CN103516190A - Switch power supply over current/over power protection method, protection circuit and switch power supply - Google Patents
Switch power supply over current/over power protection method, protection circuit and switch power supply Download PDFInfo
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- CN103516190A CN103516190A CN201310479854.8A CN201310479854A CN103516190A CN 103516190 A CN103516190 A CN 103516190A CN 201310479854 A CN201310479854 A CN 201310479854A CN 103516190 A CN103516190 A CN 103516190A
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Abstract
The invention provides an over current/over power protection circuit of a switch power supply. The protection circuit comprises a line voltage compensation circuit and an over current/over power protection module. The line voltage compensation circuit is used for receiving a first signal which is matched with a PWM signal in duty cycle, and generates at least two ratio signals proportional to the first signal. A ratio signal, which conforms to a predefined rule, in the ratio signals is selected as a compensation signal output by the line voltage compensation circuit. The over current/over power protection module is used for receiving the line voltage compensation signal and a target signal, and determines whether the target signal meets an over current/over power condition according to the line voltage compensation signal. The line voltage compensation circuit is arranged into the relationship between multi segment type compensation current Icomp and aliasing wave voltage Vsaw, so that the switch power supply can be compensated under the condition of low line voltage. Constant over current protection or constant over power protection is realized in a full line voltage range.
Description
Technical field
The present invention relates to field of switch power, in particular, relate to a kind of overcurrent/overpower protection method, protective circuit and Switching Power Supply of Switching Power Supply.
Background technology
Along with the develop rapidly of electronics and information industry, Switching Power Supply is widely used in fields such as computer, power equipment, instrument and meter, LED illumination, medicine equipment, military industry equipments.Conventionally, Switching Power Supply is to convert external AC (as civil power 220V, 380V etc.) to a galvanic current with supply load.
Switching Power Supply has a lot of defencive functions, as over-and under-voltage protection, overheat protector, overcurrent protection, overpower protection etc.These defencive functions have been avoided the damage of the integrated IC of power and whole Switching Power Supply.
Conventionally, overcurrent protection and overpower protection, within the scope of full line voltage, do not possess constant protection value, therefore need to carry out line voltage compensation to it.And inventor finds, compensating circuit of the prior art is when low line voltage, and overcurrent protection or overpowering protection value are very low, can not realize permanent power protection.
Summary of the invention
In view of this; the invention provides a kind of overcurrent/overpower protection method, protective circuit and Switching Power Supply of Switching Power Supply; to overcome in prior art Switching Power Supply when the low line voltage, overcurrent protection value is lower, can not realize the problem of full line voltage firm power protection.
For achieving the above object, the invention provides following technical scheme:
Overcurrent/overpower protection circuit, comprising:
Line voltage compensation circuit, for receive one with the suitable first signal of the duty ratio of pwm signal, and produce at least two with the proportional scaling signal of described first signal, select to meet in described scaling signal the compensating signal that the scaling signal of preset rules is exported as described line voltage compensation circuit;
Overcurrent/overpower protection module, receives described line voltage compensation signal and echo signal, and judges according to described line voltage compensation signal whether described echo signal meets overcurrent/over-power condition.
Preferably, described first signal is the sawtooth pattern voltage signal that the oscillator in described switching power source control circuit produces.
Preferably; when the output signal of described line voltage compensation circuit is applied to the first input end of the comparator in described overcurrent/overpower protection module; during the second input termination first threshold voltage of described comparator, the scaling signal that meets preset rules in the described scaling signal of described selection as the compensating signal of described line voltage compensation circuit output is:
Be chosen in the compensating signal that the minimum scaling signal in the corresponding described scaling signal of same first signal is exported as described line voltage compensation circuit.
Preferably; when the output signal of described line voltage compensation circuit is applied to the first input end of the comparator in described overcurrent/overpower protection module; when the second input of described comparator and the Cs of Switching Power Supply end is connected, in the described scaling signal of described selection, meets the compensating signal that the scaling signal of preset rules exports as described line voltage compensation circuit and be:
Be chosen in the compensating signal that the maximum scaling signal in the corresponding described scaling signal of same first signal is exported as described line voltage compensation circuit.
Preferably, described line voltage compensation circuit comprises: voltage-current converter and current-voltage converter;
Described voltage-current converter is converted to the first current ratio signal and the second current ratio signal by described first signal and predeterminated voltage signal respectively; and will in described the first current ratio signal and described the second current ratio signal, compared with small-signal, be delivered to described current-voltage converter, form voltage compensation signal to described overcurrent/overpower protection module.
Preferably, described voltage-current converter comprises: the first voltage-current converter, second voltage-current converter, the first current mirror, the second current mirror and the first current comparator;
Described the first voltage-current converter gathers described first signal, and the output of described the first voltage-current converter is connected with the input of described the first current mirror; Described second voltage-current converter receives described predeterminated voltage signal, and the output of described second voltage-current converter is connected with the input of described the second current mirror;
The first output of described the first current mirror is connected with the first output of described the second current mirror, and public connecting end is connected with the first input end of described the first current comparator;
The second output of described the first current mirror is connected with the second output of described the second current mirror, and public connecting end is connected with the second input of described the first current comparator; The output of described the first current comparator, as the output of described voltage-current converter, is connected with described compensating resistance.
Preferably, described current-voltage converter is compensating resistance.
Overcurrent/overpower protection method, be applied to Switching Power Supply, described Switching Power Supply comprises: for the control circuit of the conducting of power ratio control pipe and cut-off, described control circuit comprises overcurrent/overpower protection module, comprising:
The suitable first signal of duty ratio of collection one and pwm signal; and produce at least two to the proportional scaling signal of described first signal; select to meet in described scaling signal the scaling signal of preset rules as the compensating signal of output, and described compensating signal is loaded on to described overcurrent/overpower protection module.
Preferably, described first signal is the sawtooth pattern voltage signal that the oscillator in described switching power source control circuit produces.
, it is characterized in that, comprise the overcurrent/overpower protection circuit described in above-mentioned any one.
Known via above-mentioned technical scheme; compared with prior art; the invention provides a kind of overcurrent/overpower protection circuit of Switching Power Supply; comprise: line voltage compensation circuit and overcurrent/overpower protection module; wherein; line voltage compensation circuit for receive one with the suitable first signal of the duty ratio of pwm signal; and produce at least two scaling signals proportional to first signal, in selection percentage signal, meet the scaling signal of preset rules as the compensating signal of line voltage compensation circuit output.Overcurrent/overpower protection module is used for receiving line voltage compensation signal and echo signal, and judges according to line voltage compensation signal whether echo signal meets overcurrent/over-power condition.Visible; by line voltage compensation circuit being arranged to the relation of offset current Icomp and the sawtooth voltage Vsaw of multisection type; make Switching Power Supply in the situation that of low line pressure, also can compensate Switching Power Supply, reached constant overcurrent protection or constant overpower protection within the scope of full line voltage.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only embodiments of the invention, for those of ordinary skills, do not paying under the prerequisite of creative work, other accompanying drawing can also be provided according to the accompanying drawing providing.
Fig. 1 is the circuit diagram of the switch power supply current protective circuit of available technology adopting;
Fig. 2 is the circuit diagram of another kind of Switching Power Supply current foldback circuit in prior art;
Fig. 3 is the compensated curve figure of Switching Power Supply overcurrent protection in prior art;
The circuit diagram of a kind of Switching Power Supply current foldback circuit that Fig. 4 provides for the embodiment of the present invention;
The compensated curve figure that Fig. 5 is the current foldback circuit that adopts the present embodiment and provide;
The specific implementation circuit diagram of the voltage-current converter that Fig. 6 provides for the embodiment of the present invention;
Fig. 7 is the schematic diagram of a kind of Output rusults of current comparator in Fig. 6;
The circuit diagram of the another kind of Switching Power Supply current foldback circuit that Fig. 8 provides for the embodiment of the present invention;
The circuit diagram of voltage-electric pressure converter that Fig. 9 provides for the embodiment of the present invention;
Figure 10 is the schematic diagram of a kind of Output rusults of current comparator in Fig. 9.
Embodiment
For quote and know for the purpose of, the explanation of the technical term hereinafter using, write a Chinese character in simplified form or abridge and be summarized as follows:
The abbreviation of OSC:oscillator, means oscillator.
OCP:Over current protection, overcurrent protection.
OPP:Over power protection, overpower protection.
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 clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, rather than whole embodiment.Embodiment based in the present invention, those of ordinary skills, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.
Refer to Fig. 1; for the circuit diagram of realizing of switch power supply current protection conventional in prior art, the current foldback circuit of this Switching Power Supply (OCP) 200 comprises: diode rectifier bridge 100, filter capacitor C101; transformer primary side inductance L p1; oscillator 110(OSC), logic control circuit 120, drive circuit 125; voltage-current converter 140; compensating resistance R115, power tube M102, current comparator 126 and sampling resistor R103.
Concrete, diode rectifier bridge 100 is converted into direct voltage by alternating voltage Vac, its output plus terminal is connected with the first end of filter capacitor C101 and the different name end of transformer primary side inductance L p1 respectively, and the second end of filter capacitor C101 is connected and ground connection with the output negative terminal of diode rectifier bridge 100.The Same Name of Ends of transformer primary side inductance L p1 with by power tube M102, be connected with the first end of sampling resistor R103, the second end ground connection of sampling resistor R103.
The first end of the clock signal terminal andlogic control circuit 120 of oscillator 110 is connected, and the second end of this logic control circuit 120 is connected with the control end of power tube M102 by drive circuit 125, for unlatching and the shutoff of power ratio control pipe M102.
The sawtooth signal end of oscillator 110 is connected with the input of voltage-current converter 140, the output of voltage-current converter 140 is connected with the first end of compensating resistance R115 and the first input end of current comparator 126 respectively, the second end of compensating resistance R115 is connected with the first end of sampling resistor R103, the second input termination predeterminated voltage Vref of this current comparator 126, its 3rd end that compares output andlogic control circuit 120 are connected, for line voltage compensation amount being superimposed upon to the current sample pin CS of the integrated IC of Switching Power Supply.
In conjunction with above-mentioned annexation and Fig. 1; the operation principle of this current foldback circuit is: the electric current of Dang Yuan limit inductance L p1 is greater than after certain threshold value; current comparator 126 control logic control circuits 120; and then switch-off power pipe M102; thereby limited the size of primary current, reached the object of the power converter of protection switch power supply.
Refer to Fig. 2; for another kind of conventional Switching Power Supply circuit overcurrent protection in prior art; this circuit comprises: diode rectifier bridge 301, filter capacitor C306, transformer primary side inductance L p2; oscillator 310; logic control circuit 320, voltage-electric pressure converter 340, power tube M302; current comparator 328, sampling resistor R303.
The operation principle of this current foldback circuit and the operation principle of the current protecting circuit in Fig. 1 are similar, are not described in detail in this.Different, this circuit is line voltage compensation amount to be superimposed upon to one end of current comparator, directly the threshold voltage of control switch power supply CS end.
In conjunction with Fig. 1 and Fig. 2, to be not difficult to find, the two is all to utilize the rising edge voltage Vsaw of the sawtooth waveforms of oscillator (OSC) to compensate the line voltage of current comparator (OCP).Although two kinds of modes are that the form of expression is different; but control principle is identical; be specially: when overcurrent protection (OCP) or overpower protection (OPP), the duty ratio Duty of the corresponding PWM of low line voltage is larger, and the duty ratio Duty of the PWM that contrary high line voltage is corresponding is less.For this reason by the rising edge voltage Vsaw of the sawtooth waveforms of the oscillator OSC that samples by duty ratio Duty, and through suitable conversion, can reach the desired value of line voltage compensation.Finally, the former limit of the inductance of chip controls peak current Ipeak is rendered as and increases progressively trend with PWM duty ratio Duty, reaches the object of line voltage compensation.
Be the lowest high-current value that above-mentioned current foldback circuit has limited the former limit inductance of Switching Power Supply, thereby restriction Liao Yuan limit is transferred to the maximum power of secondary, has protected the cause thermal damage of Switching Power Supply and output loading element.
But, the compensating circuit of available technology adopting, its compensation rate Vcomp or Icomp are that sawtooth waveforms (Vsaw) signal in oscillator OSC circuit generates, and compensation rate Vcomp or Icomp are the once linear functions of voltage Vsaw.As shown in Figure 3, conventional compensating circuit is when low line voltage, and overcurrent protection or overpowering protection value are very low, can not realize permanent power protection, is difficult to meet the strict clients' of ask for something needs.
In order to solve in prior art Switching Power Supply when the low line voltage, overcurrent protection value is lower, can not realize the problem of full line voltage firm power protection, the invention provides a kind of Switching Power Supply current foldback circuit and Switching Power Supply.
Refer to accompanying drawing 4; for a kind of Switching Power Supply overcurrent/overpower protection circuit 400 provided by the invention; be applied to Switching Power Supply; comprise: line voltage compensation circuit and overcurrent/overpower protection module, wherein, overcurrent/overpower protection module 410 comprises: logic controller 420; voltage-current converter 500; compensating resistance R415, drive circuit 425, overcurrent comparator 426.
In conjunction with Fig. 4, the annexation of foregoing circuit element is described:
The first end of the clock signal terminal andlogic control device 420 of oscillator 410 is connected, and the second end of this logic controller 420 is connected with the control end of power tube M402 by drive circuit 425, for unlatching and the shutoff of power ratio control pipe M402.
The sawtooth signal end of oscillator 410 is connected with the input of voltage-current converter 500, the output of voltage-current converter 500 is connected with the first end of compensating resistance R415 and the first input end of current comparator 426 respectively, the second end of compensating resistance R415 is connected with the second end of sampling resistor R403, the second input termination predeterminated voltage Vref of this current comparator 426, its 3rd end that compares output andlogic control device 420 are connected, for line voltage compensation amount being superimposed upon to the current sample pin CS of the integrated IC of Switching Power Supply.
Wherein, line voltage compensation circuit, for receive one with the suitable first signal of the duty ratio of pwm signal, and produce at least two with the proportional scaling signal of above-mentioned first signal, select to meet in aforementioned proportion signal the compensating signal that the scaling signal of preset rules is exported as above-mentioned line voltage compensation circuit;
Overcurrent/overpower protection module is used for receiving above-mentioned line voltage compensation signal and echo signal, and judges according to above-mentioned line voltage compensation signal whether above-mentioned echo signal meets overcurrent/over-power condition.
It should be noted that, in the line voltage compensation circuit that the present embodiment provides and prior art, the first protective circuit of switch power source is more known, and unlike the prior art, other components and parts are all similar for the voltage-current converter in the present embodiment.Consider the problems such as circuit hardware consumption, the voltage-current converter 500 that the present embodiment provides adopts the offset current Icomp of two-part and the relation of sawtooth voltage Vsaw, and each segmentation, the relation of offset current Icomp and voltage Vsaw is still linear functional relation, but the linear gradient between segmentation is different.And when same voltage Vsaw, choose the value of less compensating circuit Icomp, as shown in Figure 7.Like this, the compensating circuit after improvement (the present embodiment), the overcurrent protection of switch power supply system and the curve of overpower protection are transformed into Line2 from Line1, have reached constant OCP or constant OPP protection within the scope of full line voltage, as shown in Figure 5.
It should be noted that, in voltage-current converter provided by the invention, the relation of offset current Icomp and sawtooth voltage Vsaw can be two ends formula piecewise function, also can be multisection type function, or be that MathCAD model calculates the curve that demonstration compensated curve is a curvature variation, do not limit herein.
Preferably, the present embodiment provides a kind of specific implementation circuit of voltage-current converter, as shown in Figure 6, this voltage-current converter 500 comprises: the first voltage-current converter 560, second voltage-current converter 550, the first current mirror 520, the second current mirror 540 and the first current comparator 530.
Wherein, the first voltage-current converter 560 gathers the sawtooth voltage Vsaw of oscillator, and its output is connected with the input of the first current mirror 520.Second voltage-current converter 550 receives predeterminated voltage Vref, and its output is connected with the input of the second current mirror 540.The first output of above-mentioned the first current mirror is connected with the first output of the second current mirror, and public connecting end is connected with the first input end of the first current comparator 530.The second output of the first current mirror is connected with the second output of the second current mirror, and public connecting end is connected with the second input of the first current comparator 530.The output of the first current comparator 530 is as the output of this voltage-current converter, and R415 is connected with compensating resistance.
The operation principle of the voltage-current converter 500 that the present embodiment provides is:
The sawtooth voltage Vsaw with wired information of voltage that the first voltage-current converter 560 reception oscillators produce, and voltage Vsaw is changed into electric current I saw.Concrete, Isaw=Vsaw/R1.Wherein resistance R 1 is the resistance in the first voltage-current converter 560, in figure, does not draw.Afterwards, the electric current I saw of generation processes through the first current mirror 520, produces image current or is multiplied by the electric current of suitable coefficient, and wherein, coefficient can be n1 and n2.
Equally, Reference voltage Vref converts electric current I ref to through second voltage-current converter.Afterwards, the electric current I ref of generation processes through the second current mirror 540, produces image current or is multiplied by the electric current of suitable coefficient, and wherein, coefficient can be n3 and n4.
In conjunction with the annexation of Fig. 6, can obtain:
Ia=n1·(Vsaw/R1)–n3·(Vref/R2)
Ib=n2·(Vsaw/R1)–n4·(Vref/R2)
The compensation rate that switch power supply system needs: Icomp=kChoose (Ia, Ib), in the present embodiment, this current comparator 530 is chosen the smaller value in Ia and Ib.Be the graph of a relation of its Icomp and Vsaw as shown in Figure 7, when a certain voltage Vsaw, choose the smaller value of electric current I comp, or when a certain electric current I comp, choose less voltage Vsaw, as the solid line part in Fig. 7.It should be noted that, in Fig. 7, determining of the intersection point of two straight lines can be the modeling acquisition by repeatedly, and in a certain Switching Power Supply, once set the value of this intersection point,, after Switching Power Supply is dispatched from the factory, the value of this intersection point no longer changes.
Visible; the voltage-current converter that the present embodiment provides adopts the offset current Icomp of two-part and the relation of sawtooth voltage Vsaw; make the overcurrent protection of switch power supply system and the Line1 of the curve of overpower protection from Fig. 5 be transformed into Line2;; the in the situation that of low line pressure; also can compensate Switching Power Supply, reach constant overcurrent protection or constant overpower protection within the scope of full line voltage.
Embodiment bis-
Refer to accompanying drawing 8; for another kind of Switching Power Supply overcurrent/overpower protection circuit 600 provided by the invention, be applied to Switching Power Supply, comprising: diode rectifier bridge 601; filter capacitor C611; transformer primary side inductance L p6, oscillator 610, logic control circuit 620; drive circuit 625; voltage-electric pressure converter 800, power tube M602, current comparator and sampling resistor R603.
Wherein, diode rectifier bridge 601 is converted into direct voltage by alternating voltage Vac, its output plus terminal is connected with the first end of filter capacitor C611 and the different name end of transformer primary side inductance L p6 respectively, and the second end of filter capacitor C611 is connected and ground connection with the output negative terminal of diode rectifier bridge 601.The Same Name of Ends of transformer primary side inductance L p6 with by power tube M602, be connected with the first end of sampling resistor R603, the second end ground connection of sampling resistor R603.
The first end of the clock signal terminal andlogic control device 620 of oscillator 610 is connected, and the second end of this logic controller 620 is connected with the control end of power tube M602 by drive circuit 625, for unlatching and the shutoff of power ratio control pipe M802.
The sawtooth signal end of oscillator 610 is connected with the input of voltage-electric pressure converter 800, the output direct effect of voltage-electric pressure converter 800 is to an input of current comparator, and the first end of another input termination sampling resistor R603 of current comparator, the 3rd end of the output andlogic control circuit 620 of current comparator is connected, for line voltage compensation amount being superimposed upon to the current sample pin CS of the integrated IC of Switching Power Supply.
Embodiment mono-is superimposed upon CS leads ends by compensation rate, and the present embodiment is compensation rate to be superimposed upon to an input of OCP comparator, and its operation principle and embodiment mono-are similar.Voltage-electric pressure converter in the present embodiment also adopts the relation of Vcomp and the Vsaw of multisection type, and its operation principle and embodiment mono-are similar.
Preferably, the present embodiment also provides a kind of specific implementation circuit of voltage-electric pressure converter, as shown in Figure 9, comprising: tertiary voltage-current converter 830, the 4th voltage-current converter 840, the 3rd current mirror 820, the 4th current mirror 840, the second current comparator 850 and current-voltage converter 860.
Wherein the annexation of each former device is:
Tertiary voltage-current converter gathers the sawtooth voltage Vsaw of oscillator, and its output is connected with the input of the 3rd current mirror.The 4th voltage-current converter receives predeterminated voltage Vref, and its output is connected with the input of the 4th current mirror.The first output of the 3rd current mirror is connected with the first output of the 4th current mirror, and public connecting end is connected with the first input end of the second current comparator.The second output of the 3rd current mirror is connected with the second output of the 4th current mirror, and public connecting end is connected with the second input of the second current comparator.The output of the second current comparator is connected with the input of current-voltage converter, and the output of above-mentioned current-voltage converter is as the output of this voltage-current converter.
In the present embodiment, switch power supply system need to be realized the voltage compensation curve shown in Figure 10, and for this reason, the second current comparator 850 in Fig. 9 need to be selected the higher value in Ia and Ib and be multiplied by coefficient k.And be compensated voltage Vcomp=Vref+IcompR8 by current-voltage converter 860, wherein, Vref and R8 are some parameters in current-voltage converter 860.
The voltage that the present embodiment provides-electric pressure converter adopts the bucking voltage Vcomp of two-part and the relation of sawtooth voltage Vsaw; make Switching Power Supply in the situation that of low line pressure; also can compensate Switching Power Supply, reach constant overcurrent protection or constant overpower protection within the scope of full line voltage.
From embodiment mono-and embodiment bis-, be not difficult to draw, above-mentioned first signal is the sawtooth pattern voltage signal that the oscillator in above-mentioned switching power source control circuit produces.And the output signal of working as above-mentioned line voltage compensation circuit is applied to the first input end of the comparator in above-mentioned overcurrent/overpower protection module; when second of above-mentioned comparator is inputted termination first threshold voltage, be chosen in the compensating signal that the minimum scaling signal in the corresponding aforementioned proportion signal of same first signal is exported as above-mentioned line voltage compensation circuit.When the output signal of above-mentioned line voltage compensation circuit is applied to the first input end of the comparator in above-mentioned overcurrent/overpower protection module; when the second input of above-mentioned comparator is connected with the Cs of Switching Power Supply end, be chosen in the compensating signal that the maximum scaling signal in the corresponding aforementioned proportion signal of same first signal is exported as above-mentioned line voltage compensation circuit.
On the basis of above-described embodiment; the present invention also provides a kind of overcurrent/overpower protection method of Switching Power Supply; be applied to above-mentioned Switching Power Supply; above-mentioned Switching Power Supply comprises: for the control circuit of the conducting of power ratio control pipe and cut-off; above-mentioned control circuit comprises overcurrent/overpower protection module, and the method comprises:
The suitable first signal of duty ratio of collection one and pwm signal; and produce at least two to the proportional scaling signal of above-mentioned first signal; select to meet in aforementioned proportion signal the scaling signal of preset rules as the compensating signal of output, and above-mentioned compensating signal is loaded on to above-mentioned overcurrent/overpower protection module.
Preferably, above-mentioned first signal is the sawtooth pattern voltage signal that the oscillator in above-mentioned switching power source control circuit produces.The operation principle of this guard method, referring to above-described embodiment, no longer repeats to discuss at this.Except this, the present embodiment also provides a kind of Switching Power Supply, comprises any one line voltage compensation circuit in above-described embodiment.
To sum up above-mentioned: the overcurrent/overpower protection circuit that the invention provides a kind of Switching Power Supply; comprise: line voltage compensation circuit and overcurrent/overpower protection module; wherein; line voltage compensation circuit for receive one with the suitable first signal of the duty ratio of pwm signal; and produce at least two scaling signals proportional to first signal, in selection percentage signal, meet the scaling signal of preset rules as the compensating signal of line voltage compensation circuit output.Overcurrent/overpower protection module is used for receiving line voltage compensation signal and echo signal, and judges according to line voltage compensation signal whether echo signal meets overcurrent/over-power condition.Visible; by line voltage compensation circuit being arranged to the relation of offset current Icomp and the sawtooth voltage Vsaw of multisection type; make Switching Power Supply in the situation that of low line pressure, also can compensate Switching Power Supply, reached constant overcurrent protection or constant overpower protection within the scope of full line voltage.
In this specification, each embodiment adopts the mode of going forward one by one to describe, and each embodiment stresses is the difference with other embodiment, between each embodiment identical similar part mutually referring to.For the device providing for embodiment, because its method providing with embodiment is corresponding, so description is fairly simple, relevant part partly illustrates referring to method.
Above-mentioned explanation to provided embodiment, makes professional and technical personnel in the field can realize or use the present invention.To the multiple modification of these embodiment, will be apparent for those skilled in the art, General Principle as defined herein can, in the situation that not departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention will can not be restricted to these embodiment shown in this article, but will meet the widest scope consistent with principle provided in this article and features of novelty.
Claims (10)
1. overcurrent/overpower protection circuit of Switching Power Supply, is characterized in that, comprising:
Line voltage compensation circuit, for receive one with the suitable first signal of the duty ratio of pwm signal, and produce at least two with the proportional scaling signal of described first signal, select to meet in described scaling signal the compensating signal that the scaling signal of preset rules is exported as described line voltage compensation circuit;
Overcurrent/overpower protection module, receives described line voltage compensation signal and echo signal, and judges according to described line voltage compensation signal whether described echo signal meets overcurrent/over-power condition.
2. overcurrent/overpower protection circuit according to claim 1, is characterized in that, described first signal is the sawtooth pattern voltage signal that the oscillator in described switching power source control circuit produces.
3. overcurrent/overpower protection circuit according to claim 1; it is characterized in that; when the output signal of described line voltage compensation circuit is applied to the first input end of the comparator in described overcurrent/overpower protection module; during the second input termination first threshold voltage of described comparator, the scaling signal that meets preset rules in the described scaling signal of described selection as the compensating signal of described line voltage compensation circuit output is:
Be chosen in the compensating signal that the minimum scaling signal in the corresponding described scaling signal of same first signal is exported as described line voltage compensation circuit.
4. overcurrent/overpower protection circuit according to claim 1; it is characterized in that; when the output signal of described line voltage compensation circuit is applied to the first input end of the comparator in described overcurrent/overpower protection module; when the second input of described comparator and the Cs of Switching Power Supply end is connected, in the described scaling signal of described selection, meets the compensating signal that the scaling signal of preset rules exports as described line voltage compensation circuit and be:
Be chosen in the compensating signal that the maximum scaling signal in the corresponding described scaling signal of same first signal is exported as described line voltage compensation circuit.
5. overcurrent/overpower protection circuit according to claim 1, is characterized in that, described line voltage compensation circuit comprises: voltage-current converter and current-voltage converter;
Described voltage-current converter is converted to the first current ratio signal and the second current ratio signal by described first signal and predeterminated voltage signal respectively; and will in described the first current ratio signal and described the second current ratio signal, compared with small-signal, be delivered to described current-voltage converter, form voltage compensation signal to described overcurrent/overpower protection module.
6. overcurrent/overpower protection circuit according to claim 5, it is characterized in that, described voltage-current converter comprises: the first voltage-current converter, second voltage-current converter, the first current mirror, the second current mirror and the first current comparator;
Described the first voltage-current converter gathers described first signal, and the output of described the first voltage-current converter is connected with the input of described the first current mirror; Described second voltage-current converter receives described predeterminated voltage signal, and the output of described second voltage-current converter is connected with the input of described the second current mirror;
The first output of described the first current mirror is connected with the first output of described the second current mirror, and public connecting end is connected with the first input end of described the first current comparator;
The second output of described the first current mirror is connected with the second output of described the second current mirror, and public connecting end is connected with the second input of described the first current comparator; The output of described the first current comparator, as the output of described voltage-current converter, is connected with described compensating resistance.
7. overcurrent/overpower protection circuit according to claim 5, is characterized in that, described current-voltage converter is compensating resistance.
8. overcurrent/overpower protection method of Switching Power Supply, is applied to Switching Power Supply, and described Switching Power Supply comprises: for the control circuit of the conducting of power ratio control pipe and cut-off, described control circuit comprises overcurrent/overpower protection module, it is characterized in that, comprising:
The suitable first signal of duty ratio of collection one and pwm signal; and produce at least two to the proportional scaling signal of described first signal; select to meet in described scaling signal the scaling signal of preset rules as the compensating signal of output, and described compensating signal is loaded on to described overcurrent/overpower protection module.
9. overcurrent/overpower protection method according to claim 8, is characterized in that, described first signal is the sawtooth pattern voltage signal that the oscillator in described switching power source control circuit produces.
10. a Switching Power Supply, is characterized in that, comprises the overcurrent/overpower protection circuit as described in any one in claim 1-7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310479854.8A CN103516190B (en) | 2013-10-14 | 2013-10-14 | Stream/overpower protection method, protection circuit and the Switching Power Supply excessively of a kind of Switching Power Supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310479854.8A CN103516190B (en) | 2013-10-14 | 2013-10-14 | Stream/overpower protection method, protection circuit and the Switching Power Supply excessively of a kind of Switching Power Supply |
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| Publication Number | Publication Date |
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| CN103516190A true CN103516190A (en) | 2014-01-15 |
| CN103516190B CN103516190B (en) | 2016-08-10 |
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| CN201310479854.8A Active CN103516190B (en) | 2013-10-14 | 2013-10-14 | Stream/overpower protection method, protection circuit and the Switching Power Supply excessively of a kind of Switching Power Supply |
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| CN (1) | CN103516190B (en) |
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| CN106208647A (en) * | 2015-05-04 | 2016-12-07 | 中兴通讯股份有限公司 | Over-current protection method and device |
| TWI631799B (en) * | 2017-03-30 | 2018-08-01 | 昂寶電子（上海）有限公司 | System for providing input undervoltage and overvoltage protection for power converter |
| CN111211668A (en) * | 2020-01-13 | 2020-05-29 | 深圳市高斯宝电气技术有限公司 | Constant power regulation method for digital switching power supply output |
| CN111600470A (en) * | 2020-06-10 | 2020-08-28 | 杰华特微电子（杭州）有限公司 | Switching power supply control circuit and control method |
| CN116093893A (en) * | 2023-04-07 | 2023-05-09 | 深圳市联明电源有限公司 | Constant-current driving protection circuit, laser pumping system and constant-current driving protection method |
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| CN202009331U (en) * | 2011-05-05 | 2011-10-12 | 上海新进半导体制造有限公司 | Circuit for controlling constant current output in switch power source |
| CN102324843A (en) * | 2011-05-17 | 2012-01-18 | 浙江大学 | High-precision sectional type linear slope compensation circuit |
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| US20110019445A1 (en) * | 2009-07-22 | 2011-01-27 | Bcd Semiconductor Manufacturing Limited | Method and apparatus for controlling power converter output characteristics |
| CN202009331U (en) * | 2011-05-05 | 2011-10-12 | 上海新进半导体制造有限公司 | Circuit for controlling constant current output in switch power source |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106208647A (en) * | 2015-05-04 | 2016-12-07 | 中兴通讯股份有限公司 | Over-current protection method and device |
| CN106208647B (en) * | 2015-05-04 | 2020-05-05 | 中兴通讯股份有限公司 | Overcurrent protection method and device |
| TWI631799B (en) * | 2017-03-30 | 2018-08-01 | 昂寶電子（上海）有限公司 | System for providing input undervoltage and overvoltage protection for power converter |
| CN111211668A (en) * | 2020-01-13 | 2020-05-29 | 深圳市高斯宝电气技术有限公司 | Constant power regulation method for digital switching power supply output |
| CN111600470A (en) * | 2020-06-10 | 2020-08-28 | 杰华特微电子（杭州）有限公司 | Switching power supply control circuit and control method |
| CN111600470B (en) * | 2020-06-10 | 2023-08-29 | 杰华特微电子股份有限公司 | Switching power supply control circuit and control method |
| CN116093893A (en) * | 2023-04-07 | 2023-05-09 | 深圳市联明电源有限公司 | Constant-current driving protection circuit, laser pumping system and constant-current driving protection method |
| CN116093893B (en) * | 2023-04-07 | 2023-07-07 | 深圳市联明电源有限公司 | Constant-current driving protection circuit, laser pumping system and constant-current driving protection method |
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|---|---|
| CN103516190B (en) | 2016-08-10 |
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