Multi-port charging system

Abstract

The utility model relates to the technical field of charging circuits, and provides a multi-port charging system, which is characterized in that a first charging controller obtains a voltage value required by a first charging port, and generates a first adjusting signal according to the voltage value required by the first charging port; the second charging controller obtains a voltage value required by the second charging port and generates a second adjusting signal according to the voltage value required by the second charging port; when the voltage value required by the first charging port is greater than the voltage value required by the second charging port, a first adjusting signal is sent to the pre-stage switching converter to adjust the pre-stage output voltage signal to be equal to the voltage value required by the first charging port; the first adjusting signal is sent to the first post-stage switching converter to control a main power switch in the first post-stage switching converter to be kept in a normally-on state, and since the main power switch in the first post-stage switching converter is kept in the normally-on state and switching is not carried out any more, switching loss does not exist, only conduction loss is reduced, conversion loss is reduced, and the service life of the converter is prolonged. The conversion efficiency is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of charging circuits, and in particular, to a multi-port charging system. Background Art

[0002] With the increasing use of USB interfaces, charging adapters are also evolving from single-port outputs to dual or even multi-port outputs. Multi-port chargers often use a single fixed voltage output from a front-end AC-DC converter, which is then stepped down by multiple DC-DC converters to output the voltage to the respective ports. This means the adapter consists of a two-stage power supply, AC-DC and DC-DC, with efficiency losses incurred at each stage.

[0003] Generally, the conversion efficiency of DC-DC in large voltage difference buck mode is not ideal. In order to improve efficiency, it is often necessary to consider reducing the switching loss of the switch tube, the inductor core loss, the conduction loss of the switch tube, and the inductor conduction loss in the DC-DC. In related technologies, the switching loss of the switch tube and the inductor core loss are often reduced by reducing the switching frequency. However, too low a switching frequency leads to a greater inductance of the inductor, which will cause noise and loop stability problems. If the conduction loss is reduced to improve efficiency by reducing the on-resistance of the switch tube, it will not only be costly but also make the chip area larger. And if the conduction loss is reduced to improve efficiency by reducing the on-resistance of the inductor, the inductor wire diameter will be thicker and the size will be larger, affecting the space and cost of the whole machine. Utility Model Content

[0004] The purpose of the present disclosure is to provide a multi-port charging system to solve the problems in the related art.

[0005] In order to achieve the above-mentioned objectives, the present disclosure provides a multi-port charging system, which includes: a front-stage switching converter for receiving an input voltage signal and converting the input voltage signal into a front-stage output voltage signal; a first rear-stage switching converter for receiving the front-stage output voltage signal and converting the front-stage output voltage signal into a first bus voltage signal; a second rear-stage switching converter for receiving the front-stage output voltage signal and converting the front-stage output voltage signal into a second bus voltage signal; a first charging port for coupling to the output end of the first rear-stage switching converter to receive the first bus voltage signal; a second charging port for coupling to the output end of the second rear-stage switching converter to receive the second bus voltage signal; a first charging controller for coupling to the first charging port and obtaining the first bus voltage signal; The first charging controller is configured to couple to the second charging port and obtain the voltage value required by the second charging port, and generate a first adjustment signal based on the voltage value required by the second charging port; the second charging controller is configured to couple to the second charging port and obtain the voltage value required by the second charging port, and generate a second adjustment signal based on the voltage value required by the second charging port; when the voltage value required by the first charging port is greater than the voltage value required by the second charging port, the first charging controller is configured to send the first adjustment signal to the preceding switching converter to adjust the preceding output voltage signal to be equal to the voltage value required by the first charging port, and is further configured to send the first adjustment signal to the first succeeding switching converter to control the main power switch in the first succeeding switching converter to remain in a normally-on state, wherein the second adjustment signal is configured to adjust the value of the second bus voltage signal to be equal to the voltage value required by the second charging port.

[0006] With the above technical solution, a first charging controller obtains the voltage value required by the first charging port and generates a first adjustment signal based on the voltage value required by the first charging port. A second charging controller obtains the voltage value required by the second charging port and generates a second adjustment signal based on the voltage value required by the second charging port. When the voltage value required by the first charging port is greater than the voltage value required by the second charging port, the first charging controller transmits the first adjustment signal to the preceding switching converter to adjust the preceding output voltage signal to equal the voltage value required by the first charging port. The first adjustment signal is also transmitted to the first succeeding switching converter to control the main power switch in the first succeeding switching converter to remain in a normally-on state. Because the first adjustment signal controls the main power switch in the first succeeding switching converter to remain in a normally-on state and no longer switch, there is no switching loss, only conduction loss, which reduces conversion loss and improves conversion efficiency. This achieves maximum conversion efficiency at a low cost, with minimal loss and low heat generation.

[0007] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0009] Figure 1 is a schematic diagram showing a multi-port charging system according to an exemplary embodiment.

[0010] Figure 2 is a schematic diagram showing another multi-port charging system according to an exemplary embodiment.

[0011] Figure 3 is a schematic diagram of a DC-DC feedback circuit according to an exemplary embodiment.

[0012] Figure 4 is a schematic diagram of another DC-DC feedback circuit according to an exemplary embodiment.

[0013] Figure 5 is a schematic diagram of an AC-DC feedback circuit according to an exemplary embodiment.

[0014] Figure 6 is a schematic diagram showing a DC-DC controller according to an exemplary embodiment.

[0015] Description of Reference Numerals

[0016] 10 - front-stage switching converter; VDC - front-stage output voltage signal; 11 - first rear-stage switching converter; VBUS1 - first bus voltage signal; 12 - second rear-stage switching converter; VBUS2 - second bus voltage signal; REG1 - first regulation signal; REG1-1 - bus voltage regulation signal; REG1-2 - front-stage output voltage regulation signal; REG2 - second regulation signal; SW1 - first switch; SW2 - second switch; SW3 - third switch; SW4 - fourth switch; HS - main power switch; LS - freewheeling power switch; CTL1 - first switch control signal; CTL2 - second switch control signal; R1 - first voltage-dividing resistor; R2 - second voltage-dividing resistor; R3 - third voltage-dividing resistor; R4 - fourth voltage-dividing resistor; R5 - fifth voltage-dividing resistor; R6 - sixth voltage-dividing resistor; R7 - seventh voltage-dividing resistor; R8 - eighth voltage-dividing resistor; R9 - ninth voltage-dividing resistor; R10 - tenth voltage-dividing resistor; VFB1 - post-stage feedback signal; VFB2 - post-stage feedback signal; VOL - three-terminal voltage regulator; OC - optocoupler isolator. DETAILED DESCRIPTION

[0017] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0018] In the following description, words such as “first” and “second” are only used for the purpose of distinguishing the description and should not be understood as indicating or implying relative importance or order.

[0019] With the increasing use of USB interfaces, charging adapters are also evolving from single-port outputs to dual-port or multi-port outputs. Multi-port chargers often use a single fixed voltage output from a front-end AC-DC converter, which is then stepped down by multiple DC-DC converters to output to the respective ports. This means the adapter consists of a two-stage power supply, AC-DC and DC-DC, with efficiency losses incurred at each stage.

[0020] In related technologies, the switching loss of the switching tube and the core loss of the inductor are often reduced by lowering the switching frequency. However, if the switching frequency is too low, the inductor's inductance will be greater, and it will cause noise and loop stability problems. If the conduction loss is reduced by reducing the on-resistance of the switching tube to improve efficiency, it will not only be costly but also increase the chip area. And reducing the on-resistance of the inductor will make the inductor wire diameter thicker and the size larger, affecting the space and cost of the entire machine.

[0021] Figure 1 FIG. 1 is a schematic diagram of a multi-port charging system according to an exemplary embodiment. In this embodiment, only a charging system with two ports is illustrated to avoid ambiguity. Figure 1 As shown, the multi-port charging system includes a front-stage switching converter 10, a first rear-stage DC-DC switching converter 11, a second rear-stage switching converter 12, a first charging port, a second charging port, a first charging controller, and a second charging controller. In one embodiment, the front-stage switching converter 10 is typically an AC-DC switching converter with a transformer for electrical isolation; the rear-stage switching converter is typically a DC-DC switching converter that performs a secondary step-down conversion on the output voltage of the AC-DC switching converter.

[0022] The front-stage switching converter 10 is configured to receive an input voltage signal VIN and convert the input voltage signal VIN into a front-stage output voltage signal VDC.

[0023] The first subsequent-stage switching converter 11 is configured to receive the previous-stage output voltage signal VDC and convert the previous-stage output voltage signal VDC into a first bus voltage signal VBUS1 .

[0024] The second subsequent-stage switching converter 12 is configured to receive the previous-stage output voltage signal VDC and convert it into a second bus voltage signal VBUS2. In one embodiment, the first subsequent-stage switching converter 11 and the second subsequent-stage switching converter 12 have identical circuit structures. In one embodiment, the first subsequent-stage switching converter 11 and the second subsequent-stage switching converter 12 can be implemented as integrated circuits. In one embodiment, the values ​​of the first bus voltage signal VBUS1 and the second bus voltage signal VBUS2 can be the same or different.

[0025] The first charging port is configured to be coupled to the output terminal of the first subsequent-stage switching converter 11 to receive the first bus voltage signal VBUS1 .

[0026] The second charging port is configured to couple to the output of the second subsequent switching converter 12 to receive the second bus voltage signal VBUS2. In one embodiment, the first and second charging ports are connected to external charging loads, such as mobile phones, tablet computers, power banks, and other charging devices, to provide the corresponding first and second bus voltage signals VBUS1 and VBUS2 to the corresponding charging devices. In one embodiment, the first and second charging ports include Type-C ports.

[0027] The first charging controller is configured to couple to the first charging port, obtain a voltage value required by the first charging port, and generate a first regulation signal REG1 based on the voltage value required by the first charging port. In one embodiment, the voltage value required by the first charging port is determined by an external charging device. The first charging port transmits the voltage value required by the external charging device to the first charging controller via a corresponding pin according to a communication transmission protocol. The specific communication transmission protocol can be selected based on hardware requirements. For example, in one embodiment, communication between the first charging port and the first charging controller is performed in accordance with the Power Delivery (PD) protocol standard developed by the USB-IF organization.

[0028] The second charging controller is configured to couple to the second charging port, obtain a voltage value required by the second charging port, and generate a second regulation signal REG2 based on the voltage value required by the second charging port. Similarly, in one embodiment, the voltage value required by the second charging port is determined by an external charging device. The second charging port transmits the voltage value required by the external charging device to the second charging controller via a corresponding pin according to a communication transmission protocol (e.g., the PD protocol).

[0029] In one embodiment, when it is detected that the voltage value required by one of the charging ports is the maximum, the charging controller connected to the corresponding charging port sends the generated adjustment signal to the front-stage switching converter to adjust the front-stage output voltage signal VDC to be equal to the voltage value required by the charging port. At the same time, the charging controller is also used to send the generated adjustment signal to the corresponding rear-stage switching converter to control the main power switch in the rear-stage switching converter to remain in a normally on state.

[0030] For example, when the voltage required by the first charging port is greater than the voltage required by the second charging port, the first charging controller is configured to send a first regulation signal REG1 to the preceding switching converter 10 to adjust the preceding output voltage signal VDC to the voltage required by the first charging port. The first charging controller is also configured to send the first regulation signal REG1 to the first subsequent switching converter 11 to control the main power switch HS in the first subsequent switching converter 11 to remain in a normally-on state. In this case, the first regulation signal REG1 sent to the first subsequent switching converter 11 is first used to adjust the first bus voltage signal VBUS1 to the voltage required by the first charging port. At this point, both the preceding output voltage signal VDC and the first bus voltage signal VBUS1 are equal to the voltage required by the first charging port, i.e., the input voltage of the first subsequent switching converter 11 is equal to the output voltage. Subsequently, upon detecting that its input voltage is equal to its output voltage, the first subsequent switching converter 11 controls its main power switch HS to remain in a normally-on state and no longer switch. At the same time, the second charging controller is used to send the second regulation signal REG2 to the second subsequent switching converter 12 to control the value of the second bus voltage signal VBUS2 output by the second subsequent switching converter 12 to be equal to the voltage value required by the second charging port.

[0031] Because the first regulation signal REG1 controls the main power switch HS in the first subsequent-stage switching converter 11 to remain in a normally-on state and no longer switch, there is no switching loss, only conduction loss. This reduces conversion losses and improves conversion efficiency. This achieves maximum conversion efficiency at a lower cost, with minimal losses and lower heat generation.

[0032] In other embodiments, if the voltage required by the first charging port is lower than the voltage required by the second charging port, the second charging controller generates a second regulation signal REG2. This second regulation signal REG2 is sent to the preceding switching converter 10 to adjust the preceding output voltage signal VDC to the voltage required by the second charging port. This second regulation signal REG2 is also sent to the second subsequent switching converter 12 to control the main power switch HS in the second subsequent switching converter 12 to remain in a normally-on state. In this case, both the preceding output voltage signal VDC and the second bus voltage signal VBUS2 are equal to the voltage required by the second charging port, meaning that the input voltage of the second subsequent switching converter 12 is equal to the output voltage. Therefore, the second subsequent switching converter 12 controls its main power switch HS to remain in a normally-on state and no longer switches. Simultaneously, the first charging controller sends the first regulation signal REG1 to the first subsequent switching converter 11 to control the output of the first bus voltage signal VBUS1 equal to the voltage required by the first charging port.

[0033] As mentioned earlier, Figure 1 The illustrated embodiment only illustrates a two-port charging system. The front-stage switching converter 10, the first rear-stage switching converter 11, the first charging port, and the first charging controller can be considered a first charging channel; the front-stage switching converter 10, the second rear-stage switching converter 12, the second charging port, and the second charging controller can be considered a second charging channel. Both the first and second charging channels share the same front-stage switching converter 10.

[0034] Based on this, the multi-port charging system can be expanded to include any number of charging channels. That is, in addition to the first and second charging channels, there can also be a third, ..., and Nth charging channel, where N is an integer greater than or equal to 2. The charging port with the highest required voltage is determined. The charging controller of the charging channel containing the charging port with the highest required voltage generates a regulation signal that is transmitted to the preceding switching converter 10 to adjust the value of the preceding output voltage signal VDC to that of the charging port with the highest required voltage. Furthermore, this regulation signal is also transmitted to the subsequent switching converter of that charging channel to control the main power switch HS in that subsequent switching converter to remain in a normally-on state. The charging controllers of the charging channels containing charging ports other than the charging port with the highest required voltage generate regulation signals that are transmitted to the corresponding subsequent switching converters to adjust the bus voltage signals they output to the required voltage of the corresponding charging port.

[0035] In one embodiment, a first charging controller and a second charging controller are electrically connected and communicate with each other to compare the voltage required by the first charging port with the voltage required by the second charging port. In one embodiment, the first charging controller also obtains the current required by the first charging port; the second charging controller also obtains the current required by the second charging port. The first charging controller calculates the power required by the first port based on the voltage and current values ​​obtained at the first port and transmits this information to the second charging controller via a communication line. The second charging controller calculates the power required by the second port based on the voltage and current values ​​obtained at the second port and transmits this information to the first charging controller via a communication line. The two charging controllers communicate with each other to achieve appropriate power allocation. In this embodiment, the first and second charging controllers include internal processing units, such as application-specific integrated circuits (ASICs), to implement the calculation and comparison functions. The first charging controller can be configured to compare the voltage value required by the first charging port with the voltage value required by the second charging port and communicate the comparison result to the second charging controller; the second charging controller can also be configured to compare the voltage value required by the first charging port with the voltage value required by the second charging port and communicate the comparison result to the first charging controller; the first charging controller and the second charging controller can also be configured to only communicate with each other about the voltage values ​​required by their respective charging ports, and to generate respective adjustment signals after independently comparing the voltage value required by the first charging port with the voltage value required by the second charging port.

[0036] In another embodiment, see Figure 2 The multi-port charging system may further include a processor. The processor is electrically connected to and in communication with the first charging controller and the second charging controller. The processor is configured to compare the voltage required by the first charging port with the voltage required by the second charging port, and control the first charging controller to generate a first adjustment signal and the second charging controller to generate a second adjustment signal.

[0037] The processor may be, but is not limited to, a microprocessor (Micro Controller Unit, MCU), a digital signal processor (Digital Signal Processor, DSP), a digital signal processing device (Digital Signal Processing Device, DSPD), a programmable logic device (Programmable Logic Device, PLD), a field programmable gate array (Field Programmable Gate Array, FPGA), etc.

[0038] Continue to see Figure 1 In one possible implementation, the multi-port charging system may further include a first switch SW1 and a second switch SW2 .

[0039] The first switch SW1 has a first terminal, a second terminal, and a control terminal. The first terminal of the first switch SW1 is coupled to the first subsequent switching converter 11 to receive the first bus voltage signal VBUS1. The second terminal of the first switch SW1 is coupled to the first charging port. The control terminal of the first switch SW1 is coupled to the first charging controller. The first charging controller is configured to control the first switch SW1 to conduct when the multi-port charging system and the charging device at the first charging port reach a handshake agreement. In one embodiment, the handshake agreement includes ensuring that the voltage value of the first bus voltage signal VBUS1 is equal to the voltage value required by the first charging port.

[0040] The second switch SW2 has a first terminal, a second terminal, and a control terminal. The first terminal of the second switch SW2 is coupled to the second subsequent-stage switching converter 12 to receive the second bus voltage signal VBUS2. The second terminal of the second switch SW2 is coupled to the second charging port. The control terminal of the second switch SW2 is coupled to the second charging controller. The second charging controller is configured to control the second switch SW2 to conduct when the multi-port charging system and the charging device at the second charging port reach a handshake agreement. In one embodiment, the handshake agreement includes ensuring that the voltage value of the second bus voltage signal VBUS2 is equal to the voltage value required by the second charging port.

[0041] In addition, the first charging controller can also be used to detect the value of the first bus voltage signal VBUS1 and the current flowing through the first switch SW1, and control the first switch SW1 to open when an abnormal voltage and / or current is detected, thereby protecting the first charging port and its external charging load. Similarly, the second charging controller can also be used to detect the value of the second bus voltage signal VBUS2 and the current flowing through the second switch SW2, and control the second switch SW2 to open when an abnormal voltage and / or current is detected, thereby protecting the second charging port and its external charging load. Therefore, the introduction of the first switch SW1 and the second switch SW2 can further improve the reliability and safety of the charging system.

[0042] Continue to see Figure 1 In one possible implementation, the first regulation signal REG1 includes a bus voltage regulation signal REG1-1 and a front-stage output voltage regulation signal REG1-2. The bus voltage regulation signal REG1-1 is sent to the first rear-stage switching converter 11 to control the main power switch HS in the first rear-stage switching converter 11 to remain in a normally-on state. The front-stage output voltage regulation signal REG1-2 is sent to the front-stage switching converter 10 to adjust the front-stage output voltage signal VDC to the voltage required by the first charging port.

[0043] First, the bus voltage regulation signal REG1-1 regulates the first bus voltage signal VBUS1 to be equal to the voltage value required by the first charging port. Figure 1 In the illustrated embodiment, the first subsequent-stage switching converter 11 is illustrated as a buck (BUCK) topology switching converter, including a buck power stage circuit, a DC-DC feedback circuit, and a DC-DC controller. The input of the first subsequent-stage switching converter 11 receives the output voltage signal VDC of the previous stage, and the output of the first subsequent-stage switching converter 11 provides a first bus voltage signal VBUS1.

[0044] The buck power stage circuit includes a main power switch HS and a freewheeling power switch LS. A first terminal of the main power switch HS is coupled to the input terminal of the first subsequent-stage switching converter 11, a second terminal of the main power switch HS is coupled to the output terminal of the first subsequent-stage switching converter 11 via an inductor, and the freewheeling power switch LS is coupled between the second terminal of the main power switch HS and a reference ground.

[0045] The DC-DC feedback circuit is configured to receive the first bus voltage signal VBUS1 and the bus voltage regulation signal REG1 - 1 , and generate a post-stage feedback signal VFB1 according to the first bus voltage signal VBUS1 and the bus voltage regulation signal REG1 - 1 .

[0046] The DC-DC controller is used to receive the post-stage feedback signal VFB1 and the voltage sampling signal representing the front-stage output voltage signal VDC, and generate a first switch control signal CTL1 based on the post-stage feedback signal VFB1 and the voltage sampling signal. The first switch control signal CTL1 is used to control the on-time and off-time of the main power switch HS and the freewheeling power switch LS, thereby converting the front-stage output voltage signal VDC into a first bus voltage signal VBUS1.

[0047] In one embodiment, the first switch control signal CTL1 includes a first control signal and an inverted version of the first control signal. The first control signal is used to control the on / off switching of the main power switch HS, and the inverted version of the first control signal is used to control the on / off switching of the freewheeling power switch LS. Those skilled in the art will appreciate that the inverted version of the first control signal is a signal that is logically complementary to the first control signal. In one embodiment, the freewheeling power switch LS can also be replaced with an uncontrollable diode.

[0048] exist Figure 1In the illustrated embodiment, the main power switch HS and the freewheeling power switch LS are illustrated as N-type metal oxide semiconductor field effect transistors (MOSFETs). Those skilled in the art will appreciate that, in other embodiments, the main power switch HS and the freewheeling power switch LS may also include other suitable semiconductor switching device types, such as junction field-effect transistors (JFETs), insulated gate bipolar transistors (IGBTs), and double-diffusion metal oxide semiconductors (DMOSs).

[0049] In one possible implementation, the bus voltage regulation signal REG1-1 includes a current signal, which can be a source current or a sink current. Source current is a current signal flowing out of the first charge controller, while sink current is a current signal flowing into the first charge controller. In one embodiment, the first charge controller includes an IDAC pin that provides the voltage regulation signal REG1-1. Through the IDAC pin, the first charge controller can provide the source current signal or the sink current signal to the DC-DC feedback circuit in the first subsequent switching converter 11.

[0050] Figure 3 A schematic diagram of a DC-DC feedback circuit according to an exemplary embodiment is shown as follows: Figure 3 As shown, the DC-DC feedback circuit may include a first voltage-dividing resistor R1 and a second voltage-dividing resistor R2. The first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 are coupled in series between the first bus voltage signal VBUS1 and the first reference ground GND1. The IDAC pin of the first charge controller is coupled to the common node of the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 to provide the bus voltage regulation signal REG1-1. The voltage at the common node of the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 is the post-stage feedback signal VFB1.

[0051] Combine Figure 1 and Figure 3 In the schematic diagram of the embodiment shown, the principle of the first charging controller controlling the first subsequent switching converter 11 to output the first bus voltage signal VBUS1 is as follows:

[0052] When the bus voltage regulation signal REG1-1, acting as a current signal, is zero, appropriate first and second voltage-dividing resistors R1 and R2 are selected to generate a downstream feedback signal VFB1. This downstream feedback signal VFB1 is then sent to a DC-DC controller and compared with a preset reference voltage signal to generate a first switch control signal CTL1. This first switch control signal CTL1 controls the on and off times of the main power switch HS and the freewheeling power switch LS, thereby controlling a default output voltage of the first bus voltage signal VBUS1 output by the first downstream switching converter 11. When the voltage regulation signal REG1-1 generated by the first charging controller is a current sink signal flowing to the IDAC pin, the current flowing through the first voltage-dividing resistor R1 increases. Assuming the voltage of the first bus voltage signal VBUS1 output by the first downstream switching converter 11 remains constant, the voltage drop across the first voltage-dividing resistor R1 increases, causing the voltage of the downstream feedback signal VFB1 to fall below the reference value. This causes the first switch control signal CTL1 to extend the on-time of the main power switch HS, and the first bus voltage signal VBUS1 begins to increase. After a plurality of switching cycles, when the first bus voltage signal VBUS1 increases to a desired value so that the voltage of the subsequent feedback signal VFB1 is equal to the reference voltage, the first subsequent switching converter 11 enters a steady state.

[0053] Similarly, when the voltage regulation signal REG1-1 generated by the first charge controller is a current-sourcing signal flowing out of the IDAC pin, the current flowing through the second voltage-dividing resistor R2 increases, the voltage of the downstream feedback signal VFB1 rises above the reference value, the first switch control signal CTL1 controls the on-time of the main power switch HS to decrease, and the first bus voltage signal VBUS1 begins to decrease. After multiple switching cycles, when the first bus voltage signal VBUS1 decreases to the desired value, such that the voltage of the downstream feedback signal VFB1 equals the reference voltage, the first downstream switching converter 11 enters a steady state. In other words, the desired value of the first bus voltage signal VBUS1 can be adjusted by setting different first and second voltage-dividing resistors R1 and R2 and / or adjusting the value of the voltage regulation signal REG1-1.

[0054] In another possible embodiment, the bus voltage regulation signal REG1-1 includes a logic high or low level signal. In one embodiment, the first charge controller has a GPIO pin that provides the voltage regulation signal REG1-1. Through the GPIO pin, the first charge controller can provide a logic high or low level signal to the DC-DC feedback circuit in the first subsequent switching converter 11. Figure 4 is a schematic diagram of another DC-DC feedback circuit according to an exemplary embodiment. Figure 4 As shown, the DC-DC feedback circuit may include a third voltage-dividing resistor R3, a fourth voltage-dividing resistor R4, a fifth voltage-dividing resistor R5 and a third switch SW3.

[0055] The third voltage-dividing resistor R3 and the fourth voltage-dividing resistor R4 are coupled in series between the first bus voltage signal VBUS1 and the first reference ground GND1; the first end of the fifth voltage-dividing resistor R5 is connected to the common node of the third voltage-dividing resistor R3 and the fourth voltage-dividing resistor R4; the third switch SW3 has a first end, a second end and a control end, the first end of the third switch SW3 is connected to the second end of the fifth voltage-dividing resistor R5, the second end of the third switch SW3 is connected to the first reference ground GND1, and the control end of the third switch SW3 receives the bus voltage adjustment signal REG1-1; the voltage at the common node of the third voltage-dividing resistor R3, the fourth voltage-dividing resistor R4 and the fifth voltage-dividing resistor R5 is the post-stage feedback signal VFB1.

[0056] When the bus voltage regulation signal REG1-1 is at a logic high level, the third switch SW3 turns on, connecting the fifth and fourth voltage-dividing resistors R5 and R4 in parallel. This reduces the voltage at the common node, thereby decreasing the downstream feedback signal VFB1. This causes the voltage of the downstream feedback signal VFB1 to fall below a reference value. The first switch control signal CTL1 controls the on-time of the main power switch HS to increase, causing the first bus voltage signal VBUS1 to begin to increase. After multiple switching cycles, when the first bus voltage signal VBUS1 reaches a desired value, making the voltage of the downstream feedback signal VFB1 equal to the reference voltage, the first downstream switching converter 11 enters a steady state. Therefore, by setting different values ​​for the first and second voltage-dividing resistors R1 and R2 and controlling the logic state of the bus voltage regulation signal REG1-1, the desired value of the first bus voltage signal VBUS1 can be adjusted.

[0057] In other embodiments, multiple sets of series-connected voltage-divider resistors and switches coupled between the common node of the third and fourth voltage-divider resistors R3 and R4 and the first reference ground GND1 may be provided. By controlling the switches, the voltage-divider resistors are controlled to be connected in parallel to the fourth voltage-divider resistor R4, thereby varying the value of the downstream feedback signal VFB1 and thereby adjusting the desired value of the first bus voltage signal VBUS1. The multiple sets of series-connected voltage-divider resistors and switches may be selectively connected in parallel across the fourth voltage-divider resistor R4, or multiple sets may be incorporated across the fourth voltage-divider resistor R4 to stabilize the first bus voltage signal VBUS1 output by the first downstream switching converter 11 at the desired value. Each switch in each set of voltage-divider resistors and switches is controlled by a bus voltage regulation signal REG1-1. That is, in this embodiment, the first charge controller may have multiple GPIO pins, each providing an independent bus voltage regulation signal to control a corresponding switch.

[0058] It should be understood that the structure and working principle of the second post-stage switching converter 12 are identical to those of the first post-stage switching converter 11, and the second adjustment signal REG2 can adjust the second bus voltage signal VBUS2 to be equal to the voltage value required by the second charging port by the same control method as the bus voltage adjustment signal REG1-1. In order not to obscure the key points, this embodiment will not be described in detail here.

[0059] At the same time, the front-stage output voltage adjustment signal REG1-2 is sent to the front-stage switching converter 10 to adjust the front-stage output voltage signal VDC to be equal to the voltage value required by the first charging port. Figure 1 In the illustrated embodiment, the front-stage switching converter 10 may include a power stage circuit, an AC-DC feedback circuit, and an AC-DC controller.

[0060] The power stage circuit includes at least one power switch. In the front-stage switching converter, the power stage circuit can be, but is not limited to, a topology with a transformer isolation structure, such as a flyback circuit topology, a forward circuit topology, or an LLC circuit topology.

[0061] The AC-DC feedback circuit is configured to receive the front-stage output voltage signal VDC and the front-stage output voltage regulation signals REG1-2, and generate a front-stage feedback signal VFB2 based on the front-stage output voltage signal VDC and the front-stage output voltage regulation signals REG1-2. In one embodiment, multiple front-stage output voltage regulation signals REG1-2 may be generated by the first charge controller to implement multiple gear shifting of the AC-DC output front-stage output voltage signal VDC.

[0062] I understand. Figure 1 The illustrated embodiment assumes that the voltage required by the first charging port is greater than the voltage required by the second charging port, and therefore the pre-stage output voltage regulation signal REG1-2 is provided by the first charging controller. In other applications, if the voltage required by the first charging port is less than the voltage required by the second charging port, the AC-DC feedback circuit will receive the pre-stage output voltage regulation signal provided by the second charging controller.

[0063] The AC-DC controller is configured to receive a front-stage feedback signal VFB2 and generate a second switch control signal CTL2 based on the front-stage feedback signal VFB2. The second switch control signal CTL2 is configured to control the on-time and off-time of at least one power switch in the power stage circuit, thereby adjusting the front-stage output voltage signal VDC to the voltage value required by the first charging port.

[0064] Similar to how the bus voltage regulation signal REG1-1 regulates the first bus voltage signal VBUS1, the pre-stage output voltage regulation signal REG1-2 can also use the same signal format as the bus voltage regulation signal REG1-1 to regulate the value of the pre-stage output voltage signal VDC. That is, the pre-stage output voltage regulation signal REG1-2 can be in the form of current sinking or current sourcing, or in the form of a logic high or low level signal. Figure 5 Taking the previous stage output voltage regulation signal REG1-2 as a logic high or low level signal as an example, Figure 5 is a schematic diagram of an AC-DC feedback circuit according to an exemplary embodiment, and according to Figure 5 The schematic circuit diagram describes the principle of regulating the front-stage output voltage signal VDC using the front-stage output voltage regulating signal REG1-2.

[0065] See also Figure 5 The AC-DC feedback circuit includes a sixth voltage-dividing resistor R6, a seventh voltage-dividing resistor R7, an eighth voltage-dividing resistor R8, a ninth voltage-dividing resistor R9, a tenth voltage-dividing resistor R10, a fourth switch SW4, a three-terminal voltage regulator VOL, and an optocoupler isolator OC.

[0066] The sixth and seventh voltage-dividing resistors R6 and R7 are coupled in series between the output terminal of the preceding switching converter 10 and the first reference ground GND1. The first end of the eighth voltage-dividing resistor R8 is connected to the common node of the sixth and seventh voltage-dividing resistors R6 and R7. The fourth switch SW4 has a first end, a second end, and a control end. The first end of the fourth switch SW4 is connected to the second end of the eighth voltage-dividing resistor R8, the second end of the fourth switch SW4 is connected to the first reference ground GND1, and the control end of the fourth switch SW4 receives the preceding output voltage adjustment signal REG1-2. The first end of the ninth voltage-dividing resistor R9 is connected to the output terminal of the preceding switching converter 10. The three-terminal voltage regulator VOL has a first end, a second end, and a third end. The second end of the three-terminal voltage regulator VOL is connected to the common node of the sixth and seventh voltage-dividing resistors R6 and R7, and the third end of the three-terminal voltage regulator VOL is connected to the first reference ground GND1. The optocoupler isolator OC has a first terminal, a second terminal, a third terminal and a fourth terminal. The first terminal of the optocoupler isolator OC is connected to the second terminal of the ninth voltage divider resistor R9, the second terminal of the optocoupler isolator OC is connected to the first terminal of the three-terminal voltage regulator VOL, and the third terminal of the optocoupler isolator OC is coupled to the power supply voltage source V through the tenth voltage divider resistor R10. DD , and the third end of the optocoupler isolator OC is connected to the input end of the AC-DC controller for providing a front-stage feedback signal VFB2, and the fourth end of the optocoupler isolator OC is connected to the second reference ground GND2.

[0067] It should be understood that the second reference ground GND2 connected to the fourth terminal of the optocoupler isolator OC is the primary reference ground of the transformer in the previous switching converter, and the first reference ground GND1 connected to the third terminal of the three-terminal voltage regulator VOL is the secondary reference ground of the transformer. The primary and secondary side signals of the transformer are electrically isolated by the optocoupler isolator OC.

[0068] By outputting different logic states of the pre-stage output voltage adjustment signals REG1-2, the fourth switch SW4 can be turned on or off, thereby changing the resistance between the common node NODE and the first reference ground GND1, and thus the voltage at the common node NODE. The common node NODE is the second terminal of the three-terminal voltage regulator VOL. Changing the voltage at the second terminal of the three-terminal voltage regulator VOL changes the current flowing between the first and third terminals of the three-terminal voltage regulator VOL, thereby adjusting the current between the first and second terminals of the optocoupler isolator OC, and ultimately adjusting the value of the pre-stage feedback signal VFB2. If the voltage of the pre-stage feedback signal VFB2 is not equal to its reference value, the second switch control signal CTL2 will control the on-time of the power switch in the power stage circuit, thereby adjusting the value of the pre-stage output voltage signal VDC, ultimately making the value of the pre-stage output voltage signal VDC equal to the voltage required by the first charging port.

[0069] Furthermore, when the values ​​of the front-stage output voltage signal VDC and the first bus voltage signal VBUS1 are both adjusted to the voltage required by the first charging port, the DC-DC controller in the first subsequent-stage switching converter 11 detects that its input and output voltages are equal. Therefore, it generates a first control signal CTL1 to control the main power switch HS to remain in a normally-on state and the freewheeling power switch LS to remain in a normally-off state. Consequently, no switching is performed in the first subsequent-stage switching converter 11, resulting in no switching losses or core losses, and high efficiency.

[0070] The DC-DC controller inside the first subsequent-stage switching converter 11 may include various circuit structures according to different control methods. Figure 6 is a schematic diagram of a DC-DC controller according to an exemplary embodiment. Figure 6 , the DC-DC controller includes a hysteresis comparator circuit, a voltage control loop and a logic circuit.

[0071] The hysteresis comparator circuit has a first input, a second input, and an output. The first input of the hysteresis comparator circuit is connected to the output of the preceding switching converter to receive a voltage sampling signal VDC-sen representing the preceding output voltage signal VDC. The second input of the hysteresis comparator circuit is connected to the output of the DC-DC feedback circuit to receive the subsequent feedback signal VFB1. The hysteresis comparator circuit is configured to compare the voltage sampling signal VDC-sen with the subsequent feedback signal VFB1 and generate a comparison signal CA. In one embodiment, the comparison signal CA comprises logic high and low level signals. When the subsequent feedback signal VFB1 and the voltage sampling signal VDC-sen represent that the first bus voltage signal VBUS1 and the preceding output voltage signal VDC are equal or close to each other, the comparison signal CA is at a logic high level; otherwise, it is at a logic low level. "Close" here means that the difference between the first bus voltage signal VBUS1 and the preceding output voltage signal VDC is within a reasonably predetermined range.

[0072] The voltage control loop is configured to receive the post-stage feedback signal VFB1 and generate a pulse-width modulation signal PWM based on the post-stage feedback signal VFB1. In one embodiment, the pulse-width modulation signal PWM is a logic high or low level signal. Depending on the control method, the voltage control loop may include components such as an error amplifier, a voltage comparator, and a ramp signal generator. In other embodiments, a current sampling signal may also be incorporated into the voltage control loop.

[0073] The logic circuit is configured to receive a pulse-width modulation signal PWM and a comparison signal CA, and perform a logic operation on the pulse-width modulation signal PWM and the comparison signal CA to generate a first switch control signal CTL1. The first switch control signal CTL1 is also a logic high / low level signal. By varying the duty cycle of the first switch control signal CTL1, the on-time of the main power switch HS in the power stage circuit can be varied, thereby adjusting the value of the first bus voltage signal VBUS1. In one embodiment, when the comparison signal CA is at a logic low level, the first control signal CTL1 is the same as the pulse-width modulation signal PWM, and its on-duty cycle is determined by the post-stage feedback signal VFB1. When the comparison signal CA is at a logic low level, the first control signal CTL1 is the same as the comparison signal CA, and its on-duty cycle is 100%.

[0074] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0075] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0076] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A multi-port charging system, characterized in that: The multi-port charging system comprises: A front-stage switching converter, configured to receive an input voltage signal and convert the input voltage signal into a front-stage output voltage signal; A first rear-stage switching converter, configured to receive a front-stage output voltage signal and convert the front-stage output voltage signal into a first bus voltage signal; A second rear-stage switching converter, configured to receive a front-stage output voltage signal and convert the front-stage output voltage signal into a second bus voltage signal; A first charging port, configured to couple to an output terminal of a first subsequent switching converter to receive a first bus voltage signal; A second charging port, configured to be coupled to an output terminal of a second subsequent-stage switching converter to receive a second bus voltage signal; a first charging controller, configured to couple to the first charging port and obtain a voltage value required by the first charging port, and generate a first adjustment signal according to the voltage value required by the first charging port; a second charging controller, configured to couple to the second charging port and obtain a voltage value required by the second charging port, and generate a second adjustment signal according to the voltage value required by the second charging port; When the voltage value required by the first charging port is greater than the voltage value required by the second charging port, the first charging controller is configured to send a first adjustment signal to the preceding switching converter to adjust the preceding output voltage signal to be equal to the voltage value required by the first charging port, and further configured to send the first adjustment signal to the first succeeding switching converter to control the main power switch in the first succeeding switching converter to remain in a normally-on state, wherein the second adjustment signal is configured to adjust the value of the second bus voltage signal to be equal to the voltage value required by the second charging port.

2. The multi-port charging system according to claim 1, wherein: The first charging controller and the second charging controller are electrically connected and communicate with each other to compare the voltage value required by the first charging port and the voltage value required by the second charging port.

3. The multi-port charging system according to claim 1, wherein: The multi-port charging system further comprises: A processor is electrically connected to and communicates with the first charging controller and the second charging controller, respectively. The processor is used to compare the voltage value required by the first charging port and the voltage value required by the second charging port, and control the first charging controller to generate a first adjustment signal and control the second charging controller to generate a second adjustment signal.

4. The multi-port charging system according to claim 1, wherein: The multi-port charging system further comprises: a first switch having a first end, a second end, and a control end, wherein the first end of the first switch is coupled to the first subsequent-stage switching converter to receive a first bus voltage signal, the second end of the first switch is coupled to the first charging port, and the control end of the first switch is coupled to a first charging controller, the first charging controller being configured to control the first switch to be conductive after the charging system reaches a handshake agreement with a charging device externally connected to the first charging port; The second switch has a first end, a second end, and a control end. The first end of the second switch is coupled to the second post-stage switching converter to receive a second bus voltage signal. The second end of the second switch is coupled to the second charging port. The control end of the second switch is coupled to a second charging controller. The second charging controller is used to control the second switch to be turned on after the charging system reaches a handshake agreement with a charging device externally connected to the second charging port.

5. The multi-port charging system according to claim 1, wherein: The first regulating signal includes a bus voltage regulating signal and a front-stage output voltage regulating signal, and the first rear-stage switching converter includes: A BUCK power stage circuit includes a main power switch and a freewheeling power switch, wherein a first terminal of the main power switch is coupled to an input terminal of a first subsequent-stage switching converter, and a second terminal of the main power switch is coupled to an output terminal of the first subsequent-stage switching converter via an inductor; A DC-DC feedback circuit is configured to receive a first bus voltage signal and a bus voltage regulation signal, and generate a post-stage feedback signal according to the first bus voltage signal and the bus voltage regulation signal; A DC-DC controller is configured to receive a subsequent-stage feedback signal and a voltage sampling signal representing a preceding-stage output voltage signal, and generate a first switch control signal based on the subsequent-stage feedback signal and the voltage sampling signal, wherein the first switch control signal is configured to control the on and off times of the main power switch and the freewheeling power switch.

6. The multi-port charging system according to claim 5, characterized in that: The DC-DC controller includes: The hysteresis comparator circuit is used to receive the feedback signal of the subsequent stage and the voltage sampling signal representing the output voltage signal of the previous stage, and compare the feedback signal of the subsequent stage with the voltage sampling signal to generate a comparison signal; A voltage control loop, for receiving a subsequent stage feedback signal and generating a pulse width modulation signal according to the subsequent stage feedback signal; The logic circuit is used to receive the pulse width modulation signal and the comparison signal, and perform a logic operation on the pulse width modulation signal and the comparison signal to generate the first switch control signal.

7. The multi-port charging system according to claim 5, characterized in that: The bus voltage regulation signal includes a current signal, and the DC-DC feedback circuit includes: a first voltage-dividing resistor; a second voltage-dividing resistor, wherein the first voltage-dividing resistor and the second voltage-dividing resistor are coupled in series between the first bus voltage signal and the first reference ground; A common node between the first and second voltage-dividing resistors is coupled to a first charging controller to receive a bus voltage regulation signal, and a voltage at the common node between the first and second voltage-dividing resistors is the post-stage feedback signal.

8. The multi-port charging system according to claim 5, characterized in that: The bus voltage regulation signal includes a logic high or low level signal, and the DC-DC feedback circuit includes: The third voltage divider resistor; a fourth voltage-dividing resistor, wherein the third voltage-dividing resistor and the fourth voltage-dividing resistor are coupled in series between the first bus voltage signal and the first reference ground; a fifth voltage-dividing resistor, wherein a first end of the fifth voltage-dividing resistor is connected to a common node of the third voltage-dividing resistor and the fourth voltage-dividing resistor; The third switch has a first end, a second end and a control end, the first end of the third switch is connected to the second end of the fifth voltage-dividing resistor, the second end of the third switch is connected to the first reference ground, the control end of the third switch receives the bus voltage regulation signal, and the voltage at the common node of the third voltage-dividing resistor, the fourth voltage-dividing resistor and the fifth voltage-dividing resistor is the post-stage feedback signal.

9. The multi-port charging system according to claim 5, wherein: The front-stage switching converter comprises: A power stage circuit comprising at least one power switch; an AC-DC feedback circuit, configured to receive a front-stage output voltage signal and a front-stage output voltage adjustment signal, and generate a front-stage feedback signal according to the front-stage output voltage signal and the front-stage output voltage adjustment signal; The AC-DC controller is configured to receive a front-stage feedback signal and generate a second switch control signal according to the front-stage feedback signal, wherein the second switch control signal is configured to control the on and off time of the at least one power switch.

10. The multi-port charging system according to claim 9, wherein: The front-stage output voltage regulation signal includes a logic high and low level signal, and the AC-DC feedback circuit includes: a sixth voltage-dividing resistor; a seventh voltage-dividing resistor, wherein the sixth voltage-dividing resistor and the seventh voltage-dividing resistor are coupled in series between the output terminal of the preceding switching converter and the first reference ground; an eighth voltage-dividing resistor, wherein a first end of the eighth voltage-dividing resistor is connected to a common node of the sixth voltage-dividing resistor and the seventh voltage-dividing resistor; a fourth switch having a first end, a second end, and a control end, wherein the first end of the fourth switch is connected to the second end of the eighth voltage-dividing resistor, the second end of the fourth switch is connected to the first reference ground, and the control end of the fourth switch receives a previous-stage output voltage adjustment signal; a ninth voltage-dividing resistor, wherein a first end of the ninth voltage-dividing resistor is connected to an output end of the preceding switching converter; a three-terminal voltage regulator having a first terminal, a second terminal, and a third terminal, wherein the second terminal of the three-terminal voltage regulator is connected to a common node of the sixth voltage-dividing resistor and the seventh voltage-dividing resistor, and the third terminal of the three-terminal voltage regulator is connected to a first reference ground; Tenth voltage resistor; An optocoupler isolator has a first end, a second end, a third end and a fourth end, the first end of the optocoupler isolator is connected to the second end of the ninth voltage divider resistor, the second end of the optocoupler isolator is connected to the first end of the three-terminal voltage regulator, the third end of the optocoupler isolator is coupled to the power supply voltage source through the tenth voltage divider resistor, and the fourth end of the optocoupler isolator is connected to the second reference ground.

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