CN103023005B - Electrostatic protection circuit and battery protection circuit - Google Patents
Electrostatic protection circuit and battery protection circuit Download PDFInfo
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Abstract
本发明提供一种静电保护电路及电池保护电路,其中集成电路的静电保护电路中,所述集成电路具有第一连接端和第二连接端,所述静电保护电路包括连接于第一连接端和第二连接端的静电保护器件,该静电保护器件包括埋层、位于埋层上方的P阱、位于埋层上方并与P阱相邻的N阱、在P阱的上部注入形成的第一注入区和在N阱的上部注入形成的第二注入区,其中第一注入区与第一连接端相连,第二注入区与第二连接端相连。本发明的优点在于,可以防止充电器反接时烧毁电池保护电路内的静电保护器件。
The present invention provides an electrostatic protection circuit and a battery protection circuit, wherein in the electrostatic protection circuit of an integrated circuit, the integrated circuit has a first connection terminal and a second connection terminal, and the electrostatic protection circuit includes a connection terminal connected to the first connection terminal and a second connection terminal. An electrostatic protection device at the second connection end, the electrostatic protection device includes a buried layer, a P well located above the buried layer, an N well located above the buried layer and adjacent to the P well, and a first injection region formed by implanting the upper part of the P well and the second injection region formed by implanting on the upper part of the N well, wherein the first injection region is connected to the first connection end, and the second injection region is connected to the second connection end. The invention has the advantage that it can prevent the electrostatic protection device in the battery protection circuit from being burned when the charger is connected in reverse.
Description
【技术领域】【Technical field】
本发明涉及电路设计领域,特别涉及一种静电保护电路及其电池保护电路。The invention relates to the field of circuit design, in particular to an electrostatic protection circuit and a battery protection circuit thereof.
【背景技术】【Background technique】
图1示出了一种电池保护系统的结构图。如图1所示,所述电池保护系统包括电池电芯Bat、电阻R1、电容C1、电池保护电路110、电阻R2、充电功率开关130和放电功率开关120。电阻R1和电容C1串联于电池电芯Bat的正极B+和负极B-之间,充电功率开关和放电功率开关串联于电池电芯的负极B-和电池的负极P-之间,电池电芯Bat的正极B+直接与电池的正极P+之间。Fig. 1 shows a structural diagram of a battery protection system. As shown in FIG. 1 , the battery protection system includes a battery cell Bat, a resistor R1 , a capacitor C1 , a battery protection circuit 110 , a resistor R2 , a charging power switch 130 and a discharging power switch 120 . The resistor R1 and the capacitor C1 are connected in series between the positive pole B+ and the negative pole B- of the battery cell Bat, the charging power switch and the discharging power switch are connected in series between the negative pole B- of the battery cell and the negative pole P- of the battery, the battery cell Bat Between the positive pole B+ of the battery and the positive pole P+ of the battery.
所述放电功率开关包括NMOS(N-channel Metal Oxide Semiconductor)场效应晶体管MN1和寄生于其体内的二极管D1。所述充电功率开关包括NMOS场效应晶体管MN2和寄生于其体内的二极管D2。NMOS晶体管MN1的漏极和NMOS晶体管MN2的漏极相连,NMOS晶体管MN1的源极与电池电芯的负极B-相连,NMOS晶体管MN2的源极与电池的负极P-相连。The discharge power switch includes an NMOS (N-channel Metal Oxide Semiconductor) field effect transistor MN1 and a diode D1 parasitic in its body. The charging power switch includes an NMOS field effect transistor MN2 and a diode D2 parasitic in its body. The drain of the NMOS transistor MN1 is connected to the drain of the NMOS transistor MN2, the source of the NMOS transistor MN1 is connected to the negative pole B- of the battery cell, and the source of the NMOS transistor MN2 is connected to the negative pole P- of the battery.
所述电池保护电路110包括三个连接端(或称为检测端)和两个控制端,三个连接端分别为电池电芯正极B+连接端(或称电源端)VDD,电池电芯负极B-连接端VSS和电池负极P-连接端VM,两个控制端分别为充电控制端COUT和放电控制端DOUT。其中连接端VDD连接于电阻R1和电容C1之间,连接端VSS与电池电芯的负极B-相连,连接端VM通过电阻R2连接于电池的负极P-,充电控制端COUT与充电功率开关130的控制端相连,即NMOS晶体管MN2的栅极,放电控制端DOUT与放电功率开关120的控制端相连,即NMOS晶体管MN1的栅极。The battery protection circuit 110 includes three connection terminals (or detection terminals) and two control terminals. The three connection terminals are respectively the battery cell positive terminal B+ connection terminal (or power supply terminal) VDD, and the battery cell negative terminal B -connection terminal VSS and battery negative P-connection terminal VM, the two control terminals are charge control terminal COUT and discharge control terminal DOUT respectively. The connection terminal VDD is connected between the resistor R1 and the capacitor C1, the connection terminal VSS is connected to the negative pole B- of the battery cell, the connection terminal VM is connected to the negative pole P- of the battery through the resistor R2, and the charging control terminal C OUT is connected to the charging power switch The control terminal of 130 is connected to the gate of the NMOS transistor MN2, and the discharge control terminal D OUT is connected to the control terminal of the discharge power switch 120, which is the gate of the NMOS transistor MN1.
所述电池保护电路110可以对电池电芯Bat进行充电保护和放电保护。在进行正常充电时,所述电池保护电路110控制NMOS晶体管MN2导通,NMOS晶体管MN1截止,充电电流从NMOS晶体管MN1的体二极管D1流到NMOS晶体管MN2。在充电发生异常(比如充电过流和充电过压)时,所述电池保护电路110控制NMOS晶体管MN2截止,从而切断了充电过程。在进行正常放电时,所述电池保护电路110控制NMOS晶体管MN2截止,NMOS晶体管MN1导通,放电电流从NMOS晶体管MN2的体二极管D2流到NMOS晶体管MN1。在放电发生异常(比如放电过流和放电过压)时,所述电池保护电路110控制NMOS晶体管MN1截止,从而切断了放电过程。The battery protection circuit 110 can perform charge protection and discharge protection for the battery cell Bat. During normal charging, the battery protection circuit 110 controls the NMOS transistor MN2 to be turned on and the NMOS transistor MN1 to be turned off, so that the charging current flows from the body diode D1 of the NMOS transistor MN1 to the NMOS transistor MN2. When abnormal charging occurs (such as charging overcurrent and charging overvoltage), the battery protection circuit 110 controls the NMOS transistor MN2 to be turned off, thereby cutting off the charging process. During normal discharge, the battery protection circuit 110 controls the NMOS transistor MN2 to be turned off, the NMOS transistor MN1 to be turned on, and the discharge current flows from the body diode D2 of the NMOS transistor MN2 to the NMOS transistor MN1 . When abnormal discharge occurs (such as discharge overcurrent and discharge overvoltage), the battery protection circuit 110 controls the NMOS transistor MN1 to be turned off, thereby cutting off the discharge process.
静电防护对集成电路来说非常重要,在工业界已经进行了许多研究。无论是在电子设备的正常使用,运榆和库存,以及在生产装配各种集成电路元件都有可能发生静电放电。这些难以正确预见和防范的静电放电会损坏集成电路,产生不良率,甚至导致巨额损失。在目前的集成电路设计和制造时都会特别注意静电放电保护电路的设计。静电放电保护电路通常是连接在两个不同的管脚之间,与内部电路并联。随着静电放电保护电路两端的静电电荷不断积累,这两端的电压将不断增加,一旦达到静电放电保护电路的激活放电阈值,静电放电保护电路就开始泻放静电,从而实现保护内部电路的功能。这里所述的激活放电阈值对于大多数现有技术来说为击穿电压(breakdown voltage)。ESD protection is very important for integrated circuits, and a lot of research has been done in the industry. No matter in the normal use of electronic equipment, transportation and inventory, and in the production and assembly of various integrated circuit components, electrostatic discharge may occur. These electrostatic discharges, which are difficult to predict and prevent correctly, can damage integrated circuits, generate defective rates, and even lead to huge losses. In the design and manufacture of current integrated circuits, special attention will be paid to the design of electrostatic discharge protection circuits. The ESD protection circuit is usually connected between two different pins in parallel with the internal circuit. As the electrostatic charges at both ends of the ESD protection circuit continue to accumulate, the voltage at both ends will continue to increase. Once the activation discharge threshold of the ESD protection circuit is reached, the ESD protection circuit will start to discharge static electricity, thereby realizing the function of protecting the internal circuit. The activation discharge threshold mentioned here is the breakdown voltage for most existing technologies.
通常,图1中的电池保护电路110是一块芯片,其各个连接端之间也需要设置静电保护电路(ESD)。特别的,在电源端VDD和电池负极连接端VM之间也设置有如图2所示的静电保护器件。如图2所示,所述静电保护器件包括N型埋层DN、位于N型埋层DN上方的P阱PWELL、位于N型埋层上方并将P阱PELL夹在中间的两个N阱NWELL、在P阱PWELL的上部注入形成的N型注入区N_implant和P型注入区P_implant、在N阱的上部注入形成的N型注入区N_implant。N_implant为深度较浅但浓度更高的N型注入,P_implant为深度较浅但浓度更高的P型注入。Generally, the battery protection circuit 110 in FIG. 1 is a chip, and an electrostatic protection circuit (ESD) needs to be provided between each connection terminal of the chip. In particular, an electrostatic protection device as shown in FIG. 2 is also provided between the power supply terminal VDD and the battery negative connection terminal VM. As shown in Figure 2, the electrostatic protection device includes an N-type buried layer DN, a P well PWELL located above the N-type buried layer DN, two N wells NWELL located above the N-type buried layer and sandwiching the P well PELL , the N-type implantation region N_implant and the P-type implantation region P_implant formed in the upper part of the P well PWELL, and the N-type implantation region N_implant formed in the upper part of the N well. N_implant is an N-type implant with a shallower depth but a higher concentration, and P_implant is a P-type implant with a shallower depth but a higher concentration.
如图2所示,P阱上部的N型注入区和P型注入区都与连接端VM相连,N阱上部的N型注入区与电源端VDD相连,图2中的静电保护器件是一个三极管,其中NWELL形成集电极,P型注入区P_implant和P阱PWELL形成基极,N型注入区N_implant形成射极。在VDD和VM之间出现静电时,这个三极管被击穿从而提供静电释放的大电流通路。As shown in Figure 2, both the N-type injection region and the P-type injection region on the upper part of the P well are connected to the connection terminal VM, and the N-type injection region on the upper part of the N well is connected to the power supply terminal VDD. The electrostatic protection device in Figure 2 is a triode , wherein NWELL forms the collector, the P-type implant region P_implant and the P well PWELL form the base, and the N-type implant region N_implant forms the emitter. When static electricity occurs between VDD and VM, this transistor is broken down to provide a large current path for electrostatic discharge.
然而,如图3所示,此静电保护器件会形成一个寄生二极管ESD-Diode,其由P阱PWELL和N阱NWELL的PN结构成。由于该二极管属于静电释放放电通路,所以不能在电池保护电路内增加限流电阻限制流过这个寄生二极管的电流,如果电池应用中充电器极性接反,电池负极P-端会被充电器拉高到高于P+端,当VM电压高于VDD时,会有很大电流流过该寄生二极管,导致电池保护电路芯片烧毁,为防止出现电池保护电路芯片烧坏或工作异常。电池保护业界普遍通过外接限流电阻R2来限制P-电位高于P+电位时从VM端流入电池保护电路芯片的电流。However, as shown in FIG. 3, this electrostatic protection device will form a parasitic diode ESD-Diode, which is composed of a PN structure of P well PWELL and N well NWELL. Since the diode belongs to the electrostatic discharge discharge path, it is not possible to add a current-limiting resistor in the battery protection circuit to limit the current flowing through this parasitic diode. If the polarity of the charger is reversed in the battery application, the negative P- terminal of the battery will be pulled by the charger. Higher than the P+ terminal, when the VM voltage is higher than VDD, a large current will flow through the parasitic diode, causing the battery protection circuit chip to burn out, in order to prevent the battery protection circuit chip from burning out or working abnormally. In the battery protection industry, an external current-limiting resistor R2 is generally used to limit the current flowing from the VM terminal into the battery protection circuit chip when the P- potential is higher than the P+ potential.
这样,就在应用电路中额外增加了一个分立器件电阻,增加了系统成本。因此有必要提供一种改进的技术方案来克服上述问题。In this way, an additional discrete device resistor is added to the application circuit, increasing system cost. Therefore, it is necessary to provide an improved technical solution to overcome the above problems.
【发明内容】【Content of invention】
本发明的目的在于提供一种静电保护电路及应用该静电保护电路的电池保护电路芯片,可以防止充电器反接时烧毁电池保护电路内的静电保护器件。The purpose of the present invention is to provide an electrostatic protection circuit and a battery protection circuit chip using the electrostatic protection circuit, which can prevent the electrostatic protection device in the battery protection circuit from being burned when the charger is connected in reverse.
为了解决上述问题,根据本发明的一方面,本发明提供一种集成电路的静电保护电路,所述集成电路具有第一连接端和第二连接端,所述静电保护电路包括连接于第一连接端和第二连接端的静电保护器件,该静电保护器件包括埋层、位于埋层上方的P阱、位于埋层上方并与P阱相邻的N阱、在P阱的上部注入形成的第一注入区和在N阱的上部注入形成的第二注入区,其中第一注入区与第一连接端相连,第二注入区与第二连接端相连。In order to solve the above problems, according to one aspect of the present invention, the present invention provides an electrostatic protection circuit for an integrated circuit, the integrated circuit has a first connection end and a second connection end, and the electrostatic protection circuit includes a terminal and the second connection terminal, the electrostatic protection device includes a buried layer, a P well located above the buried layer, an N well located above the buried layer and adjacent to the P well, and a first injection formed on the upper part of the P well. An injection region and a second injection region implanted on the upper part of the N well, wherein the first injection region is connected to the first connection end, and the second injection region is connected to the second connection end.
进一步的,埋层为N型,第一注入区和第二注入区均为N型,所述N阱为两个,两个N阱将P阱夹在中间,每个N阱的上部都形成有第二注入区,N型注入区的N型掺杂浓度较N阱的N型掺杂浓度高。Further, the buried layer is N-type, the first injection region and the second injection region are both N-type, and there are two N wells, the two N wells sandwich the P well, and the upper part of each N well is formed There is a second implantation region, and the N-type doping concentration of the N-type implantation region is higher than the N-type doping concentration of the N well.
进一步的,在第一连接端和第二连接端之间有静电时,所述静电保护器件提供第一连接端和第二连接端之间的静电泄放路径,该静电保护器件形成第一寄生二极管和第二寄生二极管,其中第一寄生二极管的阴极与第二连接端相连,第一寄生二极管的阳极与第二寄生二极管的阳极相连,第二寄生二极管的阴极与第一连接端相连。Further, when there is static electricity between the first connection end and the second connection end, the electrostatic protection device provides an electrostatic discharge path between the first connection end and the second connection end, and the electrostatic protection device forms a first parasitic A diode and a second parasitic diode, wherein the cathode of the first parasitic diode is connected to the second connection terminal, the anode of the first parasitic diode is connected to the anode of the second parasitic diode, and the cathode of the second parasitic diode is connected to the first connection terminal.
进一步的,埋层为P型,第一注入区和第二注入区均为P型,所述P阱为两个,两个P阱将N阱夹在中间,每个P阱的上部都形成有第一注入区,P型注入区的P型掺杂浓度较P阱的P型掺杂浓度高。Further, the buried layer is P-type, the first injection region and the second injection region are both P-type, there are two P wells, and the N well is sandwiched between the two P wells, and the upper part of each P well is formed There is a first implantation region, and the P-type doping concentration of the P-type implantation region is higher than the P-type doping concentration of the P well.
进一步的,在第一连接端和第二连接端之间有静电时,所述静电保护器件提供第一连接端和第二连接端之间的静电泄放路径,该静电保护器件形成第一寄生二极管和第二寄生二极管,其中第一寄生二极管的阳极与第一连接端相连,第一寄生二极管的阴极与第二寄生二极管的阴极相连,第二寄生二极管的阳极与第二连接端相连。Further, when there is static electricity between the first connection end and the second connection end, the electrostatic protection device provides an electrostatic discharge path between the first connection end and the second connection end, and the electrostatic protection device forms a first parasitic A diode and a second parasitic diode, wherein the anode of the first parasitic diode is connected to the first connection terminal, the cathode of the first parasitic diode is connected to the cathode of the second parasitic diode, and the anode of the second parasitic diode is connected to the second connection terminal.
根据本发明的另一方面,本发明提供一种电池保护电路,其包括与电池负极连接的电池负极连接端VM、与电池电芯负极连接的电池电芯负极连接端VSS、电源端VDD、与放电功率开关的控制端连接的放电控制端和与充电功率开关的控制端连接的充电控制端,其还包括连接于电池负极连接端VM和电源端VDD之间的如权利要求1-5任一所述的静电保护器件,其中所述电池负极连接端VM为第一连接端,所述电源端VDD为第二连接端。According to another aspect of the present invention, the present invention provides a battery protection circuit, which includes a battery negative connection terminal VM connected to the battery negative pole, a battery cell negative connection terminal VSS connected to the battery cell negative pole, a power supply terminal VDD, and The discharge control terminal connected to the control terminal of the discharge power switch and the charge control terminal connected to the control terminal of the charge power switch, which also includes any one of claims 1-5 connected between the battery negative connection terminal VM and the power supply terminal VDD. Said electrostatic protection device, wherein said battery negative connection terminal VM is a first connection terminal, and said power supply terminal VDD is a second connection terminal.
进一步的,所述电池保护电路还包括控制电路和串联在电池负极连接端VM和电池电芯负极连接端VSS之间的放电通路,该放电通路上包括开关器件、二极管和电阻R0,在进入放电过流保护状态后,所述控制电路控制所述开关器件导通以使电池负极连接端和电池电芯负极连接端之间的放电通路导通,所述控制电路根据电池负极连接端的电压确定是否退出放电过流保护状态,在确定退出放电过流保护状态后,所述控制电路控制所述开关器件截止以使得电池负极连接端和电池电芯负极连接端之间的放电通路截止。Further, the battery protection circuit also includes a control circuit and a discharge path connected in series between the battery negative connection terminal VM and the battery cell negative connection terminal VSS. The discharge path includes a switching device, a diode and a resistor R0. After the overcurrent protection state, the control circuit controls the switching device to conduct to conduct the discharge path between the battery negative terminal and the battery cell negative terminal, and the control circuit determines whether to Exit the discharge overcurrent protection state. After determining to exit the discharge overcurrent protection state, the control circuit controls the switching device to cut off so that the discharge path between the battery negative connection end and the battery cell negative connection end is cut off.
进一步的,所述二极管的阴极连接所述开关器件的一个连接端,所述二极管的阳极与所述电池负极连接端相连,所述开关器件的另一个连接端与所述电池电芯负极连接端相连,所述放电通路提供毫安级别及以下的电流。Further, the cathode of the diode is connected to one connection end of the switching device, the anode of the diode is connected to the negative connection end of the battery, and the other connection end of the switch device is connected to the negative connection end of the battery cell. connected, the discharge path provides a current of milliampere level and below.
进一步的,在放电过流保护状态下,在所述电池负极连接端的电压低于预定电压阈值时,所述控制电路确定退出放电过流保护状态,所述控制电路根据电池负极连接端和电池电芯负极连接端之间的压差确定是否进入放电过流保护状态。Further, in the discharge overcurrent protection state, when the voltage at the negative terminal of the battery is lower than a predetermined voltage threshold, the control circuit determines to exit the discharge overcurrent protection state, and the control circuit determines to exit the discharge overcurrent protection state according to the negative connection terminal of the battery and the battery voltage. The voltage difference between the negative terminals of the core determines whether to enter the discharge overcurrent protection state.
更进一步的,所述开关器件为NMOS场效应晶体管,所述控制电路输出控制信号至所述NMOS场效应晶体管的栅极。Furthermore, the switching device is an NMOS field effect transistor, and the control circuit outputs a control signal to the gate of the NMOS field effect transistor.
与现有技术相比,本发明中的静电保护器件形成有两个正偏方向相反的串联二极管,这两个二极管分别保证正常工作电压,以及反接充电器时电池保护电路芯片的耐压和防漏电的能力,这样可以省去电池保护电路芯片应用电路中外接给连接端VM的电阻。Compared with the prior art, the electrostatic protection device in the present invention has two series diodes with opposite forward bias directions, and these two diodes respectively guarantee the normal working voltage, and the withstand voltage and voltage resistance of the battery protection circuit chip when the charger is reversed. The ability to prevent leakage, so that the resistor externally connected to the connection terminal VM in the application circuit of the battery protection circuit chip can be omitted.
【附图说明】【Description of drawings】
为了更清楚地说明本发明实施例的技术方案,下面将对实施例描述中所需要使用的附图作简单地介绍,显而易见地,下面描述中的附图仅仅是本发明的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动性的前提下,还可以根据这些附图获得其它的附图。其中:In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without any creative effort. in:
图1为电池保护电路系统的结构示意图;FIG. 1 is a schematic structural diagram of a battery protection circuit system;
图2为现有的静电保护器件的结构示意图;Fig. 2 is the structural representation of existing electrostatic protection device;
图3为图2中的静电保护器件的寄生二极管的结构示意图;Fig. 3 is a schematic structural diagram of a parasitic diode of the electrostatic protection device in Fig. 2;
图4为本发明的一个实施例中的静电保护器件的结构示意图;Fig. 4 is a structural schematic diagram of an electrostatic protection device in an embodiment of the present invention;
图5为图4中的静电保护器件的寄生二极管的结构示意图;FIG. 5 is a schematic structural diagram of a parasitic diode of the electrostatic protection device in FIG. 4;
图6为本发明的另一个实施例中的静电保护器件的结构示意图;6 is a schematic structural view of an electrostatic protection device in another embodiment of the present invention;
图7为图6中的静电保护器件的寄生二极管的结构示意图;FIG. 7 is a schematic structural diagram of a parasitic diode of the electrostatic protection device in FIG. 6;
图8是图1中的电池保护电路中的放电过流自恢复电路的结构示例图。FIG. 8 is a structural example diagram of a discharge overcurrent self-recovery circuit in the battery protection circuit in FIG. 1 .
【具体实施方式】【Detailed ways】
为使本发明的上述目的、特征和优点能够更加明显易懂,下面结合附图和具体实施方式对本发明作进一步详细的说明。In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.
此处所称的“一个实施例”或“实施例”是指可包含于本发明至少一个实现方式中的特定特征、结构或特性。在本说明书中不同地方出现的“在一个实施例中”并非均指同一个实施例,也不是单独的或选择性的与其他实施例互相排斥的实施例。除非特别说明,本文中的连接、相连、相接的表示电性连接的词均表示直接或间接电性相连。Reference herein to "one embodiment" or "an embodiment" refers to a particular feature, structure or characteristic that can be included in at least one implementation of the present invention. "In one embodiment" appearing in different places in this specification does not all refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments. Unless otherwise specified, the words connected, connected, and joined in this document mean that they are electrically connected directly or indirectly.
图4为本发明的一个实施例中的静电保护器件的结构示意图。如图所示,该静电保护器件包括N型埋层DN、位于N型埋层DN上方的P阱PWELL、位于N型埋层上方并夹持P阱PWELL的两个N阱NWELL、在P阱PWELL的上部注入形成的N型注入区N_implant(或称第一注入区)和在N阱NWELL的上部注入形成的N型注入区N_implant(或称第二注入区),其中N阱中的N型注入区与图1中的电池保护电路芯片的电源端VDD相连,P阱中的N型注入区与图1中的电池保护电路芯片的连接端VM相连。N_implant为深度较浅但浓度更高的N型注入。Fig. 4 is a schematic structural diagram of an electrostatic protection device in an embodiment of the present invention. As shown in the figure, the electrostatic protection device includes an N-type buried layer DN, a P-well PWELL located above the N-type buried layer DN, two N-wells NWELL located above the N-type buried layer and sandwiching the P-well PWELL, and the P-well The N-type implant region N_implant (or called the first implant region) formed by the upper part of the PWELL and the N-type implant region N_implant (or called the second implant region) formed by the upper part of the N well NWELL, wherein the N-type implant in the N well The injection region is connected to the power terminal VDD of the battery protection circuit chip in FIG. 1 , and the N-type injection region in the P well is connected to the connection terminal VM of the battery protection circuit chip in FIG. 1 . N_implant is an N-type implant with a shallower depth but a higher concentration.
可以看到,相对于图2的静电保护器件的方案,图4去掉了P阱PWELL中的P型注入区P_implant,这样的做法在保留静电保护器件需要的NPN三极管结构的同时,使电源端VDD到连接端VM之间形成了两个二极管背靠背串联的结构。结合图4和5所示,P阱PWELL到N阱NWELL形成了图5中的第一寄生二极管ESD_diode1,PWELL中的N型注入区N_implant到P阱PWELL形成了图5中的第二个寄生二极管ESD_diode2。It can be seen that, compared with the scheme of the electrostatic protection device in Figure 2, the P-type implant region P_implant in the P well PWELL is removed in Figure 4. This approach keeps the NPN transistor structure required by the electrostatic protection device while making the power supply terminal VDD A back-to-back series connection structure of two diodes is formed to the connection terminal VM. As shown in Figures 4 and 5, the P well PWELL to the N well NWELL form the first parasitic diode ESD_diode1 in Figure 5, and the N-type implant region N_implant in PWELL to the P well PWELL forms the second parasitic diode in Figure 5 ESD_diode2.
结合参考图1和5所示,在电源端VDD到连接端VM的静电释放通路上,设计如图4所示的ESD器件结构,这样既可以保证在电源端VDD到连接端VM之间形成静电释放通路,又能使其形成两个正偏方向相反的串联二极管,其中第一寄生二极管ESD_diode1的阴极与电源端VDD相连,第一寄生二极管ESD_diode1的阳极与第二寄生二极管ESD_diode2的阳极相连,第二寄生二极管ESD_diode2的阴极与连接端VM相连,两个二极管分别保证正常工作电压,以及反接充电器时芯片的耐压和防漏点的能力,这样可以省去如图1中的电池保护电路芯片的应用电路中外接给连接端VM的电阻R2。With reference to Figures 1 and 5, design the ESD device structure shown in Figure 4 on the electrostatic discharge path from the power supply terminal VDD to the connection terminal VM, so as to ensure the formation of static electricity between the power supply terminal VDD and the connection terminal VM. The release path can form two series diodes with opposite forward bias directions, wherein the cathode of the first parasitic diode ESD_diode1 is connected to the power supply terminal VDD, the anode of the first parasitic diode ESD_diode1 is connected to the anode of the second parasitic diode ESD_diode2, and the anode of the second parasitic diode ESD_diode2 is connected. The cathode of the second parasitic diode ESD_diode2 is connected to the connection terminal VM, and the two diodes respectively guarantee the normal working voltage, as well as the ability of the chip to withstand voltage and prevent leakage when the charger is reversed, so that the battery protection circuit shown in Figure 1 can be omitted In the application circuit of the chip, the resistance R2 connected to the connection terminal VM is external.
图6为本发明的另一个实施例中的静电保护器件的结构示意图。如图所示,该静电保护器件包括P型埋层DP、位于P型埋层DP上方的N阱NWELL、位于P型埋层上方并夹持N阱NWELL的两个P阱PWELL、在P阱PWELL的上部注入形成的P型注入区P_implant(或称第一注入区)和在N阱NWELL的上部注入形成的P型注入区P_implant(或称第二注入区),其中P阱中的P型注入区与图1中的电池保护电路芯片的连接端VM相连,N阱中的P型注入区与图1中的电池保护电路芯片的电源端VDD相连。P_implant为深度较浅但浓度更高的P型注入。FIG. 6 is a schematic structural diagram of an electrostatic protection device in another embodiment of the present invention. As shown in the figure, the electrostatic protection device includes a P-type buried layer DP, an N-well NWELL located above the P-type buried layer DP, two P-wells PWELL located above the P-type buried layer and sandwiching the N-well NWELL, and the P-well The P-type implantation region P_implant (or the first implantation region) formed by the upper part of the PWELL and the P-type implantation region P_implant (or the second implantation region) formed by the upper part of the N well NWELL, wherein the P-type implantation region in the P well The injection region is connected to the connection terminal VM of the battery protection circuit chip in FIG. 1 , and the P-type injection region in the N well is connected to the power supply terminal VDD of the battery protection circuit chip in FIG. 1 . P_implant is a P-type implant with a shallower depth but a higher concentration.
结合图6和7所示,N阱NWELL到P阱PWELL形成了图7中的第一寄生二极管ESD_diode1,NWELL中的P型注入区P_implant到N阱NWELL形成了图7中的第二个寄生二极管ESD_diode2。As shown in Figures 6 and 7, the N well NWELL to the P well PWELL forms the first parasitic diode ESD_diode1 in Figure 7, and the P-type implant region P_implant in the NWELL to the N well NWELL forms the second parasitic diode in Figure 7 ESD_diode2.
结合参考图1和7所示,在电源端VDD到连接端VM的静电释放通路上,设计如图6所示的ESD器件结构,这样既可以保证在电源端VDD到连接端VM之间形成静电释放通路,又能使其形成两个正偏方向相反的串联二极管,其中第一寄生二极管ESD_diode1的阳极与连接端VM相连,第一寄生二极管ESD_diode1的阴极与第二寄生二极管ESD_diode2的阴极相连,第二寄生二极管ESD_diode2的阳极与电源端VDD相连,两个二极管分别保证正常工作电压,以及反接充电器时芯片的耐压和防漏点的能力,这样可以省去如图1中的电池保护电路芯片的应用电路中外接给连接端VM的电阻R2。With reference to Figures 1 and 7, design the ESD device structure shown in Figure 6 on the electrostatic discharge path from the power supply terminal VDD to the connection terminal VM, so as to ensure the formation of static electricity between the power supply terminal VDD and the connection terminal VM. The release path can form two series diodes with opposite forward bias directions, wherein the anode of the first parasitic diode ESD_diode1 is connected to the connection terminal VM, the cathode of the first parasitic diode ESD_diode1 is connected to the cathode of the second parasitic diode ESD_diode2, and the second parasitic diode ESD_diode2 is connected to the cathode. The anode of the second parasitic diode ESD_diode2 is connected to the power supply terminal VDD, and the two diodes respectively guarantee the normal working voltage, and the ability of the chip to withstand voltage and prevent leakage when the charger is reversed, so that the battery protection circuit shown in Figure 1 can be omitted In the application circuit of the chip, the resistance R2 connected to the connection terminal VM is external.
所属领域内的普通技术人员能够理解的是,图4和图6中的静电保护器件还可以用于其他集成电路或芯片中进行静电保护,其可以连接在芯片的任意两个管脚或连接端之间。Those of ordinary skill in the art can understand that the electrostatic protection device in Figure 4 and Figure 6 can also be used in other integrated circuits or chips for electrostatic protection, which can be connected to any two pins or connection ends of the chip between.
除了静电保护器件的改变,本发明中的电池保护电路还有另外的改进,下文将详细描述。In addition to the change of the electrostatic protection device, the battery protection circuit in the present invention has another improvement, which will be described in detail below.
请参考图1所示,其中的各个部分的连接关系等在背景中已经都描述过了,这里不再重复描述。在放电时,电池保护电路110通过连接端VM(即电池的负极P-)和VSS(即电池电芯的负极B-)之间的压差来判断是否放电过流。此时VM端的电压高于VSS端的电压,并且两者之间的压差与放电电流成一定比例关系。如果差压超过预定电压阈值,则认为放电电流超过预定电流阈值,则启动放电过流保护功能,将放电控制端DOUT下拉至电池电芯的负极B-电位,禁止所述放电功率开关120进行放电。在放电过流的原因消除时,希望所述电池保护电路110能够自动的检测到,并自动从放电过流状态中恢复出来。Please refer to FIG. 1 , the connection relationship of each part thereof has been described in the background, and will not be repeated here. When discharging, the battery protection circuit 110 judges whether the discharge overcurrent is based on the voltage difference between the connection terminal VM (ie, the negative terminal P- of the battery) and VSS (ie, the negative terminal B- of the battery cell). At this time, the voltage at the VM terminal is higher than the voltage at the VSS terminal, and the voltage difference between the two is proportional to the discharge current. If the differential pressure exceeds the predetermined voltage threshold, it is considered that the discharge current exceeds the predetermined current threshold, and the discharge overcurrent protection function is activated, the discharge control terminal D OUT is pulled down to the negative B-potential of the battery cell, and the discharge power switch 120 is prohibited from performing discharge. When the cause of the discharge overcurrent is eliminated, it is hoped that the battery protection circuit 110 can automatically detect and automatically recover from the discharge overcurrent state.
在本发明中,如图8所示,所述电池保护电路110中包括控制电路和设置于连接端VM和连接端VSS之间的放电通路,所述放电通路包括依次连接于连接端VM和连接端VSS之间的电阻R0、二极管D0和开关器件MN0。所述控制电路根据连接端VM(即电池的负极P-)和VSS(即电池电芯的负极B-)之间的压差来判断是否放电过流,在检测到放电过流时,禁止放电功率开关120放电,这样就进入了放电过流保护状态,与此同时,其还控制所述开关器件MN0导通,这样使得连接端VM和连接端VSS之间的放电通路导通。In the present invention, as shown in FIG. 8 , the battery protection circuit 110 includes a control circuit and a discharge path arranged between the connection terminal VM and the connection terminal VSS. Resistor R0, diode D0 and switching device MN0 between terminals VSS. The control circuit judges whether the discharge overcurrent is based on the voltage difference between the connection terminal VM (ie, the negative pole P- of the battery) and VSS (ie, the negative pole B- of the battery cell), and prohibits the discharge when the discharge overcurrent is detected. The power switch 120 discharges, so that it enters the discharge overcurrent protection state. At the same time, it also controls the switching device MN0 to conduct, so that the discharge path between the connection terminal VM and the connection terminal VSS is conducted.
在放电过流保护时,电池的正负极P+/P-之间的负载会把负极P-电压拉高到接近正极P+的电位,这样VM端的电压会高于VSS端的电压。而在本发明中,设置了一条在放电过流状态下导通的位于连接端VM和VSS之间的通路,这样在放电保护状态下,连接端VSS向连接端VM提供一个下拉电流,一旦放电过流的原因消除,比如短路消除,连接端VM的电压就会被拉低。因此,在本发明中所述控制电路根据连接端VM的电压来确定是否退出放电过流保护状态。在放电过流状态下如果连接端VM的电压低于预定电压阈值时,所述控制电路则决定退出放电过流保护状态,控制所述放电功率开关120恢复正常放电,否则继续保持放电过流保护状态。在所述控制电路210确定退出放电过流保护状态后,控制所述开关器件MN0截止,这样使得连接端VM和连接端VSS之间的放电通路截止,并防止漏电。During discharge overcurrent protection, the load between the positive and negative poles P+/P- of the battery will pull up the negative pole P- voltage to a potential close to the positive pole P+, so that the voltage at the VM terminal will be higher than the voltage at the VSS terminal. However, in the present invention, a path between the connection terminal VM and VSS that is turned on in the discharge overcurrent state is provided, so that in the discharge protection state, the connection terminal VSS provides a pull-down current to the connection terminal VM. When the cause of the overcurrent is eliminated, such as the short circuit is eliminated, the voltage at the connection terminal VM will be pulled down. Therefore, in the present invention, the control circuit determines whether to exit the discharge overcurrent protection state according to the voltage of the connection terminal VM. In the discharge overcurrent state, if the voltage of the connection terminal VM is lower than the predetermined voltage threshold, the control circuit decides to exit the discharge overcurrent protection state, and controls the discharge power switch 120 to resume normal discharge; otherwise, continue to maintain the discharge overcurrent protection state. After the control circuit 210 determines to exit the discharge overcurrent protection state, it controls the switch device MN0 to be turned off, so that the discharge path between the connection terminal VM and the connection terminal VSS is closed, and leakage current is prevented.
为了降低功耗,在放电过流保护状态下,从连接端VM流向连接端VSS的下拉电流很小,为毫安及以下级别的电流,在本发明中可以通过设置电阻R0的大小来调节所述下拉电流的大小。In order to reduce power consumption, in the discharge overcurrent protection state, the pull-down current flowing from the connection terminal VM to the connection terminal VSS is very small, which is a current of milliamps or below. In the present invention, the resistance R0 can be adjusted by setting the size of the resistor R0. The magnitude of the pull-down current mentioned above.
所述二极管D0的阴极连接所述开关器件MN0的一个连接端,所述阳极与连接端VM相连,所述开关器件MN0的另一个连接端与连接端VSS相连。The cathode of the diode D0 is connected to a connection terminal of the switching device MN0 , the anode is connected to the connection terminal VM, and the other connection terminal of the switching device MN0 is connected to the connection terminal VSS.
在一个实施例中,如图2所示,所述开关器件MN0为NMOS场效应晶体管,其栅极接所述控制电路,所述控制电路输出控制信号S1来控制所述开关器件MN0的导通和截止。进入放电过流保护状态时,控制开关器件MN0导通,在退出放电过流状态时,控制开关器件MN0截止。二极管D0用来允许连接端VM向连接端VSS单向通过电流,阻止VSS向VM漏电,并且利用二极管D0的反向耐压能力在VM电压低于VSS时承受VM到VSS的绝大部分压降。电阻R0也可以放置于MN0和二极管D0之间,还可以放置于MN0和VSS之间。In one embodiment, as shown in FIG. 2, the switching device MN0 is an NMOS field effect transistor, the gate of which is connected to the control circuit, and the control circuit outputs a control signal S1 to control the conduction of the switching device MN0 and deadline. When entering the discharge overcurrent protection state, the control switch device MN0 is turned on, and when exiting the discharge overcurrent state, the control switch device MN0 is turned off. Diode D0 is used to allow the connection terminal VM to pass current to the connection terminal VSS in one direction, prevent VSS from leaking to VM, and use the reverse withstand voltage capability of diode D0 to withstand most of the voltage drop from VM to VSS when the voltage of VM is lower than VSS . Resistor R0 can also be placed between MN0 and diode D0, and can also be placed between MN0 and VSS.
在本发明中,“连接”、“相连”、“连”、“接”等表示电性连接的词语,如无特别说明,则表示直接或间接的电性连接。In the present invention, words such as "connected", "connected", "connected" and "connected" that indicate electrical connection, unless otherwise specified, indicate direct or indirect electrical connection.
需要指出的是,熟悉该领域的技术人员对本发明的具体实施方式所做的任何改动均不脱离本发明的权利要求书的范围。相应地,本发明的权利要求的范围也并不仅仅局限于前述具体实施方式。It should be pointed out that any changes made by those skilled in the art to the specific embodiments of the present invention will not depart from the scope of the claims of the present invention. Accordingly, the scope of the claims of the present invention is not limited only to the foregoing specific embodiments.
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US20120250198A1 (en) * | 2011-03-29 | 2012-10-04 | Minoru Sudo | Esd protection circuit for a semiconductor integrated circuit |
CN203205856U (en) * | 2012-11-30 | 2013-09-18 | 无锡中星微电子有限公司 | Electrostatic protection circuit and battery protection circuit thereof |
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CN103023005A (en) | 2013-04-03 |
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Address after: 214028 10th Floor, Area A, 530 Building, Qingyuan Road, Taihu International Science Park, Wuxi New District, Jiangsu Province Patentee after: WUXI ZHONGGAN MICROELECTRONIC CO., LTD. Address before: 214028 10th Floor, Area A, 530 Building, Qingyuan Road, Taihu International Science Park, Wuxi New District, Jiangsu Province Patentee before: Wuxi Vimicro Co., Ltd. |