CN211457377U - double-SIM card switching circuit for gateway - Google Patents
double-SIM card switching circuit for gateway Download PDFInfo
- Publication number
- CN211457377U CN211457377U CN202020559052.3U CN202020559052U CN211457377U CN 211457377 U CN211457377 U CN 211457377U CN 202020559052 U CN202020559052 U CN 202020559052U CN 211457377 U CN211457377 U CN 211457377U
- Authority
- CN
- China
- Prior art keywords
- switching
- chip
- voltage
- sim card
- sim
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Telephone Function (AREA)
Abstract
The utility model discloses a double SIM card switching circuit for gateway, including first SIM cassette, second SIM cassette, switching chip and level shift circuit, the switching chip is used for the SIM interface of wireless baseband chip and the connection, the switching of first SIM cassette, second SIM cassette, the SIM interface of wireless baseband chip works in first voltage; the level conversion circuit is used for level conversion of interfaces of the switching chip and the main control chip, the interface level of the switching chip is configured to be a first voltage, the interface level of the main control chip is configured to be a second voltage, and lossless transmission of signals between the switching chip and the main control chip is achieved through bidirectional level conversion or unidirectional level conversion between the first voltage and the second voltage. The utility model discloses realize the connection and the switching of wireless baseband chip and two independent SIM cassette, and match through level conversion, guarantee the normal switching of SIM card and stabilize the reading and writing.
Description
Technical Field
The utility model relates to a SIM card extension field, in particular to two SIM card switching circuits for gateway.
Background
At present, many gateway devices adopt communication modules to build own network communication, but the interfaces of the existing communication modules are designed based on one SIM card, namely, only one SIM card can be inserted into one communication module. However, in practical use, a lot of scenes need data to be disaster-backed, that is, when one SIM card is owed or otherwise abnormal, another SIM card can perform data exchange.
SUMMERY OF THE UTILITY MODEL
In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a dual SIM card switching circuit for a gateway, which can operate stably to meet the application requirements of disaster recovery.
In order to achieve the above object, the present invention provides a dual SIM card switching circuit for a gateway, comprising a first SIM card holder, a second SIM card holder, a switching chip and a level shifter,
the switching chip is used for connecting and switching an SIM interface of the wireless baseband chip with the first SIM card holder and the second SIM card holder, and the SIM interface of the wireless baseband chip works at a first voltage;
the level conversion circuit is used for interface level conversion of a switching chip and a main control chip, wherein the interface level of the switching chip is configured to be a first voltage, and the interface level of the main control chip is configured to be a second voltage;
the level conversion circuit comprises a unidirectional level conversion circuit unit and a plurality of bidirectional level conversion circuit units;
the bidirectional level conversion circuit unit comprises a first NMOS transistor, a first resistor and a second resistor; the source electrode of the first NMOS tube is connected with the switching chip and is pulled up to a first voltage through a first resistor; the drain electrode of the first NMOS is connected with the main control chip and is pulled up to a second voltage through a second resistor; the grid electrode of the first NMOS tube is connected with a first voltage;
the unidirectional level conversion circuit unit comprises a second NMOS tube, a third resistor, a fourth resistor and a fifth resistor, wherein the source electrode of the second NMOS tube is grounded, and the drain electrode of the second NMOS tube is connected with the switching chip and is pulled up to a first voltage through the third resistor; and the grid electrode of the second NMOS tube is connected with the main control chip through a fourth resistor and is grounded through a fifth resistor.
Further, the model of the switching chip is TXS 02326A.
Further, the first voltage is 1.8V, and the second voltage is 3.3V.
Further, the number of the bidirectional level shift circuit units is 2.
Further, the model of the first NMOS transistor and the second NMOS transistor is AP2318 GEN.
The technical effects of the utility model:
the utility model discloses a two SIM card switching circuits for gateway realizes the connection and the switching of wireless baseband chip and two independent SIM cassettes, and matches through level conversion, guarantees the normal switching of SIM card and stabilizes the reading and writing.
Drawings
Fig. 1 is a circuit diagram of a dual-path SIM card switching circuit according to an embodiment of the present invention.
Detailed Description
To further illustrate the embodiments, the present invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. With these references, one of ordinary skill in the art will appreciate other possible embodiments and advantages of the present invention. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.
The present invention will now be further described with reference to the accompanying drawings and detailed description.
As shown in fig. 1, the utility model discloses a two SIM card switching circuits for gateway, including switching chip U100, first SIM cassette J100, second SIM cassette J102 and level conversion circuit.
In this embodiment, the switching chip U100 employs TXS02326A, where TXS02326A is a customized device for expanding a single SIM/UICC interface to support two SIM/UICC interfaces, and is a dual-power 2:1 intelligent identity module (SIM) card multiplexer/converter with an automatic detection and slot-dedicated dual-channel low dropout regulator (LDO), and includes a set of management interfaces, a set of SIM card input interfaces, and two sets of SIM card output interfaces, where the two sets of SIM output interfaces are electrically connected to a first SIM card socket and a second SIM card socket, respectively; and the SIM card input interface is used for being connected with the communication module. The switching chip U100 has two power supply pins: VDDIO and VBAT. In this embodiment, VBAT is connected to the system power supply, the voltage is 3.3V, VDDIO sets the reference voltage for the baseband chip interface and operates at 1.8V.
The management interface includes a reset interface and an I2C interface. The I2C interface includes signals SCK and SDA corresponding to the 23 rd pin and the 24 th pin of the switching chip U100, respectively, and the reset interface is a signal RSTX (pin 2) of the switching chip U100. The SIM card input interface includes signals SIM _ RST (pin 16), SIM _ CLK (pin 17), and SIM _ DATA (pin 18).
The SIM card output interface comprises: a first SIM card output interface (including power supply SIM _ VCC1, signal SIM _ RST1, SIM _ CLK1, and SIM _ DATA1) and a second SIM card output interface (including power supply SIM _ VCC2, signal SIM _ RST2, SIM _ CLK2, and SIM _ DATA 2).
In this embodiment, the switching chip U100 implements connection between a wireless baseband chip (communication module) and two independent SIM card sockets, and is switched and controlled by the main control chip.
In this embodiment, the SIM card interface of the wireless baseband chip operates at a voltage of 1.8V, and in order to match this, the interface voltage of the switching chip is configured to 1.8V through VDDIO; therefore, the interface voltage of the management interface of the switching chip U100 is kept consistent with VDDIO, and is also configured to be 1.8V.
In this embodiment, the main control chip operates at a voltage of 3.3V, so that the high level of the management interface at the main control chip end is mismatched with the high level of the management interface at the switch chip end, and if a direct connection mode is adopted, the transmission signal cannot be correctly identified, so that matching needs to be performed through the level conversion circuit.
The I2C interface includes signals SCK and SDA, where SDA is a bidirectional signal, and in this embodiment, both signals SCK and SDA configure a bidirectional level shift circuit unit.
In this embodiment, taking the bidirectional level shift circuit unit corresponding to the signal SCK as an example, the bidirectional level shift circuit unit includes an NMOS transistor Q100 and a resistor R118, the drain of the NMOS transistor Q100 is connected to the main control chip and is pulled up to 3.3V by a pull-up resistor (disposed on the main control chip side, not shown), the source is connected to the switching chip U100 and is pulled up to 1.8V (voltage set by VDDIO) by the resistor R118, and the gate is connected to 1.8V. Thereby realizing the level conversion from 3.3V of the main control chip to 1.8V of the switching chip.
In order to ensure the communication speed of the I2C interface (for example, to reach 100Kbps), in the present embodiment, the gates of the NMOS transistors Q100 and Q101 are directly connected to 1.8V, so as to increase the switching speed of the NMOS transistors.
In the present embodiment, the use of the level shift circuit has the following effects:
the bidirectional level conversion from 3.3V to 1.8V is realized, and the 3.3V of the main control chip cannot leak current to 1.8V (voltage set by VDDIO) or pull down a high-level signal of the main control chip through the bidirectional level conversion circuit, so that the reading and writing stability of the SIM card is influenced.
In this embodiment, the reset signal adopts a unidirectional level shift circuit, the reset output signal Dual _ SIM _ RST # of the main control chip is divided by resistors R123 and R125 and then input to the gate of the NMOS transistor Q102, the source of the NMOS transistor Q102 is grounded, and the drain is connected to the reset input interface RSTX (pin 2) of the switching chip U100. When the reset output signal Dual _ SIM _ RST # of the main control chip outputs a high level signal, the NMOS transistor Q102 is turned on, and outputs a low level signal to the reset input interface of the switching chip U100 to reset the switching chip U100.
In this embodiment, since both ends of the level shift circuit operate at low voltages, the level shift circuit operates at low voltagesNMOS transistors Q100, Q101 and Q102 need to be type-selected, and low V is selectedGSSuch as AP2318 GEN. V of AP2318GENGSOnly 0.4V, can satisfy the application of level conversion between 1.8V and 3.3V.
In this way, the utility model discloses a two SIM card switching circuits for gateway realizes the connection and the switching of wireless baseband chip and two independent SIM cassette, and matches through level conversion, guarantees the normal switching of SIM card and stabilizes the reading and writing to satisfy the application demand that the calamity was equipped with.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (5)
1. A double SIM card switching circuit for a gateway is characterized in that: comprises a first SIM card seat, a second SIM card seat, a switching chip and a level switching circuit,
the switching chip is used for connecting and switching an SIM interface of the wireless baseband chip with the first SIM card holder and the second SIM card holder, and the SIM interface of the wireless baseband chip works at a first voltage;
the level conversion circuit is used for interface level conversion of a switching chip and a main control chip, wherein the interface level of the switching chip is configured to be a first voltage, and the interface level of the main control chip is configured to be a second voltage;
the level conversion circuit comprises a unidirectional level conversion circuit unit and a plurality of bidirectional level conversion circuit units;
the bidirectional level conversion circuit unit comprises a first NMOS transistor, a first resistor and a second resistor; the source electrode of the first NMOS tube is connected with the switching chip and is pulled up to a first voltage through a first resistor; the drain electrode of the first NMOS is connected with the main control chip and is pulled up to a second voltage through a second resistor; the grid electrode of the first NMOS tube is connected with a first voltage;
the unidirectional level conversion circuit unit comprises a second NMOS tube, a third resistor, a fourth resistor and a fifth resistor, wherein the source electrode of the second NMOS tube is grounded, and the drain electrode of the second NMOS tube is connected with the switching chip and is pulled up to a first voltage through the third resistor; and the grid electrode of the second NMOS tube is connected with the main control chip through a fourth resistor and is grounded through a fifth resistor.
2. The dual SIM card switching circuitry for a gateway of claim 1, wherein: the model of the switching chip is TXS 02326A.
3. The dual SIM card switching circuitry for a gateway of claim 2, wherein: the first voltage is 1.8V, and the second voltage is 3.3V.
4. The dual SIM card switching circuitry for a gateway of claim 2, wherein: the number of the bidirectional level conversion circuit units is 2.
5. The dual SIM card switching circuitry for a gateway of claim 2, wherein: the model of the first NMOS tube and the model of the second NMOS tube are AP2318 GEN.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020559052.3U CN211457377U (en) | 2020-04-15 | 2020-04-15 | double-SIM card switching circuit for gateway |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020559052.3U CN211457377U (en) | 2020-04-15 | 2020-04-15 | double-SIM card switching circuit for gateway |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211457377U true CN211457377U (en) | 2020-09-08 |
Family
ID=72295649
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020559052.3U Active CN211457377U (en) | 2020-04-15 | 2020-04-15 | double-SIM card switching circuit for gateway |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN211457377U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112187303A (en) * | 2020-09-23 | 2021-01-05 | 深圳联想懂的通信有限公司 | SIM card expansion equipment, SIM card switching method and device |
| CN113490066A (en) * | 2021-07-05 | 2021-10-08 | 陕西中孚石油信息技术有限公司 | Data gateway equipment |
-
2020
- 2020-04-15 CN CN202020559052.3U patent/CN211457377U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112187303A (en) * | 2020-09-23 | 2021-01-05 | 深圳联想懂的通信有限公司 | SIM card expansion equipment, SIM card switching method and device |
| CN112187303B (en) * | 2020-09-23 | 2021-09-07 | 深圳联想懂的通信有限公司 | SIM card expansion equipment, SIM card switching method and device |
| CN113490066A (en) * | 2021-07-05 | 2021-10-08 | 陕西中孚石油信息技术有限公司 | Data gateway equipment |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN211457377U (en) | double-SIM card switching circuit for gateway | |
| US8200852B2 (en) | Multi-mode dongle for peripheral devices and associated methods | |
| CN101387944B (en) | Card type peripheral apparatus | |
| US8230151B2 (en) | Configurable data port for I2C or single-wire broadcast interface | |
| US11468822B2 (en) | Timing control board, drive device and display device | |
| CN105453372A (en) | Method and apparatus for fast battery charging with universal high power input source | |
| CN113704157B (en) | System for controlling multipath reset signals with different levels based on bus | |
| CN112715005A (en) | Transmitter circuit with N-type pull-up transistor and low voltage output swing | |
| TWI518515B (en) | Control chip and connection module utilizing the same | |
| CN214375036U (en) | Mobile device test system | |
| CN101336514B (en) | Communication circuit capable of signal voltage selection | |
| KR101139135B1 (en) | Configurable data port for I2C or single-wire broadcast interface | |
| US11121563B2 (en) | Power control circuit | |
| CN110262808B (en) | Burning device and burning equipment | |
| CN110120805B (en) | Logic functional block, logic circuit, integrated circuit and electronic device | |
| CN219980806U (en) | Signal level dynamic switching circuit for TF card and corresponding electronic equipment | |
| CN221039973U (en) | Master-slave switching control device, power-on control circuit and storage device system | |
| CN101353237B (en) | Micro-current sensing circuit and micro-current switch circuit | |
| CN215417541U (en) | On-chip EEPROM programming system | |
| CN221041793U (en) | Gating system of Type-C interface | |
| CN220711151U (en) | Charging circuit and docking station | |
| CN215300609U (en) | Level conversion circuit, mainboard and computer equipment | |
| CN217739749U (en) | Switch control circuit | |
| CN221304268U (en) | Storage device and processing system | |
| CN108962302B (en) | Storage device capable of realizing double-circuit power supply and reading and writing |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |