CN104779586A - Battery pack protection circuit, battery pack and electromotive tool - Google Patents
Battery pack protection circuit, battery pack and electromotive tool Download PDFInfo
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- CN104779586A CN104779586A CN201410016568.2A CN201410016568A CN104779586A CN 104779586 A CN104779586 A CN 104779586A CN 201410016568 A CN201410016568 A CN 201410016568A CN 104779586 A CN104779586 A CN 104779586A
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Abstract
The present invention provides a battery pack protection circuit, which is configured to protect a battery pack with N batteries, wherein N is an integer greater than or equal to 2, and the battery pack is provided with an output circuit. The battery pack protection circuit comprises: a switch unit, connected in series in the output circuit; a single battery protection chip, configured to acquire output parameters of the battery pack and control switch-off of the switch unit upon judging that output parameters are not within a preset parameter range; and a power supply module, configured to acquire an output voltage of the battery pack, reduce voltage and supply power to the single battery protection chip. The single battery protection chip originally configured to protect a single battery and the power supply module, matched with each other, are expanded to discharging protection of the battery pack by the battery pack protection circuit, such that the costs of manufacturing and design of the battery pack protection circuit are reduced, the volume increment caused by the battery pack protection circuit is avoided, and very high market value is realized. In addition, the present invention provides a battery pack applying the protection circuit and an electromotive tool.
Description
Technical field
The present invention relates to a kind of power brick protective circuit, the power brick applying this power brick protective circuit and electric tool.
Background technology
In recent years, along with the development of battery material technology, the capacity of battery is significantly promoted, and its range of application also extends to some powerful power category electric devices, as electric tool etc. from some low power electrical type electric devices.Like this, the electric tool that have employed high-multiplying-power battery can be broken away from the constraint of cable and can use at any time, everywhere.For increasing operation rate, what these batteries adopted usually is rechargeable battery, as NI-G (Nickel-cadmium, NiCd) battery, ni-mh (Nickel-Metal Hydride, NiMH) battery, lithium ion (Lithium-ion, L-ion) battery etc.
The battery of the above-mentioned type is when with electric tool cooperating, be in a discharge condition, during battery discharge, when voltage drop should not continue to battery lowest starting voltage value (final voltage) discharged again, also continuing electric discharge just may cause inner pressure of battery to raise, the invertibity of positive and negative electrode active material is damaged, thus the capacity of battery can be made to produce obviously minimizing; Meanwhile, during battery discharge, when battery instantaneous output current is excessive and when exceeding maximum operating currenbt (the termination electric current) that should not continue again to discharge, also continue electric discharge can cause equally battery with the use of electric tool in the damage of electric device.Therefore, in the design process of these electric tools, all can consider to adopt the combination of hardware or hardware and software to carry out putting to power brick or the protection of overcurrent.
Existing power brick, in order to improve capacity, is generally built-in with multiple batteries.When design has the power brick discharge protection circuit of multiple batteries, conventional means has two kinds, one is in every batteries, all connect a monocell protect IC, as long as wherein a batteries occurred putting or overcurrent condition time, just stop the electric discharge of whole power brick, this salvo, make the quantity of monocell protect IC more, cause power brick protective circuit volume larger, the power brick or the electric device volume and weight that cause accommodating power brick protective circuit are all larger, add the difficulty of carrying, add the design cost of power brick protective circuit simultaneously, another kind of means are, integrated microprocessor (MCU) is adopted to gather the output voltage of whole power brick and output current and judge whether this output voltage or output current meet demand, and then realize protecting the electric discharge of whole power brick, but the integrated level of microprocessor (MCU) is higher, the independent mistake for power brick put or overcurrent protection time, lower except excessively putting with other functional utilization rates except over-current detection, and due to the restriction of microprocessor processing technology, its cost occupies Gao Bu little always, microprocessor (MCU) is very meticulous simultaneously, also very high to its operating environment requirements, be unfavorable for applying of this kind of battery protecting circuit.
Therefore, be necessary that proposing a kind of new power brick protective circuit solves the problems referred to above.
Summary of the invention
The invention provides a kind of battery protecting circuit, it can make power brick safe-discharge, and Design and manufacture cost is lower.
To achieve the above object of the invention, the invention provides a kind of power brick protective circuit, for the protection of the power brick with N batteries, N be more than or equal to 2 integer, described power brick has output circuit, wherein, described power brick protective circuit comprises: switch element, is series in described output circuit; Monocell protect IC, for obtaining the output parameter of described power brick, judges whether described output parameter is positioned at preset parameter range, if not, controls described switch element and disconnects, if so, keep described switching means conductive; Supply module, for obtaining the output voltage of power brick, powers to after doing step-down process to described output voltage described monocell protect IC.
As a further improvement on the present invention, described output parameter comprises output voltage, and described preset parameter range comprises predetermined voltage range, and described power brick protective circuit also comprises: voltage transformation module, for obtaining the output voltage of described power brick; Step-down process is done to described output voltage, and exports sampling voltage; Described monocell protect IC, for obtaining described sampling voltage; Judge whether described sampling voltage is positioned at described predetermined voltage range, if not, control described switch element and disconnect, if so, keep described switching means conductive.
As a further improvement on the present invention, described sampling voltage is the 1/N of described output voltage.
As a further improvement on the present invention, described supply module exports starting resistor to after the step-down of power brick output voltage, and described sampling voltage equals described starting resistor.
As a further improvement on the present invention, described power brick protective circuit comprises for bleeder circuit or the step-down chip simultaneously as supply module and voltage transformation module.
As a further improvement on the present invention; described monocell protect IC comprises the chip that model is S8261-C; described S8261-C chip comprises positive and negative power input terminal; described negative supply input terminal ground connection is arranged, and described positive supply input terminal connects the output of described bleeder circuit or step-down chip.
As a further improvement on the present invention, described switch element comprises N channel field-effect pipe, and described S8261-C chip comprises control of discharge splicing ear, and described control of discharge splicing ear connects the grid of described N channel field-effect pipe.
As a further improvement on the present invention, described output parameter comprises output current, and described preset parameter range comprises predetermined current scope, and described power brick protective circuit also comprises: current detection module, for detecting the output current of power brick; Described monocell protect IC is also for obtaining described output current; Judge whether described output current is positioned at described predetermined current scope, if not, control described switch element and disconnect, if so, keep described switching means conductive.
As a further improvement on the present invention, described current detection module comprises: sampling resistor, and described output current flows through described sampling resistor; Described monocell protect IC comprises voltage detection terminal, and described sampling resistor one end ground connection is arranged, and the other end is connected to described voltage detection terminal.
As a further improvement on the present invention, described power brick protective circuit also comprises: reference voltage generation module, exports a reference voltage; Voltage comparator, comprises positive and negative input pin and an output pin, and described negative input pin connects reference voltage generation module, and described positive input pin obtains the output voltage of described power brick, and described output pin is connected to described switch element; When the input voltage of described power brick is greater than described reference voltage, described output pin controls described switch element and disconnects, otherwise described output pin keeps described switching means conductive.
Present invention also offers one can safe-discharge, and the lower-cost power brick of Design and manufacture.
To achieve the above object of the invention, the invention provides a kind of power brick, carry out electric discharge think that it provides electric power for being connected with electric tool, wherein, described power brick comprises: housing; N batteries, is contained in described housing, N be more than or equal to 2 integer; And the power brick protective circuit as described in foregoing summary, be contained in described housing, described power brick has output circuit, and described power brick protective circuit connects described output circuit.
Present invention also offers a kind of power brick safe-discharge of use that can make to be mated, and Design and manufacture lower-cost electric tool.
To achieve the above object of the invention, the invention provides and can be connected with the power brick with multiple batteries, wherein, described electric tool comprises: device body, comprise casing, the motor be accommodated in casing, by described motor-driven working head, for installing the Plug Division of power brick, described Plug Division obtains the electric power of described power brick and is passed to described motor after installation power brick; And the power brick protective circuit as described in foregoing summary, described power brick protective circuit is arranged in described casing.
Compared with prior art; power brick protective circuit provided by the present invention, the power brick applying this power brick protective circuit and electric tool; by by originally to coordinate with supply module for the protection of the monocell protect IC of monocell extend to the power brick with multiple batteries discharge prevention among; effectively control manufacture and the design cost of power brick protective circuit simultaneously; and the increase of power brick protective circuit volume can not be brought, there is very strong market value.
Accompanying drawing explanation
Above-described object of the present invention, technical scheme and beneficial effect by the detailed description that can realize specific embodiments of the invention below, can describe and clearly obtain simultaneously by reference to the accompanying drawings.
Fig. 1 is the circuit block diagram that in first embodiment of the invention, power brick works after being plugged into electric tool.
Fig. 2 is the circuit block diagram that in second embodiment of the invention, power brick works after being plugged into electric tool.
Related elements reference numeral in diagram is as follows:
Power brick protective circuit, 10a, 10b voltage comparator, 14
Switch element, 11 power brick, 20
Supply module, 12a output circuit, 21
Voltage transformation module, 12b sampling resistor, 22
Monocell protect IC, 13
Embodiment
Describe the present invention below with reference to embodiment shown in the drawings.But these execution modes do not limit the present invention, the structure that those of ordinary skill in the art makes according to these execution modes, method or conversion functionally are all included in protection scope of the present invention.
Shown in ginseng Fig. 1; in the first embodiment of the present invention, power brick protective circuit 10a, it can coordinate in the process of carrying out discharging with electric tool (not shown) in power brick 20; prevent the electric discharge of power brick 20 abnormal, guarantee the safety with electric device in power brick 20 and electric tool.
It should be noted that, the electric discharge of power brick 20 as herein described is abnormal, and the mistake referring to power brick 20 is put, overcurrent and temperature cross the high situation easily causing power brick 20 and connect that with it element is damaged.
In the present embodiment, power brick 20 comprises housing, contains the lithium ion battery of the mutual series connection of N joint in housing, N be more than or equal to 2 integer, power brick 20 also comprises all batteries of electric connection and the lead-out terminal of extensional shell periphery, and lead-out terminal comprises positive and negative electrode terminal.
It should be noted that, the general name of lithium ion battery as herein described to be negative material the be rechargeable battery of elemental lithium, according to the difference of positive electrode, it can form many systems, as " manganese lithium " battery, " lithium iron " battery etc.; Simultaneously according to the different demands of operating mode, the type of battery, joint number and set-up mode also visual concrete condition and different, in addition, due to the characteristic difference of battery, the discharge voltage lower limit of its correspondence, the discharging current upper limit all can corresponding differences, do not repeat at this.
In the present embodiment, electric tool comprises device body, device body comprises casing, be accommodated in motor in casing and by motor-driven working head, working head can be drill bit, screwdriver bit, saw blade etc., and corresponding electric tool can be electric drill, screwdriver or annular saw etc.
Device body comprises the Plug Division for installing power brick 20, and after power brick 20 is mounted to this Plug Division, Plug Division obtains the electric power of power brick 20 and by power delivery to motor, makes electric machine rotation, and then drives working head.
Concrete, the conducting terminal for connecting with the lead-out terminal of power brick 20 is contained in Plug Division, device body also comprises the trigger extending to casing periphery, and trigger is series between conducting terminal and motor, for cut off or conducting is passed to the supply of electric power of motor by power brick 20.
Preferably, power brick 20 and the connected mode of Plug Division comprise the mounting meanss such as oblique slot type is connected, buckle-type connection, and after only needing to ensure that power brick 20 and Plug Division interfix, lead-out terminal and conducting terminal are electrically connected.
Power brick 20 has output circuit 21, and output circuit 21 is for transmitting the electric power of power brick in electric tool.In the present embodiment, output circuit 21 comprises the power transmission line in power brick 20 in each battery to electric tool motor.
In the present embodiment, power brick protective circuit 10a comprises switch element 11, supply module 12a and monocell protect IC 13.
Wherein, power brick protective circuit 10a be fixed on electric tool casing among and the output circuit 21 connecting power brick 20 is positioned at the part of electric tool.
Switch element 11 be connected serially to be positioned at electric tool casing output circuit 21 among, when power brick 20 occurs that electric discharge is abnormal, power brick protective circuit 10a is disconnected by control switch unit 11, the safety of available protecting power brick 20.
Certainly; in other embodiments of the present invention; power brick protective circuit 10a also can be built in the housing of power brick 20; only need to make switch element 11 be connected serially among the output circuit 21 of the housing being positioned at power brick 20; this is technology well known to those of ordinary skill in the art, and therefore not to repeat here.
Certainly, battery protecting circuit 10 also comprises the common element such as filter capacitor, voltage-stabiliser tube being parallel to switch element 11 both sides, for the voltage of the electric current and switch element 11 two ends that steadily enter switch element 11, ensures the safe handling of switch element 11.
Supply module 12a connects the output circuit of power brick 20; and then obtain the output voltage of power brick 20; supply module 12a carries out step-down process to this output voltage in advance; and export starting resistor; by being loaded on monocell protect IC 13 by less starting resistor, the monocell protect IC 13 that originally only can be applied to protection single battery can be applied among power brick 20.
By power supply circuits 12a, the output voltage originally exceeding the power brick 20 of monocell protect IC 13 starting resistor is carried out step-down process, monocell protect IC 13 can be protected power brick 20, improve the scope of application of monocell protect IC 13.And monocell protect IC 13 and power supply circuits 12a are ripe element, and cost is lower, effectively ensure that the design of power brick protective circuit 10a, manufacturing cost.
In the present embodiment, power brick 20 has output parameter, the various electric discharge abnormalities of the corresponding aforementioned power brick 20 of output parameter, and such as, when power brick 20 was in and puts state, output parameter corresponded to output voltage; When power brick 20 is in over-current state, output parameter corresponds to output current; Preset preset parameter range, when output parameter is not at preset parameter range, power brick 20 is in its electric discharge abnormality, thus by monitoring output parameter, intuitive judgment can go out power brick 20 and whether be in electric discharge abnormality, to ensure the safe-discharge of power brick 20.
Concrete, monocell protect IC 13 connects the output circuit of power brick 20, obtains the output parameter of power brick 20, when the output parameter of power brick 20 is positioned at preset parameter range, now, power brick 20 is in safe-discharge state, the conducting of monocell protect IC 13 maintained switch unit 11; Otherwise if when output parameter is not positioned at preset parameter range, power brick 20 is in electric discharge abnormality, and control switch unit 11 disconnects by monocell protect IC 13, the safety of element avoided power brick 20 and connect with it.Such as, when monocell protect IC 13 is for preventing power brick 20 from excessively putting, the output voltage of monocell protect IC 13 direct-detection power brick 20, and then judge whether power brick 20 puts excessively by output voltage.
In the present embodiment; power brick 20 is protected with coordinating of monocell protect IC 13 by supply module 12a; instead of existing multiple batteries protect IC or the higher microprocessor (MCU) of integrated level and the more much higher battery protection chip of cost; reduce the Design and manufacture cost of power brick protective circuit 10a; and the increase of power brick protective circuit 10a volume can not be brought, there is very strong market value.
In the present embodiment, the output parameter of power brick 20 comprises output voltage, corresponding, preset parameter range comprises predetermined voltage range.Monocell protect IC 13 detects the output voltage of power brick 20, realizes power brick 20 Cross prevention.
Power brick protective circuit 10a also comprises voltage transformation module 12b, when monocell protect IC 13 detects the output voltage of power brick 20, for carrying out step-down process to the output voltage of power brick 20, and exports sampling voltage.Due to when in power brick 20, battery number is too much; the output voltage of power brick 20 can easily exceed the detection voltage range of monocell protect IC 13; during the output voltage of monocell protect IC 13 direct-detection power brick 20, monocell protect IC 13 is easily caused to be damaged.Preferably, monocell protect IC 13 obtains the sampling voltage that voltage transformation module 12b exports, thus avoids battery number in power brick 20 more, causes all kinds of monocell protect IC 13 cannot be general, improves power brick protective circuit 10a versatility.
Preferably, voltage transformation module 12b is bleeder circuit, and bleeder circuit comprises the first divider resistance of being arranged in series and the second divider resistance, is connected the input of the first divider resistance, connects the earth terminal of the second divider resistance and the output between the first divider resistance and the second divider resistance.The input of bleeder circuit connects a conducting terminal in electric tool, when power brick 20 pairs of electric tools are powered, obtains the output voltage of power brick 20; The output of bleeder circuit is connected to monocell protect IC 13.By setting the resistance value ratio of the first divider resistance and the second divider resistance, can the sampling voltage of output of setting voltage modular converter 12b and the ratio of the output voltage of power brick 20.
Certainly, in other embodiments of the present invention, voltage transformation module 12b also can be step-down chip, only needs guarantee to reach step-down object, does not repeat at this.
In the present embodiment, be built-in with 4 joint lithium ion batteries in power brick 20, the conversion proportion of voltage transformation module 12b is 1/4.Obtain the output voltage of power brick 20 at voltage transformation module 12b after; the output voltage of power brick 20 is reduced for numerical value is its sampling voltage of 1/4; because the dividing ratios of voltage transformation module 12b becomes reciprocal relation with number of batteries in power brick 20; now; sampling voltage can wait the output voltage being all single battery in power brick 20, the versatility of bonding battery protection chip 13.
According to the requirement of the discharge voltage of lithium ion battery safe handling in power brick 20, the discharge voltage lower limit of single-unit lithium ion battery can be obtained, and then confirm predetermined voltage range.Under the output voltage of power brick 20 is less than discharge voltage in limited time, now output voltage is not positioned at predetermined voltage range, and power brick 20 was in the state of putting.Before use monocell protect IC 13 carries out power brick protection, debug monocell protect IC 13 in advance, the discharge voltage lower limit of single lithium battery is set to its predeterminated voltage.
Monocell protect IC 13, after the sampling voltage of output obtaining voltage transformation module 12b, judges whether sampling voltage is less than predeterminated voltage, if be less than predeterminated voltage, then shows that now to one's heart's content condition had appearred in single battery in power brick 20.Because the discharge voltage upper limit of sampling voltage and the output voltage of power brick 20 and the discharge voltage upper limit of monocell and power brick is geometric ratio relation, can show whether the output voltage of power brick 20 is less than the discharge voltage upper limit of whole power brick equally, and then infer whether power brick 20 also occurred to one's heart's content condition.
In the present embodiment, monocell protect IC 13 and voltage transformation module 12b all have ripe design, while guarantee power brick 20 Cross prevention precision, effectively reduce power brick protective circuit 10a design and manufaction cost.
Monocell protect IC 13 and switch element 11 are electrically connected; after monocell protect IC 13 judges that sampling voltage is less than predeterminated voltage; monocell protect IC 13 exports an electric voltage exception signal to switch element 11; based on this electric voltage exception signal; switch element 11 disconnects; output circuit 21 is also disconnected, and the mistake avoiding power brick 20 is put, the available protecting safety of power brick 20.
In the present embodiment, it is same value that the voltage of configuration supply module 12a and voltage transformation module 12b reduces ratio, and the starting resistor that supply module 12a is exported is equal with the sampling voltage that voltage transformation module 12b exports.Thus supply module 12a and voltage transformation module 12b can use same classification bleeder circuit or step-down chip, reduce the element buying of power brick protective circuit 10a and change difficulty, being conducive to the large-scale production of power brick protective circuit 10a.
Preferably, supply module 12a and voltage transformation module 12b adopts same bleeder circuit or step-down chip, while bonding battery protection chip 13 steady operation, reduces the Design and manufacture cost of power brick protective circuit 10a.
In the present embodiment; in power brick 20, the rated voltage of lithium battery is 3.6 volts; monocell protect IC 13 includes but not limited to that model is the chip of S8261-C; S8261-C chip has with low cost, applied range, the advantage low to operating environment requirements, is usually used in overvoltage or the overcurrent protection of power brick 20.
High relative to integrated level conventional in present battery bag protective circuit, the microprocessor (MCU) of complete function, S8261-C chip fully can meet the functional requirement in present battery bag Cross prevention, avoid microprocessor (MCU) bring the shortcoming that function is superfluous, energy consumption is too high, working condition requirement is high; Meanwhile, the structure of S8261-C chip is simple, production capacity very big, ensure that production and the maintainability of power brick protective circuit 10a, is convenient to form scale competitive advantage, enhances the market competitiveness of power brick protective circuit 10a.
The starting resistor of S8261-C chip is obtained as difference by the upper voltage of positive voltage input terminal (VDD) and negative voltage input terminal (VSS), S8261-C chip has operating voltage range, when starting resistor is positioned at this operating voltage range, namely when the starting resistor being loaded on S8261-C chip is greater than its minimum operating voltage, S8261-C chip is in starting state, otherwise, when starting resistor is not positioned at this operating voltage range, namely, when the starting resistor being loaded on S8261-C chip is less than its minimum operating voltage, S8261-C chip quits work.
In the present embodiment, on S8261-C chip, negative supply input terminal (VSS) ground connection is arranged, as the output of the step-down chip of supply module 12a and voltage transformation module 12b while that the positive supply input terminal (VDD) of S8261-C chip connecting aforementioned, the sampled voltage that the starting resistor of now supply module 12a output and voltage transformation module 12b export is equal, by predetermined voltage range being set as the operating voltage range of S8261-C chip, when sampling voltage is positioned at predetermined voltage range, deducibility goes out, starting resistor is also positioned at operating voltage range, S8261-C chip is in its starting state.
In the present embodiment, switch element 11 comprises N channel field-effect pipe, and the control of discharge splicing ear (DO) of S8261-C is connected to the grid of the N channel field-effect pipe as switch element 11.When the voltage of the positive supply input terminal (VDD) being loaded on S8261-C chip is greater than its minimum operating voltage, in S8261-C chip and power brick 20, lithium ion battery all normally works, the control of discharge splicing ear (DO) of S8261-C exports continuation high level, after obtaining this continuation high level signal as the grid of the N channel field-effect pipe of switch element 11, continuation conducting, makes power brick 20 pairs of electric tools power.
Otherwise when the voltage of the positive supply input terminal (VDD) being loaded on S8261-C chip is less than its minimum operating voltage, in power brick 20, lithium ion battery belonged to the state of putting.Now; the starting resistor of S8261-C chip does not reach its work requirements; to quit work; its control of discharge changes with splicing ear (DO) and exports continuation low level; after obtaining this continuation low level signal as the grid of the N channel field-effect pipe of switch element 11; switch element 11 disconnects, and stops power brick 20 pairs of electric tools to power, thus in protection power brick 20, each joint lithium ion battery no longer continued to put.
By by equal with sampling voltage for starting resistors different for object setting; simultaneously by the operating voltage range of monocell protect IC 13 and predetermined voltage range unification; while bonding battery protection chip 13 pairs of power brick 20 Cross prevention effects, make the structure of power brick protective circuit 10a simpler, compact.
Certainly, in other embodiments of the present invention, switch element 11 also can comprise P-channel field-effect transistor (PEFT) pipe, corresponding, only auxiliary circuit need be set between the control of discharge splicing ear (DO) of S8261-C and the grid of P-channel field-effect transistor (PEFT) pipe, make the output of control of discharge splicing ear (DO) change to continuation high level signal, switch element can be made equally to disconnect, this is technology well known to those of ordinary skill in the art, and therefore not to repeat here.
Certainly, in other embodiments of the present invention, switch element 11 also can comprise other electronic switch types, is not limited to aforementioned field effect type, and this is technology well known to those of ordinary skill in the art, does not repeat at this.
In the present embodiment, the output parameter of power brick 20 also comprises output current, corresponding, preset parameter range comprises predetermined current scope.Monocell protect IC 13 detects the output current of power brick 20, realizes power brick 20 overcurrent protection.
According to the discharging current requirement of lithium ion battery safe handling in power brick 20, the discharging current upper limit of single-unit lithium ion battery can be obtained, and then confirm predetermined current scope.Be greater than on discharging current at the output current of power brick 20 and prescribe a time limit, now output current is not positioned at predetermined current scope, and power brick 20 is in over-current state.Before use monocell protect IC 13 carries out power brick protection, debug monocell protect IC 13 in advance, the discharging current upper limit is set to its predetermined current.
In the present embodiment; power brick protective circuit 10a also has current detection module (not shown); it to be connected in the output circuit 21 of power brick 20 and to obtain the output current of power brick 20, and then is passed in monocell protect IC 13 by the output current of power brick 20.Judging that the output voltage of power brick 20 is positioned at its predeterminated voltage parameter; namely when putting did not appear in power brick 20; when monocell protect IC 13 judges whether the output current of power brick 20 is positioned at its predetermined current, and then determine whether power brick 20 occurs overcurrent condition.If judge there is overcurrent in power brick 20, and monocell protect IC 13 pairs of switch elements 11 export a current anomaly signal, make switch element 11 disconnect equally.
In the present embodiment, current detection module comprises the sampling resistor 22 of the end being positioned at output circuit 21, and one end ground connection of sampling resistor 22 is arranged, among other end access output circuit 21; And the ungrounded end of sampling resistor 22 is connected to the voltage detection terminal (Vm) of S8261-C chip, due to sampling resistor 22 one end ground connection, voltage detection terminal (Vm) can directly obtain magnitude of voltage on sampling resistor 22.By pre-setting the resistance value of sampling resistor 22, infer the output current of power brick 20 by magnitude of voltage on sampling resistor 22, to realize judging power brick 20 whether overcurrent.
Certainly, the mode obtaining the output current of power brick 20 is not limited to the mode of the sampling resistor 22 that aforementioned employing ground connection is arranged, and this is technology well known to those of ordinary skill in the art, does not repeat at this.
In the present embodiment, S8261-C chip and the switch element 11 coordinating this chip to use and voltage transformation module 12b are common discrete function element; Power brick protective circuit 10a, by aforementioned all discrete function element and S8261-C chip being jointly arranged on one piece of circuit board, making the design technology of power brick protective circuit 10a simpler, is convenient to its large-scale production.Simultaneously; the size of S8261-C chip is less; by each discrete component on arrangement circuit board; effectively can ensure that the volume of power brick protective circuit 10a can not be excessive; make power brick protective circuit 10a can adapt to current application power brick or electric tool widely, improve the practicality of power brick protective circuit 10a.
Certainly; in other embodiments of the present invention, aforementioned output parameter also to can be in the output voltage of power brick 20 and output current one, and power brick protective circuit 10a only protects the mistake of power brick 20 to put or overcurrent; this is technology well known to those of ordinary skill in the art, does not repeat at this.
Compared with prior art, in the present embodiment power brick protective circuit 10a, can complete and the mistake of the power brick with multiple batteries is put and overcurrent protection, in Cross prevention process, by cost is lower and preparation technology, the monocell protect IC 13 that expansion effect is all very strong and supply module 12a, voltage transformation module 12b matches, power brick 20 output voltage larger for script voltage range is reduced for lower single battery voltage is compared judgement, while ensureing that power brick is crossed and put judgment accuracy, improve the versatility of monocell protect IC 13, effectively reduce the manufacturing cost of power brick protective circuit 10a, volume does not have a larger increase simultaneously, ensure that the scope of application of power brick protective circuit, there is very strong market value.
Shown in ginseng Fig. 2; the power brick protective circuit 10b that the second embodiment of the present invention provides; with the first embodiment unlike; power brick protective circuit 10b protects the overcurrent of power brick 20 by monocell protect IC 13; protect the mistake of power brick 20 to put by voltage comparator 14, it is relatively independent for wherein protecting power brick 20 overcurrent and crossing the element put.The following specifically describes monocell protect IC 13 protect power brick 20 overcurrent respectively with comparator 14 and cross the process of putting.
In the present embodiment, the output parameter of power brick 20 is only the output current of power brick 20, and monocell protect IC 13 detects the output current of power brick 20, by judging whether output current is positioned at predetermined current scope and judges power brick 20 whether overcurrent.Concrete, monocell protect IC 13 judges whether the output current of power brick 20 is greater than the higher limit of predetermined current scope, judges power brick whether overcurrent.
Wherein, power brick protective circuit 10b adopts current detection module as described in the first embodiment (not shown) to gather the output current of power brick 20; and then the output current of power brick 20 is directly passed in monocell protect IC 13; when monocell protect IC 13 judges that the output current of power brick 20 is greater than predetermined current, can show that overcurrent condition appears in power brick 20.Now, monocell protect IC 13 pairs of switch element 11 output current abnormal signals, make switch element 11 disconnect.
In the present embodiment, monocell protect IC 13 includes but not limited to that model is the chip of S8261-C, and S8261-C chip has with low cost, applied range, the advantage low to operating environment requirements, reduces power brick protective circuit 10b and designs and maintenance cost.
High relative to integrated level conventional in present battery bag protective circuit, the microprocessor (MCU) of complete function, S8261-C chip fully can meet the functional requirement in present battery bag Cross prevention, avoid microprocessor (MCU) bring the shortcoming that function is superfluous, energy consumption is too high, working condition requirement is high; Meanwhile, the structure of S8261-C chip is simple, production capacity very big, ensure that production and the maintainability of power brick protective circuit 10b, is convenient to form scale competitive advantage, enhances the market competitiveness of power brick protective circuit 10b.
Describe with in the first embodiment, switch element 11 is also N channel field-effect pipe, the control of discharge splicing ear (DO) of S8261-C is connected to the grid of the N channel field-effect pipe as switch element 11, when detecting that overcurrent appears in power brick 20, control of discharge splicing ear (DO) exports the grid of continuation low level signal to N channel field-effect pipe, switch element 11 is disconnected, thus realizes the disconnection of output circuit 21.
In the present embodiment; power brick protective circuit 10b also comprises supply module 12a; supply module 12a is for obtaining the output voltage of power brick 20 and exporting starting resistor after being reduced by this output voltage; this starting resistor is loaded on the positive supply input terminal (VDD) of monocell protect IC 13, makes monocell protect IC 13 keep starting.
Negative supply input terminal (VSS) ground connection of monocell protect IC 13 is arranged; with the first embodiment unlike; in the present embodiment; supply module 12a includes but not limited to three-terminal voltage-stabilizing chip; according to the specified starting resistor of monocell protect IC 13; the output voltage presetting three-terminal voltage-stabilizing chip is the specified starting resistor of monocell protect IC 13; and this output voltage is loaded on the positive supply input terminal (VDD) of monocell protect IC 13, monocell protect IC 13 is worked under rated voltage drives.
In the present embodiment; power brick protective circuit 10b also comprises voltage comparator 14; voltage comparator 14 comprises positive and negative input pin, an output pin and feeder ear; feeder ear obtains the output voltage of power brick; carry out the specified starting resistor of formation voltage comparator 14 after step-down process, output pin is connected to switch element 11.
The positive input pin of voltage comparator 14 connects the output of power brick 20, and then obtains the output voltage of power brick 20; Negative input pin connects a reference voltage generation module (not shown).Power brick 20 has discharge voltage lower limit, the output voltage of power brick 20 to be less than under this discharge voltage in limited time, power brick 20 was in the state of putting, by being arranged among reference voltage generation module by the discharge voltage lower limit of power brick 20, reference voltage generation module output voltage is made to equal the discharge voltage lower limit of power brick 20.Under the output voltage of power brick 20 is less than its discharge voltage in limited time, the voltage being loaded on the positive input pin of voltage comparator 14 is less than the voltage being loaded on its negative input pin, now voltage comparator 14 output low level signal is to the grid as the N channel field-effect pipe of switch element 11, N channel field-effect pipe is after acquisition low level signal, automatic disconnection, thus the disconnection realizing output circuit 21.Corresponding, under the output voltage of power brick 20 is greater than its discharge voltage in limited time, the voltage being loaded on the positive input pin of voltage comparator 14 is greater than the voltage being loaded on its negative input pin, now voltage comparator 14 exports high level signal to the grid as the N channel field-effect pipe of switch element 11, N channel field-effect pipe is after acquisition high level signal, keep conducting, thus realize the conducting of output circuit 21.
In the present embodiment; power brick protective circuit 10b is lower by cost and the voltage comparator 14 that preparation technology, expansion effect are all very strong prevents the mistake of power brick 20 from putting; without the need to adjusting the output voltage of power brick 20; simplify the structure of power brick protective circuit 10b; while ensure that each element utilization rate, effectively control the design of power brick protective circuit 10b, manufacturing cost.
In other embodiments of the present invention, power brick protective circuit 10b also can comprise the voltage transformation module described in the first embodiment, the output voltage of power brick 20 is obtained by voltage transformation module, and step-down process is done to output voltage, thus output sampling voltage, then sampling voltage is transferred to the positive input pin of voltage comparator; Meanwhile, reference voltage generation module, generates and revises reference voltage, and the ratio of the reference voltage before revising reference voltage and revising equals the ratio of sampling voltage and output voltage.By reducing the voltage be loaded on the positive and negative input pin of voltage comparator 14; the less voltage comparator 14 of detection voltage range is made to can be used for the Cross prevention of the more power brick of battery number 20 equally; improve the versatility of power brick protective circuit 10b for each middle type cell bag 20, thus reduce the design difficulty of power brick protective circuit 10b.
Equally, in the present embodiment, monocell protect IC 13 and the switch element 11 coordinating this chip to use and voltage comparator 14 are common discrete function element; Power brick protective circuit 10b, by aforementioned all discrete function element and monocell protect IC 13 being jointly arranged on one piece of circuit board, making the design technology of power brick protective circuit 10b simpler, is convenient to its large-scale production.Simultaneously; the size of monocell protect IC 13 is less; by each discrete component on arrangement circuit board; effectively can ensure that the volume of power brick protective circuit 10b can not be excessive; make power brick protective circuit 10b can adapt to current application power brick or electric tool widely, improve the practicality of power brick protective circuit 10b.
Compared with prior art, power brick protective circuit 10b provided by the present invention, can complete and the mistake of the power brick with multiple batteries is put and overcurrent protection, in Cross prevention process, by cost is lower and preparation technology, the monocell protect IC 13 that expansion effect is all very strong and voltage comparator 14 judge releasing of power brick 20 and cross to put respectively, while ensureing that power brick is crossed and put judgment accuracy, effectively reduce the manufacturing cost of power brick protective circuit 10b, volume does not have a larger increase simultaneously, ensure that the scope of application of power brick protective circuit 10b, there is very strong market value.
Be to be understood that, although this specification is described according to execution mode, but not each execution mode only comprises an independently technical scheme, this narrating mode of specification is only for clarity sake, those skilled in the art should by specification integrally, technical scheme in each execution mode also through appropriately combined, can form other execution modes that it will be appreciated by those skilled in the art that.
A series of detailed description listed is above only illustrating for feasibility execution mode of the present invention; they are also not used to limit the scope of the invention, all do not depart from the skill of the present invention equivalent implementations done of spirit or change all should be included within protection scope of the present invention.
Claims (12)
1. a power brick protective circuit, for the protection of the power brick with N batteries, N be more than or equal to 2 integer, described power brick has output circuit, it is characterized in that, described power brick protective circuit comprises:
Switch element, is series in described output circuit;
Monocell protect IC, for
Obtain the output parameter of described power brick;
Judge whether described output parameter is positioned at preset parameter range, if not, control described switch element
Disconnect, if so, keep described switching means conductive;
Supply module, for
Obtain the output voltage of power brick;
Power to after doing step-down process to described output voltage described monocell protect IC.
2. power brick protective circuit as claimed in claim 1, it is characterized in that, described output parameter comprises output voltage, and described preset parameter range comprises predetermined voltage range, and described power brick protective circuit also comprises:
Voltage transformation module, for
Obtain the output voltage of described power brick;
Step-down process is done to described output voltage, and exports sampling voltage;
Described monocell protect IC, for
Obtain described sampling voltage;
Judge whether described sampling voltage is positioned at described predetermined voltage range, if not, control described switch
Unit disconnects, and if so, keeps described switching means conductive.
3. power brick protective circuit as claimed in claim 2, it is characterized in that, described sampling voltage is the 1/N of described output voltage.
4. power brick protective circuit as claimed in claim 2, it is characterized in that, described supply module exports starting resistor to after the step-down of power brick output voltage, and described sampling voltage equals described starting resistor.
5. power brick protective circuit as claimed in claim 4, is characterized in that, described power brick protective circuit comprises for bleeder circuit or the step-down chip simultaneously as supply module and voltage transformation module.
6. power brick protective circuit as claimed in claim 5; it is characterized in that; described monocell protect IC comprises the chip that model is S8261-C; described S8261-C chip comprises positive and negative power input terminal; described negative supply input terminal ground connection is arranged, and described positive supply input terminal connects the output of described bleeder circuit or step-down chip.
7. power brick protective circuit as claimed in claim 6; it is characterized in that; described switch element comprises N channel field-effect pipe, and described S8261-C chip comprises control of discharge splicing ear, and described control of discharge splicing ear connects the grid of described N channel field-effect pipe.
8. power brick protective circuit as claimed in claim 1, it is characterized in that, described output parameter comprises output current, and described preset parameter range comprises predetermined current scope, and described power brick protective circuit also comprises:
Current detection module, for detecting the output current of power brick;
Described monocell protect IC also for
Obtain described output current;
Judge whether described output current is positioned at described predetermined current scope, if not, control described switch
Unit disconnects, and if so, keeps described switching means conductive.
9. power brick protective circuit as claimed in claim 8, it is characterized in that, described current detection module comprises:
Sampling resistor, described output current flows through described sampling resistor;
Described monocell protect IC comprises voltage detection terminal, and described sampling resistor one end ground connection is arranged, and the other end is connected to described voltage detection terminal.
10. power brick protective circuit as claimed in claim 9, it is characterized in that, described power brick protective circuit also comprises:
Reference voltage generation module, exports a reference voltage;
Voltage comparator, comprises positive and negative input pin and an output pin, and described negative input pin connects reference voltage generation module, and described positive input pin obtains the output voltage of described power brick, and described output pin is connected to described switch element; When the input voltage of described power brick is greater than described reference voltage, described output pin controls described switch element and disconnects, otherwise described output pin keeps described switching means conductive.
11. 1 kinds of power brick, carry out electric discharge think that it provides electric power for being connected with electric tool, it is characterized in that, described power brick comprises:
Housing;
N batteries, is contained in described housing, N be more than or equal to 2 integer; And
Power brick protective circuit according to any one of aforementioned claim 1 to 10, be contained in described housing, described power brick has output circuit, and described power brick protective circuit connects described output circuit.
12. 1 kinds of electric tools, can be connected with the power brick with multiple batteries, it is characterized in that, described electric tool comprises:
Device body, comprises casing, the motor be accommodated in casing, by described motor-driven working head, for installing the Plug Division of power brick, described Plug Division obtains the electric power of described power brick and is passed to described motor after installation power brick; And
Power brick protective circuit according to any one of aforementioned claim 1 to 10, described power brick protective circuit is arranged in described casing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410016568.2A CN104779586A (en) | 2014-01-15 | 2014-01-15 | Battery pack protection circuit, battery pack and electromotive tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410016568.2A CN104779586A (en) | 2014-01-15 | 2014-01-15 | Battery pack protection circuit, battery pack and electromotive tool |
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| Publication Number | Publication Date |
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| CN104779586A true CN104779586A (en) | 2015-07-15 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410016568.2A Pending CN104779586A (en) | 2014-01-15 | 2014-01-15 | Battery pack protection circuit, battery pack and electromotive tool |
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Application publication date: 20150715 |