Maxim Integrated Products, Inc.

Chen-Hsien Hung

Shiau Chwun George Pwu

Matthew Ray Harrington

Tao Huang

A start-up control for a transmitter (TX) output driver is implemented to prevent the stick state problem when the TX driver is not toggling. TX output driver is set in a high impedance (HZ) mode when data zero is delivered from the digital base band (DBB) and set in an enhanced mode to deliver a stronger signal when data one is delivered from the DBB. The transmitter comprises a dual-loop PLL to synchronize the TX output pulse and the carrier. The dual-loop PLL is composed of a relaxation oscillator, a 1Loop, and a 2Loop. The 1loop is a voltage-controlled oscillator comprising the relaxation oscillator and an operational transconductance amplifier. The 2loop is a loop comprising a phase frequency detector, a charge pump, a loop filter and the VCO of the 1loop.

Advanced synchronization schemes for NFC card emulation mode, peer-to-peer mode and RFID tag design

A power switch control circuit is provided for power management in one-wire application. The circuit comprises a controllable switch coupled between an input node and an internal power node. A comparator is utilized for power loss sensing to close the switch when necessary to minimize the power loss while the input is low or floating. A watchdog circuit is incorporated within the control circuit to pull down the input node periodically to detect small leakage current when the input node is floating.

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Dallas, TX, United States of America

Chen-Hsien Hung