A current detection power device, lithium battery protector and electronic equipment

Abstract

The present invention provides a current detection power device for lithium battery protection, the device is electrically connected to a lithium battery protection board, a lithium battery protector and an electronic device, the device is formed by a plurality of power devices with the same structure connected in parallel and integrated; the device includes at least one main power device and at least one current detection device, wherein the main power device and the current detection device share a drain as an input terminal, and a common gate as a control terminal; the main power device and the current detection device each have an independent source as an output terminal. The current detection power device for lithium battery protection provided by the present invention has high density and small area, and can be used in a lithium battery protection circuit to solve the problem that the resistance value of the sampling resistor affects the total resistance value in the loop, thereby causing the standby time of the whole machine to decrease.

Description

Technical Field

[0001] The present invention relates to the field of lithium battery protection, and in particular to a current detection power device, a lithium battery protector and electronic equipment for lithium battery protection. Background Art

[0002] A lithium battery charging protection circuit in the prior art, such as Figure 1 As shown, it includes a lithium battery protection board, a resistor R2, a MOS tube Q1 and a MOS tube Q2. Figure 1 In the embodiment, the discharge control terminal DO of the lithium battery protection board is connected to the gate of the MOS tube Q1, the source of the MOS tube Q1 is connected to the negative electrode of the lithium battery, and the drain of the MOS tube Q1 is connected to the drain of the MOS tube Q2; the charging control terminal CO of the lithium battery protection board is connected to the gate of the MOS tube Q2, the source of the MOS tube Q2 is connected to one end of the resistor R2 and the negative output VCC- of the charging circuit; the other end of the resistor R2 is connected to the first detection terminal VM of the lithium battery protection board.

[0003] In the prior art, the first detection terminal VM of the lithium battery protection board usually detects the charging current through the resistor R2, but R2 must be a high-precision resistor, which is costly, and the current detection accuracy is limited by the accuracy of R2; and the response speed of this circuit structure is not fast. And for a large-capacity battery, the resistance value of the sampling resistor will greatly increase the total resistance value in the entire circuit, thereby increasing the power consumption of the system and greatly reducing the standby time of the whole machine. Summary of the invention

[0004] The invention provides a device for lithium battery protection, which solves the problem in the prior art that the resistance value of the sampling resistor affects the total resistance value in the loop, thereby causing the standby time of the whole device to decrease.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a current detection power device for lithium battery protection, characterized in that the device is integrated by connecting multiple power devices with the same structure in parallel; the current detection power device for lithium battery protection is

[0006] The present invention comprises at least one main power device and at least one current detection device, wherein the main power device and the current detection device share a drain as an input terminal and a gate as a control terminal; the main power device and the current detection device each have an independent source as an output terminal.

[0007] Furthermore, the multiple power devices with the same structure all have a surface electrode pull-down structure.

[0008] Furthermore, the surface electrode pull-down structure is a Body pull-down structure.

[0009] Furthermore, the power device of the Body pull-down structure includes:

[0010] P-type substrate;

[0011] A gate, a source electrode and a drain electrode respectively located on both sides of the gate;

[0012] The Body region is located at the bottom of the P-type substrate;

[0013] The gate, the source and the drain are led out from the surface of the device; and the body region is led out from the bottom of the device.

[0014] Furthermore, the surface electrode pull-down structure is a drain pull-down structure.

[0015] Furthermore, the power device of the drain pull-down structure includes:

[0016] BN area;

[0017] an N-type well region located above the BN region;

[0018] A deep hole region is located in the N-type well region, the deep hole region is connected to the BN region, and a metal lead-out drain is filled in the deep hole region, so that the drain N+ region is conductive with the BN region.

[0019] Furthermore, the multiple power devices with the same structure all have a gate trench structure.

[0020] Furthermore, the gate trench structure power device includes:

[0021] BN area;

[0022] an N-type well region located above the BN region;

[0023] A drain located in the middle of the N-type well region;

[0024] A first gate region and a second gate region are located on both sides of the drain and are arranged opposite to the drain, and both the first gate region and the second gate region are Trench structures.

[0025] Furthermore, the device current flows from the active region N+ of the source, then bypasses the gates of the trench structures on both sides, and is finally collected by the N-type source region N+ of the drain region.

[0026] Furthermore, the source terminal of the current detection device is connected to the current detection VM terminal of the lithium battery protection board; when the main power device is turned on, the VM terminal directly samples the current through the source terminal of the current detection device to detect the current.

[0027] In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a lithium battery protector, wherein the lithium battery protector includes the above-mentioned current detection power device for lithium battery protection.

[0028] In order to solve the above technical problem, another technical solution adopted by the present invention is to provide an electronic device, wherein the electronic device includes the above-mentioned lithium battery protector.

[0029] The beneficial effects of the present invention are as follows: the present invention provides a current detection power device for lithium battery protection. By integrating multiple MOS power devices into one power device, the power device in the present invention is used in a lithium battery protection circuit. High-precision resistors are not used in the circuit, and at the same time, the maximum current accuracy requirements can be met, which not only reduces costs, but also improves current detection accuracy, and also has the advantage of fast response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of a traditional lithium battery charging protection circuit;

[0031] Figure 2 It is a schematic diagram of the lithium battery charging protection circuit in the present invention;

[0032] Figure 3 It is a schematic diagram of the structure of a single device in the current detection power device for lithium battery protection in the present invention;

[0033] Figure 4 It is a structural schematic diagram of a current detection power device for lithium battery protection in the present invention;

[0034] Figure 5 Another structural schematic diagram of a single device in the current detection power device for lithium battery protection in the present invention;

[0035] Figure 6 It is another structural schematic diagram of the current detection power device for lithium battery protection in the present invention;

[0036] Figure 7 Another structural schematic diagram of a single device in the current detection power device for lithium battery protection in the present invention;

[0037] Figure 8 It is another structural schematic diagram of the current detection power device used for lithium battery protection in the present invention. DETAILED DESCRIPTION

[0038] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. Preferred embodiments of the present invention are provided in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0039] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0040] like Figure 2 As shown, the current detection power device for lithium battery protection in this embodiment is electrically connected to the lithium battery protection board, and the power device is formed by parallel integration of multiple power devices with the same structure; in this embodiment, the current detection power device for lithium battery protection is formed by parallel and integrated connection of a main power device FET1 and a current detection device FET2, wherein the drains of the main power device FET1 and the current detection device FET2 are connected, the two share the drain as the input terminal, and the two share the gate as the control terminal, wherein the gate of the main power device FET1 is connected to the DO terminal of the lithium battery protection board, and the gate of the current detection device FET2 is connected to the CO terminal of the lithium battery protection board; the main power device FET1 and the current detection device FET2 each have an independent source as the output terminal, wherein the source S1 of the main power device FET1 is connected to the negative electrode of the battery, and the source CS of the current detection device FET2 is connected to the current detection VM terminal of the lithium battery protection board, and when the main power device FET1 is turned on, the VM terminal directly samples the current through the source CS terminal of the current detection device FET2 for current detection.

[0041] The current detection power device for lithium battery protection in this embodiment is formed by integrating multiple power devices with the same structure in parallel, wherein each power device with the same structure is a surface electrode pull-down structure, including a body pull-down structure and a drain pull-down structure.

[0042] like Figure 3 and Figure 4 As shown, Figure 3 It is a schematic diagram of the structure of a single device in a current detection power device for lithium battery protection; Figure 4 It is a schematic diagram of the structure of a current sensing power device used for lithium battery protection.

[0043] exist Figure 3In the device, a single device includes a P-type substrate, a gate, a source and a drain extending from the device surface, wherein the source and the drain are located on both sides of the gate; the body region is located at the bottom of the P-type substrate, and the body region is extended from the bottom of the device. The body region is extended at the bottom of the device, while the source and the drain are extended on the surface of the device, which improves the reliability of the device on the one hand and reduces the area of ​​the device on the other hand.

[0044] Furthermore, the device in this embodiment includes a first N-type well region 101 and a second N-type well region 102, wherein the first N-type well region is provided with a first N+ contact region 103, and the second N-type well region is provided with a second N+ contact region 104; wherein the drain is led out from the first N+ contact region 103, and the source is led out from the second N+ contact region 104.

[0045] The device further includes a first STI region 105 and a second STI region 106 , wherein the first STI region 105 is located on the other side of the first N-type well region 101 , and the second STI region 106 is located on the other side of the second N-type well region 102 .

[0046] The current flow path in the device is: the current flows into the Drain end of each device, passes through the Body area downward, and then flows upward from the Source end.

[0047] The device in this embodiment changes the Body region from being led out from the surface of the device to being led out from the bottom of the device, and the Body region is flush with the edges of both sides of the P-type substrate of the device, and the source and drain are led out on the surface of the device. This not only improves the reliability of the device, but also reduces the area of ​​the device, thereby providing conditions for the integration of multiple devices.

[0048] See also Figure 4 , multiple devices are assembled on the same chip, and the original package of each device consists of a gate in the middle, and a drain and a source on both sides of the gate; when multiple devices are connected in parallel, if the drains of two devices are adjacent, the drains of the two devices are merged into one drain; and if the sources of two devices are adjacent, the sources of the two devices are merged into one source.

[0049] The device for lithium battery protection in this embodiment reduces the area of ​​the device by integrating multiple devices on the same chip, pulling down the bodies of the multiple devices and connecting them from the bottom of the device; when multiple devices are connected in parallel, the same poles of adjacent devices are merged to further reduce the area of ​​the device, meeting the ever-increasing density requirements.

[0050] like Figure 5 and Figure 6 As shown, Figure 5 It is another structural schematic diagram of a single device in a current sensing power device for lithium battery protection; Figure 6It is another structural schematic diagram of a current sensing power device for lithium battery protection.

[0051] like Figure 5 As shown, a single device includes a BN region, an N-type well region is injected and diffused through a thermal process to form a final N-type well region, and the N-type well region is located above the BN region; the device also includes a Drain region arranged in the N-type well region, a deep hole region is opened in the Drain region, the BN region is connected, and a metal lead is filled in the deep hole region, so that the current flows out of the N+PB and directly flows into the BN end, and then is led out through the Drain hole at the BN end.

[0052] The device in this embodiment includes a first P-type well region 201 and a second P-type well region 202, wherein the first P-type well region 201 and the second P-type well region 201 are respectively located on both sides of the deep hole region. The first P-type well region 201 includes a first N-type source region 203 and a first P+ type contact region 204, wherein the first N-type source region 203 and the first P+ type contact region 204 are arranged side by side; the second P-type well region 202 includes a second N-type source region 205 and a second P+ type contact region 206, wherein the second N-type source region 205 and the second P+ type contact region 206 are arranged side by side.

[0053] The device further includes a first source 207, which is drawn from the first N-type source region 203 and the first P+ type contact region 204; a second source 208, which is drawn from the second N-type source region 205 and the second P+ type contact region 206. A first gate 209, which is located between the first source 207 and the drain; and a second gate 210, which is located between the second source 208 and the drain.

[0054] The device in this embodiment opens a deep hole area in the Drain area of ​​the device and fills the deep hole area with metal leads, so that the current flows out of N+PB and directly flows into the BN end, and then is led out through the Drain hole at the BN end. This reduces the area of ​​the device, but for the BN area of ​​the Drain lead, the current lead-out area is expanded and the on-resistance is reduced.

[0055] See also Figure 6 , multiple devices are integrated on the same chip, adjacent devices merge adjacent sources and share the source, the PB area of ​​the shared source is set with a P+ and an N+ on both sides of the P+, ​​thus leading out their respective sources. Therefore, multiple devices are integrated in parallel on the same chip, and the device area is greatly reduced.

[0056] The device for lithium battery protection in this embodiment combines multiple devices on the same chip and pulls down the drains of the multiple devices so that the current flows out of N+PB and directly flows into the BN terminal, and then is led out through the Drain hole at the BN terminal. This reduces the area of ​​the device, but for the BN area where the Drain is led out, the current lead-out area is expanded and the on-resistance is reduced.

[0057] The current detection power devices for lithium battery protection in this embodiment may also be devices with a gate trench structure. Figure 7 and Figure 8 As shown, Figure 7 It is another structural schematic diagram of a single device in a current sensing power device for lithium battery protection; Figure 8 It is another structural schematic diagram of a current sensing power device for lithium battery protection.

[0058] like Figure 7 As shown, a single device includes a BN region, an N-type well region is injected and diffused through a thermal process to form a final N-type well region, and the N-type well region is located above the BN region; the device also includes a drain region located in the middle of the N-type well region, and the drain region includes an N+ contact region and a drain electrode led from the N+ contact region. On both sides of the drain N+ contact region, a first gate region 30 and a second gate region 40 are respectively arranged, and the first gate region 30 and the second gate region 40 are both Trench structures.

[0059] The device in this embodiment includes a first P-type well region 101 and a second P-type well region 201, wherein the first P-type well region 101 is located on the other side of the first gate region 307, and the second P-type well region 302 is located on the other side of the second gate region 308. In the first P-type well region 301, a first N-type source region 304 and a first P+ contact region 303 are provided, and a first source Source1 is led out from the first N-type source region 304 and the first P+ contact region 303; in the second P-type well region 302, a second N-type source region 306 and a second P+ contact region 305 are provided, and a second source Source2 is led out from the second N-type source region 306 and the second P+ contact region 305.

[0060] The current of the device in this embodiment flows out from the first N-type source region 304 and the second N-type source region 306 of the first P-type well region 301 and the second P-type well region 302 respectively, then bypasses the gates of the trench structures on both sides, and is finally collected by the N-type source region N+ of the drain region.

[0061] The device in this embodiment changes the gate of the device into a Trench structure, so that the overall voltage-resistant area and current area of ​​the device are shifted from the horizontal direction to the vertical direction, thereby greatly reducing the overall area of ​​the device and improving the on-resistance of the device.

[0062] See also Figure 8 , multiple devices are connected in parallel on the same chip, and the original package of each device consists of a middle Drain and two Sources on both sides of the Drain; when multiple devices are placed side by side, each device shares the P+ at the Source end with the adjacent device, and the shared Source end includes a middle P+ and two N+ on both sides; the Source end at the edge includes a P+ and an N+.

[0063] The current of the device in this embodiment flows out from the N-type source region N+ of the P-type well region at the source end on both sides of the drain end, then bypasses the gates of the trench structure on both sides, and is finally collected by the N-type source region N+ of the drain region Drain.

[0064] The device for lithium battery protection in this embodiment combines multiple devices on the same chip and sets the gate regions of the multiple devices into a trench structure, so that the overall voltage-resistant region and current region of the device are shifted from the horizontal direction to the vertical direction, thereby greatly reducing the overall area of ​​the device and improving the on-resistance of the device.

[0065] The current detection power device for lithium battery protection in the embodiment of the present invention greatly reduces the device area by integrating multiple MOS power devices into one power device; in addition, the power device in the present invention is used in a lithium battery protection circuit, and high-precision resistors are not used in the circuit, and at the same time, the maximum current accuracy requirements can be met, which not only reduces the cost, but also improves the current detection accuracy, and also has the advantage of fast response speed.

[0066] The embodiment of the present invention further provides a lithium battery protector. The lithium battery protector in this embodiment includes the current detection power device for lithium battery protection in the above-mentioned embodiment.

[0067] The embodiment of the present invention further provides an electronic device, and the electronic device in this embodiment includes the lithium battery protector in the above embodiment. The electronic device in this embodiment can be any device including the lithium battery protector in the above embodiment.

[0068] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A current detection power device for lithium battery protection, characterized in that: The device is formed by integrating a plurality of power devices of the same structure in parallel; the current detection power device for lithium battery protection includes at least one main power device and at least one current detection device, wherein the main power device and the current detection device share a drain as an input terminal and a gate as a control terminal; the main power device and the current detection device each have an independent source as an output terminal; The multiple power devices with the same structure all have surface electrode pull-down structures; The surface electrode pull-down structure is a Body pull-down structure; The power device of the Body pull-down structure includes: P-type substrate; A gate, a source electrode and a drain electrode respectively located on both sides of the gate; The Body region is located at the bottom of the P-type substrate; The gate, the source and the drain are led out from the surface of the device; and the body region is led out from the bottom of the device.

2. A current detection power device for lithium battery protection, characterized in that: The device is formed by integrating a plurality of power devices of the same structure in parallel; the current detection power device for lithium battery protection includes at least one main power device and at least one current detection device, wherein the main power device and the current detection device share a drain as an input terminal and a gate as a control terminal; the main power device and the current detection device each have an independent source as an output terminal; The multiple power devices with the same structure all have surface electrode pull-down structures; The surface electrode pull-down structure is a drain pull-down structure; The power device of the drain pull-down structure comprises: BN area; an N-type well region located above the BN region; A deep hole region is located in the N-type well region, the deep hole region is connected to the BN region, and a metal lead-out drain is filled in the deep hole region, so that the drain N+ region is conductive with the BN region.

3. A lithium battery protector, characterized in that: The lithium battery protector comprises the current detection power device for lithium battery protection as claimed in claim 1 or 2.

4. An electronic device, characterized in that: The electronic device comprises the lithium battery protector according to claim 3.

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