CN205546043U - Driver output current foldback circuit - Google Patents
Driver output current foldback circuit Download PDFInfo
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- CN205546043U CN205546043U CN201620072218.2U CN201620072218U CN205546043U CN 205546043 U CN205546043 U CN 205546043U CN 201620072218 U CN201620072218 U CN 201620072218U CN 205546043 U CN205546043 U CN 205546043U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
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Abstract
The utility model relates to a driver output current foldback circuit has solved the not enough of prior art, and technical scheme is: including light current power, switch gating module, short -circuit protection switch and the protection switch that opens circuit, the one end of short -circuit protection switch is connected with the forward transportation output of driver, and the other end of short -circuit protection switch and the negative output of driver end is connected, and the protection switch's that opens circuit one end is connected with the negative input end of load, and the protection switch's that opens circuit output is held with the negative output of driver and is connected, and the short -circuit protection switch and the protection switch that opens circuit are controlled conduction switch, the control end of short -circuit protection switch and open circuit protection switch the control end all with switch gating module 's output is connected, and switch gating module 's sense terminal sets the load with between the driver negative output end, switch gating module is by light current mains operated.
Description
Technical field
This utility model relates to switch power technology field, in particular for driver output overcurrent
Problem, it is provided that a kind of driver output overcurrent protection circuit.
Background technology
It is very big that small-sized electrical equipment with LED as representative received stream impact, particularly LED, is receiving
Easily cause irreversible device damage to when crossing stream impact, and in prior art, LED driver exists
It is maintained at constant floating voltage during output open circuit state, and floating voltage is generally higher than full load condition
Under output voltage.Experiment is learnt, under full load condition and light condition, driver input switch turns on
Time, (definable surpasses will not to produce overcurrent at driver outgoing position (i.e. in LED load position)
The electric current crossing LED load rated current is overcurrent, and LED load can be caused by overcurrent can not be extensive
Multiple damage)；After the conducting of driver input switch, keep Light Condition, now connect LED load,
Overcurrent is born in LED load.Especially for underloading LED load, the dash current of generation may
The several times of LED rated current can be reached.After the conducting of LED driver input switch, LED load is cut
Except connecting with LED load, referred to as LED heat plug, during this switching load, LED
Load all can bear overcurrent.Especially carry out LED heat plug when little load and have bigger
Overcurrent, LED load is caused fatal infringement.
Because during driver output open circuit, driver output voltage is stable (empty at a constant voltage
Carry voltage), the output electrolysis of driver stores big energy, when connecting load, the energy that electrolysis stores
Discharged by load, it is believed that the energy that output electrolysis stores is driver pair in hot plug process
Load produces the main cause of overcurrent.
Utility model content
The purpose of this utility model is to solve in above-mentioned prior art hot plug process driver to load
Producing overcurrent causes the small-sized electrical equipment with LED as representative to easily cause irreversible device damage
Problem, it is provided that a kind of driver output overcurrent protection circuit.
This utility model solves its technical problem and be the technical scheme is that a kind of driver exported
Stream protection circuit, is connected between driver positive output end with driver negative output terminal and has electric capacity, driver
Positive output end is connected with the positive input terminal of load by switch S or hot-plug interface, the negative input of load
End is connected with driver negative output terminal, driver negative output terminal ground connection, it is characterised in that: include light current
Power supply, switching gate module, protective switch of the short circuit and break protective switch, described protective switch of the short circuit
One end be connected with the positive output end of driver, the other end of protective switch of the short circuit is negative defeated with driver
Going out end to connect, one end of break protective switch is connected with the negative input end of load, break protective switch
Outfan is connected with the negative output terminal of driver, and protective switch of the short circuit and break protective switch are controlled
Conducting switch, the control end controlling end and break protective switch of protective switch of the short circuit all with described switch
The outfan of gating module connects, and the test side of switching gate module is disposed in described load and drives with described
Between dynamic device negative output terminal, described switching gate module is powered by light current power supply.This utility model is driving
The outgoing position of dynamic device circuit adds overcurrent protection link.Load generally refer to specified LED load or
The light LED load of person, (but do not limit and LED load, it is also possible to be other small-sized electrical equipments)
The moment connected, bypass channel turns on, and is discharged by the energy of output electrochemical capacitor, and driver exports
Being in short-circuit protection state, postpone a period of time disconnection bypass channel, load can normally start, both
Overcome the heavy current impact connecting load, can guarantee that again the normal work of driver, make the steady of system
Qualitative and reliability gets a promotion.What the driver in this utility model was conventional is transformator, driver
Positive output end generally refer to main transformer secondary side high voltage node, the negative output terminal of driver is general
Refer to main transformer secondary side lower voltage node.Light current power supply in this utility model is assisted by driver
Outfan supplies.
As preferably, described protective switch of the short circuit selects field effect transistor Q1, and described break protective switch selects
Field effect transistor Q2, described switching gate module is used to include the strobe signal circuits and detection signal circuit, inspection
The first input end surveying signal circuit is connected with driver negative output terminal, and the second of detection signal circuit is defeated
Entering end to be connected with load, the outfan of detection signal circuit is connected with the strobe signal circuits input, choosing
First outfan of messenger circuit is connected with the control end of short-circuit protection circuit, the strobe signal circuits
Second outfan is connected with the control end of breaking protection circuit.This utility model uses field effect transistor, main
If field effect transistor compares this circuit of adaptation, but be in addition to outside field effect transistor to select other can
Control switch, the form such as including audion or other integrated switch chips.I.e. after normal load is connected,
Ensureing that metal-oxide-semiconductor Q1 takes the lead in turning on, the energy release saved bit by bit by electrochemical capacitor, circuit is in short-circuit protection
State, before metal-oxide-semiconductor Q1 turns off, turns on metal-oxide-semiconductor Q2, can realize the normal startup of load,
LED load will not be produced excessive dash current.After needing proof load to connect, then connection is driven simultaneously
When moving the input switch of device, load can normally work.
As preferably, described the strobe signal circuits include a NE555 chip and the 2nd NE555 chip,
Electric capacity C2, electric capacity C11, electric capacity C21, electric capacity C22, resistance R11, resistance R13, resistance R21,
Diode D42, the GND end of a NE555 chip by electric capacity C11 ground connection and with a NE555
The TH end of chip connects, and the TH end of a NE555 chip and the DIS end of a NE555 chip are even
Connecing, the TH end of a NE555 chip is connected with light current power supply by resistance R11, a NE555 core
The Vc end of sheet passes through electric capacity C2 ground connection, and the vdd terminal of a NE555 chip is connected with light current power supply,
The MR end of the oneth NE555 chip is connected with light current power supply, the TR end of a NE555 chip and detection
First outfan of signal circuit connects, and the OUT terminal of a NE555 chip passes through resistance R13 and drives
The negative output terminal of dynamic device connects, and the OUT terminal of a NE555 chip is also with the grid of field effect transistor Q1 even
Connect, the GND end ground connection of the 2nd NE555 chip by electric capacity C21 and the TH of the 2nd NE555 chip
End connects, and the TH end of the 2nd NE555 chip and the DIS end of the 2nd NE555 chip connect, and second
The TH end of NE555 chip is connected with light current power supply by resistance R21, the Vc of the 2nd NE555 chip
End is by electric capacity C22 ground connection, and the vdd terminal of the 2nd NE555 chip is connected with light current power supply, the 2nd NE555
The MR end of chip is connected with light current power supply, the TR end of the 2nd NE555 chip and detection signal circuit
First outfan connects, and the OUT terminal of the 2nd NE555 chip is by the sun of resistance R2 and diode D42
Pole connects, and the negative electrode of diode D42 is connected with the grid of field effect transistor Q2, the negative electrode of diode D42
The most respectively by resistance R1 and electric capacity C1 ground connection.In this circuit, before switch S Guan Bi, electrochemical capacitor
C1 is in high energy storage state.When switching S Guan Bi, owing to metal-oxide-semiconductor Q2 does not turns on, at metal-oxide-semiconductor
Presenting high pressure at drain electrode, the colelctor electrode at audion Q31 presents low level, a NE555 intervalometer
Output signal present high level, metal-oxide-semiconductor Q1 and metal-oxide-semiconductor Q2 and sequentially turn on.NE555 intervalometer is only
It is preferably to select, selects degree higher, but other similar intervalometer or employings can also be selected
556 packing forms, corresponding scheme is considered as equivalent.
As preferably, described detection signal circuit include comparator U1, resistance R42, resistance R43,
Resistance R5, diode D41, audion Q41, resistance R32, resistance R33 and audion Q31, electricity
First end of resistance Rs is connected with the negative output terminal of driver, and second end of resistance Rs passes through field effect transistor
Q2 is connected with load, and first end of resistance Rs is by the negative input end of resistance R43 and comparator U1 even
Connecing, the negative input end of comparator U1 is connected with light current power supply by resistance R42, and comparator U1 is just
Input is connected with second end of resistance RS, the outfan of comparator U1 and the base stage of audion Q41
Connecting, the colelctor electrode of audion Q41 is connected with light current power supply, and the emitter stage of audion Q41 passes through two
Pole pipe D41 is connected with the grid of field effect transistor Q2, and the base stage of audion Q31 is by resistance R32 and bears
Carrying and connect, the emitter stage of audion Q31 is connected with the negative output terminal of driver, the collection of audion Q31
Electrode is connected with light current power supply by resistance R33, the colelctor electrode of audion Q31 and a NE555 core
The TR end of sheet connects, and the colelctor electrode of audion Q31 also TR end with the 2nd NE555 chip is connected.
At a NE555 chip, it is also possible to when selecting other similar intervalometer output points to be in low level, Q2
Turning on already, driver load can normally start.It is higher than at positive input terminal voltage comparator being detected
During negative input end voltage, comparator output high level, diode D41 turns on.At the 2nd NE555 chip
Output signal close have no progeny, the signal of metal-oxide-semiconductor Q2 is to exist always, and metal-oxide-semiconductor Q2 is constantly on,
The normal work of load.After the load some time disconnects, owing to the positive input terminal voltage of comparator reduces, compel
Making comparator be output as low level, metal-oxide-semiconductor Q2 turns off.The input connecting driver under normal condition is opened
Closing, driver the most normally works, and connects the LED load of various electric pressure, and load was not subjected to
The impact of electric current, effectively protects LED load.
As preferably, described the strobe signal circuits is single-chip microcomputer, and described light current power supply passes through voltage stabilizing chip
Be connected with microcontroller power supply end, single-chip microcomputer respectively with detection the first outfan of signal circuit and detection
Second outfan of signal circuit connects, and an outfan of single-chip microcomputer passes through resistance R1 and field effect transistor
The grid of Q1 connects, and the grid of field effect transistor Q1 passes through resistance R2 ground connection, and another of single-chip microcomputer is defeated
Going out end to be connected with the grid of field effect transistor Q2 by resistance R6, the grid of field effect transistor Q2 passes through resistance
R7 ground connection, the outfan of described single-chip microcomputer is pwm signal outfan.Utilize single chip machine controlling circuit,
Drain voltage and the sampling resistor Rs voltage that only need to detect metal-oxide-semiconductor Q2 i.e. can detect that closing of switch S
Close and disconnect, simulating LED heat swapping process.After single-chip microcomputer initializes, detect that high electricity occurs in A point
Flat, i.e. representation switch S closes, and sequentially turns on Q1, Q2, i.e. PWM1 and PWM2 output voltage is higher than
The threshold voltage of metal-oxide-semiconductor, needs to meet simultaneously and ensures that Q2 has been turned on before Q1 turns off；A point one
Straight there is not high level, represents that S is the most not closed, software cycle detection always.Normal circuit operation
After, sampling resistor E point voltage raises, and represents that LED load normally works, once detects that E points out
Existing low level, representation switch S disconnects, and need to reduce Q2 grid voltage, i.e. PWM2 pin exports low electricity
Flat, force Q2 to turn off, simulate LED heat swapping process, effectively protect LED load.
As preferably, described detection signal circuit includes comparator U1A, resistance Rs, resistance R3, electricity
Resistance R4, resistance R5, resistance R8, resistance R9 and audion Q3, first end of resistance Rs and driving
The negative output terminal of device connects, and second end of resistance Rs is connected with load by field effect transistor Q2, resistance
First end of Rs is connected by the negative input end of resistance R4 and comparator U1A, and comparator U1A's is negative
Input is connected with light current power supply by resistance R3, and the outfan of comparator U1A is connect by resistance R5
Ground, the outfan of comparator is connected with single-chip microcomputer as the second outfan of detection signal circuit, three poles
The base stage of pipe Q3 by resistance R8 with load is connected, the colelctor electrode of audion Q3 pass through resistance R9 and
Light current power supply connects, and the emitter stage of audion Q3 is connected with the negative output terminal of driver, audion Q3
Colelctor electrode as detection signal circuit the first outfan be connected with single-chip microcomputer.
As preferably, the resistance value of described resistance R11 is little with the product of the capacitance of described electric capacity C11
In the product of capacitance of resistance value and the described electric capacity C21 of described resistance R21, described comparator U1
Type selecting meet:
Ucc × (R43/ (R43+R42)) ＜ Rs × IRMS, wherein, Ucc represents that light current power supply exports
Voltage, exceedes the threshold voltage of the grid of field effect transistor, and Rs represents the sampling resistor of comparator positive input terminal
Value, IRMS represents the output-current rating virtual value of driver, R42 and R43 is corresponding resistance
Resistance value.
Substantial effect of the present utility model is: the outgoing position at drive circuit adds overcurrent protection
Link.In the moment that load is connected, bypass channel turns on, and is discharged by the energy of output electrochemical capacitor,
Driver output is in short-circuit protection state, postpones a period of time disconnection bypass channel, and load can be just
Often start, both overcome the heavy current impact connecting load, can guarantee that again the normal work of driver,
The stability and the reliability that make system get a promotion.
Accompanying drawing explanation
Fig. 1 is common driver output unit parallel circuit schematic diagram；
Fig. 2 is the main circuit diagram that the utility model proposes the protection of driver output overcurrent；
Fig. 3 is that this utility model driver output overcurrent protects sequential chart；
Fig. 4 is the driver output overcurrent protection circuit connection figure that the utility model proposes；
Fig. 5 is that the driver that the utility model proposes crosses stream output protection software controlled circuitry connection figure.
Detailed description of the invention
Below by specific embodiment, and combine accompanying drawing, the technical solution of the utility model is made into one
Illustrating of step.
Embodiment 1:
A kind of driver output overcurrent protection circuit (seeing accompanying drawing 2 to 4), overcomes prior art (ginseng
See accompanying drawing 1) technological deficiency, in the present embodiment, driver positive output end and driver negative output terminal
Between connect and have electric capacity, driver positive output end is the most defeated by switch S or hot-plug interface and load
Entering end to connect, the negative input end of load is connected with driver negative output terminal, driver negative output terminal ground connection,
Including light current power supply, the strobe signal circuits, detection signal circuit, the first gating switch and the second gating
Switch, described first gating switch control end and second gating control end switch respectively with described choosing
The outfan of messenger circuit connects, the first input end of detection signal circuit and driver negative output terminal
Connect, detection signal circuit the second input with load is connected, detect signal circuit outfan and
The strobe signal circuits input connects, the first end of described first gating switch and driver positive output end
Connecting, the second end of described first gating switch is connected with driver negative output terminal, described second gating
First end of switch is connected with load in series, and the second end of described second gating switch is born defeated with driver
Going out end to connect, the strobe signal circuits is powered by light current power supply.
Described first gating switch selects field effect transistor Q1, described second gating switch to select field effect transistor
Q2.Use this utility model field effect transistor, mainly field effect transistor compare this circuit of adaptation, but remove
Other gate-controlled switch can also be selected, including audion or other integrated switchs outside field effect transistor
The forms such as chip.I.e. after normal load is connected, it is ensured that metal-oxide-semiconductor Q1 takes the lead in turning on, will electrolysis electricity
The energy release that volume is collected together, circuit is in short-circuit protection state, before metal-oxide-semiconductor Q1 turns off, will
Metal-oxide-semiconductor Q2 turns on, and can realize the normal startup of load, will not produce excessive to LED load
Dash current.After needing proof load to connect, then when connecting the input switch of driver, load energy simultaneously
Enough normal work.Described the strobe signal circuits include a NE555 chip and the 2nd NE555 chip,
Electric capacity C2, electric capacity C11, electric capacity C21, electric capacity C22, resistance R11, resistance R13, resistance R21,
Diode D42, the GND end of a NE555 chip by electric capacity C11 ground connection and with a NE555
The TH end of chip connects, the TH end of a NE555 chip and the DIS end of a NE555 chip
Connecting, the TH end of a NE555 chip is connected with light current power supply by resistance R11, a NE555
The Vc end of chip passes through electric capacity C2 ground connection, and the vdd terminal of a NE555 chip is with light current power supply even
Connecing, the MR end of a NE555 chip is connected with light current power supply, the TR end of a NE555 chip
Being connected with the first outfan of detection signal circuit, the OUT terminal of a NE555 chip passes through resistance
R13 is connected with the negative output terminal of driver, the OUT terminal of a NE555 chip also with field effect transistor
The grid of Q1 connects, and the GND end ground connection of the 2nd NE555 chip also passes through electric capacity C21 and second
The TH end of NE555 chip connects, the TH end of the 2nd NE555 chip and the 2nd NE555 chip
DIS end connects, and the TH end of the 2nd NE555 chip is connected with light current power supply by resistance R21, the
The Vc end of two NE555 chips pass through electric capacity C22 ground connection, the vdd terminal of the 2nd NE555 chip with
Light current power supply connects, and the MR end of the 2nd NE555 chip is connected with light current power supply, the 2nd NE555
The TR end of chip is connected with the first outfan of detection signal circuit, the OUT of the 2nd NE555 chip
End is connected by the anode of resistance R2 with diode D42, the negative electrode of diode D42 and field effect transistor
The grid of Q2 connects, and the negative electrode of diode D42 is the most respectively by resistance R1 and electric capacity C1 ground connection.
Described detection signal circuit include comparator U1, resistance R42, resistance R43, resistance R5, two
Pole pipe D41, audion Q41, resistance R32, resistance R33 and audion Q31, the of resistance Rs
One end is connected with the negative output terminal of driver, and second end of resistance Rs passes through field effect transistor Q2 and load
Connecting, first end of resistance Rs is connected by the negative input end of resistance R43 and comparator U1, compares
The negative input end of device U1 is connected with light current power supply by resistance R42, the positive input terminal of comparator U1 and
Second end of resistance RS connects, and the outfan of comparator U1 is connected with the base stage of audion Q41, and three
The colelctor electrode of pole pipe Q41 is connected with light current power supply, and the emitter stage of audion Q41 passes through diode D41
Being connected with the grid of field effect transistor Q2, the base stage of audion Q31 is connected with load by resistance R32,
The emitter stage of audion Q31 is connected with the negative output terminal of driver, and the colelctor electrode of audion Q31 passes through
Resistance R33 is connected with light current power supply, the colelctor electrode of audion Q31 and the TR of a NE555 chip
End connects, and the colelctor electrode of audion Q31 also TR end with the 2nd NE555 chip is connected.Described electricity
The resistance value of resistance R11 and the product of the capacitance of the described electric capacity C11 resistance less than described resistance R21
The product of the capacitance of value and described electric capacity C21, the type selecting of described comparator U1 meets:
Ucc × (R43/ (R43+R42)) ＜ Rs × IRMS, wherein, Ucc represents that light current power supply exports
Voltage, exceedes the threshold voltage of the grid of field effect transistor, and Rs represents the sampling resistor of comparator positive input terminal
Value, IRMS represents the output-current rating virtual value of driver, R42 and R43 is corresponding resistance
Resistance value.
The present embodiment adds overcurrent protection link at the outgoing position of drive circuit.It is usually in load
Refer to specified LED load or light LED load, (but do not limit and LED load, it is also possible to
It is other small-sized electrical equipments) moment of connecting, bypass channel turns on, will the energy of output electrochemical capacitor
Amount discharges, and driver output is in short-circuit protection state, postpones a period of time disconnection bypass channel,
Load can normally start, and has both overcome the heavy current impact connecting load, can guarantee that again driver
Normal work, makes the stability of system and reliability get a promotion.Driver in the present embodiment is commonly used
Be transformator, the positive output end of driver generally refers to main transformer secondary side high voltage node, drives
The negative output terminal of dynamic device generally refers to main transformer secondary side lower voltage node.Light current in the present embodiment
Power supply is supplied by driver auxiliary output terminal.The present embodiment uses field effect transistor, mainly field effect transistor
Relatively adapt to this circuit, but be in addition to outside field effect transistor to select other gate-controlled switch, including
The forms such as audion or other integrated switch chips.Require i.e. after normal load is connected, it is ensured that
Metal-oxide-semiconductor Q1 takes the lead in turning on, and the energy release saved bit by bit by electrochemical capacitor, circuit is in short-circuit protection shape
State, before metal-oxide-semiconductor Q1 turns off, turns on metal-oxide-semiconductor Q2, can realize normally opening of load
Dynamic, LED load will not be produced excessive dash current.After needing proof load to connect, then connect simultaneously
When leading to the input switch of driver, load can normally work.In the present embodiment, a NE555
Chip, it is also possible to when selecting other similar intervalometer output points to be in low level, field effect transistor Q2 is already
Conducting, driver load can normally start.Defeated higher than negative at positive input terminal voltage comparator being detected
When entering terminal voltage, comparator output high level, diode D41 turns on.At the 2nd NE555 chip
Output signal is closed and is had no progeny, and the signal of metal-oxide-semiconductor Q2 is to exist always, and metal-oxide-semiconductor Q2 leads always
Logical, the normal work of load.After the load some time disconnects, owing to the positive input terminal voltage of comparator reduces,
Forcing comparator to be output as low level, metal-oxide-semiconductor Q2 turns off.The defeated of driver is connected under normal condition
Entering switch, driver the most normally works, and connects the LED load of various electric pressure, and load is no longer held
Impacted by overcurrent, effectively protected LED load.In this circuit, before switch S Guan Bi, electrolysis electricity
Hold C1 and be in high energy storage state.When switching S Guan Bi, owing to metal-oxide-semiconductor Q2 does not turns on, at MOS
Presenting high pressure at the drain electrode of pipe, the colelctor electrode at audion Q31 presents low level, and a NE555 is fixed
Time device output signal present high level, metal-oxide-semiconductor Q1 and metal-oxide-semiconductor Q2 and sequentially turn on.NE555
Intervalometer the most preferably selects, and selects degree higher, but can also select other similar intervalometers
Or using 556 packing forms, corresponding scheme is considered as equivalent.
Embodiment 2:
The present embodiment (seeing accompanying drawing 5) is identical with embodiment 1 basic ideas and principle, range of application
Similar, difference is: described the strobe signal circuits is single-chip microcomputer, and described light current power supply is by steady
Pressure chip be connected with microcontroller power supply end, single-chip microcomputer respectively with detect signal circuit the first outfan with
And the second outfan of detection signal circuit connects, an outfan of single-chip microcomputer passes through resistance R1 and field
The grid of effect pipe Q1 connects, and the grid of field effect transistor Q1 passes through resistance R2 ground connection, single-chip microcomputer
Another outfan is connected with the grid of field effect transistor Q2 by resistance R6, the grid of field effect transistor Q2
Resistance R7 ground connection is passed through in pole, and the outfan of described single-chip microcomputer is pwm signal outfan.Described inspection
Survey signal circuit and include comparator U1A, resistance Rs, resistance R3, resistance R4, resistance R5, electricity
First end of resistance R8, resistance R9 and audion Q3, resistance Rs is connected with the negative output terminal of driver,
Second end of resistance Rs is connected with load by field effect transistor Q2, and first end of resistance Rs is by electricity
The negative input end of resistance R4 and comparator U1A is connected, and the negative input end of comparator U1A passes through resistance
R3 is connected with light current power supply, and the outfan of comparator U1A passes through resistance R5 ground connection, comparator defeated
Going out end to be connected with single-chip microcomputer as the second outfan detecting signal circuit, the base stage of audion Q3 is passed through
Resistance R8 is connected with load, and the colelctor electrode of audion Q3 is connected with light current power supply by resistance R9,
The emitter stage of audion Q3 is connected with the negative output terminal of driver, and the colelctor electrode of audion Q3 is as inspection
The first outfan surveying signal circuit is connected with single-chip microcomputer.Utilize single chip machine controlling circuit, only need detection
The drain voltage of metal-oxide-semiconductor Q2 and sampling resistor Rs voltage i.e. can detect that the Guan Bi of switch S and breaks
Open, simulate LED heat swapping process.After single-chip microcomputer initializes, detect that A point high level occurs, i.e.
Representation switch S closes, and sequentially turns on Q1, Q2, i.e. PWM1 and PWM2 output voltage is higher than
The threshold voltage of metal-oxide-semiconductor, needs to meet simultaneously and ensures that Q2 has been turned on before Q1 turns off；A
There is not high level always in point, represents that S is the most not closed, software cycle detection always.Circuit is normal
After work, sampling resistor E point voltage raises, and represents that LED load normally works, E once detected
There is low level in point, and representation switch S disconnects, and need to reduce Q2 grid voltage, i.e. PWM2 pin is defeated
Go out low level, force Q2 to turn off, simulate LED heat swapping process, effectively protect LED load.
Embodiment described herein adds overcurrent protection link at the outgoing position of drive circuit.?
The moment that load is connected, bypass channel turns on, and is discharged by the energy of output electrochemical capacitor, driver
Output is in short-circuit protection state, postpones a period of time disconnection bypass channel, and load can normally start,
Both overcome the heavy current impact connecting load, and can guarantee that again the normal work of driver, make system
Stability and reliability get a promotion.
Embodiment described above is one of the present utility model preferably scheme, not to this practicality
Novel make any pro forma restriction, on the premise of without departing from the technical scheme described in claim
Also has other variant and remodeling.
Claims (7)
1. a driver output overcurrent protection circuit, between driver positive output end and driver negative output terminal
Connecting and have electric capacity, driver positive output end is by switch S or hot-plug interface and the positive input terminal of load
Connecting, the negative input end of load is connected with driver negative output terminal, driver negative output terminal ground connection, its
It is characterised by: include light current power supply, switching gate module, protective switch of the short circuit and break protective switch,
One end of described protective switch of the short circuit is connected with the positive output end of driver, another of protective switch of the short circuit
End is connected with the negative output terminal of driver, and one end of break protective switch is connected with the negative input end of load,
The outfan of break protective switch is connected with the negative output terminal of driver, and protective switch of the short circuit and open circuit are protected
Protect switch and be controlled conducting switch, the control end of protective switch of the short circuit and the control of break protective switch
End all outfans with described switching gate module are connected, and the test side of switching gate module is disposed in institute
Stating between load and described driver negative output terminal, described switching gate module is powered by light current power supply.
Driver output overcurrent protection circuit the most according to claim 1, it is characterised in that: described short
Field effect transistor Q1 selected by road protection switch, and described break protective switch selects field effect transistor Q2, described
Switching gate module includes the strobe signal circuits and detection signal circuit, and the first of detection signal circuit is defeated
Entering end to be connected with driver negative output terminal, the second input of detection signal circuit is connected with load, inspection
The outfan surveying signal circuit is connected with the strobe signal circuits input, and the first of the strobe signal circuits is defeated
Going out end to be connected with the control end of short-circuit protection circuit, the second outfan of the strobe signal circuits is protected with open circuit
The control end of protection circuit connects.
Driver output overcurrent protection circuit the most according to claim 2, it is characterised in that: described choosing
Messenger circuit include a NE555 chip and the 2nd NE555 chip, electric capacity C2, electric capacity C11,
Electric capacity C21, electric capacity C22, resistance R11, resistance R13, resistance R21, diode D42, first
The GND end of NE555 chip is connected by electric capacity C11 ground connection the TH end with a NE555 chip,
The TH end of the oneth NE555 chip and the DIS end of a NE555 chip connect, a NE555 chip
TH end be connected with light current power supply by resistance R11, the Vc end of a NE555 chip passes through electric capacity
C2 ground connection, the vdd terminal of a NE555 chip is connected with light current power supply, the MR of a NE555 chip
End is connected with light current power supply, the TR end of a NE555 chip and the first outfan detecting signal circuit
Connecting, the OUT terminal of a NE555 chip is connected with the negative output terminal of driver by resistance R13,
The OUT terminal of the oneth NE555 chip is also connected with the grid of field effect transistor Q1, the 2nd NE555 chip
GND end ground connection is also connected by the TH end of electric capacity C21 and the 2nd NE555 chip, the 2nd NE555 core
The TH end of sheet and the DIS end of the 2nd NE555 chip connect, and the TH end of the 2nd NE555 chip passes through
Resistance R21 is connected with light current power supply, and the Vc end of the 2nd NE555 chip passes through electric capacity C22 ground connection, the
The vdd terminal of two NE555 chips is connected with light current power supply, the MR end of the 2nd NE555 chip and light current electricity
Source connects, and the TR end of the 2nd NE555 chip is connected with the first outfan of detection signal circuit, and second
The OUT terminal of NE555 chip is connected by the anode of resistance R2 and diode D42, diode D42's
Negative electrode is connected with the grid of field effect transistor Q2, the negative electrode of diode D42 the most respectively by resistance R1 and
Electric capacity C1 ground connection.
Driver output overcurrent protection circuit the most according to claim 3, it is characterised in that: described inspection
Survey signal circuit include comparator U1, resistance R42, resistance R43, resistance R5, diode D41,
Audion Q41, resistance R32, resistance R33 and audion Q31, first end of resistance Rs and driving
The negative output terminal of device connects, and second end of resistance Rs is connected with load by field effect transistor Q2, resistance
First end of Rs is connected by the negative input end of resistance R43 and comparator U1, and comparator U1's is negative defeated
Enter end to be connected with light current power supply by resistance R42, the of the positive input terminal of comparator U1 and resistance RS
Two ends connect, and the outfan of comparator U1 is connected with the base stage of audion Q41, the collection of audion Q41
Electrode is connected with light current power supply, and the emitter stage of audion Q41 is by diode D41 and field effect transistor Q2
Grid connect, the base stage of audion Q31 by resistance R32 with load be connected, audion Q31's
Emitter stage is connected with the negative output terminal of driver, and the colelctor electrode of audion Q31 passes through resistance R33 with weak
Electricity power supply connects, and the colelctor electrode of audion Q31 and the TR end of a NE555 chip connect, audion
The colelctor electrode of Q31 also TR end with the 2nd NE555 chip is connected.
Driver output overcurrent protection circuit the most according to claim 2, it is characterised in that: described choosing
Messenger circuit is single-chip microcomputer, and described light current power supply is connected with microcontroller power supply end by voltage stabilizing chip,
Single-chip microcomputer respectively with detection signal circuit the first outfan and detection signal circuit the second outfan
Connecting, an outfan of single-chip microcomputer is connected with the grid of field effect transistor Q1 by resistance R1, and field is imitated
Should the grid of pipe Q1 by resistance R2 ground connection, another outfan of single-chip microcomputer passes through resistance R6 and field
The grid of effect pipe Q2 connects, and the grid of field effect transistor Q2 passes through resistance R7 ground connection, described single-chip microcomputer
Outfan be pwm signal outfan.
Driver output overcurrent protection circuit the most according to claim 5, it is characterised in that: described inspection
Survey signal circuit and include comparator U1A, resistance Rs, resistance R3, resistance R4, resistance R5, resistance
R8, resistance R9 and audion Q3, first end of resistance Rs is connected with the negative output terminal of driver, electricity
Second end of resistance Rs is connected with load by field effect transistor Q2, and first end of resistance Rs passes through resistance
R4 is connected with the negative input end of comparator U1A, the negative input end of comparator U1A by resistance R3 with
Light current power supply connects, and the outfan of comparator U1A passes through resistance R5 ground connection, and the outfan of comparator is made
The second outfan for detection signal circuit is connected with single-chip microcomputer, and the base stage of audion Q3 passes through resistance
R8 is connected with load, and the colelctor electrode of audion Q3 is connected with light current power supply by resistance R9, audion
The emitter stage of Q3 is connected with the negative output terminal of driver, and the colelctor electrode of audion Q3 is as detection signal
First outfan of circuit is connected with single-chip microcomputer.
Driver output overcurrent protection circuit the most according to claim 4, it is characterised in that: described electricity
The resistance value of resistance R11 and the product of the capacitance of the described electric capacity C11 resistance less than described resistance R21
The product of the capacitance of value and described electric capacity C21, the type selecting of described comparator U1 meets:
Ucc × (R43/ (R43+R42)) ＜ Rs × IRMS, wherein, Ucc represents light current electric power output voltage,
Exceeding the threshold voltage of the grid of field effect transistor, Rs represents the sampling resistor value of comparator positive input terminal, IRMS
Representing the output-current rating virtual value of driver, R42 and R43 is the resistance value of corresponding resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620072218.2U CN205546043U (en) | 2016-01-25 | 2016-01-25 | Driver output current foldback circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620072218.2U CN205546043U (en) | 2016-01-25 | 2016-01-25 | Driver output current foldback circuit |
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| CN205546043U true CN205546043U (en) | 2016-08-31 |
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| CN201620072218.2U Expired - Fee Related CN205546043U (en) | 2016-01-25 | 2016-01-25 | Driver output current foldback circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105680679A (en) * | 2016-01-25 | 2016-06-15 | 浙江凯耀照明股份有限公司 | Driver output overcurrent protection circuit and protection method |
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2016
- 2016-01-25 CN CN201620072218.2U patent/CN205546043U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105680679A (en) * | 2016-01-25 | 2016-06-15 | 浙江凯耀照明股份有限公司 | Driver output overcurrent protection circuit and protection method |
| CN105680679B (en) * | 2016-01-25 | 2018-10-02 | 浙江凯耀照明股份有限公司 | Driver output overcurrent protects circuit and its guard method |
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