Sk Keyfoundry Inc.

Wanchul Kong

Keesik Ahn

Jungho Kim

A bidirectional I/O circuit includes an output post driver configured to control an output signal of a bidirectional pad during a normal mode, a floating N-well network configured to apply a VDD-level bias to the output post driver based on an input signal of the bidirectional pad during a power down mode, and a post driver control circuit configured to set an input voltage level of the output post driver to a VDD level during the power down mode to prevent a leakage current path from being formed through the output post driver. A parasitic diode is formed between the drain of the first PMOS transistor and an N-well of the first PMOS transistor. The N-well of the first PMOS transistor is connected to the floating N-well network, and the source and the N-well of the first PMOS transistor are not physically connected to each other.

Bidirectional I/O circuit and integrated circuit including bidirectional I/O circuit

A retention flip-flop includes a master latch outputting a first signal which is generated based on a signal inputted through an input terminal based on first control signals; a slave latch outputting a second signal generated based on the first signal based on the first control signals and second control signals; and a control logic that generates the first control signals based on a clock signal and provides the first control signals to the master latch and the slave latch, and generates the second control signals based on a power down signal and provides the second control signals to the slave latch. The slave latch comprises a retention latch which transmits the first signal to an output terminal as the second signal by operating as an open loop based on the second control signals or maintains the second signal by forming a closed loop based on the second control signals.

Growing community of inventors

Gwangju-si, South Korea

Wanchul Kong