United Microelectronics Corp.

National Taiwan University

Jen-Chung Chang

Chia-Jung Hsu

Shey-Shi Lu

Tzu-Chao Lin

Hsiao-Chin Chen

Yu-Che Yang

Yu-Yee Liow

Tsung-Chien Wu

Yu Cheng

Albert Kuo-Huei Yen

A frequency-converting circuit and a down converter with the frequency-converting circuit are disclosed. The above-mentioned frequency-converting circuit is used for converting an RF signal into a first baseband signal according to a poly-phase LO signal. The frequency-converting circuit includes a coupler, a first transduction unit and a first switching unit. The coupler is for receiving and splitting the RF signal and delivering a first RF signal via the first output terminal thereof. The first transduction unit is for amplifying the first RF signal. The first switching unit is for performing switching operations on the output signal of the first transduction unit and producing the first baseband signal.

Frequency-converting circuit and down converter with the same

In a phase locked loop (PLL), phase shifters shift a phase of an input signal. Based on the phases of the input signal, the shifted signals, and a frequency division output signal, phase frequency detectors (PFDs) generate phase difference signals. In response to the phase difference signals, charge pumps (CPs) control output voltages thereof. Based on the output voltages of the CPs, a voltage controlled oscillator (VCO) outputs an output signal. A frequency divider divides the frequency of the output signal from the VCO to generate the frequency division output signal. A circulator outputs the frequency division output signal to one of the PFDs at a proper timing. A modulator reduces quantization errors of the frequency divider.

Phase locked loop with phase shifted input

Provided is a distributed amplifier in communication systems, including: an input transmission line; an output transmission line; an input impedance match and an output impedance match, for providing termination of the input transmission line and the output transmission line, respectively and for preventing signal reflection in the input transmission line and the output transmission line, respectively; multi-stage Gm cells with common mode feedback, the input transmission line being coupled to the output transmission line by the transconductance of the Gm cells; and an input gate bias circuit, for providing bias for the multi-stage Gm cells. In at least one of the Gm cells, one inverter performs V/I conversion while other inverters provide negative resistance to control common mode of output voltage and to enhance DC gain of the Gm cell. Due to common mode feedback, no output gate bias is needed.

Low power comsumption, low noise and high power gain distributed amplifiers for communication systems

A sub-harmonic mixer and a down converter with the sub-harmonic mixer are provided. The sub-harmonic mixer includes a differential amplifying unit, a current buffer unit, and a switching unit. The differential amplifying unit is used to amplify a radio frequency (RF) signal and employs a first resonance circuit to force a leakage signal to flow to a first voltage. The current buffer unit is used to amplify the gain of an output signal of the differential amplifying unit and employs a second resonance circuit to force the leakage signal to flow to a second voltage. Finally, the switching unit switches an output signal of the current buffer unit into a base band signal.

Sub-harmonic mixer and down converter with the same

Growing community of inventors

Taoyuan County, Taiwan

Jen-Chung Chang