Protocol level control circuit and mobile power supply thereof

Abstract

The invention relates to the technical field of lithium batteries, in particular to a protocol level control circuit and a mobile power supply thereof. Comprising a lithium battery protection module, a DC-DC module, an interface module and a discharge module, the voltage input end of the lithium battery protection module and the voltage input end of the DC-DC module are both connected with the positive electrode of the lithium battery, the voltage output end of the DC-DC module is connected with the interface module, and the protocol end of the DC-DC module is connected with the protocol end of the interface module; the voltage input end of the discharge module is connected with the anode of the lithium battery, and the voltage output end of the discharge module is respectively connected with the cathode of the lithium battery and grounded; a discharge module is arranged in a protocol level control circuit, when a lithium battery protection module triggers power-down protection, virtual electricity existing in a lithium battery protection mechanism is subjected to voltage division through the discharge module to lower voltage between a positive electrode of a lithium battery and a negative electrode of the lithium battery, so that a system protocol is converted into a charging mode under a low potential; and the phenomenon that the battery cell cannot be charged after over-discharging or short-circuit testing is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, in particular to a protocol level control circuit and a mobile power source thereof. Background Art

[0002] When an abnormality occurs in the lithium battery, the lithium protection protection will be triggered. When the battery enters the lithium protection protection, the mainboard or DC-DC cannot be removed, causing the lithium protection to determine that the fault has not been removed and cannot self-recover. At this time, the lithium protection detection mechanism always has virtual electricity; and the system's charging protocol USB PD has bidirectional high-power power transmission, which can be used as a power source to transmit current to the outside, and can also be used as a power receiving direction to charge inward. If the lithium protection detection mechanism always has virtual electricity, the system protocol will not be able to enter a low level, making it impossible for the system to switch from power supply mode to power receiving mode, resulting in the system being unable to charge and activate.

[0003] Therefore, it is very important for those skilled in the art to design a protocol level control circuit and a mobile power supply that can ensure that the system is normally charged and activated after the lithium protection is triggered. Summary of the invention

[0004] The technical problem to be solved by the embodiments of the present invention is to provide a protocol level control circuit and a mobile power supply thereof that can ensure that the system is normally charged and activated after the lithium protection is triggered, so as to solve the problem in the prior art that the system cannot be switched from the power supply mode to the power receiving mode, thereby causing the system to be unable to be charged and activated.

[0005] The present invention discloses a protocol level control circuit, which is used in a bidirectional charging and discharging power supply. The scheme of the circuit is that it comprises: a lithium battery protection module, a DC-DC module, an interface module and a discharge module; the voltage input end of the lithium battery protection module and the voltage input end of the DC-DC module are both connected to the lithium battery, the voltage output end of the DC-DC module is connected to the interface module, and the protocol end of the DC-DC module is connected to the protocol end of the interface module for switching the charging and discharging mode; the voltage input end of the discharge module is connected to the positive electrode of the lithium battery, the first voltage output end of the discharge module is grounded, and the second voltage output end of the discharge module is connected to the negative electrode of the lithium battery for dividing the voltage between the positive and negative electrodes of the lithium battery.

[0006] Optionally, the discharge module includes a switch unit and a voltage divider unit, the voltage input end of the switch unit is connected to the positive electrode of the lithium battery, the first voltage output end of the switch unit is connected to one end of the voltage divider unit, the other end of the voltage divider unit is grounded, and the second voltage output end of the switch unit is connected to the negative electrode of the lithium battery.

[0007] Optionally, the switch unit includes a first MOS tube and a second MOS tube, the source of the first MOS tube is connected to the positive electrode of the lithium battery, the drain of the first MOS tube is connected to the voltage divider unit, the gate of the first MOS tube is respectively connected to the positive electrode of the lithium battery and the drain of the second MOS tube, the gate of the second MOS tube is grounded, and the source of the second MOS tube is connected to the negative electrode of the lithium battery.

[0008] Optionally, the voltage dividing unit is a voltage dividing resistor.

[0009] Optionally, a first protection resistor is connected in series to the gate of the first MOS transistor.

[0010] Optionally, a second protection resistor is connected in series to the gate of the second MOS transistor, and a third protection resistor is connected in series between the gate of the second MOS transistor and the source of the second MOS transistor.

[0011] Optionally, the lithium battery protection module includes a lithium battery protection chip and a charge and discharge MOS tube, the voltage input pin of the lithium battery protection chip is connected to the positive electrode of the lithium battery, the voltage output pin of the lithium battery protection chip is connected to the negative electrode of the lithium battery, and the control pin of the lithium battery protection chip is connected to the charge and discharge MOS tube.

[0012] Optionally, the DC-DC module includes a buck-boost chip and a protocol chip, and the protocol chip serves as its protocol end for connecting to a protocol end of an interface module.

[0013] Optionally, the interface module includes a TYPE-C interface.

[0014] In order to solve the problems existing in the prior art, the present invention also provides a mobile power supply, which includes a circuit board, a lithium battery and a shell, the circuit board and the lithium battery are both arranged in the shell, the circuit board is provided with the protocol level control circuit as described above, and the lithium battery and the protocol level control circuit are electrically connected.

[0015] Compared with the prior art, the beneficial effect of the protocol level control circuit provided by the embodiment of the present invention is that: by setting a discharge module in the protocol level control circuit, when the lithium battery protection module triggers the power-off protection, the virtual electricity inside the lithium battery protection mechanism will be divided by the discharge module, so that the voltage between the positive electrode B+ of the lithium battery and the negative electrode B- of the lithium battery is 0, so as to lower the protocol pin level in the DC-DC module, so that the system is converted to charging mode at a low potential, effectively solving the problem that the battery cell cannot be charged after over-discharge or short-circuit test. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, in which:

[0017] Figure 1 The structure frame of the protocol level control circuit provided by the embodiment of the present invention is Figure 1 ;

[0018] Figure 2 is a circuit diagram of a lithium battery protection module provided by an embodiment of the present invention;

[0019] Figure 3 is a circuit diagram of a discharge module provided in an embodiment of the present invention;

[0020] Figure 4 The structure frame of the protocol level control circuit provided by the embodiment of the present invention is Figure 2 . DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, the preferred embodiments of the present invention are described in detail.

[0022] like Figures 1 to 4 As shown, the present invention provides a specific embodiment of a protocol level control circuit.

[0023] A protocol level control circuit, the protocol level control circuit is used in a bidirectional charging and discharging power supply, reference Figure 1 The protocol level control circuit includes a lithium battery protection module 100, a DC-DC module 200, an interface module 300 and a discharge module 400.

[0024] Among them, the voltage input end of the lithium battery protection module 100 and the voltage input end of the DC-DC module 200 are both connected to the positive electrode B+ of the lithium battery, the voltage output end of the DC-DC module 200 is connected to the interface module 300, and the protocol end of the DC-DC module 200 is connected to the protocol end of the interface module 300 for switching the charge and discharge mode; the voltage input end of the discharge module 400 is connected to the positive electrode B+ of the lithium battery, the first voltage output end of the discharge module 400 is grounded, and the second voltage output end of the discharge module 400 is connected to the negative electrode B- of the lithium battery for lowering the potential between the positive electrode B+ and the negative electrode B- of the lithium battery after voltage division.

[0025] Specifically, refer to Figure 1The lithium battery protection module 100 is connected to an external lithium battery to protect the lithium battery from overcharging, overdischarging, overcurrent and short circuit, thereby preventing the lithium battery from overheating, fire or even explosion; when the lithium battery voltage exceeds the set threshold, the lithium battery protection module 100 will disconnect the battery from the charger to prevent the battery from overcharging; when the lithium battery voltage is lower than the set threshold, the lithium battery protection module 100 will cut off the output of the power supply to prevent the battery from overdischarging; when the lithium battery outputs too much current, the lithium battery protection module 100 will limit the current to avoid damage to the battery or other equipment; when the lithium battery is short-circuited, the lithium battery protection module 100 will also immediately cut off the battery output to prevent danger.

[0026] Further, refer to Figure 1 The DC-DC module 200 is used for step-up and step-down output and protocol conversion. On the one hand, the voltage input terminal of the DC-DC module 200 is connected to the positive electrode B+ of the external lithium battery to convert one DC voltage into another DC voltage. The DC-DC module 200 can achieve both step-up and step-down or both step-up and step-down at the same time. On the other hand, the DC-DC module 200 is also used for protocol conversion of bidirectional charging and discharging power supply so that the power supply can switch between the power receiving end and the power sending end.

[0027] Further, refer to Figure 1 The voltage input end of the interface module 300 is connected to the voltage output end of the DC-DC module 200, and the voltage output end of the interface module 300 is used to connect to an external terminal device or an adapter. The protocol end of the interface module 300 is connected to the protocol end of the DC-DC module 200. The DC-DC module 200 can switch the protocol so that the interface module 300 can serve as both a receiving end and a power supply end. When the interface module 300 is connected to the adapter, the DC-DC module 200 switches the protocol to the charging mode, and the interface module 300 serves as a receiving end and charges the lithium battery. When the interface module 300 is connected to an external terminal device, the DC-DC module 200 switches the protocol to the discharging mode, and the interface module 300 serves as a power supply end and charges the external terminal device.

[0028] Further, refer to Figure 1 The voltage input terminal of the discharge module 400 is connected to the positive electrode B+ of the lithium battery, the first voltage output terminal of the discharge module 400 is grounded, and the second voltage output terminal of the discharge module 400 is connected to the negative electrode B- of the lithium battery, so as to lower the potential between the positive electrode B+ and the negative electrode B- of the lithium battery after voltage division, that is, to divide the voltage between the positive electrode B+ and the negative electrode B- of the lithium battery.

[0029] In the production process of lithium batteries, short-circuit testing of lithium battery cells is a very important part to ensure the quality and safety of the cells. At present, for some products with bidirectional high-power power transmission, it is easy for the cells to be over-discharged or unable to be charged after short-circuit testing. This is mainly because after the lithium battery protection module triggers the power-off protection, the main board or DC-DC module cannot be removed, so the lithium battery protection module determines that the fault cannot be removed and cannot be self-recovered. At this time, there is always virtual electricity inside the lithium battery protection mechanism, making it difficult for the system protocol conversion to be converted from the power supply mode to the power receiving mode, and charging activation cannot be performed.

[0030] In order to solve the above problem, this embodiment sets a discharge module in the protocol level control circuit. When the lithium battery protection module triggers the power-off protection, the virtual electricity inside the lithium battery protection mechanism will be divided by the discharge module, so that the voltage between the positive electrode B+ of the lithium battery and the negative electrode B- of the lithium battery is 0, so as to lower the protocol pin level and convert the system into charging mode at a low potential, so as to solve the problem that the battery cell cannot be charged after over-discharge or short-circuit test.

[0031] In one embodiment, reference Figure 2 The lithium battery protection module 100 includes a lithium battery protection chip U1 and a charge and discharge MOS tube Q1. The voltage input pin of the lithium battery protection chip U1 is connected to the positive electrode B+ of the lithium battery, the voltage output pin of the lithium battery protection chip U1 is connected to the negative electrode B- of the lithium battery, and the control pin of the lithium battery protection chip U1 is connected to the charge and discharge MOS tube Q1.

[0032] Specifically, refer to Figure 2 The lithium battery protection chip U1 and the charge and discharge MOS tube Q1 serve as a bridge between the DC-DC module 200 and the lithium battery. They are mainly responsible for overcharge protection, over-discharge protection, overcurrent protection and short circuit protection to ensure that the battery cell is within a safe range. For example, overcharge protection: During the charging process of the lithium battery, as the voltage increases to the upper limit voltage of the battery cell, it will bring uncertain dangers. During the real-time monitoring of the battery voltage, the lithium battery protection chip U1 will control the charge and discharge MOS tube Q1 to be turned off when the battery is charged to a safe voltage range point, so as to cut off the power supply and prevent the voltage from continuing to rise, thereby playing a protective role.

[0033] In one embodiment, reference Figure 3 The discharge module 400 includes a switch unit 410 and a voltage divider unit 420. The voltage input terminal of the switch unit 410 is connected to the positive electrode B+ of the lithium battery, the first voltage output terminal of the switch unit 410 is connected to one end of the voltage divider unit 420, and the other end of the voltage divider unit 420 is grounded; the second voltage output terminal of the switch unit 410 is connected to the negative electrode B- of the lithium battery.

[0034] Specifically, refer to Figure 3When the lithium battery protection module 100 triggers the lithium battery protection, the charging MOS tube or the discharging MOS tube will be disconnected accordingly, and the power supply of the DC-DC module 200 will be cut off. However, since there are dormant detection mechanisms such as charger detection and load detection inside the system, the detection mechanism will have some microampere-level current. The existence of this current will generate a virtual voltage for the DC-DC module 200. If the virtual voltage is not divided, the protocol end of the DC-DC module 200 cannot be pulled down to a low potential, the protocol state cannot be converted, and the charging mode cannot be entered, so that the product cannot be charged and activated.

[0035] Due to the existence of the discharge module 400, its switch unit 410 is turned on after the charging MOS tube or the discharging MOS tube is disconnected, so that the virtual electricity in the lithium battery protection module 100 is divided by the voltage divider unit 420, thereby ensuring that the voltage between the positive electrode B+ of the lithium battery and the negative electrode B- of the lithium battery is 0, so that the protocol end of the DC-DC module 200 is pulled down, ensuring the normal conversion of the protocol state, and the product enters the charging mode. When the charger is connected, the product will be charged and activated.

[0036] In one embodiment, reference Figure 3 The switch unit 410 includes a first MOS tube Q2 and a second MOS tube Q3, a source electrode S of the first MOS tube Q2 is connected to the positive electrode B+ of the lithium battery, a drain electrode D of the first MOS tube Q2 is connected to the voltage dividing unit 420, a gate electrode G of the first MOS tube Q2 is connected to the positive electrode B+ of the lithium battery and a drain electrode D of the second MOS tube Q3 respectively, a gate electrode G of the second MOS tube Q3 is grounded, and a source electrode S of the second MOS tube Q3 is connected to the negative electrode B- of the lithium battery.

[0037] Specifically, refer to Figure 3 The second MOS tube Q3 is an NMOS tube. When the voltage of the gate G of the second MOS tube Q3 is higher than the voltage of the source S, the second MOS tube Q3 is turned on. Since the source S of the second MOS tube Q3 is connected to the negative electrode B- of the lithium battery, the gate G of the second MOS tube Q3 is grounded, and the drain D of the second MOS tube Q3 is respectively connected to the positive electrode B+ of the lithium battery and the gate G of the first MOS tube Q2. When the charging MOS tube or the discharging MOS tube is disconnected, the virtual electricity in the lithium battery protection module 100 will instantly pull up the ground terminal, so that the gate G of the second MOS tube Q3 is pulled up, and the source S of the second MOS tube Q3 connected to the negative electrode B- of the lithium battery is at a low potential, so that the gate G voltage of the second MOS tube Q3 is higher than the source S voltage of the second MOS tube Q3, and the second MOS tube Q3 is turned on.

[0038] Further, refer to Figure 3The first MOS tube Q2 is a PMOS tube. When the voltage of the gate G of the first MOS tube Q2 is lower than the voltage of the source S, the first MOS tube Q2 is turned on. Since the source S of the first MOS tube Q2 is connected to the positive electrode B+ of the lithium battery, the drain D of the first MOS tube Q2 is connected to the voltage dividing unit 420. When the second MOS tube Q3 is turned on, the gate G of the first MOS tube Q2 is pulled down, and the source S of the first MOS tube Q2 connected to the positive electrode B+ of the lithium battery is at a high potential. The first MOS tube Q2 is turned on. At this time, the virtual voltage of the positive electrode B+ of the lithium battery will pass through the first MOS tube Q2 and be discharged by the voltage dividing unit 420 to ensure that the loop potential between the positive electrode B+ of the lithium battery and the negative electrode B- of the lithium battery is pulled down.

[0039] In one embodiment, reference Figure 3 , the voltage dividing unit 420 is a voltage dividing resistor R1.

[0040] In one embodiment, reference Figure 3 A first protection resistor R2 is connected in series to the gate G of the first MOS tube Q2; a second protection resistor R3 is connected in series between the gate G of the second MOS tube Q3 and the ground line, a fourth protection resistor R5 is connected in series between the gate G of the second MOS tube Q3 and the negative electrode B- of the lithium battery, and a third protection resistor R4 is connected in series between the gate G of the second MOS tube Q3 and the source S of the second MOS tube Q3.

[0041] Specifically, refer to Figure 3 By connecting a protective resistor in series to the gate G of the first MOS tube Q2 and the gate G of the second MOS tube Q3, the flow of the gate G current can be limited to prevent the MOS tube or other circuit elements from being damaged by excessive current, which helps to stabilize the circuit. Further, the series protective resistor can also stabilize the voltage to prevent the voltage peak or excessive voltage change from damaging the MOS tube. Further, the series protective resistor can also help reduce the oscillation of the circuit and improve the stability and reliability of the circuit. Further, the series protective resistor can also play a filtering role.

[0042] In one embodiment, reference Figure 4 The DC-DC module 200 includes a buck-boost chip 210 and a protocol chip 220 , and the protocol chip 220 serves as a protocol end thereof for connecting with a protocol end of the interface module 300 .

[0043] Specifically, the buck-boost chip 210 is a power converter that can convert an input voltage into an output voltage, and the output voltage can be higher or lower than the input voltage. The chip combines the two topologies of buck and boost, and can provide a stable output voltage when the input voltage varies over a large range. When the output voltage is higher than the input voltage, it operates in boost mode, storing and releasing energy through periodic switching to increase the output voltage. When the output voltage is lower than the input voltage, it operates in buck mode, regulating the output voltage through periodic switching to reduce the output voltage.

[0044] Furthermore, the protocol chip 220 mainly adopts the USB PD protocol, which is a protocol standard for providing higher power through a USB connection. The USB PD protocol supports power transmission of up to 100 watts, which can charge mobile devices, laptops and other devices faster; the USB PD protocol allows two-way communication between devices to dynamically negotiate power demand and supply to achieve smarter charging management.

[0045] The USB PD protocol allows high-power power transmission between USB devices, and uses two roles, Sink and Source; Sink is the receiver, which is a device that needs power, equivalent to a laptop or mobile phone, and needs to be charged from the outside; Source is the sender, which is a device that can provide power, such as a charger, which can provide power to the USB PD Sink (receiver) to help it charge; the protocol conversion of the protocol chip 220 depends on the level on its protocol pin. When the protocol pin is pulled low, the role enters the Sink and can charge itself through an external charger. When the protocol pin is pulled high, the role enters the Source and acts as a charger to power external devices.

[0046] In one embodiment, the interface module 300 includes a TYPE-C interface.

[0047] Specifically, the TYPE-C interface is a new USB connection standard that supports the USB USB PD standard, can provide up to 100 watts of power output, and supports fast charging and power supply.

[0048] The present invention also provides a mobile power supply, which includes a circuit board, a lithium battery and a shell. The circuit board and the lithium battery are both arranged in the shell. The circuit board is provided with the protocol level control circuit as described above, and the lithium battery and the protocol level control circuit are electrically connected.

[0049] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the protection scope of the claims attached to the present invention.

Claims

1. A protocol level control circuit, used in a bidirectional charging and discharging power supply, characterized in that: include: Lithium battery protection module, DC-DC module, interface module and discharge module; The voltage input end of the lithium battery protection module and the voltage input end of the DC-DC module are both connected to the lithium battery, the voltage output end of the DC-DC module is connected to the interface module, and the protocol end of the DC-DC module is connected to the protocol end of the interface module for switching the charge and discharge mode; the voltage input end of the discharge module is connected to the positive electrode of the lithium battery, the first voltage output end of the discharge module is grounded, and the second voltage output end of the discharge module is connected to the negative electrode of the lithium battery for dividing the voltage between the positive and negative electrodes of the lithium battery.

2. The protocol level control circuit according to claim 1, characterized in that: The discharge module includes a switch unit and a voltage divider unit, wherein the voltage input end of the switch unit is connected to the positive electrode of the lithium battery, the first voltage output end of the switch unit is connected to one end of the voltage divider unit, the other end of the voltage divider unit is grounded, and the second voltage output end of the switch unit is connected to the negative electrode of the lithium battery.

3. The protocol level control circuit according to claim 2, characterized in that: The switch unit includes a first MOS tube and a second MOS tube, the source of the first MOS tube is connected to the positive electrode of the lithium battery, the drain of the first MOS tube is connected to the voltage dividing unit, the gate of the first MOS tube is respectively connected to the positive electrode of the lithium battery and the drain of the second MOS tube, the gate of the second MOS tube is grounded, and the source of the second MOS tube is connected to the negative electrode of the lithium battery.

4. The protocol level control circuit according to claim 2, characterized in that: The voltage dividing unit is a voltage dividing resistor.

5. The protocol level control circuit according to claim 2, characterized in that: A first protection resistor is connected in series to the gate of the first MOS tube.

6. The protocol level control circuit according to claim 2, characterized in that: A second protection resistor is connected in series to the gate of the second MOS tube, and a third protection resistor is connected in series between the gate of the second MOS tube and the source of the second MOS tube.

7. The protocol level control circuit according to claim 1, characterized in that: The lithium battery protection module includes a lithium battery protection chip and a charge and discharge MOS tube, the voltage input pin of the lithium battery protection chip is connected to the positive electrode of the lithium battery, the voltage output pin of the lithium battery protection chip is connected to the negative electrode of the lithium battery, and the control pin of the lithium battery protection chip is connected to the charge and discharge MOS tube.

8. The protocol level control circuit according to claim 1, characterized in that: The DC-DC module includes a step-up / step-down chip and a protocol chip, and the protocol chip serves as a protocol terminal thereof for connecting with the protocol terminal of the interface module.

9. The protocol level control circuit according to claim 1, characterized in that: The interface module includes a TYPE-C interface.

10. A mobile power source, characterized in that: It comprises a circuit board, a lithium battery and a shell, wherein the circuit board and the lithium battery are both arranged in the shell, the circuit board is provided with a protocol level control circuit as described in any one of claims 1-9, and the lithium battery and the protocol level control circuit are electrically connected.

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