Electronics and Telecommunications Research Institute

Industry-University Cooperation Foundation Hanyang University

Yea Chul Roh

Chang Sun Kim

Oh-Kyong Kwon

Seong Hoon Choi

Tae-Yeoul Yun

Jang Hyun Park

Hee-woo An

Yun-mo Kang

Provided are a touch screen and a method for compensating sensing capacitance variations and offset variations thereof. The touch screen includes: a touch panel where a plurality of driving lines and a plurality of sensing lines intersect and are wired; a driving unit for activating the driving lines sequentially; an input unit for measuring a sensing capacitance formed in a sensing line corresponding to an activated driving line; a multiplexer for serializing and outputting the measured sensing capacitance; an analog-to-digital converter for sampling the sensing capacitance outputted from the multiplexer by reflecting an initial sensing capacitance as an offset and performing analog-to-digital conversion for the sampling result; and a host processor for determining a touch event in response to the analog-to-digital conversion result.

Touch screen and method for compensating sensing capacitance variations and offset variations thereof

Provided is a frequency conversion mixer. The frequency conversion mixer includes a transconductance stage, a switching stage, a load stage, a current bleeding circuit, and a bias stage. The transconductance stage receives an RF signal, and outputs a current corresponding to a voltage of the RF signal. The switching stage switches the current which is outputted from the transconductance stage in response to a local oscillation signal, for frequency conversion the RF signal into an intermediate frequency (IF) signal. The load stage is connected between the switching stage and a supply voltage terminal. The current bleeding circuit is connected parallel with the switching stage, especially, embodying inverter structure with transconductance stage to get not only current bleeding effect but also current reuse effect, and one resonant inductor for reducing noise which is generated in parasitic capacitance at node between transconductance stage and switching stage. The bias stage is connected between the transconductance stage and a ground terminal, and has the switched biasing technique for allowing not only the stable bias current but also lowering the flicker noise.

Frequency conversion mixer

Growing community of inventors

Seongnam, South Korea

Yea Chul Roh