Standby low-power consumption circuit of USB socket

Abstract

The utility model discloses a standby low power consumption circuit of a universal serial bus (USB) socket, an input end of the standby low power consumption circuit is connected with alternating current commercial power, an output end of the standby low power consumption circuit is connected with a USB interface, the standby low power consumption circuit comprises a power supply circuit, a low standby power consumption primary side control chip, a transformer and a synchronous rectification chip, rectifying and filtering the standby low-power-consumption circuit; a primary winding of the transformer is connected with the power supply circuit, a secondary winding of the transformer is connected with the synchronous rectification chip, and a power supply pin of the low standby power consumption primary side control chip is connected with an auxiliary winding of the transformer; and a pin of the low standby power consumption primary side control chip is connected with the power supply circuit. According to the utility model, the low-power-consumption primary side control chip with low standby power consumption and the synchronous rectification chip are adopted, and the circuit structure is optimized, so that the standby power consumption of the USB socket circuit is less than 100mw.

Description

Technical Field

[0001] The utility model relates to the technical field of sockets and electronic circuits, in particular to a standby low-power consumption circuit of a USB socket. Background Art

[0002] In modern society, smart devices are widely popularized. Most smart devices (such as mobile phones, tablets, speakers, etc.) need to be charged. Except for some smart devices (such as mobile phones and tablets) equipped with charging heads, most other smart devices are not equipped with charging heads, but only USB charging cables. Therefore, users have an increasing demand for sockets with USB interfaces.

[0003] The socket has a USB interface. For safety certification, a USB smart identification chip is usually installed inside. In order to meet the charging needs of the USB interface, the AC mains is rectified and stepped down to a suitable voltage. The electrical components in the socket will also consume energy when the USB interface is not in use. Generally, the standby power consumption of a socket with a USB interface is about 0.8W-1W. Households often install USB sockets or USB socket panels, and the energy consumed over the years is also very huge. At the same time, the current international power switch energy efficiency standard is the 6-level standard. Efforts to research and develop Chinese products to meet or even exceed international standards are also the direction of research and development personnel. Utility Model Content

[0004] The utility model aims to provide a low-power standby circuit for a USB socket, which adopts a low-power primary side control chip and a synchronous rectification chip for standby low power consumption, optimizes the circuit structure, and makes the standby power consumption of the USB socket circuit less than 100mw.

[0005] The above technical purpose of the utility model is achieved through the following technical solutions: a standby low-power consumption circuit of a USB socket, the input end of the standby low-power consumption circuit is connected to the AC mains, and the output end is connected to the USB interface, including a power supply circuit, a low standby power consumption primary side control chip, a transformer and a synchronous rectification chip, the input end of the power supply circuit is connected to the AC mains to perform rectification and filtering for the standby low-power consumption circuit; the transformer includes a primary winding, a secondary winding and an auxiliary winding, the primary winding is linearly associated with the secondary winding, and the secondary winding is linearly associated with the auxiliary winding; the primary winding of the transformer is connected to the power supply circuit, the secondary winding of the transformer is connected to the synchronous rectification chip, the power pin of the low standby power consumption primary side control chip is connected to the auxiliary winding of the transformer; the pin of the low standby power consumption primary side control chip is connected to the power supply circuit.

[0006] By adopting the above technical solution, the power supply circuit rectifies and filters the input AC power, the transformer steps down the voltage and outputs it, the synchronous rectification chip rectifies the stepped-down power supply and outputs it to the USB interface, and at the same time, the low standby power consumption primary control chip controls the transformer's stepped-down power supply to output constant voltage and constant current, the power pin of the low standby power consumption primary control chip is connected to the auxiliary winding of the transformer, the auxiliary winding of the transformer and the secondary winding of the transformer are mutually inductive, when there is current in the secondary winding circuit, the auxiliary winding has an induced current, the low standby power consumption primary control chip has a set voltage, when the voltage on the auxiliary winding side is lower than the set voltage, the chip is turned off to reduce no-load power consumption.

[0007] The utility model is further configured as follows: it also includes a USB identification chip, a power pin of the USB identification chip is connected to the output end of the standby low power consumption circuit, and a communication pin of the USB identification chip is connected to the USB interface.

[0008] By adopting the above technical solution, the USB identification chip has a built-in charging protocol, which can automatically identify the type of charging device and match the appropriate charging mode with the device through the corresponding USB charging protocol.

[0009] The utility model is further configured as follows: the synchronous rectification chip is a PN8306H chip.

[0010] By adopting the above technical solution, the PN8306H chip has a built-in power MOSFET with extremely low voltage drop, which can improve the current output capability and enhance the power conversion efficiency. When the chip power supply voltage reaches 3.0V, the PN8306H starts to work, and when the chip power supply voltage drops to 2.7V, the chip stops working, reducing no-load power consumption and achieving low standby power consumption.

[0011] The utility model is further configured as follows: pins 5, 6, 7 and 8 of the PN8306H chip are connected to the negative output terminal of the secondary winding of the transformer, pin 4 of the PN8306H chip is connected to the positive output terminal of the secondary winding of the transformer, and pins 1, 2 and 3 of the PN8306H chip are connected to the ground point.

[0012] By adopting the above technical solution, pins 5, 6, 7 and 8 of the PN8306H chip are the chip power MOSFET drain pin outputs, pin 4 is the power pin, and the built-in power MOSFET of the chip PN8306H synchronously rectifies the current output by the secondary winding of the transformer.

[0013] The utility model is further configured as follows: the positive terminal of the auxiliary winding of the transformer is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the positive electrode of the diode D2, and the negative electrode of the diode D2 is connected to the power pin of the low standby power consumption primary side control chip.

[0014] By adopting the above technical solution, the low-power primary side control chip adopts high-voltage startup technology when starting, adopts a biased auxiliary source for power supply, and the biased auxiliary circuit current is extremely small, thereby achieving low power consumption of the power supply.

[0015] The utility model is further configured as follows: the power supply pin of the low standby power consumption primary side control chip is externally connected to one end of a capacitor C2, and the other end of the capacitor C2 is grounded.

[0016] By adopting the above technical solution, capacitor C2 not only serves as a decoupling capacitor to filter and stabilize voltage, but also charges the capacitor to quickly start the chip in the high-voltage startup technology.

[0017] The utility model is further configured as follows: the low standby power consumption primary side control chip model is PN8680P.

[0018] By adopting the above technical solutions, the chip PN8680P integrates an ultra-low standby power consumption primary-side controller and a 650V high avalanche capability intelligent power MOSFET. The chip PN8680P can achieve a chip no-load loss (230VAC) of less than 50mW.

[0019] The utility model is further configured as follows: the FB pin of the PN8680P chip is connected between the voltage-dividing resistors R7 and R8 of the auxiliary winding of the transformer, and the CS pin of the PN8680P chip is connected to the voltage-dividing resistor R4.

[0020] By adopting the above technical solution, the PN8680P chip samples the auxiliary winding side signal in the FB pin to achieve constant voltage and constant current output of the circuit; the PN8680P chip detects the current of the built-in power tube of the chip through the voltage divider resistor of the CS pin.

[0021] The utility model is further configured as follows: the power supply circuit includes a rectifier bridge circuit.

[0022] By adopting the above technical solution, the rectifier bridge rectifies the AC mains.

[0023] The utility model is further configured as follows: the USB identification chip communication pin is connected to the USB interface and / or the USB_TYPE_C interface.

[0024] By adopting the above technical solution, the output end of the low-power standby circuit can be connected to the USB interface or the USB_TYPE_C interface or both can be connected at the same time.

[0025] Compared with the prior art, the utility model adopts a low-power primary side control chip with low standby power consumption and a low-power synchronous rectification chip, optimizes the circuit structure, makes the standby power consumption of the USB socket circuit less than 100mw, and reduces energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a principle block diagram of a low-power standby circuit of a USB socket in an embodiment of the utility model.

[0027] Figure 2 It is a connection principle diagram of a low-power standby circuit of a USB socket in an embodiment of the utility model.

[0028] Figure 3 This is a USB socket energy efficiency test chart.

[0029] Figure 4 This is a connection diagram of the chip PN8680P in the embodiment of the utility model.

[0030] Figure 5 This is a connection diagram of chip PN8306H in an embodiment of the present utility model.

[0031] In the figure: 1. power supply circuit; 2. low standby power consumption primary side control chip; 3. transformer; 301. primary winding; 302. secondary winding; 303. auxiliary winding; 4. synchronous rectification chip; 5. USB identification chip. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model; it is obvious that the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the utility model without making creative work are within the scope of protection of the utility model.

[0033] like Figure 1 , Figure 2 As shown, the utility model discloses a low-power standby circuit of a USB socket, the input end of the low-power standby circuit is connected to the AC mains, and the output end is connected to the USB interface. The low-power standby circuit includes a power supply circuit 1, a low standby power primary control chip 2, a transformer 3, a synchronous rectification chip 4 and a USB identification chip 5. The input end of the power supply circuit 1 is connected to the AC mains, and the output end is connected to the primary winding 301 of the transformer 3, which is a rectifier and filter for the low-power standby circuit; each pin of the low standby power primary control chip 2 is connected to the power supply circuit 1, wherein the low standby power The power pin of the primary side control chip 2 is connected to the primary auxiliary winding 303 of the transformer 3; the primary winding 301 of the transformer 3 is connected to the power circuit 1, and the secondary winding 302 of the transformer 3 is connected to the USB identification chip 5; the low standby power consumption primary side control chip 2 is set with a power shutdown voltage VDDoff, and when the bias circuit on the auxiliary winding 303 side is lower than the set value, the chip is turned off to reduce power consumption; before the chip is started, the bias circuit on the auxiliary winding 303 side has a 2.0mA current to power the internal circuit of the chip and charge the external capacitor for quick startup.

[0034] In this embodiment, the low standby power consumption primary side control chip 2 adopts the model PN8680P, and may also be replaced by a chip with the same or similar function.

[0035] like Figure 4 As shown, the chip PN8680P integrates an ultra-low standby power consumption primary-side controller and an intelligent power MOSFET, wherein the MOSFET has a high avalanche capability of 650V; the chip PN8680P has a built-in high-voltage startup circuit, which can achieve a chip no-load loss of less than 50mW (230VAC); the power pin VDD (pin 1) of the chip PN8680P is connected to the primary auxiliary winding 303 of the transformer 3, and the primary auxiliary winding 303 of the transformer 3 supplies power to the chip PN8680P; further, one end of the primary auxiliary winding 303 of the transformer 3 is connected to the resistor R6 and then to the positive electrode of the diode D2, and the negative electrode of the diode D2 is connected to the power pin of the chip PN8680P, and the power pin of the chip PN8680P is connected in parallel with the capacitor C2.

[0036] The chip PN8680P has a high-voltage startup function. A 2.0mA current source can start the chip PN8680P to achieve low loss. The intelligent power MOSFET Drain end pin SW (pin 5, pin 6, pin 7 and pin 8) of the chip PN8680P is connected to the primary winding 301 of the transformer 3. The current detection pin CS (pin 4) of the chip PN8680P is connected to the voltage-dividing resistors R4 and R5. The feedback pin FB (pin 3) of the chip PN8680P is connected between the voltage-dividing resistors R7 and R8 connected to one end of the primary auxiliary winding 303 of the transformer 3. The signal collected at the end of the primary auxiliary winding 303 of the transformer 3 is a constant voltage and constant current output of the circuit; the chip detects the current of the built-in power tube of the chip through the resistance of the CS pin.

[0037] like Figure 2 , Figure 5As shown, in this embodiment, a chip PN8306H is connected between the secondary winding 302 of the transformer 3 and the USB identification chip 5. The chip PN8306H is used to replace the rectifier diode in the power supply circuit 1. The chip PN8306H includes a synchronous rectifier controller and a high avalanche capability power MOSFET. The loss of a general switching power supply is mainly composed of three parts: the loss of the power switch tube, the loss of the high-frequency transformer 3, and the loss of the output rectifier tube. In the case of low voltage and high current output, the conduction voltage drop of the rectifier diode is relatively high, and the loss of the output rectifier tube is particularly prominent. The fast recovery diode (F RD) or superfast recovery diode (SRD) can reach 1.0-1.2V. Even if a low-voltage-drop Schottky diode (SBD) is used, a voltage drop of about 0.6V will be generated, which leads to increased rectification loss. In this embodiment, the chip PN8306H is used to replace the traditional rectifier diode or Schottky diode. The built-in power MOSFET of PN8306H has a very low voltage drop, which can improve the current output capability and the conversion efficiency, so that the system efficiency can meet the 6-level energy efficiency standard. When used with the chip PN8680P, the standby circuit of the utility model can be further put into low-power standby mode.

[0038] The power pin VDD (pin 4) of the chip PN8306H is connected to the positive terminal of the secondary winding 302 of the transformer 3, and the power MOSFET DRAIN pin SW (pins 5, 6, 7 and 8) of the chip PN8306H is connected to the negative terminal of the secondary winding 302 of the transformer 3. The chip PN8306H outputs a rectified DC voltage to power the USB identification chip 5 and the USB port; at the same time, the chip PN8306H starts working when the voltage at the power pin VDD reaches 3.0V, and stops working when the voltage at the power pin VDD is as low as 2.7V to reduce standby power consumption.

[0039] like Figure 2 As described, the USB identification chip 5 is respectively connected to the output end of the low-power standby circuit and the USB interface. The USB identification chip 5 has a built-in charging protocol, which can automatically identify the type of charging device and match the appropriate charging mode with the device through the corresponding USB charging protocol. The USB interface can be a universal USB port or a USB Type-C port.

[0040] The socket with built-in standby low power consumption circuit is tested for electrical performance in the testing agency, such as Figure 3 As described, when the socket is at 230V 50HZ, the power consumption is 0.062W when no-load and the standby power consumption is less than 0.1W.

[0041] The utility model adopts a low-power primary side control chip with low standby power consumption and a low-power synchronous rectification chip, optimizes the circuit structure, makes the standby power consumption of the USB socket circuit less than 100mw, and reduces energy consumption.

[0042] The above description is only a preferred embodiment of the present utility model, so all equivalent changes or modifications made according to the structure, features and principles described in the scope of the present utility model patent application are included in the scope of the present utility model patent application.

Claims

1. A standby low power consumption circuit for a USB socket, wherein the input end of the standby low power consumption circuit is connected to the AC mains, and the output end is connected to the USB interface, characterized in that: The invention comprises a power supply circuit (1), a low standby power consumption primary side control chip (2), a transformer (3) and a synchronous rectification chip (4); the input end of the power supply circuit (1) is connected to an AC mains to perform rectification and filtering for the standby low power consumption circuit; the transformer (3) comprises a primary winding (301), a secondary winding (302) and an auxiliary winding (303); the primary winding (301) is linearly associated with the secondary winding (302), and the secondary winding (302) is linearly associated with the auxiliary winding (303); the primary winding (301) of the transformer (3) is connected to the power supply circuit (1), the secondary winding (302) of the transformer (3) is connected to the synchronous rectification chip (4), the power supply pin of the low standby power consumption primary side control chip (2) is connected to the auxiliary winding (303) of the transformer (3); and the pin of the low standby power consumption primary side control chip (2) is connected to the power supply circuit (1).

2. The low power consumption standby circuit of a USB socket according to claim 1, characterized in that: It also comprises a USB identification chip (5), wherein a power pin of the USB identification chip (5) is connected to the output end of the standby low power consumption circuit, and a communication pin of the USB identification chip (5) is connected to a USB interface.

3. The low power consumption standby circuit of a USB socket according to claim 1, characterized in that: The synchronous rectification chip (4) is a PN8306H chip.

4. The low power consumption standby circuit of a USB socket according to claim 3, characterized in that: Pins 5, 6, 7 and 8 of the PN8306H chip are connected to the negative output end of the secondary winding (302) of the transformer (3), pin 4 of the PN8306H chip is connected to the positive output end of the secondary winding (302) of the transformer (3), and pins 1, 2 and 3 of the PN8306H chip are connected to the ground point.

5. The low power consumption standby circuit of a USB socket according to claim 1, characterized in that: The positive terminal of the auxiliary winding (303) of the transformer (3) is connected to one end of a resistor R6, the other end of the resistor R6 is connected to the positive electrode of a diode D2, and the negative electrode of the diode D2 is connected to the power pin of a low standby power consumption primary side control chip (2).

6. The low power consumption standby circuit of a USB socket according to claim 5, characterized in that: The power supply pin of the low standby power consumption primary side control chip (2) is externally connected to one end of a capacitor C2, and the other end of the capacitor C2 is grounded.

7. The low power consumption standby circuit of a USB socket according to claim 6, characterized in that: The model of the low standby power consumption primary side control chip (2) is PN8680P.

8. The low power consumption standby circuit of a USB socket according to claim 7, characterized in that: The FB pin of the PN8680P chip is connected between the voltage-dividing resistors R7 and R8 of the auxiliary winding (303) of the transformer (3), and the CS pin of the PN8680P chip is connected to the voltage-dividing resistor R4.

9. The low power consumption standby circuit of a USB socket according to claim 1, characterized in that: The power supply circuit (1) comprises a rectifier bridge circuit.

10. The low power consumption standby circuit of a USB socket according to claim 2, characterized in that: The communication pin of the USB identification chip (5) is connected to the USB interface and / or the USB_TYPE_C interface.

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