CN203932985U - A kind of battery overcurrent under-voltage protecting circuit - Google Patents
A kind of battery overcurrent under-voltage protecting circuit Download PDFInfo
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- CN203932985U CN203932985U CN201420355311.5U CN201420355311U CN203932985U CN 203932985 U CN203932985 U CN 203932985U CN 201420355311 U CN201420355311 U CN 201420355311U CN 203932985 U CN203932985 U CN 203932985U
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Abstract
The utility model provides a kind of battery overcurrent under-voltage protecting circuit, to solve battery overcurrent under-voltage protecting circuit design complexity in prior art, the technical problem that circuit cost is high.Comprise cell input terminal and input ground, battery output and output ground, and control circuit and NMOS pipe, described control circuit comprises three electronic switches and seven resistance; Wherein, described cell input terminal is connected with described battery output, the source electrode of described NMOS pipe and drain electrode be series at described input and output ground between, the shutoff that described control circuit is controlled described NMOS pipe realizes connection and the disconnection of current supply circuit; By being linked of three electronic switches, when output current be greater than or output voltage lower than set threshold value time, described protective circuit can be cut off current supply circuit and avoid overcurrent and under-voltage infringement with protection battery.This circuit only relies on electronic switch and resistance to realize, and simplicity of design is with low cost, and realizes protection by hardware circuit, and reaction speed is fast.
Description
Technical field
The utility model relates to circuit design field, relates in particular to a kind of battery overcurrent under-voltage protecting circuit.
Background technology
Battery is parts indispensable in electronic product, and the quality of its quality is directly determining the quality good or not of whole electronic product.And inappropriate use battery can cause damage to battery.
To the modal two kinds of situations of the damage of battery, it is exactly overcurrent and under-voltage.Battery is operated under overcurrent and under-voltage state for a long time, can cause irreversible infringement to battery itself.Therefore, protection battery is avoided overcurrent and under-voltage harm, is the problem that hyundai electronics engineer must consider in R & D of complex.And the common complex circuit designs of battery protecting circuit of the prior art, or adopting integrated circuit to add the circuit that peripheral cell forms, circuit cost is high, is all unfavorable for being widely used in electronic product.
Summary of the invention
The embodiment of the present application is by a kind of battery overcurrent under-voltage protecting circuit is provided, to solve battery overcurrent under-voltage protecting circuit design complexity in prior art, the technical problem that circuit cost is high.
For solving the problems of the technologies described above, the embodiment of the present application is achieved by the following technical solutions:
A kind of battery overcurrent under-voltage protecting circuit is provided, comprise cell input terminal and input ground, battery output and output ground, and control circuit and NMOS pipe, wherein, described cell input terminal is connected with described battery output, and the source electrode of described NMOS pipe and drain electrode are series at described input and export between ground, and described control circuit is controlled the conducting of described NMOS pipe and connection and the disconnection that cut-off realizes current supply circuit; Described control circuit comprises the first electronic switch, the second electronic switch and the 3rd electronic switch, and the first resistance, the second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance and the 7th resistance; Wherein,
Described the first resistance and described the second resistance are series between described cell input terminal and described input ground; Described the 3rd resistance and described the 4th resistance are series between described battery output and described output ground; The first end of described the first electronic switch connects the source terminal of described NMOS pipe, and the second end connects described input ground, and the 3rd end connects the first end of described the 6th resistance; The first end of described the 6th resistance is connected in the 3rd end of described the first electronic switch, and the second end is connected in the link of described the 3rd resistance and described the 4th resistance; The first end of described the second electronic switch is connected in the link of described the first resistance and described the second resistance, and the second end connects described cell input terminal, and the 3rd end connects the grid of described NMOS pipe; The first end of described the 5th resistance connects the 3rd end of the second electronic switch, and the second end connects the source electrode of described NMOS pipe; Described the 7th resistance be series at described input and the source terminal of described NMOS pipe between; The first end of described the 3rd electronic switch is connected in the link of described the 3rd resistance and described the 4th resistance, and the second end connects described battery output, and the 3rd end is connected in the link of described the first resistance and described the second resistance.
Further, described the first electronic switch is NPN triode, and its first end is base stage, and the second end is emitter, and the 3rd end is collector electrode; Described the second electronic switch and described the 3rd electronic switch are PNP triode, and wherein, first end is base stage, and the second end is emitter, and the 3rd end is collector electrode.
Further, described the first electronic switch is NMOS pipe, and its first end is grid, and the second end is source electrode, and the 3rd end is drain electrode; Described the second electronic switch and described the 3rd electronic switch are PMOS pipe, and wherein, first end is grid, and the second end is source electrode, and the 3rd end is grid.
Further, the product of the resistance of described the 7th resistance and current protection threshold value is more than or equal to the conducting voltage of described the first electronic switch.
Further, the dividing potential drop of described the first resistance and described the second resistance makes described the first ohmically pressure drop be more than or equal to the conducting voltage of described the second electronic switch, the dividing potential drop of described the 3rd resistance and described the 4th resistance makes described the 3rd ohmically pressure drop be less than the conducting voltage of described the 3rd electronic switch, and the dividing potential drop of described the 3rd resistance and the 6th resistance makes described the 3rd ohmically pressure drop be more than or equal to the conducting voltage of described the 3rd resistance switch.
The embodiment of the present application also provides a kind of battery overcurrent under-voltage protecting circuit, comprise cell input terminal and input ground, battery output and output ground, and control circuit and PMOS pipe, wherein, described input ground is connected with output ground, the source electrode of described PMOS pipe and drain electrode are series between described cell input terminal and battery output, described control circuit is controlled the conducting of described PMOS pipe and connection and the disconnection that cut-off realizes supply access, described control circuit comprises the first electronic switch, the second electronic switch and the 3rd electronic switch, and first resistance, the second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance and the 7th resistance, wherein, described the first resistance and described the second resistance be series at described input and described cell input terminal between, described the 3rd resistance and described the 4th resistance are series between described battery output and described output ground, the first end of described the first electronic switch connects the source terminal of described PMOS pipe, and the second end connects described cell input terminal, and the 3rd end connects the first end of described the 6th resistance, the first end of described the 6th resistance is connected in the 3rd end of described the first electronic switch, and the second end is connected in the link of described the 3rd resistance and described the 4th resistance, the first end of described the second electronic switch is connected in the link of described the first resistance and described the second resistance, and the second end connects described input ground, and the 3rd end connects the grid of described PMOS pipe, the first end of described the 5th resistance connects the 3rd end of the second electronic switch, and the second end connects the source electrode of described PMOS pipe, described the 7th resistance is series between described cell input terminal and the source terminal of described PMOS pipe, the first end of described the 3rd electronic switch is connected in the link of described the 3rd resistance and described the 4th resistance, and the second end connects described output ground, and the 3rd end is connected in the link of described the first resistance and described the second resistance.
Further, described the first electronic switch is PNP triode, and its first end is base stage, and the second end is emitter, and the 3rd end is collector electrode; Described the second electronic switch and described the 3rd electronic switch are NPN triode, and wherein, first end is base stage, and the second end is emitter, and the 3rd end is collector electrode.
Further, described the first electronic switch is PMOS pipe, and its first end is grid, and the second end is source electrode, and the 3rd end is drain electrode; Described the second electronic switch and described the 3rd electronic switch are NMOS pipe, and wherein, first end is grid, and the second end is source electrode, and the 3rd end is grid.
Further, the product of the resistance of described the 7th resistance and current protection threshold value is more than or equal to the conducting voltage of described the first electronic switch.
Further, the dividing potential drop of described the first resistance and described the second resistance makes described the first ohmically pressure drop be more than or equal to the conducting voltage of described the second electronic switch, the dividing potential drop of described the 3rd resistance and described the 4th resistance makes described the 3rd ohmically pressure drop be less than the conducting voltage of described the 3rd electronic switch, and the dividing potential drop of described the 3rd resistance and the 6th resistance makes described the 3rd ohmically pressure drop be more than or equal to the conducting voltage of described the 3rd resistance switch.
Compared with prior art, the technical scheme that the embodiment of the present application provides, the technique effect or the advantage that have are: the battery overcurrent under-voltage protecting circuit that the embodiment of the present application provides, by the first electronic switch, being linked between the second electronic switch and the 3rd electronic switch, when output current is greater than the threshold value of setting, the 7th ohmically electric current increases, make the first electronic switch conducting, by the dividing potential drop of the 3rd resistance and the 6th resistance, the 3rd ohmically pressure drop is increased, the 3rd electronic switch conducting, thereby the second ohmically electric current increases, the first ohmically pressure drop reduces, cause the second electronic switch to disconnect, NMOS pipe disconnects, make circuit automatically cut off current supply circuit and with protection battery, avoid the infringement of overcurrent, when output voltage lower than set threshold value time, the first ohmically pressure drop is reduced, the second electronic switch disconnects, thereby NOMS pipe disconnects, the circuit disconnected current supply circuit of also can autotomying is avoided under-voltage infringement with protection battery, compare with the overcurrent under-voltage protecting circuit of prior art, this circuit only relies on electronic switch and resistance to realize, and simplicity of design is with low cost, and by hardware circuit, realizes protection completely, and reaction speed is fast.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of the battery overcurrent under-voltage protecting circuit of the embodiment of the present application one;
Fig. 2 is the circuit diagram of the battery overcurrent under-voltage protecting circuit of the embodiment of the present application one;
Fig. 3 is the circuit diagram of the battery overcurrent under-voltage protecting circuit of the embodiment of the present application one;
Fig. 4 is the circuit diagram of the battery overcurrent under-voltage protecting circuit of the embodiment of the present application two;
Fig. 5 is the circuit diagram of the battery overcurrent under-voltage protecting circuit of the embodiment of the present application two;
Fig. 6 is the circuit diagram of the battery overcurrent under-voltage protecting circuit of the embodiment of the present application two.
Embodiment
The embodiment of the present application is by a kind of battery overcurrent under-voltage protecting circuit is provided, to solve battery overcurrent under-voltage protecting circuit design complexity in prior art, the technical problem that circuit cost is high; Realized circuit design simple, with low cost, the technique effect that reaction speed is fast.
In order better to understand technique scheme, below in conjunction with Figure of description and concrete execution mode, technique scheme is described in detail.
Embodiment mono-
As the circuit diagram of Fig. 1 battery overcurrent under-voltage protecting circuit that is the embodiment of the present application; comprise cell input terminal Vin and input ground Gin; battery output end vo ut and output ground Gout; and control circuit 10 and NMOS pipe Q4; wherein; cell input terminal Vin is connected with battery output end vo ut, and the source electrode of NMOS pipe Q4 and drain electrode are series between input ground Gin and output ground Gout, and control circuit 10 is controlled the conducting of described NMOS pipe and connection and the disconnection that cut-off realizes discharge loop.
Control circuit 10 comprises the first electronic switch Q1, the second electronic switch Q2 and the 3rd electronic switch Q3, and the first resistance R 1, the second resistance R 2, the three resistance R 3, the four resistance R 4, the five resistance R 5, the six resistance R 6 and the 7th resistance R 7.
The first resistance R 1 and described the second resistance R 2 are series between cell input terminal Vin and input ground Gin; The 3rd resistance R 3 and the 4th resistance R 4 are series between battery output end vo ut and output ground Gout; The first end of the first electronic switch Q1 connects the source terminal of NMOS pipe Q4, and the second end connects described input ground Gin, and the 3rd end connects the first end of the 6th resistance R 6; The first end of the 6th resistance R 6 is connected in the 3rd end of the first electronic switch Q1, and the second end is connected in the link of the 3rd resistance R 3 and the 4th resistance R 4; The first end of the second electronic switch Q2 is connected in the link of the first resistance R 1 and the second resistance R 2, and the second end connects cell input terminal Vin, and the 3rd end connects the grid of NMOS pipe Q4; The first end of the 5th resistance R 5 connects the 3rd end of the second electronic switch Q2, and the second end connects the source electrode of NMOS pipe Q4; The 7th resistance R 7 is series between input ground Gin and the source terminal of NMOS pipe Q4; The first end of the 3rd electronic switch Q3 is connected in the link of the 3rd resistance R 3 and the 4th resistance R 4, and the second end connects battery output end vo ut, and the 3rd end is connected in the link of the first resistance R 1 and the second resistance R 2.
When battery overcurrent does not occur under-voltage time, guarantee not conducting of Q2 conducting Q3, and Q2 conducting meeting makes Q4 conducting, thereby realize the conducting of powered battery path and current supply circuit, guarantee that battery can be normally for electronic product be powered; When output current is greater than the threshold value of setting, the electric current of R7 increases, and the pressure drop on R7 increases, and makes Q1 conducting, by the dividing potential drop of R3 and R6, the pressure drop of R3 is increased, Q3 conducting, thus the electric current on R2 increases, the pressure drop of R1 reduces, cause not conducting of Q2, NMOS pipe disconnects, and makes circuit automatically cut off current supply circuit and with protection battery, avoids the infringement of overcurrent; When output voltage lower than set threshold value time, the pressure drop on R1 is reduced, not conducting of Q2, thereby NOMS pipe disconnects, the circuit disconnected current supply circuit of also can autotomying is avoided under-voltage infringement with protection battery.
The battery overcurrent under-voltage protecting circuit of the embodiment of the present application is compared with the overcurrent under-voltage protecting circuit of prior art; this circuit only relies on three electronic switches and seven resistance to realize; simplicity of design is with low cost, and by hardware circuit, realizes protection completely, and reaction speed is fast.
As shown in Figure 2, the first electronic switch Q1 can be NPN triode, and the second electronic switch Q2 and the 3rd electronic switch Q3 can be PNP triode.
When battery overcurrent does not occur under-voltage time, guarantee Q2 conducting and not conducting of Q3 is by regulating resistance R1, R2, the resistance of R3 and R4 realizes.Generally, the conducting voltage of triode, in 0.7V left and right (specifically the parameter by triode determines), for guaranteeing Q2 conducting, supposes that the voltage of the normal work of battery is 12V, and the resistance of R1 and R2 need to meet:
, make the pressure drop on R1 be more than or equal to 0.7V; For guaranteeing not conducting of Q3, the resistance of R3 and R4 need to meet:
, make the pressure drop on R3 be less than 0.7V; Like this, when Q2 conducting, have electric current to pass through resistance R 5, produce pressure drop on R5, because the grid of NMOS pipe Q4 is connected with the two ends of R5 respectively with source electrode, the pressure drop producing on R5 makes between the grid of Q4 and source electrode satisfied
, as long as the pressure drop on R5 meets the threshold voltage of Q4 conducting, Q4 conducting, Q4 conducting is connected the discharge loop of battery, thus battery can be normally electronic product power supply.Here suppose R2=200
, R4=500
, R1 and R3 value 12.4
, R5 value 5
.
When overcurrent occurs, for example, the overcurrent threshold value of setting is 1A, the now pressure drop in resistance R 7 is greater than and equals 0.7V(and be generally equal to 0.7V), can be so that more than the base stage of Q1 and emitter voltage differ 0.7V, thereby Q1 conducting, after Q1 conducting, the dividing potential drop of R3 and R6 need to make the pressure drop on R3 be more than or equal to 0.7V, thereby make Q3 conducting, after Q3 conducting, electric current on R2 is increased, the pressure drop on R1 reduces, make Q1 change cut-off into from conducting, after Q2 cut-off, on R5, there is no pressure drop, NMOS pipe Q4 cut-off, current supply circuit disconnects, realized the protection to battery overcurrent.Before mention, the dividing potential drop of R3 and R6 need to make the pressure drop on R3 be more than or equal to 0.7V, meanwhile, the dividing potential drop of R3 and R4 also needs to meet and makes the pressure drop on R3 be less than 0.7V, when R4 value 500
, R3 value 12.4
, R6 value 200
can meet above-mentioned condition.
In order to make circuit, be to be adapted to the different battery of voltage, R1 and R3 can be used variable resistor.
It should be noted that the value of R7 is relevant with the threshold current of protective circuit, if R7 is 0.7
, when the electric current on R7 is 1A, the pressure drop on R7 is 0.7V, can meet the condition of Q1 conducting, now, the current protection threshold value of circuit is 1A; If R7 is 1.4
, when the circuit on R7 is 0.5A so, the base stage of Q1 and the pressure reduction of emitter are 0.7V, now, the current protection threshold value of circuit is 0.5A; Visible, by regulating the resistance of the 7th resistance R 7, current protection threshold value that can initialization circuit, makes the protection threshold value of protective circuit controlled.
As shown in Figure 3, the first electronic switch Q1 can manage for NMOS, and the second electronic switch Q2 and the 3rd electronic switch Q3 can manage for PMOS.
When battery overcurrent does not occur under-voltage time, the not conducting of Q3 as long as guarantee Q2 conducting, during this conducting voltage at known PMOS pipe (conventionally can with reference to the parameter handbook of PMOS), can pass through regulating resistance R1, R2, and the resistance of R3 and R4 realizes.The voltage of supposing the normal work of battery is 12V, and for guaranteeing Q2 conducting, the resistance of R1 and R2 need to meet:
be more than or equal to PMOS pipe conducting voltage, make the pressure drop on R1 be more than or equal to PMOS pipe conducting voltage, the voltage being added on PMOS pipe Q2 source electrode is more than or equal to PMOS pipe conducting voltage with the pressure reduction that is added in the voltage on grid, thus Q2 conducting; For guaranteeing not conducting of Q3, the resistance of R3 and R4 need to meet:
be less than PMOS pipe conducting voltage, make the pressure drop on R3 be less than the conducting voltage that PMOS manages Q3, the voltage being added on PMOS pipe Q3 source electrode is less than PMOS pipe conducting voltage with the pressure reduction that is added in the voltage on grid, thus not conducting of Q3; Like this, when Q2 conducting, have electric current to pass through resistance R 5, produce pressure drop on R5, because the grid of NMOS pipe Q4 is connected with the two ends of R5 respectively with source electrode, the pressure drop producing on R5 makes between the grid of Q4 and source electrode satisfied
, as long as the pressure drop on R5 meets the threshold voltage of Q4 conducting, Q4 conducting, Q4 conducting is connected the discharge loop of battery, thus battery can be normally electronic product power supply.
When overcurrent occurs, for example, the overcurrent threshold value of setting is 1A, the now pressure drop in resistance R 7 is greater than the conducting voltage that equals NMOS pipe Q1, the voltage being added on NMOS pipe Q1 grid is more than or equal to the pressure reduction of the voltage on source electrode the conducting voltage that NMOS manages Q1, can be so that Q1 conducting, after Q1 conducting, the dividing potential drop of R3 and R6 need to make the pressure drop on R3 be more than or equal to PMOS pipe conducting voltage, thereby make Q3 conducting, after Q3 conducting, electric current on R2 is increased, the pressure drop on R1 reduces, make Q1 change cut-off into from conducting, after Q2 cut-off, on R5, there is no pressure drop, NMOS pipe Q4 cut-off, current supply circuit disconnects, realized the protection to battery overcurrent.Before mention, the dividing potential drop of R3 and R6 need to make the pressure drop on R3 be more than or equal to PMOS pipe conducting voltage, meanwhile, the dividing potential drop of R3 and R4 also needs to meet the pressure drop making on R3 and is less than PMOS pipe conducting voltage.
In order to make circuit, be to be adapted to the different battery of voltage, R1 and R3 can be used variable resistor.
It should be noted that the value of R7 is relevant with the threshold current of protective circuit, suppose that the conducting voltage of NMOS pipe Q1 is A, if R7 is A
, when the electric current on R7 is 1A, the pressure drop on R7 is AV, can meet the condition of Q1 conducting, now, the current protection threshold value of circuit is 1A; If R7 is 2A
, when the circuit on R7 is 0.5A so, can meet the condition of Q1 conducting, now, the current protection threshold value of circuit is 0.5A; Visible, by regulating the resistance of the 7th resistance R 7, current protection threshold value that can initialization circuit, makes the protection threshold value of protective circuit controlled.
As fully visible; the battery overcurrent under-voltage protecting circuit that the embodiment of the present application provides, by the first electronic switch Q1, being linked between the second electronic switch Q2 and the 3rd electronic switch Q3; and the appropriate value of the first to the 7th resistance, just can realize the under-voltage protection of the overcurrent of battery.When output current is greater than the threshold value of setting, electric current on R7 increases, make Q1 conducting, by the dividing potential drop of R3 and R6, the pressure drop on R3 is increased, Q3 conducting, thereby the electric current on R2 increases, and the pressure drop on R1 reduces, cause Q2 cut-off, NMOS pipe Q4 cut-off, makes circuit automatically cut off current supply circuit and with protection battery, avoids the infringement of overcurrent; When output voltage lower than set threshold value time, the pressure drop on R1 is reduced, Q2 cut-off, thereby NOMS pipe Q4 cut-off, the circuit disconnected current supply circuit of also can autotomying is avoided under-voltage infringement with protection battery; Compare with the overcurrent under-voltage protecting circuit of prior art, this circuit only relies on electronic switch and resistance to realize, and simplicity of design is with low cost, and by hardware circuit, realizes protection completely, and reaction speed is fast.
Embodiment bis-
As the circuit diagram of Fig. 4 battery overcurrent under-voltage protecting circuit that is the embodiment of the present application; comprise cell input terminal Vin and input ground Gin; battery output end vo ut and output ground Gout; and control circuit 10 and PMOS pipe Q4; wherein; input ground Gin is connected with output ground Gout, and source electrode and the drain electrode of NMOS pipe Q4 are series between cell input terminal Vin and battery output end vo ut, and control circuit 10 is controlled the conducting of described PMOS pipe and connection and the disconnection that cut-off realizes discharge loop.
Control circuit 10 comprises the first electronic switch Q1, the second electronic switch Q2 and the 3rd electronic switch Q3, and the first resistance R 1, the second resistance R 2, the three resistance R 3, the four resistance R 4, the five resistance R 5, the six resistance R 6 and the 7th resistance R 7.
The first resistance R 1 and the second resistance R 2 are series between input ground Gin and cell input terminal Vin; The 3rd resistance R 3 and the 4th resistance R 4 are series between output ground Gout and battery output end vo ut; The first end of the first electronic switch Q1 connects the source terminal of PMOS pipe Q4, and the second end connects cell input terminal Vin, and the 3rd end connects the first end of the 6th resistance R 6; The first end of the 6th resistance R 6 is connected in the 3rd end of the first electronic switch Q1, and the second end is connected in the link of the 3rd resistance R 3 and the 4th resistance R 4; The first end of the second electronic switch Q2 is connected in the link of the first resistance R 1 and the second resistance R 2, and the second end connects input ground Gin, and the 3rd end connects the grid of PMOS pipe Q4; The first end of the 5th resistance R 5 connects the 3rd end of the second electronic switch Q2, and the second end connects the source electrode of PMOS pipe Q4; The 7th resistance R 7 is series between cell input terminal Vin and the source terminal of PMOS pipe Q4; The first end of the 3rd electronic switch Q3 is connected in the link of the 3rd resistance R 3 and the 4th resistance R 4, and the second end connects output ground Gout, and the 3rd end is connected in the link of the first resistance R 1 and the second resistance R 2.
When battery overcurrent does not occur under-voltage time, guarantee not conducting of Q2 conducting Q3, and Q2 conducting meeting makes Q4 conducting, thereby realize the conducting of powered battery path and current supply circuit, guarantee that battery can be normally for electronic product be powered; When output current is greater than the threshold value of setting, the electric current of R7 increases, and the pressure drop on R7 increases, and makes Q1 conducting, by the dividing potential drop of R3 and R6, the pressure drop of R3 is increased, Q3 conducting, thus the electric current on R2 increases, the pressure drop of R1 reduces, cause not conducting of Q2, PMOS pipe disconnects, and makes circuit automatically cut off supply access and with protection battery, avoids the infringement of overcurrent; When output voltage lower than set threshold value time, the pressure drop on R1 is reduced, not conducting of Q2, thereby POMS pipe disconnects, the circuit cut-off electric pathway of also can autotomying is avoided under-voltage infringement with protection battery.
The battery overcurrent under-voltage protecting circuit of the embodiment of the present application is compared with the overcurrent under-voltage protecting circuit of prior art; this circuit only relies on three electronic switches and seven resistance to realize; simplicity of design is with low cost, and by hardware circuit, realizes protection completely, and reaction speed is fast.
As shown in Figure 5, the first electronic switch Q1 can be PNP triode, and the second electronic switch Q2 and the 3rd electronic switch Q3 can be NPN triode.
When battery overcurrent does not occur under-voltage time, guarantee Q2 conducting and not conducting of Q3 is by regulating resistance R1, R2, the resistance of R3 and R4 realizes.Generally, the conducting voltage of triode, in 0.7V left and right (specifically the parameter by triode determines), for guaranteeing Q2 conducting, supposes that the voltage of the normal work of battery is 12V, and the resistance of R1 and R2 need to meet:
, make the pressure drop on R1 be more than or equal to 0.7V; For guaranteeing not conducting of Q3, the resistance of R3 and R4 need to meet:
, make the pressure drop on R3 be less than 0.7V; Like this, when Q2 conducting, have electric current to pass through resistance R 5, produce pressure drop on R5, because the source electrode of PMOS pipe Q4 is connected with the two ends of R5 respectively with grid, the pressure drop producing on R5 makes between the source electrode of Q4 and grid satisfied
, as long as the pressure drop on R5 meets the threshold voltage of Q4 conducting, Q4 conducting, Q4 conducting is connected the supply access of battery, thus battery can be normally electronic product power supply.Here suppose R2=200
, R4=500
, R1 and R3 value 12.4
, R5 value 5
.
When overcurrent occurs, for example, the overcurrent threshold value of setting is 1A, the now pressure drop in resistance R 7 is greater than and equals 0.7V(and be generally equal to 0.7V), can be so that more than the emitter of Q1 and base voltage differ 0.7V, thereby Q1 conducting, after Q1 conducting, the dividing potential drop of R3 and R6 need to make the pressure drop on R3 be more than or equal to 0.7V, thereby make Q3 conducting, after Q3 conducting, electric current on R2 is increased, the pressure drop on R1 reduces, make Q1 change cut-off into from conducting, after Q2 cut-off, on R5, there is no pressure drop, PMOS pipe Q4 cut-off, supply access disconnects, realized the protection to battery overcurrent.Before mention, the dividing potential drop of R3 and R6 need to make the pressure drop on R3 be more than or equal to 0.7V, meanwhile, the dividing potential drop of R3 and R4 also needs to meet and makes the pressure drop on R3 be less than 0.7V, when R4 value 500
, R3 value 12.4
, R6 value 200
can meet above-mentioned condition.
In order to make circuit, be to be adapted to the different battery of voltage, R1 and R3 can be used variable resistor.
It should be noted that the value of R7 is relevant with the threshold current of protective circuit, if R7 is 0.7
, when the electric current on R7 is 1A, the pressure drop on R7 is 0.7V, can meet the condition of Q1 conducting, now, the current protection threshold value of circuit is 1A; If R7 is 1.4
, when the circuit on R7 is 0.5A so, the base stage of Q1 and the pressure reduction of emitter are 0.7V, now, the current protection threshold value of circuit is 0.5A; Visible, by regulating the resistance of the 7th resistance R 7, current protection threshold value that can initialization circuit, makes the protection threshold value of protective circuit controlled.
As shown in Figure 6, the first electronic switch Q1 can manage for PMOS, and the second electronic switch Q2 and the 3rd electronic switch Q3 can manage for NMOS.
When battery overcurrent does not occur under-voltage time, the not conducting of Q3 as long as guarantee Q2 conducting, during this conducting voltage at known NMOS pipe (conventionally can with reference to the parameter handbook of NMOS), can pass through regulating resistance R1, R2, and the resistance of R3 and R4 realizes.The voltage of supposing the normal work of battery is 12V, and for guaranteeing Q2 conducting, the resistance of R1 and R2 need to meet:
be more than or equal to NMOS pipe conducting voltage, make the pressure drop on R1 be more than or equal to NMOS pipe conducting voltage, the voltage being added on NMOS pipe Q2 source electrode is more than or equal to NMOS pipe conducting voltage with the pressure reduction that is added in the voltage on grid, thus Q2 conducting; For guaranteeing not conducting of Q3, the resistance of R3 and R4 need to meet:
be less than NMOS pipe conducting voltage, make the pressure drop on R3 be less than the conducting voltage that NMOS manages Q3, the voltage being added on NMOS pipe Q3 source electrode is less than NMOS pipe conducting voltage with the pressure reduction that is added in the voltage on grid, thus not conducting of Q3; Like this, when Q2 conducting, have electric current to pass through resistance R 5, produce pressure drop on R5, because the source electrode of PMOS pipe Q4 is connected with the two ends of R5 respectively with grid, the pressure drop producing on R5 makes between the source electrode of Q4 and grid satisfied
, as long as the pressure drop on R5 meets the threshold voltage of Q4 conducting, Q4 conducting, Q4 conducting is connected the discharge loop of battery, thus battery can be normally electronic product power supply.
When overcurrent occurs, for example, the overcurrent threshold value of setting is 1A, the now pressure drop in resistance R 7 is greater than the conducting voltage that equals PMOS pipe Q1, the voltage being added on PMOS pipe Q1 source electrode is more than or equal to the pressure reduction of the voltage on grid the conducting voltage that PMOS manages Q1, can be so that Q1 conducting, after Q1 conducting, the dividing potential drop of R3 and R6 need to make the pressure drop on R3 be more than or equal to NMOS pipe Q3 conducting voltage, thereby make Q3 conducting, after Q3 conducting, electric current on R2 is increased, the pressure drop on R1 reduces, make Q1 change cut-off into from conducting, after Q2 cut-off, on R5, there is no pressure drop, PMOS pipe Q4 cut-off, supply access disconnects, realized the protection to battery overcurrent.Before mention, the dividing potential drop of R3 and R6 need to make the pressure drop on R3 be more than or equal to NMOS pipe conducting voltage, meanwhile, the dividing potential drop of R3 and R4 also needs to meet the pressure drop making on R3 and is less than NMOS pipe conducting voltage.
In order to make circuit, be to be adapted to the different battery of voltage, R1 and R3 can be used variable resistor.
It should be noted that the value of R7 is relevant with the threshold current of protective circuit, suppose that the conducting voltage of PMOS pipe Q1 is A, if R7 is A
, when the electric current on R7 is 1A, the pressure drop on R7 is AV, can meet the condition of Q1 conducting, now, the current protection threshold value of circuit is 1A; If R7 is 2A
, when the circuit on R7 is 0.5A so, can meet the condition of Q1 conducting, now, the current protection threshold value of circuit is 0.5A; Visible, by regulating the resistance of the 7th resistance R 7, current protection threshold value that can initialization circuit, makes the protection threshold value of protective circuit controlled.
As fully visible; the battery overcurrent under-voltage protecting circuit that the embodiment of the present application provides, by the first electronic switch Q1, being linked between the second electronic switch Q2 and the 3rd electronic switch Q3; and the appropriate value of the first to the 7th resistance, just can realize the under-voltage protection of the overcurrent of battery.When output current is greater than the threshold value of setting, electric current on R7 increases, make Q1 conducting, by the dividing potential drop of R3 and R6, the pressure drop on R3 is increased, Q3 conducting, thereby the electric current on R2 increases, and the pressure drop on R1 reduces, cause Q2 cut-off, PMOS pipe Q4 cut-off, makes circuit automatically cut off supply access and with protection battery, avoids the infringement of overcurrent; When output voltage lower than set threshold value time, the pressure drop on R1 is reduced, Q2 cut-off, thereby POMS pipe Q4 cut-off, the circuit cut-off electric pathway of also can autotomying is avoided under-voltage infringement with protection battery; Compare with the overcurrent under-voltage protecting circuit of prior art, this circuit only relies on electronic switch and resistance to realize, and simplicity of design is with low cost, and by hardware circuit, realizes protection completely, and reaction speed is fast.
It should be noted that; above-mentioned explanation is not to restriction of the present utility model; the utility model is also not limited in above-mentioned giving an example; the variation that those skilled in the art make in essential scope of the present utility model, modification, interpolation or replacement, also should belong to protection range of the present utility model.
Claims (10)
1. a battery overcurrent under-voltage protecting circuit; comprise cell input terminal and input ground; battery output and output ground; and control circuit and NMOS pipe, wherein, described cell input terminal is connected with described battery output; the source electrode of described NMOS pipe and drain electrode are series at described input and export between ground; described control circuit is controlled the conducting of described NMOS pipe and connection and the disconnection that cut-off realizes current supply circuit, it is characterized in that
Described control circuit comprises the first electronic switch, the second electronic switch and the 3rd electronic switch, and the first resistance, the second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance and the 7th resistance; Wherein,
Described the first resistance and described the second resistance are series between described cell input terminal and described input ground; Described the 3rd resistance and described the 4th resistance are series between described battery output and described output ground;
The first end of described the first electronic switch connects the source terminal of described NMOS pipe, and the second end connects described input ground, and the 3rd end connects the first end of described the 6th resistance; The first end of described the 6th resistance is connected in the 3rd end of described the first electronic switch, and the second end is connected in the link of described the 3rd resistance and described the 4th resistance;
The first end of described the second electronic switch is connected in the link of described the first resistance and described the second resistance, and the second end connects described cell input terminal, and the 3rd end connects the grid of described NMOS pipe;
The first end of described the 5th resistance connects the 3rd end of the second electronic switch, and the second end connects the source electrode of described NMOS pipe; Described the 7th resistance be series at described input and the source terminal of described NMOS pipe between;
The first end of described the 3rd electronic switch is connected in the link of described the 3rd resistance and described the 4th resistance, and the second end connects described battery output, and the 3rd end is connected in the link of described the first resistance and described the second resistance.
2. battery overcurrent under-voltage protecting circuit according to claim 1, is characterized in that, described the first electronic switch is NPN triode, and its first end is base stage, and the second end is emitter, and the 3rd end is collector electrode;
Described the second electronic switch and described the 3rd electronic switch are PNP triode, and wherein, first end is base stage, and the second end is emitter, and the 3rd end is collector electrode.
3. battery overcurrent under-voltage protecting circuit according to claim 1, is characterized in that, described the first electronic switch is NMOS pipe, and its first end is grid, and the second end is source electrode, and the 3rd end is drain electrode;
Described the second electronic switch and described the 3rd electronic switch are PMOS pipe, and wherein, first end is grid, and the second end is source electrode, and the 3rd end is grid.
4. battery overcurrent under-voltage protecting circuit according to claim 1, is characterized in that, the product of the resistance of described the 7th resistance and current protection threshold value is more than or equal to the conducting voltage of described the first electronic switch.
5. battery overcurrent under-voltage protecting circuit according to claim 1; it is characterized in that; the dividing potential drop of described the first resistance and described the second resistance makes described the first ohmically pressure drop be more than or equal to the conducting voltage of described the second electronic switch; the dividing potential drop of described the 3rd resistance and described the 4th resistance makes described the 3rd ohmically pressure drop be less than the conducting voltage of described the 3rd electronic switch, and the dividing potential drop of described the 3rd resistance and the 6th resistance makes described the 3rd ohmically pressure drop be more than or equal to the conducting voltage of described the 3rd resistance switch.
6. a battery overcurrent under-voltage protecting circuit; comprise cell input terminal and input ground; battery output and output ground; and control circuit and PMOS pipe, wherein, described input ground is connected with output ground; the source electrode of described PMOS pipe and drain electrode are series between described cell input terminal and battery output; described control circuit is controlled the conducting of described PMOS pipe and connection and the disconnection that cut-off realizes supply access, it is characterized in that
Described control circuit comprises the first electronic switch, the second electronic switch and the 3rd electronic switch, and the first resistance, the second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance and the 7th resistance; Wherein,
Described the first resistance and described the second resistance be series at described input and described cell input terminal between; Described the 3rd resistance and described the 4th resistance are series between described battery output and described output ground;
The first end of described the first electronic switch connects the source terminal of described PMOS pipe, and the second end connects described cell input terminal, and the 3rd end connects the first end of described the 6th resistance; The first end of described the 6th resistance is connected in the 3rd end of described the first electronic switch, and the second end is connected in the link of described the 3rd resistance and described the 4th resistance;
The first end of described the second electronic switch is connected in the link of described the first resistance and described the second resistance, and the second end connects described input ground, and the 3rd end connects the grid of described PMOS pipe;
The first end of described the 5th resistance connects the 3rd end of the second electronic switch, and the second end connects the source electrode of described PMOS pipe; Described the 7th resistance is series between described cell input terminal and the source terminal of described PMOS pipe;
The first end of described the 3rd electronic switch is connected in the link of described the 3rd resistance and described the 4th resistance, and the second end connects described output ground, and the 3rd end is connected in the link of described the first resistance and described the second resistance.
7. battery overcurrent under-voltage protecting circuit according to claim 6, is characterized in that, described the first electronic switch is PNP triode, and its first end is base stage, and the second end is emitter, and the 3rd end is collector electrode;
Described the second electronic switch and described the 3rd electronic switch are NPN triode, and wherein, first end is base stage, and the second end is emitter, and the 3rd end is collector electrode.
8. battery overcurrent under-voltage protecting circuit according to claim 6, is characterized in that, described the first electronic switch is PMOS pipe, and its first end is grid, and the second end is source electrode, and the 3rd end is drain electrode;
Described the second electronic switch and described the 3rd electronic switch are NMOS pipe, and wherein, first end is grid, and the second end is source electrode, and the 3rd end is grid.
9. battery overcurrent under-voltage protecting circuit according to claim 6, is characterized in that, the product of the resistance of described the 7th resistance and current protection threshold value is more than or equal to the conducting voltage of described the first electronic switch.
10. battery overcurrent under-voltage protecting circuit according to claim 6; it is characterized in that; the dividing potential drop of described the first resistance and described the second resistance makes described the first ohmically pressure drop be more than or equal to the conducting voltage of described the second electronic switch; the dividing potential drop of described the 3rd resistance and described the 4th resistance makes described the 3rd ohmically pressure drop be less than the conducting voltage of described the 3rd electronic switch, and the dividing potential drop of described the 3rd resistance and the 6th resistance makes described the 3rd ohmically pressure drop be more than or equal to the conducting voltage of described the 3rd resistance switch.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420355311.5U CN203932985U (en) | 2014-06-30 | 2014-06-30 | A kind of battery overcurrent under-voltage protecting circuit |
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|---|---|---|---|
| CN201420355311.5U CN203932985U (en) | 2014-06-30 | 2014-06-30 | A kind of battery overcurrent under-voltage protecting circuit |
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| CN203932985U true CN203932985U (en) | 2014-11-05 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104037737A (en) * | 2014-06-30 | 2014-09-10 | 青岛歌尔声学科技有限公司 | Current overcurrent and undervoltage protection circuit |
| CN106787083A (en) * | 2016-12-21 | 2017-05-31 | 北京摇光智能科技有限公司 | The control circuit and its control method of a kind of built-in power generation device of smart lock |
-
2014
- 2014-06-30 CN CN201420355311.5U patent/CN203932985U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104037737A (en) * | 2014-06-30 | 2014-09-10 | 青岛歌尔声学科技有限公司 | Current overcurrent and undervoltage protection circuit |
| CN104037737B (en) * | 2014-06-30 | 2017-01-18 | 青岛歌尔声学科技有限公司 | Current overcurrent and undervoltage protection circuit |
| CN106787083A (en) * | 2016-12-21 | 2017-05-31 | 北京摇光智能科技有限公司 | The control circuit and its control method of a kind of built-in power generation device of smart lock |
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