Signal power management circuits and smart cards including the same are provided. For example, a signal power management circuit comprises a rectifier that is configured to rectify a received radio frequency signal and output a first rectified voltage, a first regulator that is configured to maintain the first rectified voltage at a predetermined first voltage level, and a second regulator that is configured to receive an output of the first regulator and maintain a second rectified voltage different from the first rectified voltage at a predetermined second voltage level. A signal detector of the signal power management circuit is configured to receive the first rectified voltage and the second rectified voltage and detect a signal component of the received radio frequency signal on the basis of a difference between the first voltage level of the first rectified voltage and the second voltage level of the second rectified voltage.

A smart card with improved power stability is provided. The smart card comprises a rectification signal line through which a rectification signal extracted from a radio frequency (RF) signal is provided; a regulator configured to regulate a voltage of the rectification signal line to a first voltage; a power circuit configured to extract a power component from the rectification signal using an output of the regulator; a logic circuit configured to receive the power component and generate a reception enable signal on the basis of the power component; a demodulator which is enabled by the reception enable signal provided from the logic circuit and configured to extract a signal component from the rectification signal; a capacitor controller which is enabled by the reception enable signal provided from the logic circuit and configured to generate a capacitor enable signal; and a capacitor circuit which is connected to the rectification signal line and has capacitance changed according to the capacitor enable signal.

In accordance with an embodiment, a linear voltage regulator includes: a first transistor coupled between a first input terminal and an output terminal, the first input terminal adapted to receive a first voltage, and the output terminal adapted to provide a regulated voltage; a second transistor coupled between a second input terminal and the output terminal, the second input terminal adapted to receive a second voltage; and an amplifier of a difference between a third voltage proportional to the voltage at the output terminal and a reference voltage, an output of said amplifier being selectively coupled to a control terminal of the first transistor and to a control terminal of the second transistor, the amplifier being supplied by a fourth voltage corresponding to a highest voltage of the first voltage and the second voltage.

A mobile payment device includes a central control unit, an identity authentication module, an input interface, a display module, a security chip, an induction antenna and a cuboid casing. The central control unit is electrically connected to the identity authentication module, the input interface, the display module, and the security chip. The central control unit selects, according to an input signal inputted by a holder of the mobile payment device, one of at least one card information displayed on the display module to allow the selected card information to serve as payment card information and starts the security chip according to a signal inputted by the holder before making payment, thereby allowing the security chip to provide the payment card information to the induction antenna.

Low power non-volatile non-charge-based variable supply RFID tag memory devices and methods for reading and writing predetermined ID values for a RFID tag are described. The RFID tag memory device includes a reference/bias generator that receives and provides voltages and currents for write and read operations, a clocked comparator that provides a voltage comparison with a reference voltage, a shift register that receives a non-charge-based memory component value saved in the shift register, a memory cell that includes non-charge-based memory components to store corresponding predetermined ID values, a ring counter that provides ring signals to enable sequential writing and reading of the predetermined ID values to and from the memory cell, a write decision component that receives ring signals to enable the write operation, an output select/isolation component for reading and a read/write component to enable reading or writing the predetermined ID values in response to received ring signals.

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.

Various aspects of the disclosure generally relate to security for a credit card processing reader. Part of security for a reader is a secure cover having a trace mesh to discourage drilling through the cover. The mesh may be connected to one or more landing areas on the cover. The landing area has electrical pads with trace routing that provides tamper protection for the landing area.

A smart card with a fingerprint sensing system, includes a controller and a fingerprint sensing device. When the fingerprint sensing device senses a fingerprint to generate a fingerprint frame data, the controller enters a sleep mode, and when the controller reads the fingerprint frame data, the fingerprint sensing device stops sensing the fingerprint. Since operations of sensing the fingerprint and reading the fingerprint frame data do not occur at the same time, the high current condition can be avoided so as to decrease power consumption.

A dual frequency HF-UHF RFID integrated circuit including a power supply. The power supply includes: an HF branch including an HF rectifier and a linear voltage regulator, wherein the HF rectifier is configured to be connected to a resonance circuit formed by a HF antenna-coil and a resonance capacitor and wherein the HF rectifier is connected to the linear voltage regulator; a UHF branch including a UHF rectifier and a shunt voltage regulator, wherein the UHF rectifier has a charge pump and is configured to be connected to a UHF antenna and wherein the UHF rectifier is connected to the shunt voltage regulator; and a supply line, wherein the linear voltage regulator and the shunt voltage regulator are both connected to the supply line of the power supply.

A first element and a second element of a same device communicate with each other. The first element sends the second element a first piece of information representative of energy supplied by an electromagnetic field supplying power the device. The second element adapts its operating frequency as a function of the first piece of information.