Power supply circuit and power supply equipment

Abstract

The invention relates to the technical field of power electronics, in particular to a power circuit and power equipment, the power circuit comprises a control circuit, a reference current generating circuit and a charging current generating circuit, the control circuit is used for outputting a control signal, and the reference current generating circuit is electrically connected with the control circuit and used for generating reference current in response to the control signal; the charging current generating circuit comprises a plurality of groups of current generating units, each group of current generating units is electrically connected with the reference current generating circuit and the control circuit, the groups of current generating units are connected in parallel and are electrically connected with the battery at parallel connection points, and the target current generating unit responds to control signal generating unit current. The target charging current is output at the parallel connection point to charge the battery, the unit current and the reference current are in a preset proportion, and the target charging current is the sum of the unit currents generated by the target current generation unit. The precision of the charging current can be improved by forming the charging current by the plurality of groups of unit currents proportional to the reference current.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a power supply circuit and a power supply device. Background Art

[0002] At present, when charging the battery through the power circuit, the power circuit can use a variety of charging methods to charge the battery, but the most common charging method is the constant current constant voltage (CCCV) charging mode, because it can take into account the comprehensive advantages of high efficiency, safety, and low cost. CCCV charging mainly goes through constant current charging (which is divided into trickle charging, constant current charging, etc.), constant voltage charging and charging termination.

[0003] In a conventional power supply circuit for charging a battery, a first transistor for setting a reference current and a second transistor for generating a charging current are usually included. The proportional relationship between the second transistor and the first transistor determines the proportional relationship between the reference current and the charging current. Therefore, the required charging current can be obtained by setting the reference current. However, in actual applications, although the size ratio between the second transistor and the first transistor has been determined, due to the difference in the working states of the two transistors, the ratio between the reference current and the charging current usually deviates from the design value, causing the matching accuracy between the reference current and the charging current to deteriorate. Therefore, there is a certain deviation between the actual charging current and the required charging current, which affects the accuracy of the charging current. When the actual charging current is smaller than the required charging current, the charging time will be longer, thereby affecting the charging efficiency. When the actual charging current is larger than the required charging current, the chemical reaction inside the battery will be accelerated, which is easy to cause overheating and trigger potential thermal runaway risks. Summary of the invention

[0004] An object of the present invention is to provide a power supply circuit and a power supply device to solve the technical problem of low charging current accuracy of the power supply circuit in the related art.

[0005] In a first aspect, an embodiment of the present invention provides a power supply circuit, including:

[0006] A control circuit, used for outputting a control signal;

[0007] A reference current generating circuit, electrically connected to the control circuit, for generating a reference current in response to the control signal;

[0008] A charging current generating circuit comprises a plurality of groups of current generating units, each group of the current generating units being electrically connected to the reference current generating circuit and the control circuit respectively, each group of the current generating units being connected in parallel and being configured to be electrically connected to a battery at the parallel connection point, a target current generating unit generating a unit current in response to the control signal to output a target charging current at the parallel connection point to charge the battery, the unit current being in a preset ratio to the reference current, and the target charging current being the sum of the unit currents generated by the target current generating units.

[0009] Optionally, the reference current generating circuit includes:

[0010] A first MOS transistor, comprising a first gate, a first end and a second end, wherein the first gate of the first MOS transistor is electrically connected to the control circuit and each group of the current generating units respectively, and the first end of the first MOS transistor is configured to input an external voltage;

[0011] A first resistor, one end of the first resistor is electrically connected to the second end of the first MOS tube, and the other end of the first resistor is grounded.

[0012] Optionally, the power supply circuit further includes a clamping circuit;

[0013] The clamping circuit is electrically connected to the second end of the first MOS tube and the first resistor respectively, and is electrically connected to each group of the current generating units at the parallel connection point respectively, for controlling the voltage of the parallel connection point to be equal to the voltage of the second end of the first MOS tube.

[0014] Optionally, the clamping circuit comprises:

[0015] A transistor, electrically connected to the second end of each of the first MOS tubes;

[0016] A first operational amplifier, wherein a first input terminal of the first operational amplifier is electrically connected to each group of the current generating units at the parallel connection point, a second input terminal of the first operational amplifier is electrically connected to the transistor and the second terminal of each of the first MOS tubes, and an output terminal of the first operational amplifier is electrically connected to the transistor.

[0017] Optionally, the transistor is a second MOS transistor;

[0018] The second MOS tube includes a second gate, a third end and a fourth end. The second gate of the second MOS tube is electrically connected to the output end of the first operational amplifier. The third end of the second MOS tube is electrically connected to the second input end of the first operational amplifier and the second end of the first MOS tube respectively. The fourth end of the second MOS tube is electrically connected to the first resistor.

[0019] Optionally, the current generating unit includes at least one third MOS tube;

[0020] The third MOS tube includes a third gate, a fifth end and a sixth end. The third gate of the third MOS tube is electrically connected to the first gate of each of the first MOS tubes. The fifth end of the third MOS tube is configured to apply an external voltage. The sixth end of the third MOS tube is configured to be electrically connected to the battery at the parallel connection point.

[0021] Optionally, the current generating unit further includes at least one control switch;

[0022] At least one of the control switches corresponds to at least one of the third MOS tubes one by one. The control switch is electrically connected to the first gate of each of the first MOS tubes and the third gate of the corresponding third MOS tube, respectively, and is configured to input a switching signal, so as to control the corresponding third MOS tube to generate current in response to the switching signal.

[0023] Optionally, a preset ratio between each of the unit currents and the reference current is the same.

[0024] Optionally, the control circuit includes a second operational amplifier;

[0025] The first input terminal of the second operational amplifier is configured to input a reference voltage, the second input terminal of the second operational amplifier is electrically connected to a reference current generating circuit, and the output terminal of the second operational amplifier is respectively electrically connected to the reference current generating circuit and each group of the current generating units, for outputting a control signal in response to the reference voltage.

[0026] In a second aspect, an embodiment of the present invention provides a power supply device, comprising the power supply circuit as described above.

[0027] Compared with the prior art, an embodiment of the present invention provides a power supply circuit and a power supply device, wherein the power supply circuit includes a control circuit, a reference current generating circuit and a charging current generating circuit, wherein the control circuit is used to output a control signal, the reference current generating circuit is used to generate a reference current in response to the control signal, the charging current generating circuit includes a plurality of groups of current generating units, each group of current generating units is electrically connected to the reference current generating circuit and the control circuit, each group of current generating units is connected in parallel and is configured to be electrically connected to a battery at a parallel connection point, a target current generating unit generates a unit current in response to the control signal to output a target charging current at the parallel connection point to charge the battery, the unit current is in a preset ratio to the reference current, and the target charging current is the sum of the unit currents generated by the target current generating units. Therefore, this embodiment divides the charging current generating circuit for generating the charging current into a plurality of groups of current generating units, each group of current generating units is used to generate a unit current proportional to the reference current, and the charging current is composed of the generated unit currents. Compared with the traditional technology, the current ratio between the second transistor and the first transistor is equivalently reduced, so that the proportional deviation between the reference current and the charging current can be reduced, thereby improving the matching accuracy between the reference current and the charging current, ensuring that the actual charging current is basically consistent with the required charging current, which is beneficial to improving the accuracy of the charging current, improving the charging efficiency, and reducing the safety risks caused by overheating. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0029] Figure 1 A schematic diagram of an application environment of a power supply circuit provided by an embodiment of the present invention;

[0030] Figure 2 A schematic diagram of the structure of a power supply circuit provided by an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of the circuit structure of a power supply circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] It should be noted that, if there is no conflict, the various features in the embodiments of the present invention can be combined with each other, all within the scope of protection of the present invention. In addition, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in a different order from the module division in the device or the flow chart. Furthermore, the words "first", "second", "third", etc. used in the present invention do not limit the data and execution order, but only distinguish the same items or similar items with basically the same functions and effects.

[0034] See also Figure 1 , Figure 1 A schematic diagram of an application environment of a power supply circuit is provided for an embodiment of the present invention, such as Figure 1 As shown, the application environment includes a power supply circuit 100 and a battery 200. The power supply circuit 100 is electrically connected to the battery 200 and is configured to input an external power supply. The external power supply can be a DC power supply or an AC power supply. The power supply circuit 100 is used to output a charging voltage or current to the battery 200 after converting the external power supply, thereby charging the battery 200.

[0035] The battery 200 may be any type of rechargeable battery, including but not limited to a lithium-ion battery, a nickel-metal hydride battery, a nickel-cadmium battery, a lithium polymer battery, and the like.

[0036] In some embodiments, see Figure 2 The power supply circuit 100 includes a control circuit 10 , a reference current generating circuit 20 and a charging current generating circuit 30 .

[0037] The control circuit 10 is used to output a control signal, and the control signal is used to control the current generation of the reference current generating circuit 20 and the charging current generating circuit 30. The control signal may include any type of signal used to control the current generation of the reference current generating circuit 20 and the charging current generating circuit 30. In some embodiments, the control signal is a voltage signal.

[0038] The reference current generating circuit 20 is electrically connected to the control circuit 10 and is used to generate a reference current in response to a control signal. The reference current refers to a reference value or expected value used to set or adjust the charging current during the charging process, and is used to guide the power circuit 100 on how to charge the battery 200.

[0039] The charging current generating circuit 30 includes a plurality of groups of current generating units 31, each group of current generating units 31 is electrically connected to the reference current generating circuit 20 and the control circuit 10 respectively, each group of current generating units 31 is connected in parallel and is configured to be electrically connected to the battery 200 at a parallel connection point 30a, each group of current generating units 31 can generate a unit current in response to a control signal, and the unit current generated by each group of current generating units 31 is in a preset ratio with the reference current, and the preset ratio can be set according to actual needs. For example, assuming that the reference current is ISET, the ratio of the unit current IBU generated by the current generating unit 31 to the reference current is K, then the unit current IBU generated by the current generating unit 31 is K*ISET.

[0040] The charging current generating circuit 30 is a power module of the power supply circuit 100. Compared with the traditional technology, the charging current generating circuit 30 is composed of multiple groups of current generating units 31 to generate the charging current, which is equivalent to splitting the power module into multiple power units, and equivalently reducing the current ratio between the second transistor and the first transistor, thereby reducing the ratio deviation between the reference current and the charging current.

[0041] Each group of current generating units 31 can be turned on or off according to actual needs. For example, the charging current generating circuit 30 includes 64 groups of current generating units 31. In actual applications, one or more of the current generating units 31 can be turned on, such as 1 group, 10 groups, 32 groups, 64 groups, etc. The turned-on current generating unit 31 can generate a unit current, and the turned-off current generating unit 31 does not generate a unit current.

[0042] The target current generating unit generates a unit current in response to the control signal to output a target charging current at the parallel connection point 30a to charge the battery 200. The target current generating unit is the current generating unit 31 turned on in the charging current generating circuit 30. Assuming that the target current generating unit includes 32 groups of current generating units 31, and the unit current generated by each group of current generating units 31 is IBU, the target charging current IBAT=32*IBU.

[0043] It is understandable that in practical applications, the unit current size of each current generating unit 31 can be determined according to the maximum charging current, and then the target current generating unit can be determined according to the target charging current, and finally the reference current generated by the reference current generating circuit 20 can be adjusted to output the target charging current at the parallel connection point 30a to charge the battery 200. For example, the maximum charging current is 960mA, the charging current generating circuit 30 includes 64 groups of current generating units 31, and the unit current IBU generated by each group of current generating units 31 is the same, then the unit current IBU=960 / 64=15mA, assuming that the target charging current is 480mA, then only 32 groups of current generating units 31 need to be turned on as target current generating units, and if the ratio of the unit current 15mA to the reference current is K, then only the reference current ISET=15mA / K needs to be set to meet the charging demand.

[0044] Therefore, in this embodiment, the charging current generating circuit 30 for generating the charging current is divided into a plurality of groups of current generating units 31, each group of current generating units 31 is used to generate a unit current proportional to the reference current, and the charging current is composed of the generated unit currents. Compared with the traditional technology, the current ratio between the second transistor and the first transistor is equivalently reduced, so that the proportional deviation between the reference current and the charging current can be reduced, thereby improving the matching accuracy between the reference current and the charging current, ensuring that the actual charging current is basically consistent with the required charging current, which is beneficial to improve the accuracy of the charging current, improve the charging efficiency, and reduce the safety risks caused by overheating.

[0045] It is understandable that in actual applications, in different occasions, different batteries 200, and when the battery temperature or other factors change during charging, the charging current span of the battery 200 is very large, and the working current of the second transistor changes from a minimum of more than ten milliamperes to the maximum current allowed by the chip constant current charging. With different charging currents, the working area of ​​the second transistor may be different states such as subthreshold working area, saturation working area, resistance working area, deep resistance working area, etc. With the difference in the working state of the first transistor and the second transistor, the current ratio of the first transistor to the second transistor will also deviate from the design value, and the charging current will change with the different working states of the power tube, which poses a challenge to the safety and timeliness of battery charging, and will affect the customer experience or cause risks on the application end.

[0046] In some embodiments, the preset ratio between each unit current and the reference current is the same. Since the ratio between each unit current and the reference current is the same, the working state of each current generating unit 31 after being turned on is the same. Compared with the conventional technology, this embodiment can avoid the problem that the ratio between the reference current and the charging current deviates from the design value, thereby further improving the matching accuracy between the reference current and the charging current, which is conducive to further improving the accuracy of the charging current.

[0047] It can be understood that during the process of the power supply circuit 100 charging the battery 200, since each group of current generating units 31 can operate within its maximum driving capability range, when the target current generating unit drives the target charging current, the maximum driving capability of each group of current generating units 31 can be exerted, thereby avoiding the situation of insufficient current driving capability and making better use of the current driving capability.

[0048] In some embodiments, see Figure 3 , the reference current generating circuit 20 includes at least one first MOS tube Q1 and a first resistor R1.

[0049] Each first MOS transistor Q1 includes a first gate, a first end, and a second end. The first gate of each first MOS transistor Q1 is electrically connected to the control circuit 10 and each group of current generating units 31, respectively. The first end of each first MOS transistor Q1 is configured to input an external voltage VDD. The second end of each first MOS transistor Q1 is electrically connected to one end of the first resistor R1, and the other end of the first resistor R1 is grounded.

[0050] In the present embodiment, at least one first MOS transistor Q1, the first resistor R1 and the control circuit 10 may form a current loop, and the current of the circuit loop, i.e., the reference current, may be adjusted by adjusting the control signal, the size of the at least one first MOS transistor Q1 or the resistance value of the first resistor R1, for example, by adjusting the control signal alone, or by controlling the size of the at least one first MOS transistor Q1 alone, or by adjusting the resistance value of the first resistor R1 alone, or by adjusting the control signal and the size of the at least one first MOS transistor Q1 at the same time, or by adjusting the control signal and the resistance value of the first resistor R1 at the same time, or by adjusting the size of the at least one first MOS transistor Q1 and the resistance value of the first resistor R1 at the same time, or by adjusting the control signal, the size of the at least one first MOS transistor Q1 and the resistance value of the first resistor R1 at the same time.

[0051] It can be understood that when the number of the first MOS tubes Q1 is more than one, the first MOS tubes Q1 are connected in parallel, and the size of at least one first MOS tube Q1 is the sum of the sizes of the first MOS tubes Q1 connected in parallel. Therefore, when adjusting the size of more than one first MOS tube Q1, the size of only one of the first MOS tubes Q1 can be adjusted, or the sizes of multiple first MOS tubes Q1 can be adjusted at the same time, or the size of each first MOS tube Q1 can be adjusted at the same time. Of course, in some other embodiments, the size can also be adjusted by controlling the number of first MOS tubes Q1 that are turned on. For example, the number of at least one first MOS tube Q1 is 3, and at this time, two of the first MOS tubes Q1 can be controlled to be turned on, and the other first MOS tube Q1 can be turned off.

[0052] The first MOS transistor Q1 may be an NMOS transistor or a PMOS transistor. Of course, in some other embodiments, the first MOS transistor Q1 may also be replaced by other types of transistors such as IGBT (Insulate-Gate Bipolar Transistor).

[0053] It is understandable that if the first MOS transistor Q1 is an NMOS transistor, Figure 3 As shown, the first end of the first MOS tube Q1 is the source of the NMOS tube, and the second end of the first MOS tube Q1 is the drain of the NMOS tube, that is, the source of the NMOS tube is configured to input the external voltage VDD, and the drain of the NMOS tube is electrically connected to one end of the first resistor R1. If the first MOS tube Q1 is a PMOS tube, the first end of the first MOS tube Q1 is the drain of the PMOS tube, and the second end of the first MOS tube Q1 is the source of the PMOS tube, that is, the drain of the PMOS tube is configured to input the external voltage VDD, and the source of the PMOS tube is electrically connected to one end of the first resistor R1.

[0054] In some embodiments, Figure 3 As shown, the control circuit 10 includes a second operational amplifier EA2.

[0055] The first input terminal of the second operational amplifier EA2 is configured to input the reference voltage VREF, the second input terminal of the second operational amplifier EA2 is electrically connected to the reference current generating circuit 20, and the output terminal of the second operational amplifier EA2 is respectively electrically connected to the reference current generating circuit 20 and each group of current generating units 31, for outputting a control signal in response to the reference voltage VREF.

[0056] In this embodiment, the control signal output by the second operational amplifier EA2 can change with the change of the reference voltage VREF. Therefore, by adjusting the reference voltage VREF, the control signal can be adjusted, thereby adjusting the reference current. The reference voltage VREF can be set according to actual needs, and the specific value is not limited here.

[0057] The first input terminal of the second operational amplifier EA2 may be a non-inverting input terminal or an inverting input terminal, and the second input terminal of the second operational amplifier EA2 may be a non-inverting input terminal or an inverting input terminal.

[0058] It can be understood that if the first input terminal of the second operational amplifier EA2 is the non-inverting input terminal, the second input terminal of the second operational amplifier EA2 is the inverting input terminal. At this time, the non-inverting input terminal of the second operational amplifier EA2 is configured as the input reference voltage VREF, and the inverting input terminal of the second operational amplifier EA2 is electrically connected to the reference current generating circuit 20.

[0059] It can also be understood that if the first input terminal of the second operational amplifier EA2 is the inverting input terminal, the second input terminal of the second operational amplifier EA2 is the non-inverting input terminal. At this time, the inverting input terminal of the second operational amplifier EA2 is configured as the input reference voltage VREF, and the non-inverting input terminal of the second operational amplifier EA2 is electrically connected to the reference current generating circuit 20.

[0060] In some embodiments, see Figure 3 The power supply circuit 100 further includes a clamping circuit 40 .

[0061] The clamp circuit 40 is electrically connected to the second end of the first MOS transistor Q1 and the first resistor R1 respectively, and is electrically connected to each group of current generating units 31 at the parallel connection point 30a respectively, for controlling the voltage of the parallel connection point 30a to be equal to the voltage of the second end of the first MOS transistor Q1.

[0062] In this embodiment, by clamping the voltage of the parallel connection point 30a and the voltage of the second end of the first MOS tube Q1 to the same potential, the matching relationship between the reference current and each unit current can be better satisfied, which is beneficial to further improve the matching accuracy between the reference current and the charging current, thereby facilitating improving the accuracy of the charging current.

[0063] In some embodiments, please refer to Figure 3 , the clamp circuit 40 includes a transistor 41 and a first operational amplifier EA1.

[0064] The transistor 41 is electrically connected to the second end of the first MOS transistor Q1 , the second input end and the output end of the first operational amplifier EA1 , respectively. The first input end of the first operational amplifier EA1 is electrically connected to each group of current generating units 31 at the parallel connection point 30 a .

[0065] In this embodiment, the first operational amplifier EA1 outputs a feedback signal to the transistor 41 in response to the second terminal voltage of the first MOS transistor Q1 and the voltage of the parallel connection point 30a. The transistor 41 adjusts its own working state in response to the feedback signal, thereby adjusting the second terminal voltage of the first MOS transistor Q1 and the voltage of the parallel connection point 30a to the same potential.

[0066] The first input terminal of the first operational amplifier EA1 may be a non-inverting input terminal or an inverting input terminal, and the second input terminal of the first operational amplifier EA1 may be a non-inverting input terminal or an inverting input terminal.

[0067] It can be understood that if the first input terminal of the first operational amplifier EA1 is the non-inverting input terminal, the second input terminal of the first operational amplifier EA1 is the inverting input terminal. At this time, the non-inverting input terminal of the first operational amplifier EA1 is electrically connected to each group of current generating units 31 at the parallel connection point 30a, and the inverting input terminal of the first operational amplifier EA1 is electrically connected to the transistor 41, the second end of the first MOS tube Q1 and the output terminal of the first operational amplifier EA1.

[0068] It can also be understood that if the first input terminal of the first operational amplifier EA1 is the inverting input terminal, the second input terminal of the first operational amplifier EA1 is the non-inverting input terminal. At this time, the inverting input terminal of the first operational amplifier EA1 is electrically connected to each group of current generating units 31 at the parallel connection point 30a, and the non-inverting input terminal of the first operational amplifier EA1 is electrically connected to the transistor 41, the second end of the first MOS tube Q1 and the output terminal of the first operational amplifier EA1.

[0069] The transistor 41 may include any suitable type of transistor, including but not limited to a MOS transistor (NMOS transistor or PMOS transistor), a BJT (Bipolar Junction Transistor), an IGBT, and the like.

[0070] In some embodiments, Figure 3 As shown, the transistor 41 is a second MOS transistor Q2.

[0071] The second MOS tube Q2 includes a second gate, a third end and a fourth end. The second gate of the second MOS tube Q2 is electrically connected to the output end of the first operational amplifier EA1. The third end of the second MOS tube Q2 is electrically connected to the second input end of the first operational amplifier EA1 and the second end of the first MOS tube Q1 respectively. The fourth end of the second MOS tube Q2 is electrically connected to the first resistor R1.

[0072] The second MOS transistor Q2 may be an NMOS transistor or a PMOS transistor. Of course, in some other embodiments, the second MOS transistor Q2 may also be replaced by other types of transistors such as IGBT (Insulate-Gate Bipolar Transistor).

[0073] It can be understood that if the second MOS transistor Q2 is an NMOS transistor, Figure 3 As shown, the third end of the second MOS tube Q2 is the source of the NMOS tube, and the fourth end of the second MOS tube Q2 is the drain of the NMOS tube, that is, the source of the NMOS tube is electrically connected to the second input end of the first operational amplifier EA1 and the second end of the first MOS tube Q1, respectively, and the drain of the NMOS tube is electrically connected to one end of the first resistor R. If the second MOS tube Q2 is a PMOS tube, the third end of the second MOS tube Q2 is the drain of the PMOS tube, and the fourth end of the second MOS tube Q2 is the source of the PMOS tube, that is, the drain of the PMOS tube is electrically connected to the second input end of the first operational amplifier EA1 and the second end of the first MOS tube Q1, respectively, and the source of the PMOS tube is electrically connected to one end of the first resistor R.

[0074] In some embodiments, Figure 3 As shown, the current generating unit 31 includes at least one third MOS tube Q3.

[0075] The third MOS transistor Q3 includes a third gate, a fifth end and a sixth end. The third gate of the third MOS transistor Q3 is electrically connected to the first gate of the first MOS transistor Q1. The fifth end of the third MOS transistor Q3 is configured to apply an external voltage VDD. The sixth end of the third MOS transistor Q3 is configured to be electrically connected to the battery 200 at the parallel connection point 30a.

[0076] In this embodiment, the current generating unit 31 includes one or more third MOS transistors Q3 , and the preset ratio of the unit current generated by the current generating unit 31 to the reference current is the ratio of the sum of the sizes of the third MOS transistors Q3 to the sum of the sizes of the first MOS transistors Q1 .

[0077] For example, when the current generating unit 31 includes a third MOS tube Q3 and at least one first MOS tube Q1, the size of the third MOS tube Q3 is in a preset ratio with the size of the first MOS tube Q1, so that the unit current generated by the current generating unit 31 is in a preset ratio with the reference current.

[0078] For another example, when the current generating unit 31 includes more than one third MOS tube Q3 and the number of at least one first MOS tube Q1 is 1, the sum of the sizes of the more than one third MOS tube Q3 is in a preset ratio to the size of the first MOS tube Q1, so that the unit current generated by the current generating unit 31 is in a preset ratio to the reference current.

[0079] For another example, when the current generating unit 31 includes a third MOS tube Q3 and at least one first MOS tube Q1, the size of the third MOS tube Q3 is in a preset ratio to the sum of the sizes of the more than one first MOS tubes Q1, so that the unit current generated by the current generating unit 31 is in a preset ratio to the reference current.

[0080] For another example, when the current generating unit 31 includes more than one third MOS tube Q3 and at least one first MOS tube Q1, the sum of the sizes of the more than one third MOS tube Q3 is in a preset ratio to the sum of the sizes of the more than one first MOS tube Q1, so that the unit current generated by the current generating unit 31 is in a preset ratio to the reference current.

[0081] It can also be understood that in the related art, the proportional relationship between the charging current and the reference current is achieved through a current mirror structure. Based on this current mirror structure, the power module used to generate the charging current can mirror the reference current and set the proportional relationship between the charging current and the reference current by adjusting the parameters of the current mirror structure. However, this current mirror structure will have the problem that the charging current and the reference current cannot be accurately matched, thereby reducing the accuracy of the charging current.

[0082] In this embodiment, although the sum of the sizes of at least one third MOS transistor Q3 and the sum of the sizes of at least one first MOS transistor Q1 are in a preset ratio, so that the unit current generated by the current generating unit 31 is in a preset ratio with the reference current, Figure 3 As shown, at least one third MOS tube Q3 and at least one first MOS tube Q1 do not form a current mirror structure. This non-current mirror structure is conducive to better meeting the matching accuracy between the charging current and the reference current, thereby facilitating improving the accuracy of the charging current.

[0083] As mentioned above, each group of current generating units 31 can exert its maximum driving capability. At this time, the over-driving voltage of the power tube (third MOS tube Q3) in each group of current generating units 31 reaches the maximum, and the matching accuracy between at least one third MOS tube Q3 and at least one first MOS tube Q1 is the highest, and it is easier to meet the requirement of precision matching between the reference current and the charging current, which is conducive to improving the accuracy of the charging current. In addition, this embodiment can greatly reduce the layout matching requirements between at least one third MOS tube Q3 and at least one first MOS tube Q1, thereby reducing the requirements for the back-end layout design, which is conducive to simplifying the layout design, reducing the layout complexity, reducing the layout area, and saving space.

[0084] It can be understood that, under the same CV (Constant Voltage) current, the larger the size of the power tube, the closer its working area is to the subthreshold working area, and the deeper the subthreshold working area, the greater the matching deviation between the power tube and the at least one first MOS tube Q1, thereby seriously affecting the matching accuracy between the reference current and the charging current. In this embodiment, by splitting the large-size power tube into multiple groups of small-size power tubes, it is beneficial to ensure that each group of small-size power tubes can work in a deep saturation region or a state close to the saturation region, thereby facilitating the improvement of the matching accuracy between the power tube as a whole and the at least one first MOS tube Q1, thereby achieving a good current matching effect. Since the power tube for generating the charging current includes multiple groups of small-size power tubes, each group of small-size power tubes can be selected according to the required charging current, so that the size ratio between the power tube and the at least one first MOS tube Q1 can be adjusted to a smaller range, so that it can be ensured that the power tube will not work in the deep subthreshold working area, and even when the battery 200 is in CV cutoff, the matching accuracy between the power tube and the at least one first MOS tube Q1 can be ensured.

[0085] According to actual measurements, when the CV cut-off current is 1mA, the CC current is 60mA. In actual tests, the cut-off current deviation of 1mA can be within ±15%, thereby effectively improving the accuracy of the CV charging cut-off current.

[0086] In some embodiments, Figure 3 As shown, the current generating unit 31 further includes at least one control switch TG.

[0087] The at least one control switch TG may be one or more control switches TG, and the at least one control switch TG corresponds to the at least one third MOS tube Q3 on a one-to-one basis. The control switch TG is respectively electrically connected to the first gate of each first MOS tube Q1 and the third gate of the corresponding third MOS tube Q3, and is configured to input a switching signal, and is used to control the corresponding third MOS tube Q3 to generate current in response to the switching signal.

[0088] For example, assuming that in a set of current generating units 31, the number of control switches TG is 1, and the number of third MOS transistors Q3 is also 1, then the control switch TG corresponds to the third MOS transistor Q3, that is, the control switch TG is electrically connected to the first gate of each first MOS transistor Q1 and the third gate of the third MOS transistor Q3 respectively. When the set of current generating units 31 is required to generate a unit current, the control switch TG can respond to a switch signal to be in a conducting state to control the third MOS transistor Q3 to generate a unit current. When the set of current generating units 31 is not required to generate a unit current, the control switch TG can respond to a switch signal to be in a disconnected state to control the third MOS transistor Q3 to be turned off. At this time, the third MOS transistor Q3 does not generate a unit current.

[0089] For another example, assuming that in a set of current generating units 31, the number of control switches TG is 2, namely, control switch TG1 and control switch TG2, the number of third MOS transistors Q3 is also 2, namely, third MOS transistor Q3_1 and third MOS transistor Q3_2, the control switch TG1 corresponds to the third MOS transistor Q3_1, and the control switch TG2 corresponds to the third MOS transistor Q3_2, that is, the control switch TG2 is electrically connected to the first gate of each first MOS transistor Q1 and the third gate of the third MOS transistor Q3_2, respectively, the control switch TG1 and the control switch TG2 can be configured with the same switch signal, and when the set of current generating units 31 is required to generate a unit current, the control switch TG1 is connected to the first gate of each first MOS transistor Q1 and the third gate of the third MOS transistor Q3_2. The switch TG1 can be in a conducting state in response to the switch signal to control the third MOS transistor Q3_1 to generate current, and the control switch TG2 can be in a conducting state in response to the switch signal to control the third MOS transistor Q3_2 to generate current, thereby forming a unit current, and the unit current is the sum of the currents generated by the third MOS transistor Q3_1 and the third MOS transistor Q3_2. When the group of current generating units 31 is not required to generate the unit current, the control switch TG1 can be in a disconnected state in response to the switch signal to control the third MOS transistor Q3_1 to turn off, and the control switch TG2 can be in a disconnected state in response to the switch signal to control the third MOS transistor Q3_2 to turn off, and at this time, the group of current generating units 31 does not generate the unit current.

[0090] It can be understood that, since a large current needs to flow through the source and drain of the third MOS tube Q3 when the current generating unit 31 is required to generate a unit current, by arranging at least one control switch TG between the first gate of each first MOS tube Q1 and the third gate of the corresponding third MOS tube Q3, on the one hand, the first MOS tube Q1 can be controlled to generate a current by controlling the first gate voltage of the first MOS tube Q1, and on the other hand, such an arrangement will not affect the current flowing through the source and drain of the third MOS tube Q3.

[0091] It can also be understood that the control switch TG may include any type of electronic switch tube for controlling the first gate voltage of the first MOS tube Q1, such as a MOS tube (NMOS tube or PMOS tube), BJT (Bipolar Junction Transistor), IGBT, etc.

[0092] As another aspect of the present invention, the present invention provides a power supply device, which includes the power supply circuit as described above. The power supply device can be any type of electronic device, including but not limited to a charger, a charger, etc.

[0093] Finally, it should be noted that the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments are not intended to be additional limitations on the content of the present invention. The purpose of providing these implementations is to make the understanding of the disclosure of the present invention more thorough and comprehensive. And under the idea of ​​the present invention, the above-mentioned technical features continue to be combined with each other, and there are many other changes in different aspects of the present invention as described above, which are all considered to be within the scope of the present invention. Further, for those of ordinary skill in the art, improvements or changes can be made according to the above description, and all these improvements and changes should belong to the scope of protection of the claims attached to the present invention.

Claims

1. A power supply circuit, characterized in that: include: A control circuit, used for outputting a control signal; A reference current generating circuit, electrically connected to the control circuit, for generating a reference current in response to the control signal; A charging current generating circuit comprises a plurality of groups of current generating units, each group of the current generating units being electrically connected to the reference current generating circuit and the control circuit respectively, each group of the current generating units being connected in parallel and being configured to be electrically connected to a battery at the parallel connection point, a target current generating unit generating a unit current in response to the control signal to output a target charging current at the parallel connection point to charge the battery, the unit current being in a preset ratio to the reference current, and the target charging current being the sum of the unit currents generated by the target current generating units.

2. The power supply circuit according to claim 1, characterized in that: The reference current generating circuit comprises: At least one first MOS transistor, each of the first MOS transistors comprises a first gate, a first end and a second end, the first gate of each of the first MOS transistors is electrically connected to the control circuit and each group of the current generating units respectively, and the first end of each of the first MOS transistors is configured to input an external voltage; A first resistor, one end of which is electrically connected to the second end of each of the first MOS transistors, and the other end of which is grounded.

3. The power supply circuit according to claim 2, characterized in that: The power supply circuit also includes a clamping circuit; The clamping circuit is electrically connected to the second end of each of the first MOS tubes and the first resistor, respectively, and is electrically connected to each group of the current generating units at the parallel connection point, respectively, for controlling the voltage at the parallel connection point to be equal to the voltage at the second end of each of the first MOS tubes.

4. The power supply circuit according to claim 3, characterized in that: The clamping circuit comprises: A transistor, electrically connected to the second end of each of the first MOS tubes; A first operational amplifier, wherein a first input terminal of the first operational amplifier is electrically connected to each group of the current generating units at the parallel connection point, a second input terminal of the first operational amplifier is electrically connected to the transistor and the second terminal of each of the first MOS tubes, and an output terminal of the first operational amplifier is electrically connected to the transistor.

5. The power supply circuit according to claim 4, characterized in that: The transistor is a second MOS tube; The second MOS tube includes a second gate, a third end and a fourth end. The second gate of the second MOS tube is electrically connected to the output end of the first operational amplifier. The third end of the second MOS tube is respectively electrically connected to the second input end of the first operational amplifier and the second end of each of the first MOS tubes. The fourth end of the second MOS tube is electrically connected to the first resistor.

6. The power supply circuit according to claim 2, characterized in that: The current generating unit includes at least one third MOS tube; The third MOS tube includes a third gate, a fifth end and a sixth end. The third gate of the third MOS tube is electrically connected to the first gate of each of the first MOS tubes. The fifth end of the third MOS tube is configured to apply an external voltage. The sixth end of the third MOS tube is configured to be electrically connected to the battery at the parallel connection point.

7. The power supply circuit according to claim 6, characterized in that: The current generating unit further comprises at least one control switch; At least one of the control switches corresponds to at least one of the third MOS tubes one by one. The control switch is electrically connected to the first gate of each of the first MOS tubes and the third gate of the corresponding third MOS tube, respectively, and is configured to input a switching signal, so as to control the corresponding third MOS tube to generate current in response to the switching signal.

8. The power supply circuit according to claim 6, characterized in that: The preset ratio between each of the unit currents and the reference current is the same.

9. The power supply circuit according to any one of claims 1 to 8, characterized in that: The control circuit includes a second operational amplifier; The first input terminal of the second operational amplifier is configured to input a reference voltage, the second input terminal of the second operational amplifier is electrically connected to a reference current generating circuit, and the output terminal of the second operational amplifier is respectively electrically connected to the reference current generating circuit and each group of the current generating units, for outputting a control signal in response to the reference voltage.

10. A power supply device, comprising the power supply circuit according to any one of claims 1 to 9.

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