the voltage signal of its input, when reference voltage is less than sensing input voltage, produces with height
Output signal Vcom of state, when reference voltage is more than sensing input voltage, produces output signal Vcom with low state.
When lead DIS has disablement signal, offset voltage can be represented with following formula：
And
Output signal Vcom of comparator 308 has failure mode, is generally used for delay circuit 302, input power from
Before converter fails or disablement signal 304 makes loading failure, delay circuit provides precalculated accurate delay value.
Therefore, it is used for without the need for known additional element in original technology according to the controller shown in Fig. 2 of the present invention and Fig. 3
Detection short-circuit conditions, generation make the signal of input power and load isolation, so as to reduce the power attenuation of system, reduce into
This, improves the efficiency of system.
In circuit shown in Fig. 2 of the present invention and Fig. 3, the ground path on IC is simpler, a public earth terminal ratio
Need detached system earth end to compare with window frame voltage in traditional circuit shown in Fig. 1, improve performance and more save
Cost.The part purpose of the present invention is intended to improve one or more problems of original technology, or at least proposes a kind of effective
Alternative：
One aspect of the present invention is intended to detect the short circuit in asynchronous DC-DC boost converter circuit.
Another aspect of the present invention is intended to protect the element in asynchronous DC-DC boost converter circuit, it is to avoid sending out
It is burned during raw short circuit.
Another aspect of the present invention is intended to reduce the power attenuation in traditional circuit, turns for asynchronous DC-DC voltage boosting
Short-circuit protection in parallel operation.
Another aspect of the present invention is directed to a kind of cost-effective controller, in asynchronous DC-DC voltage boosting
Each element is protected during short circuit in converter.
Another aspect of the present invention is directed to a kind of simple controller, without the need for the additional circuit of short-circuit detecting, is used for
Each element is protected during short circuit in asynchronous DC-To-DC boost converter, the controller contains relatively small number of parts.
Another aspect of the present invention is directed to a kind of efficient controller, for changing in asynchronous DC-DC voltage boosting
Each element is protected during short circuit in device.
Another aspect of the present invention be directed to it is a kind of without the need in PCB layouts divide earth terminal controller, for
Each element is protected during short circuit in asynchronous DC-To-DC boost converter.
Controller as above is generally used for LED backlight system and lighting system.
Technique advance and economic implications produced by the present invention：
The advance of technique of the present invention includes realizing：
A kind of controller that short circuit is detected in asynchronous DC-DC boost converter circuit；
The control that a kind of parts for protecting asynchronous DC-DC boost converter circuit will not be burned when being short-circuited
Device processed；
A kind of controller for reducing power attenuation in traditional circuit, in asynchronous DC-To-DC boost converter
Short-circuit protection；
A kind of cost-effective controller, for each unit is protected when asynchronous DC-To-DC boost converter is short-circuited
Part；
A kind of easy controller that short circuit is detected without the need for additional circuit, for sending out in asynchronous DC-To-DC boost converter
Each element is protected during raw short circuit, the controller contains relatively small number of element；
A kind of efficient controller, protects each element when being short-circuited in asynchronous DC-To-DC boost converter；And
A kind of simple layout with single earth terminal, without the need for dividing earth terminal in printing board PCB, just can be asynchronous
Short-circuit protection is provided in the controller of DC-To-DC boost converter.
Use " at least " or " at least one " is referred to using one or more elements or composition or quantity, and the present invention's
Realize in embodiment that target needed for one or more is consistent with the usage of result.
Any file, regulation, material, device, article in this explanation etc. are only used for providing explanation for the present invention.Due to this
Any one in a little materials or all material presence before the priority date of the application phase, therefore do not allow their structures
Into a part for original technology, or as the common sense of relevant art.
When specifying the scope of certain value, it is intended that in the range of the maximum and minimum value of the value float respectively up and down and 10% still fall within this
The scope of invention.
The numerical value of different physical, size or quantity is only approximate number, unless specifically stated, be considered as higher than/it is low
Parameter, size or quantity in the numerical value belongs to the scope of the present invention.
The described above of exemplary embodiments by the general principle of complete illustrated embodiments, using existing knowledge, can be not
On the basis of running counter to general principle, various applications are easily corrected and/or be used for, therefore these amendments and adjustment are considered as belonging to institute
State in the range of the equivalent of embodiment.It should be understood that the wording and term in text is only used for illustrating, limit is not used to
System.Therefore, those skilled in the art is it should be appreciated that the above-described embodiment according to preferred embodiment can be in enforcement of the present invention
In the intention and scope of example, it is capable of achieving by amendment.
Claims (11)
1. a kind of voltage sensor controller for asynchronous DC-To-DC boost converter, described controller are used to produce letter
Number, optionally make input power and load isolation, it is characterised in that described controller includes：
One circuit with the first node being connected on input power and the Section Point being connected in load；
One the first divider, including first pair of resistor, for being connected between described first node and earth terminal, also use
In generation sensing input voltage；
One the second divider, including second pair of resistor, for being connected between described Section Point and earth terminal, also use
Output voltage is sensed in producing；
One offset voltage generator, for receiving described sensing input voltage and sensing output voltage, it is determined that described biography
Offset voltage between sense input voltage and described sensing output voltage；
One reference voltage generator, for described offset voltage is increased to described sensing output voltage, and produces ginseng
Examine voltage；
One comparator, for relatively more described sensing input voltage and described reference voltage, and when described reference electricity
When pressure is less than described sensing input voltage, the output signal with high state is produced, when described reference voltage is more than described
Sensing input voltage when, produce with low state output signal；And
Failure mode, for receiving the output signal described in described comparator, produces disablement signal, when described output is believed
Number in described high state when, make input power fail.
2. the voltage sensor controller of asynchronous DC-To-DC boost converter is used for as claimed in claim 1, and its feature exists
In also including the 3rd divider, which determines intrinsic standoff ratio according to the overvoltage protection threshold value for pre-setting.
3. the voltage sensor controller of asynchronous DC-To-DC boost converter is used for as claimed in claim 1, and its feature exists
In wherein described offset voltage includes the input offset voltage of described comparator, the admissible circuital current of voltage correspondence
Energy level and can allow at described Section Point reduce output voltage values.
4. the voltage sensor controller of asynchronous DC-To-DC boost converter is used for as claimed in claim 1, and its feature exists
In described disablement signal includes a delay circuit, for, before described disablement signal is produced, introducing one section and setting in advance
The time delay put.
5. the voltage sensor controller of asynchronous DC-To-DC boost converter is used for as claimed in claim 1, and its feature exists
In described controller includes at least one of independent component and integrated circuit.
6. a kind of LED backlight system, it is characterised in that including the controller described in claim 1.
7. a kind of lighting system, it is characterised in that including the controller described in claim 1.
8. a kind of method of input power for optionally making asynchronous DC-To-DC boost converter and load isolation, its feature
It is that the method is comprised the following steps：
Input power is connected to into first node；
Connect loads to Section Point；
In normal operation, from the beginning of the input voltage at first node, the output that can allow to reduce is limited at Section Point
Voltage, admissible voltage correspondence short circuit current；
According to input power, sensing input voltage is produced；
According to the output voltage at Section Point, sensing output voltage is produced；
Receive described sensing input voltage and sensing output voltage；
According to allowing voltage drop and allow voltage, it is determined that the compensation between described sensing input voltage and sensing output voltage
Voltage；
Increase described offset voltage and described sensing output voltage, produce reference voltage；
Relatively more described sensing input voltage and described reference voltage, when described reference voltage is less than described sensing input
During voltage, the output signal with high state is produced, when described reference voltage is more than described sensing input voltage, produced
Output signal with low state；
Receive described output signal；And
When described output signal is located at described high state, described input power failure is optionally made.
9. method as claimed in claim 8, it is characterised in that produce sensing input voltage and produce sensing output voltage it
Before, it is also performed to following steps：
First pair of resistor is chosen, the first divider is constituted, second pair of resistor is chosen, the second divider is constituted；
Between described first node and earth terminal, the first described divider of connection；And
Between described Section Point and earth terminal, the second described divider of connection.
10. method as claimed in claim 8, it is characterised in that before comparing, be also performed to following steps：
Described sensing input voltage is connected to into the non-steering end of comparator；
Described reference voltage is connected to into the steering end of described comparator；And
The input offset voltage of described comparator is increased to into described offset voltage.
11. methods as claimed in claim 8, it is characterised in that it is described the step of optionally making input power fail it
Before, also provide the time delay for pre-setting.
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| CN201310105871.5A CN104078938B (en) | 2013-03-29 | 2013-03-29 | Detect the method and circuit of short circuit in asynchronous DC boost converter |
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| CN201310105871.5A CN104078938B (en) | 2013-03-29 | 2013-03-29 | Detect the method and circuit of short circuit in asynchronous DC boost converter |
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| Publication Number | Publication Date |
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| CN104078938A CN104078938A (en) | 2014-10-01 |
| CN104078938B true CN104078938B (en) | 2017-03-29 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US9819257B2 (en) * | 2015-07-10 | 2017-11-14 | Intersil Americas LLC | DC-to-DC converter input node short protection |
| CN105119476B (en) * | 2015-09-17 | 2018-01-02 | 矽力杰半导体技术(杭州)有限公司 | A kind of X capacitor discharge control circuit being applied in Switching Power Supply |
| CN105929299B (en) * | 2016-06-08 | 2019-04-30 | 北京联合大学 | A kind of electric car DC/DC low-voltage power supply and test circuit, equipment, system and test method |
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| CN201435598Y (en) * | 2008-10-29 | 2010-03-31 | Bcd半导体制造有限公司 | Short-circuit protective circuit of switch power supply PWM controller |
| CN102163834A (en) * | 2010-02-16 | 2011-08-24 | 安森美半导体贸易公司 | Switching control circuit |
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| CN104078938A (en) | 2014-10-01 |
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