CN221977393U - Electronic tag Ra circuit - Google Patents
Electronic tag Ra circuit Download PDFInfo
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- CN221977393U CN221977393U CN202420549366.3U CN202420549366U CN221977393U CN 221977393 U CN221977393 U CN 221977393U CN 202420549366 U CN202420549366 U CN 202420549366U CN 221977393 U CN221977393 U CN 221977393U
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- 230000003313 weakening effect Effects 0.000 abstract description 14
- 230000000694 effects Effects 0.000 description 8
- 239000003550 marker Substances 0.000 description 7
- 230000005540 biological transmission Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
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Abstract
The utility model discloses an electronic tag Ra circuit, which relates to the field of Ra circuit design, and comprises: the switching tube, the first resistor and the negative-pressure charge pump; the drain electrode of the switch tube is connected with the VCONN pin of the electronic tag chip; setting a first resistor at least between the source of the switching tube and the ground; the grid electrode of the switch tube is connected with the negative-pressure charge pump; the electronic tag chip is carried on the USB Type-C cable; when the VCONN pin and the VBUS pin of the electronic tag chip in the USB Type-C cable are in short circuit, voltage drop is generated on the first resistor by current flowing to the ground from the VCONN pin, so that the gate-source voltage difference of the switching tube is increased negatively, and the resistance of the switching tube is increased. The utility model can improve the pressure resistance of the Ra circuit before weakening at low cost and avoid damage of the Ra circuit.
Description
Technical Field
The utility model relates to the field of Ra circuit design, in particular to an electronic tag Ra circuit.
Background
Compared with the traditional USB interface, the USB Type-C interface has a thinner structural design, a faster data transmission rate and a higher power transmission capability. In addition, the USB Type-C interface supports double-sided forward and backward insertion, and brings extremely convenient use experience for consumers. The USB Type-C interface has gained rapid popularity in the consumer electronics field since its introduction.
The USB Type-C protocol explicitly specifies that a special electronic tag chip (E-marker) must be mounted on the USB Type-C cable supporting the current carrying capability above 3A or the data transmission rate above USB3.0, so as to ensure the reliability and security of high-power transmission and high-rate data transmission. Meanwhile, after the E-marker is identified to be electrified, the Ra circuit is weakened within 1.2s, namely the resistance value of the Ra circuit about 1kΩ is increased, so that the E-marker in a non-communication state consumes less than 20mW.
A conventional Ra circuit implementation is shown in fig. 1. The N-type transistor M0 functioning as a switch is a depletion transistor or a self-sign transistor, and its on threshold voltage is a negative value. A resistor R0 of 1kΩ is connected in series between the VCONN pin and the drain of the N-type transistor M0. The gate of the N-type transistor M0 is connected with a negative-pressure charge pump. Before the negative-pressure charge pump is started, the voltage of the grid electrode of the N-type transistor M0 is zero, and at the moment, the N-type transistor M0 is conducted, so that a 1k omega resistance is displayed between VCONN and GND; when the negative-pressure charge pump is started, the grid voltage of the N-type transistor M0 is lower than the threshold voltage of the N-type transistor M0, the N-type transistor M0 is turned off, a very large resistance is displayed between VCONN and GND, and weakening of an Ra circuit can be well achieved.
In order to further reduce the loss of the system, the Type-C protocol recommends that the voltage output of VCONN be turned off after the E-marker information access is completed, and PD (PowerDelivery) still can maintain normal communication and power transmission. Thus, the E-marker will be in a power down state, and a 1kΩ Ra circuit is reapplied between VCONN and GND. At this time, if the USB Type-C interface shakes, the VBUS pin at high voltage is shorted to the VCONN pin adjacent to the VBUS pin at the physical position, and this process is equivalent to directly powering up the VCONN pin to the corresponding high voltage, and the Ra circuit of the E-marker has not yet reached the point of weakening. The Ra circuit will be subjected to a large current and power before weakening. Taking VBUS at 48V as an example, the instant the VBUS pin shorts to the VCONN pin will have about 48mA current flowing through the Ra circuit, dissipating about 2.3W. This is extremely prone to damage to the Ra circuitry, leading to cable burnout and even safety accidents when severe. If the Ra circuit is designed with this current and power carrying capability, it tends to occupy a larger chip area, increasing the cost of the chip.
In summary, in the design of Ra circuits in E-markers, how to improve the voltage resistance before weakening the Ra circuits at low cost and prevent the Ra circuits from being damaged is a current urgent problem.
Disclosure of utility model
The utility model aims to provide an electronic tag Ra circuit, which is used for improving the pressure resistance of the Ra circuit before weakening at low cost and avoiding damage to the Ra circuit caused by loading high current and high power on the Ra circuit at the moment of short circuit between a high-voltage VBUS pin and an unpowered VCONN pin.
In order to achieve the above object, the present utility model provides the following solutions:
An electronic tag Ra circuit comprising: the switching tube, the first resistor and the negative-pressure charge pump;
the drain electrode of the switch tube is connected with the VCONN pin of the electronic tag chip; setting the first resistor at least between the source electrode of the switching tube and the ground; the grid electrode of the switching tube is connected with the negative-pressure charge pump; the electronic tag chip is carried on the USB Type-C cable;
When the VCONN pin and the VBUS pin of the electronic tag chip in the USB Type-C cable are in short circuit, the voltage drop of the current flowing from the VCONN pin to the ground is generated on the first resistor, so that the gate-source voltage difference of the switching tube is increased negatively, and the resistance of the switching tube is increased.
Optionally, the resistance of the first resistor ranges from 800 Ω to 1.2kΩ.
Optionally, the electronic tag Ra circuit further includes: a second resistor;
The second resistor is arranged between the drain electrode of the switch tube and the VCONN pin of the electronic tag chip.
Optionally, the total resistance of the first resistor and the second resistor ranges from 800 Ω to 1.2kΩ.
Optionally, the resistance of the first resistor is greater than the resistance of the second resistor.
Optionally, the resistance value of the first resistor is 1kΩ.
Optionally, the total resistance of the first resistor and the second resistor is 1kΩ.
Optionally, the switching tube is a depletion type switching tube.
According to the specific embodiment provided by the utility model, the utility model discloses the following technical effects:
The electronic tag Ra circuit of the present utility model includes: the switching tube, first resistance and negative pressure charge pump, set up first resistance at least between the source of switching tube and ground, when the VCONN pin of the electronic tag chip in the USB Type-C cable and VBUS pin short circuit, the VCONN is directly on to high pressure, the negative pressure charge pump still can't get the start, the electric current that flows to ground from the VCONN pin produces the pressure drop on first resistance, make the grid source voltage difference of switching tube increase negatively, the resistance of switching tube increases, the total resistance of Ra circuit grow, thus through the negative feedback effect of first resistance at the source, the withstand voltage before the weakening of Ra circuit has been improved to low cost, avoid the VBUS pin of high pressure to short circuit with the VCONN pin that does not go up, high current and high power load lead to the damage of Ra circuit on the Ra circuit, thereby reinforcing E-marker and USB Type-C cable use's security and reliability.
Drawings
In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic circuit diagram of a conventional Ra circuit;
Fig. 2 is a schematic circuit diagram of an Ra circuit of an electronic tag according to embodiment 1 of the present utility model;
fig. 3 is a schematic circuit diagram of an Ra circuit of an electronic tag according to embodiment 2 of the present utility model.
Symbol description:
N-type transistor-M0, 1kΩ resistor-R0, switch tube-M1, first resistor-R1, second resistor-R2.
Detailed Description
The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
The utility model aims to provide an electronic tag Ra circuit, which aims to improve the pressure resistance of the Ra circuit before weakening at low cost and avoid damage to the Ra circuit caused by loading high current and high power on the Ra circuit at the moment of short circuit between a high-voltage VBUS pin and an unpowered VCONN pin.
In order that the above-recited objects, features and advantages of the present utility model will become more readily apparent, a more particular description of the utility model will be rendered by reference to the appended drawings and appended detailed description.
Example 1
As shown in fig. 2, the electronic tag Ra circuit in this embodiment includes: the switching tube M1, the first resistor R1 and the negative-pressure charge pump.
The drain electrode of the switch tube M1 is connected with a VCONN pin of the electronic tag chip; setting the first resistor R1 at least between the source electrode of the switch tube M1 and the ground; the grid electrode of the switch tube M1 is connected with the negative-pressure charge pump; the electronic tag chip is carried on the USB Type-C cable. The switching tube M1 is used for realizing the on-off weakening of the Ra circuit; the first resistor R1 is responsible for the effect of extremely negative feedback.
When the VCONN pin and the VBUS pin of the electronic tag chip in the USB Type-C cable are in short circuit, voltage drop is generated on the first resistor R1 by current flowing to the ground GND from the VCONN pin, so that the gate-source voltage difference of the switching tube M1 is increased negatively, the resistance of the switching tube M1 is increased, the total resistance of the Ra circuit is increased, the negative feedback effect of the first resistor R1 at the source electrode is utilized to limit the maximum current flowing through the Ra circuit, the voltage resistance before weakening the Ra circuit is improved at low cost, and damage to the Ra circuit is avoided.
The negative-pressure charge pump is started within 1.2s of the power-on time of the VCONN pin, and negative voltage is generated and applied to the grid electrode of the MOS tube, so that the MOS tube is turned off or the resistance value is obviously increased, and the purpose of weakening the Ra circuit is achieved.
In one example, the first resistor R1 has a resistance range of [800Ω,1.2kΩ ]. For example, the resistance value of the first resistor R1 may be 1kΩ.
In one example, the switching tube is a high voltage depletion mode switching tube.
The working principle of the Ra circuit of the electronic tag of the present embodiment is described in further detail below to illustrate the effectiveness of the present embodiment.
When the VCONN pin of the electronic tag chip in the USB Type-C cable is short-circuited with the VBUS pin of the high voltage, the VCONN is directly electrified to the high voltage, the negative-pressure charge pump cannot be started yet, the grid voltage of the switching tube M1 is kept to be zero, the switching tube M1 is kept on, and current flows in from the VCONN pin, passes through the switching tube M1 and the first resistor R1 and flows to the ground GND. The voltage drop can be generated on the first resistor R1 by the current, so that the source voltage of the switching tube M1 is raised, the gate-source voltage difference of the switching tube M1 is increased negatively, the resistance value of the switching tube M1 is increased, the total resistance value of the Ra circuit is increased, and the current flowing through the Ra circuit is inhibited by negative feedback. The source voltage of the final switching transistor M1 is stabilized near |V th | by the negative feedback of the source, so that the current flowing through the Ra circuit is limited toWherein V th is the threshold voltage of the switching tube and is a negative value. Typically |v th | <5V, so the maximum current flowing through the Ra circuit is typically no more than 5mA, the dissipated power is no more than 48V x 5mA = 240mW. Compared with the traditional structure, the current and the dissipation power flowing through the Ra circuit are greatly reduced, the Ra circuit is easier to realize high voltage resistance and high reliability, and circuit damage before weakening of the Ra circuit can be avoided.
Example 2
As shown in fig. 3, the electronic tag Ra circuit of the present embodiment is different from the above embodiment 1 in that it further includes: and a second resistor R2. The second resistor R2 is arranged between the drain electrode of the switch tube M1 and the VCONN pin of the electronic tag chip.
The negative-pressure charge pump is started within 1.2s of the power-on time of VCONN, and negative voltage is generated and applied to the grid electrode of the switching tube M1, so that the switching tube M1 is turned off or the resistance value is obviously increased, and the purpose of weakening the Ra circuit is achieved. The first resistor R1 is responsible for the effect of extremely negative feedback.
In one example, the total resistance of the first resistor R1 and the second resistor R2 ranges from [800 Ω,1.2kΩ ], for example, the total resistance of the first resistor R1 and the second resistor R2 is 1kΩ.
The working principle of the Ra circuit of the electronic tag of the present embodiment is described in further detail below to illustrate the effectiveness of the present embodiment.
When the VCONN pin of the electronic tag chip in the USB Type-C cable is short-circuited with the VBUS pin of the high voltage, the VCONN is directly electrified to the high voltage, the negative-pressure charge pump cannot be started, the grid voltage of the switching tube M1 is kept to be zero, the switching tube M1 is kept on, and current flows in from the VCONN pin, passes through the second resistor R2, the switching tube M1 and the first resistor R1 and flows to GND. The voltage drop can be generated on the first resistor R1 by the current, so that the source voltage of the switching tube M1 is raised, the gate-source voltage difference of the switching tube M1 is increased negatively, the resistance value of the switching tube M1 is increased, and the total resistance value of the Ra circuit is increased. The source voltage of the final switching transistor M1 is stabilized near |V th | by the negative feedback of the source, so that the current flowing through the Ra circuit is limited toWherein V th is the threshold voltage of the depletion mode tube and is negative. Typically, |V th | <5V, so the maximum current flowing through the Ra circuit typically does not exceedThe dissipated power is not more thanBy setting the resistance value of the first resistor R1, the current and the dissipation power flowing through the Ra circuit can be greatly reduced compared with the conventional structure, and the Ra circuit is easier to realize high withstand voltage and high reliability.
The relation between the resistances of the first resistor R1 and the second resistor R2 is not limited, and the total resistance thereof may be maintained at [800Ω,1.2kΩ ]. In the extreme case, when the resistance value of the second resistor is small and is close to 0, that is, the circuit configuration shown in the above embodiment 1 can achieve the above-described effect as well. In order to achieve a better effect, the resistance value of the first resistor R1 is larger than that of the second resistor R2, and the larger the resistance value of the first resistor R1 is, the better.
All the embodiments are electronic tag Ra circuits based on source negative feedback, and the resistor in the Ra circuit or part of the resistor is connected between the source of the switch tube and the ground. By utilizing the negative feedback effect of the resistor on the source electrode, the maximum current flowing through the Ra circuit is limited, the voltage resistance of the Ra circuit before weakening is improved, and the damage of the Ra circuit caused by the high current and high power loaded on the Ra circuit when the VBUS pin and the VCONN pin of high voltage are in short circuit is avoided.
The principles and embodiments of the present utility model have been described herein with reference to specific examples, the above examples being provided only to assist in understanding the circuitry of the present utility model and its core ideas; also, it is within the scope of the present utility model to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the utility model.
Claims (8)
1. An electronic tag Ra circuit, comprising: the switching tube, the first resistor and the negative-pressure charge pump;
the drain electrode of the switch tube is connected with the VCONN pin of the electronic tag chip; setting the first resistor at least between the source electrode of the switching tube and the ground; the grid electrode of the switching tube is connected with the negative-pressure charge pump; the electronic tag chip is carried on the USB Type-C cable;
When the VCONN pin and the VBUS pin of the electronic tag chip in the USB Type-C cable are in short circuit, the voltage drop of the current flowing from the VCONN pin to the ground is generated on the first resistor, so that the gate-source voltage difference of the switching tube is increased negatively, and the resistance of the switching tube is increased.
2. The electronic tag Ra circuit of claim 1, wherein the first resistor has a resistance value in the range of [800 Ω,1.2kΩ ].
3. The electronic tag Ra circuit of claim 1, further comprising: a second resistor;
The second resistor is arranged between the drain electrode of the switch tube and the VCONN pin of the electronic tag chip.
4. The electronic tag Ra circuit of claim 3, wherein the total resistance of the first resistor and the second resistor has a resistance value in the range of [800 Ω,1.2kΩ ].
5. The electronic tag Ra circuit of claim 4, wherein the first resistor has a resistance greater than a resistance of the second resistor.
6. The electronic tag Ra circuit of claim 2, wherein the first resistor has a resistance of 1kΩ.
7. The electronic tag Ra circuit of claim 4, wherein the first resistor and the second resistor have a total resistance of 1kΩ.
8. The electronic tag Ra circuit of claim 1, wherein the switching tube is a depletion-mode switching tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202420549366.3U CN221977393U (en) | 2024-03-21 | 2024-03-21 | Electronic tag Ra circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202420549366.3U CN221977393U (en) | 2024-03-21 | 2024-03-21 | Electronic tag Ra circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN221977393U true CN221977393U (en) | 2024-11-08 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202420549366.3U Active CN221977393U (en) | 2024-03-21 | 2024-03-21 | Electronic tag Ra circuit |
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| Country | Link |
|---|---|
| CN (1) | CN221977393U (en) |
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2024
- 2024-03-21 CN CN202420549366.3U patent/CN221977393U/en active Active
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