Samsung Electronics Co., Ltd.

Je-Kwang Cho

Jin-Hyuck Yu

A frequency fine tuning circuit for use in a voltage-controlled oscillator is provided. The frequency tuning circuit includes a first varactor, a second varactor and a center bias unit. The second varactor is coupled to the first varactor at a first node. The center bias unit maintains a node voltage of the first node at a constant bias voltage level.

Frequency tuning circuits and voltage-controlled oscillator including the same

A capacitor bank includes a first node, a second node, first blocking capacitors, N first AMOS varactors, second blocking capacitors and N second AMOS varactors. The first blocking capacitors have first terminals connected to the first node and second terminals where a bias voltage is applied. The N first AMOS varactors have first terminals connected to the second terminals of the first block capacitors. The second blocking capacitors have first terminals connected to the second node and second terminals where the bias voltage is applied. The N second AMOS varactors have first terminals connected to the second terminals of the second blocking capacitors and second terminals connected to second terminals of the first AMOS varactors, respectively, wherein N binary coded signals are applied to the respective second terminals of the first AMOS varactors and the second AMOS varactors. Therefore, phase-noise degradation caused by the FM modulation may be avoided.

Growing community of inventors

Seongnam-si, South Korea

Je-Kwang Cho