Biphase buck switch charger with battery charging and system power supply path management functions

Abstract

The invention relates to a double-phase buck switch charger with battery charging and system power supply path management functions, and belongs to the technical field of electronics. According to the double-phase buck switch charger, the switch control and current detection module controls the switch device to be turned on, the battery is connected to the system to achieve system power supply path management, the double-phase buck circuit is adopted, and the switch control and current detection module is used for detecting the states of the battery voltage and the power supply voltage. The dual-phase buck circuit is controlled to be switched between a buck charging mode and a boost discharging mode to realize battery charging management, and meanwhile, the dual-phase buck circuit enables the inductance charging time proportion in a full period to be close to 100%, so that the output power is greatly improved; a charge pump fast charging circuit, a Buck charging circuit and a battery charging management and system power supply path management circuit can be effectively replaced, the charging and discharging system is simplified, the PCB space is saved, and the overall device cost is reduced.

Description

Technical Field

[0001] The invention relates to the field of electronic technology, and in particular to a dual-phase buck switch charger with battery charging and system power path management. Background Art

[0002] With the rapid development of integrated circuits and Internet of Things technologies, the functions of consumer electronic products are becoming increasingly powerful, and their application scenarios are constantly expanding. They are gradually becoming indispensable necessities for people's daily life, office, and entertainment. Portable electronic devices such as smart phones, smart watches, smart bracelets, TWS headphones, etc. have become a part of our lives.

[0003] Adequate power supply can fully utilize the performance of electronic devices and provide users with the best experience. However, the higher the intelligence of portable devices, the more functions they have, and the more frequently they are used, the greater their energy consumption becomes, which will seriously shorten the battery life of electronic devices.

[0004] In order to meet people's daily convenience, so that users don't have to carry bulky power banks when going out, and get rid of power anxiety, today's portable devices are designed with low-power chips to reduce system power consumption on the one hand, and the capacity of built-in batteries is continuously increased to increase battery life on the other hand. At present, ultra-long battery life or ultra-long standby has become a hot selling point for consumer electronic products. However, as the battery capacity increases, the traditional 5V / 1A or 5V / 2A power supply can no longer fully charge the battery in a short time. In order to reduce the time cost spent by users on charging, high-power and high-current fast charging solutions were born.

[0005] Currently, the fast charging products on the market are mainly charge pump step-down solutions, and the charge pump fast charging circuit is only responsible for high-current charging. The Buck circuit is also required to be responsible for trickle charging, pre-charging and constant-voltage charging processes, as well as battery charging management and system power path management circuits. The system is relatively complex and costly.

[0006] How to propose a charger with battery charging management and system power path management that can effectively replace the charge pump fast charging circuit, Buck charging circuit, and battery charging management and system power path management circuit has become an urgent problem to be solved in this field. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a dual-phase buck switch charger with battery charging management and system power path management, which can effectively replace the charge pump fast charging circuit, Buck charging circuit and battery charging management and system power path management circuit, simplify the system and reduce costs.

[0008] In order to achieve the above-mentioned purpose, the dual-phase buck switch charger with battery charging and system power path management of the present invention has the following structure:

[0009] The dual-phase buck switch charger with battery charging and system power path management adopts a low voltage dropout VDC architecture and separates the system from the battery through a switch device 1010;

[0010] When the voltage of the connected battery is higher than the exhaustion threshold, the switch control and current detection module 1009 controls the switch device 1010 to open and connect the battery to the system;

[0011] The two-phase buck circuit is connected to an input power supply voltage VAC and an output voltage Vout, and the two-phase buck circuit includes a first high-side switch 1014, a second high-side switch 1013, a first low-side switch 1011 and a second low-side switch 1012;

[0012] The control switch control module and the interrupt control module 1002 are connected to the gates of the first high side switch 1014, the second high side switch 1013, the first low side switch 1011 and the second low side switch 1012;

[0013] The drains of the first high-side switch 1014 and the second high-side switch 1013 are both connected to the bus voltage VBUS; the source of the first high-side switch 1014 is connected to the drain of the first low-side switch 1011 and is connected to the output voltage Vout terminal through the first inductor L1; the source of the second high-side switch 1013 is connected to the drain of the second low-side switch 1012 and is connected to the output voltage Vout terminal through the second inductor L2; the first low-side switch 1011 and the second low-side switch 1012 are grounded;

[0014] When the input power supply voltage VAC is higher than the startup threshold and lower than the overvoltage threshold, the bus voltage VBUS is powered on;

[0015] When the switch control and current detection module 1009 detects that the battery voltage is lower than the power supply voltage VAC, the dual-phase buck circuit is controlled to operate in the step-down charging mode through the control switch control module and the interrupt control module 1002; in the first half cycle, the first high-side switch 1014 and the second low-side switch 1012 are turned on at the same time, the second high-side switch 1013 and the first low-side switch 1011 are turned off at the same time, the first inductor L1 is charged through the first high-side switch 1014, and the second inductor L2 is discharged through the second low-side switch 1012; in the second half cycle, the second high-side switch 1013 and the first low-side switch 1011 are turned on at the same time, the first high-side switch 1014 and the second low-side switch 1012 are turned off at the same time, the second inductor L2 is charged through the second high-side switch 1013, and the first inductor L1 is discharged through the first low-side switch 1011; during the inductor charging process, the inductor is connected in series with the battery to play a role of voltage division, and during the inductor discharging process, the inductor is connected in parallel with the battery, and the inductor voltage is equal to the battery voltage;

[0016] When the switch control and current detection module 1009 detects that the battery voltage is higher than the battery undervoltage threshold, the dual-phase buck circuit is controlled to operate in a boost discharge mode through the control switch control module and the interrupt control module 1002; in the first half cycle, the battery charges the first inductor L1, the first low-side switch 1011 is turned on, the second inductor L2 is connected in series with the battery, and discharges to the load through the second high-side switch 1013; in the second half cycle, the first inductor L1 is connected in series with the battery, and discharges to the load through the first high-side switch 1014; the second low-side switch 1012 is turned on, and the battery charges the second inductor L2.

[0017] In the dual-phase buck switch charger with battery charging and system power path management, the conditions for the control switch control module and the interrupt control module 1002 to control the dual-phase buck circuit to operate in the boost discharge mode are specifically:

[0018] The switch control and current detection module 1009 detects that the battery voltage is higher than the battery undervoltage threshold, and the power supply voltage VAC is lower than the battery voltage with a certain voltage difference, and the battery temperature monitoring module 1007 does not detect abnormal battery temperature.

[0019] The dual-phase buck switch charger with battery charging and system power path management also includes: a battery voltage / current detection module 1008, which is used to detect the battery voltage and battery current. When the battery is completely exhausted, the system adjusts the system voltage to above the minimum system voltage according to the minimum system voltage set in the register of the reference voltage module 1006.

[0020] In the dual-phase buck switch charger with battery charging and system power path management, when the dual-phase buck circuit operates in the buck charging mode, the switch control and current detection module 1009 detects the charging current in real time. When the charging current drops to zero but the input source is still overloaded, the system voltage starts to drop through the control switch control module and the interrupt control module 1002. When the system voltage is lower than the battery voltage, the switch control and current detection module 1009 controls the switch device 1010 to turn on, and the battery starts to discharge.

[0021] In the dual-phase buck switch charger with battery charging and system power path management, when the system voltage is lower than the battery voltage and the battery discharge current is low, the switch control and current detection module 1009 controls the minimum drain-source voltage V of the switch device 1010 DS Maintained at 30mv, as the discharge current increases, the switch device 1010 adopts a higher gate-source voltage V GS voltage to reduce the on-state resistance R DS (ON) until the switch device 1010 is fully turned on.

[0022] In the dual-phase buck switch charger with battery charging and system power path management, the switch control and current detection module 1009 monitors the discharge current of the battery through the switch device 1010. When the discharge current of the battery is greater than the discharge overcurrent protection current threshold, the switch device 1010 is turned off through the switch control and current detection module 1009, and the abnormal signal is transmitted to the protection module 1004 and the corresponding control register bit of the digital logic and communication module 1003 is set to be disabled. The switch control module and the interrupt control module 1002 also control the interrupt and status output module 1005 to output an interrupt signal and notify the host.

[0023] In the dual-phase buck switch charger with battery charging and system power path management, the protection module 1004 reports various interrupt events to the host at the interrupt port through the interrupt and status output module 1005, including: identification of type-c or adapter source; detection of a good input source; VBUS is higher than the battery voltage; VAC, VBUS are lower than the overvoltage threshold; VBUS is higher than the minimum operating voltage of VBUS and the load capacity is greater than 30mA; input source removed; charging completed; battery connected; battery removed.

[0024] In the dual-phase buck switch charger with battery charging and system power path management, when the input power supply voltage VAC is higher than the startup threshold and lower than the overvoltage threshold, the bus voltage VBUS is powered on, the LDO linear power supply module 1001 is enabled to provide bias power for the internal bias circuit, and gate drive is provided for the first high-side switch 1014, the second high-side switch 1013, the first low-side switch 1011 and the second low-side switch 1012 through the control switch control module and the interrupt control module 1002.

[0025] In the dual-phase buck switch charger with battery charging and system power path management, the input current limit setting is changed by modifying the register by the host. After the input current limit is set, the switch control module and the interrupt control module 1002 are controlled by setting the corresponding control register of the digital logic and communication module 1003 to enable the working mode switching of the dual-phase buck circuit, switching between the buck charging mode and the boost discharging mode.

[0026] In the dual-phase buck switch charger with battery charging and system power path management, when the dual-phase buck circuit is controlled by the switch control module and the interrupt control module 1002 to enable battery charging, a charging cycle is automatically completed. The charging cycle includes constant current mode trickle charging, constant current mode pre-charging, constant current high current charging, and constant voltage charging. When the battery voltage is higher than the charging threshold and the battery current is lower than the termination current, the switch control module and the interrupt control module 1002 control the termination of the charging cycle and turn off the switch device 1010.

[0027] The invention adopts a dual-phase buck switch charger with battery charging and system power path management, which controls the switch device to open and connect the battery to the system through a switch control and current detection module to achieve system power path management. A dual-phase buck circuit is adopted, and the switch control and current detection module is used to detect the status of the battery voltage and the power supply voltage, and the dual-phase buck circuit is controlled to switch between the buck charging mode and the boost discharge mode to achieve battery charging management. At the same time, the dual-phase buck circuit makes the inductor charging time account for nearly 100% of the full cycle, greatly improving the output power. It can effectively replace the charge pump fast charging circuit, the Buck charging circuit, and the battery charging management and system power path management circuits, simplify the charging and discharging system, save PCB space, and reduce the overall device cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The schematic diagram and external wiring diagram of the dual-phase buck switch charger with battery charging and system power path management of the present invention are shown.

[0029] Figure 2It is a schematic diagram of VAC power-on and overvoltage protection of the present invention.

[0030] Figure 3 It is a current path diagram of the present invention under the buck charging mode.

[0031] Figure 4 It is a schematic diagram of the inductor current and output current waveforms under the buck charging mode of the present invention.

[0032] Figure 5 It is a current path diagram of the present invention under the boost discharge mode operation.

[0033] Figure 6 It is a schematic diagram of the inductor current and output current waveforms under the boost discharge mode of the present invention.

[0034] Figure 7 Schematic diagram of the high-side / low-side switch startup waveform of the present invention.

[0035] Figure 8 It is a schematic diagram of the charging curve under the buck charging mode of the present invention. DETAILED DESCRIPTION

[0036] In order to more clearly understand the technical content of the present invention, the following embodiments are given in detail.

[0037] See also Figure 1 As shown, it is a principle block diagram and external wiring diagram of the dual-phase buck switch charger with battery charging and system power path management of the present invention.

[0038] In one embodiment, the dual-phase buck switch charger with battery charging and system power path management adopts a low voltage dropout VDC architecture to separate the system from the battery through a switch device 1010;

[0039] When the voltage of the connected battery is higher than the exhaustion threshold, the switch control and current detection module 1009 controls the switch device 1010 to open and connect the battery to the system;

[0040] The two-phase buck circuit is connected to an input power supply voltage VAC and an output voltage Vout, and the two-phase buck circuit includes a first high-side switch 1014, a second high-side switch 1013, a first low-side switch 1011 and a second low-side switch 1012;

[0041] The control switch control module and the interrupt control module 1002 are connected to the gates of the first high side switch 1014, the second high side switch 1013, the first low side switch 1011 and the second low side switch 1012;

[0042] like Figure 1 , 3As shown in , 5, the drains of the first high side switch 1014 and the second high side switch 1013 are both connected to the bus voltage VBUS; the source of the first high side switch 1014 is connected to the drain of the first low side switch 1011 and is connected to the output voltage Vout terminal through the first inductor L1; the source of the second high side switch 1013 is connected to the drain of the second low side switch 1012 and is connected to the output voltage Vout terminal through the second inductor L2; the first low side switch 1011 and the second low side switch 1012 are grounded;

[0043] When the input power supply voltage VAC is higher than the startup threshold and lower than the overvoltage threshold, the bus voltage VBUS is powered on, such as Figure 2 As shown;

[0044] When the switch control and current detection module 1009 detects that the battery voltage is lower than the power supply voltage VAC, the dual-phase buck circuit is controlled to operate in a step-down charging mode through the control switch control module and the interrupt control module 1002; Figure 3 As shown, the left side is the current path diagram for the first half cycle, and the back side is the current path diagram for the second half cycle. In the first half cycle, the first high side switch 1014 and the second low side switch 1012 are turned on at the same time, the second high side switch 1013 and the first low side switch 1011 are turned off at the same time, the first inductor L1 is charged through the first high side switch 1014, and the second inductor L2 is discharged through the second low side switch 1012; in the second half cycle, the second high side switch 1013 and the first low side switch 1011 are turned on at the same time, the first high side switch 1014 and the second low side switch 1012 are turned off at the same time, the second inductor L2 is charged through the second high side switch 1013, and the first inductor L1 is discharged through the first low side switch 1011; Figure 3 The middle dotted line is the current path of the buck charging mode. During the inductor charging process, the inductor and the battery are connected in series to play a role of voltage division. During the inductor discharging process, the inductor and the battery are connected in parallel, and the inductor voltage is equal to the battery voltage. The inductor current and output current waveforms under the buck charging mode are as follows: Figure 4 shown.

[0045] When the switch control and current detection module 1009 detects that the battery voltage is higher than the battery undervoltage threshold, and the power supply voltage VAC is lower than the battery voltage and has a certain voltage difference, and the battery temperature monitoring module 1007 does not detect abnormal battery temperature, the dual-phase buck circuit is controlled to operate in the boost discharge mode through the control switch control module and the interrupt control module 1002; Figure 5As shown, the left side is the current path diagram for the first half cycle, and the back side is the current path diagram for the second half cycle. In the first half cycle, the battery charges the first inductor L1, the first low-side switch 1011 is turned on, the second inductor L2 is connected in series with the battery, and discharges to the load through the second high-side switch 1013; in the second half cycle, the first inductor L1 is connected in series with the battery, and discharges to the load through the first high-side switch 1014; the second low-side switch 1012 is turned on, and the battery charges the second inductor L2. Figure 5 The dotted line in the middle is the current path of the boost discharge mode. The inductor current and output current waveforms under the boost discharge mode are as follows: Figure 6 shown.

[0046] In a preferred embodiment, the dual-phase buck switching charger with battery charging and system power path management is as follows: Figure 1 As shown, it also includes: a battery voltage / current detection module 1008, which is used to detect the battery voltage and battery current. When the battery is completely exhausted, the system adjusts the system voltage to above the minimum system voltage according to the minimum system voltage set in the register of the reference voltage module 1006.

[0047] In a further preferred embodiment, Figure 1 As shown, when the two-phase buck circuit operates in the step-down charging mode, the switch control and current detection module 1009 detects the charging current in real time. When the charging current drops to zero but the input source is still overloaded, the system voltage starts to drop through the control switch control module and the interrupt control module 1002; when the system voltage is lower than the battery voltage, the switch control and current detection module 1009 controls the switch device 1010 to turn on, and the battery starts to discharge.

[0048] In a further preferred embodiment, when the system voltage is lower than the battery voltage and the battery discharge current is low, the switch control and current detection module 1009 controls the minimum drain-source voltage V of the switch device 1010. DS Maintained at 30mv, as the discharge current increases, the switch device 1010 adopts a higher gate-source voltage V GS voltage to reduce the on-state resistance R DS (ON) until the switch device 1010 is fully turned on.

[0049] In another preferred embodiment, the switch control and current detection module 1009 monitors the discharge current of the battery through the switch device 1010. When the discharge current of the battery is greater than the discharge overcurrent protection current threshold, the switch device 1010 is closed by the switch control and current detection module 1009, and the abnormal signal is transmitted to the protection module 1004 and the corresponding control register bit of the digital logic and communication module 1003 is set to be disabled. The switch control module and the interrupt control module 1002 also control the interrupt and status output module 1005 to output an interrupt signal and notify the host.

[0050] In another further preferred embodiment, the protection module 1004 reports multiple interrupt events to the host at the interrupt port through the interrupt and status output module 1005, including: identifying type-c or adapter source; detecting a good input source; VBUS is higher than the battery voltage; VAC, VBUS are lower than the overvoltage threshold; VBUS is higher than the minimum operating voltage of VBUS and the load capacity is greater than 30mA; input source is removed; charging is completed; battery is connected; battery is removed.

[0051] In a preferred embodiment, when the input power supply voltage VAC is higher than the startup threshold and lower than the overvoltage threshold, the bus voltage VBUS is powered on, the LDO linear power supply module 1001 is enabled, and a bias power supply is provided for the internal bias circuit, and gate drive is provided for the first high-side switch 1014, the second high-side switch 1013, the first low-side switch 1011, and the second low-side switch 1012 through the control switch control module and the interrupt control module 1002.

[0052] In another preferred embodiment, the input current limit setting is changed by modifying the register by the host. After the input current limit is set, the corresponding control register of the digital logic and communication module 1003 is set to control the switch control module and the interrupt control module 1002 to enable the working mode switching of the two-phase buck circuit, switching between the step-down charging mode and the boost discharge mode.

[0053] In a more preferred embodiment, when the dual-phase buck circuit is controlled by the switch control module and the interrupt control module 1002 to enable battery charging, a charging cycle is automatically completed, and the charging cycle includes constant current mode trickle charging, constant current mode pre-charging, constant current high current charging, and constant voltage charging. When the battery voltage is higher than the charging threshold and the battery current is lower than the termination current, the switch control module and the interrupt control module 1002 control the termination of the charging cycle and turn off the switch device 1010.

[0054] In practical applications, the principle block diagram and external wiring of the dual-phase buck switch charger with battery charging and system power path management of the present invention are as follows: Figure 1 As shown. The internal bias circuit is powered by the higher voltage of VAC and BAT. When VAC or BAT is above the startup threshold, the sleep comparator, battery depletion comparator and switch device 1010 are enabled. The I2C interface is ready for communication and all registers are reset to default values. The host can access all registers after a power-on reset. If only the battery is present and the voltage is above the depletion threshold, the switch control and current detection module 1009 controls the switch device 1010 to turn on and connect the battery to the system. The REGN LDO module 1001 remains off and the system operates with minimized quiescent current to maximize battery runtime. The device always monitors the discharge current through the switch device 1010. When the system is overloaded or short-circuited (battery discharge current is greater than the discharge overcurrent protection current threshold), the device immediately turns off the switch device 1010 through the switch control and current detection module 1009, transmits the abnormal signal to the protection module 1004 and sets the corresponding control register bit of the digital logic and communication module 1003 to disable, and then controls the interrupt and status output module 1005 to output an interrupt signal through the switch control module and interrupt control module 1002 to notify the host. Until the input source is inserted again, the reset circuit or the register controls the switch control and current detection module 1009 to re-enable the switch device 1010.

[0055] like Figure 2 As shown in Figure 1, when VAC is higher than the startup threshold and lower than the overvoltage threshold, VGATE is high, the external MOS Q1 is turned on, and VBUS is powered on. Figure 1 Content, LDO linear power supply module 1001 is enabled, REGN port outputs high level; internal anti-backflow MOS Q2 is turned on, PMID output voltage is approximately VBUS voltage; REGN LDO provides bias power for internal bias circuit, and is the first high-side switch 1014 ( Figure 1 , 3 , 5, 7 marked "high side switch 1"), the second high side switch 1013 ( Figure 1 , 3 , 5, 7 marked "high side switch 2)", the first low side switch 1011 ( Figure 1 , 3 , 5, 7 marked "low side switch 1"), the second low side switch 1012 ( Figure 1 , 3 , 5, and 7) provide gate drive. The LDO linear power module 1001 also provides bias voltage for the external TS resistor. The pull-up resistors of STAT and PG can also be connected to the REGN terminal. When VAC is higher than the overvoltage threshold, VGATE is low, the external MOS Q1 is turned off, and VBUS is powered off.

[0056] like Figure 1As shown, after the LDO linear power module 1001 at the REGN end is enabled, the device detects the current capability of the input source. The VBUS voltage must be lower than the overvoltage point and higher than the minimum operating voltage. The load capacity is greater than 30mA. The PG port is set low, otherwise the PG port and the status register will be set high, and the INT interrupt pin will send a pulse signal to the host. If the power capability detection fails, the power capability detection is repeated every 2 seconds.

[0057] like Figure 1 As shown, the device follows the Type-C / USB battery charging specification and detects input sources (SDP / CDP / DCP) and non-standard adapters through CC1 / DP, CC2 / DM lines. In addition, when DCP is detected, it starts an adjustable high-voltage adapter handshake on CC1 / DP, CC2 / DM. The detection result is output by the PSEL port, high for USB source, and low for adapter source.

[0058] like Figure 1 As shown in Figure 1, the host can modify the IINLIM register to change the input current limit if necessary. The charger input current is always limited to the lower value of the IINLIM register or the ILIM pin.

[0059] like Figure 1 As shown, after VBUS and VBAT meet the step-down conversion conditions and the input current limit setting is completed, the corresponding control register of the digital logic and communication module 1003 can be set to control the switch control module and the interrupt control module 1002 to control the converter to enable, and the first high-side switch 1014, the second high-side switch 1013, the first low-side switch 1011, and the second low-side switch 1012 start switching. If battery charging is disabled, the switch device 1010 is turned off. Otherwise, the switch device 1010 will continue to charge the battery. Figure 3 and Figure 7 As shown, this circuit structure is different from the traditional single-channel Buck circuit (only a single charging and discharging process in a switching cycle). The first high-side switch 3001 and the second low-side switch 3004 are turned on at the same time (driving waveform high level). In the first half of the cycle, the inductor L1 is charged through the first high-side switch 1014, and L2 is discharged through the second low-side switch 1012. In the second half of the cycle, L2 is charged through the second high-side switch 1013, and L1 is discharged through the first low-side switch 1011. During the inductor charging process, the inductor and the battery are connected in series to play a voltage divider role. During the inductor discharging process, the inductor and the battery are connected in parallel, and the inductor voltage is equal to the battery voltage. The inductor charging time accounts for nearly 100% of the full cycle, which greatly improves the output power. As shown Figure 4 As shown, the total output current 4003 offsets the ripple current due to the complementary effect of the L1 inductor current 4001 and the L2 inductor current 4002, thereby greatly reducing the ripple voltage of VOUT (even in the state without output capacitor).

[0060] like Figure 1 As shown, this device supports boost conversion. When the battery voltage is higher than the battery undervoltage threshold, the VAC voltage is lower than a certain voltage difference of BAT, and the battery temperature monitoring module 1007 does not detect abnormal battery temperature, the converter can be controlled to work in boost mode through the OTG port and the corresponding boost enable bit of the digital logic communication module 1003, and the battery power can be transmitted from the VAC port to other portable devices. Figure 5 and Figure 7 As shown, this circuit structure is different from the traditional single-channel Boost circuit (only a single charging and discharging process in a switching cycle). In a boost working cycle, the battery charges L1 in the first half of the cycle, the first low-side switch 5002 is turned on, and the L2 series battery VBAT discharges to the load through the second high-side switch 5003; in the second half of the cycle, the fully charged L1 series battery VBAT discharges to the load through the first high-side switch 5005, the second low-side switch 5008 is turned on, and L2 is recharged. The inductor charging time accounts for nearly 100% of the full cycle, which greatly improves the output power. Figure 6 As shown, the total output current 6003 also offsets the ripple current due to the complementary effect of the L1 inductor current 6001 and the L2 inductor current 6002, greatly reducing the ripple voltage of VOUT (even in the absence of output capacitors). Figure 6 As shown, the current flowing out of the battery is defined as a negative value, I L1 ,I L2 ,I LOAD The current is negative.

[0061] like Figure 1 , Figure 7 As shown, Figure 7 The schematic diagram of the high-side / low-side switch startup waveform of the present invention shows that the left side is the buck mode and the right side is the boost mode. The device strictly controls the conduction interval time (dead time) of the first high-side switch 1014, the second high-side switch 1013, the first low-side switch 1011, and the second low-side switch 1012. The first high-side switch 1014, the first low-side switch 1011, (or the second high-side switch 1013, the second low-side switch 1012) are not turned on at the same time, which increases the efficiency and prevents the occurrence of a power supply short circuit to the ground.

[0062] like Figure 1As shown, this device uses a low dropout VDC architecture and uses a switch device 1010 to separate the system from the battery. The minimum system voltage is set by a register. Even if the battery is completely exhausted, the system will be regulated above the minimum system voltage (3.5V by default). When the battery is lower than the minimum system voltage setting value, the switch device 1010 operates in linear mode (LDO mode) and the system is regulated above the minimum system voltage setting value. When the battery voltage is higher than the minimum system voltage, the switch device 1010 is fully turned on, and the voltage difference between the system and the battery is the VDS of the switch device 1010.

[0063] like Figure 1 , Figure 8 As shown, when the charging current drops to zero but the input source is still overloaded, the system voltage begins to drop. When the system voltage is lower than the battery voltage, the device automatically enters the supplementary discharge mode, the switching device 1010 is turned on, the battery begins to discharge, and the system is powered by the input power and the battery at the same time. When the system voltage is lower than the battery voltage, the switching device 1010 is turned on, and the driving of the switching device 1010 is adjusted so that the minimum VDS of the switching device 1010 is maintained at 30mv when the current is low. This prevents oscillation from occurring. As the discharge current increases, the switching device 1010 is adjusted with a higher voltage to reduce the RDS(ON) until the switching device 1010 is fully turned on.

[0064] like Figure 8 As shown, after battery charging is enabled, the device automatically completes a charging cycle, including constant current mode trickle charging, constant current mode pre-charging, constant current high current charging, and constant voltage charging, without the need for host participation. The host can write to the corresponding registers through I2C to control the charging operation at any time and optimize the charging parameters. When the battery voltage is higher than the charging threshold and the current is lower than the termination current, the device terminates the charging cycle. After the charging cycle is completed, the switching device 1010 is turned off. When termination occurs, the status register is set and INT sends an interrupt pulse signal to the host.

[0065] like Figure 1 As shown, the device continuously monitors the battery temperature by measuring the voltage between the TS pin and ground, which is usually determined by a negative temperature coefficient thermistor (NTC) and an external voltage divider. The device compares this voltage with its internal threshold to determine whether charging is allowed. To initiate a charge cycle, the voltage on the TS pin must be within the threshold range of VT1 to VT5. When the TS voltage exceeds the T1-T5 range, the controller suspends charging and waits for the battery temperature to return to the T1-T5 range.

[0066] like Figure 1 As shown, the protection module 1004 can report various interrupt events to the host through the interrupt and status output module 1005 at the INT interrupt port. For example:

[0067] Identify the type-c / adapter source (via PSEL or CC1 / DP, CC2 / DM detection);

[0068] A good input source is detected;

[0069] –VBUS is higher than the battery voltage;

[0070] –VAC, VBUS are lower than the overvoltage threshold;

[0071] –VBUS is higher than the minimum VBUS operating voltage and the load capacity is greater than 30mA;

[0072] Input source removal;

[0073] Charging is complete;

[0074] Battery access;

[0075] Battery removal;

[0076] Any exception event in the interrupt register.

[0077] like Figure 1 As shown, in order to extend the battery life, when the system is powered off during system idleness, transportation or storage, the device can turn off the switch device 1010 to make the system voltage zero to minimize battery leakage current. When the power cable is plugged in again, the switch control and current detection module 1009 re-enables the switch device 1010, resets the entire system, or the logic high to low transition on the QON pin occurs, the switch device 1010 exits the shipping mode.

[0078] The invention adopts a dual-phase buck switch charger with battery charging and system power path management, which controls the switch device to open and connect the battery to the system through a switch control and current detection module to achieve system power path management. A dual-phase buck circuit is adopted, and the switch control and current detection module is used to detect the status of the battery voltage and the power supply voltage, and the dual-phase buck circuit is controlled to switch between the buck charging mode and the boost discharge mode to achieve battery charging management. At the same time, the dual-phase buck circuit makes the inductor charging time account for nearly 100% of the full cycle, greatly improving the output power. It can effectively replace the charge pump fast charging circuit, the Buck charging circuit, and the battery charging management and system power path management circuits, simplify the charging and discharging system, save PCB space, and reduce the overall device cost.

[0079] In this specification, the present invention has been described with reference to specific embodiments thereof. However, it is apparent that various modifications and variations may be made without departing from the spirit and scope of the present invention. Therefore, the specification and drawings should be regarded as illustrative rather than restrictive.

Claims

1. A dual-phase buck switching charger with battery charging and system power path management, characterized in that: A low voltage drop VDC architecture is adopted to separate the system from the battery through a switch device (1010); When the voltage of the connected battery is higher than the exhaustion threshold, the switch control and current detection module (1009) controls the switch device (1010) to open and connect the battery to the system; The two-phase buck circuit is connected to an input power supply voltage VAC and an output voltage Vout, and comprises a first high-side switch (1014), a second high-side switch (1013), a first low-side switch (1011) and a second low-side switch (1012); The switch control module and the interrupt control module (1002) are controlled to connect the gates of the first high side switch (1014), the second high side switch (1013), the first low side switch (1011) and the second low side switch (1012); The drains of the first high-side switch (1014) and the second high-side switch (1013) are both connected to the bus voltage VBUS; the source of the first high-side switch (1014) is connected to the drain of the first low-side switch (1011) and is connected to the output voltage Vout terminal through the first inductor L1; the source of the second high-side switch (1013) is connected to the drain of the second low-side switch (1012) and is connected to the output voltage Vout terminal through the second inductor L2; the first low-side switch (1011) and the second low-side switch (1012) are grounded; When the input power supply voltage VAC is higher than the startup threshold and lower than the overvoltage threshold, the bus voltage VBUS is powered on; When the switch control and current detection module (1009) detects that the battery voltage is lower than the power supply voltage VAC, the switch control module and the interrupt control module (1002) are used to control the dual-phase buck circuit to operate in a step-down charging mode; in the first half cycle, the first high-side switch (1014) and the second low-side switch (1012) are turned on simultaneously, the second high-side switch (1013) and the first low-side switch (1011) are turned off simultaneously, the first inductor L1 is charged through the first high-side switch (1014), and the second high-side switch (1013) and the first low-side switch (1011) are turned off simultaneously. The inductor L2 is discharged through the second low-side switch (1012); in the second half cycle, the second high-side switch (1013) and the first low-side switch (1011) are switched on at the same time, and the first high-side switch (1014) and the second low-side switch (1012) are switched off at the same time, the second inductor L2 is charged through the second high-side switch (1013), and the first inductor L1 is discharged through the first low-side switch (1011); during the inductor charging process, the inductor is connected in series with the battery to play a role of voltage division, and during the inductor discharging process, the inductor is connected in parallel with the battery, and the inductor voltage is equal to the battery voltage; When the switch control and current detection module (1009) detects that the battery voltage is higher than the battery undervoltage threshold, the switch control module and the interrupt control module (1002) are used to control the dual-phase buck circuit to operate in a boost discharge mode; in the first half cycle, the battery charges the first inductor L1, the first low-side switch (1011) is turned on, the second inductor L2 is connected in series with the battery, and discharges to the load through the second high-side switch (1013); in the second half cycle, the first inductor L1 is connected in series with the battery, and discharges to the load through the first high-side switch (1014); the second low-side switch (1012) is turned on, and the battery charges the second inductor L2.

2. The dual-phase buck switching charger with battery charging and system power path management according to claim 1, characterized in that: The conditions under which the control switch control module and the interrupt control module (1002) control the dual-phase buck circuit to operate in the boost discharge mode are specifically: The switch control and current detection module (1009) detects that the battery voltage is higher than the battery undervoltage threshold, and the power supply voltage VAC is lower than the battery voltage and has a certain voltage difference, while the battery temperature monitoring module (1007) does not detect abnormal battery temperature.

3. The dual-phase buck switching charger with battery charging and system power path management according to claim 1, characterized in that: Also includes: The battery voltage / current detection module (1008) is used to detect the battery voltage and battery current. When the battery is completely exhausted, the system adjusts the system voltage to above the minimum system voltage according to the minimum system voltage set in the register of the reference voltage module (1006).

4. The dual-phase buck switching charger with battery charging and system power path management according to claim 1, characterized in that: When the dual-phase buck circuit operates in a step-down charging mode, the switch control and current detection module (1009) detects the charging current in real time. When the charging current drops to zero but the input source is still overloaded, the system voltage starts to drop through the control switch control module and the interrupt control module (1002). When the system voltage is lower than the battery voltage, the switch control and current detection module (1009) controls the switch device (1010) to turn on, and the battery starts to discharge.

5. The dual-phase buck switching charger with battery charging and system power path management according to claim 4, characterized in that: When the system voltage is lower than the battery voltage and the battery discharge current is low, the switch control and current detection module (1009) controls the minimum drain-source voltage V DS Maintained at 30mv, as the discharge current increases, the switch device (1010) adopts a higher gate-source voltage V GS voltage to reduce the on-state resistance R DS (ON) until the switch device (1010) is fully turned on.

6. The dual-phase buck switching charger with battery charging and system power path management according to claim 5, characterized in that: The switch control and current detection module (1009) monitors the discharge current of the battery through the switch device (1010). When the discharge current of the battery is greater than the discharge overcurrent protection current threshold, the switch control and current detection module (1009) turns off the switch device (1010), transmits an abnormal signal to the protection module (1004), sets the corresponding control register bit of the digital logic and communication module (1003) to be disabled, and controls the interrupt and status output module (1005) to output an interrupt signal through the switch control module and the interrupt control module (1002), and notifies the host.

7. The dual-phase buck switching charger with battery charging and system power path management according to claim 6, characterized in that: The protection module (1004) reports various interrupt events to the host at the interrupt port through the interrupt and status output module (1005), including: identifying the type-c or adapter source; detecting a good input source; VBUS is higher than the battery voltage; VAC, VBUS are lower than the overvoltage threshold; VBUS is higher than the VBUS minimum operating voltage and the load capacity is greater than 30mA; input source removed; charging completed; battery connected; battery removed.

8. The dual-phase buck switching charger with battery charging and system power path management according to claim 1, characterized in that: When the input power supply voltage VAC is higher than the start-up threshold and lower than the overvoltage threshold, the bus voltage VBUS is powered on, the LDO linear power supply module (1001) is enabled, and a bias power supply is provided for the internal bias circuit, and gate drive is provided for the first high-side switch (1014), the second high-side switch (1013), the first low-side switch (1011), and the second low-side switch (1012) through the control switch control module and the interrupt control module (1002).

9. The dual-phase buck switching charger with battery charging and system power path management according to claim 1, characterized in that: The input current limiting setting is changed by modifying the register by the host. After the input current limiting setting is set, the corresponding control register of the digital logic and communication module (1003) is set to control the switch control module and the interrupt control module (1002) to enable the operation mode switching of the two-phase buck circuit, switching between the step-down charging mode and the step-up discharging mode.

10. The dual-phase buck switching charger with battery charging and system power path management according to claim 1, characterized in that: When the dual-phase buck circuit is controlled by the switch control module and the interrupt control module (1002) to enable battery charging, a charging cycle is automatically completed, and the charging cycle includes constant current mode trickle charging, constant current mode pre-charging, constant current high current charging, and constant voltage charging. When the battery voltage is higher than the charging threshold and the battery current is lower than the termination current, the switch control module and the interrupt control module (1002) control the termination of the charging cycle and close the switch device (1010).

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