CN211880118U

CN211880118U - Battery management chip, battery management system and electronic equipment

Info

Publication number: CN211880118U
Application number: CN202020347884.9U
Authority: CN
Inventors: 周号
Original assignee: Zhuhai Maiju Microelectronics Co Ltd
Current assignee: Zhuhai Maiju Microelectronics Co Ltd
Priority date: 2020-03-18
Filing date: 2020-03-18
Publication date: 2020-11-06
Anticipated expiration: 2030-03-18

Abstract

The present disclosure provides a battery management chip, including: the voltage conversion part comprises a voltage reduction type DC-DC switch converter, the input end of the voltage conversion part is connected with the output voltage of the battery, and the voltage reduction type DC-DC switch converter converts the output voltage of the battery into the output voltage of the voltage conversion part and outputs the output voltage through the output end of the voltage conversion part; and the battery management part detects and/or controls the battery, and the power supply end of the battery management part is connected with the output end of the voltage conversion part so as to output voltage through the voltage conversion part to supply power to the battery management part. The disclosure also provides a battery management system and an electronic device.

Description

Battery management chip, battery management system and electronic equipment

Technical Field

The present disclosure relates to the field of battery management technologies, and in particular, to a battery management chip and a battery management system. Electronic equipment and power supply method.

Background

The BMS System (Battery Management System) refers to a System that manages and controls a Battery. The battery to be managed and controlled may include a lithium battery, and may also include other types of batteries. The main functions of the BMS system include: the state of the battery is monitored in real time, and management and control of the internal state of the battery are realized by detecting external characteristic parameters (such as voltage, current, temperature and the like) of the battery and adopting a proper algorithm. BMS systems are generally powered by the highest voltage of the battery or battery pack. And the modules in the BMS system need to be powered with low voltage, such as 5V, 3.3V, or 1.8V, etc. Therefore, the conventional BMS system also requires a power management system to provide it with a low-voltage power supply. That is, the BMS needs to cooperate with the power management system to work normally, which makes the whole system complicated, numerous components, bulky and costly, and these disadvantages are not good for the development trend of miniaturization and integration of products.

Furthermore, in chinese patent application publication No. CN108964162A, the battery management system uses the power management system of the DC/DC converter to supply power, and in addition to the above disadvantages, the control chip of the DC/DC power unit in the DC/DC converter is directly powered by the battery, that is, the control chip uses high-voltage power as the working power source, so the control chip must be a high-voltage-resistant chip. In this patent application, in addition to supplying power through an external management power supply system, a high-voltage chip is also required, which causes problems such as high power consumption.

In the case of a lithium battery, the safe operation area of the battery is determined by the current, temperature, voltage, and the like of the battery. If the voltage threshold value is exceeded, the battery is overcharged, the battery can be rapidly damaged and explode when the voltage threshold value is exceeded, and the battery can be damaged when the voltage threshold value is continuously discharged. The lithium battery discharges outside a certain temperature range to damage the service life of the battery, the lithium battery which works outside the allowable temperature range for a long time is easy to generate thermal runaway and spontaneous combustion, and even if the thermal runaway is not generated, the organic electrolyte can support combustion. The life of the lithium ion battery may be impaired by large current discharge or rapid charge. These limits also vary depending on the chemical composition of the cell itself. The BMS system is used to ensure that the cells within the managed battery are operated within their safe operating areas. Particularly, a large-scale battery pack composed of a large number of unit cells connected in series is more likely to cause overcharge or overdischarge due to voltage imbalance of the internal unit cells.

SUMMERY OF THE UTILITY MODEL

To solve at least one of the above technical problems and others, the present disclosure provides a battery management chip, a battery management system, and an electronic device.

According to one aspect of the present disclosure, a battery management chip includes:

a voltage conversion part including a step-down DC-DC switching converter, an input end of the voltage conversion part being connected to a battery output voltage, the step-down DC-DC switching converter converting the battery output voltage into a voltage conversion part output voltage and outputting the voltage conversion part output voltage through an output end of the voltage conversion part; and

the battery management part detects and/or controls the battery, and the power supply end of the battery management part is connected with the output end of the voltage conversion part so as to supply power to the battery management part through the voltage output by the voltage conversion part.

According to at least one embodiment of the present disclosure, the battery management part includes an interface circuit, the interface circuit communicates with an MCU external to the battery management chip, and the battery management part transmits and receives information to and from the MCU through the interface circuit, so that the battery management part performs detection and/or management control on the battery,

and the power supply end of the MCU is connected with the output end of the voltage conversion part so as to supply power to the MCU through the voltage output by the voltage conversion part.

According to at least one embodiment of the present disclosure, the battery management part includes a signal processing unit for processing a detection signal of the battery and/or a management control signal of the battery.

According to at least one embodiment of the present disclosure, the battery management part includes a detection voltage input terminal that receives a voltage of each battery in a battery pack formed by N batteries connected in series, where N is an integer greater than 2.

According to at least one embodiment of the present disclosure, the battery management section includes a selection circuit that selects a battery voltage of one battery in the battery pack at one time or selects respective battery voltages of M batteries in the battery pack at one time, thereby obtaining the battery voltage selected by the selection circuit, where 2 ≦ M ≦ N.

According to at least one embodiment of the present disclosure, the battery management part includes a first analog-to-digital converter,

in a case where the selection circuit selects the voltage of one battery in the battery pack at a time, the number of the first analog-to-digital converters is one, so that the battery voltage of the selected one battery is converted into a digital signal by one of the first analog-to-digital converters and supplied to the signal processing unit, and

in a case where the selection circuit selects the respective cell voltages of the M cells in the battery pack at one time, the number of the first analog-to-digital converters is M, so that the respective cell voltages of the selected M cells are converted into digital signals by the M first analog-to-digital converters, respectively, and supplied to the signal processing unit.

According to at least one embodiment of the present disclosure, the battery management part includes a detection current input terminal that receives current information when the battery is charged or discharged.

According to at least one embodiment of the present disclosure, the battery management part includes a second analog-to-digital converter that converts the current information into a digital signal and supplies the digital signal to the signal processing unit.

According to at least one embodiment of the present disclosure, the battery management part includes a battery temperature acquisition unit, by which a temperature value of the battery is obtained and provided to the signal processing unit.

According to at least one embodiment of the present disclosure, the battery management part includes a charge driving unit and a discharge driving unit, and the signal processing unit controls the charge driving unit and the discharge driving unit according to a detection signal of a battery and/or a control signal from an MCU so as to stop or start charging or discharging of the battery.

According to at least one embodiment of the present disclosure, the voltage conversion section further includes an LDO voltage converter that converts the battery output voltage into a voltage conversion section output voltage,

wherein the voltage conversion part is controlled to: the battery output voltage is converted into the voltage conversion part output voltage by the buck-type DC-DC switching converter, or the battery output voltage is converted into the voltage conversion part output voltage by the LDO voltage converter, or the battery output voltage is converted into the voltage conversion part output voltage by the buck-type DC-DC switching converter and the LDO voltage converter.

According to at least one embodiment of the present disclosure, the LDO voltage converter includes an amplifier-based LDO voltage converter and a comparator-based LDO voltage converter, the LDO voltage converter being switchable to be either an amplifier-based LDO voltage converter or a comparator-based LDO voltage converter in order to convert the battery output voltage to a voltage conversion section output voltage.

According to at least one embodiment of the present disclosure, when the battery management chip is in a state of collecting battery information, the voltage conversion part provides the output voltage through the LDO voltage converter or a series connection manner of the buck DC-DC switching converter and the LDO voltage converter, and when the battery management chip is not in a state of collecting battery information, the voltage conversion part provides the output voltage through the buck DC-DC switching converter.

According to at least one embodiment of the present disclosure, the voltage conversion part is controlled by a signal processing unit inside the battery management chip and/or an MCU outside the battery management chip to provide the output voltage through the LDO voltage converter, or through a series connection of the buck DC-DC switching converter and the LDO voltage converter, or through the buck DC-DC switching converter.

According to another aspect of the present disclosure, a battery management system includes: a battery management chip as described above; and the MCU is communicated with the battery management chip through an interface circuit of the battery management part and is powered by the output voltage of the voltage conversion part.

According to at least one embodiment of the present disclosure, the battery management chip further includes a charge control switch and a discharge control switch for controlling charge and discharge of the battery by control signals from a charge driving unit and a discharge driving unit of the battery management chip.

According to yet another aspect of the disclosure, an electronic device includes: a battery or battery pack that powers other components of the electronic device; and a battery management system as described above for controlling the charging or discharging of the battery or battery pack.

According to yet another aspect of the present disclosure, a method of powering a battery management system through a battery management chip includes: receiving a battery output voltage of a battery or a battery pack; carrying out voltage reduction processing on the output voltage of the battery through a voltage reduction type DC-DC switch converter inside the battery management chip; and supplying the voltage after voltage reduction processing to a battery management part as a power supply voltage of the battery management part, wherein the battery management part is integrated in the battery management chip and is used for detecting and/or controlling the battery or the battery pack.

According to at least one embodiment of the present disclosure, the voltage after the voltage reduction processing is further provided to an MCU external to the battery management chip, wherein the MCU and the battery management part communicate with each other to perform detection and/or management control on the battery.

According to at least one embodiment of the present disclosure, the battery output voltage is buck processed by cooperation of a buck DC-DC switching converter and an LDO voltage converter, wherein the buck DC-DC switching converter and the LDO voltage converter are controlled to: the battery output voltage is converted into a stepped-down voltage through the step-down DC-DC switching converter, or the battery output voltage is converted into a stepped-down voltage through the LDO voltage converter, or the battery output voltage is converted into a stepped-down voltage through the step-down DC-DC switching converter and the LDO voltage converter.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the disclosure and together with the description serve to explain the principles of the disclosure.

Fig. 1 is a schematic diagram of a battery management system according to one embodiment of the present disclosure.

Fig. 2 is a schematic diagram of a battery management chip according to one embodiment of the present disclosure.

Fig. 3 is a schematic diagram of a battery management chip according to one embodiment of the present disclosure.

Fig. 4 is a schematic diagram of a voltage conversion part according to an embodiment of the present disclosure.

Fig. 5 is a schematic diagram of a battery management chip according to one embodiment of the present disclosure.

Fig. 6 is a schematic diagram of a voltage conversion section according to an embodiment of the present disclosure.

Fig. 7 is a schematic diagram of a voltage conversion section according to an embodiment of the present disclosure.

Fig. 8 is a schematic diagram of a voltage conversion part according to an embodiment of the present disclosure.

Fig. 9 is a schematic diagram of a voltage conversion section according to an embodiment of the present disclosure.

Fig. 10 is a schematic diagram of a voltage conversion part according to an embodiment of the present disclosure.

Fig. 11 is a schematic diagram of a switching circuit according to one embodiment of the present disclosure.

Detailed Description

The present disclosure will be described in further detail with reference to the drawings and embodiments. It is to be understood that the specific embodiments described herein are for purposes of illustration only and are not to be construed as limitations of the present disclosure. It should be further noted that, for the convenience of description, only the portions relevant to the present disclosure are shown in the drawings.

It should be noted that the embodiments and features of the embodiments in the present disclosure may be combined with each other without conflict. Technical solutions of the present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

Unless otherwise indicated, the illustrated exemplary embodiments/examples are to be understood as providing exemplary features of various details of some ways in which the technical concepts of the present disclosure may be practiced. Accordingly, unless otherwise indicated, features of the various embodiments may be additionally combined, separated, interchanged, and/or rearranged without departing from the technical concept of the present disclosure.

The use of cross-hatching and/or shading in the drawings is generally used to clarify the boundaries between adjacent components. As such, unless otherwise noted, the presence or absence of cross-hatching or shading does not convey or indicate any preference or requirement for a particular material, material property, size, proportion, commonality between the illustrated components and/or any other characteristic, attribute, property, etc., of a component. Further, in the drawings, the size and relative sizes of components may be exaggerated for clarity and/or descriptive purposes. While example embodiments may be practiced differently, the specific process sequence may be performed in a different order than that described. For example, two processes described consecutively may be performed substantially simultaneously or in reverse order to that described. In addition, like reference numerals denote like parts.

When an element is referred to as being "on" or "on," "connected to" or "coupled to" another element, it can be directly on, connected or coupled to the other element or intervening elements may be present. However, when an element is referred to as being "directly on," "directly connected to" or "directly coupled to" another element, there are no intervening elements present. For purposes of this disclosure, the term "connected" may refer to physically, electrically, etc., and may or may not have intermediate components.

For descriptive purposes, the present disclosure may use spatially relative terms such as "below … …," below … …, "" below … …, "" below, "" above … …, "" above, "" … …, "" higher, "and" side (e.g., as in "side wall") to describe one component's relationship to another (other) component as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use, operation, and/or manufacture in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below … …" can encompass both an orientation of "above" and "below". Further, the devices may be otherwise positioned (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

According to one embodiment of the present disclosure, a battery management chip and a battery management system are provided.

Fig. 1 illustrates a battery management system including a battery management chip according to an embodiment of the present disclosure. The following description will be given by taking a lithium battery as an example, but it will be understood by those skilled in the art that the battery may be a single battery, or may be a battery of other types of batteries. For example, as shown in fig. 1, the battery pack is formed by connecting a plurality of batteries in series, such as BAT1, BAT2.

As shown in fig. 1, the battery management system 10 may include a battery management chip 100 and an MCU (micro control unit) 200. The battery management chip 100 can be used for data acquisition and protection of the battery.

Next, the battery management chip 100 of the present disclosure will be explained first. The battery management chip 100 may include a voltage conversion part 110 and a battery management part 120. It should be noted that the voltage conversion unit 110 and the battery management unit 120 are integrated into a chip, so that the battery management unit 120 can be powered by the voltage conversion unit 110 inside the chip, and a power management system outside the chip is not needed to provide low-voltage power.

The voltage converting part 110 may include a step-down DC-DC switching converter, and the input terminal IN of the voltage converting part 110 may be connected with an output voltage of the battery, wherein the output voltage may be a total voltage of the battery pack when the battery pack is IN a form of the battery pack, a partial voltage of the battery pack, or the like. And the output voltage of the battery can be filtered by the RC filter circuit to obtain the voltage VCC. The step-down DC-DC switching converter converts the battery output voltage into a voltage conversion part output voltage and outputs it through an output terminal of the voltage conversion part 110.

The specific form for the voltage converter 110 will be described in detail below.

The battery management part 120 may include a digital signal processing unit 121, a selection circuit 121, a first analog-to-digital converter 122, a second analog-to-digital converter 123, a battery temperature acquisition unit 124, a charge control unit 125, and a discharge control unit 126.

The battery management chip 100 may be used to detect voltage information of the battery pack. The battery management part 120 may include sensing voltage input terminals SENSE1, SENSE2, … …, SENSE that receive a voltage of each battery in a battery pack formed by N batteries connected in series, where N is an integer greater than 2.

The voltage of each battery of the battery pack may be first reduced in noise and interference by a filter circuit composed of Rf1 and Cf1, Rf2 and Cf2, … …, Rfn and Cfn, and then connected to the input terminals SENSE1, SENSE2, … …, SENSE of the battery management chip 100.

The selection circuit 121 may receive a voltage signal of each battery and perform selection. For example, the positive terminal voltage and the negative terminal voltage of one of the batteries are selected at the same time, and sent to the first analog-to-digital converter (ADC1)122 for sampling and quantization, and converted into digital signals; the voltages of the positive terminals and the negative terminals of two or more batteries can be selected at the same time, and sent to the first analog-to-digital converter (ADC1)122 for sampling and quantization, and then converted into digital signals. The converted digital signal is sent to the digital signal processing unit 121.

The battery management chip 100 may be used to detect current information of the battery pack. When the battery pack is charged or discharged, the charging current or the discharging current of the battery generates a voltage drop through the sampling resistor Rsense connected in series in the current loop, and the second analog-to-digital converter (ADC2)123 collects information of the voltage drop generated by the sampling resistor Rsense, so as to obtain the charging or discharging current information of the battery pack, and sends the current information to the digital signal processing unit 121. Thereby, based on the current information, the protection circuit is controlled, and the protection circuit may include a charging control unit 125 and a discharging control unit 126. The charge control unit 125 and the discharge control unit 126 control the charge control power device M _ CHG and the discharge control power device M _ DCH in the current loop of the battery, respectively, so as to control the charge and discharge of the battery pack when the voltage is abnormal. In addition, the current signal of the battery pack can be used for calculating the electric quantity of the battery pack, and the calculation can be realized by a coulometer.

The battery management chip 100 may be used to detect temperature information of the battery pack. The detection of the temperature may be implemented by constituting a series circuit of the constant temperature resistor Rs and the thermistor R _ ntc, wherein one end of the series circuit may be connected to the voltage output terminal of the voltage conversion part 110 and the other end may be grounded, and the detection terminal may be a connection node of the constant temperature resistor Rs and the thermistor R _ ntc. R _ ntc is placed close to the battery pack to ensure that its temperature is close to the temperature of the battery. The thermistor may be a Negative Temperature Coefficient (NTC) thermistor, i.e. the resistance of the thermistor decreases with increasing Temperature. The voltage of the connection node of Rs and R _ ntc is supplied to the battery temperature acquisition unit 124 of the battery management chip 100, and the temperature information of the battery is obtained by the acquired voltage value, the output voltage value of the voltage conversion part 110, and the characteristic (temperature coefficient) in combination with the resistance of R _ ntc. And the temperature information of the battery is transmitted to the digital signal processing unit 121. Thus, when the temperature is abnormal, the charging and discharging of the battery pack can be controlled by controlling the charging control power device M _ CHG and the discharging control power device M _ DCH.

The digital signal processing unit 121 estimates the current state of the battery, such as the capacity of the battery, the state of charge of the battery (the current electric quantity of the battery), and the like, through a model algorithm according to the obtained battery information, including information such as the voltage, the current, the temperature, and the like of the above battery pack. For example, when an abnormality occurs, the digital signal processing unit 121 may perform control, such as initialization of the system, parameter configuration, execution of a detection function, execution of a protection function, and the like, to ensure that each battery cell operates in a safe region. If the battery is in a charging state, when it is detected that the voltage of one of the battery cells exceeds the set threshold voltage for charge protection, the dsp 121 controls the charge control unit 125 to turn off the external charge control power device M _ CHG, and stops the charging function to protect the battery. The functions of this part may be completed by the digital signal processing unit 121, may also be completed by the MCU200, and may also be completed by the cooperation of the digital signal processing unit 121 and the MCU 200. In addition, the digital signal processing unit 121 may pass through the interface circuit I²C completes communication with the MCU200, and the digital signal processing unit 121 may also perform the above processing through a control signal of the MCU 200.

According to the embodiment of the present disclosure, the power supply terminal of the MCU200 is connected to the voltage output terminal of the voltage conversion part 110, and the MCU200 is directly powered by the output voltage of the voltage conversion part 110. This can effectively reduce power consumption and the requirements on the MCU200 itself.

The voltage conversion part 110 may include a Buck-type DC-DC switching converter, which may be a Buck power converter or a switched capacitor voltage converter, for example. The voltage conversion section 110 may include a Buck DC-DC switching converter, which may be a Buck power converter or a switched capacitor voltage converter, for example, and LDO voltage converter combination circuit.

As an example, fig. 2 shows a case where the voltage conversion section 110 is a Buck power converter. Under the condition that adopts Buck power converter, the on-off control of accessible high frequency and the filtering of inductance and electric capacity, realize the function of step-down, and because Buck power converter's efficiency can reach 90% even higher usually, consequently this lithium cell group's battery management chip's power conversion efficiency will be greater than traditional lithium cell group's battery management chip far away, in addition, the battery management chip that the battery management chip of the lithium cell group of adoption Buck power converter's battery management chip that generates heat will be less than traditional framework far away, therefore this lithium cell group's battery management chip has lower temperature, longer life-span and higher reliability.

As shown in fig. 2, the input terminal of the Buck power converter may be connected to the voltage of the battery pack (as in fig. 1) as an input voltage, and the output terminal thereof outputs the voltage VOUT through the connection point of the inductor and the capacitor connected in series, and the output voltage may be used as a feedback voltage. Meanwhile, the output voltage VOUT serves as a supply voltage for a battery management section inside the chip and also as a supply voltage for an MCU outside the chip.

As an example, fig. 3 shows a case where the voltage conversion section 110 is a switched capacitor voltage converter. As shown in fig. 3, the switched capacitor voltage converter includes a control module of the switched capacitor voltage converter and m external capacitors, where m is a positive integer and is greater than or equal to 1, C1, … …, Cm-1, and Cm. The capacitance selection is controlled by the switching control in the control module of the switched capacitor voltage converter, thereby achieving voltage conversion.

When the switched capacitor voltage converter is used for voltage reduction conversion, input voltage is added to the capacitors connected in series in a certain time period, and the capacitors are connected to the output in parallel in another time period, so that voltage reduction conversion of a power supply is realized, and output current larger than the input current is provided to improve efficiency.

As shown in fig. 3, the input terminal of the control module of the switched capacitor voltage converter is connected to the voltage of the battery pack (as in fig. 1) as an input voltage, and the output voltage VOUT of the output terminal thereof may be used as a feedback voltage. Meanwhile, the output voltage VOUT serves as a supply voltage for a battery management section inside the chip and also as a supply voltage for an MCU outside the chip.

Fig. 4 shows a specific example of a switched capacitor voltage converter. In this example, the number of the capacitors of the switched capacitor voltage converter is 3, the control module of the switched capacitor voltage converter may include ten switches, one end of the first switch K1 serves as an input terminal of the control module of the switched capacitor voltage converter, the other end of the first switch K1 is connected with one end of the second switch K2 and one end of the first capacitor C1, the other end of the second switch K2 is connected with one end of the fourth switch K4, one end of the sixth switch K6 and one end of the tenth switch K10, and serves as an output terminal and a feedback terminal of the control module of the switched capacitor voltage converter.

One end of the third switch K3 is connected to one end of the fifth switch K5, one end of the tenth switch K10, and the ground, and the other end of the third switch K3 is connected to the other end of the first capacitor C1 and one end of the seventh switch K7.

The other end of the fourth switch K4 is connected to the other end of the seventh switch K7 and one end of the second capacitor C2, the other end of the fifth switch K5 is connected to one end of the eighth switch K8 and the other end of the second capacitor C2, the other end of the sixth switch K6 is connected to the other end of the eighth switch K8 and one end of the third capacitor C3, and the other end of the ninth switch K9 is connected to the other end of the tenth switch K10 and the other end of the third capacitor C3.

The switched capacitor power converter comprises capacitors C1, C2, C3 and Cout and two groups of switches (the first group of switches are K2, K3, K4, K5, K6 and K9, and the second group of switches are K1, K7, K8 and K10). When the first group of switches is turned off and the second group of switches is turned on, the input voltage is applied to the capacitors connected in series by C1, C2, C3 and Cout; when the first set of switches is closed and the second set of switches is open, C1, C2, C3 discharge to Cout. By alternately controlling the two sets of switches, the input power supply can be converted into an output voltage which is not higher than 1/4 times of the input voltage, and meanwhile, the output current is 4 times of the output current, so that the voltage conversion from the input end IN to the output end VOUT is realized.

As an example, fig. 5 shows a case where the voltage conversion part 110 includes a Buck power converter and LDO voltage converter combined circuit.

In fig. 5, VCC is a battery voltage or a filtered battery voltage (as shown in fig. 1), and in this case, the voltage converter 110 is a Buck power converter, an LDO voltage converter, or a combined circuit of the Buck power converter and the LDO voltage converter by controlling the switches S1 to S5.

For example, in the case where S3, S5, and S2 are turned off and S1, S4 are turned on, the voltage conversion section 110 is a Buck power converter. And in the case where S3, S5, and S2 are turned on and S1, S4 are turned off, the voltage converting part 110 is an LDO voltage converter. When S3 and S5 are turned off and S1, S2 and S4 are turned on, the voltage conversion unit 110 is a combined circuit of a Buck power converter and an LDO voltage converter.

The Buck power converter is compared to the LDO voltage converter as follows.

The LDO voltage converter realizes the control function of the output voltage by regulating the current or the resistance of a power device which is connected between the input and the output in series. Its advantages are simple structure, low ripple, low cost and small size, but its disadvantage is low efficiency, especially when the battery voltage (total voltage of battery system) is far higher than the voltage needed by power supply of battery management system. For example, for a battery system with 4 lithium batteries connected in series, if the supply voltage of the battery management system is 3.3V. The LDO voltage converter is adopted to convert the voltage of 4 lithium batteries, namely 3.6 multiplied by 4V into 3.3V, and the efficiency of the LDO voltage converter does not exceed 3.3V/14.4V and 23 percent. Because the voltage converter supplies power to each module in the management chip of the lithium battery pack and external elements, the power efficiency of the whole system does not exceed 23%. The efficiency of the power supply is determined by working conditions and cannot be improved by design, and the improvement modes of reducing the resistance on a lead, increasing a power tube and the like only can enable the efficiency to be close to 23 percent, but cannot break through 23 percent. If the operating current of the battery management system is 10mA, the power loss is 10mA × 14.4V × (1-23%) to 111mW, which will be converted into heat, raising the temperature of the battery management system. For example, in general, the QFN package thermal resistance is 150 ° C/W, and the temperature of the management chip of the lithium battery pack is increased by 111mW × 150 ° C/W-16.7 °. For a system with more lithium battery sections, the power loss is more obvious. For example, for a 16-segment lithium battery system, the power supply efficiency will not be higher than 5.73% for 3.3V/(3.6V × 16), and the power loss will be 10mA × (3.6V × 16-3.3V) ═ 543mW, which may result in a temperature increase of 543mW × 150 ° C/W81 ° C, which is generally unacceptable. Therefore, although the battery management chip of the lithium battery pack of the LDO voltage converter solves the disadvantages of the traditional lithium battery pack that the battery management chip needs an external power management system, the battery management chip also has new disadvantages, namely, low efficiency and large heat generation amount, which can cause the working temperature of the system to rise and reduce the reliability and the service life.

The switching type DC-DC voltage converter such as a Buck power converter is adopted as the voltage converter, the efficiency of power conversion is obviously improved, so that the efficiency of a battery management chip of a lithium battery pack is higher, the use is more flexible, the battery management chip of the lithium battery pack has lower temperature, longer service life and higher reliability, the power conversion efficiency of a battery management system using the battery management chip of the lithium battery pack is greatly improved, and the switching type DC-DC voltage converter also has lower temperature, longer service life and higher reliability.

Accessible high frequency's on-off control and inductance and electric capacity's filtering among the Buck power converter, realize the function of step-down, and because Buck power converter's efficiency can reach 90% even higher usually, consequently, the battery management chip of the lithium cell group of this lithium cell group's battery conversion efficiency will be greater than the battery management chip of LDO voltage converter's lithium cell group far away, in addition, the battery management chip of the lithium cell group that adopts Buck power converter's lithium cell group's battery that generates heat will be less than LDO voltage converter far away, therefore the data acquisition of this lithium cell group and protection chip have lower temperature, longer life-span and higher reliability.

For a Buck power converter, the voltage drop across the power tube is determined by I × Rdson. Under the application condition that the input voltage is far larger than the output voltage, the voltage drop can be far smaller than the voltage drop (VIN-VOUT) of a power tube of the LDO voltage converter under the same application condition, so that the conduction loss of the power tube of the Buck power converter under the same condition is far smaller than that of the LDO voltage converter. Even if additional Buck loss such as switching loss and power loss of an external inductor are added, the efficiency of the system is still far higher than that of the LDO.

The normal working current of a battery management chip of the lithium battery pack and an external load is assumed to be 20 mA. The power loss of the battery management system including the LDO voltage converter was (14.4V-3.3V) × 20mA ═ 222 mW. The power loss of the battery management system including the Buck power converter was 3.3V × 20mA × (1-90%)/90% >, which was 7.3 mW. The Buck power converter condition is much lower than the LDO voltage converter condition.

Power dissipation in a battery management system is typically dissipated in the form of heat generated by the battery management chip of the lithium battery pack, which results in different heat generation for battery management systems using different architectures. The heat generated by the chip is dissipated to the surrounding environment through the package, and the temperature of the chip is increased. For the same package, the greater the heat generated by the chip, the higher the temperature of the chip during normal operation, and the higher the temperature of the chip, the faster the chip ages, the shorter the life, and the lower the reliability.

For a battery system with a large number of batteries connected in series, the advantage of the Buck power converter is more obvious. If the number of the battery sections is 16, the input power voltage VCC of the system is as high as 57.6V × 16V, assuming that the power supply voltage of the battery management chip and the external components of the lithium battery pack is 3.3V and the operating current is 20 mA. The maximum power utilization efficiency of a battery management chip of a lithium battery pack of the LDO voltage converter is 3.3V/57.6V which is 5.7%, the power loss is (57.6V-3.3V). times.20 mA which is 1086mW, while the power utilization efficiency of the battery management chip of the lithium battery pack of the Buck power converter can reach 80% (mainly conduction loss and switching loss of a power device), and the power loss is 3.3 V.times.20 mA/80% × (1-80%) -which is 16.5 mW. Therefore, the Buck scheme can be improved by more than 14 times, and the power loss can be reduced to 1.5% of the traditional scheme, namely, the heat generation is only 1.5% of the LDO scheme.

Compared with the LDO voltage converter, the Buck power converter has certain output ripples due to working characteristics. When input and load are constant, and the power converter stably works, the output current and the output voltage of the LDO power converter are also constant, but when the Buck power converter works, the control module controls the switching of high frequency of the power tube, the working frequency is set to be fsw, and one cycle 1/fsw is divided into 2 time periods during working: on-time and freewheel time. During the on-time, the power tube between the switching terminal SW1 of the control module of the Buck power converter and the input power is turned on, and the voltage of the switching terminal SW1 is close to the input voltage. During the freewheeling time, a power tube between a switching end switch of a control module of the Buck power converter and the ground is conducted, and the voltage of the switching end switch is close to the ground voltage. Therefore, the voltage across the inductor is also a high frequency variable, and the current of the inductor, the output voltage Vout2 of the Buck power converter, is also high frequency fluctuating. Neglecting the parasitic resistance of the capacitor and the inductor, the output ripple of Buck is:

taking a 16-cell system as an example, if L is 330uH, Cout is 10uF, and the operating frequency is 200kHz, the ripple of the output voltage will be: Δ V_OUT＝3.3mV。

Therefore, when the switch type DC-DC voltage converter adopts the Buck power converter, the high-frequency switch control can be realized, the inductance and the capacitance can be filtered, the voltage reduction function is realized, and the efficiency of the Buck power converter can reach 90% or even higher generally, so the power conversion efficiency of the battery management chip of the lithium battery pack is far greater than that of the battery management chip of the lithium battery pack with the LDO, in addition, the heat generation of the battery management chip of the lithium battery pack adopting the Buck power converter is far less than that of the battery management chip of the lithium battery pack with the traditional framework, and therefore the battery management chip of the lithium battery pack has lower temperature, longer service life and higher reliability.

According to the embodiment of the disclosure, when the innovative voltage converter capable of switching between the Buck mode and the LDO mode is adopted, the advantages of the Buck-structured voltage converter and the LDO-structured voltage converter are more flexibly taken into consideration, and the voltage converter is suitable for a battery management system. In addition, according to different application requirements, a user can configure the Buck mode and the LDO mode at will, when the Buck mode is in, the Buck mode has the characteristics of high efficiency and ultralow standby power consumption, and when the Buck mode works in the LDO mode, the Buck mode has the advantage of low ripple waves.

As described above, in the embodiment of the present disclosure, the Buck power converter and the LDO voltage converter of the voltage converting unit 110 can be switched according to actual conditions, for example, when the input voltage is high (e.g., greater than 5V) and/or the input/output voltage difference is high, the Buck power converter can be switched to only use, and vice versa, the LDO voltage converter can be switched to only use. When the output current is large (for example, larger than 2A), the method can be switched to only use the Buck power converter, and the method can be switched to only use the LDO voltage converter. When the system has high requirements on output ripple and/or voltage stabilization, only the LDO voltage converter can be adopted, and conversely, only the Buck power converter can be adopted. When the system has higher requirements on the switching efficiency, the system can be switched to only adopt the Buck power converter, and otherwise, the system can be switched to only adopt the LDO voltage converter. And when the input voltage is high and/or the input/output voltage difference is high and the output current ratio is large, the scheme of the Buck power converter and the LDO voltage converter can be adopted.

It will be appreciated by those skilled in the art that although not illustrated in detail, the switched capacitor voltage converter described above may also be used with an LDO voltage converter, in which case the Buck power converter may be replaced with a switched capacitor voltage converter.

Fig. 6 and 7 show an embodiment according to the present disclosure, in which a Buck power converter or an LDO voltage converter may be selected as the voltage converting section 110. The manner in which the Buck power converter is used is shown in fig. 6, and the manner in which the LDO voltage converter is used is shown in fig. 7.

In this embodiment, the Buck power converter and the LDO voltage converter share an amplifier circuit, a power device, and the like, so as to save the circuit cost to the greatest extent.

The embodiment comprises a Buck driving circuit, an LDO driving circuit, an amplifier (which can also be an amplifier and a compensation circuit), two power devices M1-M2 and four switches S1-S4.

The input end of the amplifier is respectively connected with the reference voltage Vref and the output voltage serving as the feedback voltage Vfb, and the output end of the amplifier is connected with the Buck drive circuit and the LDO drive circuit.

A first output terminal of the Buck driving circuit is connected to the gate of the first power device M1 through the first switch S1, and a second output terminal of the Buck driving circuit is connected to the gate of the second power device M2 through the second switch S2 and to one end of the fourth switch S4.

The output end of the LDO driving circuit is connected to the gate of the first power device M1 through the third switch S3, the drain of the first power device M1 is connected to the battery voltage VCC, the source of the first power device M1 is connected to the drain of the second power device M2, and the other end of the fourth switch S4 may be grounded.

The connection node of the first power device M1 and the second power device M2 is connected with the series circuit of L and Cout to obtain the output voltage VOUT.

As shown in fig. 6, when the first switch S1 and the second switch S2 are closed and the third switch S3 and the fourth switch S4 are opened, the voltage conversion part 110 operates in the Buck mode. As shown in fig. 7, when the first switch S1 and the second switch S2 are open and the third switch S3 and the fourth switch S4 are closed, the voltage conversion part 110 operates in the LDO mode.

In the Buck mode, the first power device M1 and the second power device M2 are controlled by the Buck driving circuit to realize Buck conversion, and in the LDO mode, the first power device M1 is controlled by the LDO driving circuit to realize Buck conversion.

In addition, fig. 8 provides another example in which a Buck power converter or an LDO voltage converter may be selected as the voltage converting section 110, and the main difference of this example from the examples shown in fig. 6 and 7 is that the second power device M2 in the examples of fig. 6 and 7 is replaced with an ESD (Electro-Static discharge) protection circuit, so that cost saving, size reduction, and the like will be effective compared to the examples of fig. 6 and 7.

In fig. 8, the output terminal of the Buck driving circuit is connected to the gate of the first power device M1 via the switch S1, and the output terminal of the LDO driving circuit is connected to the gate of the first power device M1 via the switch S2, the drain of the first power device M1 is connected to the ESD protection circuit, and the ESD protection circuit is connected to the connection node of the first power device M1 to connect the series circuit of L and Cout to obtain the output voltage VOUT.

Fig. 9 provides yet another example in which a Buck power converter or an LDO voltage converter may be selected as the voltage conversion section 110, which differs from the examples shown in fig. 6 and 7 in that the amplifiers in fig. 6 and 7 are replaced with switchable amplifiers and comparators.

According to the example shown in fig. 9, the voltage conversion section 110 may be switched to a Buck power converter, an amplifier-based LDO voltage converter, and a comparator-based LDO voltage converter.

When the LDO voltage converter works in the BUCK power converter mode, the LDO voltage converter has the advantages of being high in efficiency and low in power consumption, when the LDO voltage converter works in the amplifier-based LDO voltage converter mode, the LDO voltage converter can have the advantages of being low in output ripple, and when the LDO voltage converter works in the comparator-based LDO voltage converter mode, the LDO voltage converter not only has the advantages of being fast in response and low in power consumption.

The three modes are switched by switchable amplifier and comparator circuits and switches S1-S4. The switchable amplifier and comparator circuit, which may be switched to either an amplifier mode or a comparator mode, will be described in detail later by way of specific examples.

When S1, S2 is turned off and S3, S4 is turned on, the voltage converting part 110 operates in the Buck power converter mode, when S1, S2 is turned on and S3, S4 is turned off and the switchable amplifier and comparator circuit is switched to the amplifier mode, the voltage converting part 110 operates in the mode of the amplifier-based LDO voltage converter, and when S1, S2 is turned on and S3, S4 is turned off and the switchable amplifier and comparator circuit is switched to the comparator mode, the voltage converting part 110 operates in the mode of the comparator-based LDO voltage converter.

Fig. 10 provides another example of a voltage conversion section according to the present disclosure, according to the example shown in fig. 10, the voltage conversion section 110 may be switched to a Buck power converter, an amplifier-based LDO voltage converter, and a comparator-based LDO voltage converter. This example differs from the example shown in fig. 8 in that the amplifier in fig. 8 is replaced with a switchable amplifier and comparator.

When S1 is turned off and S2 is turned on, the voltage conversion section 110 operates in the Buck power converter mode, when S1 is turned on and S2 is turned off and the switchable amplifier and comparator circuit is switched to the amplifier mode, the voltage conversion section 110 operates in the amplifier-based LDO voltage converter mode, and when S1 is turned on and S2 is turned off and the switchable amplifier and comparator circuit is switched to the comparator mode, the voltage conversion section 110 operates in the comparator-based LDO voltage converter mode.

As one example of the present disclosure, fig. 11 provides a detailed view of a switchable amplifier and comparator circuit.

As shown in fig. 11, the circuit may include a differential comparison circuit (or a differential amplification circuit, hereinafter, only the differential comparison circuit is taken as an example) 10 and a switching circuit 20. Wherein the difference comparison circuit 10 compares Vref and Vfb and outputs the comparison result to the value switching circuit 20.

The switching circuit 20 may include a power device, and a series circuit of a switch, a resistor and a capacitor, wherein the power device may be an MOS transistor, a gate of the MOS transistor is connected to the output of the differential comparison circuit 10, a source of the MOS transistor is used as an output terminal, the output terminal is connected to the Buck driving circuit and the LDO driving circuit, and two ends of the series circuit are respectively connected to the gate and the source of the MOS transistor.

Thus, when the switch in the series circuit is closed, the switchable amplifier and comparator circuit is in the amplifier mode, and when the switch in the series circuit is open, the switchable amplifier and comparator circuit is in the comparator mode. And accordingly may operate in an amplifier-based LDO voltage converter or a comparator-based LDO voltage converter.

Further, the Buck drive circuit is also connected to the output of the switchable amplifier and comparator circuit, and therefore the Buck drive circuit can also operate based on the amplifier or comparator.

In fig. 11, the output terminal of the first current source I1 is connected to the sources of the first MOS transistor T1 and the second MOS transistor T2, and the gates of the first MOS transistor T1 and the second MOS transistor T2 are respectively used as the reference voltage input terminal and the feedback voltage input terminal. The drain of the first MOS transistor T1 is connected to the drain and the gate of the third MOS transistor T3 and the gate of the fourth MOS transistor T4. The sources of the third MOS transistor T3, the fourth MOS transistor T4 and the fifth MOS transistor T5 are all connected to the ground terminal. The drain of the fourth MOS transistor T4 is connected to the drain of the second MOS transistor T2, the gate of the fifth MOS transistor T5 and one end of the switch SW1, the other end of the switch SW1 is connected to the drain of the fifth MOS transistor T5 through a resistor R, a capacitor C and a switch SW2, and the output end of the second current source I2 is connected to the drain of the fifth MOS transistor T5 and serves as the output end.

Wherein, it should be understood by those skilled in the art that it is also possible to use a switch, and the MOS transistor can be replaced by a transistor, etc. In addition, the form of the differential comparator or amplifier may be transformed.

In the present disclosure, the amplifier-based LDO voltage converter or the comparator-based LDO voltage converter may be switched according to practical situations, and when the comparator-based LDO voltage converter is used, power consumption will be reduced by several to tens of times compared to the amplifier-based LDO voltage converter.

In a preferred embodiment of the present disclosure, the voltage converting part provides the output voltage through the LDO voltage converter or through a series connection of the buck DC-DC switching converter and the LDO voltage converter when the battery management chip is in a state of collecting the battery information, and provides the output voltage through the buck DC-DC switching converter when the battery management chip is not in a state of collecting the battery information.

In addition, the voltage conversion part may be controlled by a signal processing unit inside the battery management chip and/or an MCU outside the battery management chip to provide the output voltage through the LDO voltage converter, or through a series connection of the buck DC-DC switching converter and the LDO voltage converter, or through the buck DC-DC switching converter.

By adopting different power supply modes according to different states, the power supply efficiency of the voltage conversion part can be effectively improved, and the required precision can be achieved.

The present disclosure also provides a battery management system, including the battery management chip as described above; and the MCU is communicated with the battery management chip through an interface circuit of the battery management part and is powered by the output voltage of the voltage conversion part.

The battery management system may further include a charge control switch and a discharge control switch for controlling charge and discharge of the battery by control signals from the charge driving unit and the discharge driving unit of the battery management chip.

The present disclosure also provides an electronic device comprising a battery or battery pack that powers other components of the electronic device; and a battery management system as described above for controlling the charging or discharging of the battery or battery pack.

The present disclosure also provides a method for supplying power to a battery management system through a battery management chip, including: receiving a battery output voltage of a battery or a battery pack; carrying out voltage reduction processing on the output voltage of the battery through a voltage reduction type DC-DC switch converter inside the battery management chip; and supplying the voltage after voltage reduction processing to a battery management part as a power supply voltage of the battery management part, wherein the battery management part is integrated in the battery management chip and is used for detecting and/or controlling the battery or the battery pack.

The voltage after the voltage reduction processing is also provided to an MCU outside the battery management chip, wherein the MCU and the battery management part are communicated with each other so as to detect and/or manage and control the battery.

Buck processing the battery output voltage by cooperation of a buck DC-DC switching converter and an LDO voltage converter, wherein the buck DC-DC switching converter and the LDO voltage converter are controlled to: the battery output voltage is converted into a stepped-down voltage through the step-down DC-DC switching converter, or the battery output voltage is converted into a stepped-down voltage through the LDO voltage converter, or the battery output voltage is converted into a stepped-down voltage through the step-down DC-DC switching converter and the LDO voltage converter.

The LDO voltage converter includes an amplifier-based LDO voltage converter and a comparator-based LDO voltage converter, which may be switched to either the amplifier-based LDO voltage converter or the comparator-based LDO voltage converter to convert the battery output voltage to a voltage conversion section output voltage.

The matching manner of the buck DC-DC switching converter and the LDO voltage converter in the power supply method may refer to the description of the battery management chip portion above, and the above described manner and principle are applicable to the power supply method, and for brevity, are not described again here.

In the description herein, reference to the description of the terms "one embodiment/mode," "some embodiments/modes," "example," "specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment/mode or example is included in at least one embodiment/mode or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to be the same embodiment/mode or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments/modes or examples. Furthermore, the various embodiments/aspects or examples and features of the various embodiments/aspects or examples described in this specification can be combined and combined by one skilled in the art without conflicting therewith.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

It will be understood by those skilled in the art that the foregoing embodiments are merely for clarity of illustration of the disclosure and are not intended to limit the scope of the disclosure. Other variations or modifications may occur to those skilled in the art, based on the foregoing disclosure, and are still within the scope of the present disclosure.

Claims

1. A battery management chip, the battery management chip comprising:

2. The battery management chip according to claim 1, wherein the battery management part includes an interface circuit, the interface circuit communicates with an MCU external to the battery management chip, the battery management part transmits and receives information to and from the MCU via the interface circuit, so that the battery management part performs detection and/or management control on the battery,

3. The battery management chip according to claim 2, wherein the battery management part includes a signal processing unit for processing a detection signal of the battery and/or a management control signal of the battery.

4. The battery management chip of claim 3, wherein the battery management section includes a detection voltage input terminal that receives a voltage of each cell in a battery pack formed by N cells connected in series, where N is an integer greater than 2.

5. The battery management chip according to claim 4, wherein the battery management section includes a selection circuit that selects a cell voltage of one cell in the battery pack at a time or selects respective cell voltages of M cells in the battery pack at a time, thereby obtaining the cell voltage selected by the selection circuit, wherein 2. ltoreq. M.ltoreq.N.

6. The battery management chip of claim 5, wherein the battery management portion comprises a first analog-to-digital converter,

7. The battery management chip of claim 3, wherein the battery management part comprises a detection current input terminal that receives current information when the battery is charged or discharged.

8. The battery management chip of claim 7, wherein the battery management part comprises a second analog-to-digital converter, and the second analog-to-digital converter converts the current information into a digital signal and supplies the digital signal to the signal processing unit.

9. The battery management chip according to claim 3, wherein the battery management section includes a battery temperature acquisition unit by which a temperature value of the battery is obtained and the temperature value is supplied to the signal processing unit.

10. The battery management chip according to claim 3, wherein the battery management section includes a charge driving unit and a discharge driving unit, and the signal processing unit controls the charge driving unit and the discharge driving unit according to a detection signal of a battery and/or a control signal from the MCU so as to stop or start charging or discharging of the battery.

11. The battery management chip of any of claims 1 to 10, wherein the voltage conversion portion further comprises an LDO voltage converter that converts the battery output voltage to a voltage conversion portion output voltage,

12. The battery management chip of claim 11, wherein the LDO voltage converter comprises an amplifier-based LDO voltage converter and a comparator-based LDO voltage converter, the LDO voltage converter being switchable into either an amplifier-based LDO voltage converter or a comparator-based LDO voltage converter to convert the battery output voltage to a voltage conversion section output voltage.

13. The battery management chip of claim 11, wherein the voltage conversion part provides the output voltage through the LDO voltage converter or through a series connection of a buck DC-DC switching converter and the LDO voltage converter when the battery management chip is in a state of collecting battery information, and provides the output voltage through the buck DC-DC switching converter when the battery management chip is not in a state of collecting battery information.

14. The battery management chip of claim 12, wherein the voltage conversion part provides the output voltage through the LDO voltage converter or through a series connection of a buck DC-DC switching converter and the LDO voltage converter when the battery management chip is in a state of collecting battery information, and provides the output voltage through the buck DC-DC switching converter when the battery management chip is not in a state of collecting battery information.

15. The battery management chip according to claim 13 or 14, wherein the voltage conversion part is controlled by a signal processing unit inside the battery management chip and/or an MCU outside the battery management chip to provide the output voltage through the LDO voltage converter, or through a series connection of a buck DC-DC switching converter and the LDO voltage converter, or through a buck DC-DC switching converter.

16. A battery management system, comprising:

the battery management chip of any one of claims 1 to 15; and

and the MCU is communicated with the battery management chip through an interface circuit of the battery management part and is powered by the output voltage of the voltage conversion part.

17. The battery management system of claim 16, further comprising a charge control switch and a discharge control switch for controlling the charge and discharge of the battery by control signals from a charge driving unit and a discharge driving unit of the battery management chip.

18. An electronic device, comprising:

a battery or battery pack that powers other components of the electronic device; and

a battery management system as claimed in claim 16 or 17 for controlling the charging or discharging of the battery or batteries.