Voltage regulation circuit and battery management system

Abstract

The invention provides a voltage regulation circuit and a battery management system, and the voltage regulation circuit comprises a bias current generation module which is used for generating a bias current related to a voltage change range of a power supply end according to a voltage value of the power supply end; each stage of current modulation module is provided with a first modulation branch circuit and a second modulation branch circuit which are coupled with each other, each second modulation branch circuit has a preset modulation coefficient, and the first modulation branch circuit and the second modulation branch circuit are used for modulating the bias current according to the preset modulation coefficient when the bias current changes. Modulating a difference value between a first current input to the first modulation branch and a second current output to the next-stage current modulation module on the second modulation branch so as to generate a modulation current on the second modulation branch, and inputting the bias current to the first modulation branch of the first-stage current modulation module; and the voltage generation module is used for adjusting the reference current and generating an output voltage. By adopting the technical scheme, the stability of the output voltage can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power management, and in particular to a voltage regulating circuit and a battery management system. Background Art

[0002] Battery Management System (BMS) is a key technology to ensure safe and efficient operation of batteries. It plays a vital role in many fields such as electric vehicles (EVs), energy storage systems, drones, power tools, etc.

[0003] During actual operation, the output voltage of the battery management system changes due to fluctuations in the power supply, which will seriously affect the operating stability.

[0004] Therefore, how to provide a technical solution to improve the stability of the output voltage has become an urgent problem to be solved. Summary of the invention

[0005] In view of this, the present invention provides a voltage regulation circuit and a battery management system, which can improve the stability of the output voltage.

[0006] The present invention provides a voltage regulating circuit, coupled to a power supply terminal, comprising:

[0007] A bias current generating module, used for generating a bias current related to a voltage variation range of the power supply terminal according to a voltage value of the power supply terminal;

[0008] A multi-stage current modulation module, wherein the current modulation modules of each stage are coupled in sequence, and the first stage current modulation module in the multi-stage current modulation module is coupled to the bias current generating module, wherein each stage current modulation module has a first modulation branch and a second modulation branch coupled to each other, and each second modulation branch has a preset modulation coefficient, wherein the first modulation branch and the second modulation branch in any stage current modulation module are used to modulate the difference between the first current input to the first modulation branch and the second current output to the next stage current modulation module on the second modulation branch according to the preset modulation coefficient when the bias current changes, so as to generate a modulation current on the second modulation branch, and input the modulation current to the first modulation branch of the next stage current modulation module through the second modulation branch, and the second modulation branch of the last stage current modulation module outputs a reference current, wherein the bias current is input to the first modulation branch of the first stage current modulation module;

[0009] The voltage generating module is coupled to the current modulating module of the last stage and is used for adjusting the reference current to generate an output voltage.

[0010] Optionally, each current modulation module comprises: a first bipolar transistor and a second bipolar transistor arranged on the first modulation branch, a third bipolar transistor, a fourth bipolar transistor and a current output resistor arranged on the second modulation branch, and a first current mirror unit connected to the second modulation branch, wherein:

[0011] The first bipolar transistor, the second bipolar transistor, the third bipolar transistor and the fourth bipolar transistor constitute current modulation units of current modulation modules of various levels, wherein the base current of the first bipolar transistor is different from the base current of the fourth bipolar transistor, and the current modulation unit is used to generate a modulation current on the second modulation branch according to a current difference between the first current and the second current, and a ratio between the current difference and the collector current of the second bipolar transistor and the preset modulation coefficient when the bias current changes, wherein the preset modulation coefficient is a current amplification factor of the third bipolar transistor;

[0012] The first current mirror unit is used to perform mirror processing on the modulation current on the corresponding second modulation branch to generate a first mirror current, and the first mirror current of the last-stage current modulation module is the reference current.

[0013] Optionally, the first bipolar transistor, the second bipolar transistor, the third bipolar transistor and the fourth bipolar transistor in current modulation modules of different levels are matched, and the current output resistances in current modulation modules of different levels are matched.

[0014] Optionally, the base of the first bipolar transistor is connected to the base of the third bipolar transistor and the collector of the first bipolar transistor, and the emitter of the first bipolar transistor is connected to the base of the fourth bipolar transistor and the collector of the second bipolar transistor;

[0015] The base of the second bipolar transistor is connected to the emitter of the third bipolar transistor and the collector of the fourth bipolar transistor respectively, and the emitter of the second bipolar transistor is connected to the second end of the current output resistor and is grounded;

[0016] The collector of the third bipolar transistor is connected to the first current mirror unit;

[0017] An emitter of the fourth bipolar transistor is connected to the first end of the current output resistor.

[0018] Optionally, the first current mirror unit includes a first mirror transistor and a second mirror transistor, the control end of the first mirror transistor is respectively connected to the control end of the second mirror transistor, the second end of the first mirror transistor and the second modulation branch, the first end of the first mirror transistor is connected to the first end of the second mirror transistor and connected to the power supply end; the second end of the second mirror transistor is used to output the first mirror current.

[0019] Optionally, the voltage generating module comprises: a second mirror unit and a voltage generating unit, wherein:

[0020] The second mirror unit is coupled to the current modulation module and the voltage generation unit of the last stage respectively, and is used to mirror the reference current and feed it back to the voltage generation unit;

[0021] The voltage generating unit is used to adjust the reference current, convert the type of the reference current, generate the output voltage, and output the output voltage.

[0022] Optionally, the second mirror unit includes: a fifth bipolar transistor and a sixth bipolar transistor, wherein:

[0023] The base of the fifth bipolar transistor is respectively connected to the base of the sixth bipolar transistor and the collector of the sixth bipolar transistor, the collector of the fifth bipolar transistor is respectively connected to the current modulation module and the voltage generating unit of the last stage, the emitter of the fifth bipolar transistor is connected to the emitter of the sixth bipolar transistor and is grounded.

[0024] Optionally, the voltage generating unit comprises a gate switch and a first conversion resistor, wherein a control end of the gate switch is connected to the second mirror unit, a first end of the gate switch is connected to the power supply end, and a second end of the gate switch is connected to a first end of the first conversion resistor and serves as an output end;

[0025] The second end of the first conversion resistor is connected to the second mirror unit.

[0026] Optionally, the voltage generating unit also includes: a reference voltage branch located between the selection switch and the conversion resistor, the reference voltage module branch includes a second conversion resistor and a seventh bipolar transistor, wherein the first end of the second conversion resistor is coupled to the second end of the selection switch, the second end of the second conversion resistor is respectively connected to the collector and the base of the seventh bipolar transistor, and the emitter of the seventh bipolar transistor is connected to the first end of the first conversion resistor.

[0027] Optionally, the voltage regulation circuit further includes at least one of the following:

[0028] a first capacitor coupled to the input terminal of the voltage generating unit and the output terminal of the last-stage current modulation module respectively;

[0029] An output capacitor is coupled between the output terminal of the voltage generating unit and ground.

[0030] Optionally, the bias current generating module includes a bias resistor.

[0031] Accordingly, the present invention also provides a battery management system, comprising a voltage regulating circuit as described in any of the above examples.

[0032] Compared with the prior art, the technical solution of the embodiment of the present invention has the following advantages:

[0033] By using the voltage regulation circuit provided by the embodiment of the present invention, the bias current generation module generates a bias current related to the voltage variation range of the power supply end. When the voltage variation range of the power supply end is large, the variation range of the bias current is large. By making each second modulation branch in the multi-stage current modulation module have a preset modulation coefficient, the first modulation branch and the second modulation branch in any one-stage current modulation module can modulate the difference between the first current input to the first modulation branch and the second current output to the next-stage current modulation module on the second modulation branch according to the preset modulation coefficient when the bias current changes, and then through multiple modulations, the influence of the voltage variation range of the power supply end on the reference current can be gradually reduced. In other words, by performing multi-stage regulation on the bias current that produces a change based on the preset modulation coefficient, the influence of the voltage change of the power supply end on the reference current output by the last-stage current modulation module can be greatly suppressed, and the stability of the reference current is higher, thereby improving the stability of the output voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments of the present invention or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 is a schematic structural diagram of a voltage regulation circuit in an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the structure of a current modulation module in an embodiment of the present invention;

[0037] Figure 3 It is a schematic diagram of the derivation principle of a multi-stage suppression principle in an embodiment of the present invention;

[0038] Figure 4 The figure is a schematic diagram of a specific structure of a voltage regulating circuit in an embodiment of the present invention. DETAILED DESCRIPTION

[0039] As described in the background technology, when the power supply end fluctuates, the output voltage of the battery management system changes. This is because: the voltage regulation circuit in the existing solution uses bipolar transistors, and the base current is directly ignored when determining the generated reference current. This approach is sufficient when the circuit power consumption is large, the temperature variation range of the power supply end is small, and the current gain of the bipolar transistor is large. However, when one of the above three conditions is not met, the reference current has a large deviation, so that the output voltage varies more under PVT (i.e., process, voltage and temperature), and thus cannot meet the output requirements.

[0040] For example, when the voltage at the power supply end changes by more than 10 times (for example, the voltage conversion range at the power supply end is 10V to 100V), and the current gain of the bipolar transistor is small, the base currents of two of the bipolar transistors will be inconsistent. In the existing solution, when the base currents of the two bipolar transistors are the same, the base current is ignored, and it is inferred that the reference current is not affected by the voltage change at the power supply end. In actual applications, the inventors found that if the base current is directly ignored, the reference current will follow the voltage change at the power supply end, and the stability of the output voltage will be poor.

[0041] In order to solve the above technical problems, an embodiment of the present invention provides a voltage regulation circuit, which is coupled to a power supply terminal, and includes: a bias current generating module, which is used to generate a bias current related to the voltage variation range of the power supply terminal according to the voltage value of the power supply terminal; a multi-level current modulation module, each level of the current modulation module is coupled in sequence, and the first level of the current modulation module in the multi-level current modulation module is coupled to the bias current generating module, wherein each level of the current modulation module has a first modulation branch and a second modulation branch coupled to each other, and each second modulation branch has a preset modulation coefficient, wherein the first modulation branch and the second modulation branch in any level of the current modulation module are used to generate a bias current related to the voltage variation range of the power supply terminal according to the voltage value of the power supply terminal; and a multi-level current modulation module, wherein the current modulation modules at each level are coupled in sequence, and the first level of the current modulation module in the multi-level current modulation module is coupled to the bias current generating module, wherein the current modulation modules at each level have a first modulation branch and a second modulation branch coupled to each other, and each second modulation branch has a preset modulation coefficient, wherein the first modulation branch and the second modulation branch in any level of the current modulation module are used to generate a bias current related to the voltage variation range of the power supply terminal according to the voltage value of the power supply terminal. When the bias current changes, according to the preset modulation coefficient, the difference between the first current input to the first modulation branch and the second current output to the next-stage current modulation module on the second modulation branch is modulated to generate a modulation current on the second modulation branch, and the modulation current is input to the first modulation branch of the next-stage current modulation module through the second modulation branch, and the second modulation branch of the last-stage current modulation module outputs a reference current, wherein the bias current is input to the first modulation branch of the first-stage current modulation module; a voltage generating module is coupled to the last-stage current modulation module, and is used to adjust the reference current to generate an output voltage

[0042] By using the voltage regulation circuit in the above embodiment, the bias current generating module generates a bias current related to the voltage variation range of the power supply end. When the voltage variation range of the power supply end is large, the variation range of the bias current is large. By making each second modulation branch in the multi-stage current modulation module have a preset modulation coefficient, the first modulation branch and the second modulation branch in any one-stage current modulation module can modulate the difference between the first current input to the first modulation branch and the second current output to the next-stage current modulation module on the second modulation branch according to the preset modulation coefficient when the bias current changes, and then through multiple modulations, the influence of the voltage variation range of the power supply end on the reference current can be gradually reduced. In other words, by performing multi-stage regulation on the bias current that produces a change based on the preset modulation coefficient, the influence of the voltage change of the power supply end on the reference current output by the last-stage current modulation module can be greatly suppressed, and the stability of the reference current is higher, thereby improving the stability of the output voltage.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are exemplarily described below in conjunction with the accompanying drawings.

[0044] For ease of understanding, the following takes the voltage regulation circuit having two current modulation modules as an example to describe in detail the structure and working principle of the voltage regulation circuit in the embodiment of the present invention.

[0045] The present invention provides a voltage regulating circuit, such as Figure 1 The schematic diagram of the structure of a voltage regulating circuit in the present invention is shown, and the voltage regulating circuit may include:

[0046] A bias current generating module 110, configured to generate a bias current related to a voltage variation range of the power supply terminal according to a voltage value of the power supply terminal VDD;

[0047] A multi-level current modulation module (for example, a first-level current modulation module 121 and a second-level current modulation module 122), each level of the current modulation module is coupled in sequence (for example, the first-level current modulation module 121 is coupled to the second-level current modulation module 122, and the second-level current modulation module 122 is coupled to the third-level current modulation module), and the first-level current modulation module 121 in the multi-level current modulation module is coupled to the bias current generating module 110, wherein each level of the current modulation module has a first modulation branch S1 and a second modulation branch S2 coupled to each other, each second modulation branch S2 has a preset modulation coefficient β, wherein any level of the current modulation module The first modulation branch S1 and the second modulation branch S2 in the modulation module are used to modulate the difference between the first current input to the first modulation branch S1 and the second current output to the next-stage current modulation module on the second modulation branch S2 according to the preset modulation coefficient β when the bias current changes, so as to generate a modulation current on the second modulation branch S2, and input the modulation current to the first modulation branch S1 of the next-stage current modulation module through the second modulation branch S2, and the second modulation branch S2 of the last-stage current modulation module outputs a reference current, wherein the bias current is input to the first modulation branch S1 of the first-stage current modulation module 121;

[0048] The voltage generating module 130 is coupled to the current modulating module of the last stage, and is used to adjust the reference current to generate an output voltage.

[0049] Specifically, when the voltage of the power supply terminal VDD fluctuates within a variation range, the bias current generated by the bias current generating module 110 varies with the voltage variation range of the power supply terminal VDD. The variation range of the bias current is large, and the value of the bias current is unstable.

[0050] The current of the first modulation branch S1 of the first-stage current modulation module 121 is a bias current. After being modulated by the first modulation branch S1 and the second modulation branch S2 of the first-stage current modulation module 121, the current difference between the first modulation branch S1 and the second modulation branch S2 is affected by the power supply terminal VDD by 1 / β of the original value. After being modulated by the first modulation branch S1 and the second modulation branch S2 of the second-stage current modulation module 122, the current difference between the first modulation branch S1 and the second modulation branch S2 is further affected by the power supply terminal VDD, and the degree of reduction is related to β. Since the current difference between the first modulation branch S1 and the second modulation branch S2 affects the reference current output by the last-stage current modulation module, the influence of the change of the power supply terminal VDD on the reference current is reduced through multi-stage suppression, and the reference current is more stable.

[0051] In other words, the influence of the voltage change of the power supply terminal VDD on the voltage regulation circuit is gradually reduced. As more cascade-connected current modulation modules are set, the influence of the power supply terminal VDD on the voltage regulation circuit is 1 / β of the original n When n (where n is the number of current modulation modules) is large enough, the influence of the voltage change of the power supply terminal VDD on the voltage regulation circuit can be ignored, so that the stability of the reference current is higher, thereby improving the stability of the output voltage.

[0052] It should be noted that, first, Figure 1 The structure of the voltage regulation circuit shown is only an example to illustrate that a multi-stage current modulation module can be set to reduce the impact of the voltage change at the power supply end on the output voltage; second, Figure 1 A two-stage current modulation module is taken as an example for description. In practical applications, more stages of current modulation modules may be provided. The present invention does not impose any limitation on the number of current modulation modules.

[0053] In this embodiment, bias current generating modules with different structures may be used to convert the voltage at the power supply end into a corresponding bias current.

[0054] As an optional example, the bias current generating module may include a bias resistor, wherein a first end of the bias resistor is connected to a power supply end, and a second end of the bias resistor is connected to the first-stage current modulation module for providing a bias current.

[0055] By using a bias resistor as a bias current generating module, the structure is simple and the overall volume of the voltage regulating circuit can be reduced.

[0056] In this embodiment, the resistance of the bias resistor is generally large, which can reduce the impact of changes in the power supply voltage on the reference current, thereby outputting a more stable voltage to power other equipment, circuits or devices.

[0057] In some other embodiments, the bias current generating module may also be other devices capable of converting voltage into current.

[0058] In this embodiment, in order to reduce the influence of the voltage at the power supply end on the reference current, the structures of the first modulation branch and the second modulation branch may be adaptively adjusted.

[0059] For example, combined with Figure 1 , see Figure 2 A structural diagram of a current modulation module is shown in FIG. Figure 2 As shown, each level of current modulation module (for example, the first-level current modulation module 121 and the second-level current modulation module 122) includes: a first bipolar transistor Q1 and a second bipolar transistor Q2 arranged on the first modulation branch S1, a third bipolar transistor Q3, a fourth bipolar transistor Q4 and a current output resistor R2 arranged on the second modulation branch S2, and a first current mirror unit CM1 connected to the second modulation branch S2.

[0060] In this embodiment, the first bipolar transistor Q1, the second bipolar transistor Q2, the third bipolar transistor Q3 and the fourth bipolar transistor Q4 constitute current modulation units of current modulation modules at each level, wherein the base current of the first bipolar transistor Q1 is different from the base current of the fourth bipolar transistor Q4, so that when determining the reference current, the base current difference between the first bipolar transistor Q1 and the fourth bipolar transistor Q4 cannot be ignored, so that when the voltage at the power supply end changes, the reference current changes.

[0061] Based on this, the current modulation unit is used to generate a modulation current on the second modulation branch when the bias current changes (or it can be considered that the power supply end changes), according to the current difference between the first current and the second current, and the ratio between the current difference and the collector current of the second bipolar transistor and the preset modulation coefficient, wherein the preset modulation coefficient is the current gain factor of the third bipolar transistor.

[0062] Specifically, for any current modulation module, the current difference between the first current and the second current can be modulated by the first bipolar transistor Q1, the second bipolar transistor Q2, the third bipolar transistor Q3 and the fourth bipolar transistor Q4, and in the modulation process, the preset modulation coefficient β is the current amplification factor of the third bipolar transistor Q3, so that while reducing the influence of the power supply terminal VDD, the bias current on the first modulation branch S1 and the current on the second modulation branch S2 tend to be the same (the difference between the two is very small, close to 0), so that the final output reference current can be unaffected by the power supply terminal VDD, and the reference current is more stable.

[0063] In this case, the first current mirror unit can be used to perform mirror processing on the modulation current on the corresponding second modulation branch to generate a first mirror current, and the first mirror current of the last-stage current modulation module is the reference current.

[0064] For example, the first current mirror unit CM1 can mirror the current on the second modulation branch in the first-level current modulation module, the first current mirror unit CM1_A can mirror the current on the second modulation branch in the second-level current modulation module, and so on. The last first current mirror unit can mirror the current on the second modulation branch in the last-level current modulation module as a reference current output.

[0065] In this embodiment, the first bipolar transistor Q1, the second bipolar transistor Q2, the third bipolar transistor Q3 and the fourth bipolar transistor Q4 in different levels of current modulation modules are matched, and the current output resistors R2 in different levels of current modulation modules are matched, so that the current modulation modules at each level have the same characteristics (such as temperature change characteristics, resistance change characteristics), which can reduce the errors caused by the differences in the current modulation modules at each level and can further improve the stability of the output voltage.

[0066] It should be noted that the matching in this embodiment means that: the first bipolar transistors Q1 in the current modulation modules of different levels are the same, the second bipolar transistors Q2 in the current modulation modules of different levels are the same, the third bipolar transistors Q3 in the current modulation modules of different levels are the same, the fourth bipolar transistors Q4 in the current modulation modules of different levels are the same, and the current output resistors R2 in the current modulation modules of different levels are the same, wherein "same" means the type of bipolar transistors is the same, the type of current output resistors R2 is the same, the temperature coefficient / temperature dependence is the same, the manufacturing process is the same, the wafer is the same, the manufacturing time is the same and / or the position layout is the same, such a matching mechanism can compensate for process changes and provide the same component temperature dependence.

[0067] In this embodiment, the connection relationship between the first modulation branch S1 and the second modulation branch S2 is:

[0068] The base of the first bipolar transistor Q1 is connected to the base of the third bipolar transistor Q3 and the collector of the first bipolar transistor Q1, and the emitter of the first bipolar transistor Q1 is connected to the base of the fourth bipolar transistor Q4 and the collector of the second bipolar transistor Q2;

[0069] The base of the second bipolar transistor Q2 is connected to the emitter of the third bipolar transistor Q3 and the collector of the fourth bipolar transistor Q4 respectively, and the emitter of the second bipolar transistor Q2 is connected to the second end of the current output resistor R2 and is grounded;

[0070] The collector of the third bipolar transistor Q3 is connected to the first current mirror unit CM1;

[0071] An emitter of the fourth bipolar transistor Q4 is connected to a first end of the current output resistor R2 .

[0072] It should be noted that the structures connected to the collectors of the first bipolar transistors Q1 in the current modulation modules at different stages are different.

[0073] For example, the collector of the first bipolar transistor Q1 in the first-stage current modulation module is connected to the output end of the bias current generation module 110, for example, the collector of the first bipolar transistor Q1 is connected to the first end of the bias resistor R1; and the collector of the first bipolar transistor Q1 in the current modulation module of other stages is connected to the output end of the first mirror unit CM1 of the current modulation module of the previous stage.

[0074] In this embodiment, by configuring the parameters of the first bipolar transistor Q1 , the second bipolar transistor Q2 , the third bipolar transistor Q3 and the fourth bipolar transistor Q4 , the bias current and the current on the collector of the third bipolar transistor Q3 can be made to be the same.

[0075] In a specific embodiment, the effective sizes of the first bipolar transistor Q1, the second bipolar transistor Q2, and the third bipolar transistor Q3 are the same and are all smaller than the effective size of the fourth bipolar transistor Q4, where the effective size may refer to the area of ​​the bipolar transistor (wherein the effective size may refer to the size of a component on a semiconductor die, for example, the effective size of a bipolar transistor may be increased by stacking in parallel multiple bipolar transistors having a common base, collector, and emitter terminals).

[0076] In an optional example, a ratio between the first bipolar transistor Q1 , the second bipolar transistor Q2 , the third bipolar transistor Q3 , and the fourth bipolar transistor Q4 is 1:1:1:8.

[0077] It should be noted that, first, Figure 2 The description is made by taking the example that the first bipolar transistor Q1, the second bipolar transistor Q2, the third bipolar transistor Q3 and the fourth bipolar transistor Q4 are of NPN type. In some other embodiments, the first bipolar transistor Q1, the second bipolar transistor Q2, the third bipolar transistor Q3 and the fourth bipolar transistor Q4 may also be of PNP type, and the present invention does not impose any specific limitation on the type of bipolar transistors. Second, the ratio between the first bipolar transistor Q1, the second bipolar transistor Q2, the third bipolar transistor Q3 and the fourth bipolar transistor Q4 may be other values, and this embodiment does not impose any limitation on this.

[0078] In this embodiment, the first current mirror unit CM1 may include a first mirror transistor M1 and a second mirror transistor M2, wherein the control end of the first mirror transistor M1 is respectively connected to the control end of the second mirror transistor M2, the second end of the first mirror transistor M1 and the second modulation branch S2 (for example, the collector of the third bipolar transistor Q3), the first end of the first mirror transistor M1 is connected to the first end of the second mirror transistor M2 and is connected to the power supply end VDD; and the second end of the second mirror transistor M2 is used to output the first mirror current.

[0079] It should be noted that the second end of the second mirror transistor M2 in the current modulation modules at different stages is connected to different structures.

[0080] For example, the second end of the second mirror transistor M2 in the last current modulation module is connected to the voltage generation module 130, and the second end of the second mirror transistor M2 in other current modulation modules is connected to the first modulation branch S1 in the next current modulation module.

[0081] Specifically, by using the mirror module CM1 composed of the first mirror transistor M1 and the second mirror transistor M2, the current on the second modulation branch S2 can be mirrored to generate a current with a corresponding mirror coefficient.

[0082] In an optional embodiment, the mirror coefficient between the first mirror transistor M1 and the second mirror transistor M2 is 2, and the current output by the second mirror transistor M2 is twice the current on the second modulation branch S2.

[0083] It should be noted that, first, Figure 2The structure of the mirror module CM1 is only an example. In practical applications, more mirror transistors may be used, and the embodiment of the present invention does not limit this. Second, Figure 2 The illustrated first mirror transistor M1 and the second mirror transistor M2 are both PMOS transistors. In some other embodiments, the first mirror transistor M1 and the second mirror transistor M2 may both be NMOS transistors. The embodiment of the present invention does not limit the types of the first mirror transistor M1 and the second mirror transistor M2. Third, the mirror coefficient between the first mirror transistor M1 and the second mirror transistor M2 is also an example. Different mirror coefficients may be used in different application scenarios.

[0084] Therefore, by using the current modulation module with the above structure, the influence of the power supply terminal VDD on the reference current can be reduced.

[0085] To facilitate understanding of the multi-stage suppression principle in the embodiment of the present invention, an example is provided below for explanation.

[0086] See also Figure 3 The schematic diagram of the derivation principle of a multi-stage suppression principle in the present invention is shown in FIG. Figure 3 As shown, the derivation process is as follows:

[0087]

[0088] From the above derivation, it can be obtained that the difference between I0 and I1 will be divided by β and reflected between IB_Q4 and IB_Q1, and the value of I0 changes with the power supply terminal VDD. The above method can suppress the temperature influence of the power supply terminal VDD to a certain extent, but when the power supply voltage changes by more than 10 times (10V-100V) and I1 or β is small, this difference cannot be ignored, thereby making the stability of the reference current worse.

[0089] Furthermore, I1 consists of two parts, wherein the first part is a constant value and the second part is affected by I0, and I0 is related to the power supply terminal VDD, so I1 is affected by the power supply terminal VDD. By dividing the difference between I0 and I1 by β, suppressing the difference by β times, and then taking the logarithm, the influence of the power supply terminal VDD can be further reduced.

[0090] By analogy, after two stages, the second part is further suppressed by times, and the suppression ability is related to β. In this way, even if the power supply voltage changes by more than 10 times, the influence of the power supply terminal VDD can be significantly reduced.

[0091] It should be noted that, first, IE_Q1 in the above example represents the emitter current of the first bipolar transistor Q1, IE_Q3 represents the emitter current of the third bipolar transistor Q3, IB_Q4 represents the base current of the fourth bipolar transistor Q4, IB_Q1 represents the base current of the first bipolar transistor Q1, IC_Q1 represents the collector current of the first bipolar transistor Q1, and IC_Q2 represents the collector current of the second bipolar transistor Q2; second, in order to distinguish the bipolar transistors, mirror transistors and current output resistors in the voltage modulation modules of different levels, different reference numbers are used for illustration, for example, the reference numbers of the first bipolar transistor include: Q1 and Q1_A; third, V T represents the thermal voltage of a bipolar transistor, represents the ratio of the effective size of the first bipolar transistor Q3 to the effective size of the second bipolar transistor Q4.

[0092] In summary, the setting of the multi-stage current modulation module greatly suppresses the influence of the voltage change at the power supply end on the reference current output by the last-stage current modulation module, so that the reference current tends to a constant value.

[0093] In this embodiment, the temperature characteristic of the reference current can also be controlled, wherein the temperature characteristic of the reference current depends on the temperature characteristic of the thermal voltage (dV T / dT) and the temperature characteristic of the current output resistance (dR2 / dT), while the temperature characteristic of the thermal voltage is usually a positive constant, that is, it changes positively with temperature. Therefore, the temperature characteristic of the current modulation module used to generate the reference current can be at least one of a PTAT current generator proportional to absolute temperature, a CTAT current generator complementary to absolute temperature, and an independent current generator.

[0094] In an optional example, if the current output resistance is independent of temperature, the current modulation module may be a PTAT current generator.

[0095] In this embodiment, combined with Figures 1 to 3 , see Figure 4 The specific structural diagram of a voltage regulating module shown in FIG. 1 , the voltage generating module 130 may include: a second mirror unit CM2 and a voltage generating unit UG, wherein:

[0096] The second mirror unit CM2 is respectively coupled to the last-stage current modulation module (e.g., the second-stage current modulation module 122) and the voltage generation unit UG, and is used to mirror the reference current and feed it back to the voltage generation unit UG;

[0097] The voltage generating unit UG is used to adjust the reference current, convert the type of the reference current, generate the output voltage Vout, and output the output voltage Vout.

[0098] Specifically, through the second mirror unit CM2, the reference current output by the last-stage current modulation module can be mirrored and fed back, and can be transmitted to the voltage generating unit UG, and then the voltage generating unit UG can adjust the reference current and convert the type of the reference current to generate an output voltage Vout to power the external circuit.

[0099] In some optional embodiments, the second mirror unit CM2 includes: a fifth bipolar transistor Q5 and a sixth bipolar transistor Q6, wherein: the base of the fifth bipolar transistor Q5 is respectively connected to the base of the sixth bipolar transistor Q6 and the collector of the sixth bipolar transistor Q6, the collector of the fifth bipolar transistor Q5 is respectively connected to the last-stage current modulation module (for example, the second-stage current modulation module 122) and the voltage generating unit UG, and the emitter of the fifth bipolar transistor Q5 is connected to the emitter of the sixth bipolar transistor Q6 and grounded.

[0100] In other words, the fifth bipolar transistor Q5 and the sixth bipolar transistor Q6 can mirror the reference current to mirror the reference current, so that the mirrored reference current can be pulled to the voltage generating unit UG.

[0101] In some embodiments, the effective sizes of the fifth bipolar transistor Q5 and the sixth bipolar transistor Q6 may be different (wherein the effective size may refer to the size of a component on a semiconductor die, for example, the effective size of a bipolar transistor may be increased by stacking in parallel multiple bipolar transistors having common base, collector, and emitter terminals).

[0102] In a specific embodiment, the effective size ratio between the fifth bipolar transistor Q5 and the sixth bipolar transistor Q6 is 1:4, that is, the mirror coefficient between the fifth bipolar transistor Q5 and the sixth bipolar transistor Q6 is 4, and the mirror reference current=4*reference current.

[0103] It can be understood that, first, the mirror coefficient between the fifth bipolar transistor Q5 and the sixth bipolar transistor Q6 can also be other values; second, in this embodiment, the fifth bipolar transistor Q5 and the sixth bipolar transistor Q6 are NPN type for illustration, and in some other embodiments, the fifth bipolar transistor Q5 and the sixth bipolar transistor Q6 can also be PNP type.

[0104] In this embodiment, the voltage generating unit UG may include a gate switch M3 and a first conversion resistor R3, wherein the control end of the gate switch M3 is connected to the second mirror unit CM2 (for example, the collector of the fifth bipolar transistor Q5), the first end of the gate switch M3 is connected to the power supply end VDD, the second end of the gate switch M3 is connected to the first end of the first conversion resistor R3 and serves as an output end; the second end of the first conversion resistor R3 is connected to the second mirror unit CM2 (for example, the collector and base of the sixth bipolar transistor Q6).

[0105] Specifically, when the selection switch M3 is turned on, the second mirror unit CM2 can mirror the reference current, so that the mirror current can flow through the first conversion resistor R3, and the output voltage Vout can be obtained after conversion by the first conversion resistor R3.

[0106] Furthermore, in the present embodiment, the sixth bipolar transistor Q6 is connected in a cross-diode manner so that the collector-emitter voltage of the sixth bipolar transistor Q6 is the same as the base-emitter voltage, so that the collector-emitter voltage may include a fixed bandgap voltage and a CTAT voltage component complementary to the absolute temperature, so that the sixth bipolar transistor Q6 has a fixed bandgap voltage of approximately 1.25V, so that the output voltage Vout has an additional fixed bandgap voltage of 1.25V in addition to the voltage on the first conversion resistor R3.

[0107] In this embodiment, the properties (or type) of the fifth bipolar transistor Q5, the sixth bipolar transistor Q6 and the first conversion resistor R3 may be respectively the same as the properties (or type) of the first bipolar transistor Q1, the second bipolar transistor Q2, the third bipolar transistor Q3, the fourth bipolar transistor Q4 and the current output resistor R2.

[0108] In other words, the current output resistor R2 matches the first conversion resistor R3, and the fifth bipolar transistor Q5 and the sixth bipolar transistor Q6 match the first bipolar transistor Q1, the second bipolar transistor Q2, the third bipolar transistor Q3, and the fourth bipolar transistor Q4.

[0109] The matching illustrated here refers to: the same type of bipolar transistors and resistors, the same temperature coefficient / temperature dependence, the same manufacturing process, the same wafer, the same manufacturing time and / or the same position layout. Such a matching mechanism can compensate for process variations and provide the same component temperature dependence.

[0110] In this way, the output voltage Vout of the voltage generating unit UG is insensitive to temperature changes, and because the bipolar transistors and resistors shared by the output branch and the feedback branch are matched, the output branch can provide an output voltage Vout with high accuracy that is insensitive to any changes in process or environment.

[0111] In this embodiment, the gate switch M3 may have a rated voltage higher than the maximum value of the voltage operating range of the power supply terminal VDD, which can improve the stability of the circuit operation.

[0112] In one embodiment, the gate switch M3 is an NMOS transistor. In some other embodiments, the gate switch M3 may also be a PMOS transistor.

[0113] In this embodiment, the voltage generating unit UG may further include: a reference voltage module branch located between the selection switch M3 and the conversion resistor R3, so that the value of the output voltage Vout can be adjusted while keeping the original circuit structure unchanged.

[0114] In a specific embodiment, the reference voltage module branch may include a second conversion resistor R4 and a seventh bipolar transistor Q7, wherein the first end of the second conversion resistor R4 is coupled to the second end of the selection switch M3, the second end of the second conversion resistor R4 is respectively connected to the collector and the base of the seventh bipolar transistor Q7, and the emitter of the seventh bipolar transistor Q7 is connected to the first end of the first conversion resistor R3.

[0115] It should be noted that the number of the reference voltage module branches can be multiple; second, the seventh bipolar transistor Q7 in the reference voltage module branch matches the first bipolar transistor Q1, and the second conversion resistor R4 matches the first conversion resistor R3.

[0116] In some optional examples of the present invention, the voltage regulation circuit may also include a first capacitor C1 coupled to the input end of the voltage generating unit UG and the output end of the last-stage current modulation module (for example, the second-stage current modulation module 122), respectively, so as to provide a stable current value for the voltage regulation circuit.

[0117] Specifically, a first end of the first capacitor C1 is connected to the control end of the gate switch M4 and the collector of the fifth bipolar transistor Q5 respectively, and a second end of the first capacitor C1 is grounded.

[0118] In some optional examples of the present invention, the voltage regulating circuit may further include an output capacitor C2 coupled between the output end of the voltage generating unit UG and the ground, so as to improve the stability of the output voltage Vout.

[0119] Specifically, a first end of the output capacitor C2 is connected to a second end of the gate switch M4, and a second end of the output capacitor C2 is grounded.

[0120] In some embodiments, the capacitance values ​​of the first capacitor C1 and the output capacitor C2 may be in the picofarad level and may be integrated on a chip to maintain the stability of the output voltage in response to load changes.

[0121] It should be noted that the above describes multiple embodiment schemes provided by the present invention. The various optional methods introduced in each embodiment scheme can be combined and cross-referenced with each other without conflict, thereby extending a variety of possible embodiment schemes, which can all be regarded as embodiment schemes disclosed and invented by the present invention.

[0122] In a specific implementation, the voltage regulation circuit can be applied to various batteries and corresponding devices. An application example in a battery management system is given below.

[0123] An embodiment of the present invention further provides a battery management system, comprising the voltage regulating circuit described in any of the above embodiments.

[0124] It should be noted that “one embodiment” or “embodiment” referred to in the present invention refers to specific features, structures or characteristics that may be included in at least one implementation method of the present invention. And in the description of the present invention, the terms “first”, “second”, etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, features defined by the terms “first”, “second”, etc. may explicitly or implicitly include one or more of the features. Moreover, the terms “first”, “second”, etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or to express importance. It is understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than that shown or described.

[0125] Although the embodiments of the present invention are disclosed above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A voltage regulating circuit, coupled to a power supply terminal, characterized in that: include: A bias current generating module, configured to generate a bias current related to a voltage variation range of the power supply terminal according to a voltage value of the power supply terminal; A multi-stage current modulation module, wherein the current modulation modules of each stage are coupled in sequence, and the first stage current modulation module in the multi-stage current modulation module is coupled to the bias current generating module, wherein each stage current modulation module has a first modulation branch and a second modulation branch coupled to each other, and each second modulation branch has a preset modulation coefficient, wherein the first modulation branch and the second modulation branch in any stage current modulation module are used to modulate the difference between the first current input to the first modulation branch and the second current output to the next stage current modulation module on the second modulation branch according to the preset modulation coefficient when the bias current changes, so as to generate a modulation current on the second modulation branch, and input the modulation current to the first modulation branch of the next stage current modulation module through the second modulation branch, and the second modulation branch of the last stage current modulation module outputs a reference current, wherein the bias current is input to the first modulation branch of the first stage current modulation module; The voltage generating module is coupled to the current modulating module of the last stage and is used for adjusting the reference current to generate an output voltage.

2. The voltage regulating circuit according to claim 1, characterized in that: Each level of current modulation module includes: a first bipolar transistor and a second bipolar transistor arranged on the first modulation branch, a third bipolar transistor, a fourth bipolar transistor and a current output resistor arranged on the second modulation branch, and a first current mirror unit connected to the second modulation branch, wherein: The first bipolar transistor, the second bipolar transistor, the third bipolar transistor and the fourth bipolar transistor constitute current modulation units of current modulation modules of various levels, wherein the base current of the first bipolar transistor is different from the base current of the fourth bipolar transistor, and the current modulation unit is used to generate a modulation current on the second modulation branch according to a current difference between the first current and the second current, and a ratio between the current difference and the collector current of the second bipolar transistor and the preset modulation coefficient when the bias current changes, wherein the preset modulation coefficient is a current amplification factor of the third bipolar transistor; The first current mirror unit is used to perform mirror processing on the modulation current on the corresponding second modulation branch to generate a first mirror current, and the first mirror current of the last-stage current modulation module is the reference current.

3. The voltage regulating circuit according to claim 2, characterized in that: The first bipolar transistor, the second bipolar transistor, the third bipolar transistor and the fourth bipolar transistor in the current modulation modules of different levels are matched, and the current output resistances in the current modulation modules of different levels are matched.

4. The voltage regulating circuit according to claim 2, characterized in that: The base of the first bipolar transistor is connected to the base of the third bipolar transistor and the collector of the first bipolar transistor respectively, and the emitter of the first bipolar transistor is connected to the base of the fourth bipolar transistor and the collector of the second bipolar transistor respectively; The base of the second bipolar transistor is connected to the emitter of the third bipolar transistor and the collector of the fourth bipolar transistor respectively, and the emitter of the second bipolar transistor is connected to the second end of the current output resistor and is grounded; The collector of the third bipolar transistor is connected to the first current mirror unit; An emitter of the fourth bipolar transistor is connected to the first end of the current output resistor.

5. The voltage regulating circuit according to claim 2, characterized in that: The first current mirror unit includes a first mirror transistor and a second mirror transistor, the control end of the first mirror transistor is respectively connected to the control end of the second mirror transistor, the second end of the first mirror transistor and the second modulation branch, the first end of the first mirror transistor is connected to the first end of the second mirror transistor and connected to the power supply end; the second end of the second mirror transistor is used to output the first mirror current.

6. The voltage regulating circuit according to claim 1, characterized in that: The voltage generating module comprises: a second mirror unit and a voltage generating unit, wherein: The second mirror unit is coupled to the current modulation module and the voltage generation unit of the last stage respectively, and is used to mirror the reference current and feed it back to the voltage generation unit; The voltage generating unit is used to adjust the reference current, convert the type of the reference current, generate the output voltage, and output the output voltage.

7. The voltage regulating circuit according to claim 6, characterized in that: The second mirror unit comprises: a fifth bipolar transistor and a sixth bipolar transistor, wherein: The base of the fifth bipolar transistor is respectively connected to the base of the sixth bipolar transistor and the collector of the sixth bipolar transistor, the collector of the fifth bipolar transistor is respectively connected to the current modulation module and the voltage generating unit of the last stage, the emitter of the fifth bipolar transistor is connected to the emitter of the sixth bipolar transistor and is grounded.

8. The voltage regulating circuit according to claim 6, characterized in that: The voltage generating unit comprises a gate switch and a first conversion resistor, wherein a control end of the gate switch is connected to the second mirror unit, a first end of the gate switch is connected to the power supply end, and a second end of the gate switch is connected to a first end of the first conversion resistor and serves as an output end; The second end of the first conversion resistor is connected to the second mirror unit.

9. The voltage regulating circuit according to claim 8, characterized in that: The voltage generating unit also includes: a reference voltage branch located between the selection switch and the conversion resistor, the reference voltage module branch includes a second conversion resistor and a seventh bipolar transistor, wherein the first end of the second conversion resistor is coupled to the second end of the selection switch, the second end of the second conversion resistor is respectively connected to the collector and the base of the seventh bipolar transistor, and the emitter of the seventh bipolar transistor is connected to the first end of the first conversion resistor.

10. The voltage regulating circuit according to claim 6, characterized in that: Also includes at least one of the following: a first capacitor coupled to the input terminal of the voltage generating unit and the output terminal of the last-stage current modulation module respectively; An output capacitor is coupled between the output terminal of the voltage generating unit and ground.

11. The voltage regulating circuit according to claim 1, characterized in that: The bias current generating module includes a bias resistor.

12. A battery management system, characterized in that: The method comprises a voltage regulating circuit as claimed in any one of claims 1 to 11.

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