An integrated circuit (IC) includes a wireless power receive circuit, a wireless communication module, and a circuit module. The wireless power receive circuit generates a supply voltage from a wireless power electromagnetic signal. The wireless communication module converts inter-chip outbound data into an inter-chip outbound wireless signal; transmits the inter-chip outbound wireless signal to another IC; receives an inter-chip inbound wireless signal from the other IC; and converts the inter-chip inbound wireless signal into inter-chip inbound data. The circuit module is powered by the supply voltage and is operable to generate the inter-chip outbound data; and process the inter-chip inbound data.

There are provided systems and methods for a physical card having one or more location detection modules A physical payment card may include one or more components to limit card reading of card data stored to the card using a location detection chip. The location detection chip may receive power from a source when inserted to a card reader, and may then determine a location of the card, such as a coordinate location of the card or nearby detected device. The location detection chip may determine if this location or device matches authorized locations stored in a memory of the card. If it does, power may be provided to a card chip of the card. The card chip of the card reads card data from a memory of the card and may then output the card data to the card reader.

A retrofitted credit card including a certified smart card chip, a display and retrofitted emulation circuitry operative to enable the certified smart card chip to communicate information to the display notwithstanding that the certified smart card chip is configured for communication only with an external read/write device.

In the present invention, by connecting a band-gap reference voltage module unit to a threshold unit of a limiter circuit, the ON-voltage of the threshold unit can be dynamically and continuously controlled; and the output voltage value of the band-gap reference voltage module unit can be arbitrarily set as needed for operating the circuit. When a voltage of the antenna terminal is higher than the sum of this band-gap reference voltage value and the respective threshold voltage of the serial MOS transistors, the threshold unit is turned ON to switch on a grounded path, so that charge at the antenna is output to the ground; in this way, the amount of charge at the antenna terminal is reduced and the rectified DC voltage is thus reduced. When the voltage at the antenna terminal is lower than the sum of this band-gap reference voltage value and the respective threshold voltage of the serial MOS transistors, the threshold unit is turned off to switch off the grounded path. The rectifier circuit rectifies all the charges at the antenna end into DC power for powering the load circuit. In this way, the function of continuously adjust the limited voltage is achieved, so that the limited voltage value has continuity and accuracy, and the stability of the operating voltage value of the circuits is guaranteed.

When an IC card is passed over an external card reading and writing apparatus, the IC card starts communication with the card reading and writing apparatus via a wireless interface, so that a change in the internal state of the IC card is reported to an external device via an external wired interface or a dedicated control signal line, thus allowing a specific application to be enabled on the external device or allowing a controller to be powered on and activated. Alternatively, the controller is powered off and deactivated. Accordingly, processing according to the communication state between the IC card and the card reading and writing apparatus or the internal state of the IC card can be smoothly initiated.

A multimedia card includes a substrate, and a main control chip, a memory chip, and an interface contacts that are disposed on the substrate. The main control chip and the memory chip are covered with a packaging layer. The interface contacts includes a power contact, configured to receive a first voltage that is input from the outside; and a transformer circuit is further disposed on the substrate, is coupled to the interface contacts, the main control chip, and the memory chip, and is configured to convert the input first voltage into a second voltage, to provide two types of power supplies with the first voltage and the second voltage for the main control chip and the memory chip. In the foregoing manner, an area of the multimedia card is reduced, and a quantity of working modes of the multimedia card increases.

According to a first aspect of the present disclosure, a power switching circuit is provided, comprising: a bandgap reference circuit configured to receive an input voltage and to generate a reference voltage in response to receiving said input voltage; a supply selection circuit configured to receive at least two supply voltages, to select the highest voltage of said supply voltages and to provide said highest voltage to the bandgap reference circuit. According to a second aspect of the present disclosure, a corresponding method of operating a power switching circuit is conceived.

This disclosure is generally directed to an RFID system that includes a hybrid RFID tag offering a functionality of a passive RFID tag and an active RFID tag. When operating as a passive RFID tag, an RF signal received from an RFID reader is harvested to produce a DC voltage for powering the hybrid RFID tag. The harvested DC voltage is coupled into a capacitor at a slow-charging rate so as to avoid a capacitor inrush current causing an abrupt power supply voltage drop. A controller chip in the hybrid RFID tag can execute some RFID functions at this time, thereby speeding up a response to the RFID reader. The capacitor is then charged at a fast-charging rate for storing a reserve charge. The hybrid RFID tag can subsequently use the reserve charge to operate as an active RFID tag without waiting for an RF signal from the RFID reader.

To prevent damage on an element even when a voltage high enough to break the element is input. A semiconductor device of the invention operates with a first voltage and includes a protection circuit which changes the value of the first voltage when the absolute value of the first voltage is higher than a reference value. The protection circuit includes: a control signal generation circuit generating a second voltage based on the first voltage and outputting the generated second voltage; and a voltage control circuit. The voltage control circuit includes a transistor which has a source, a drain, and a gate, and which is turned on or off depending on the second voltage input to the gate and thus controls whether the value of the first voltage is changed based on the amount of current flowing between the source and the drain. The transistor also includes an oxide semiconductor layer.

An actively transmitting tag detects a shift of a phase of an antenna signal (as) with regard to a phase of a transmitted signal (ts) in time intervals with a length of one half-period of a subcarrier, in which time intervals it transmits high-frequency wave packets with their phase being inverted according to a communication protocol at the ends of said half-periods. Generation of said wave packets is controlled by said phase shift in a way that said phase shift retains its absolute value at transitions into subsequent half-periods. Synchronizing the tag's transmission to a received interrogator signal carried out even during tag's transmitting enables the tag to transmit according to protocol ISO 14443 B by inverting a phase at transitions between said half-periods. Said synchronizing is carried out although no time window without a tag transmitting exists within the transmitted data frame.