High-power in-vehicle USB hub with ground offset compensation

Abstract

A high-power in-vehicle USB hub with ground offset compensation includes a current input terminal, a current loop terminal, an input current detection circuit, a microcontroller, a ground level compensation Buck circuit, several charging output power supply circuits, and several Type-C interfaces, the same number as the charging output power supply circuits. This in-vehicle USB hub uses the input current detection circuit to collect the magnitude of the power supply current entering the hub. The microcontroller calculates the ground compensation voltage based on a preset ground impedance value and outputs a corresponding PWM signal to control the ground level compensation Buck circuit to output the corresponding compensation voltage to the ground, thereby solving the signal transmission distortion problem caused by ground offset due to large output current.

Description

Technical Field

[0001] This invention relates to USB hub technology. Background Technology

[0002] In a vehicle environment, a 150W high-power USB hub (PD HUB) can draw up to approximately 15A of input current. Due to the inherent resistance of the power supply cable, a voltage difference will exist between the GND of the PD HUB and the vehicle's head unit (HU). This phenomenon is called ground offset. When the voltage difference exceeds 125mV, it can cause distortion of the USB communication signals D+ and D-, thus affecting USB communication between the PD HUB and the host. Figure 1 A schematic diagram illustrating the ground offset that occurs in an existing USB hub is shown. Figure 1 As shown, the resistance of the ground wire between the vehicle host 200 and the USB hub 100a is R1. The signal transmitted on the data line will be offset relative to the signal ground SGND, thereby disrupting the normal communication of the USB hub 100a.

[0003] Currently, to address signal transmission distortion caused by ground offset, the main methods used are ground compensation chip VA6000 for ground compensation or isolation using a PHY chip, with input and output GND also isolated from each other. Designs using VA6000 for ground compensation or PHY chip isolation require dedicated chips and separate power supplies, resulting in high implementation costs. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a high-power vehicle USB hub that can solve the signal transmission distortion problem caused by ground offset due to high output current.

[0005] This invention discloses a high-power in-vehicle USB hub with ground offset compensation. The USB hub includes a current input terminal, a current loop terminal, an input current detection circuit, a microcontroller, a ground level compensation Buck circuit, several charging output power circuits, and several Type-C interfaces equal in number to the number of charging output power circuits. The current inflow terminal of the input current detection circuit is connected to the current input terminal, the current outflow terminal of the input current detection circuit is connected to the input terminals of the several charging output power circuits, and the output terminal of the input current detection circuit is connected to the first input terminal of the microcontroller. The input current detection circuit is used to detect the in-vehicle USB hub... The input current of the line device is measured, and a voltage signal proportional to the input current is output. The output of the microcontroller is connected to the input of the low-level compensation Buck circuit. The microcontroller calculates the ground compensation voltage based on the voltage signal output by the input current detection circuit and the preset ground impedance value, and generates a corresponding PWM signal based on the ground compensation voltage. The output of the ground level compensation Buck circuit is connected to the current loop terminal. The ground level compensation Buck circuit outputs the ground compensation voltage to the current loop terminal based on the PWM signal. The current loop terminal is used to connect to the power ground. The outputs of several charging output power supply circuits are connected to several Type-C interfaces respectively.

[0006] This invention has at least the following advantages and features:

[0007] 1. The vehicle-mounted USB hub of this invention utilizes an input current detection circuit to collect the power supply current of the input hub. A microcontroller calculates the ground compensation voltage based on a preset ground impedance value and outputs a corresponding PWM signal to control the ground level compensation Buck circuit to output the corresponding compensation voltage. The output ground compensation voltage is connected to the power ground, reducing the ground voltage of the internal logic level of the vehicle-mounted USB hub. In this way, while ensuring high power output, it solves the problems of communication data signal distortion and communication anomalies caused by ground offset.

[0008] 2. This embodiment does not require adding more power rails, nor does it significantly increase the power loss of the product, and the cost is also significantly reduced compared to other signal conversion solutions. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This diagram illustrates the principle of the location offset between a high-power in-vehicle USB hub and the in-vehicle host.

[0011] Figure 2 A schematic block diagram of a high-power in-vehicle USB hub according to an embodiment of the present invention is shown.

[0012] Figure 3 A circuit diagram of an input current detection circuit according to an embodiment of the present invention is shown.

[0013] Figure 4 A circuit schematic diagram of a microcontroller according to an embodiment of the present invention is shown.

[0014] Figure 5 A circuit diagram of a ground level compensation Buck circuit according to an embodiment of the present invention is shown.

[0015] Figure 6 A schematic diagram of a charging output power supply circuit according to an embodiment of the present invention is shown. Detailed Implementation

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 2 A schematic block diagram of a high-power in-vehicle USB hub according to an embodiment of the present invention is shown. Please refer to... Figure 2 According to an embodiment of the present invention, a high-power vehicle USB hub 100 includes a current input terminal S1, a current loop terminal S2, an input current detection circuit 3, a microcontroller 4, a ground level compensation Buck circuit 5, a hub controller 6, a plurality of charging output power circuits 7, a plurality of Type-C interfaces 8 in the same number as the plurality of charging output power circuits 7, and a power supply circuit 9.

[0018] The current inflow terminal of the input current detection circuit 3 is connected to the current input terminal S1, and the current outflow terminal of the input current detection circuit is connected to the input terminals of several charging output power supply circuits 7 respectively. The output terminal of the input current detection circuit 3 is connected to the first input terminal of the microcontroller 4. The input current detection circuit 3 is used to detect the input current of the vehicle USB hub and output a voltage signal proportional to the input current.

[0019] Please combine Figure 3 As shown. In this embodiment, the input current detection circuit includes a current detection resistor R803 and an amplifier circuit 32.

[0020] The first terminal of the current sensing resistor R803 is connected to the current input terminal S1, and the second terminal of the current sensing resistor R803 is connected to the input terminals of several charging output power supply circuits 7. The input terminals of the amplifier circuit 32 are connected to the first and second terminals of the current sensing resistor R803, and the output terminal of the amplifier circuit is connected to the input terminal of the microcontroller 4.

[0021] The amplifier circuit 32 includes an amplifier chip, model INA213, manufactured by Texas Instruments. The IN+ pin of the amplifier chip is connected to the first end of the current sensing resistor R803 through resistor R804, and the IN- pin of the amplifier chip is connected to the second end of the current sensing resistor R803 through resistor R802. The OUT pin of the amplifier chip is connected to the first input terminal of the microcontroller 4.

[0022] In this embodiment, the amplifier chip monitors the voltage across the sampling resistor R803, amplifies the voltage across the sampling resistor R803 by 50 times, and outputs it to the first input terminal of the microcontroller 4 (i.e., the AD pin of the DSP controller chip described below).

[0023] The output of the microcontroller 4 is connected to the input of the ground level compensation Buck circuit 5. The microcontroller 4 is used to calculate the ground compensation voltage based on the voltage signal output by the input current detection circuit 3 and the preset ground impedance value, and generate the corresponding PWM signal based on the ground compensation voltage.

[0024] Please see Figure 4 In this embodiment, the microcontroller 4 is a DSP controller, model TMS320F280022, manufactured by Texas Instruments. This DSP controller chip has 12-bit AD acquisition and 150ps PWM output.

[0025] Pin 15 of the DSP controller samples the voltage of amplifier circuit 32 and calculates the voltage across current sensing resistor R803 to convert it into the magnitude of the input current. Based on the actual power supply line length, wire diameter, and actual operating temperature provided by the vehicle manufacturer, the impedance R_cable of the ground wire 300 between the vehicle host 200 and USB hub 100 can be calculated and pre-stored in the DSP controller. This calculation formula is a known technique. Multiplying the sampled input current by the impedance on ground wire 300 yields the offset voltage (i.e., ground compensation voltage) on ground wire 300. The DSP controller outputs a PWM signal with the corresponding duty cycle from pins 51 and 52 to the ground level compensation Buck circuit 5 based on this ground compensation voltage. Furthermore, pin 24 of the DSP controller samples the voltage output from the ground level compensation Buck circuit (i.e., the second input terminal of microcontroller 4 is connected to the output terminal of the ground level compensation Buck circuit 5), and performs closed-loop control on the PWM signal output by the DSP controller based on the output voltage of the ground level compensation Buck circuit 5.

[0026] The output terminal of the ground level compensation Buck circuit 5 is connected to the current loop terminal S2. The ground level compensation Buck circuit 5 outputs a ground compensation voltage to the current loop terminal S2 according to the PWM signal. The current loop terminal S2 is connected to the power ground of the vehicle host 200 through the ground wire 300. The ground compensation voltage can make the voltage on the ground wire 300 0V, which is consistent with the voltage level of KL31_HU on the car.

[0027] Please refer to Figure 5 The ground level compensation Buck circuit 5 includes a half-bridge drive circuit 51, a half-bridge circuit 52, and a filter circuit 53.

[0028] The input terminal of the half-bridge drive circuit 51 is connected to the output terminal of the microcontroller 4, the output terminal of the half-bridge drive circuit 51 is connected to the input terminal of the half-bridge circuit 52, the output terminal of the half-bridge circuit 52 is connected to the input terminal of the filter circuit 53, and the output terminal of the filter circuit 53 is connected to the current loop terminal S2.

[0029] In this embodiment, the half-bridge drive circuit is composed of a UCC27282-Q1 half-bridge drive chip manufactured by Texas Instruments. The upper and lower half-bridge switch transistors of the half-bridge circuit 52 are both NMOS transistors. The filter circuit is an LC filter circuit, which includes a power inductor L801, capacitors C805, C806, C807, and an electrolytic capacitor CE802.

[0030] In this embodiment, the output of the DSP controller is connected to pins 5 and 6 of the half-bridge driver chip UCC27828-Q1. Based on the PWM signal from the DSP controller, the half-bridge driver chip outputs a high-drive-capability PWM signal through pins HO (pin 3) and LO (pin 8), periodically turning NMOS transistors Q802A and Q802B on and off. This outputs a periodic square wave. The LC filter circuit filters the square wave into a stable DC voltage, which is a ground level compensation voltage equal to the voltage difference flowing across the two ends of ground line 300. The ground level compensation Buck circuit accurately outputs the corresponding ground compensation voltage based on the PWM signal output by the DSP controller.

[0031] The output terminals of several charging output power circuits 7 are connected one-to-one with several Type-C interfaces 8. "Several" means one or more. In this embodiment, there are four charging output power circuits 7 and four Type-C interfaces 8.

[0032] Please refer to Figure 6In this embodiment, each charging output power circuit 7 is a DC-DC converter and PD protocol controller circuit of model RTQ7880 manufactured by Richtek Technology Co., Ltd. The RTQ7880 integrated chip can provide corresponding power output according to different requests from devices connected via the Type-C interface. A single port can support a maximum output of 100W, and all four ports can simultaneously support a maximum output of 150W.

[0033] Hub controller 6 communicates with several Type-C interfaces 8.

[0034] The power supply circuit 9 includes a Buck converter 91 and an LDO circuit 92. The input terminal of the Buck converter 91 is connected to the current output terminal of the input current detection circuit 3, and the output terminal of the Buck converter 91 is connected to the input terminal of the LDO circuit 92. The output terminal of the LDO circuit 92 is connected to the power input terminal of the microcontroller 4. The Buck converter is used to convert the voltage output from the current detection circuit 3 to a 5V voltage, and the LDO circuit 92 is used to convert the 5V voltage to a 3.3V voltage.

[0035] The ground level compensation Buck circuit 5, Hub controller 6, all charging output power circuits 7, Buck step-down circuit 91, and LDO circuit 92 are all connected to the same power ground. In this embodiment, the logic ground (from the vehicle host's SGND) and power ground of the high-power vehicle USB hub are separated.

[0036] This embodiment enables ground offset compensation for a 150W high-power USB hub. It effectively solves the problem of HUB controller data transmission port reference ground potential distortion caused by ground offset due to high current under high-power output conditions. This avoids abnormal phenomena such as frame loss and parsing errors in USB signal data packet transmission between the vehicle and the host computer, ensuring normal USB communication even with 150W high-power output.

[0037] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A high-power vehicle-mounted USB hub with a ground offset compensation function, characterized in that, The USB hub comprises a current input end, a current loop end, an input current detection circuit, a microcontroller, a ground level compensation Buck circuit, a plurality of charging output power supply circuits, and a plurality of Type-C interfaces same in number as the charging output power supply circuits; The current inflow end of the input current detection circuit is connected with the current input end, the current outflow end of the input current detection circuit is connected with the input end of the charging output power supply circuit respectively, the output end of the input current detection circuit is connected with the first input end of the microcontroller, and the input current detection circuit is used for detecting the input current of the vehicle-mounted USB hub and outputting a voltage signal proportional to the input current; The output end of the microcontroller is connected with the input end of the ground level compensation Buck circuit, and the microcontroller is used for calculating a ground compensation voltage according to the voltage signal output by the input current detection circuit and a preset ground impedance value, and generating a corresponding PWM signal according to the ground compensation voltage; The output end of the ground level compensation Buck circuit is connected with the current loop end, and the ground level compensation Buck circuit is used for outputting a ground compensation voltage to the current loop end according to the PWM signal, and the current loop end is connected with the power ground of the USB hub; The output end of the charging output power supply circuit is connected with the Type-C interface one by one.

2. The high power USB hub for automotive application as claimed in claim 1 wherein, The input current detection circuit comprises a current detection resistor and an amplification circuit; The first end of the current detection resistor is connected with the current input end, and the second end of the current detection resistor is connected with the input end of the charging output power supply circuit respectively; The input end of the amplification circuit is connected with the first end and the second end of the current detection resistor respectively, and the output end of the amplification circuit is connected with the first input end of the microcontroller.

3. The high power USB hub for automotive application as claimed in claim 2 wherein, The amplification circuit comprises an amplifier chip with a model of INA213, the IN+ pin of the amplifier chip is connected with the first end of the current detection resistor through a resistor R804, the IN- pin of the amplifier chip is connected with the second end of the current detection resistor through a resistor R802, and the OUT pin of the amplifier chip is connected with the first input end of the microcontroller.

4. The high power USB hub for automotive application as claimed in claim 1 wherein, The microcontroller is a DSP controller.

5. The high power USB hub for vehicle as claimed in claim 1 or 4 wherein, The second input end of the microcontroller is connected with the output end of the ground level compensation Buck circuit, and the microcontroller is used for carrying out closed-loop control on the PWM signal output by the microcontroller according to the output voltage of the ground level compensation Buck circuit.

6. The high power automotive USB hub of claim 1, wherein, The ground level compensation Buck circuit comprises a half-bridge driving circuit, a half-bridge circuit and a filter circuit; The input end of the half-bridge driving circuit is connected with the output end of the microcontroller, the output end of the half-bridge driving circuit is connected with the input end of the half-bridge circuit, the output end of the half-bridge circuit is connected with the input end of the filter circuit, and the output end of the filter circuit is connected with the current loop end.

7. The high power USB hub for automotive application as claimed in claim 6 wherein, The half-bridge drive circuit is composed of a UCC27282-Q1 half-bridge drive chip manufactured by Texas Instruments, and the upper half-bridge arm switch tube and the lower half-bridge arm switch tube of the half-bridge circuit are both NMOS tubes, and the filter circuit is an LC filter circuit.

8. The high power automotive USB hub of claim 1, wherein, Each of the charging output power supply circuits is a DC-DC converter and a PD protocol controller circuit produced by Lixil Technology Co., Ltd.

9. The high power automotive USB hub of claim 1, wherein, The vehicle-mounted USB hub comprises a power supply circuit, and the power supply circuit comprises a Buck step-down circuit and an LDO circuit. An input end of the Buck step-down circuit is connected with a current output end of the input current detection circuit, an output end of the Buck step-down circuit is connected with an input end of the LDO circuit, and an output end of the LDO circuit is connected with a power input end of the microcontroller.

10. The high power automotive USB hub of claim 1, wherein, The logic ground of the high-power vehicle-mounted USB hub is separated from the power ground.

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