CN104466912B - A kind of linear voltage regulator with short-circuit protection - Google Patents
A kind of linear voltage regulator with short-circuit protection Download PDFInfo
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- CN104466912B CN104466912B CN201410706834.4A CN201410706834A CN104466912B CN 104466912 B CN104466912 B CN 104466912B CN 201410706834 A CN201410706834 A CN 201410706834A CN 104466912 B CN104466912 B CN 104466912B
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Abstract
The invention provides a kind of linear voltage regulator with short-circuit protection, including adjustment pipe, output voltage controlling circuit, short-circuit decision circuitry and short-circuit protection circuit, in addition to current-limiting circuit.During the linear voltage regulator normal work, the value of output voltage is controlled to be maintained the value of desired output voltage by output voltage controlling circuit, and during short circuit, being turned off for adjustment pipe batch (-type) is controlled by short-circuit protection circuit, by the current limit that adjustment pipe is flowed through during short circuit it is the electric current during less than normal work by current-limiting circuit, the effective power attenuation for reducing adjustment pipe during short circuit, it is not in the phenomenon of overheat, the thermal protection module in system so as to which the integrated linear voltage regulator will not be triggered, the normal work of whole system is not interfered with thus.
Description
Technical field
The present invention relates to field of power electronics, in particular, it is related to a kind of linear voltage regulator with short-circuit protection.
Background technology
Linear voltage regulator (such as linear voltage regulator, low dropout regulator, abbreviation LDO) due into
The advantages of this low, noise is small, quiescent current is small, and be widely used in the application systems such as power management.It is linear being integrated with
In the power management chip of voltage-stablizer, because linear voltage regulator will be provided than larger electric current, when output short-circuit, linear voltage stabilization
The output end of device is directly grounded, and excessive electric current flows through the adjustment pipe of linear voltage regulator, may cause whole power management chip
Damage, therefore generally also needed to short-circuit protection circuit in linear voltage regulator, it is linear steady to prevent from causing during load short circuits
The damage of depressor and power management chip.
In the prior art, the short-circuit protection method of conventional linear voltage regulator is：Detecting the output of linear voltage regulator
When voltage is less than certain value, by the short circuit limitation electric current that output current is limited to less than or equal to one value is relatively low, so as to avoid
The electric current for flowing through adjustment pipe is excessive and causes to adjust pipe and burns out, and realizes the short-circuit protection to linear voltage regulator.Using existing
During short-circuit protection of this short-circuit protection method of technology to realize linear voltage regulator, adjustment pipe is constantly in conducting state, short circuit
When adjustment pipe on power attenuation for linear voltage regulator input voltage and output voltage difference with limitation electric current product.By
When short circuit, the output voltage of linear voltage regulator is generally than relatively low, and short circuit limitation electric current can not set as far as possible low (too low
Meet start when, easily cause false triggering), therefore short-circuit dissipation during short circuit on adjustment pipe is still than larger, especially
When input voltage is larger, short-circuit dissipation can be bigger.Excessive short-circuit dissipation easily causes the temperature liter in power management chip
Height, when temperature is raised to certain value, may trigger the thermal protection module inside power management chip, and by whole power management
Each road circuit of chip is turned off.
It can be seen that, the short-circuit protection of linear voltage regulator is realized using this short-circuit protection method of prior art, can be caused short
Lu Shi, the loss for adjusting pipe is larger, and the easily thermal protection module of triggering system during short circuit for a long time, and influences whole system just
Often operation.
The content of the invention
In view of this, the invention provides a kind of linear voltage regulator with short-circuit protection, to solve to exist in the prior art
When realizing the short-circuit protection of linear voltage regulator, the problem of system is normally run easily is influenceed because short-circuit dissipation is larger.
A kind of linear voltage regulator with short-circuit protection, including adjustment pipe, output voltage controlling circuit, short-circuit decision circuitry
And short-circuit protection circuit；
The adjustment pipe is connected between the direct-flow input end of the linear voltage regulator and output end of pressure-stabilizing, the output electricity
Voltage-controlled circuit processed is used for the error signal for exporting the difference of the desired output voltage for characterizing the linear voltage regulator and output voltage,
To control the pressure drop of the adjustment pipe, the value of the current output voltage is set to be maintained the value of the desired output voltage；
The short-circuit decision circuitry is used to generate short-circuit indication signal according to the size of the current output voltage, when described
When current output voltage is less than or equal to short-circuit threshold value voltage, the short-circuit indication signal is effective status；
The short-circuit protection circuit is used to control the adjustment pipe batch (-type) during the indication signal is effective status
Shut-off.
It is preferred that, described linear voltage regulator also includes output voltage feedback circuit, for generating the current output electricity
The feedback voltage of pressure.
It is preferred that, the short-circuit decision circuitry includes first comparator,
The first input end of the first comparator receives the feedback voltage, and the second input, which is received, characterizes the short circuit
Second reference voltage signal of threshold voltage, output end exports the short-circuit indication signal.
It is preferred that, described linear voltage regulator also includes buffering drive circuit, and the buffering drive circuit is connected to described
Between the output end of output voltage controlling circuit and the control end of the adjustment pipe.
It is preferred that, the output voltage controlling circuit includes the first error amplifier；
The first input end of first error amplifier receives a first benchmark electricity for characterizing the desired output voltage
Pressure, the second input receives the feedback voltage, and output end exports the error signal.
It is preferred that, the short-circuit protection circuit is connected to the output end of the short-circuit decision circuitry and the output voltage control
Between the output end of circuit processed,
During the short-circuit indication signal is effective status, the short-circuit protection circuit batch (-type) believes the error
Number zero is reduced to, so that the shut-off of the adjustment pipe batch (-type).
It is preferred that, the short-circuit protection circuit includes first control circuit and first switch；
The first switch is connected between the output and ground of the output voltage controlling circuit；
The first control circuit receives the short-circuit indication signal, is the disarmed state phase in the short-circuit indication signal
Between, control the first switch to turn off always, during the short-circuit indication signal is effective status, control the first switch
Turn off, turned in second time period in first time period；
Alternately occur during the effective status of the first time period and second time period for the short-circuit indication signal
Two periods.
It is preferred that, the first control circuit includes the first pulse-generating circuit, the second pulse-generating circuit, the 3rd pulse
Generation circuit, the first timer, the second timer, the first OR gate, first and door and rest-set flip-flop；
The input of first pulse-generating circuit receives the short-circuit indication signal, and output end is connected to described first
The first input end of OR gate, the second input, the reset terminal of the rest-set flip-flop and second meter of first OR gate
When device output end of the reset terminal with the 3rd pulse-generating circuit be connected；
Described first receives the output of the short-circuit indication signal and first OR gate with two inputs of door respectively
Signal, output end is connected to the input end of first timer；
The output end of first timer is connected with the set end of the rest-set flip-flop, the output end of the rest-set flip-flop
Export the control signal for controlling the first switch turn-on and turn-off；
The input of second pulse-generating circuit receives the control signal, output end respectively with first timing
The reset terminal of device, the input end of second timer are connected, and the output end of second timer is produced with the 3rd pulse
The input of raw circuit is connected.
It is preferred that, described linear voltage regulator also includes current-limiting circuit,
When the short-circuit indication signal is disarmed state, the electric current that the adjustment pipe is flowed through in the current-limiting circuit control is small
In or equal to first limitation electric current,
When the short-circuit indication signal is effective status, the electric current that the adjustment pipe is flowed through in the current-limiting circuit control is small
In or equal to second limitation electric current,
The second limitation electric current is less than the described first limitation electric current.
It is preferred that, the current-limiting circuit include current sampling circuit, current limliting benchmark generative circuit, the second error amplifier and
Diode；
The current detection circuit is used to obtain the sampled voltage for characterizing and flowing through the adjustment tube current；
The current limliting benchmark generative circuit is when the short-circuit indication signal is disarmed state, and output characterizes first limit
3rd reference voltage of electric current processed, when the short-circuit indication signal is effective status, output table characterizes second and limits electric current
4th reference voltage, the 4th reference voltage is less than the 3rd reference voltage；
The first input end of second error amplifier is connected with the output end of the current sampling circuit, the second input
End is connected with the current limliting benchmark generative circuit, and output end is connected with the negative electrode of the diode；
The anode of the diode is connected with the output end of the output voltage controlling circuit.
Have upper visible, the linear voltage regulator with short-circuit protection disclosed in the embodiment of the present application, during normal operation
The value for controlling output voltage by output voltage controlling circuit is maintained the value of desired output voltage, and during short circuit, passes through
Being turned off for short-circuit protection circuit control adjustment pipe batch (-type), it is effective to reduce the power attenuation for adjusting pipe during short circuit, no
The phenomenon of overheat occurs, so that the thermal protection module during the system of the integrated linear voltage regulator will not be triggered, thus will not shadow
Ring the normal work of whole system.And during short circuit, by current-limiting circuit will flow through adjustment pipe current limit for one compared with
Small electric current, further reduces the power attenuation of adjustment pipe so that the linear voltage regulator can be realized certainly during short circuit
The protection of body, but not in its integrated system other circuits normal work.
Brief description of the drawings
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
There is the accompanying drawing used required in technology description to be briefly described, it should be apparent that, drawings in the following description are only this
The embodiment of invention, for those of ordinary skill in the art, on the premise of not paying creative work, can also basis
The accompanying drawing of offer obtains other accompanying drawings.
Fig. 1 is a kind of structure chart of the linear voltage regulator with short-circuit protection disclosed in the embodiment of the present application；
Fig. 2 is a kind of circuit diagram of optional mode of the linear voltage regulator with short-circuit protection shown in Fig. 1；
Fig. 3 is the working waveform figure of the linear voltage regulator with short-circuit protection shown in Fig. 2；
Fig. 4 be Fig. 2 shown in linear voltage regulator in first control circuit another optional implementation circuit diagram；
Fig. 5 is the working waveform figure of the first control circuit shown in Fig. 4.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear
Fig. 1 is a kind of structure chart of the linear voltage regulator with short-circuit protection disclosed in the embodiment of the present application.
With reference to Fig. 1, the disclosed linear voltage regulator 100 with short-circuit protection of the embodiment of the present application include an adjustment pipe 01,
Output voltage controlling circuit 02, short-circuit decision circuitry 03 and short-circuit protection circuit 04, the linear voltage regulator are generally low voltage difference
Linear voltage regulator.Wherein, adjustment pipe is connected to direct-flow input end (the reception input voltage V of linear voltage regulator 100INOne end) and
Output end of pressure-stabilizing (output current output voltage VOUTOne end) between.Adjustment pipe 01 can with but be not limited to P as shown in Figure 1
Type metal oxide semiconductor field-effect transistor (MOSFET) M1, can also be N-type MOSFET or other types of transistors,
Adjustment pipe 01 will be used as using the MOSFET of p-type in various embodiments of the present invention.Output voltage controlling circuit 02, which is used to export, to be characterized
Desired output voltage (voltage swing is general to be determined according to load) and the current output voltage V of linear voltage regulator 100OUT(i.e. line
The voltage of the property reality output of voltage-stablizer 100) difference error signal, with during the normal work of linear voltage regulator 100
The pressure drop of (the short-circuit indication signal SHORT invalid periods of i.e. short-circuit decision circuitry output) control adjustment pipe 01, so as to finally make
Current output voltage VOUTValue be maintained the value of the desired output voltage.That is, linear voltage regulator 100 is in non-short
During road, as expectation output voltage and current output voltage VOUTDuring difference increase, the increase of the error signal manages adjustment
01 pressure drop reduces, so that current output voltage VOUTRise, to reduce desired output voltage and current output voltage VOUTDifference
Value, if on the contrary, current output voltage VOUTValue exceed desired output voltage, then control adjustment pipe 01 pressure drop increase so that
Make current output voltage VOUTReduction, so that current output voltage VOUTReduce with the difference of desired output voltage, it is final to realize control
Current output voltage V processedOUTValue be maintained the value of the desired output voltage.
Short-circuit decision circuitry 03 is used for according to current output voltage VOUTThe short-circuit indication signal SHORT of size generation, work as line
When there is short circuit in property voltage-stablizer 100, current output voltage VOUTDrop below or equal to short-circuit threshold value voltage, short circuit is indicated
Signal SHORT is effective status.In the present embodiment and subsequent embodiment the effective status of signal can with but be not limited to high electricity
Flat, in other alternative embodiments, effective status can also refer to low level state.
Short-circuit protection circuit 04 is used between control adjustment pipe 01 during the short-circuit indication signal SHORT is effective status
The shut-off for formula of having a rest.Short-circuit protection circuit 04 is attached between decision circuitry 03 and the output end of output voltage controlling circuit.
During short-circuit indication signal SHORT is effective status, the batch (-type) of short-circuit protection circuit 04 by output voltage controlling circuit 02
The error signal of output was reduced to for zero a period of time, so that adjustment pipe 01 can be turned off within the period, adjustment pipe 01 exists
Not by the control of output voltage controlling circuit 02 in the period.During the short circuiting work pattern of voltage-stablizer 100, short-circuit protection
Circuit 04 is turned off every a period of time control adjustment pipe 01, and turn-on and turn-off replace priority to adjustment pipe 01 during this period,
Rather than conducting state is constantly in, the power attenuation on pipe 01 is adjusted during effectively reducing short circuit so that adjustment pipe 01
It is difficult to be damaged, and avoids whole caused by the thermal protection module of adjustment pipe 01 system that the integrated voltage-stablizer is triggered because of overheat
The problem of system can not normally be run.
The disclosed linear voltage regulator 100 with short-circuit protection of the present embodiment also includes output voltage feedback circuit
05, it is used to generate current output voltage VOUTFeedback voltage.Output voltage controlling circuit 02 and short-circuit decision circuitry 03 can
The feedback voltage is received respectively, to generate the error signal and short-circuit indication signal SHORT, so only needs to control feedback electricity
Pressure and the proportionate relationship of output voltage, just can realize the regulation to different output voltages.
The disclosed linear voltage regulator 100 with short-circuit protection of the present embodiment also includes buffering drive circuit 06, its
It is connected between the output end 02 of output voltage controlling circuit and the control end for adjusting pipe 01, for receiving output voltage control electricity
The error signal that road 02 is generated, and the control signal of output adjustment pipe 01, to control the pressure drop for adjusting pipe 01.Buffering drive circuit
06 can quickly increase or decrease the driving current of adjustment pipe, can effectively improve response speed of the linear voltage regulator to load change
Degree.
The disclosed linear voltage regulator 100 with short-circuit protection of the present embodiment also includes current-limiting circuit 07, and it is used for
The output current of linear voltage regulator 100 is limited according to short-circuit indication signal.It it is the disarmed state phase in short-circuit indication signal SHORT
Between, linear voltage regulator 100 is in normal operating conditions, if output current is less than or equal to the first limitation electric current, cut-off current 07
The size of output current is not controlled, i.e., the control for exchanging homogeneous tube 01 during this period does not work.In output current once more than the
During one limitation electric current, current-limiting circuit 07 starts to limit output current, and it can drag down the error of the output of output voltage controlling circuit 02
The value of signal, to control the pressure drop of adjustment pipe 01 to reduce, and then is reduced to the first limitation electric current or the first limitation electricity by output current
Within stream, it is to avoid operationally, adjustment pipe 01 is because of the electric current born is excessive and damages phenomenon for linear voltage regulator 100.First limit
The value of electric current processed be generally located on adjustment the trouble free service electric current of pipe 01 value and the full load of linear voltage regulator 100 output current it
Between.During short-circuit indication signal SHORT is effective status, the electric current of the controlling stream toning homogeneous tube of current-limiting circuit 07 is less than or equal to
Second limitation electric current, what the second limitation electric current was set is less than the first limitation electric current.Therefore during the short circuit of linear voltage regulator 100,
Flow through adjustment pipe 01 electric current for one be less than normal work when electric current, so as to further reduce short circuit during, adjustment pipe
Power attenuation on 01, it is to avoid it triggers the thermal protection module of system and influences the normal work of whole system.
Therefore, the linear voltage regulator with short-circuit protection disclosed in the embodiment of the present application, during normal operation
The value of current output voltage is controlled to be maintained the value of desired output voltage by output voltage controlling circuit, and during short circuit,
Being turned off for adjustment pipe batch (-type) is controlled by short-circuit protection circuit, the effective power for reducing adjustment pipe during short circuit is damaged
Consumption, is not in the phenomenon of overheat, so that the thermal protection module during the system of the integrated linear voltage regulator will not be triggered, thus not
The normal work of whole system can be influenceed.And during short circuit, the current limit of adjustment pipe will be flowed through to be low by current-limiting circuit
Electric current when normal work, further reduces the power attenuation of adjustment pipe so that the linear voltage regulator is during short circuit
The protection of itself can be realized, and does not influence the normal work of other circuits in integrated system.
Fig. 2 is a kind of circuit diagram of optional mode of the linear voltage regulator with short-circuit protection shown in Fig. 1.
With reference to Fig. 2, output voltage controlling circuit 02 in Fig. 1 is sets forth in the present embodiment, short-circuit decision circuitry 03, short
Road protection circuit 04, output voltage feedback circuit 05, drive circuit 06 and current-limiting circuit 07 implement circuit, but each
The specific implementation of circuit is not limited to mode as shown in Figure 2.
In the present embodiment, adjustment pipe 01 is p-type MOS memory M1, M1Source electrode receive input electricity
Press VIN, drain electrode output current output voltage VOUT.Output voltage feedback circuit 05 is one by resistance R1With resistance R2The electricity of composition
Hinder divider, resistance R1One end and M1Drain electrode be connected, to receive current output voltage VOUT, the other end passes through resistance R2Connect
Ground, resistance R1、R2Output characterizes current output voltage V at connected nodeOUTFeedback voltage VFB.Output voltage controlling circuit
02 includes the first error amplifier EA1, buffering drive circuit be the first phase inverter N1.The EA of first error amplifier1It is same mutually defeated
Enter the first reference voltage V that end receives the desired output voltage for characterizing linear voltage regulator 100REF1, inverting input, which is received, to be fed back
Voltage VFB, output error signal V at output terminals AA, and pass through the first reverser N1It is connected to adjustment pipe M1Grid (control end),
First comparator CP1In-phase input end receive the second benchmark for characterizing short-circuit threshold value voltage described in upper one embodiment
Voltage VREF2, end of oppisite phase reception feedback voltage VFB, output end output short-circuit indication signal SHORT.Current-limiting circuit 07 includes electric current
Sample circuit, the second error amplifier EA2, diode D1And by switching K1, resistance R3、R4The current limliting benchmark generation electricity of composition
Road.Wherein, resistance R3、R4It is connected in series in the 3rd reference voltage VREF3Between earth terminal, K is switched1With resistance R3It is connected in parallel,
And its on off state is controlled by the non-signal of short-circuit indication signal, when short-circuit indication signal is low level (disarmed state), open
Close K1It is constantly on, resistance R3With R4Junction export the 3rd reference voltage VREF3, when short-circuit indication signal is that high level (has
Effect state) when, switch K1Turn off always, resistance R3With R4Junction export the 4th reference voltage VREF4, wherein, VREF4=RREF3
×R3/(R3+R4).Current sampling circuit can be with adjustment pipe M1One end be connected, flow through adjustment pipe M for obtaining sign1Electricity
The sampled voltage V of streamC, i.e. VCWith flowing through M1Current in proportion.The in-phase input end of second error amplifier is connected to resistance R3
With R4Connecting place, to receive the current-limiting points voltage V at thisB(i.e. during short-circuit indication signal disarmed state, receive the 3rd base
Quasi- voltage VREF3, during short-circuit indication signal effective status, receive the 4th reference voltage VREF4), output end and diode D1's
Negative electrode is connected, and the anode of diode is connected to the output end of output voltage controlling circuit 02, i.e. the first error amplifier EA1It is defeated
Go out end.
Short-circuit protection circuit 04 includes first control circuit 04-1 and first switch S1, wherein first switch S1It is connected to
One error amplifier EA1Output end (output end of output voltage controlling circuit 02) between earth terminal, first control circuit
For receiving short-circuit indication signal SHORT, to control first switch S1Switch motion, short-circuit indication signal SHORT be nothing
During effect state, first control circuit control first switch S1Turn off always, be the effective status phase in short-circuit indication signal SHORT
Between, first control circuit 04-1 control first switches S1Turn off, turned in second time period, with batch (-type) in first time period
By error signal VAIt is reduced to zero.First time period and second time period are that short-circuit indication signal SHORT is the effective status phase
Between alternately occur two periods.That is first control circuit control first switch S1Enter during the short circuit of linear voltage regulator 100
Row first conducting a period of time turns off the sampling action of a period of time again.
First control circuit 04-1 includes the first pulse-generating circuit OS in the present embodiment1, the second pulse-generating circuit
OS2, the 3rd pulse-generating circuit OS3, the first timer Tm1, the second timer Tm2, the first OR gate OR1, first with door AND1With
Rest-set flip-flop.First pulse-generating circuit OS1Input receive the short-circuit indication signal SHORT, output end is connected to the
One OR gate OR1First input end, the first OR gate OR1The second input, the reset terminal " S " of rest-set flip-flop and the second timing
Device Tm1Reset terminal with the 3rd pulse-generating circuit OS3Output end be connected.First and door AND1Two inputs difference
Receive short circuit indication signal SHORT and the first OR gate OR1Output signal, output end is connected to the first timer Tm1Defeated people
End.First timer Tm1Output end be connected with the set end " R " of rest-set flip-flop, the output end of rest-set flip-flop is exported for controlling
Make the control signal Q of the first switch turn-on and turn-off2.Second pulse-generating circuit OS2Input receive control signal
Q2, reset terminal, the second timer Tm of output end respectively with the first timer Tm12Input end be connected, the second timer Tm2's
Output end and the 3rd pulse-generating circuit OS3Input be connected.
Fig. 3 is the working waveform figure of the linear voltage regulator shown in Fig. 2.
With reference to Fig. 3, the work sheet according to Fig. 3 is come the course of work of the linear voltage regulator shown in analysis chart 2.In t0Extremely
t1Moment, the feedback voltage V of linear voltage regulatorFBIt is maintained the first reference voltage VREF1Near, current-limiting circuit will flow through adjustment pipe
Electric current (be equal to output current IOUT) it is limited to the first limitation electric current ILIMIT1Or within it, the linear voltage regulator in this stage is in
Normal operating conditions.In t1Short circuit, feedback voltage V occur for moment, the output end of linear voltage regulatorFBIt is reduced to the second benchmark suddenly
Voltage VREF2Or it is following, now short circuit indication signal SHORT is changed into useful signal, current-limiting points voltage VBIt is now the 4th benchmark electricity
Press VREF4, current-limiting circuit, which will flow through, adjusts pipe M1Current limit be the second limitation limitation of electric current first electric current ILIMIT2Or its with
It is interior.First pulse-generating circuit OS1Produce a pulse signal clk1, the signal is through the first OR gate OR1After export still for a pulse believe
Number, because now short-circuit indication signal SHORT is 1 (1 represents high level, and 0 represents low level), then first with door AND1Output
Also it is a pulse signal, the first timer Tm1Start, and timing is to t2Moment, in t2Before moment, the first timer Tm1Output
For 0, rest-set flip-flop output Q1, first switch S1It is held off.Until t2Moment arrives, the first timer Tm1Timing is completed, its
The signal T1 of output is changed into 1, rest-set flip-flop output Q1It is changed into 1, first switch S1Conducting, the first error amplifier EA1Output end
The current potential of A points is pulled to 0, i.e. error signal VAValue be reduced to zero, the first phase inverter N1Output be changed into highest so that adjustment pipe
M1It is turned off.In M1The output voltage and output current of linear voltage regulator are 0 during shut-off, now adjust pipe M1Inactivity is damaged
Consumption.While adjustment pipe is turned off, rest-set flip-flop output Q1For 1, the second pulse-generating circuit OS2Produce a pulse signal
clk2, the second timer Tm of signal triggering2Start working, while also by the first timer Tm1(clearing) is resetted so as to weight next time
New timing.As the second timer Tm2Timer is to t3When, timing is completed, its signal T exported2Become 1, the 3rd pulses generation electricity
Road OS3Export a pulse signal clk3Rest-set flip-flop is resetted, the output signal Q of rest-set flip-flop1It is changed into 0, first switch S1Again
It is turned off, the current potential of A points is no longer pulled low to 0, while the 3rd pulse-generating circuit OS3Output by the second timer Tm2Clearly
Zero.If short-circuit indication signal SHORT is still effective status, i.e., short-circuit indication signal SHORT is 1, then the first timer Tm1Weighed
It is new start and reclocking for a period of time when, first switch K1Turn on again, adjustment pipe M1Again shut-off a period of time, weigh always
This multiple process (shut-off of adjustment pipe batch (-type)) is changed into 0, the first timer Tm until short-circuit indication signal SHORT1It is prohibited,
First switch S1It is turned off always, A points voltage recovers normal operating conditions, circuit recovers normal.
Fig. 4 be Fig. 2 shown in linear voltage regulator in first control circuit another optional implementation circuit diagram.
Include the second phase inverter N with reference to Fig. 4, first control circuit 04-12(NOT gate), the second OR gate OR2, second switch S2、
3rd switch S3, the first electric capacity C1, the second electric capacity C2, the first current source I1, the second current source I2, the second comparator CP2, the 3rd ratio
Compared with device CP3, second with door AND2, the 3rd phase inverter N3, the 4th phase inverter N4And the 4th pulse-generating circuit OS4。
Wherein, N2Receive short-circuit indication signal SHORT, output end and the second OR gate OR2An input be connected, second or
Door OR2Another input receive the 4th pulse-generating circuit OS4Output pulse signal, output end respectively with second switch S2、
3rd switch S3Control end be connected.Second switch S2With the first electric capacity C1It is connected in parallel, the first current source I1Also with the first electric capacity
C1It is connected in parallel, and the first electric capacity C1One end ground connection, the other end is connected to the second comparator CP2Inverting input, with to this
The first electric capacity C of end output1On voltage VD.Second comparator CP2In-phase end receive one the 5th reference voltage VREF5, output end
The signal T of output3It is passed to second and door AND2An input, second with door AND2Another two input connect respectively
Receive short circuit indication signal SHORT and the 3rd comparator CP3Output signal T4, output end passes through the 4th phase inverter N4Output first
Switch S1Switch controlling signal Q1.3rd switch S3With the second electric capacity C2It is connected in parallel, the second current source I2Also with the second electric capacity
C2It is connected in parallel, and the second electric capacity C2One end ground connection, the other end is connected to the 3rd comparator CP3Inverting input, with to this
The second electric capacity C of end output2On voltage VE, the 3rd comparator CP3In-phase end receive the 6th reference voltage VREF6, output end is same
When be connected to the 3rd phase inverter N3Input, the 3rd phase inverter N3Output end and the 4th pulse-generating circuit OS4Input
End is connected.
Fig. 5 is the working waveform figure of the first control circuit shown in Fig. 4.
With reference to Fig. 5, the job control process of the first control circuit 04-1 shown in analysis chart 4.In t0Moment, short circuit is indicated
Signal SHORT is changed into 1, second and door AND2Output signal nd2For 1, then switch controlling signal Q1For 0, first switch S1Close
It is disconnected, adjustment pipe M1Conducting, the second OR gate OR2It is output as 0, second switch S2With the 3rd switch S3It is turned off, the first current source I1With
Second current source I2Respectively to the first electric capacity C1With the second electric capacity C2Charging, voltage VDWith voltage VEBegin to ramp up, until t1Moment,
Voltage VDRise to VREF5, signal T3Saltus step is 0, due to voltage VEDo not rise to V alsoREF6, then now signal T4Still it is 1, signal
nd2Saltus step is 0, Q1Saltus step is 1, first switch S1Begin to turn on, adjustment pipe M1Start to be turned off, until t2Moment, voltage VEOn
It is raised to VREF6, signal T4Saltus step is i.e. third party's phase device N 0 once3Output saltus step be 1, the 4th pulse-generating circuit OS4Touched
Send out and export a pulse signal clk4, the signal makes the second OR gate OR2It is changed into 1, then second switch S2With the 3rd S3It is both turned on,
Voltage VDAnd VEZero, signal T are pulled low to rapidly3Saltus step is 1, signal T4Also 1 is immediately become, then signal nd2It is changed into 1, switch
Control signal Q1It is changed into 0, first switch S1It is turned off, adjustment pipe is by M1Conducting, if next short circuit indication signal SHORT is still
Effectively, then this process is repeated so that first switch S1Alternately turn off and lead in the short-circuit indication signal SHORT valid periods
It is logical, so that adjustment pipe M1In this period by the shut-off of alternate turn-on and turn-off, i.e. batch (-type).Until short-circuit indication signal
During SHORT is changed into 0, second switch S1With the 3rd switch S3It is switched on, switch controlling signal Q1Opened in disarmed state, first
Close S1Turn off always during this period, A points voltage is recovered normal operating conditions, circuit recovers normal.
Have upper visible, the linear voltage regulator with short-circuit protection disclosed in the embodiment of the present application, during normal operation
The value for controlling output voltage by output voltage controlling circuit is maintained the value of desired output voltage, and during short circuit, passes through
Being turned off for short-circuit protection circuit control adjustment pipe batch (-type), it is effective to reduce the power attenuation for adjusting pipe during short circuit, no
The phenomenon of overheat occurs, so that the thermal protection module during the system of the integrated linear voltage regulator will not be triggered, thus will not shadow
Ring the normal work of whole system.And during short circuit, by current-limiting circuit will flow through adjustment pipe current limit for one compared with
Small electric current, further reduces the power attenuation of adjustment pipe so that the linear voltage regulator can be realized certainly during short circuit
The protection of body, but not in its integrated system other circuits normal work.
The embodiment of each in this specification is described by the way of progressive, and what each embodiment was stressed is and other
Between the difference of embodiment, each embodiment same or similar part mutually referring to.
The foregoing description of the disclosed embodiments, enables professional and technical personnel in the field to realize or using the present invention.
A variety of modifications to these embodiments will be apparent for those skilled in the art, as defined herein
General Principle can be realized in other embodiments without departing from the spirit or scope of the present invention.Therefore, it is of the invention
The embodiments shown herein is not intended to be limited to, and is to fit to and principles disclosed herein and features of novelty phase one
The most wide scope caused.
Claims (9)
1. a kind of linear voltage regulator with short-circuit protection, including adjustment pipe, output voltage controlling circuit, short circuit decision circuitry with
And short-circuit protection circuit；
The adjustment pipe is connected between the direct-flow input end of the linear voltage regulator and output end of pressure-stabilizing, the output voltage control
Circuit processed is used for the error signal for exporting the difference of the desired output voltage for characterizing the linear voltage regulator and current output voltage,
Pressure drop to control the adjustment pipe during short-circuit indication signal is disarmed state, maintains the value of the current output voltage
For the value of the desired output voltage；
The short-circuit decision circuitry is used to generate the short-circuit indication signal according to the size of the current output voltage, when described
When current output voltage is less than or equal to short-circuit threshold value voltage, the short-circuit indication signal is effective status；
The short-circuit protection circuit includes first control circuit and first switch, and the first switch is connected to the output voltage
Between the output and ground for controlling circuit；
The first control circuit receives the short-circuit indication signal, during the short-circuit indication signal is disarmed state, control
Make the first switch to turn off always, during the short-circuit indication signal is effective status, control the first switch the
Turned off in one period, turned in second time period, the error signal is reduced to zero, so that the adjustment pipe batch (-type)
Shut-off.
2. linear voltage regulator according to claim 1, it is characterised in that also including output voltage feedback circuit, for giving birth to
Into the feedback voltage of the current output voltage.
3. linear voltage regulator according to claim 2, it is characterised in that the short-circuit decision circuitry compares including first
Device,
The first input end of the first comparator receives the feedback voltage, and the second input, which is received, characterizes the short-circuit threshold value
Second reference voltage signal of voltage, output end exports the short-circuit indication signal.
4. linear voltage regulator according to claim 2, it is characterised in that also including buffering drive circuit, the buffering is driven
It is dynamic to be electrically connected between the control end of the output end of the output voltage controlling circuit and the adjustment pipe.
5. linear voltage regulator according to claim 2, it is characterised in that the output voltage controlling circuit, which includes first, to be missed
Poor amplifier；
The first input end of first error amplifier receives first reference voltage for characterizing the desired output voltage, the
Two inputs receive the feedback voltage, and output end exports the error signal.
6. linear voltage regulator according to claim 1, it is characterised in that
Two alternately occurred during the effective status of the first time period and second time period for the short-circuit indication signal
Period.
7. linear voltage regulator according to claim 6, it is characterised in that the first control circuit is produced including the first pulse
Raw circuit, the second pulse-generating circuit, the 3rd pulse-generating circuit, the first timer, the second timer, the first OR gate, first
With door and rest-set flip-flop；
The input of first pulse-generating circuit receives the short-circuit indication signal, and output end is connected to first OR gate
First input end, the second input, the reset terminal of the rest-set flip-flop and second timer of first OR gate
Output end of the reset terminal with the 3rd pulse-generating circuit be connected；
Described first receives the output signal of the short-circuit indication signal and first OR gate with two inputs of door respectively,
Output end is connected to the input end of first timer；
The output end of first timer is connected with the set end of the rest-set flip-flop, the output end output of the rest-set flip-flop
Control signal for controlling the first switch turn-on and turn-off；
The input of second pulse-generating circuit receives the control signal, output end respectively with first timer
Reset terminal, the input end of second timer are connected, the output end of second timer and the 3rd pulses generation electricity
The input on road is connected.
8. according to any one described linear voltage regulator in claim 1-7, it is characterised in that also including current-limiting circuit,
When the short-circuit indication signal is disarmed state, current-limiting circuit control flow through the adjustment pipe electric current be less than or
Equal to the first limitation electric current,
When the short-circuit indication signal is effective status, current-limiting circuit control flow through the adjustment pipe electric current be less than or
Equal to the second limitation electric current,
The second limitation electric current is less than the described first limitation electric current.
9. linear voltage regulator according to claim 8, it is characterised in that the current-limiting circuit include current sampling circuit,
Current limliting benchmark generative circuit, the second error amplifier and diode；
The current sampling circuit is used to obtain the sampled voltage for characterizing and flowing through the adjustment tube current；
The current limliting benchmark generative circuit is when the short-circuit indication signal is disarmed state, and output characterizes the first limitation electricity
3rd reference voltage of stream, when the short-circuit indication signal is effective status, output table characterizes the 4th of the second limitation electric current
Reference voltage, the 4th reference voltage is less than the 3rd reference voltage；
The first input end of second error amplifier is connected with the output end of the current sampling circuit, the second input with
The current limliting benchmark generative circuit is connected, and output end is connected with the negative electrode of the diode；
The anode of the diode is connected with the output end of the output voltage controlling circuit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410706834.4A CN104466912B (en) | 2014-11-27 | 2014-11-27 | A kind of linear voltage regulator with short-circuit protection |
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| CN201410706834.4A CN104466912B (en) | 2014-11-27 | 2014-11-27 | A kind of linear voltage regulator with short-circuit protection |
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| CN104466912B true CN104466912B (en) | 2017-08-25 |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106505540A (en) * | 2016-12-20 | 2017-03-15 | 奉化市慧光太阳能科技有限公司 | Battery lamp load short-circuit protection circuit |
| TWI619322B (en) * | 2016-12-30 | 2018-03-21 | 新唐科技股份有限公司 | Power switching device |
| TWI674722B (en) * | 2018-07-02 | 2019-10-11 | 茂達電子股份有限公司 | Detection circuit and switch module using the same |
| CN114793060A (en) * | 2021-01-25 | 2022-07-26 | 圣邦微电子（北京）股份有限公司 | Linear voltage regulator and power management chip |
| CN112994430B (en) * | 2021-02-26 | 2022-03-22 | 西安微电子技术研究所 | Multi-mode combined short-circuit protection circuit and working method and application thereof |
| CN113258917B (en) * | 2021-07-13 | 2021-09-24 | 广州市保伦电子有限公司 | Control device for monitoring and protecting electric equipment |
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Address after: 310051 No. 6 Lianhui Street, Xixing Street, Binjiang District, Hangzhou City, Zhejiang Province Patentee after: Silergy Semiconductor Technology (Hangzhou ) Co., Ltd. Address before: 310012 Xihu District, Hangzhou, Wensanlu Road, No. 90, East Software Park, science and technology building, A1501 Patentee before: Silergy Semiconductor Technology (Hangzhou ) Co., Ltd. |