CN206401881U - The anti-interference detection circuit of LED drive chip feedback pin - Google Patents
The anti-interference detection circuit of LED drive chip feedback pin Download PDFInfo
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- CN206401881U CN206401881U CN201621417375.9U CN201621417375U CN206401881U CN 206401881 U CN206401881 U CN 206401881U CN 201621417375 U CN201621417375 U CN 201621417375U CN 206401881 U CN206401881 U CN 206401881U
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Abstract
The utility model provides a kind of anti-interference detection circuit of LED drive chip feedback pin, including a detection circuit body, also include an immunity module, the immunity module is connected to the detection circuit body, for preventing a feedback detection voltage of the detection circuit body to be filtered more than a fixed threshold, and to the feedback detection voltage.A kind of anti-interference detection circuit of LED drive chip feedback pin of the present utility model can prevent the false triggering protection mechanism caused by feedback detection overtension; simultaneously can be on the basis of feedback detection voltage resonance detection not be influenceed; the interference of feedback detection voltage is effectively filtered out, the validity and accuracy of testing result is enhanced.
Description
Technical field
The utility model is related to anti-jamming circuit field, more particularly to LED drive chip feedback pin anti-interference detection
Circuit.
Background technology
The feedback pin (FB pins) of LED drive chip is applied not only to detection output and opens the abnormalities such as short circuit, while
Necessary time-series rules are provided for system worked well.When FB pins are interfered, the light then abnormal shadow of the work schedule of system
Ring constant current effect；It is heavy then be possible to the protection mechanism under false triggering chip abnormality, cause system not work.
At present, LED drive chip application circuit it is general by by the two ends of inductance or assists winding after electric resistance partial pressure with
The FB pins of chip be connected carry out detecting system open short-circuit abnormality, the demagnetized state of inductance and FB resonance.In switch OFF
Moment, due to the presence of leakage inductance, higher due to voltage spikes occurs when overturning in FB voltages；On the other hand due to FB pins and inductance
Or between assists winding two ends parasitic capacitance presence, when inductance both end voltage moment quickly overturn when parasitic capacitance intrinsic standoff ratio
More than the intrinsic standoff ratio of resistance, so that the voltage of FB pins is by rapid uplift to too high voltages.Caused by both the above reason
Switch OFF moment FB overtensions are likely to the output over-voltage protection mechanism of false triggering chip so that system can not be normal
Work.After normal turn-off is switched, due to LED drivings, to belong to Switching Power Supply itself noise jamming larger, if wiring
Lack of standardization or practical situations are severe, and what FB pins were subject to disturbs also more serious protecting so as to easy false triggering chip
The detection of mechanism or influence chip to demagnetization time and FB resonance causes work schedule abnormal.
Referring to Fig. 1, a kind of existing feedback pin detection circuit, it is not provided with anti-jamming circuit.In circuit, inductance or
The voltage at assists winding L0 ' two ends is after pull-up resistor Rup ' and pull down resistor Rdn ' partial pressures respectively as first comparator 111 '
With the positive and inverting input of the second comparator 114 '.The inverting input of first comparator 111 ' receives the first reference voltage
Signal vref1 '.First comparator 111 ' is used to detect that feedback detection voltage FB ' voltage status judges that short circuit is opened in output.D is triggered
Device 113 ' is triggered during switch OFF, switching signal swon '=0 by lead-edge-blanking signal leboff ' trailing edge, D triggerings
The Q ends output feedback detection voltage state signal FB_STAT ' of device 113 '.The inverting input of second comparator 114 ' receives the
Two reference voltage signal vref2 '.Second comparator 114 ' is used to detect inductance demagnetized state and feedback detection voltage FB resonance mistakes
Zero point.Rest-set flip-flop 115 ' locks the output result of the second comparator 114 ' during switch OFF, switching signal swon '=0
Deposit, the output end outputting inductance demagnetization end signal tdfin ' of rest-set flip-flop 115 '.
The working waveform figure of existing FB pins detection circuit see Fig. 2, due to the influence of leakage inductance, it is seen that input voltage
Vin ' occurs higher spike at switch OFF (switching signal swon '=0).In addition in switch OFF moment input voltage
Vin ' the rapid increase stages, because parasitic capacitance Cup ' and Cdn ' partial pressure effect cause feedback detection FB also to be raised rapidly,
Electric resistance partial pressure point is slowly then returned to, blanking signal leboff ' trailing edge will feed back detection voltage FB's ahead of the curve afterwards
Voltage status is exported.If feedback detection voltage FB overtension then slowly falls back to mistake the time required to electric resistance partial pressure value
It is long, then ahead of the curve blanking signal leboff ' trailing edges when be possible to sample feedback detection voltage FB over-pressed signal to touch
Power Generation Road connects the protection mechanism of chip.In addition after normal turn-off (switching signal swon '=0) is switched, due to switch electricity
Itself noise jamming of source is larger, if wiring is lack of standardization or practical situations are severe, feedback detection voltage FB
It heavily disturbed can may cause unexpected trigger protection mechanism, demagnetized state detection is abnormal, and Resonance detector is abnormal, so as to influence
Feedback detection voltage FB testing result.
The content of the invention
For above-mentioned deficiency of the prior art, the utility model provides a kind of the anti-dry of LED drive chip feedback pin
Detection circuit is disturbed, the false triggering protection mechanism caused by feedback detection overtension can be prevented, while can not influence anti-
On the basis of feedback detection voltage resonance detection, the interference of feedback detection voltage is effectively filtered out, the validity of testing result is enhanced
And accuracy.
To achieve these goals, the utility model provides a kind of anti-interference detection electricity of LED drive chip feedback pin
Road, including a detection circuit body, in addition to an immunity module, the immunity module are connected to the detection circuit sheet
Body, for preventing a feedback of the detection circuit body from detecting voltage more than a fixed threshold, and to the feedback detection electricity
Pressure is filtered.
Preferably, the detection circuit body includes：
One inductance or winding, the first end of the inductance or winding connect a voltage input end, the inductance or winding
Second end is grounded；
Two divider resistances, two divider resistance is serially connected, and divider resistance described in two connect to be formed one first string
Join and one first tie point is formed between branch road and the inductance or winding parallel, two divider resistance；
Two parasitic capacitances, two parasitic capacitance is serially connected, and parasitic capacitance described in two connect to be formed one second string
Join and one second tie point, second tie point are formed between branch road and the inductance or winding parallel, two parasitic capacitance
It is connected with first tie point；And
One signal output apparatus, the signal output apparatus connects a switch signal input end；
One first input end of the immunity module connects second tie point, the one second of the immunity module
Input connects the switch signal input end, and one first output end of the immunity module connects the signal output electricity
Road, one second output head grounding of the immunity module.
Preferably, the signal output apparatus includes：
One first comparator, the normal phase input end of the first comparator connects the first output of the immunity module
End, the inverting input of the first comparator connects one first reference voltage input terminal；
One first phase inverter, the input of first phase inverter connects a lead-edge-blanking signal input part；
One d type flip flop, the D ends of the d type flip flop connect the output end of the first comparator, the CLK of the d type flip flop
The output end of the end connection phase inverter, the reset terminal of the d type flip flop connects the switch signal input end；
One second comparator, the normal phase input end of second comparator connects one second reference voltage input terminal, described
The inverting input of second comparator connects the first output end of the immunity module；And
One rest-set flip-flop, the S ends of the rest-set flip-flop connect the output end of second comparator, the rest-set flip-flop
R ends connect the switch signal input end.
Preferably, the immunity module includes：
One metal-oxide-semiconductor, the first input end of the drain electrode connection immunity module of the metal-oxide-semiconductor, the source electrode of the metal-oxide-semiconductor
Connect the second output end of the immunity module；
One ON-OFF control circuit, the input of the ON-OFF control circuit connects the second input of the immunity module
End, the output end of the ON-OFF control circuit connects the grid of the metal-oxide-semiconductor；
One filter resistance, the filter resistance is connected to the first input end and the anti-interference mould of the immunity module
Between first output end of block；And
One filter capacitor, the top crown of the filter capacitor is connected to the first output end of the immunity module, described
The bottom crown ground connection of filter capacitor.
Preferably, the ON-OFF control circuit includes：
One second phase inverter, the input of second phase inverter connects the second input of the immunity module；
One time delay module, the input of the time delay module connects the output end of second phase inverter；And
One nor gate a, first input end of the nor gate connects the output end of the time delay module, the nor gate
One second input connect the switch signal input end, the output end of the nor gate connects the grid of the metal-oxide-semiconductor.
The utility model makes it have following beneficial effect as a result of above technical scheme：
Immunity module is connected to detection circuit body, for preventing the feedback detection voltage for detecting circuit body from exceeding
One fixed threshold, and feedback detection voltage is filtered, it can eliminate anti-caused by leakage inductance spike and parasitic capacitance partial pressure
The problem of feedback detection overtension flip chip protection mechanism；The internal feedback during switch OFF can be eliminated simultaneously detects voltage
Unexpected trigger protection mechanism caused by heavily disturbed, demagnetized state detection is abnormal, the problems such as Resonance detector is abnormal so that anti-
The detection of feedthrough voltage is relatively reliable accurate.ON-OFF control circuit is used to control the conducting of metal-oxide-semiconductor to turn off, filter resistance and filtered electrical
Appearance cooperatively forms filter circuit, realizes the filtering to feedback voltage.
Brief description of the drawings
Fig. 1 is the structural representation that existing feedback pin detects circuit；
Fig. 2 is the work wave comparison diagram that existing feedback pin detects circuit；
The structural representation of the anti-interference detection circuit of the LED drive chip feedback pin of Fig. 3 the utility model embodiments；
Fig. 4 is the work wave of the anti-interference detection circuit of the LED drive chip feedback pin of the utility model embodiment
Comparison diagram.
Embodiment
Below according to accompanying drawing 3-4, preferred embodiment of the present utility model is provided, and is described in detail, is enabled preferably
Understand function of the present utility model, feature.
Referring to Fig. 3, a kind of anti-interference detection circuit of LED drive chip feedback pin of the present utility model, including one
The immunity module 2 of circuit body 1 and one is detected, immunity module 2 is connected to detection circuit body 1, for preventing from detecting circuit
One feedback detection voltage of body 1 is filtered more than a fixed threshold, and to feedback detection voltage.
Wherein, detection circuit body 1 includes：One inductance or winding L0, two divider resistance Rup, Rdn, two parasitic capacitances
Cup, Cdn and a signal output apparatus 11.Inductance or winding L0 first end connect a voltage input end, receive input voltage
Vin, inductance or winding L0 the second end ground connection.Two divider resistance Rup, Rdn are serially connected, and two divider resistance Rup, Rdn go here and there
Join one first series arm formed in parallel with inductance or winding L0, one first is formed between two divider resistance Rup, Rdn and is connected
Point.Two parasitic capacitances Cup, Cdn are serially connected, and two parasitic capacitances Cup, Cdn connect one second series arm to be formed with electricity
Sense or winding L0 are in parallel, and one second tie point, the second tie point and the first tie point phase are formed between two parasitic capacitances Cup, Cdn
Even, the voltage at the first tie point and the second tie point is feedback detection voltage FB.The switch letter of the connection of signal output apparatus 11 one
Number input, and receive a switching signal swon.One first input end of immunity module 2 connects the second tie point, anti-interference
One second input connecting valve signal input part of module 2, the one first output end connection signal output electricity of immunity module 2
Road 11, one second output head grounding of immunity module 2.
In the present embodiment, signal output apparatus 11 includes：One first comparator 111, one first phase inverter 112, D triggerings
Device 113, one second comparator 114 and a rest-set flip-flop 115.Wherein, the normal phase input end connection of first comparator 111 is anti-interference
First output end of module 2, the inverting input of first comparator 111 connects one first reference voltage input terminal, and receives the
One reference voltage signal vref1.The input of first phase inverter 112 connects a lead-edge-blanking signal input part, and receives forward position
Blanking signal leboff.The D ends of d type flip flop 113 connect the output end of first comparator 111, the CLK ends connection of d type flip flop 113
The output end of phase inverter, the reset terminal connecting valve signal input part of d type flip flop 113 receives switching signal swon, d type flip flop
113 Q ends output feedback detection voltage state signal FB_STAT.The normal phase input end connection one second of second comparator 114 is joined
Voltage input end is examined, and receives the second reference voltage signal vref2, the inverting input connection of the second comparator 114 is anti-interference
First output end of module 2.The S ends of rest-set flip-flop 115 connect the output end of the second comparator 114, the R ends of rest-set flip-flop 115
Connecting valve signal input part, and receive switching signal swon, the output end outputting inductance demagnetization end signal of rest-set flip-flop 115
tdfin。
In the present embodiment, immunity module 2 includes：One metal-oxide-semiconductor M1, an ON-OFF control circuit 21, a filter resistance Rf and
One filter capacitor Cf.The first input end of metal-oxide-semiconductor M1 drain electrode connection immunity module 2, metal-oxide-semiconductor M1 source electrode connection is anti-interference
Second output end of module 2.The input of ON-OFF control circuit 21 connects the second input of immunity module 2, switch control
The output end connection metal-oxide-semiconductor M1 of circuit 21 grid.Filter resistance Rf is connected to the first input end of immunity module 2 and resisted dry
Between the first output end for disturbing module 2.Filter capacitor Cf top crown is connected to the first output end of immunity module 2, filtering
Electric capacity Cf bottom crown ground connection.
Wherein, ON-OFF control circuit 21 includes：One second phase inverter 221, a time delay module 222 and a nor gate 223.The
The input of two phase inverters 221 connects the second input of immunity module 2.The input connection second of time delay module 222 is anti-
The output end of phase device 221.One first input end of nor gate 223 connects the output end of time delay module 222, the one of nor gate 223
Second input connecting valve signal input part, receives switching signal swon, the output end connection metal-oxide-semiconductor M1's of nor gate 223
Grid, output switch control signal fbleb.
Operation principle of the present utility model is as follows：
Work as switch OFF, switching signal swon=0 moments, switch controlling signal fbleb upsets drive metal-oxide-semiconductor for high level
M1 is pulled down to feedback detection voltage FB, so as to suppress to feed back detection caused by leakage inductance spike and parasitic capacitance Cup, Cdn partial pressure
Voltage FB overtensions.In the present embodiment, the delay time of time delay module 222 is defaulted as 1us, and this delay time can be according to reality
Applicable cases are adjusted.Work as after switch OFF, switching signal swon=0 1us, switch controlling signal fbleb reverts to low level,
Metal-oxide-semiconductor M1 stops the drop-down to feedback detection voltage FB, and feedback detection voltage FB voltages rise to electric determined by divider resistance
At pressure.Lead-edge-blanking signal leboff trailing edges carry out the interim state by feedback detection voltage FB and latched directly by d type flip flop 113
Opened to switch next time, i.e. switching signal swon=1.Opened in switch controlling signal fbleb upsets for low level to next time
Open before (switching signal swon=1), feedback detection voltage FB voltage can still be done with the external world in itself by from circuit
Disturb, influence feedback detection voltage FB detection.Therefore the RC wave filters being made up of filter resistance Rf and filter capacitor Cf are again to anti-
Feedback detection voltage FB is filtered processing, so as to reduce feedback detection voltage FB's on the premise of inductance Resonance detector is not influenceed
Disturb burr.
Work wave of the present utility model see Fig. 4, as switching signal swon=0, switch controlling signal fble and
It is high level that lead-edge-blanking signal leboff is overturn simultaneously.There is due to voltage spikes due to the presence of leakage inductance in input voltage vin, due to
Switch controlling signal fbleb high level drives metal-oxide-semiconductor M1 to pull down feedback detection voltage FB, therefore in switch controlling signal
Feedback detection voltage FB=0 during fbleb=1.After switch controlling signal fbleb high level terminates, feedback detection voltage FB
Rise at input voltage vin normal resistance partial pressure.At the end of lead-edge-blanking signal leboff high level, its trailing edge will be current
Feedback detection voltage FB state output.Inductance demagnetization starts resonance after terminating, and is switched again when detecting harmonic wave the lowest point
Open switching signal swon=1.
Record above, preferred embodiment only of the present utility model is not limited to scope of the present utility model, this
Above-described embodiment of utility model can also make a variety of changes.I.e. every claims according to the present utility model application and
Simple, equivalent changes and modifications that description is made, fall within the claims of the utility model patent.
Claims (5)
1. a kind of anti-interference detection circuit of LED drive chip feedback pin, including a detection circuit body, it is characterised in that
Also include an immunity module, the immunity module is connected to the detection circuit body, for preventing the detection circuit
One feedback detection voltage of body is filtered more than a fixed threshold, and to the feedback detection voltage.
2. the anti-interference detection circuit of LED drive chip feedback pin according to claim 1, it is characterised in that described
Detection circuit body includes：
One inductance or winding, the first end of the inductance or winding connect a voltage input end, the second of the inductance or winding
End ground connection；
Two divider resistances, two divider resistance is serially connected, and divider resistance described in two connect to be formed one first series connection branch
One first tie point is formed between road and the inductance or winding parallel, two divider resistance；
Two parasitic capacitances, two parasitic capacitance is serially connected, and parasitic capacitance described in two connect to be formed one second series connection branch
One second tie point, second tie point and institute are formed between road and the inductance or winding parallel, two parasitic capacitance
The first tie point is stated to be connected；And
One signal output apparatus, the signal output apparatus connects a switch signal input end；
One first input end of the immunity module connects second tie point, one second input of the immunity module
The end connection switch signal input end, one first output end of the immunity module connects the signal output apparatus, institute
State one second output head grounding of immunity module.
3. the anti-interference detection circuit of LED drive chip feedback pin according to claim 2, it is characterised in that described
Signal output apparatus includes：
One first comparator, the normal phase input end of the first comparator connects the first output end of the immunity module, institute
The inverting input for stating first comparator connects one first reference voltage input terminal；
One first phase inverter, the input of first phase inverter connects a lead-edge-blanking signal input part；
One d type flip flop, the D ends of the d type flip flop connect the output end of the first comparator, and the CLK ends of the d type flip flop connect
The output end of the phase inverter is connect, the reset terminal of the d type flip flop connects the switch signal input end；
One second comparator, the normal phase input end of second comparator connects one second reference voltage input terminal, described second
The inverting input of comparator connects the first output end of the immunity module；And
One rest-set flip-flop, the S ends of the rest-set flip-flop connect the output end of second comparator, the R ends of the rest-set flip-flop
Connect the switch signal input end.
4. the anti-interference detection circuit of LED drive chip feedback pin according to claim 3, it is characterised in that described
Immunity module includes：
One metal-oxide-semiconductor, the first input end of the drain electrode connection immunity module of the metal-oxide-semiconductor, the source electrode connection of the metal-oxide-semiconductor
Second output end of the immunity module；
One ON-OFF control circuit, the input of the ON-OFF control circuit connects the second input of the immunity module, institute
The output end for stating ON-OFF control circuit connects the grid of the metal-oxide-semiconductor；
One filter resistance, the filter resistance is connected to the first input end and the immunity module of the immunity module
Between first output end；And
One filter capacitor, the top crown of the filter capacitor is connected to the first output end of the immunity module, the filtering
The bottom crown ground connection of electric capacity.
5. the anti-interference detection circuit of LED drive chip feedback pin according to claim 4, it is characterised in that described
ON-OFF control circuit includes：
One second phase inverter, the input of second phase inverter connects the second input of the immunity module；
One time delay module, the input of the time delay module connects the output end of second phase inverter；And
One nor gate a, first input end of the nor gate connects the output end of the time delay module, the one of the nor gate
Second input connects the switch signal input end, and the output end of the nor gate connects the grid of the metal-oxide-semiconductor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621417375.9U CN206401881U (en) | 2016-12-22 | 2016-12-22 | The anti-interference detection circuit of LED drive chip feedback pin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621417375.9U CN206401881U (en) | 2016-12-22 | 2016-12-22 | The anti-interference detection circuit of LED drive chip feedback pin |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206401881U true CN206401881U (en) | 2017-08-11 |
Family
ID=59511220
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621417375.9U Withdrawn - After Issue CN206401881U (en) | 2016-12-22 | 2016-12-22 | The anti-interference detection circuit of LED drive chip feedback pin |
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| CN (1) | CN206401881U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106786401A (en) * | 2016-12-22 | 2017-05-31 | 上海灿瑞科技股份有限公司 | The anti-interference detection circuit of LED drive chip feedback pin |
| CN108880196A (en) * | 2018-07-06 | 2018-11-23 | 电子科技大学 | A kind of dynamic lead-edge-blanking circuit |
| CN112379204A (en) * | 2020-11-18 | 2021-02-19 | 苏州美思迪赛半导体技术有限公司 | Drive port state detection circuit and method of drive circuit |
| CN116298473A (en) * | 2023-05-17 | 2023-06-23 | 湖南大学 | Non-contact measurement method, device, equipment and medium for chip pin voltage |
-
2016
- 2016-12-22 CN CN201621417375.9U patent/CN206401881U/en not_active Withdrawn - After Issue
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106786401A (en) * | 2016-12-22 | 2017-05-31 | 上海灿瑞科技股份有限公司 | The anti-interference detection circuit of LED drive chip feedback pin |
| CN106786401B (en) * | 2016-12-22 | 2019-01-29 | 上海灿瑞科技股份有限公司 | The anti-interference detection circuit of LED drive chip feedback pin |
| CN108880196A (en) * | 2018-07-06 | 2018-11-23 | 电子科技大学 | A kind of dynamic lead-edge-blanking circuit |
| CN112379204A (en) * | 2020-11-18 | 2021-02-19 | 苏州美思迪赛半导体技术有限公司 | Drive port state detection circuit and method of drive circuit |
| CN112379204B (en) * | 2020-11-18 | 2024-03-29 | 苏州美思迪赛半导体技术有限公司 | Driving port state detection circuit and method of driving circuit |
| CN116298473A (en) * | 2023-05-17 | 2023-06-23 | 湖南大学 | Non-contact measurement method, device, equipment and medium for chip pin voltage |
| CN116298473B (en) * | 2023-05-17 | 2023-08-08 | 湖南大学 | Non-contact measurement method, device, equipment and medium for chip pin voltage |
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Granted publication date: 20170811 Effective date of abandoning: 20190129 |