USB cable with fast charging indicator

Abstract

We provide a USB cable with a fast charging indicator that allows you to reliably know when fast charging has started. [Solution] The USB cable with a fast charging indicator 1 has a voltage indicator unit installed in the USB connector 2 or in the middle of the USB cable, which consists of two light-emitting diodes 41 and 43 with a forward voltage of approximately 3V connected in series. This unit indicates that communication between the power supply and the terminal device has been established and that the fast charging function has been activated by a change in the brightness of the LEDs in the voltage status indicator unit. This function consists of two light-emitting diodes and one current-limiting resistor. At the standard USB supply voltage of 5V, the brightness of the light emission is extremely weak, but when the voltage changes to that of fast charging, the current increases, the brightness of the light-emitting diodes changes, and the fast charging function can be confirmed by the brightness of the voltage status indicator unit of the USB cable.

Description

Technical Field

[0001] The present invention relates to a cable for supplying power to a device in accordance with the USB standard.

Background Art

[0002] Conventionally, the USB (Universal Serial Bus) standard has a standard output voltage of 5V. In recent standard revisions, the power supplied using a USB cable has been increased. With USB PD (Power Delivery) defined by the USB Implementers Forum and USB Quick Charge (hereinafter referred to as USB QC) formulated by QUALCOMM, in addition to 5V, power supply has been extended to 9V, 12V, 20V required by the device side, and even up to 48V with USB PD.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In USB PD and USB QC, the terminal device is recognized by the communication function in the connection by the connector, and the supply voltage is determined by mutual communication. The prior art was developed for problems such as it is not immediately apparent that the charging voltage is different due to the difference in charging standards, or it is impossible to know how charging is performed in the connection with a dedicated charging cable without a communication function. However, this had the following drawbacks. (A) The price of the USB cable becomes high due to too many functions. (B) In the case of a cable between USB Type-Cs, since the current has a direction, the connection direction is limited. This invention was made to eliminate the aforementioned drawbacks. [Means for solving the problem]

[0005] In this invention, a voltage status display unit that focuses solely on voltage is installed at a location between one plug and the other plug of the USB cable. Specifically, a current-limiting resistor is used to bridge the power supply wiring between the positive and negative terminals of the USB cable. This resistor connects two light-emitting diodes (LEDs) with a forward voltage of approximately 3V, such as white or blue LEDs, in a polarity that allows them to emit light. For example, a 10kΩ resistor can be used for this connection. A diode, a semiconductor device, allows current to flow when the voltage is directed from the anode to the cathode. For example, if the voltage is gradually increased from 0V, the current will increase sharply from a certain voltage. The forward voltage is defined as the voltage required to overcome the barrier at the semiconductor junction. The forward voltage of a silicon diode is 0.6V, and the forward voltage of a red LED is approximately 2V. If two LEDs, each requiring a forward voltage of 3V to emit light, are connected in series, 6V is needed for them to light up. With the basic USB supply voltage of 5V, the light is extremely weak. When the power supply circuit recognizes and starts supplying a higher voltage than what the device requires, the voltage changes to 9V, 12V, or 20V. At these voltages, the LEDs light up brighter as the forward current increases, and the brightness changes significantly, allowing the user to clearly recognize that fast charging has started. It is also possible to use three LEDs with a forward voltage of 2V in series, but it is intentionally set to two. In reality, the USB voltage of DC 5V is further superimposed with noise and ripple from voltage conversion due to switching, which may result in the above voltage status indicator showing a weak illumination.

[0006] Because the display only responds to voltage, the direction in which the USB cable is connected is not restricted. Specifically, USB PD uses a USB Type-C connector, and there is no change in function regardless of which end is inserted into the power supply, and the voltage status display unit of this invention does not experience any functional problems. Furthermore, the USB cable connected to this USB PD can also be a USB extension cable with one end connected to another USB connector, and if the device side is set to use a dedicated connector for USB PD on a personal computer, the rapid charging status can be checked by using a USB extension cable with the added functionality of this invention.

[0007] On the other hand, in the case of USB QC, the power connector is USB Type A, and it is configured to use the most common connector. In this case, the USB connector on the power side of the cable according to this invention is a so-called male plug of USB Type A, and the device side is mostly USB Type C with fast charging functionality. However, it is not limited to this, and some devices are configured with USB Type B. In any case, in the case of the USB QC standard where the power side is USB Type A, it may be difficult to distinguish between a regular power supply that does not support this standard and a charging-only cable without communication functionality. The USB connector of this invention is also effective for identification purposes. [Effects of the Invention]

[0008] Based on the above, the USB cable with a rapid charging indicator according to this invention has the following effects. (i) After connecting the power supply and the device, the change in brightness of the LED on the voltage status indicator clearly indicates that the connection is correct and that rapid charging has started. (b) Since this voltage status display unit only requires connecting a minimum of three components in series between the power supply lines from the power supply unit to the USB, it can be set up as a display unit on any connector at the end of the USB cable, or even in between. (h) Because even very small chip components can be incorporated, they can be placed on the circuit board inside the connector, and the cost can be set up inexpensively. (ii) At 5V, the forward current flowing through the LED is weak, resulting in only slight illumination. However, due to the ripple superimposed on the power supply voltage, some power supplies can produce a weak illumination, allowing us to recognize that the power supply itself is available. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram illustrates the circuitry of the connector and display section of the present invention. A USB cable 1 with a fast charging indicator is described. The USB connector 2 on the power supply side is a connector called USB Type A or USB Type C, and the USB connector 3 on the other device side is mostly USB Type C, and the two are connected by a cable containing a minimum number of conductors to add communication functionality. When using a USB Type A connector, the conductors involved in power supply consist of a positive VBUS line 11 and a negative GND line 14, and the other two are D- line 12 and D+ line 13 for communication, for a total of four lines. In the case of a USB Type C to USB Type C cable, the standard consists of five lines in total, with the above two being D- line 12 and D+ line 13 for communication, plus an additional cc line. Furthermore, in the case of a charging-only cable, the D- line 12 and D+ line 13 are omitted, and a total of three lines, consisting of the positive VBUS line 11, the negative GND line 14, and the cc line, is considered the minimum configuration to support USB PD fast charging. The voltage status indicator unit 4 is connected to the conductors 11 and 14. The current flowing from the positive terminal to the negative terminal changes according to the supplied voltage, and the current increases significantly when the forward voltage is approximately 3V, causing it to light up brightly and significantly changing its brightness. The voltage status indicator unit 4 has a first LED 41, a second LED 43, and a current limiting resistor 42 connected in series between them. In this example, a 10kΩ current limiting resistor is used. In Figure 1, the voltage status indicator unit 4 is located inside the USB connector 2 on the power supply side, but it may also be located inside the USB connector 3 on the device side, or even in the middle of the cable.

[0010] [Figure 2] This diagram illustrates the LEDs in part 5 of the USB connector of the present invention. It shows an example where only the tips of the bullet-shaped LEDs 51 and 52, which are attached to the USB connector as the voltage status indicator of this invention, are exposed from the resin molding. The rest of the LEDs, the current limiting resistor, and the wiring are embedded within the resin molding. Although this connector is described as a USB Type A, it can also be used with the slightly smaller USB Type C. [Modes for carrying out the invention]

[0011] The present invention has the following structure. Two LEDs with a forward voltage of approximately 3V, such as white or blue LEDs, are connected as a bridge between the positive and negative power supply wires inside the USB cable, separated by a current-limiting resistor, in a polarity that allows them to emit light. For example, a 10kΩ resistor can be used for this resistor. This display unit, for example, is made of transparent resin if it is the connector part, and the two LEDs and resistor are added to the synthetic resin molded part at the connection point between the connector part and the cable part and molded as a single unit. Alternatively, if it is a bullet-shaped LED, it may be built into the connector part by molding it so that only the tip protrudes, or it may be provided by integrally molding it with transparent resin in the middle of the cable. [Examples]

[0012] Figure 1 shows an example. It shows that a voltage status indicator consisting of two LEDs and one resistor is located inside one of the USB connectors. It is preferable to expose the tips of the LEDs or to mold the connector with transparent resin. Figure 1 shows the difference in cable signal lines between USB Type A and USB Type C connectors on the power supply side. For USB Type A, the standard enabling fast charging is USB QC, and the cable consists of four wires, including the communication line. On the other hand, for USB Type C, the standard is USB PD, and to support minimal fast charging according to this standard, the positive terminal (V) BUSIn addition to the power line (V line) and the negative pole (GND line), it consists of three communication lines cc lines. When supporting data communication, two communication lines (D+, D−) are added to this, resulting in a five-line configuration. In any case, since the voltage state display unit is connected to the power line, it is merely displaying the voltage of the final state determined by the communication result through the change in the brightness of the LED.

Industrial Applicability

[0013] In the future, with the expansion of USB PD, the power supply side is regarded as the "source" and the power receiving side as the "sink", and for some devices, it is said to be a standard that can be either the source or the sink. The cable used also requires bidirectionality without limiting the power conduction direction, and this invention has the potential to be widely used in future in-house DC power supply. The voltage state display unit used for this rapid charging display can be used not only for the cable but also for the state display on the power supply side. In USB PD, since it is not output from the power supply side until it is connected, it is also effective for the state display of power supply. The voltage state display unit is currently used as the display inside the USB cable, but by itself, with an explanation, it may also be in the power supply device.

Explanation of Signs

[0014] 1 USB cable with rapid charging display of the present invention 11 V inside the USB cable BUS Line, positive pole 12 Data communication line D− inside the USB cable 13 Data communication line D+ inside the USB cable 14 GND line inside the USB cable, negative pole 15 Communication line cc in the case of USB Type-C 2 Connector part of USB Type-A or USB Type-C 3 Connector part of USB Type-C 4 Circuit part of the voltage state display unit 41 First LED of the voltage state display unit 42 Also current limiting resistor 43 Also second LED 5. USB Type-A connector with fast charging indicator. 51 First LED of the voltage status display unit 52 Second LED of the voltage status display unit 53 Cable section

Claims

[Claim 1] In a USB cable that conforms to the USB standard and connects a device to a power supply that can change the supply voltage according to the device's requirements, A voltage status indicator is placed at either the power supply side or the device side connector, or in an intermediate region between them, bridging the gap between the positive and negative terminals of the power supply line within the cable. This indicator consists of two light-emitting diodes with a forward voltage of approximately 3V connected in series with a current-limiting resistor. A USB cable with a rapid charging indicator, characterized in that it displays the rapid charging status by a voltage status display unit that changes the brightness of a light-emitting diode by increasing the current and transitioning to a strong light-emitting state when the forward voltage of the light-emitting diode is exceeded by a change in the supply voltage.

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