CN203734296U - Power supply short circuit protection circuit - Google Patents
Power supply short circuit protection circuit Download PDFInfo
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- CN203734296U CN203734296U CN201320686546.8U CN201320686546U CN203734296U CN 203734296 U CN203734296 U CN 203734296U CN 201320686546 U CN201320686546 U CN 201320686546U CN 203734296 U CN203734296 U CN 203734296U
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Abstract
The utility model provides a power supply short circuit protection circuit. The protection circuit includes a voltage detection module, a switch control module, and a time-delay holding module. The voltage detection module is used for detecting a voltage related to a short circuit of an output terminal of a power supply. On the basis of the detected voltage, it is determined if there is a short circuit at the output terminal of the power supply. When it is determined that a short circuit happens to the output terminal of the power supply, a control signal is output to a terminal which controls a control IC to output or stop outputting a PWM signal. According to the technical scheme, no matter if the control IC of a power circuit is capable of short circuit protection, the protection circuit can reliably make the control IC stop outputting the PWM signal to achieve the purpose of short circuit protection, and can reduce the valid value of an output current when a short circuit happens to the output terminal of the power supply.
Description
Technical field
The utility model relates to a kind of output short circuit protection circuit of power supply.
Background technology
Power supply, as the requisite part of electrical equipment, is one of important guarantee of electrical equipment normal operation always.Particularly, Switching Power Supply has that volume is little, lightweight, conversion efficiency high, is widely used in the various electronic equipments in the fields such as Industry Control, communication office, household consumption.Power supply is generally made up of elements such as switch element and transformer such as the control integration circuit for pulse width modulation (Pulse Width Modulation:PWM) (following, referred to as controlling IC), power field effect transistor or triodes.
According to the difference of electronic equipment, the power supply that this electronic equipment uses also adopts different technical specifications and index, especially technical specification and the index of overvoltage, the various defencive functions such as overheated.In the time that the load of power supply is broken down, output current tends to increase, and even can cause output to be short-circuited, and now, needs promptly power cutoff, prevents that excessive electric current from burning out other element or the circuit of equipment.Therefore, output short circuit protection function is as the very important function of power supply and receive much concern.
In order to reach short-circuit protection object, conventionally, control IC and can detect the signal relevant to output end voltage or electric current, and judge whether to occur short-circuit state, to stop output or output pwm signal.At present, much control IC self and just possess the overpowering short-circuit protection function of primary side.To detect the primary side control IC supply power voltage value that reflects output end voltage as example, as shown in Figure 1, there is short circuit at output, and when short circuit power output reaches the overpowering threshold value of primary side, the voltage for giving the primary coil T1 two ends of controlling IC power supply of transformer starts decline, thus, via resistance R 7, after rectifier diode D1 and level and smooth capacitor C 3, directly supply with the voltage drop of the power end VCC that controls IC, below power end VCC drops to the threshold value being specified by control IC time, control the short-circuit protection function work of IC inside, stop output pwm signal, power supply is not exported.Wherein, resistance R1, the R2 for two dividing potential drops of the left part in Fig. 1, in the time of power initiation, charge to capacitor C 3, starts so that control IC.
But, be output as low-voltage at power supply, in the situation of large electric current, for example, at output voltage below 5V, output current is in situation more than 10A, in the time there is short circuit in the output of power circuit, because the leakage inductance of transformer is large, or the reasons such as secondary short circuited output impedance is excessive, although the variation of power output has reached the overpowering threshold value of an elementary side when short circuit, but, the voltage at the primary coil T1 two ends of the transformer in Fig. 1 can not drop to be made to control below the threshold value of regulation that IC stops output pwm signal, can not realize short-circuit protection even possess the control IC of the overpowering short-circuit protection function of primary side.
For another example, in the time that power supply is multichannel output, there is short circuit in a road therein, in the situation of other road output no-load, although short circuit power output can make an elementary side of power supply reach overpowering threshold value, the voltage of the power end VCC of the control IC of primary side can not drop to be made to control below the threshold value of regulation that IC stops output pwm signal.Can not realize short-circuit protection even possess the control IC of the overpowering short-circuit protection function of primary side.
Utility model content
The utility model is to propose in view of the above problems, and the purpose of this utility model is, can make reliably to control IC and stop the power protecting circuit of output pulse width modulation signal while providing a kind of output at power supply to produce short circuit.
According to a technical scheme of the present utility model; the utility model provides a kind of power supply short-circuit protective circuit; it,, having while producing short circuit for the output of the power supply of the control IC of output pulse width modulation signal, makes described control IC stop output pulse width modulation signal.Described power supply short-circuit protective circuit comprises: voltage detection module, its first input end is connected with the terminal of the voltage of the short-circuit state of the output of detection reflection power supply, the second input is connected with the terminal that receives reference voltage, the result that the voltage that the short circuit of the output based on to described reflection power supply is conditions associated and described reference voltage compare, judges signal from output output detections; Time delay keeps module, and its input is connected with the output of described voltage detection module, judges signal based on described detection, from output output switching signal; Switch control module, its input keeps the output of module to be connected with described time delay, output is connected with the control terminal that the described control of control IC exported/stopped output pulse width modulation signal, according to the switching signal that keeps module from described time delay, export/stop the signal of output pulse width modulation signal from the described control of the output output control IC being connected with described control terminal.Described time delay keeps module to judge signal based on described detection, export described switching signal to described switch control module, described switch control module is according to described switching signal, within the delay time that is kept module to specify by described time delay, make described control IC stop output pulse width modulation signal, and, through after described delay time, make described control IC output pulse width modulation signal.
Preferably, described voltage detection module has: two divider resistances that are connected in series above, the first input end that the upstream extremity that is positioned at the divider resistance of upstream is described voltage detection module, is positioned at the downstream ground connection of the divider resistance in downstream.The comparing element that the voltage obtaining by described divider resistance dividing potential drop and described reference voltage are compared, first end is connected with the tie point of more than selecting tie point between described two divider resistances that are connected in series above, the second end is the second input of described voltage detection module, the output that the 3rd end is described voltage detection module.
Preferably, described voltage detection module also has shunt capacitance, and one end of this shunt capacitance is connected with a tie point of described selection, other end ground connection.
Preferably, described time delay keeps module to comprise the discharge resistance and the electric capacity that are connected in parallel, the first tie point of described discharge resistance and described electric capacity is the output that described time delay keeps module, the second tie point ground connection of described discharge resistance and described electric capacity, described time delay keeps the output of module to keep the input of module to be connected with described time delay.More preferably, replace described time delay and keep the output of module to keep the input of module to be connected with described time delay, can also keep being also connected with charging resistor between the input of module and the output of described time delay maintenance module in described time delay.
Preferably, described switch control module comprises a switch element, the input that the first end of described switch element is described switch control module, the output that the second end is described switch control module, the 3rd end ground connection.
Preferably, described voltage detection module comprises two first, second divider resistances that are connected in series and the triode for dividing potential drop, one end of described the first divider resistance is the first input end of described voltage detection module, the other end is connected with one end of described the second divider resistance and the base stage of described triode, the second input of the very described voltage detection module of the transmitting of described triode, the output of the very described voltage detection module of current collection, the other end ground connection of described the second divider resistance.Described time delay keeps module to comprise the discharge resistance and the electric capacity that are connected in parallel, the first tie point of described discharge resistance and described electric capacity is the output that described time delay keeps module, the second tie point ground connection of described discharge resistance and described electric capacity, described time delay keeps the output of module to keep the input of module to be connected with described time delay.Described switch control module comprises a power field effect transistor, and the input that the grid of described power field effect transistor is described switch control module drains as the output of described switch control module, source ground.More preferably, described voltage detection module also has a shunt capacitance, and one end of this shunt capacitance is connected with the base stage of described triode, other end ground connection.In addition, can also replace described time delay and keep the output of module to keep the input of module to be connected with described time delay, can also keep being also connected with charging resistor between the input of module and the output of described time delay maintenance module in described time delay.
According to power supply short-circuit protective circuit of the present utility model; in the time there is short circuit in the output of power circuit; no matter whether the control IC in power circuit possesses short-circuit protection function; can both stop reliably the output action of the control IC for carrying out pulse width modulation; significantly reduce the effective value of output current, realize the object of short-circuit protection.
Brief description of the drawings
Fig. 1 is the circuit diagram that is illustrated in control of the prior art IC self and can realizes short-circuit protection.
Fig. 2 is the schematic diagram that represents the module of power supply short-circuit protective circuit of the present utility model.
Fig. 3 is the circuit diagram that represents the concrete example of power supply short-circuit protective circuit of the present utility model.
Fig. 4 is the oscillogram that is illustrated in the voltage of power end and the output current of circuit of the control IC under the power supply short-circuit protective circuit work shown in Fig. 3.
Embodiment
With reference to accompanying drawing, the execution mode of power supply short-circuit protective circuit 1 of the present utility model is described in detail.Wherein, for convenience of explanation, identical element is marked to identical Reference numeral.
Fig. 2 is the schematic diagram that represents the module of power supply short-circuit protective circuit 1 of the present utility model.Power supply short-circuit protective circuit 1 comprises: voltage detection module 11, it has two inputs and an output, first input end is connected with the power end VCC that controls IC, detect thus the voltage of the power end VCC that controls IC, the voltage of the power end VCC of this control IC is the voltage of the short-circuit state of the output for reflecting power supply, the second input is connected with the reference voltage terminal REF that controls IC, the voltage of power end VCC and the voltage of reference voltage terminal REF by the control IC to detecting compare, the magnitude relationship of result judges signal from output output detections based on the comparison, time delay keeps module 12, and it has an input and an output, and input is connected with the output of voltage detection module 11, and time delay keeps module 12 based on judging signal from the detection of voltage detection module 11, from output output switching signal, switch control module 13, it has an input and an output, input keeps the output of module 12 to be connected with time delay, output is connected with the output control terminal CS of the output pwm signal of controlling IC, based on the switching signal that keeps module 12 from time delay, output control terminal CS to the output pwm signal of controlling IC exports control signal, output control terminal CS controls IC to export/stop the terminal that enables of output pwm signal, and time delay keeps module 12 to carry out regulation control IC and stop the time of output pwm signal via this switch control module 13.In addition, voltage detection module 11, time delay keep module 12 and switch control module 13 all to have earth terminal.
Wherein, keep module 12 output detections to judge that the mode of signal comprises the multiple modes that can transmit detection information such as output voltage to time delay, for example, comprise the mode of output forward voltage, not output voltage and output reverse voltage, also comprise the signal that represents detection information is compared with the threshold value specifying in advance, the mode of exporting according to the size of the signal of expression detection information.In addition, also comprise above-mentioned multiple mode to the mode of switch control module 13 output switching signals, switch as long as can realize the state to making to control IC output pwm signal and make to control the state that IC stops output pwm signal.In the present embodiment, output detections judges that the mode of signal and output switching signal all adopts the mode of the voltage of the high and low level of output.
Output at power supply does not produce short circuit, the voltage of power end VCC of controlling IC be normal operating voltage (for example, for 18.5V), now, the voltage of this power end VCC by the voltage after the dividing potential drop of voltage detection module 11 inside higher than reference voltage terminal REF(for example, for 5V) voltage, the detection of voltage detection module 11 output low levels judges signal, time delay keeps module 12 to judge signal based on this low level detection, the switching signal of output low level, thus, switch control module 13 is based on this switching signal, not to the output control terminal CS output control signal of controlling IC, guarantee to control IC output pwm signal.On the other hand, produce short circuit at the output of power supply, control the voltage drop of the power end VCC of IC, although the voltage of power end VCC does not drop to the shutoff threshold voltage of controlling IC self, for example, as long as but the voltage obtaining after the dividing potential drop of the voltage that makes power end VCC by voltage detection module 11 inside (, below 4.4V) than the voltage of reference voltage terminal REF (for example, for 5V) magnitude of voltage of low regulation is (for example, for 0.6V), so, the detection that voltage detection module 11 is exported high level judges signal, after this, time delay keeps module 12 to export the switching signal of high level, switch control module 13 is based on this high level switching signal, to the control signal of output control terminal CS output low level of controlling IC, control IC and stop output pwm signal.Therefore, can make output current drop to 0, realize the short-circuit protection of power output end.
After this, keep module 12 regulation control IC to stop the time of output pwm signal by time delay, realize after the above-mentioned time through being specified by time delay maintenance module 12, switch control module 13 stops to the control signal of the output control terminal CS output low level of control IC, thus, make to control IC output pwm signal again, output current rises again.At the output of power supply still in short-circuit condition, voltage detection module 11 detects the voltage drop of the power end VCC that controls IC again, control signal by from switch control module 13 to the output control terminal CS output low level of control IC, to stop controlling the output of IC, if the output of power supply is always in short-circuit condition, the output action of starting/closing control IC repeatedly, therefore, output batch (-type) electric current, to reduce the effective value of output current.Recovering at the output of power supply is normally that in the settled situation of short trouble, power circuit reverts to normal operating state automatically.
Specifically, above-mentioned voltage detection module 11 is made up of resistance R3, R4 for a pair of dividing potential drop and a switch element, but be not limited to this, also can be detected by other element the change in voltage of the power end VCC of the control IC causing because of the short circuit of output, for example, dividing potential drop is not limited to only have a pair of with resistance, and multiple resistance can also be set as required, switch element can utilize other the comparing element with equivalent function to replace, such as comparator etc.In the present embodiment, comparing element adopts the triode TR1 of positive-negative-positive, as shown in Figure 3, one end of resistance R 3 is connected (the A point in figure) with the power end VCC that controls IC, its other end is connected with one end of resistance R 4, the other end ground connection of resistance R 4, and the intermediate point B of two resistance R 3, R4 is connected with the base stage of triode TR1, the emitter of triode TR1 with control the reference voltage terminal REF(figure of IC in be C point) be connected, the collector electrode of triode TR1 is connected with the output of voltage detection module 11.Voltage detection module 11 can also be included in a shunt capacitance C1 who connects between B point and ground GND, and this shunt capacitance C1 plays voltage detecting time delay to a certain degree.Prevent voltage detecting circuit misoperation.
In addition, above-mentioned switch control module 13 is made up of a switch element, in the present embodiment, adopts power field effect transistor TR2, but be not limited to this, can also adopt other element or the combination of element etc. that have with the function of power field effect transistor TR2 equivalence.In the present embodiment, as shown in Figure 3, the grid (being D point in figure) of power field effect transistor TR2 is connected with the input of switch control module 13, keep the output of module 12 to be connected with time delay, the drain electrode of power field effect transistor TR2 is connected (in figure, being E point), the source ground of power field effect transistor TR2 with the output control terminal CS that controls IC.
In addition, above-mentioned time delay keeps module 12 to comprise the discharge resistance R6 and the capacitor C 2 that are connected in parallel, and capacitor C 2 keeps the output of module 12 to be connected with one end of discharge resistance R6 parallel connection with time delay, the other end ground connection that capacitor C 2 is in parallel with discharge resistance R6.In addition, preferably, this time delay keeps module 12 can also between input and output, be connected a charging resistor R5.In the present embodiment, as shown in Figure 3, one end of charging resistor R5 is connected with the collector electrode of triode TR1, above-mentioned one end of the other end and capacitor C 2 and the grid of power field effect transistor TR2 are connected, and utilize the charge constant of this charging resistor R5 and capacitor C 2 to regulate the time of charging to capacitor C 2.In order to ensure the charging current of capacitor C 2, value that can charging resistor R5 is set to much smaller than discharge resistance R6, and wherein, discharge resistance R6 is for discharging to capacitor C 2.In the situation that time delay keeps module 12 not comprise charging resistor R5, this time delay keeps the input of module 12 to be connected with output, that is, above-mentioned one end of capacitor C 2 both kept the input of module 12 to be connected with time delay, kept the output of module 12 to be connected again with time delay.In the present embodiment, in the situation that time delay keeps module 12 not comprise charging resistor R5, above-mentioned one end of capacitor C 2 is connected with the grid of the collector electrode of triode TR1 and power field effect transistor TR2.
Below, with reference to Fig. 3, describe for the course of action of power supply short-circuit protective circuit 1.Output at power supply produces short circuit, and voltage detection module 11 detects the voltage drop that A is ordered, and the voltage that the B obtaining by two resistance R 3, R4 dividing potential drop is ordered also declines.The voltage drop of ordering as B is the B voltage of ordering below 4.4V time to the low 0.6V of voltage of ordering than C below, triode TR1 conducting.Now, the detection that the voltage of the 5V that C is ordered is exported as voltage detection module 11 via triode TR1 judges that signal supply time delay keeps the input of module 12.The voltage of this 5V charges to capacitor C 2 via charging resistor R5, when the voltage at capacitor C 2 two ends be the D voltage of ordering (being equivalent to the switching signal that time delay keeps module 12 to export) be promoted to the power field effect transistor TR2 conducting included higher than switch control module 13 threshold voltage (for example, for 1V) time, power field effect transistor TR2 conducting, make voltage drop that E orders to low level (below 1V), therefore, the control signal of switch control module 13 output low levels, make to control IC and stop output pwm signal, thus, can realize the short-circuit protection of output.
After this, stop output pwm signal owing to controlling IC, control IC power consumption and reduce, simultaneously, the direct voltage obtaining after the ac voltage rectifier of the interchange end from power supply is charged to smoothing capacity C3 via resistance R 1, and the voltage of controlling the power end VCC of IC rises again.Thereupon, the voltage that B is ordered also rises thereupon, and the voltage of ordering as B rises to 4.4V when above, and triode TR1 becomes cut-off from conducting, and now, the voltage that D is ordered is still higher than the on state threshold voltage of power field effect transistor TR2.After this, due to triode TR1 cut-off, the voltage of the 5V being provided by the reference voltage terminal of controlling IC can not supplied with capacitor C 2 via charging resistor R5, so capacitor C 2 is no longer charged, but starts the electric discharge via discharge resistance R6, and the voltage that D order starts decline.The voltage drop of ordering as D is during on state threshold voltage lower than power field effect transistor TR2, power field effect transistor TR2 also ends, and thus, the voltage of controlling the output control terminal CS of IC is that the low level that E is ordered is released, make to control IC output pwm signal again, output current rises again.
In this case, as mentioned above, at the output of power supply still in short-circuit condition, the voltage that B is ordered declines again, make triode TR1 conducting again, after this, make also conducting again of power field effect transistor TR2, the voltage of the output control terminal CS of drop-down control IC, makes to control IC and stops output.Because the output of power supply is always in short-circuit condition, so the output action of above-mentioned starting/closing control IC is proceeded, as shown in Figure 4, the voltage of power end VCC of controlling IC is the wavy rising/decline repeatedly of sawtooth, and the output of power supply is with the cycle output batch (-type) electric current identical with the period of waves of power end VCC that controls IC.Because batch (-type) electric current is only in moment circulation, so the effective value of output current entirety is very low.
At this, can be by keeping the capacitor C 2 of module 12 and the parameter of discharge resistance R6 to regulate to forming time delay in advance, carry out the lasting ON time t1 of regulation power field effect transistor TR2,, in advance regulation makes to control IC and continues to stop the time of output pwm signal, thus the effective value of the batch (-type) electric current of can allocated circuit exporting in the time of short circuit.The size of the value of discharge resistance R6 or capacitor C 2 determines to continue the length of ON time t1, for example, the in the situation that of triode TR1 conducting, the voltage that D is ordered is the voltage that about 5V(approximates the reference voltage terminal REF that controls IC), if discharge resistance R6 is made as to 1M Ω, capacitor C 2 is made as to 1 μ F, and determining lasting ON time t1 is 98.4ms; In the situation that discharge resistance R6 is constant, if capacitor C 2 is made as to 2 μ F, determine that to continue ON time t1 elongated to 160.8ms, that is to say, controlling IC, to continue to stop time of output pwm signal elongated.Thus, reduce the effective value of the batch (-type) electric current that power supply exports in the time of short circuit, further played the protective effect in the time of the output short circuit of power supply.
In the present embodiment, power supply short-circuit protective circuit is by directly the voltage of the power end VCC that controls IC being detected, and whether the output that judges power supply has produced short circuit.But be not limited to this, for example, can also be by the voltage of the feedback end FB that controls IC be detected, carry out the short circuit judgement of the output of power supply.In the present embodiment, receive reference voltage by the reference voltage terminal REF that controls IC, but be not limited to this, also can produce by another way reference voltage.In addition, in the present embodiment, having produced short circuit in the case of detecting the output of power supply, is by being set to low level mode by controlling the output control terminal CS of IC, makes to control IC and stops output pwm signal, but be not limited to this.
Above, execution mode of the present utility model is illustrated.As mentioned above; in the time there is short circuit in the output of power circuit; control IC in power circuit does not possess short-circuit protection function; according to power supply short-circuit protective circuit of the present utility model; can stop the output action of the control IC for carrying out pulse width modulation; significantly reduce the effective value of output current, realize the object of short-circuit protection.In addition; in the leakage inductance due to transformer large or secondary short circuited output impedance is excessive or multiple-output electric power in single output by reasons such as the situations of short circuit; while making short circuit, the variation of power output can not reach the threshold value of an elementary side overpower protection; even so do not start above-mentioned short-circuit protection function in the case of possessing the control IC of short-circuit protection function; can apply equally power supply short-circuit protective circuit of the present utility model, realize reliably the object of short-circuit protection.
In addition, the utility model can carry out various execution modes and distortion not departing under the thought of broad sense of the present utility model and the prerequisite of scope.In addition, above-mentioned execution mode is used for illustrating the utility model, but does not limit scope of the present utility model.
Claims (8)
1. a power supply short-circuit protective circuit, it,, having while producing short circuit for the output of the power supply of the control IC of output pulse width modulation signal, makes described control IC stop output pulse width modulation signal, it is characterized in that,
Comprise:
Voltage detection module, its first input end is connected with the terminal of the voltage of the short-circuit state of the output of detection reflection power supply, the second input is connected with the terminal that receives reference voltage, the result that the voltage that the short circuit of the output based on to described reflection power supply is conditions associated and described reference voltage compare, judge signal from output output detections
Time delay keeps module, and its input is connected with the output of described voltage detection module, judges signal based on described detection, from output output switching signal,
Switch control module, its input keeps the output of module to be connected with described time delay, output is connected with the control terminal that the described control of control IC exported/stopped output pulse width modulation signal, according to the switching signal that keeps module from described time delay, export/stop the signal of output pulse width modulation signal from the described control of the output output control IC being connected with described control terminal;
Described time delay keeps module to judge signal based on described detection, export described switching signal to described switch control module, described switch control module is according to described switching signal, within the delay time that is kept module to specify by described time delay, make described control IC stop output pulse width modulation signal, and, through after described delay time, make described control IC output pulse width modulation signal.
2. power supply short-circuit protective circuit as claimed in claim 1, is characterized in that,
Described voltage detection module has:
Two divider resistances that are connected in series above, the first input end that the upstream extremity that is positioned at the divider resistance of upstream is described voltage detection module, is positioned at the downstream ground connection of the divider resistance in downstream,
The comparing element that the voltage obtaining by described divider resistance dividing potential drop and described reference voltage are compared, first end is connected with the tie point of more than selecting tie point between described two divider resistances that are connected in series above, the second end is the second input of described voltage detection module, the output that the 3rd end is described voltage detection module.
3. power supply short-circuit protective circuit as claimed in claim 2, is characterized in that,
Described voltage detection module also has shunt capacitance, and one end of this shunt capacitance is connected with a tie point of described selection, other end ground connection.
4. the power supply short-circuit protective circuit as described in any one in claim 1～3, is characterized in that,
Described time delay keeps module to comprise the discharge resistance and the electric capacity that are connected in parallel, the first tie point of described discharge resistance and described electric capacity is the output that described time delay keeps module, the second tie point ground connection of described discharge resistance and described electric capacity, described time delay keeps the output of module to keep the input of module to be connected with described time delay.
5. the power supply short-circuit protective circuit as described in any one in claim 1～3, is characterized in that,
Described time delay keeps module to comprise the discharge resistance and the electric capacity that are connected in parallel, the first tie point of described discharge resistance and described electric capacity is the output that described time delay keeps module, the second tie point ground connection of described discharge resistance and described electric capacity, keeps being also connected with charging resistor between the input of module and the output of described time delay maintenance module in described time delay.
6. the power supply short-circuit protective circuit as described in any one in claim 1～3, is characterized in that,
Described switch control module comprises a switch element, the input that the first end of described switch element is described switch control module, the output that the second end is described switch control module, the 3rd end ground connection.
7. power supply short-circuit protective circuit as claimed in claim 1, is characterized in that,
Described voltage detection module comprises two first, second divider resistances that are connected in series and the triode for dividing potential drop, one end of described the first divider resistance is the first input end of described voltage detection module, the other end is connected with one end of described the second divider resistance and the base stage of described triode, the second input of the very described voltage detection module of the transmitting of described triode, the output of the very described voltage detection module of current collection, the other end ground connection of described the second divider resistance
Described time delay keeps module to comprise the discharge resistance and the electric capacity that are connected in parallel, the first tie point of described discharge resistance and described electric capacity is the output that described time delay keeps module, the second tie point ground connection of described discharge resistance and described electric capacity, described time delay keeps the output of module to keep the input of module to be connected with described time delay
Described switch control module comprises a power field effect transistor, and the input that the grid of described power field effect transistor is described switch control module drains as the output of described switch control module, source ground.
8. power supply short-circuit protective circuit as claimed in claim 1, is characterized in that,
Described voltage detection module comprise that two for dividing potential drop are connected in series first, the second divider resistance, a triode and a shunt capacitance, one end of described the first divider resistance is the first input end of described voltage detection module, the other end is connected with one end of described the second divider resistance and the base stage of described triode, the second input of the very described voltage detection module of the transmitting of described triode, the output of the very described voltage detection module of current collection, the other end ground connection of described the second divider resistance, one end of described shunt capacitance is connected with the base stage of described triode, other end ground connection,
Described time delay keeps module to comprise the discharge resistance being connected in parallel, a charging resistor and an electric capacity, the first tie point of described discharge resistance and described electric capacity is the output that described time delay keeps module, the second tie point ground connection of described discharge resistance and described electric capacity, keep being also connected with described charging resistor between the input of module and the output of described time delay maintenance module in described time delay
Described switch control module comprises a power field effect transistor, and the input that the grid of described power field effect transistor is described switch control module drains as the output of described switch control module, source ground.
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| CN201320686546.8U CN203734296U (en) | 2013-11-01 | 2013-11-01 | Power supply short circuit protection circuit |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104466912A (en) * | 2014-11-27 | 2015-03-25 | 矽力杰半导体技术(杭州)有限公司 | Linear voltage regulator with short-circuit protection function |
| WO2016037511A1 (en) * | 2014-09-10 | 2016-03-17 | 广州金升阳科技有限公司 | Power supply protection and control method |
| CN105450017A (en) * | 2015-11-26 | 2016-03-30 | 同济大学 | Time adjustable anti-interference low voltage protection switch circuit |
| WO2016119116A1 (en) * | 2015-01-27 | 2016-08-04 | 华为技术有限公司 | Short circuit protection circuit |
| CN112018730A (en) * | 2020-10-16 | 2020-12-01 | 深圳英集芯科技有限公司 | Switching power supply protection circuit and switching power supply chip |
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2013
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| WO2016037511A1 (en) * | 2014-09-10 | 2016-03-17 | 广州金升阳科技有限公司 | Power supply protection and control method |
| CN104201652B (en) * | 2014-09-10 | 2017-02-15 | 广州金升阳科技有限公司 | Power protection control method |
| CN104466912A (en) * | 2014-11-27 | 2015-03-25 | 矽力杰半导体技术(杭州)有限公司 | Linear voltage regulator with short-circuit protection function |
| CN104466912B (en) * | 2014-11-27 | 2017-08-25 | 矽力杰半导体技术(杭州)有限公司 | A kind of linear voltage regulator with short-circuit protection |
| WO2016119116A1 (en) * | 2015-01-27 | 2016-08-04 | 华为技术有限公司 | Short circuit protection circuit |
| CN105450017A (en) * | 2015-11-26 | 2016-03-30 | 同济大学 | Time adjustable anti-interference low voltage protection switch circuit |
| CN105450017B (en) * | 2015-11-26 | 2018-06-05 | 同济大学 | Time adjustable anti-interference under-voltage protection on-off circuit |
| CN112018730A (en) * | 2020-10-16 | 2020-12-01 | 深圳英集芯科技有限公司 | Switching power supply protection circuit and switching power supply chip |
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