A battery direct power supply system based on unipolar charging and bipolar power supply

Abstract

The present invention provides a battery direct power supply system based on unipolar charging and bipolar power supply, which includes a charging input interface, a fast charging protocol control circuit, a charging circuit, a battery pack, a main control circuit and a power control circuit. The fast charging protocol control circuit performs a connection handshake with a power adapter through the charging input interface to identify the charging protocol; the charging circuit is used to monitor the voltage and current of the battery pack, and configure the charging voltage of the battery pack according to the charging power supply and battery monitoring data; the power control circuit is used to control the input or cut off of the charging power supply according to the power control signal output by the main control circuit to achieve charging protection; the battery pack adopts a battery series stacking structure, which is used to provide a two-pole power supply with a zero-ground voltage output terminal for an audio circuit; the present invention directly powers the audio circuit by outputting a bipolar power supply from the battery pack, and can provide a power supply with low internal resistance, low noise and good stability for a high-quality audio circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of audio circuit power supply, and in particular to a battery direct power supply system based on unipolar charging and bipolar power supply. Background Art

[0002] At present, in order to adapt to the power supply form required by audio circuits, most of the power needs to be converted before supplying power, but this means that additional power conversion equipment, such as transformers, is required, which increases the complexity of the system and there is a risk of voltage instability during power conversion. Especially in an environment with poor power quality, the sound quality may have problems such as noise, hum, and voltage instability during power supply, affecting the performance and sound quality of the audio equipment.

[0003] Especially for audio amplifier circuits that pursue high sound quality, analog audio amplifier circuits are often very sensitive to the power supply system. If a low-quality power supply system with high noise, high dynamic internal resistance, and weak current output capacity is used, in addition to deteriorating the measurable performance indicators of the audio system such as signal-to-noise ratio, THD (total harmonic distortion) and dynamic range, it will also cause the subjective listening experience of the audio system to present undesirable characteristics such as fuzzy sound, poor clarity, unclean sound background, and poor appeal. Therefore, a power supply system with low internal resistance and low noise is a necessary condition for high-quality audio amplifier circuits, and traditional conversion power supplies cannot meet the power supply needs of high-quality audio amplifier circuits.

[0004] Battery power supply has the advantages of clean power supply without impurities and good power stability, which can better protect the sound quality. However, simply powering with a battery cannot meet the power supply needs of the audio circuit. For example, a lithium battery can provide positive and negative bipolar power supply, but cannot provide unipolar power supply. A single battery power supply does not meet the capacity requirements of the audio equipment and cannot provide long-term battery life. It is impossible to manage the battery charging and discharging and monitor the status of the battery itself.

[0005] Therefore, it is necessary to design a battery direct power supply system that can meet the power supply requirements of high-quality audio circuits. Summary of the invention

[0006] In order to solve the common problems in the prior art, the purpose of the present invention is to provide a battery direct power supply system based on unipolar charging and bipolar power supply. The invention directly powers the audio circuit by outputting a bipolar power supply through a battery pack, and can provide a power supply with low internal resistance, low noise and good stability for high-quality audio circuits.

[0007] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0008] A battery direct power supply system based on unipolar charging and bipolar power supply, comprising:

[0009] The charging input interface, the fast charging protocol control circuit, the charging circuit and the battery pack also include a main control circuit and a power control circuit. The charging input interface is a unipolar charging interface, which is used to connect to an external power adapter to input charging power; the fast charging protocol control circuit performs a connection handshake with the power adapter through the charging input interface to identify the charging protocol, and according to the charging protocol, the power adapter adjusts the voltage and current of the charging power output according to the charging needs of the receiving end; the input end of the charging circuit is connected to the charging input interface through the power control circuit to input the charging power, and its output end is connected to the battery pack for The voltage and current of the battery pack are monitored, and the charging voltage of the battery pack is configured according to the charging power supply and battery monitoring data; the charging circuit establishes a communication connection with the main control circuit to transmit the battery monitoring data to the main control circuit, and the main control circuit is used to process and analyze the monitoring data and output a power control signal to the power control circuit; the power control circuit is used to control the input or cut-off of the charging power supply in the charging circuit according to the power control signal to achieve charging protection; the battery pack adopts a battery series stacking structure to provide a two-pole power supply with a zero-ground voltage output terminal for the audio circuit.

[0010] Among them, the battery pack is a series battery pack composed of an even number of pairs of battery cells connected in series, the positive and negative electrodes of the two-pole power supply are respectively led out from the head end and the tail end of the series battery pack, and the neutral-ground voltage output terminal is led out from the common connection end of the two middle battery cells of the series battery pack.

[0011] According to a battery direct power supply system based on unipolar charging and bipolar power supply provided by the present invention, the charging input interface adopts a USB Type-C interface. When connected to the power adapter through the USB Type-C interface and powered on, the fast charging protocol control circuit and the power adapter exchange information through an electronic dialogue. The exchanged information includes but is not limited to the fast charging protocol version supported by the receiving end and the maximum receiving current. After the handshake is successful, the power adapter adjusts its output voltage and current according to the charging needs of the receiving end.

[0012] According to a battery direct power supply system based on unipolar charging and bipolar power supply provided by the present invention, the fast charging protocol control circuit includes a Type-C receiving end fast charging protocol control chip and its peripheral circuits. The Type-C receiving end fast charging protocol control chip has built-in PD3.1 protocol, PD3.0 / 2.0 protocol, QC3.0 / 2.0 protocol and many private fast charging protocols, and is compatible with 5.0V traditional USB charging protocol, so as to achieve compatibility with multiple external power supplies to provide the charging power.

[0013] According to a battery direct power supply system based on unipolar charging and bipolar power supply provided by the present invention, the charging circuit includes a battery charging management IC model BQ25703A and its peripheral circuits, and the battery charging management IC has high-precision adjustment and monitoring functions, including ±0.5% charging voltage adjustment and ±2% input / charging current adjustment, which is used to adjust the voltage according to the input charging power supply and the battery pack status and synchronize the battery pack voltage reduction or increase; and has an integrated ADC for monitoring the voltage, current and power of the battery pack.

[0014] According to a battery direct power supply system based on unipolar charging and bipolar power supply provided by the present invention, it also includes multiple battery cell balancing detection circuits, and the multiple battery cell balancing detection circuits are respectively connected to the multiple battery cells of the battery pack, and are respectively used to detect the balancing state of each battery cell, and output the detected balancing state signal to the main control circuit. The main control circuit controls the charging current output by the battery charging management IC according to the balancing state signal.

[0015] Among them, when the main control circuit detects that more than one battery cell enters a balanced state, the battery cell is detected again through the battery cell balanced detection circuit after waiting for 30 seconds. If the battery cell is still in a balanced state, the battery charging management IC is configured through the I²C interface to reduce the charging current output by the battery charging management IC from 1.2A to 400mA.

[0016] Among them, when the main control circuit detects that the balancing state of more than one battery cell has been eliminated, the battery cell is detected again through the battery cell balancing detection circuit after waiting for 30 seconds. If the battery cell is still in the balancing elimination state, the battery charging management IC is configured through the I²C interface to restore the charging current output by the battery charging management IC to 1.2A.

[0017] According to the present invention, a battery direct power supply system based on unipolar charging and bipolar power supply also includes a battery protection circuit, wherein the battery protection circuit includes a battery pack protection circuit, a plurality of battery cell protection circuits having the same circuit structure as the number of battery cells in the battery pack, and a balanced current control circuit. Multiple battery cell protection circuits are connected in series, the positive power pole of the battery cell protection circuit at the head end is connected to the positive pole of the charging power supply, and the negative power pole of the battery cell protection circuit at the tail end is connected to the negative pole of the charging power supply. The positive and negative power poles of the multiple battery cell protection circuits are respectively connected to the positive and negative ends of the multiple battery cells, and are respectively used to individually control the charging and discharging of each of the battery cells; the battery pack protection circuit is used for voltage, current and temperature protection of the battery pack, and it has a stackable battery voltage sensing interface, which is used to adjust the battery protection scale according to the number of battery cells in the battery pack; the control ends of the multiple balancing current control circuits are respectively connected to the multiple battery voltage sensing interfaces of the battery pack protection circuit, and their input and output ends are respectively connected to the positive and negative ends of the multiple battery cells in the battery pack, and are used to perform balancing management on each of the battery cells according to the control signal output by the battery pack protection circuit.

[0018] According to a battery direct power supply system based on unipolar charging and bipolar power supply provided by the present invention, the battery cell protection circuit includes a battery protection IC, a charging FET and a discharging FET, the battery protection IC is provided with a charging control end and a discharging control end, the battery protection IC is connected to the control end of the charging FET through the charging control end, and is connected to the control end of the discharging FET through the discharging control end, the input and output ends of the charging FET and the discharging FET are respectively connected to the positive and negative electrodes of the battery cell, and are respectively used for charging and discharging control of the battery cell.

[0019] According to a battery direct power supply system based on unipolar charging and bipolar power supply provided by the present invention, the battery pack protection circuit adopts a stackable low-power battery pack protector model BQ77915, and its stackable interface supports the extended application of multi-battery unit series battery packs; it has a variety of configured protection thresholds, provides separate over-temperature and under-temperature thresholds for the discharge and charging of the battery pack and provides an adjustable discharge over-current protection delay; it implements a passive battery balancing algorithm through an integrated FET, so that the battery balancing current of the battery pack can reach up to 50 mA.

[0020] According to a battery direct power supply system based on unipolar charging and bipolar power supply provided by the present invention, the balancing current control circuit is an external balancing circuit provided in the battery pack protection circuit, which includes a MOSFET and a shunt resistor, the control end of the MOSFET is connected to the battery voltage sensing interface of the battery pack protection circuit, its current input end is connected to the positive electrode of the battery cell through the shunt resistor, and its output end is connected to the negative electrode of the battery cell through the input and output ends of the charging FET and the discharging FET, and the MOSFET is controlled to be turned on by the battery pack protection circuit outputting a control signal, so that the battery balancing current is increased to about 330mA.

[0021] According to a battery direct power supply system based on unipolar charging and bipolar power supply provided by the present invention, it also includes a power supply output interface, the power supply output interface includes the positive and negative poles of the bipolar power supply and the zero-ground voltage output end, the power supply output interface is externally connected to a power supply decoupling filter circuit, the power supply decoupling filter circuit includes a first electrolytic capacitor, a second electrolytic capacitor, a first bypass capacitor and a second bypass capacitor, the first electrolytic capacitor and the first bypass capacitor are both connected in parallel to the positive pole of the bipolar power supply and the zero-ground voltage output end, and are respectively used to filter out high-frequency interference and high-frequency noise for the positive power supply output to the audio circuit; the second electrolytic capacitor and the second bypass capacitor are both connected in parallel to the negative pole of the bipolar power supply and the zero-ground voltage output end, and are respectively used to filter out high-frequency interference and high-frequency noise for the negative power supply output to the audio circuit.

[0022] Among them, the positive power supply output to the audio circuit includes a bipolar positive power supply of +5.8V to +8.4V and a unipolar positive power supply of +11.6V to +16.8V; the negative power supply output to the audio circuit includes a bipolar negative power supply of -5.8V to -8.4V and a unipolar 0V power supply.

[0023] The power source output from the neutral voltage output terminal to the audio circuit is a bipolar 0V center reference voltage.

[0024] It can be seen that compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention provides a bipolar power supply with a zero-ground voltage output terminal for an audio circuit by stacking batteries in series to form a battery pack. Compared with the traditional power supply method using a conversion power supply, the direct power supply method of the battery can provide a power supply with low internal resistance, low noise and stable voltage for the audio circuit. Compared with the simple power supply method using a battery, a high-performance audio amplifier circuit, especially an earphone amplifier circuit with high swing and high power output, needs to use a symmetrical positive and negative bipolar power supply with equal voltage values. The series stacked battery pack structure of the present invention can realize bipolar power supply and unipolar power supply through different connection methods, and monitor the battery pack and adjust the charging voltage and current with high precision through the charging circuit to ensure the safety and efficiency of the charging process; the battery protection circuit monitors and controls the entire charging and discharging process of the battery pack in real time to achieve comprehensive protection against abnormal situations such as overcharging, overdischarging and short circuit, and dynamically adjusts the charging current of each battery cell in real time through balanced current control, so that each battery cell reaches a full state at the same time, thereby ensuring the safety and stability of the entire battery pack to the greatest extent, greatly extending the battery life, and meeting the power supply requirements of high-quality audio circuits.

[0026] 2. The power supply system of the present invention adopts a Type-C receiving-end fast charging protocol control chip, with built-in mainstream PD3.1, PD3.0 / 2.0, QC3.0 / 2.0 and multiple private fast charging protocols, and is compatible with the 5.0V traditional USB charging protocol. It has a wide input voltage range and can obtain appropriate voltage and current from power sources such as mobile phone power adapters, car chargers, and power banks to charge the battery pack. Therefore, it has strong compatibility with power sources, making it easy for users to choose appropriate power charging solutions according to their needs.

[0027] 3. The present invention uses a battery charging management IC to perform synchronous battery buck / boost charging control on a battery pack, and can seamlessly switch between buck and boost, so there is no dead zone to ensure efficient conversion between different modes; it can automatically detect the maximum capacity of the input power to optimize the current, while maintaining the consistency of the system and the charging current to ensure the maximum input power is utilized, and can achieve efficient power management; and it can allow the main control circuit to configure the output current through the I²C interface, thereby achieving battery balancing current regulation.

[0028] 4. The present invention controls the power control switch of the charging circuit to turn on or off the input power of the charging circuit through the main control circuit. When charging is completed, the power supply automatically cuts off the input power to achieve charging protection. The main control circuit, as the control center of the power supply system, can not only achieve the above-mentioned charging protection, but also achieve battery balancing adjustment by combining the overcharge protection detection and battery balancing state detection of the battery protection circuit to avoid overcharging and over-discharging.

[0029] 5. The battery protection circuit of the present invention adopts an ultra-low power consumption battery pack protector for battery pack voltage, current and temperature protection, a high-performance, low-power consumption battery protection IC for providing over-temperature protection, over-voltage protection and under-voltage protection for each battery cell, and a balancing current control circuit for increasing the battery balancing current, which can realize comprehensive protection of the battery pack and extend the battery life;

[0030] 6. The power supply system of the present invention is composed of four precisely matched low-resistance 18650 lithium-ion battery cells, which have extremely low output ripple noise and dynamic internal resistance and strong load capacity. The positive power supply and negative power supply output are combined with large-scale power supply filter decoupling capacitors to filter out high-frequency interference and high-frequency noise and then output to the headphone amplifier circuit of the audio device. It has the advantages of extremely low internal resistance and fast response, and can meet the power supply requirements of high-quality audio circuits.

[0031] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of an embodiment of a battery direct power supply system based on unipolar charging and bipolar power supply of the present invention.

[0033] Figure 2 The present invention is a circuit schematic diagram of a main control circuit and a status display circuit in an embodiment of a battery direct power supply system based on unipolar charging and bipolar power supply.

[0034] Figure 3 It is a circuit schematic diagram of a charging input interface, a power control circuit and a charging circuit in an embodiment of a battery direct power supply system based on unipolar charging and bipolar power supply of the present invention.

[0035] Figure 4 It is a circuit schematic diagram of a fast charging protocol control circuit in an embodiment of a battery direct power supply system based on unipolar charging and bipolar power supply of the present invention.

[0036] Figure 5 It is a circuit schematic diagram of a cell equalization detection circuit in an embodiment of a battery direct power supply system based on unipolar charging and bipolar power supply of the present invention.

[0037] Figure 6 It is a circuit schematic diagram of a battery protection circuit in an embodiment of a battery direct power supply system based on unipolar charging and bipolar power supply of the present invention.

[0038] Figure 7 It is a schematic diagram of an external power supply decoupling filter circuit in an embodiment of a battery direct power supply system based on unipolar charging and bipolar power supply of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0041] See also Figure 1 The present invention provides a battery direct power supply system based on unipolar charging and bipolar power supply, including a charging input interface 10, a fast charging protocol control circuit 20, a charging circuit 40 and a battery pack 70, and also includes a main control circuit 50 and a power control circuit 30. The charging input interface 10 is a unipolar charging interface, which is used to connect to an external power adapter 200 to input charging power; the fast charging protocol control circuit 20 connects and shakes hands with the power adapter 200 through the charging input interface 10 to identify the charging protocol, and according to the charging protocol, the power adapter 200 adjusts the voltage and current of the charging power output according to the charging needs of the receiving end; the input end of the charging circuit 40 is connected to the charging input interface 10 through the power control circuit 30 to input The charging power supply, whose output end is connected to the battery pack 70, is used to monitor the voltage and current of the battery pack 70, and configure the charging voltage of the battery pack 70 according to the charging power supply and battery monitoring data; the charging circuit 40 establishes a communication connection with the main control circuit 50, and is used to transmit the battery monitoring data to the main control circuit 50, and the main control circuit 50 is used to process and analyze the monitoring data, and output a power control signal to the power control circuit 30; the power control circuit 30 is used to control the input or disconnection of the charging power supply in the charging circuit 40 according to the power control signal to achieve charging protection; the battery pack 70 adopts a battery series stacking structure, and is used to provide a two-pole power supply with a zero-ground voltage output end for the audio circuit 400.

[0042] See also Figure 2Specifically, the main control circuit 50 of this embodiment includes an MCU controller and its peripheral circuits, and adopts an ultra-low power MCU of model STM8L151K6, which can operate under extremely low voltage conditions, and the operating voltage range is 1.8V to 3.6V; the MCU controller adopts an enhanced STM8 CPU core, which can provide a fast response of up to 16 MIPS at 16 MHz, and integrates a variety of peripherals, including Flash memory, SRAM, timer, A / D converter, D / A converter, comparator and serial interface, etc. The integration of these peripherals can reduce the demand for additional hardware, simplify the design, and reduce costs.

[0043] Specifically, this embodiment also includes a status display circuit, which includes four light-emitting diodes and resistors. The anodes of the light-emitting diodes are all connected to 3.3V DC, and the cathodes are respectively connected to ENLED4, EN LED3, EN L ED2, and EN LED1 enable signals from the MCU controller to display the status of the power supply system.

[0044] See also Figure 3 Specifically, the power control circuit 30 of this embodiment further includes a switch tube Q39, a switch tube Q40, a triode Q41 and a plurality of diodes. The base of the triode Q41 inputs a power control signal, the emitter thereof is grounded, the source is connected to the gate of the switch tube Q39 and the gate of the switch tube Q40 through a switch diode, the source of the switch tube Q39 is connected to the charging power supply, the drain thereof is connected to the drain of the switch tube Q40, and the source of the switch tube Q40 is connected to the power input terminal of the charging circuit 40.

[0045] Among them, when the power control signal is at a high level, the transistor Q41 is turned on, and the switch tube Q39 and the switch tube Q40 are both turned on, and the charging power input of the charging circuit 40 is turned on; when the power control signal is at a low level, the transistor Q41 is turned off, and the switch tube Q39 and the switch tube Q40 are both turned off, and the charging power input of the charging circuit 40 is turned off.

[0046] Specifically, in this embodiment, the switch tube Q39 and the switch tube Q40 are both 30V 35A PMOS tubes. The switch tube Q39 and the switch tube Q40 are connected in series back to back to realize the charging power input control of the charging circuit 40. This switch control method has the following advantages: (1) The switch tube Q39 and the switch tube Q40 share the current, which can avoid excessive current damaging the switch device; (2) Reduce electromagnetic interference. The back-to-back connection method can reduce the electromagnetic interference generated during the switching process; (3) Improve the reliability of the circuit. When one PMOS tube fails, the other PMOS tube can still continue to work.

[0047] The battery pack 70 is a series battery pack 70 composed of an even number of pairs of battery cells connected in series, the positive and negative electrodes of the two-pole power supply are respectively led out from the head end and the tail end of the series battery pack 70, and the neutral voltage output terminal is led out from the common connection end of the two middle battery cells of the series battery pack 70.

[0048] Specifically, this embodiment uses 4 low-resistance 18650 high-performance lithium batteries BAT1~BAT4 to form a battery pack 70. The capacity of the battery pack 70 is 3500mAh 14.8V, which can provide more than 12 hours of battery life for the audio host, and the charging time does not exceed 4 hours; it supports fast charging and standard charging, and supports charging while using.

[0049] Specifically, the present embodiment adopts an easy-to-plug modular interface to install the lithium battery pack 70, which is convenient for replacing the power module or battery cell and realizes an easy battery replacement mode.

[0050] In this embodiment, the charging input interface 10 adopts a USB Type-C interface. When connected to the power adapter 200 through the USB Type-C interface and powered on, the fast charging protocol control circuit 20 and the power adapter 200 exchange information through an electronic dialogue. The exchanged information includes but is not limited to the fast charging protocol version supported by the receiving end and the maximum receiving current. After the handshake is successful, the power adapter 200 adjusts its output voltage and current according to the charging needs of the receiving end.

[0051] See also Figure 4 In this embodiment, the fast charging protocol control circuit 20 includes a Type-C receiving end fast charging protocol control chip and its peripheral circuits. The Type-C receiving end fast charging protocol control chip has built-in PD3.1 protocol, PD3.0 / 2.0 protocol, QC3.0 / 2.0 protocol and many private fast charging protocols, and is compatible with 5.0V traditional USB charging protocol, so as to achieve compatibility with multiple external power supplies to provide the charging power.

[0052] See also Figure 3 In this embodiment, the charging circuit 40 includes a battery charging management IC of model BQ25703A and its peripheral circuits. The battery charging management IC has high-precision regulation and monitoring functions, including ±0.5% charging voltage regulation and ±2% input / charging current regulation, which is used to regulate the voltage according to the input charging power supply and the state of the battery pack 70 and synchronize the battery pack 70 with the voltage reduction or increase; and has an integrated ADC for monitoring the voltage, current and power of the battery pack 70.

[0053] Specifically, in this embodiment, a discharge current sensor is further provided on the connection line from the power supply control circuit 30 to the charging circuit 40. The discharge current sensor 10mΩ resistor R202 is used to provide discharge current data for the charging circuit 40. One end of the resistor R202 is connected to the source of the switch tube Q40, and is connected to the ACP pin of the battery charging management IC through the resistor R203, and the other end of the resistor R202 is connected to the ACP and VBUS pins of the battery charging management IC through the resistors R204 and R205, respectively.

[0054] Specifically, the charging circuit 40 of this embodiment is further provided with a charging current sensor on the output charging power PACK+ line. The charging current sensor is a 10 mΩ resistor R206 , which is used to provide charging current data for the charging circuit 40 .

[0055] Specifically, the BQ25703A battery charging management IC of this embodiment has a wide input and output voltage range, supports a wide input voltage range of 3.5V to 24V, and supports USB 2.0, USB 3.0, USB 3.1 and USB PD input current settings. It can charge 1 to 4 batteries under various input source conditions such as USB adapters, high-voltage USB PD sources and traditional adapters, and is suitable for the power supply system of audio equipment. The BQ25703A battery charging management IC supports OTG function, provides an output voltage of 5V to 20V and programmable current regulation, including output currents of 500mA, 1.5A, 3A and 5A, meeting the USB Type C specification. The BQ25703A battery charging management IC has multiple safety features, including current monitors for input charging power and battery, system power monitors, and thermal shutdown for input power, battery overvoltage protection, and MOSFET and inductor overcurrent protection.

[0056] Specifically, the BQ25703A battery charging management IC used in this embodiment has an input current optimizer (ICO). Through battery algorithm and input current optimization (ICO) technology, it can automatically detect the maximum capacity of the input power to optimize the current while maintaining the consistency of the system and charging current, thereby ensuring that the system obtains the maximum input power and achieves high power efficiency.

[0057] Specifically, in this embodiment, during charging, the charging circuit 40 sets the converter to buck, boost, or buck / boost configuration based on the conditions of the input source and the battery pack 70. The charging circuit 40 automatically switches seamlessly between the buck, boost, and buck / boost configurations without the need for MCU control, so there is no dead zone to ensure efficient conversion between different modes.

[0058] See also Figure 5In the present embodiment, a plurality of battery cell balancing detection circuits are further included, and the plurality of battery cell balancing detection circuits are respectively connected to the plurality of battery cells of the battery pack 70, and are respectively used to detect the balancing state of each of the battery cells, and output the detected balancing state signal to the main control circuit 50, and the main control circuit 50 controls the charging current output by the battery charging management IC according to the balancing state signal.

[0059] Specifically, the present embodiment adopts 4 groups of cell balancing detection circuits with the same circuit structure, which are respectively connected to the positive input terminals of the 4 lithium batteries in the battery pack 70, and are respectively used to access the signals PACK+, C3, C2 and C1. The 4 groups of cell balancing detection circuits all include a number of resistors, capacitors and photoelectric couplers. The above signals are respectively isolated by the photoelectric couplers and then subjected to resistance-capacitance filtering, and the balancing state signals C1 DET, C2 DET, C3 DET and C4 DET are respectively output to the MCU controller.

[0060] Among them, when the main control circuit 50 detects that more than one battery cell has entered the balanced state, in order to avoid misjudgment caused by short-term state jitter, the state of the battery cell is detected again through the battery cell balanced detection circuit after waiting for 30 seconds. If the battery cell is still in the balanced state, the battery charging management IC is configured through the I²C interface to reduce the charging current output by the battery charging management IC from 1.2A to 400mA. At this time, the charging current of the battery cell is the charging current provided by the battery charging management IC minus the shunt of the balanced circuit of the battery cell. This can avoid the current charged into the battery cell being still high, causing the battery cell to be fully charged earlier than other battery cells, so that the battery pack 70 protector shuts down the charging process, while other batteries have not yet reached the full state, causing a large difference in the power of each battery cell.

[0061] Among them, when the main control circuit 50 detects that the balancing state of more than one battery cell has been eliminated, after waiting for 30 seconds, the battery cell is detected again through the battery cell balancing detection circuit. If the battery cell is still in the balancing elimination state, the battery charging management IC is configured through the I²C interface to restore the charging current output by the battery charging management IC to 1.2A.

[0062] See also Figure 6In this embodiment, a battery protection circuit 60 is also included, and the battery protection circuit 60 includes a battery pack protection circuit 63, a plurality of battery cell protection circuits 61 with the same circuit structure as the number of battery cells in the battery pack 70, and a balanced current control circuit 62. The plurality of battery cell protection circuits 61 are connected in series, the positive pole of the power supply of the battery cell protection circuit 61 at the head end is connected to the positive pole of the charging power supply, the negative pole of the power supply of the battery cell protection circuit 61 at the tail end is connected to the negative pole of the charging power supply, and the positive and negative poles of the power supply of the plurality of battery cell protection circuits 61 are respectively connected to the positive and negative ends of the plurality of battery cells. , respectively used to individually control the charge and discharge of each of the battery cells; the battery pack protection circuit 63 is used for voltage, current and temperature protection of the battery pack 70, and has a stackable battery voltage sensing interface for adjusting the battery protection scale according to the number of battery cells in the battery pack 70; the control ends of the multiple balancing current control circuits 62 are respectively connected to the multiple battery voltage sensing interfaces of the battery pack protection circuit 63, and the input and output ends thereof are respectively connected to the positive and negative ends of the multiple battery cells in the battery pack 70, for performing balancing management on each of the battery cells according to the control signal output by the battery pack protection circuit 63.

[0063] In this embodiment, the battery cell protection circuit 61 includes a battery protection IC, a charging FET and a discharging FET. The battery protection IC is provided with a charging control terminal and a discharging control terminal. The battery protection IC is connected to the control terminal of the charging FET through the charging control terminal and is connected to the control terminal of the discharging FET through the discharging control terminal. The input and output terminals of the charging FET and the discharging FET are respectively connected to the positive and negative electrodes of the battery cell, and are respectively used for charging and discharging control of the battery cell.

[0064] Specifically, this embodiment uses 4 battery protection ICs of model BQ29737, 4 groups of charging FETs and discharging FETs. The 4 battery protection ICs are connected in series, and their BATs are all connected to the positive electrode of the lithium battery through a resistor, and their discharge drive pins DOUT are connected to the gate of the discharge FET, and their charging drive pins COUT are connected to the gate of the charging FET. The sources of the 4 discharge FETs are respectively connected to the negative electrodes of the 4 lithium batteries, and the sources of the 4 charging FETs respectively lead to signals C3, C2, C1 and VBAT-signals, and the discharge FETs are all connected to the charging FETs with a common drain.

[0065] Specifically, the charging FET and the discharging FET of this embodiment adopt a 30V common drain, dual N-channel switch device of model CSD87313DMS, which has a low source-to-source on-resistance, can minimize losses, and has a small number of components, which is suitable for space-constrained applications and is suitable for USB Type-C / PD and battery protection in this embodiment.

[0066] In this embodiment, the battery pack protection circuit 63 adopts a stackable low-power battery pack 70 protector model BQ77915, whose stackable interface supports the extended application of a battery pack 70 with multiple battery cells connected in series; it has a variety of configured protection thresholds, provides separate over-temperature and under-temperature thresholds for the discharge and charging of the battery pack 70, and provides an adjustable discharge over-current protection delay; it implements a passive battery balancing algorithm through an integrated FET, so that the battery balancing current of the battery pack 70 can reach up to 50 mA.

[0067] In this embodiment, the balancing current control circuit 62 is an external balancing circuit provided in the battery pack protection circuit 63, which includes a MOSFET and a shunt resistor. The control end of the MOSFET is connected to the battery voltage sensing interface of the battery pack protection circuit 63, and its current input end is connected to the positive electrode of the battery cell through the shunt resistor. The output end is connected to the negative electrode of the battery cell through the input and output ends of the charging FET and the discharging FET. The battery pack protection circuit 63 outputs a control signal to control the MOSFET to turn on, so that the battery balancing current is increased to about 330mA.

[0068] See also Figure 7 In this embodiment, it also includes a power supply output interface 80, which includes the positive and negative poles of the two-pole power supply and the zero-ground voltage output terminal. The power supply output interface 80 is externally connected to a power supply decoupling filter circuit 300, which includes a first electrolytic capacitor, a second electrolytic capacitor, a first bypass capacitor and a second bypass capacitor. The first electrolytic capacitor and the first bypass capacitor are both connected in parallel to the positive pole of the two-pole power supply and the zero-ground voltage output terminal, and are respectively used to filter out high-frequency interference and high-frequency noise from the positive power supply output to the audio circuit 400; the second electrolytic capacitor and the second bypass capacitor are both connected in parallel to the negative pole of the two-pole power supply and the zero-ground voltage output terminal, and are respectively used to filter out high-frequency interference and high-frequency noise from the negative power supply output to the audio circuit 400.

[0069] Among them, the positive power output to the audio circuit 400 includes a bipolar positive power supply of +5.8V to +8.4V and a unipolar positive power supply of +11.6V to +16.8V; the negative power output to the audio circuit 400 includes a bipolar negative power supply of -5.8V to -8.4V and a unipolar 0V power supply.

[0070] Specifically, in this embodiment, the battery direct power supply system 100 based on unipolar charging and bipolar power supply is connected to the power adapter 200 through a USB Type-C interface to input charging power to charge the battery pack, and the discharge power of the power supply system 100 is enhanced and filtered through the power decoupling filter circuit 300 and then output to the audio circuit 400 for power supply.

[0071] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A battery direct power supply system based on unipolar charging and bipolar power supply, comprising a charging input interface, a fast charging protocol control circuit, a charging circuit and a battery pack, characterized in that: It also includes a main control circuit and a power control circuit, wherein the charging input interface is a unipolar charging interface, which is used to connect to an external power adapter to input charging power; The fast charge protocol control circuit performs a connection handshake with the power adapter through the charging input interface to identify the charging protocol, and according to the charging protocol, the power adapter adjusts the voltage and current of the charging power output according to the charging needs of the power receiving end; the input end of the charging circuit is connected to the charging input interface through the power control circuit to input the charging power, and its output end is connected to the battery pack for monitoring the voltage and current of the battery pack, and configuring the charging voltage of the battery pack according to the charging power and battery monitoring data; The charging circuit establishes a communication connection with the main control circuit, and is used to transmit the battery monitoring data to the main control circuit. The main control circuit is used to process and analyze the monitoring data, and output a power control signal to the power control circuit; the power control circuit is used to control the input or cut-off of the charging power supply in the charging circuit according to the power control signal to achieve charging protection; the battery pack adopts a battery series stacking structure, and is used to provide a two-pole power supply with a zero-ground voltage output terminal for the audio circuit; Among them, the battery pack is a series battery pack composed of an even number of pairs of battery cells connected in series, the positive and negative electrodes of the two-pole power supply are respectively led out from the head end and the tail end of the series battery pack, and the neutral-ground voltage output terminal is led out from the common connection end of the two middle battery cells of the series battery pack.

2. The battery direct power supply system based on unipolar charging and bipolar power supply according to claim 1 is characterized in that: The charging input interface adopts a USB Type-C interface. When connected to the power adapter through the USB Type-C interface and powered on, the fast charging protocol control circuit and the power adapter exchange information through an electronic dialogue. The exchanged information includes the fast charging protocol version supported by the receiving end and the maximum accepted current. After the handshake is successful, the power adapter adjusts its output voltage and current according to the charging needs of the receiving end.

3. The battery direct power supply system based on unipolar charging and bipolar power supply according to claim 2 is characterized in that: The fast charging protocol control circuit includes a Type-C receiving end fast charging protocol control chip and its peripheral circuits. The Type-C receiving end fast charging protocol control chip has built-in PD3.1 protocol, PD3.0 / 2.0 protocol, QC3.0 / 2.0 protocol and private fast charging protocol, and is compatible with the 5.0V traditional USB charging protocol, so as to achieve compatibility with multiple external power supplies to provide the charging power.

4. The battery direct power supply system based on unipolar charging and bipolar power supply according to claim 1 is characterized in that: The charging circuit includes a battery charging management IC model BQ25703A and its peripheral circuits. The battery charging management IC has high-precision regulation and monitoring functions, including ±0.5% charging voltage regulation and ±2% input / charging current regulation, which is used to regulate the voltage according to the input charging power supply and the battery pack status and synchronize the battery pack voltage reduction or increase; and has an integrated ADC for monitoring the voltage, current and power of the battery pack.

5. The battery direct power supply system based on unipolar charging and bipolar power supply according to claim 4 is characterized in that: It also includes a plurality of battery cell balancing detection circuits, which are respectively connected to the plurality of battery cells of the battery pack, and are respectively used to detect the balancing state of each battery cell, and output the detected balancing state signal to the main control circuit, and the main control circuit controls the charging current output by the battery charging management IC according to the balancing state signal; When the main control circuit detects that one or more battery cells have entered a balanced state, the battery cell is detected again through the battery cell balanced detection circuit after waiting for 30 seconds. If the battery cell is still in a balanced state, the battery charging management IC is configured through the I²C interface to reduce the charging current output by the battery charging management IC from 1.2A to 400mA. Among them, when the main control circuit detects that the balancing state of more than one battery cell has been eliminated, the battery cell is detected again through the battery cell balancing detection circuit after waiting for 30 seconds. If the battery cell is still in the balancing elimination state, the battery charging management IC is configured through the I²C interface to restore the charging current output by the battery charging management IC to 1.2A.

6. The battery direct power supply system based on unipolar charging and bipolar power supply according to claim 1, characterized in that: It also includes a battery protection circuit, which includes a battery pack protection circuit, a plurality of battery cell protection circuits with the same circuit structure as the number of battery cells in the battery pack, and a balanced current control circuit. The plurality of battery cell protection circuits are connected in series, the positive pole of the power supply of the battery cell protection circuit at the head end is connected to the positive pole of the charging power supply, the negative pole of the power supply of the battery cell protection circuit at the tail end is connected to the negative pole of the charging power supply, and the positive and negative poles of the power supply of the plurality of battery cell protection circuits are respectively connected to the positive and negative ends of the plurality of battery cells, and are respectively used to individually control the charging and discharging of each of the battery cells; The battery pack protection circuit is used for voltage, current and temperature protection of the battery pack, and has a stackable battery voltage sensing interface for adjusting the battery protection scale according to the number of battery cells in the battery pack; The control ends of the multiple balancing current control circuits are respectively connected to the multiple battery voltage sensing interfaces of the battery pack protection circuit, and their input and output ends are respectively connected to the positive and negative ends of the multiple battery cells in the battery pack, so as to perform balancing management on each of the battery cells according to the control signal output by the battery pack protection circuit.

7. The battery direct power supply system based on unipolar charging and bipolar power supply according to claim 6, characterized in that: The battery cell protection circuit includes a battery protection IC, a charging FET and a discharging FET. The battery protection IC is provided with a charging control terminal and a discharging control terminal. The battery protection IC is connected to the control terminal of the charging FET through the charging control terminal and is connected to the control terminal of the discharging FET through the discharging control terminal. The input and output terminals of the charging FET and the discharging FET are respectively connected to the positive and negative electrodes of the battery cell, and are respectively used for charging and discharging control of the battery cell.

8. The battery direct power supply system based on unipolar charging and bipolar power supply according to claim 7 is characterized in that: The battery pack protection circuit adopts a stackable low-power battery pack protector model BQ77915, whose stackable interface supports the extended application of multi-battery unit series battery packs; it has a variety of configured protection thresholds, provides separate over-temperature and under-temperature thresholds for the discharge and charge of the battery pack and provides an adjustable discharge over-current protection delay; it implements a passive battery balancing algorithm through an integrated FET, so that the battery balancing current of the battery pack can reach up to 50 mA.

9. The battery direct power supply system based on unipolar charging and bipolar power supply according to claim 8, characterized in that: The balancing current control circuit is an external balancing circuit provided in the battery pack protection circuit, which includes a MOSFET and a shunt resistor. The control end of the MOSFET is connected to the battery voltage sensing interface of the battery pack protection circuit, its current input end is connected to the positive electrode of the battery cell through the shunt resistor, and its output end is connected to the negative electrode of the battery cell through the input and output ends of the charging FET and the discharging FET. The MOSFET is controlled to be turned on by the battery pack protection circuit outputting a control signal, so that the battery balancing current is increased to about 330mA.

10. The battery direct power supply system based on unipolar charging and bipolar power supply according to any one of claims 1 to 9, characterized in that: It also includes a power supply output interface, the power supply output interface includes the positive and negative poles of the two-pole power supply and the zero-ground voltage output end, the power supply output interface is externally connected to a power supply decoupling filter circuit, the power supply decoupling filter circuit includes a first electrolytic capacitor, a second electrolytic capacitor, a first bypass capacitor and a second bypass capacitor, the first electrolytic capacitor and the first bypass capacitor are both connected in parallel to the positive pole of the two-pole power supply and the zero-ground voltage output end, and are respectively used to filter out high-frequency interference and high-frequency noise from the positive power supply output to the audio circuit; the second electrolytic capacitor and the second bypass capacitor are both connected in parallel to the negative pole of the two-pole power supply and the zero-ground voltage output end, and are respectively used to filter out high-frequency interference and high-frequency noise from the negative power supply output to the audio circuit; Among them, the positive power supply output to the audio circuit includes a bipolar positive power supply of +5.8V to +8.4V and a unipolar positive power supply of +11.6V to +16.8V; the negative power supply output to the audio circuit includes a bipolar negative power supply of -5.8V to -8.4V and a unipolar 0V power supply; The power source output from the neutral voltage output terminal to the audio circuit is a bipolar 0V center reference voltage.

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