Buck-boost control circuit compatible with battery charging and discharging functions

Abstract

A buck-boost control circuit compatible with a battery charging and discharging function comprises a direct-current power supply, a main control chip unit, a buck control unit and a boost control unit, when the output voltage of the direct-current power supply is higher than the input voltage of a system, a first buck output end of the main control chip unit outputs a switching signal, and a linear voltage is output through a third MOS tube; vOUT output voltage is generated to supply power to the system; when the output voltage of the direct-current power supply is lower than the input voltage of the system, the first boost output end of the main control chip unit outputs a switching signal, a linear voltage is output through a third MOS tube, and a VOUT output voltage is generated to supply power to the system; when the electric quantity of the battery is lower than 100% and the direct-current power supply supplies power, VOUT output supplies power to the system; when the direct-current power supply input end has no direct-current power supply, the battery directly supplies power to the system; one main control chip unit is adopted to respectively control the direct current power supply or the battery to supply power to the system, power supply is rapidly switched, normal work of the system is maintained, the structure is simple, maintenance is convenient, BOM materials are saved, and cost is reduced.

Description

Technical Field

[0001] The utility model relates to a rechargeable battery, in particular to a step-up and step-down control circuit compatible with battery charging and discharging functions. Background Art

[0002] With the rapid development of computer technology, computer performance is constantly improving, and its additional functions are also constantly being improved to meet the current computer application needs of various industries.

[0003] In the prior art, for example, computer products for military applications have some special application requirements in terms of their functions, and need to be compatible with wide voltage input and battery charging power supply functions to meet special requirements such as mobile applications.

[0004] At present, the existing technical solution must use two power chip circuits to be implemented: a wide voltage chip and a Charge charging chip. The wide voltage chip circuit is responsible for step-up and step-down conversion, and outputs a fixed voltage to provide input power for the system. The Charge charging chip circuit is responsible for charging the battery. When the motherboard is disconnected from the power supply, it switches to the battery to provide input power for the system.

[0005] The circuit using two chips is complex, the BOM materials are numerous, the product development and material costs are high, and there is no market competitive advantage. Utility Model Content

[0006] The purpose of the utility model is to overcome the deficiencies of the above-mentioned prior art and to provide a buck-boost control circuit that is compatible with battery charging and discharging functions. The utility model adopts a main control chip unit to control the DC power supply or the battery to power the system respectively, quickly switch the power supply, and maintain the normal operation of the system. The circuit structure is simple and easy to maintain, which saves BOM materials and reduces costs.

[0007] The utility model is implemented as follows: a buck-boost control circuit compatible with battery charging and discharging functions, used for adjusting the VOUT output voltage input to the system, comprising:

[0008] A DC power supply, used for outputting a DC voltage;

[0009] A main control chip unit, used to be connected to the DC power supply, when the DC voltage output by the DC power supply is higher than the voltage of the system power supply, the main control chip unit is in a step-down state and outputs a step-down instruction, when the DC voltage output by the DC power supply is lower than the voltage of the system power supply, the main control chip unit is in a step-up state and outputs a step-up instruction;

[0010] A step-down control unit, which is used to reduce the DC voltage output by the DC power supply according to the step-down instruction output by the main control chip unit, and the step-down control unit includes a first MOS tube and a second MOS tube, the drain of the first MOS tube is connected to the input end of the DC power supply, the gate of the first MOS tube is connected to the first step-down control end of the main control chip unit, the source of the first MOS tube is respectively connected to the first step-down output end of the main control chip unit and the drain of the second MOS tube, the gate of the second MOS tube is connected to the second step-down control end of the main control chip unit, and the source of the first MOS tube is connected to the second step-down output end of the main control chip unit;

[0011] a boost control unit, which is used to boost the DC voltage output by the DC power supply according to the boost instruction output by the main control chip unit, wherein the boost control unit includes a third MOS tube and a fourth MOS tube, wherein the drain of the third MOS tube is used to be directly or indirectly connected to the system, the gate of the third MOS tube is connected to the first boost control terminal of the main control chip unit, the source of the third MOS tube is respectively connected to the first boost output terminal of the main control chip unit, the source of the first MOS tube, the drain of the second MOS tube and the drain of the fourth MOS tube, the gate of the fourth MOS tube is connected to the second boost control terminal of the main control chip unit, and the source of the fourth MOS tube is respectively connected to the second boost output terminal of the main control chip unit and the source of the second MOS tube;

[0012] A battery charge and discharge control unit, when the battery power is lower than 100% and the DC power supply is provided, the VOUT output is used to power the system; when the DC power supply is not provided, the battery charge and discharge control unit controls the battery to power the system according to the battery power supply instruction output by the main control chip unit.

[0013] The utility model provides a buck-boost control circuit compatible with battery charging and discharging functions, which adjusts the voltage input to the system, and comprises a DC power supply, a main control chip unit, a buck control unit and a boost control unit. When the DC power supply output voltage is higher than the system input voltage, the first buck output terminal of the main control chip unit outputs a switch signal, outputs a linear voltage through a third MOS tube, and generates a VOUT output voltage to power the system; when the DC power supply output voltage is lower than the system input voltage, the first boost output terminal of the main control chip unit outputs a switch signal, outputs a linear voltage through the third MOS tube, and generates a VOUT output voltage to power the system; when the battery power is lower than 100% and the DC power supply has a DC power supply, the VOUT output is used to power the system; when there is no DC power supply at the DC power supply input terminal, the battery directly powers the system; one main control chip unit can be used to control the DC power supply or the battery to power the system, and the power supply can be quickly switched to maintain the normal operation of the system. The circuit structure is simple and easy to maintain, which saves BOM materials and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solution of the present utility model, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 It is a block diagram of a buck-boost control circuit compatible with battery charging and discharging functions provided by an embodiment of the utility model.

[0016] Figure 2 It is the left half circuit diagram of a buck-boost control circuit compatible with battery charging and discharging functions provided by an embodiment of the utility model.

[0017] Figure 3 It is the right half circuit diagram of a buck-boost control circuit compatible with battery charging and discharging functions provided by an embodiment of the utility model.

[0018] Figure 4 It is a circuit diagram of an EC chip in a buck-boost control circuit compatible with battery charging and discharging functions provided by an embodiment of the utility model.

[0019] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0020] In the present invention, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or state relationships based on the positions or state relationships shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific position, or to be constructed and operated in a specific position.

[0021] In addition, some of the above terms may be used to express other meanings in addition to indicating a position or state relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in this utility model can be understood according to specific circumstances.

[0022] In addition, the terms "installed", "set", "provided with", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0023] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components, which may be the same or different in specific types and configurations, and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0025] Overview of Buck-Boost Control Circuit as an Example

[0026] like Figure 1 to Figure 3 As shown, an embodiment of the utility model provides a buck-boost control circuit compatible with battery charging and discharging functions, which is used to adjust the voltage input to the system, including:

[0027] A DC power supply (VIN) for outputting a DC voltage;

[0028] A main control chip unit (UP1) is used to be connected to the DC power supply (VIN); when the DC voltage output by the DC power supply (VIN) is higher than the voltage of the system power supply, the main control chip unit (UP1) is in a step-down state and outputs a step-down instruction; when the DC voltage output by the DC power supply (VIN) is lower than the voltage of the system power supply, the main control chip unit (UP1) is in a step-up state and outputs a step-up instruction;

[0029] A step-down control unit (100) is used to reduce the DC voltage output by the DC power supply (VIN) according to the step-down instruction output by the main control chip unit (UP1), the step-down control unit (100) comprising a first MOS tube (QP1) and a second MOS tube (QP3), the drain (D) of the first MOS tube (QP1) being connected to the input end of the DC power supply (VIN), the gate (G) of the first MOS tube (QP1) being connected to the first step-down control end (i.e., the TG1 pin, used for outputting the gate drive control signal of the step-down MOS tube QP1) of the main control chip unit (UP1), and the first MOS tube (QP1) being connected to the input end of the DC power supply (VIN), and the gate (G) of the first MOS tube (QP1) being connected to the first step-down control end (i.e., the TG1 pin, used for outputting the gate drive control signal of the step-down MOS tube QP1) of the main control chip unit (UP1). The source electrode (S) of the first MOS tube (QP1) is respectively connected to the first step-down output terminal (i.e., the SW1 pin, used for outputting a step-down switch signal) of the main control chip unit (UP1) and the drain electrode (D) of the second MOS tube (QP3), the drain electrode (G) of the second MOS tube (QP3) is connected to the second step-down control terminal (i.e., the BG1 pin, used for outputting a step-down MOS tube QP3 gate drive control signal) of the main control chip unit (UP1), and the source electrode (S) of the first MOS tube (QP1) is connected to the second step-down output terminal (i.e., the SENSBOT pin, used for outputting a VOUT output current detection signal) of the main control chip unit (UP1);

[0030] A boost control unit (200) is used to boost the DC voltage output by the DC power supply (VIN) according to a boost instruction output by the main control chip unit (UP1), the boost control unit (200) comprising a third MOS tube (QP2) and a fourth MOS tube (QP4), the drain (D) of the third MOS tube (QP2) being used to be directly or indirectly connected to the system, the gate (G) of the third MOS tube (QP2) being connected to the first boost control end (i.e., the TG2 pin, used to output the boost MOS tube QP2 gate drive control signal) of the main control chip unit (UP1), the source (S) of the third MOS tube (QP2) being respectively connected to the first boost output end (i.e., the SW2 pin, used to output the boost switch signal) of the main control chip unit (UP1), the source (S) of the first MOS tube (QP1), the source (S) of the third MOS tube (QP4) and the drain (D) of the third MOS tube (QP2) being used to be directly or indirectly connected to the system, the gate (G) of the third MOS tube (QP2) being connected to the first boost control end (i.e., the TG2 pin, used to output the boost MOS tube QP2 gate drive control signal) of the main control chip unit (UP1), and the source (S) of the third MOS tube (QP2) being respectively connected to the first boost output end (i.e., the SW2 pin, used to output the boost switch signal) of the main control chip unit (UP1), the source (S) of the first MOS tube (QP1), the source (S) of the third MOS tube (QP4) and the drain (D) of the third MOS tube (QP2) being used to be directly or indirectly connected to the system, the gate (G) of the third MOS tube (QP2) being connected to the first boost control end (i.e., the TG2 pin, used to output the boost MOS tube QP2 gate drive control signal) of The drain (D) of the second MOS tube (QP3) is connected to the drain (D) of the fourth MOS tube (QP4), the gate (G) of the fourth MOS tube (QP4) is connected to the second boost control terminal (i.e., the BG2 pin, used for outputting the boost MOS tube QP4 gate drive control signal) of the main control chip unit (UP1), the source (S) of the fourth MOS tube (QP4) is respectively connected to the second boost output terminal (i.e., the SENSGND pin, the SENSBOT current detection reference ground) of the main control chip unit (UP1) and the source (S) of the second MOS tube (QP3), the two MOS tube sources are simultaneously connected to the SENSBOT current detection signal of UP1, and then grounded through the RP6 current limiting precision resistor, which has the function of limiting the maximum output current of VOUT, playing an OCP protection role, and preventing circuit components from being damaged.

[0031] When the output voltage of the DC power supply (VIN) is higher than the system input voltage, the main control chip unit (UP1) is in a step-down working state, the first step-down control end (TG1 pin outputs TG1 signal) and the second step-down control end (BG1 pin outputs BG1 signal) of the main control chip unit (UP1) respectively control the first MOS tube QP1 and the second MOS tube QP3 to perform switching operations, the third MOS tube QP2 operates in a linear state, and the fourth MOS tube QP4 stops working. The first step-down output end (SW1 pin outputs SW1 signal) outputs a switching signal, which is filtered by the inductor PL1 to output a stable voltage signal, and then outputs a linear voltage through the third MOS tube QP2. The voltage is input from the source S of the third MOS tube (QP2) to the drain D, and generates a VOUT output voltage to power the system.

[0032] When the output voltage of the DC power supply (VIN) is lower than the system input voltage, the main control chip unit (UP1) is in a boost working state, and the first boost control end (TG2 pin outputs TG2 signal) and the second boost control end (BG2 pin outputs BG2 signal) of the main control chip unit (UP1) respectively control the third MOS tube QP2 and the fourth MOS tube QP4 to perform switching operations, the first MOS tube QP1 operates in a linear state, the second MOS tube QP3 stops working, and then the first boost output end (SW2 pin outputs SW2 signal) outputs a switching signal, which is filtered by the inductor PL1 and outputs a stable voltage signal, and then passes through the third MOS tube QP2 to output a linear voltage (that is, the voltage output from the source S of QP2 to the drain D is a direct-pass mode), and finally, the source S of the third MOS tube QP2 is input to the drain D to generate a VOUT output voltage to power the system.

[0033] Preferably, the DC power supply (VIN) is respectively connected to the SHDN pin, the VIN_REG pin, the PVIN pin, the SENSVIN pin, the SENSTOP pin of the main control chip unit (UP1) and the drain (D) of the first MOS tube (QP1);

[0034] A first resistor (RP1) for voltage stabilization is connected between the DC power supply (VIN) and the drain (D) of the first MOS tube (QP1), the SENSVIN pin is connected to a node between the DC power supply (VIN) and the first resistor (RP1), and the SENSTOP pin is connected to a node between the DC power supply (VIN) and the drain (D) of the first MOS tube (QP1);

[0035] A coupling unit (300) is connected to a node between the DC power supply (VIN) and the first resistor (RP1), the coupling unit (300) comprising a plurality of first capacitors (CEP1 / CEP2 / CP1 / CP2 / CP3 / CP4) arranged in parallel, each of the first capacitors being grounded.

[0036] In this embodiment, the first resistor (RP1) is a precision resistor that can limit the input current. When the current exceeds the set current value, the main control chip unit (UP1) stops working to avoid damage. The first capacitors (CEP1 / CEP2 / CP1 / CP2 / CP3 / CP4) are all VIN input voltage filter capacitors to reduce interference and enhance the stability of the VIN voltage.

[0037] Overview of differential pressure regulating unit with built-in differential pressure as an example

[0038] like Figure 2As shown, further, the main control chip unit (UP1) also includes a pressure difference adjustment unit (400) for adjusting the built-in pressure difference of the first MOS tube (QP1), the second MOS tube (QP3), the third MOS tube (QP2) and the fourth MOS tube (QP4), and the pressure difference adjustment unit (400) includes the INTVCC pin of the main control chip unit (UP1) and a second capacitor (CP6) connected in parallel with the INTVCC pin, a first diode (D1), and a second diode (D2);

[0039] One end of the second capacitor (CP6), the anode of the first diode (D1) and the anode of the second diode (D2) are all connected to the INTVCC pin, the other end of the second capacitor (CP6) is grounded, the cathode of the first diode (D1) is connected to the node between the BST1 pin of the main control chip unit and the source (S) of the first MOS tube (QP1), and a third capacitor (CP11) for coupling is connected between the cathode of the first diode (D1) and the source (S) of the first MOS tube (QP1); the BST1 pin is powered by INTVCC (5V), and the chip TG1 signal is pressurized through internal chip control, thereby driving the MOS tube QP1 to turn on.

[0040] The cathode of the second diode (D2) is connected to the node between the BST2 pin of the main control chip unit and the source (S) of the third MOS tube (QP2), and a fourth capacitor (CP12) for coupling is connected between the cathode of the second diode (D2) and the source (S) of the first MOS tube (QP1). The BST2 pin is powered by INTVCC (5V), and the chip TG2 signal is pressurized through the internal control of the chip, thereby driving the MOS tube QP2 to conduct.

[0041] Overview of the First Undervoltage Protection Unit as an Example

[0042] like Figure 3 As shown, further, a first undervoltage protection unit (500) is arranged between the SHDN pin of the main control chip unit (UP1) and the DC power supply (VIN), and the first undervoltage protection unit (500) comprises a second resistor (RP2) and a third resistor (RP3) arranged in series, the second resistor (RP2) and the third resistor (RP3) are voltage divider resistors, wherein one end of the second resistor (RP2) is connected to the DC power supply (VIN), the other end of the second resistor (RP2) is connected to one end of the third resistor (RP3), the other end of the third resistor (RP3) is grounded, and the SHDN pin of the main control chip unit (UP1) is connected to the node between the second resistor (RP2) and the third resistor (RP3).

[0043] In this embodiment, the resistance values ​​of the second resistor (RP2) and the third resistor (RP3) are set according to requirements, and when the input voltage does not reach the set voltage value, the main control chip unit (UP1) does not work.

[0044] Overview of the Second Undervoltage Protection Unit as an Example

[0045] like Figure 3 As shown, further, a second undervoltage protection unit (600) is arranged between the VIN_REG pin of the main control chip unit (UP1) and the DC power supply (VIN), and the second undervoltage protection unit (600) includes a fourth resistor (RP4) and a fifth resistor (RP5) arranged in series, wherein one end of the fourth resistor (RP4) is connected to the DC power supply (VIN), the other end of the fourth resistor (RP4) is connected to one end of the fifth resistor (RP5), the other end of the fifth resistor (RP5) is grounded, and the VIN_REG pin of the main control chip unit (UP1) is connected to the node between the fourth resistor (RP4) and the fifth resistor (RP5).

[0046] like Figure 2 As shown, further, a sixth resistor (RP6) for voltage stabilization is connected to a node between the SENSGND pin of the main control chip unit (UP1) and the source (S) of the third MOS tube (QP3) and the source (S) of the fourth MOS tube (QP4).

[0047] Overview of the First Power Supply Protection Unit as an Example

[0048] like Figure 2 and Figure 4 As shown, further, a first power supply protection unit (700) is provided between the VFBMAX pin and the FBG pin of the main control chip unit (UP1) and the system, and the first power supply protection unit (700) comprises a seventh resistor (RP7), an eighth resistor (RP8) and a ninth resistor (RP15) connected in series in sequence;

[0049] The output end of the seventh resistor (RP7) is used to connect to the system, the input end of the ninth resistor (RP15) is used to connect to the FBG pin, and the VFBMAX pin is connected to the node between the eighth resistor (RP8) and the ninth resistor (RP15).

[0050] In this embodiment, regardless of whether it is in a buck or boost working state, the voltage value of the input system remains unchanged, the main control chip unit (UP1) can support a wide voltage input and output of 4.5V to 55V, and the output voltage can be changed by adjusting the resistance value of the seventh resistor (RP7), the eighth resistor (RP8) or the ninth resistor (RP15) as needed. The output voltage calculation method is: VOUT = VFBMAX (0.75V) * [1 + (RP7 + RP8) / RP15] The positive and negative electrodes of the battery (10) are connected to the PBCN1 interface to achieve connection with the battery charge and discharge control unit (120), wherein VFBMAX is the maximum feedback voltage.

[0051] Overview of the Second Power Supply Protection Unit as an Example

[0052] like Figure 3 As shown, further, a second power supply protection unit (800) is provided between the VFB pin and the FBG pin of the main control chip unit (UP1) and the system, and the second power supply protection unit (800) comprises a tenth resistor (RP11), an eleventh resistor (RP12) and a twelfth resistor (RP14) connected in series in sequence;

[0053] The output end of the tenth resistor (RP11) is used to be connected to the BAT pin of the main control chip unit (UP1), the input end of the twelfth resistor (RP14) is used to be connected to the FBG pin, and the VFB pin is connected to the node between the eleventh resistor (RP12) and the twelfth resistor (RP14).

[0054] In this example, by setting the resistance values ​​of the tenth resistor (RP11), the eleventh resistor (RP12) and the twelfth resistor (RP14), the maximum charging voltage of the battery (10) can be adjusted to prevent the battery (10) from being over-charged, thereby protecting the battery (10) from being damaged.

[0055] Overview of the third power supply protection unit as an example

[0056] like Figure 3 As shown, further, the NTC pin of the main control chip unit (UP1) is connected to a third power supply protection unit (900) for protecting the power supply voltage of the PVIN pin, and the third power supply protection unit is a thermistor (RP16) that changes with the operating temperature of the main control chip unit (UP1) and thereby changes the power supply voltage of the PVIN pin, and the thermistor (RP16) plays a role in protecting the main control chip unit (UP1) from being damaged.

[0057] Overview of the charging time limit unit as an example

[0058] like Figure 3As shown, further, the TIMER pin of the main control chip unit (UP1) is connected to a charging time limiting unit (900) for limiting the charging time of the battery (10), and the charging time limiting unit (110) is an MLCC capacitor (C10). The main control power chip can set an MLCC capacitor (C10) at the signal output end of the TIMER pin according to the battery charging demand, and the charging time of the battery (10) can be set by changing the capacitance of the MLCC capacitor (C10), thereby avoiding the phenomenon of long-term charging of the battery (10).

[0059] Overview of a battery charging and discharging control unit as an example

[0060] like Figure 2 As shown, further, a battery charge and discharge control unit (120) is included, and the battery charge and discharge control unit (120) includes:

[0061] a fifth MOS tube (QP5), a gate (G) of the fifth MOS tube (QP5) being connected to a first control end (i.e., a BGATE pin, used for outputting a QP5 gate level control signal to control the on and off of the MOS tube) of the main control chip unit (UP1), a source (S) of the fifth MOS tube (QP5) being connected to a system via a thirteenth resistor (RP10); a CSP pin of the main control chip unit (UP1) being connected to a node between the thirteenth resistor (RP10) and the system via a fourteenth resistor (RP9); a CSN pin of the main control chip unit (UP1) being connected to a node between the thirteenth resistor (RP10) and the system via a fifteenth resistor (RP13); The node between the resistor (RP10) and the source (S) of the fifth MOS tube (QP5) is connected; the drain (D) of the fifth MOS tube (QP5) is grounded through a fifth capacitor (CP13) for coupling; when the battery (10) is in a discharging state, the discharge voltage of the battery (10) passes through the fifth MOS tube (QP5) and the thirteenth resistor (RP10) to supply power to the system; in this embodiment, the thirteenth resistor (RP10) is a precision resistor, which is used to limit the charging current of the battery (10), prevent the battery (10) from being overcharged, and play a role in protecting the battery (10), wherein the resistors RP9 and RP13 play a role in signal isolation and reducing current detection interference.

[0062] A sixth MOS transistor (QP6), wherein the drain (D) of the sixth MOS transistor (QP6) is respectively connected to the node between the drain (D) of the fifth MOS transistor (QP5) and the fifth capacitor (CP13) and the second control terminal (i.e., the BAT pin, used for limiting the maximum battery charging voltage) of the main control chip unit (UP1), and the source (S) of the sixth MOS transistor (QP6) is directly or indirectly connected to the battery (10), and in this example, is connected to the battery via the first interface PBCN1.

[0063] A seventh MOS tube (QP7), wherein a gate electrode (G) of the seventh MOS tube (QP7) is connected to a power supply terminal (+3VSB) via a delay unit (121), a drain electrode (D) of the seventh MOS tube (QP7) is grounded, and a source electrode (S) of the seventh MOS tube (QP7) is connected to a drain electrode (G) of the sixth MOS tube (QP6), and is used to control the conduction or cutoff of the sixth MOS tube (QP6); when the battery (10) is in a charging state, a charging voltage supplied to the battery (10) charges the battery (10) via the sixth MOS tube (QP6).

[0064] Preferably, the delay unit (121) comprises a resistor (PR1) and a capacitor (C1) arranged in series, the input end of the resistor (PR1) is connected to the power supply end (+3VSB), the gate (G) of the seventh MOS transistor (QP7) is connected to the node between the resistor (PR1) and the capacitor (C1), and the capacitor (C1) is grounded.

[0065] When the charge of the battery (10) is lower than 100% and there is a DC power supply at the input end of the DC power supply VIN, the VOUT output provides working power for the system, and at the same time charges the battery (10) on the PBCN1 interface through the thirteenth resistor (RP10), the fifth MOS tube (QP5) and the sixth MOS tube (QP6); when the charge of the battery (10) reaches 100%, the VOUT voltage stops charging the battery (10), and VOUT only supplies power to the system.

[0066] When there is no DC power supply at the DC power supply VIN input end, the battery voltage on the PBCN1 interface reaches the VOUT output end through the sixth MOS tube (QP6), the fifth MOS tube QP5 and the thirteenth resistor (RP10), and the battery (10) directly powers the system. When the system fails due to an abnormality and loses power, the battery (10) can be quickly switched to continue to power the system, thereby preventing the system from shutting down due to abnormal power failure, thereby avoiding the phenomenon of system file damage and data loss. The circuit structure is simple and easy to maintain, saving BOM materials and reducing costs.

[0067] Overview of anti-static unit and filter unit as examples

[0068] like Figure 2As shown, further, an antistatic unit (130) and a filter unit (140) are arranged between the battery charge and discharge control unit (120) and the battery (10), the antistatic unit (130) is a diode (EOSB1), and the filter unit (140) is a first filter capacitor (CB1) and a second filter capacitor (CB2) arranged in parallel; wherein the positive electrode of the diode (EOSB1) is grounded, the negative electrode of the diode (EOSB1), one end of the first filter capacitor (CB1) and the second filter capacitor (CB2) are respectively connected to the output end of the battery charge and discharge control circuit, and the other ends of the first filter capacitor (CB1) and the second filter capacitor (CB2) are grounded.

[0069] In this example, the buck-boost control circuit compatible with the battery charging and discharging function also includes a voltage output unit 150 for stabilizing the voltage input to the system. The voltage output unit 150 is composed of a plurality of voltage stabilizing capacitors arranged in parallel.

[0070] like Figure 4 As shown, in this example, the buck-boost control circuit compatible with the battery charging and discharging functions also includes an EC control module U1 for monitoring the battery (10) power and working status.

[0071] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the protection scope of the present invention.

Claims

1. A buck-boost control circuit compatible with battery charging and discharging functions, used to adjust the VOUT output voltage input to the system, characterized in that: include: A DC power supply, used for outputting a DC voltage; A main control chip unit, used to be connected to the DC power supply, when the DC voltage output by the DC power supply is higher than the voltage of the system power supply, the main control chip unit is in a step-down state and outputs a step-down instruction, when the DC voltage output by the DC power supply is lower than the voltage of the system power supply, the main control chip unit is in a step-up state and outputs a step-up instruction; A step-down control unit, which is used to reduce the DC voltage output by the DC power supply according to the step-down instruction output by the main control chip unit, and the step-down control unit includes a first MOS tube and a second MOS tube, the drain of the first MOS tube is connected to the input end of the DC power supply, the gate of the first MOS tube is connected to the first step-down control end of the main control chip unit, the source of the first MOS tube is respectively connected to the first step-down output end of the main control chip unit and the drain of the second MOS tube, the gate of the second MOS tube is connected to the second step-down control end of the main control chip unit, and the source of the first MOS tube is connected to the second step-down output end of the main control chip unit; a boost control unit, which is used to boost the DC voltage output by the DC power supply according to the boost instruction output by the main control chip unit, wherein the boost control unit includes a third MOS tube and a fourth MOS tube, wherein the drain of the third MOS tube is used to be directly or indirectly connected to the system, the gate of the third MOS tube is connected to the first boost control terminal of the main control chip unit, the source of the third MOS tube is respectively connected to the first boost output terminal of the main control chip unit, the source of the first MOS tube, the drain of the second MOS tube and the drain of the fourth MOS tube, the gate of the fourth MOS tube is connected to the second boost control terminal of the main control chip unit, and the source of the fourth MOS tube is respectively connected to the second boost output terminal of the main control chip unit and the source of the second MOS tube; A battery charge and discharge control unit, when the battery power is lower than 100% and the DC power supply is provided, the VOUT output is used to power the system; when the DC power supply is not provided, the battery charge and discharge control unit controls the battery to power the system according to the battery power supply instruction output by the main control chip unit.

2. The buck-boost control circuit compatible with battery charge and discharge functions according to claim 1, characterized in that: The DC power supply is respectively connected to the SHDN pin, the VIN_REG pin, the PVIN pin, the SENSVIN pin, the SENSTOP pin and the drain of the first MOS tube of the main control chip unit; A first resistor for voltage stabilization is connected between the DC power supply and the drain of the first MOS tube, the SENSVIN pin is connected to a node between the DC power supply and the first resistor, and the SENSTOP pin is connected to a node between the DC power supply and the drain of the first MOS tube; A coupling unit is connected to a node between the DC power supply and the first resistor. The coupling unit includes a plurality of first capacitors connected in parallel. Each of the first capacitors is grounded.

3. The buck-boost control circuit compatible with battery charge and discharge functions according to claim 1, characterized in that: The main control chip unit also includes a pressure difference adjustment unit for adjusting the built-in pressure difference of the first MOS tube, the second MOS tube, the third MOS tube and the fourth MOS tube, and the pressure difference adjustment unit includes the INTVCC pin of the main control chip unit and a second capacitor, a first diode and a second diode connected in parallel with the INTVCC pin; One end of the second capacitor, the anode of the first diode and the anode of the second diode are all connected to the INTVCC pin, the other end of the second capacitor is grounded, the cathode of the first diode is connected to the node between the BST1 pin of the main control chip unit and the source of the first MOS tube, and a third capacitor for coupling is connected between the cathode of the first diode and the source of the first MOS tube; The cathode of the second diode is connected to a node between the BST2 pin of the main control chip unit and the source of the third MOS tube, and a fourth capacitor for coupling is connected between the cathode of the second diode and the source of the first MOS tube.

4. The buck-boost control circuit compatible with battery charge and discharge functions according to claim 1, characterized in that: A first undervoltage protection unit is arranged between the SHDN pin of the main control chip unit and the DC power supply, and the first undervoltage protection unit includes a second resistor and a third resistor arranged in series, wherein one end of the second resistor is connected to the DC power supply, the other end of the second resistor is connected to one end of the third resistor, the other end of the third resistor is grounded, and the SHDN pin of the main control chip unit is connected to a node between the second resistor and the third resistor.

5. The buck-boost control circuit compatible with battery charge and discharge functions according to claim 1, characterized in that: A second undervoltage protection unit is arranged between the VIN_REG pin of the main control chip unit and the DC power supply, and the second undervoltage protection unit includes a fourth resistor and a fifth resistor arranged in series, wherein one end of the fourth resistor is connected to the DC power supply, the other end of the fourth resistor is connected to one end of the fifth resistor, the other end of the fifth resistor is grounded, and the VIN_REG pin of the main control chip unit is connected to the node between the fourth resistor and the fifth resistor.

6. The buck-boost control circuit compatible with battery charge and discharge functions according to claim 1, characterized in that: A sixth resistor for voltage stabilization is connected to a node between the SENSGND pin of the main control chip unit and the source of the third MOS tube and the source of the fourth MOS tube.

7. The buck-boost control circuit compatible with battery charge and discharge functions according to claim 1, characterized in that: A first power supply protection unit is provided between the VFBMAX pin and the FBG pin of the main control chip unit and the system, and the first power supply protection unit includes a seventh resistor, an eighth resistor and a ninth resistor connected in series in sequence; The output end of the seventh resistor is used to be connected to the system, the input end of the ninth resistor is used to be connected to the FBG pin, and the VFBMAX pin is connected to a node between the eighth resistor and the ninth resistor.

8. The buck-boost control circuit compatible with battery charge and discharge functions according to claim 1, characterized in that: A second power supply protection unit is provided between the VFB pin and the FBG pin of the main control chip unit and the system, and the second power supply protection unit includes a tenth resistor, an eleventh resistor and a twelfth resistor connected in series in sequence; Among them, the output end of the tenth resistor is used to connect to the BAT pin of the main control chip unit, the input end of the twelfth resistor is used to connect to the FBG pin, and the VFB pin is connected to the node between the eleventh resistor and the twelfth resistor.

9. The buck-boost control circuit compatible with battery charge and discharge functions according to claim 2, characterized in that: The NTC pin of the main control chip unit is connected to a third power supply protection unit for protecting the power supply voltage of the PVIN pin. The third power supply protection unit is a thermistor that changes with the operating temperature of the main control chip unit, thereby changing the power supply voltage of the PVIN pin.

10. The buck-boost control circuit compatible with battery charge and discharge functions according to claim 1, characterized in that: The TIMER pin of the main control chip unit is connected to a charging time limiting unit for limiting the battery charging time, and the charging time limiting unit is an MLCC capacitor.

11. The buck-boost control circuit compatible with battery charge and discharge functions according to claim 1, characterized in that: A battery charge and discharge control unit is included, and the battery charge and discharge control unit includes: a fifth MOS tube, wherein the gate of the fifth MOS tube is connected to the first control end of the main control chip unit, and the source of the fifth MOS tube is connected to the system through a thirteenth resistor; the CSP pin of the main control chip unit is connected to a node between the thirteenth resistor and the system through a fourteenth resistor; the CSN pin of the main control chip unit is connected to a node between the thirteenth resistor and the source of the fifth MOS tube through a fifteenth resistor; the drain of the fifth MOS tube is grounded through a fifth capacitor for coupling; when the battery is in a discharging state, the discharge voltage of the battery supplies power to the system through the fifth MOS tube and the thirteenth resistor; a sixth MOS tube, wherein the drain of the sixth MOS tube is respectively connected to the node between the drain of the fifth MOS tube and the fifth capacitor and the second control end of the main control chip unit, and the source of the sixth MOS tube is directly or indirectly connected to the battery; a seventh MOS tube, wherein the gate of the seventh MOS tube is connected to the power supply end through the delay unit, the drain of the seventh MOS tube is grounded, the source of the seventh MOS tube is connected to the drain of the sixth MOS tube, and is used to control the conduction or cutoff of the sixth MOS tube; when the battery is in a charging state, the charging voltage supplied to the battery charges the battery through the sixth MOS tube.

12. The buck-boost control circuit compatible with battery charge and discharge functions according to claim 11, characterized in that: The delay unit includes a resistor and a capacitor arranged in series, the input end of the resistor is connected to the power supply end, the gate of the seventh MOS tube is connected to the node between the resistor and the capacitor, and the capacitor is grounded.

13. The buck-boost control circuit compatible with battery charge and discharge functions according to claim 11, characterized in that: An antistatic unit and a filter unit are arranged between the battery charge and discharge control unit and the battery, the antistatic unit is a diode, and the filter unit is a first filter capacitor and a second filter capacitor arranged in parallel; wherein the positive electrode of the diode is grounded, the negative electrode of the diode and one end of the first filter capacitor and the second filter capacitor are respectively connected to the output end of the battery charge and discharge control circuit, and the other ends of the first filter capacitor and the second filter capacitor are grounded.

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