CN109274073A - Short-circuit protection circuit and the switch converters for applying it - Google Patents
Short-circuit protection circuit and the switch converters for applying it Download PDFInfo
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- CN109274073A CN109274073A CN201810919834.0A CN201810919834A CN109274073A CN 109274073 A CN109274073 A CN 109274073A CN 201810919834 A CN201810919834 A CN 201810919834A CN 109274073 A CN109274073 A CN 109274073A
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- reference signal
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/1213—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for DC-DC converters
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- Dc-Dc Converters (AREA)
Abstract
This application discloses a kind of short-circuit protection circuit and using its switch converters.When the technical solution of the embodiment of the present invention detects output voltage recovery to more than reference signal by output voltage detecting circuit, it generates the first control signal of effective status and maintains the predetermined time, within the predetermined time, reference signal generation circuit opens soft reference signal and is pulled low to zero from current value, so that switch converters stop working, the thermal compensation signal for characterizing output voltage and desired output voltage difference is pulled low to zero simultaneously, at the end of the predetermined time, the soft reference signal that opens is started from scratch rising, switch converters are started to work, improve the functional reliability of short-circuit protection circuit.
Description
Technical field
The present invention relates to power electronic technique, and in particular to field of switch power relates more specifically to short-circuit protection circuit
And the switch converters using it.
Background technique
Switch converters are widely used in the electronic products such as mobile device, it usually needs short-circuit protection function, to prevent
Electric current is excessive when short-circuit burns out power device and load.Currently, switch converters mostly use PWM control mode, pass through
Limitation flows through the peak point current mode of power tube to achieve the purpose that short-circuit protection.In the short-circuit state, switch converters are usual
Close one several periods, work soft-start period.When short trouble within the period that switch converters work normally and compares
When the aft section of closer soft-start period releases, since actual soft-start time is inadequate, the output electricity of switch converters
Operating voltage can not be completely recovered to by being pressed in this soft-start period, therefore switch converters are still in short-circuit protection state,
Cause system loss.If the output voltage of the remaining enough switch converters of soft-start time is restored to operating voltage, still
Short trouble release when soft starting circuit generate the soft reference signal that opens have been raised to certain value, and at this time output voltage from
Zero begins to ramp up, to weaken the effect of soft start, output voltage and electric current are overshooted, and causes to damage to power device and load
Evil.
Summary of the invention
In view of this, the embodiment of the invention provides a kind of short-circuit protection circuit, switch converters when reducing short-circuit protection
Power consumption effectively prevent the generation of surge current and overshoot voltage, improve short-circuit protection circuit while when short trouble releases
Reliability.
According to a first aspect of the embodiments of the present invention, a kind of short-circuit protection circuit is provided, comprising:
Output voltage detecting circuit for receiving the feedback signal of characterization output voltage, and by the feedback signal and is joined
It examines signal to compare, generates first control signal；
Reference signal generation circuit for receiving the first control signal, and generates and soft opens reference signal；
Wherein, at the time of the feedback signal rises to the reference signal, the first control signal jump is to have
Effect state is simultaneously kept for a predetermined time, to keep dragging down the soft reference signal that opens to zero, so that institute within the predetermined time
Switch converters are stated to stop working.
Preferably, the initial time of the predetermined time by it is described it is soft open reference signal and be pulled down to zero from current value,
At the end of the predetermined time, the soft reference signal that opens is started from scratch slow rising, while the switch converters start work
Make, wherein the current value is greater than zero.
Preferably, thermal compensation signal holding is pulled low to zero simultaneously within the predetermined time by the short-circuit protection circuit, with
The inductive current of the switch converters is dragged down to zero, wherein the thermal compensation signal characterizes the output voltage and desired output electricity
The difference of pressure.
Preferably, when the feedback signal be less than the reference signal when, and when it is described it is soft open reference signal rise to it is pre-
When definite value, the output voltage detecting circuit generates the second control signal of effective status, the reference signal generation circuit root
Baseline restoration signal is generated according to the second control signal, enters short circuit protection mode to control the switch converters.
Preferably, the short-circuit protection circuit further includes a control circuit, to receive the baseline restoration signal and institute
First control signal is stated to generate driving signal；
When the second control signal is effective status, the switch converters are believed according to the driving signal and clock
Number switch between dormant state and switch state, when the first control signal is effective status, the switch converters
It stops working.
Preferably, the output voltage detecting circuit includes:
Comparison circuit is used for the feedback signal and reference signal, generates short-circuit signal；
First logic circuit is connect with the output end of the comparison circuit, for that will pass through the short-circuit signal of delay process
Logical operation is carried out with the short-circuit signal to generate the first control signal.
Preferably, first logic circuit also receives start completion signal, and with the short-circuit signal and will be at delay
The short-circuit signal of reason makees logical operation to generate second control signal, wherein the start completion signal is for characterizing the switch
Converter completes start-up course.
Preferably, first logic circuit includes:
Delay circuit, for postponing the short-circuit signal with predetermined delay time；
With door comprising the first input end being connect with the output end of the delay circuit, it is defeated with the comparison circuit
The second input terminal for being used to receive the short-circuit signal of outlet connection, receives the third input terminal of the start completion signal,
Generate the in-phase output end and reversed-phase output of the second control signal；
Pulse generation circuit is connect with described with the reversed-phase output of door to generate the first control signal.
Preferably, the delay circuit includes:
First resistor, first end are connected to the output end of the comparison circuit, and second end is connected to the with door
One input terminal；
First capacitor, first end are connected to the second end of the first resistor, second end ground connection.
Preferably, the one-shot circuit includes:
Second capacitor, first end are connected to the reversed-phase output with door, second end output the first control letter
Number；
Second resistance, first end are connected to the second end of second capacitor, second end ground connection.
Preferably, the reference signal generation circuit includes:
Detection circuit, for detect it is described it is soft open reference signal, when the soft reference signal that opens rises to predetermined value, generate
Soft open completes signal；
Second logic circuit completes signal for receiving soft open, and first control signal and second control signal are simultaneously made
Logical operation, to generate baseline restoration signal；
Voltage generation circuit, for dragging down the soft reference signal that opens in the effective status of the baseline restoration signal
To zero, the soft reference signal that opens is controlled in the invalid state of the baseline restoration signal from liter above freezing.
Preferably, when the first control signal is effective status, the baseline restoration signal is in the predetermined time
It is interior while remaining effective status, it soft open reference signal holding to control the voltage generation circuit for described and is pulled low to zero.
Preferably, the control circuit includes a trigger, and benchmark described in the clock input of the trigger is multiple
Position signal, input terminal are connect with in-phase output end, and clear input receives the first control signal, are generated in in-phase output end
Driving signal with the first level and second electrical level；
Wherein, when the second control signal is effective status, when the driving signal is the first level, the switch
Code converter work is in the dormant state, and when the driving signal is second electrical level, the switched mode converter work is in institute
State switch state.
Preferably, when the first control signal is effective status, the driving signal is maintained at the first level state,
The switch converters stop working.
According to a second aspect of the embodiments of the present invention, a kind of switch converters are provided, the short circuit including above-mentioned first aspect
Protect circuit, further includes:
Sample circuit is connect to generate the feedback letter of the characterization output voltage with the output end of the switch converters
Number；
Error circuit, according to the feedback signal, soft reference signal and the reference voltage of opening generates the thermal compensation signal；
Driving circuit, according to the thermal compensation signal, the driving signal and clock signal control of the short-circuit protection circuit output
Make the working condition of the switch converters.
Preferably, the switch converters further include first switch, and the first switch is connected to the error circuit
Output end；When the first control signal is effective, thermal compensation signal holding is pulled low to zero by the first switch closure.
The technical solution of the embodiment of the present invention detects output voltage recovery to more than reference by output voltage detecting circuit
It when signal, generates the first control signal of effective status and maintains the predetermined time, within the predetermined time, reference signal is generated
Circuit opens soft reference signal and is pulled low to zero from current value, so that switch converters stop working, while will characterize output voltage
It is pulled low to zero with the thermal compensation signal of desired output voltage difference, at the end of the predetermined time, the soft reference signal that opens is opened from zero
Begin to rise, switch converters are started to work, and the functional reliability of short-circuit protection circuit is improved.
Detailed description of the invention
By referring to the drawings to the description of the embodiment of the present invention, the above and other purposes of the present invention, feature and
Advantage will be apparent from, in the accompanying drawings:
Fig. 1 is the circuit block diagram of the short-circuit protection circuit of the embodiment of the present invention；
Fig. 2 is the circuit diagram of output voltage detecting circuit of the embodiment of the present invention；
Fig. 3 is the circuit diagram of the reference signal generation circuit of the embodiment of the present invention；
Fig. 4 is the circuit diagram of the control circuit of the embodiment of the present invention；
Fig. 5 is the circuit diagram of the switch converters of the embodiment of the present invention；
Fig. 6 is the working waveform figure of the short-circuit protection circuit of the embodiment of the present invention.
Specific embodiment
Below based on embodiment, present invention is described, but the present invention is not restricted to these embodiments.Under
Text is detailed to describe some specific detail sections in datail description of the invention.Do not have for a person skilled in the art
The present invention can also be understood completely in the description of these detail sections.In order to avoid obscuring essence of the invention, well known method, mistake
There is no narrations in detail for journey, process, element and circuit.
In addition, it should be understood by one skilled in the art that provided herein attached drawing be provided to explanation purpose, and
What attached drawing was not necessarily drawn to scale.
It will also be appreciated that in the following description, " circuit " refers to be passed through electrically by least one element or sub-circuit
The galvanic circle that connection or electromagnetism connect and compose.When title element or the " connection of another element of circuit " being connected to " or element/circuit
" between two nodes when, it, which can be, is directly coupled or connected another element or there may be intermediary element, element it
Between connection can be physically, in logic or its combination.On the contrary, when claiming element " being directly coupled to " or " directly connecting
Be connected to " another element when, it is meant that the two be not present intermediary element.
Unless the context clearly requires otherwise, "include", "comprise" otherwise throughout the specification and claims etc. are similar
Word should be construed as the meaning for including rather than exclusive or exhaustive meaning；That is, be " including but not limited to " contains
Justice.
In the description of the present invention, it is to be understood that, term " first ", " second " etc. are used for description purposes only, without
It can be interpreted as indication or suggestion relative importance.In addition, in the description of the present invention, unless otherwise indicated, the meaning of " multiple "
It is two or more.
With reference to Fig. 1, it show the schematic block circuit diagram of short-circuit protection circuit according to an embodiment of the present invention.
Short-circuit protection circuit 10 includes output voltage detecting circuit 11 and reference signal generation circuit 12.Output voltage detection
Circuit 11 receives the feedback signal FB of the output voltage of characterization switch converters, by comparing feedback signal FB and reference signal
Vref, to generate first control signal Vc1.Reference signal generation circuit 12 receives first control signal Vc1, soft opens base to generate
Calibration signal SS.When the short trouble of switch converters releases, the output voltage of switch converters, which follows, soft opens reference signal SS
It is gradually increasing, while feedback signal FB increases, when feedback signal FB rises to reference signal Vref, first control signal Vc1 is jumped
Become effective status and kept for the predetermined time, within the predetermined time, first control signal Vc1 is by reference signal generation circuit
The 12 soft reference signal SS that open generated keep being pulled low to zero, so that switch converters stop working.
Specifically, when short trouble releases, the soft reference signal SS that opens is raised to certain value from above freezing, when the first control
When signal Vc1 jump is effective status, reference signal generation circuit 12 opens soft reference signal SS and is pulled low to zero from current value, when
At the end of the predetermined time, reference signal generation circuit 12 controls the soft reference signal SS that opens and starts from scratch slow rising, simultaneously
Switch converters are started to work.When first control signal Vc1 jump is effective status, short-circuit protection circuit 10 simultaneously will compensation
Signal holding is pulled low to zero, so that the inductive current of switch converters is pulled low to zero, can not decline in time to avoid inductive current,
The wherein difference of the output voltage of thermal compensation signal characterization switch converters and desired output voltage.
Short-circuit protection circuit 10 further includes control circuit 13.It is soft to open reference signal in the start-up course of switch converters
Reference voltage of the SS as the voltage control loop of switch converters, switch converters control output electricity by voltage control loop
Pressure follows the soft reference signal SS that opens slowly to rise, when it is soft open reference signal SS and rise to predetermined value when, reference signal generation circuit
12 generate the start completion signal SS_OK of effective status, complete start-up course to characterize switch converters.Output signal detection electricity
Road 11 receives start completion signal SS_OK, with the output voltage state of detection switch converter, therefore in the embodiment of the present invention
If short-circuit protection electricity 10 occurs just work when short trouble only after switch converters start completion.After start completion,
The output voltage of switch converters it is constant be maintained at desired output.When short trouble occurs for switch converters, switch becomes
The output voltage rapid decrease of parallel operation, feedback signal FB drop to less than reference signal Vref, and output voltage detecting circuit 11 produces
Raw second control signal Vc2.Reference signal generation circuit 12 receives second control signal Vc2 and generates baseline restoration signal SS_
Rst, short-circuit protection circuit 10 enter short circuit protection mode, and control circuit 13 is controlled according to baseline restoration signal SS_rst and first
Signal Vc1 generates driving signal Vd with the working condition of control switch converter, so that limit switch converter exports electric current
Size.When second control signal Vc2 is effective status, switch converters are according to driving signal Vd and clock signal in suspend mode shape
Switch between state and switch state, wherein clock signal is used for the working frequency of configuration switch converter.When short trouble release,
Control circuit 13 receives the first control signal Vc1 of effective status, exports invalid driving signal Vd, while soft opening reference signal
SS holding is pulled low to zero, and switch converters stop working, until the soft reference signal SS that opens starts from scratch rising.
With reference to Fig. 2, it show the circuit diagram of output voltage detecting circuit according to an embodiment of the present invention.Output voltage detection
Circuit 20 includes comparator 21 and the first logic circuit 22.The first input end (for example, non-inverting input terminal) of comparator 21 receives
Reference signal Vref, the second input terminal (for example, inverting input terminal) receive feedback signal FB, when feedback signal FB is less than with reference to letter
Number Vref, comparator 21 export the effective short-circuit signal Short of high level.The output end of first logic circuit 22 and comparator 21
Connection, for the short-circuit signal of delay process and original short-circuit signal Short to be made logical operation to generate first control signal
Vc1.First logic circuit 22 also receives start completion signal SS_OK, and with short-circuit signal Short and through the short circuit of delay process
Signal makees logical operation to generate second control signal Vc2.
Specifically, the first logic circuit 22 includes delay circuit 221, with door 222 and pulse generation circuit 223.Delay
The input terminal of circuit 221 is connected to the output end of comparator 21 and postpones to short-circuit signal Short.With the first of door 222
Input terminal is connected to the output end of delay circuit 221 and receives delayed short-circuit signal, and the second input terminal is connected to comparator
21 output end simultaneously receives short-circuit signal Short, and third input terminal receives start completion signal SS_OK, when the input with door 222
When end signal is that high level is effective, second control signal Vc2 is generated with the in-phase output end of door 222.Pulse generation circuit
223 input terminal is connected to the reversed-phase output with door 222.When feedback signal FB rises to reference signal Vref, comparator
The short-circuit signal Short of 21 outputs is low level, and second control signal Vc2 is low level, pulse by the jump of effective high level
Generation circuit 223 generates the first control signal Vc1 of effective status and is kept for the predetermined time.
Delay circuit 221 as shown in Figure 2 further comprises resistance R1 and capacitor C1, to provide certain delay.Resistance
The first end of R1 is connected to the output end of comparator 21 to receive short-circuit signal Short, and second end is connected to first with door 222
Input terminal is to provide delayed short-circuit signal.The first end of capacitor C1 is connected to the second end of resistance R1, second end ground connection.
Delay circuit 221 further includes diode D1, is delayed for the rising edge to short-circuit signal.It should be understood that the resistance value of resistance R1
It can be selected as predetermined value with the capacitance of capacitor C1, to provide scheduled delay time.Delay circuit in the present embodiment with
Scheduled delay only postpones the rising edge of short-circuit signal Short, and the circuit structure that other can be realized above-mentioned function is equal
It can be applied in the present embodiment.
Pulse generation circuit further comprises resistance R2 and capacitor C2 by 223, has predetermined pulse width to generate
First control signal Vc1.The first end of capacitor C2 is connected to the reversed-phase output with door 222, generates the first control in second end
Signal Vc1.The first end of resistance R2 is connected to the second end of capacitor C2, and the second end of resistance R2 is connected to the ground.Pulse generates
Circuit 223 further includes that the second diode D2 for clamping to first control signal Vc1 makes it only export positive pulse.Ying Li
Solution, the resistance value of resistance R2 and the capacitance of capacitor C2 can be selected as predetermined value, to provide first with predetermined pulse width
Control signal Vc1.It should be understood that one-shot circuit uses differential circuit to provide with predetermined pulse width in the present embodiment
One control signal Vc1, other circuit structures that can be realized above-mentioned function are used equally in the present embodiment.
With reference to Fig. 3, it show the circuit diagram of reference signal generation circuit according to an embodiment of the present invention.Reference signal generates
Circuit 30 includes the second logic circuit 31, voltage generation circuit 32 and detection circuit 33.Detection circuit 33 receives the soft benchmark that opens and believes
Number SS completes signal SS_done by comparing the soft size for opening reference signal SS and setting value V1 to generate soft open.Second patrols
It collects circuit 31 and receives first control signal Vc1, second control signal Vc2 and soft open complete signal SS_done, multiple to generate benchmark
Position signal SS_rst.Voltage generation circuit 32 opens reference signal SS according to the generation of the state of baseline restoration signal SS_rst is soft.
Specifically, the second logic circuit 31 includes and door 311 and/or door 312.It include receiving soft open to complete signal with door 311
The first input end of SS_done and the second input terminal for receiving second control signal Vc2.With the output signal of door 311 and first
Control signal Vc1 is input to or door 312, when it is soft open complete signal SS_done and second control signal Vc2 effective when, or
When first control signal Vc1 is effective or door 312 generates the baseline restoration signal SS_rst of effective status.
Voltage generation circuit 32 includes the controllable switch K1 being connected in parallel between node N and ground, capacitor C3 and current source
I1, generation is soft at node N opens reference signal SS.Current source I1 includes the negative terminal for being connected to node N and the anode of ground connection.Controllably
Switch K1 is controlled by baseline restoration signal SS_rst and carries out turn-on and turn-off, when baseline restoration signal SS_rst is effective high level
When, controllable switch K1 conducting, capacitor C3 and current source I1 are short-circuit, and the soft reference signal SS that opens is pulled low to zero, so that switch change-over
Device stops working；When baseline restoration signal SS_rst is low level, controllable switch K1 shutdown, current source I1 is filled to capacitor C3
Electricity, so that the soft reference signal SS that opens generated at node N starts from scratch rising.Voltage generation circuit 32 further includes being connected to node
Diode D3 between N and input voltage VIN soft opens reference signal SS for clamping.
Detection circuit 33 includes comparator 331 and rest-set flip-flop 332.The first input end of comparator 331 is (for example, same phase
Input terminal) receive it is soft open reference signal SS, the second input terminal (for example, inverting input terminal) receives predetermined value V1, opens benchmark when soft
Signal SS rises to predetermined value V1, and comparator 331 exports soft open and completes signal SS_done.Rest-set flip-flop 322 includes receiving soft open
The set end of signal SS_done is completed, the reset terminal of first control signal Vc1 is received, when soft open completes signal SS_done as height
When level is effective, rest-set flip-flop 332 generates the start completion signal SS_OK of high level, and output voltage detecting circuit starts at this time
Work avoids in switch converters starting, short-circuit protection circuit control switch when feedback signal FB is lower than reference signal Vref
Converter enters short circuit protection mode；When first control signal Vc1 jump is effective status, start completion signal SS_OK quilt
It is reset to low level, until the soft reference signal SS that opens rises to predetermined value V1, rest-set flip-flop 322 generates start completion signal again
SS_OK。
With reference to Fig. 4, it show the circuit diagram of control circuit according to an embodiment of the present invention.Control circuit includes d type flip flop
40.D type flip flop 40 includes the input end of clock CLK, input terminal D interconnected and reverse phase for receiving baseline restoration signal SS_rst
Output endWith receive first control signal clear input CLR, with output end Q generate driving signal Vd.D type flip flop
40 generate the driving signal Vd with the first level and second electrical level by baseline restoration signal SS_rst triggering.In short-circuit condition,
It opens reference signal SS when soft and rises to predetermined value V1 by above freezing, generate effective soft opens and complete signal SS_done.Completion letter is opened when soft
When number SS_done and second control signal Vc2 effective, baseline restoration signal SS_rst has effective short pulse, triggering D triggering
Device 40 generates driving signal Vd, while baseline restoration signal SS_rst control reference signal generation circuit opens reference signal SS for soft
Be pulled low to zero, thus the period of baseline restoration signal SS_rst be equal to it is soft open reference signal SS by it is above freezing rise to predetermined value V1 when
Between.Driving signal Vd periodically switches between the first level and second electrical level with baseline restoration signal SS_rst.Work as drive
When dynamic signal Vd is second electrical level, switch converters start switch operation, so that output voltage is begun to ramp up, access switch shape
State；When driving signal Vd is switched to the first level by second electrical level, switch converters shutdown switch movement, so that output voltage
Zero is remained, into dormant state, is circuited sequentially, until short trouble releases.When short trouble releases, feedback signal FB rises
To reference signal Vref, first control signal Vc1 jump is effective status and is kept for the predetermined time that d type flip flop 40 is according to first
It controls signal Vc1 and driving signal Vd is maintained at the first level, switch converters stop working.Terminate in the predetermined time
Afterwards, the soft reference signal SS that opens starts from scratch rising, and switch converters are started to work.
With reference to Fig. 5, it show the switch converters of the embodiment of the present invention.Switch converters 50 include power stage circuit 51,
Sample circuit 52, error circuit 53, driving circuit 54 and short-circuit protection circuit 55.In the present embodiment, power stage circuit 51 is drop
Die mould topology, it should be understood that can be using various existing switch converters topologys, such as booster type topology, buck-boost type topology
Deng.
Power stage circuit 51 is for receiving input voltage vin and generating output voltage Vout to drive load.Power stage electricity
Road 51 includes inductance L, transistor Q1 and Q2, filter capacitor Co and load Ro.Sample circuit 52 includes the resistance R being connected in seriesH
And RL, for being sampled to output voltage Vout to generate feedback signal FB.The first input end of error circuit 53 is (such as anti-
To input terminal) feedback signal FB is received, the second input terminal (such as non-inverting input terminal) receives reference voltage ref or soft and opens benchmark letter
Number SS, to export the thermal compensation signal VC of characterization output voltage Vout and desired output voltage difference.Switch converters were starting
In journey and when short-circuit condition, the reception of 53 second input terminal of error circuit is soft to open reference signal SS.When switch converters work normally
When, the input signal of 53 second input terminal of error circuit switches to reference voltage ref by the soft reference signal SS that opens.Driving circuit 54
Control signal D is generated to adjust the working time of transistor Q1 and Q2 according to thermal compensation signal VC and clock signal clk, so that output
Voltage Vout is constant in desired output voltage value.
When short trouble occurs, short circuit fault signal ST control switch K2 conducting, output voltage Vout decline, feedback letter
Number FB drops to less than reference signal Vref, and short-circuit protection circuit 55 generates the driving signal with the first level and second electrical level
Vd.Driving circuit 54 receives driving signal Vd, thermal compensation signal VC and clock signal clk to control the work shape of transistor Q1 and Q2
State.When driving signal Vd is the first level state, driving circuit 54 turns off transistor Q1 and Q2, so that inductive current ILIt is zero.
When driving signal Vd is second electrical level state, short-circuit protection circuit 55, which generates, soft to be opened reference signal SS and is input to error circuit
53 normal phase input end, error circuit 53 generate thermal compensation signal VC.Driving circuit 54 is according to thermal compensation signal VC and clock signal clk
Control signal D is generated to adjust the working time of transistor Q1 and Q2, so that switch converters are started to work, is recycled with this, directly
It is released to short trouble.It should be understood that by output voltage when switch K2 and short circuit fault signal ST occurs for equivalent short trouble
It reduces, in practical application when short trouble occurs, such as since load short circuits cause output voltage to reduce, or due to switch
Converter internal performance reduces, cause output voltage drop low etc..
When short trouble releases, short circuit fault signal ST turns off switch K2, and output voltage Vout is begun to ramp up, and works as feedback letter
Reference signal Vref number is risen to, the first control signal Vc1 that short-circuit protection circuit 55 generates effective status simultaneously keeps pre- timing
Between, driving signal Vd is maintained at the first level.Within the predetermined time, the soft reference signal SS that opens keeps being pulled low to zero, so that
Switch converters stop working.In order to by the inductive current I of switch convertersLIt is pulled low to zero, first control signal Vc1 control is opened
K3 conducting is closed, while thermal compensation signal VC holding is pulled low to zero.Terminate when the predetermined time, short-circuit protection circuit 55 generate from
Zero begin to ramp up it is soft open reference signal SS, the normal phase input end of error circuit 53, which receives, soft opens reference signal SS, driving circuit
54 start to start according to thermal compensation signal VC and clock signal clk control switch converter.After start completion, error circuit 53 it is same
Phase input terminal receives reference voltage ref, to export the thermal compensation signal VC of characterization output voltage Vout and desired output voltage difference.
With reference to Fig. 6, it show the working waveform figure of short-circuit protection circuit according to an embodiment of the present invention.
In t0Short trouble occurs for moment, switch converters, and output voltage is pulled low to zero by short circuit fault signal ST, so that
Feedback signal FB is reduced, and thermal compensation signal VC is increased, inductive current ILIncrease.
In t0~t1Period, feedback signal FB are lower than reference signal Vref, and output voltage detecting circuit passes through delay time △
t(t1-t0) effective second control signal Vc2 is generated, short-circuit protection circuit control switch converter enters short circuit protection mode.
In t1Moment, the soft reference signal SS that opens that reference signal generation circuit generates reach predetermined value V1, generate effective
Soft open completes signal SS_done, while exporting effective short pulse baseline restoration signal SS_rst.Reference voltage generating circuit according to
The soft reference signal SS that opens is pulled low to zero by baseline restoration signal SS_rst, then rising of starting from scratch.Control circuit is multiple according to benchmark
Position signal SS_rst generates the driving signal Vd with the first level.The movement of driving signal Vd control switch converter shutdown switch
Into dormant state, inductive current ILRemain zero.
In t2Moment, the soft reference signal SS that opens rise to predetermined value V1, and reference signal generation circuit generates effectively short again
Pulse reference reset signal SS_rst, driving signal Vd switch to second electrical level by the first level, and control switch converter starts
Switch motion access switch state, inductive current ILRise.Until t3Moment, switch state terminate to be again introduced into dormant state, with
This circulation.
In t4Moment, short trouble release, and short circuit fault signal ST is switched to low level by high level.In t5Moment, feedback
Signal FB rises to reference signal Vref, and output voltage detecting circuit generates the first control signal Vc1 of effective status and maintains
Predetermined time △ t1 (t6-t5), driving signal Vd is maintained at the first level.In predetermined time △ t1 initial time (namely t5When
Carve), reference signal generation circuit opens reference signal SS and is pulled low to zero from current value according to first control signal Vc1 by soft, simultaneously
Thermal compensation signal VC holding is pulled low to zero, so that switch converters stop working, inductive current ILHolding is pulled low to zero.
In t6At the moment, predetermined time △, t1 terminated, and short-circuit protection circuit control switch converter exits short circuit protection mode,
The soft reference signal SS that opens starts from scratch rising, and switch converters are started to work, and feedback signal FB starts slowly to rise, while inductance
Electric current is also begun to ramp up.
The technical solution of the embodiment of the present invention is by the way that in the short trouble releasing of switch converters, reference signal generates electricity
The soft reference signal that opens is pulled low to zero from current value and is kept for the predetermined time by road according to first control signal, while the first control letter
Number the thermal compensation signal for characterizing switch converters output voltage and desired output voltage difference is kept into drawing within the predetermined time
Down to zero, so that switch converters stop working, terminate when the predetermined time, the soft reference signal that opens is started from scratch rising, and switch becomes
Parallel operation follows the soft reference signal that opens to start to work, so that output voltage slowly rises, it is ensured that open when short trouble releases
Converter is closed safely and reliably to work.
The above description is only a preferred embodiment of the present invention, is not intended to restrict the invention, for those skilled in the art
For, the invention can have various changes and changes.All any modifications made within the spirit and principles of the present invention are equal
Replacement, improvement etc., should all be included in the protection scope of the present invention.
Claims (16)
1. a kind of short-circuit protection circuit for switch converters, comprising:
Output voltage detecting circuit, for receiving the feedback signal of characterization output voltage, and by the feedback signal and with reference to letter
Number compare, generates first control signal；
Reference signal generation circuit for receiving the first control signal, and generates and soft opens reference signal；
Wherein, at the time of the feedback signal rises to the reference signal, the first control signal jump is effective shape
State is simultaneously kept for a predetermined time, to keep dragging down the soft reference signal that opens to zero, so that described open within the predetermined time
Converter is closed to stop working.
2. short-circuit protection circuit according to claim 1, which is characterized in that the predetermined time initial time by institute
State it is soft open reference signal and be pulled down to zero from current value, at the end of the predetermined time, the soft reference signal that opens is started from scratch
Slowly rise, while the switch converters are started to work, wherein the current value is greater than zero.
3. short-circuit protection circuit according to claim 1, which is characterized in that the short-circuit protection circuit is in the pre- timing
In thermal compensation signal holding is pulled low to zero simultaneously, to drag down the inductive currents of the switch converters to zero, wherein the benefit
Repay the difference of output voltage described in characterization Yu desired output voltage.
4. according to right to go 1 described in short-circuit protection circuit, which is characterized in that when the feedback signal be less than it is described with reference to letter
Number when, and when it is described it is soft open reference signal and rise to predetermined value when, the output voltage detecting circuit generates the of effective status
Two control signals, the reference signal generation circuit generates baseline restoration signal according to the second control signal, to control
It states switch converters and enters short circuit protection mode.
5. short-circuit protection circuit according to claim 4, which is characterized in that the short-circuit protection circuit further includes a control
Circuit, to receive the baseline restoration signal and the first control signal to generate driving signal；
When the second control signal is effective status, the switch converters exist according to the driving signal and clock signal
Switch between dormant state and switch state, when the first control signal is effective status, the switch converters stop
Work.
6. short-circuit protection circuit according to claim 1, which is characterized in that the output voltage detecting circuit includes:
Comparison circuit is used for the feedback signal and reference signal, generates short-circuit signal；
First logic circuit is connect with the output end of the comparison circuit, for that will pass through short-circuit signal and the institute of delay process
It states short-circuit signal and carries out logical operation to generate the first control signal.
7. short-circuit protection circuit according to claim 6, which is characterized in that first logic circuit, which also receives, have been started
Make logical operation at signal, and with the short-circuit signal and by the short-circuit signal of delay process to generate second control signal,
Described in start completion signal for characterizing the switch converters complete start-up course.
8. short-circuit protection circuit according to claim 7, which is characterized in that first logic circuit includes:
Delay circuit, for postponing the short-circuit signal with predetermined delay time；
With door comprising the first input end being connect with the output end of the delay circuit, the output end with the comparison circuit
The second input terminal for being used to receive the short-circuit signal of connection, receives the third input terminal of the start completion signal, generates
The in-phase output end and reversed-phase output of the second control signal；
Pulse generation circuit is connect with described with the reversed-phase output of door to generate the first control signal.
9. short-circuit protection circuit according to claim 8, which is characterized in that the delay circuit includes:
First resistor, first end are connected to the output end of the comparison circuit, and second end is connected to described first defeated with door
Enter end；
First capacitor, first end are connected to the second end of the first resistor, second end ground connection.
10. short-circuit protection circuit according to claim 8, which is characterized in that the one-shot circuit includes:
Second capacitor, first end are connected to the reversed-phase output with door, and second end exports the first control signal；
Second resistance, first end are connected to the second end of second capacitor, second end ground connection.
11. short-circuit protection circuit according to claim 7, which is characterized in that the reference signal generation circuit includes:
Detection circuit, for detect it is described it is soft open reference signal, when the soft reference signal that opens rises to predetermined value, generate soft opens
Complete signal；
Second logic circuit completes signal for receiving soft open, and first control signal and second control signal simultaneously make logic
Operation, to generate baseline restoration signal；
Voltage generation circuit, for being pulled low to the soft reference signal that opens in the effective status of the baseline restoration signal
Zero, the soft reference signal that opens is controlled in the invalid state of the baseline restoration signal from liter above freezing.
12. short-circuit protection circuit according to claim 11, which is characterized in that when the first control signal is effective shape
When state, the baseline restoration signal remains effective status simultaneously within the predetermined time, generates electricity to control the voltage
Road keeps the soft reference signal that opens to be pulled low to zero.
13. short-circuit protection circuit according to claim 5, which is characterized in that the control circuit includes a trigger, institute
Baseline restoration signal described in the clock input of trigger is stated, input terminal is connect with in-phase output end, and clear input connects
The first control signal is received, the driving signal with the first level and second electrical level is generated in in-phase output end；
Wherein, when the second control signal is effective status, when the driving signal is the first level, the switching mode becomes
Parallel operation work is in the dormant state, and when the driving signal is second electrical level, the switched mode converter work is opened described
Off status.
14. short-circuit protection circuit according to claim 13, which is characterized in that when the first control signal is effective shape
When state, the driving signal is maintained at the first level state, and the switch converters stop working.
15. a kind of switch converters, which is characterized in that including any short-circuit protection circuit described in claim 1-14, also wrap
It includes:
Sample circuit is connect to generate the feedback signal of the characterization output voltage with the output end of the switch converters；
Error circuit, according to the feedback signal, soft reference signal and the reference voltage of opening generates the thermal compensation signal；
Driving circuit, according to the thermal compensation signal, the driving signal and clock signal of the short-circuit protection circuit output control institute
State the working condition of switch converters.
16. switch converters according to claim 15, which is characterized in that the switch converters further include first opening
It closes, the first switch is connected to the output end of the error circuit；When the first control signal is effective, described first is opened
It closes and closes, thermal compensation signal holding is pulled low to zero.
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| CN201810919834.0A CN109274073B (en) | 2018-08-14 | 2018-08-14 | Short-circuit protection circuit and switch converter using same |
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| CN201810919834.0A CN109274073B (en) | 2018-08-14 | 2018-08-14 | Short-circuit protection circuit and switch converter using same |
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| CN109274073B CN109274073B (en) | 2020-10-16 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111711170A (en) * | 2020-07-07 | 2020-09-25 | 成都芯源***有限公司 | Short-circuit protection circuit and method for switching power supply |
| CN112533324A (en) * | 2020-12-17 | 2021-03-19 | 矽力杰半导体技术(杭州)有限公司 | Control circuit based on soft start and LED drive circuit applying same |
| CN114072999A (en) * | 2020-06-09 | 2022-02-18 | 华为数字能源技术有限公司 | Voltage reduction circuit, voltage reduction device and circuit control method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101727124A (en) * | 2008-10-22 | 2010-06-09 | 登丰微电子股份有限公司 | Soft start circuit |
| CN101807905A (en) * | 2010-02-11 | 2010-08-18 | 西安能讯微电子有限公司 | Drive circuit of deplete semiconductor switching element and drive method thereof |
| CN103280962A (en) * | 2013-06-20 | 2013-09-04 | 帝奥微电子有限公司 | Short circuit recovery soft starting circuit |
| CN104201875A (en) * | 2014-08-07 | 2014-12-10 | 矽力杰半导体技术(杭州)有限公司 | Short circuit protection soft start circuit and method |
| US9985543B1 (en) * | 2017-04-07 | 2018-05-29 | Suzhou Poweron Ic Design Co., Ltd. | Switching power supply |
-
2018
- 2018-08-14 CN CN201810919834.0A patent/CN109274073B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101727124A (en) * | 2008-10-22 | 2010-06-09 | 登丰微电子股份有限公司 | Soft start circuit |
| CN101807905A (en) * | 2010-02-11 | 2010-08-18 | 西安能讯微电子有限公司 | Drive circuit of deplete semiconductor switching element and drive method thereof |
| CN103280962A (en) * | 2013-06-20 | 2013-09-04 | 帝奥微电子有限公司 | Short circuit recovery soft starting circuit |
| CN104201875A (en) * | 2014-08-07 | 2014-12-10 | 矽力杰半导体技术(杭州)有限公司 | Short circuit protection soft start circuit and method |
| US9985543B1 (en) * | 2017-04-07 | 2018-05-29 | Suzhou Poweron Ic Design Co., Ltd. | Switching power supply |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114072999A (en) * | 2020-06-09 | 2022-02-18 | 华为数字能源技术有限公司 | Voltage reduction circuit, voltage reduction device and circuit control method |
| CN111711170A (en) * | 2020-07-07 | 2020-09-25 | 成都芯源***有限公司 | Short-circuit protection circuit and method for switching power supply |
| CN112533324A (en) * | 2020-12-17 | 2021-03-19 | 矽力杰半导体技术(杭州)有限公司 | Control circuit based on soft start and LED drive circuit applying same |
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|---|---|
| CN109274073B (en) | 2020-10-16 |
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