Ememory Technology Inc.

Wei-Yao Lin

Shao-Chang Huang

Kun-Wei Chang

Tang-Lung Lee

Tsung-Mu Lai

Wen-Hao Lee

Yu-Chun Chang

Mao-Shu Hsu

Lin-Fwu Chen

Luan-Yi Yen

A driver circuit has a pad that may be utilized for programming a core circuit or receiving a data signal. A trace high circuit receives a pad voltage signal from the pad, and outputs a trace high voltage approximating a higher voltage of the pad voltage signal and the power supply voltage. A level shifter and a first inverter output a pull high control signal generated by inverting and level shifting a programming control signal. An ESD blocking circuit selectively blocks the pad voltage signal from reaching the core circuit depending on the pad voltage signal and the level-shifted programming control signal. A pull high circuit receives the pull high control signal and the power supply voltage, and outputs the power supply voltage to the core circuit when the pull high control signal is lower than the power supply voltage.

Power switch embedded in ESD PAD

A high-voltage selecting circuit generates an output voltage with no voltage drop by means of an auxiliary NMOS transistor turning on the corresponding selecting PMOS transistor of the high-voltage selecting circuit when the voltage levels of a first input voltage and a second input voltage are equal. In addition, when one of the first input voltage and the second input voltage is higher than the other one, the high-voltage selecting circuit avoids the leakage current by means of an auxiliary PMOS transistor turning off the corresponding selecting PMOS transistor of the high-voltage selecting circuit. In this way, the high-voltage selecting circuit can correctly generate the output voltage according to the first input voltage and the second input voltage, and avoid the leakage current at the same time.

High-voltage selecting circuit which can generate an output voltage without a voltage drop

A high voltage tolerance circuit includes a first transistor, a second transistor, a third transistor, and a latch-up device. The first transistor and the second transistor are controlled by a control signal. The gate of the third transistor is coupled to a ground through the first transistor. The gate of the third transistor is coupled to an I/O pad through the second transistor. The third transistor is coupled between a power supply and a node. The latch-up device is coupled between the node and the I/O pad.

High voltage tolerance circuit

An electrostatic discharge (ESD) protection circuit is electrically connected to a core circuit for preventing ESD charges from reaching the core circuit. The ESD protection circuit includes a pad, a pass transistor, a transistor, a capacitor, a resistor, and a delay trigger unit. The pass transistor controls passage of charges from the pad to the core circuit. The transistor sinks ESD charges during an ESD zapping event. The capacitor and the resistor couple voltage at the pad to a control electrode of the transistor for turning on the transistor during the ESD zapping event. The delay trigger unit retards transmission of low voltage to a control electrode of the pass transistor for keeping the pass transistor turned off during the ESD zapping event.

Growing community of inventors

Hsinchu County, Taiwan

Wei-Yao Lin