A SIM card reading circuit and a mobile terminal

Abstract

This utility model discloses a SIM card reading circuit and a mobile terminal, applied in the field of power electronics technology, to solve the problem of poor security in existing SIM card reading circuits. Specifically, it includes a digital isolator module establishing an electrically isolated bidirectional communication link between the control module and each SIM card connector; the control module transmits clock and data signals in isolation with each SIM card connector through the digital isolator module; it also generates independent power supply control signals to control the power supply to each SIM card connector; the power supply module independently supplies or de-energizes the corresponding SIM card connector according to the power supply control signals; and the SIM card connectors are physically connected to the SIM cards. In this way, by isolating and cutting off electrical hazards in the signal path, and by using independent power management to cut off electrical hazards in the power supply path, the security and reliability of the SIM card reading circuit are enhanced.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, and in particular to a SIM card reading circuit and a mobile terminal. Background Technology

[0002] With the development of the information industry, primarily driven by the Internet of Things (IoT), SIM cards (Subscriber Identity Modules) and similar chip cards are gradually taking on more functions in various products. Their main purpose is to serve as an important carrier for storing user authentication information in mobile terminals, facilitating reading and identification by other machines, and enabling control and reading / writing in conjunction with the IoT.

[0003] Currently, mobile terminals typically access and communicate with SIM card data through a built-in SIM card reader circuit. Because the SIM card connector in this circuit is exposed to the external environment, it is susceptible to external short circuits or electrostatic discharge (ESD). When an external short circuit or ESD occurs, these abnormal currents can directly act on the control module in the SIM card reader circuit through the SIM card connector, causing damage to the internal chip or malfunction, thus affecting the normal use of the entire mobile terminal. Furthermore, existing SIM card reader circuits generally lack effective protection mechanisms, making them highly vulnerable to damage from electrostatic interference and other similar situations, resulting in poor safety. Utility Model Content

[0004] This invention provides a SIM card reading circuit and a mobile terminal to solve the problem of poor security in existing SIM card reading circuits.

[0005] The technical solution provided by this utility model is as follows: On the one hand, this utility model provides a SIM card reading circuit, including: a control module, a power supply module, a digital isolator module, and at least one SIM card connector; The clock signal transmission end and data signal transmission end of the control module are respectively connected to the digital isolator module, and the control signal output end of the control module is connected to the control end of the power supply module; the clock signal transmission end and data signal transmission end of the SIM card connector are respectively connected to the digital isolator module; the power supply end of at least one SIM card connector is respectively connected to the output end of the power supply module. The digital isolator module is used to establish an electrically isolated bidirectional communication link between the control module and each SIM card connector; The control module is used to isolate and transmit clock and data signals with each SIM card connector through the digital isolator module; it is also used to generate power control signals that independently control the power supply to each SIM card connector. The power supply module is used to independently supply or de-energize the corresponding SIM card connector according to the power supply control signal; The SIM card connector is used for physical contact connection with the SIM card.

[0006] Optionally, when the SIM card reading circuit includes a SIM card connector, the digital isolator module includes: a first multi-channel isolator; The first end of the first channel of the first multi-channel isolator is connected to the clock signal transmission end of the control module, and the second end of the first channel of the first multi-channel isolator is connected to the clock signal transmission end of the SIM card connector; the first end of the second channel of the first multi-channel isolator is connected to the data signal transmission end of the control module, and the second end of the second channel of the first multi-channel isolator is connected to the data signal transmission end of the SIM card connector.

[0007] Optionally, when the SIM card reading circuit includes at least two SIM card connectors, the digital isolator module includes: a second multi-channel isolator and a distributor; The first terminal of the first channel of the second multi-channel isolator is connected to the clock signal transmission terminal of the control module, and the second terminal of the first channel of the second multi-channel isolator is connected to the first input terminal of the distributor; the first terminal of the second channel of the second multi-channel isolator is connected to the data signal transmission terminal of the control module, and the second terminal of the second channel of the second multi-channel isolator is connected to the second input terminal of the distributor. The distributor is connected to the clock signal transmission end and the data signal transmission end of each SIM card connector.

[0008] Optionally, when the SIM card reading circuit includes at least two SIM card connectors, the digital isolator module includes: a multiplexing isolator; The on / off selection terminal of the multiplexer isolator is connected to the control module. The clock signal transmission terminal on the first side of the multiplexer isolator is connected to the clock signal transmission terminal of the control module, and the data signal transmission terminal on the first side of the multiplexer isolator is connected to the data signal transmission terminal of the control module. Each clock signal transmission terminal on the second side of the multiplexer isolator is connected to the clock signal transmission terminal of each SIM card connector, and each data signal transmission terminal on the second side of the multiplexer isolator is connected to the data signal transmission terminal of each SIM card connector.

[0009] Optionally, the power supply module includes: a power supply and at least one controllable switch; The output terminal of the power supply is connected to the power supply terminal of all SIM card connectors in the circuit. A controllable switch is connected in series on the power supply line between the output terminal of the power supply and the power supply terminal of each SIM card connector. The control signal output terminal of the control module is connected to the control terminal of each controllable switch.

[0010] Optionally, the power supply module may also include: a voltage conversion circuit; The input terminal of the voltage conversion circuit is connected to the power supply, the output terminal of the voltage conversion circuit is connected to the input terminal of the corresponding controllable switch, and the control terminal of the voltage conversion circuit is connected to the control module. The voltage conversion circuit is used to convert the output voltage of the power supply to the power supply voltage of the SIM card connector.

[0011] Optionally, the SIM card reading circuit may further include: at least one power supply voltage detection circuit; The input terminal of the power supply voltage detection circuit is connected between the corresponding controllable switch and the SIM card connector, and the output terminal of the power supply voltage detection circuit is connected to the control module. The power supply voltage detection circuit is used to detect the power supply voltage of the corresponding SIM card connector.

[0012] Optionally, the power supply voltage detection circuit includes: a first resistor and a second resistor; The first end of the first resistor is connected to the output end of the controllable switch, the second end of the first resistor is connected to ground via the second resistor, and the second end of the first resistor is also connected to the control module.

[0013] Optionally, the SIM card reading circuit may also include: a power supply voltage detection circuit; The input terminal of the power supply voltage detection circuit is connected to the output terminal of the power supply, and the output terminal of the power supply voltage detection circuit is connected to the control module. The power supply voltage detection circuit is used to detect the output voltage of the power supply.

[0014] On the other hand, this utility model provides a mobile terminal, including the aforementioned SIM card reading circuit.

[0015] The beneficial effects of this utility model are as follows: This invention introduces a digital isolator module and an independently controllable power supply module. The digital isolator establishes an electrically isolated bidirectional communication link between the control module and the SIM card connector, blocking abnormal voltage / current introduced by external static electricity or short circuits from reaching the internal core components through the signal lines. Simultaneously, the power supply module provides independently switchable power to each SIM card connector based on the independent power supply control signal generated by the control module. This ensures that when a connector experiences an external short circuit, its power supply can be quickly cut off without affecting other parts or the internal core components of the SIM card reading circuit, effectively electrically isolating the internal control module from the externally vulnerable SIM card interface. By isolating and cutting off electrical hazards in the signal path and by using independent power management to cut off electrical hazards in the power supply path, the invention significantly improves the resistance of the internal core components of the SIM card reading circuit to external short circuits and electrostatic discharge, enhancing the safety and reliability of the SIM card reading circuit.

[0016] Other features and advantages of this invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the present invention and constitute a part of this invention, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the first structure of the SIM card reading circuit in this embodiment of the present invention; Figure 2 This is a schematic diagram of a second structure of the SIM card reading circuit in an embodiment of this utility model; Figure 3 This is a schematic diagram of the third structure of the SIM card reading circuit in this embodiment of the present invention; Figure 4 This is a schematic diagram of the fourth structure of the SIM card reading circuit in this embodiment of the present invention; Figure 5 This is a schematic diagram of the fifth structure of the SIM card reading circuit in this embodiment of the present invention; Figure 6 This is a schematic diagram of the sixth structure of the SIM card reading circuit in this embodiment of the present invention; Figure 7 This is a schematic diagram of the seventh structure of the SIM card reading circuit in this embodiment of the present invention; Figure 8This is a schematic diagram of the eighth structure of the SIM card reading circuit in this embodiment of the present invention.

[0018] Icons: 100 - SIM card reader circuit; 110 - Control module; 120 - Power supply module; 121 - Power supply; 122 - Controllable switch; 123 - Voltage conversion circuit; 130 - Digital isolator module; 131 - First multi-channel isolator; 132 - Second multi-channel isolator; 133 - Distributor; 134 - Multiplexer isolator; 140 - SIM card connector; 150 - Power supply voltage detection circuit; 160 - Power supply voltage detection circuit; R1 - First resistor; R2 - Second resistor. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] This utility model embodiment provides a SIM card reading circuit, see reference. Figure 1 As shown, the SIM card reading circuit 100 includes at least: a control module 110, a power supply module 120, a digital isolator module 130, and at least one SIM card connector 140; The clock signal transmission terminal and data signal transmission terminal of the control module 110 are respectively connected to the digital isolator module 130, and the control signal output terminal of the control module 110 is connected to the control terminal of the power supply module 120; the clock signal transmission terminal and data signal transmission terminal of the SIM card connector 140 are respectively connected to the digital isolator module 130; at least one power supply terminal of the SIM card connector 140 is respectively connected to the output terminal of the power supply module 120. The digital isolator module 130 is used to establish an electrically isolated bidirectional communication link between the control module 110 and each SIM card connector 140; The control module 110 is used to isolate and transmit clock signals and data signals with each SIM card connector 140 through the digital isolator module 130; it is also used to generate power control signals that independently control the power supply on and off of each SIM card connector 140. The power supply module 120 is used to independently supply power or de-energize the corresponding SIM card connector 140 according to the power supply control signal; The SIM card connector 140 is used for physical contact connection with the SIM card.

[0021] exist Figure 1In the SIM card reading circuit 100 shown, the digital isolator module 130 establishes electrical isolation between the control module 110 and the SIM card connector 140, preventing surge or ground interference and isolating against ESD and other electrical shocks. The digital isolator module 130 also establishes an electrically isolated bidirectional communication link between the control module 110 and each SIM card connector 140, accommodating multiple signal transmissions and ensuring signal integrity. The digital isolator module 130 may include a bidirectional digital isolator chip. The SIM card connector 140 provides a physical interface, contacting the metal contacts of the SIM card to transmit clock signals, data signals, power signals, and ground signals. The power supply module 120 provides an adjustable power supply voltage and an independent power supply line for each SIM card connector 140. When the control module 110 needs to read a SIM card, the power supply module 120 connects the corresponding power supply line to power the corresponding SIM card connector 140. The control module 110 includes a microcontroller (MCU) or a dedicated communication chip. The control signal output terminal of the control module 110 is a GPIO interface, and the clock signal transmission terminal and data signal transmission terminal of the control module 110 are communication interfaces. After receiving an external input command to read a specific SIM card, the control module 110 outputs a power supply control signal to the power supply module 120 through its control signal output terminal to control the power supply module 120 to connect the independent power supply to the corresponding SIM card connector 140. The control module 110 can send clock signals and data signals to the digital isolator through its clock signal transmission terminal and data signal transmission terminal, respectively, and simultaneously receive the response signal from the SIM card connector 140 fed back to the data signal transmission terminal by the digital isolator.

[0022] In practical applications, during the initialization phase, the control module 110 detects the insertion status of all SIM card connectors 140. By default, the control module 110 disables power to all SIM card connectors 140, meaning all power supply lines of the power supply module 120 are disconnected. When a SIM card is being read, the control module 110 sends a power control signal to the power supply module 120 to enable power to the corresponding SIM card connector 140. The power supply module 120 then enables power to the corresponding SIM card connector 140. The control module 110 then sends clock and data signals to the corresponding SIM card connector 140 via the digital isolator module 130 to establish communication with the corresponding SIM card. The corresponding SIM card response data is transmitted back to the control module 110 via the digital isolator.

[0023] Thus, by introducing a digital isolator module 130 and an independently controllable power supply module 120, this invention establishes an electrically isolated bidirectional communication link between the control module 110 and the SIM card connector 140, blocking abnormal voltage / current introduced by external static electricity or short circuits from being transmitted to the internal core components through the signal lines. Simultaneously, the power supply module 120 provides independently switchable power to each SIM card connector 140 based on the independent power supply control signal generated by the control module 110, ensuring that when a connector experiences an external short circuit, its power supply can be quickly cut off without affecting other parts or the internal core components of the SIM card reading circuit 100. This achieves electrical separation between the internal control module and the externally vulnerable SIM card interface. By isolating and cutting off electrical hazards on the signal path, and by using independent power management to cut off electrical hazards on the power path, the internal core components of the SIM card reading circuit 100 are significantly improved in terms of resistance to external short circuits and electrostatic discharge, enhancing the safety and reliability of the SIM card reading circuit 100.

[0024] In practical implementation, when the SIM card reading circuit includes a SIM card connector, the digital isolator module can have various structures to achieve its function; see [reference needed]. Figure 2 As shown, the digital isolator module 130 includes: a first multi-channel isolator 131; The first end of the first channel of the first multi-channel isolator 131 is connected to the clock signal transmission end of the control module 110, and the second end of the first channel of the first multi-channel isolator 131 is connected to the clock signal transmission end of the SIM card connector 140; the first end of the second channel of the first multi-channel isolator 131 is connected to the data signal transmission end of the control module 110, and the second end of the second channel of the first multi-channel isolator 131 is connected to the data signal transmission end of the SIM card connector 140.

[0025] exist Figure 2 In the SIM card reading circuit 100 shown, the first multi-channel isolator 131 includes at least two channels. The first channel is a bidirectional clock isolation channel used to isolate the transmission of clock signals, and the second channel is a bidirectional data isolation channel used to isolate the transmission of data signals. The forward signal isolation transmission from the control module 110 to the SIM card includes the control module 110 sending commands through the clock signal transmission terminal and the data signal transmission terminal. After isolation by the first multi-channel isolator 131, the signals are transmitted to the SIM card connector 140 in an electrically isolated manner. The reverse signal isolation transmission from the SIM card to the control module 110 includes the SIM card response data (such as status words and data blocks) returning through the data signal transmission terminal. The first multi-channel isolator 131 reverse-isolates the signals and transmits them to the control module 110, ensuring reliable bidirectional communication.

[0026] In practical implementation, when the SIM card reading circuit includes at least two SIM card connectors, the digital isolator module can have various structures to achieve its function; see [reference needed]. Figure 3 As shown, the digital isolator module 130 may include: a second multi-channel isolator 132 and a distributor 133; The first end of the first channel of the second multi-channel isolator 132 is connected to the clock signal transmission end of the control module 110, and the second end of the first channel of the second multi-channel isolator 132 is connected to the first input end of the distributor 133; the first end of the second channel of the second multi-channel isolator 132 is connected to the data signal transmission end of the control module 110, and the second end of the second channel of the second multi-channel isolator 132 is connected to the second input end of the distributor 133. The distributor 133 is connected to the clock signal transmission end and the data signal transmission end of each SIM card connector 140, respectively.

[0027] exist Figure 3 In the SIM card reading circuit 100 shown, the second multi-channel isolator 132 includes at least two channels. The first channel is a bidirectional clock isolation channel used to isolate the transmission of clock signals, and the second channel is a bidirectional data isolation channel used to isolate the transmission of data signals. The distributor 133 is used to transmit the isolated clock and data signals to all SIM card connectors 140 in the SIM card reading circuit 100. However, since other SIM cards are in a high-impedance state due to power failure, only the SIM card connectors 140 that are powered on will respond, and the SIM card response data will be fed back to the control module 110 through the distributor 133 and the second channel of the second multi-channel isolator 132.

[0028] In practical implementation, when the SIM card reading circuit includes at least two SIM card connectors, the digital isolator module can have various structures to achieve its function; see [reference needed]. Figure 4 As shown, the digital isolator module 130 may include: a multiplexing isolator 134; The on / off selection terminal of the multiplexing isolator 134 is connected to the control module 110. The clock signal transmission terminal on the first side of the multiplexing isolator 134 is connected to the clock signal transmission terminal of the control module 110, and the data signal transmission terminal on the first side of the multiplexing isolator 134 is connected to the data signal transmission terminal of the control module 110. Each clock signal transmission terminal on the second side of the multiplexing isolator 134 is connected to the clock signal transmission terminal of each SIM card connector 140, and each data signal transmission terminal on the second side of the multiplexing isolator 134 is connected to the data signal transmission terminal of each SIM card connector 140.

[0029] exist Figure 4In the SIM card reading circuit 100 shown, the multiplexing isolator 134 integrates the functions of a multiplexer and a digital isolator, supporting multi-channel selection and electrically isolated data transmission. The control module 110 selects the target SIM card channel by sending a SEL signal to the on / off selection terminal of the multiplexing isolator (e.g., SEL=01 selects the first SIM card). The multiplexing isolator 134 internally activates the selected channel, transmitting clock and data signals from the first side to the corresponding channel on the second side. The control module 110 can switch the SEL signal as needed according to actual reading requirements to achieve communication with the corresponding SIM card. Only when reading a specific SIM card does the power supply module 120 connect the power supply line to the SIM card connector 140 where that SIM card is located; channels of unselected SIM cards are in a high-impedance state to avoid signal interference. Furthermore, the power supply timing of the power supply module 120 must be synchronized with the channel selection to ensure that communication is established only after the SIM card connector 140 is powered on.

[0030] In practical implementation, the power supply module in the SIM card reading circuit has various structures to achieve its function; see [reference needed]. Figure 5 As shown, the power supply module 120 includes: a power supply 121 and at least one controllable switch 122; The output terminal of the power supply 121 is connected to the power supply terminal of all SIM card connectors 140 in the circuit. A controllable switch 122 is connected in series on the power supply line between the output terminal of the power supply 121 and the power supply terminal of each SIM card connector 140. The control signal output terminal of the control module 110 is connected to the control terminal of each controllable switch 122.

[0031] exist Figure 5 In the SIM card reading circuit 100 shown, the power supply 121 provides the required power supply voltage to the SIM card connector 140. A controllable switch 122 is connected in series on the power supply line between each SIM card connector 140 and the power supply 121. The controllable switch 122, under the control of the control module 110, connects the corresponding power supply line when the control module 110 needs to communicate with a designated SIM card, so that the power supply 121 supplies power to the designated SIM card connector 140. This reduces static power consumption by supplying power to the SIM card connector 140 only when the control module 110 is communicating with the designated SIM card. By independently cutting off the power to unused SIM card connectors 140, the power supply to unused SIM card connectors 140 is isolated from the SIM card reading circuit 100, avoiding signal crosstalk and potential short-circuit risks. Specifically, the controllable switch 122 can be one of a logic gate chip, a switching chip, a transistor circuit, a MOSFET circuit, or a high / low-side drive circuit. The type of controllable switch 122 can be selected according to the product design requirements.

[0032] In one possible implementation, see [reference] Figure 6 As shown, the power supply module 120 also includes a voltage conversion circuit 123; The input terminal of the voltage conversion circuit 123 is connected to the power supply 121, the output terminal of the voltage conversion circuit 123 is connected to the input terminal of the corresponding controllable switch 122, and the control terminal of the voltage conversion circuit 123 is connected to the control module 110. The voltage conversion circuit 123 is used to convert the output voltage of the power supply 121 into the power supply voltage of the SIM card connector 140.

[0033] exist Figure 6 In the SIM card reading circuit 100 shown, when the output voltage of the power supply 121 does not match the power supply voltage required by the SIM card connector 140, the voltage conversion circuit 123 can convert the output voltage of the power supply 121 into the power supply voltage of the SIM card connector 140 through boost or buck conversion, thereby ensuring a safe power supply to the SIM card connector 140. Specifically, the voltage conversion circuit 123 can use an LDO (low dropout linear regulator) or a DC-DC converter to convert the output voltage of the power supply 121 into the power supply voltage of the SIM card connector 140. The power supply voltage of the SIM card connector 140 is typically 3.3V.

[0034] In one possible implementation, see [reference] Figure 7 As shown, the SIM card reading circuit 100 also includes at least one power supply voltage detection circuit 150; The input terminal of the power supply voltage detection circuit 150 is connected between the corresponding controllable switch 122 and the SIM card connector 140, and the output terminal of the power supply voltage detection circuit 150 is connected to the control module 110. The power supply voltage detection circuit 150 is used to detect the power supply voltage of the corresponding SIM card connector 140.

[0035] exist Figure 7In the SIM card reading circuit 100 shown, each controllable switch 122 is connected to a power supply voltage detection circuit 150 between its power supply terminal and the SIM card connector 140. The power supply voltage detection circuit 150 detects the power supply voltage of the corresponding SIM card connector 140 in real time and obtains the power supply detection voltage corresponding to the power supply voltage of the SIM card connector 140. The power supply detection voltage is transmitted to the first ADC pin of the control module 110 in real time so that the control module 110 performs analog-to-digital conversion on the power supply detection voltage and determines the power supply status of the SIM card connector 140 based on the analog-to-digital conversion power supply detection voltage. After the control power supply module 120 supplies power to the designated SIM card connector 140, the control module 110 receives the power supply detection detected by the power supply voltage detection circuit 150 corresponding to the SIM card connector 140. If the power supply detection voltage after analog-to-digital conversion is less than the preset power supply voltage threshold, it is determined that there is a fault in the power supply line of the SIM card connector 140 or that the SIM card connector 140 has an external short circuit. The control module 110 can report the fault to the external device and execute corresponding protection measures. The power supply voltage threshold is the minimum value of the power supply detection voltage when the SIM card connector 140 is normally supplied with power.

[0036] For details, please refer to Figure 7 As shown, the power supply voltage detection circuit 150 includes: a first resistor R1 and a second resistor R2; The first end of the first resistor R1 is connected to the output end of the controllable switch 122, the second end of the first resistor R1 is connected to ground via the second resistor R2, and the second end of the first resistor R1 is also connected to the control module 110.

[0037] exist Figure 7 In the SIM card reading circuit 100 shown, the first resistor R1 and the second resistor R2 connected in series form a voltage divider branch, which reduces the power supply voltage of the SIM card connector 140 to the power supply detection voltage according to a preset ratio. The preset ratio is determined based on the resistance values ​​of the first resistor R1 and the second resistor R2.

[0038] In one possible implementation, see [reference] Figure 8 As shown, the SIM card reading circuit 100 also includes a power supply voltage detection circuit 160; The input terminal of the power supply voltage detection circuit 160 is connected to the output terminal of the power supply 121, and the output terminal of the power supply voltage detection circuit 160 is connected to the control module 110. The power supply voltage detection circuit 160 is used to detect the output voltage of the power supply 121.

[0039] exist Figure 8In the SIM card reading circuit 100 shown, the output terminal of the power supply 121 is connected to a power supply voltage detection circuit 160. The power supply voltage detection circuit 160 detects the output voltage of the power supply 121 in real time and obtains a power supply detection voltage corresponding to the output voltage of the power supply 121. The power supply detection voltage is transmitted in real time to the second ADC pin of the control module 110 so that the control module 110 performs analog-to-digital conversion on the power supply detection voltage. The control module 110 compares the converted power supply detection voltage with the standard power supply voltage value. If the difference between the converted power supply detection voltage and the preset standard power supply voltage value is greater than a preset deviation threshold, the power supply 121 is determined to be faulty. The control module 110 can report the fault to an external device and execute corresponding protection measures. The standard power supply voltage value is the power supply detection voltage corresponding to the rated output voltage of the power supply 121, and the deviation threshold is the maximum deviation between the power supply detection voltage and the preset standard power supply voltage value when the power supply 121 is operating normally. Specifically, the power supply voltage detection circuit 160 and the power supply voltage detection circuit 150 have the same structure, but different resistor values.

[0040] Based on the same concept, this utility model embodiment also provides a mobile terminal, which includes at least the above-mentioned SIM card reading circuit.

[0041] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0042] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this utility model without departing from the spirit and scope of the embodiments of this utility model. Therefore, if these modifications and variations to the embodiments of this utility model fall within the scope of the claims of this utility model and their equivalents, then this utility model also intends to include these modifications and variations.

Claims

1. A SIM card reading circuit, characterized by comprising: include: The system includes a control module, a power supply module, a digital isolator module, and at least one SIM card connector. The clock signal transmission terminal and data signal transmission terminal of the control module are respectively connected to the digital isolator module, and the control signal output terminal of the control module is connected to the control terminal of the power supply module. The clock signal transmission end and data signal transmission end of the SIM card connector are respectively connected to the digital isolator module; At least one SIM card connector's power supply terminal is connected to the output terminal of the power supply module; The digital isolator module is used to establish an electrically isolated bidirectional communication link between the control module and each of the SIM card connectors; The control module is used to isolate and transmit clock signals and data signals with each of the SIM card connectors through the digital isolator module; it is also used to generate power supply control signals that independently control the power supply on and off of each of the SIM card connectors. The power supply module is used to independently supply power or de-energize the corresponding SIM card connector according to the power supply control signal; The SIM card connector is used for physical contact connection with the SIM card; The power supply module includes: a power supply and at least one controllable switch; The output terminal of the power supply is connected to the power supply terminal of all SIM card connectors in the circuit. A controllable switch is connected in series on the power supply line between the output terminal of the power supply and the power supply terminal of each SIM card connector. The control signal output terminal of the control module is connected to the control terminal of each controllable switch. The SIM card reading circuit also includes: at least one power supply voltage detection circuit; The input terminal of the power supply voltage detection circuit is connected between the corresponding controllable switch and the SIM card connector, and the output terminal of the power supply voltage detection circuit is connected to the control module. The power supply voltage detection circuit is used to detect the power supply voltage of the corresponding SIM card connector.

2. The SIM card reading circuit according to claim 1, characterized in that, When the SIM card reading circuit includes a SIM card connector, the digital isolator module includes: a first multi-channel isolator; The first end of the first channel of the first multi-channel isolator is connected to the clock signal transmission end of the control module, and the second end of the first channel of the first multi-channel isolator is connected to the clock signal transmission end of the SIM card connector; the first end of the second channel of the first multi-channel isolator is connected to the data signal transmission end of the control module, and the second end of the second channel of the first multi-channel isolator is connected to the data signal transmission end of the SIM card connector.

3. The SIM card reading circuit according to claim 1, characterized in that, When the SIM card reading circuit includes at least two SIM card connectors, the digital isolator module includes: a second multi-channel isolator and a distributor; The first end of the first channel of the second multi-channel isolator is connected to the clock signal transmission terminal of the control module, and the second end of the first channel of the second multi-channel isolator is connected to the first input terminal of the distributor; the first end of the second channel of the second multi-channel isolator is connected to the data signal transmission terminal of the control module, and the second end of the second channel of the second multi-channel isolator is connected to the second input terminal of the distributor. The distributor is connected to the clock signal transmission end and the data signal transmission end of each SIM card connector.

4. The SIM card reading circuit according to claim 1, characterized in that, When the SIM card reading circuit includes at least two SIM card connectors, the digital isolator module includes: a multiplexing isolator; The on / off selection terminal of the multiplexing isolator is connected to the control module. The clock signal transmission terminal on the first side of the multiplexing isolator is connected to the clock signal transmission terminal of the control module, and the data signal transmission terminal on the first side of the multiplexing isolator is connected to the data signal transmission terminal of the control module. Each clock signal transmission terminal on the second side of the multiplexing isolator is connected to the clock signal transmission terminal of each SIM card connector, and each data signal transmission terminal on the second side of the multiplexing isolator is connected to the data signal transmission terminal of each SIM card connector.

5. The SIM card reading circuit according to claim 1, characterized in that, The power supply module also includes: a voltage conversion circuit; The input terminal of the voltage conversion circuit is connected to the power supply, the output terminal of the voltage conversion circuit is connected to the input terminal of the corresponding controllable switch, and the control terminal of the voltage conversion circuit is connected to the control module. The voltage conversion circuit is used to convert the output voltage of the power supply into the power supply voltage of the SIM card connector.

6. The SIM card reading circuit according to claim 1, characterized in that, The power supply voltage detection circuit includes: a first resistor and a second resistor; The first end of the first resistor is connected to the output end of the controllable switch, the second end of the first resistor is connected to ground via the second resistor, and the second end of the first resistor is also connected to the control module.

7. The SIM card reading circuit according to claim 1, characterized in that, Also includes: Power supply voltage detection circuit; The input terminal of the power supply voltage detection circuit is connected to the output terminal of the power supply, and the output terminal of the power supply voltage detection circuit is connected to the control module. The power supply voltage detection circuit is used to detect the output voltage of the power supply.

8. A mobile terminal, characterized by include: The SIM card reading circuit as described in any one of claims 1-7.

Images