National Taiwan University

King Billion Electronics Co., Ltd.

Sheng-Lyang Jang

Yun-Hsueh Chuang

Cheng-Chen Liu

Shao-Hwa Lee

Shao-Hua Lee

Ren-Hong Yen

Chia-Wei Chang

James C Liu

Yi-Jhe Song

Jui-Cheng Han

Yu-Sheng Chen

Chung-Ching Chiu

Chun-Chieh Chao

Yun-Hsueh Chang

Jimmy Hsieh

Chien-Feng Lee

Hsueh-Ming Lu

An injection-locked frequency dividing apparatus including a frequency multiplier, a first linear mixer, a second linear mixer, and an oscillator is disclosed. The frequency multiplier receives a frequency signal and generates a multiple-frequency signal accordingly. The first and the second linear mixer both receive the multiple-frequency signal and respectively receive a first input signal and a second input signal, wherein the phases of the first and the second input signal are complementary. The first and the second linear mixer respectively mix the multiple-frequency signal with the first and the second input signal to respectively generate a first mixed signal and a second mixed signal. The oscillator generates the frequency signal. The oscillator further receives the first and the second mixed signal and generates a first output signal and a second output signal accordingly, wherein the phases of the first and the second output signal are complementary.

Injection-locked frequency dividing apparatus

A VCO comprising a cross-coupled transistors module and a resonant module is provided. The resonant module comprises a first transistor, second transistor, a first inductor and varactor string and a second inductor and varactor string. The first source/drain terminal of the first transistor coupled to the second reference voltage, the second source/drain terminal of the first transistor coupled to the cross-coupled transistors module and the gate terminal coupled to a bias voltage. The first source/drain terminal of the second transistor coupled to the second reference voltage, the second source/drain terminal of the second transistor coupled to the cross-coupled transistors module and the gate terminal of the second transistor coupled to the bias voltage. The first and second inductor and varactor strings coupled between the gate of the first and second transistors and a tuning voltage in serial, separately.

Multi-phase signal generator and voltage-controlled oscillator thereof

A multi-phase voltage-control oscillator including a first voltage-control oscillator circuit and a second voltage-control oscillator circuit is provided. The second voltage-control oscillator circuit and the first voltage-control oscillator circuit have a plurality of inductors, and the inductors in the second voltage-control oscillator circuit are respectively cross-coupled with the inductors in the first voltage-control oscillator circuit to generate a mutual inductance effect, so as to output a plurality of oscillating signals with different phases.

Multi-phase voltage-control oscillator

An injection-locked frequency divider for dividing a frequency of an injection signal and obtaining a frequency divided signal is provided. The injection-locked frequency divider includes a signal injection unit and an oscillator. The signal injection unit includes a first input terminal and a second input terminal for receiving the injection signal. The received injection signal exhibits a phase difference of 180&#xb0; between the first input terminal and the second input terminal. The oscillator includes an inductor unit and a variable capacitance unit. The injection-locked frequency divider is featured with a wide injection locking range, and can be realized with a low operation voltage, and therefore can be conveniently used in different kinds of hybrid ICs.

Injection-locked frequency divider

An injection-locked frequency divider includes a signal injection circuit and colpitts VCO. The signal injection circuit is for injecting an injection signal. The colpitts VCO includes first and second transistors, first and second LC tank circuits and a cross-coupled transistor pair. The first terminals of the first and second transistors receive the injection signal. The first and second LC tank circuits are for determining resonance frequency of an oscillation signal of the colpitts VCO. The cross-coupled transistor pair includes third and fourth transistors. The control terminals of the third and fourth transistors are respectively coupled to first terminals of the fourth and third transistors. The first terminals of the third and fourth transistors are respectively coupled to a first terminal or control terminal of the first and second transistors for providing an equivalent negative resistance. The injection signal and oscillation signal are mixed in frequency to generate differential output signals.

Injection-locked frequency divider with a wide injection-locked frequency range

An injection-locked frequency divider includes a ring oscillator, a signal injection circuit, a first adjustable load circuit and a second adjustable load circuit. The ring oscillator generates an oscillation signal according to a differential signal outputted by the signal injection circuit. According to an adjustable voltage, the first and second adjustable load circuits can respectively change equivalent impedances of the first adjustable load circuit and the second adjustable load circuit so that a free-running frequency of the oscillation signal of the ring oscillator is adjusted and an injection-locked frequency range of the injection-locked frequency divider is expanded.

An injection-locked frequency divider is provided. The injection-locked frequency divider includes an active inductor unit, a source injection unit, a first transistor and a second transistor. The injection-locked frequency divider generates a frequency-divided signal having a half frequency of the signal source. A locking frequency range of the injection-locked frequency divider is determined by a quality factor of a resonant cavity. A quality factor of the active inductor unit is lower than a conventional spiral inductor because the active inductor unit is composed of active elements. In the injection-locked frequency divider, the active inductor unit is used to instead of the conventional spiral inductor, so that the chip area can be reduced and the locking frequency range of the injection-locked frequency divider can be increased. Further, an induction value of the active inductor unit can be altered to change the locking frequency range of the injection-locked frequency divider.

Injection-locked frequency divider embedded an active inductor

An injection-locked frequency divider is provided. The injection-locked frequency divider includes a voltage control oscillator (VCO) and a mixer. The VCO includes a LC resonance tank and a negative-resistance generator for generating a differential oscillation signal including a first and a second oscillation signals. The LC resonance tank adjusts a VCO reactance and resonates for generating the differential oscillation signal. The negative-resistance generator coupled to the LC resonance tank eliminates an equivalent resistance generated by the LC resonance tank and maintains the VCO to continuously oscillate. The mixer has a first and a second local input terminals respectively receiving the first and second injected signals included in a differential injected signal, and the first and second radio frequency input terminals respectively receiving the first and second oscillation signals for mixing the differential injected signal with the differential oscillation signal to adjust the output frequency of the differential oscillation signal.

An injection-locked frequency divider is provided. The injection-locked frequency divider includes a variable reactance unit, a signal injection unit, a first switch, a second switch, a first transformer, and a second transformer. The variable reactance unit, the first switch, the second switch, the first transformer, and the second transformer form a transformer-based LC-tank oscillator. The signal injection unit receives an injection signal. When the injection-locked frequency divider is in a locked state, the transformer-based LC-tank oscillator outputs a frequency division signal. Employing the feedback action of the first transformer and the second transformer, the present invention not only has a wide locking range but also promotes the realization of the low operating voltage.

A multi-phase voltage-control oscillator including a first voltage-control oscillator circuit and a second voltage-control oscillator circuit is provided. The first voltage-control oscillator circuit includes a first LC tank and a first inductor assembly unit. The second voltage-control oscillator circuit includes a second LC tank and a second inductor assembly unit. A mutual inductance effect is generated between the inductors of the first voltage-control oscillator and the inductors of the second voltage-control oscillator.

A voltage control oscillator (VCO) includes a VCO circuit and a back-gate coupling circuit, wherein the VCO circuit includes at least a first transistor, a second transistor and a resonant cavity formed by an inductor and a capacitor. The back-gate coupling circuit is formed by a plurality of capacitors and a plurality of resistors. In the embodiments of the present invention, the capacitors are coupled to the back-gate terminals of the first transistor and the second transistor, so as to reduce the power consumption and the phase noise of the VCO.

Back-gate coupling voltage control oscillator

An injection locked frequency divider includes a signal injection unit, a Hartley voltage controlled oscillator and a biasing unit. The signal injection unit and the biasing unit output an injection signal to the Hartley voltage controlled oscillator to bias the Hartley voltage controlled oscillator. The Hartley voltage controlled oscillator, which includes a first transistor, a second transistor and a LC tank, receives the injection signal and outputs a differential output signal through a first output terminal and a second output terminal. First terminals of the first and second transistors are respectively coupled to the first and second output terminals, and second terminals of the first and second transistors are coupled to a first node. The LC tank decides a resonant frequency of the Hartley voltage controlled oscillator and serves as a positive feedback circuit for the first and second transistors.

Injection locked frequency divider

An injection locked frequency divider includes a ring oscillator, a first injection unit and a second injection unit. The ring oscillator includes a first delay cell and a second delay cell each including differential input terminals and differential output terminals. The differential input terminals and the differential output terminals of the first delay cell are respectively coupled to the differential output terminals and the differential input terminals of the second delay cell. The first injection unit connected between the differential output terminals of the first delay cell receives and injects a first injection signal to the differential output terminals of the first delay cell. The second injection unit connected between the differential output terminals of the second delay cell receives and injects a second injection signal to the differential output terminals of the second delay cell.

Injection locker frequency divider

The present invention is related with a dual-band LC voltage controlled oscillator, which utilizes a substantial amount of feedback loop paths in the circuit. The circuit is a core of a substantial amount of communication ICs. The voltage controlled oscillator can provide wide-band or dual-band radio frequency generation, and it utilizes a switch controlled circuit to select one of the feedback loops in order to choose the assigned frequency band output. Generic wide-band or dual-band LC voltage controlled oscillations are obtained by switching parallel-connected capacitors or switching inductor array, in contrast, the present invention is used for switching several parallel connected feedback loops, each of which associated with an LC tank forms an oscillation frequency output. Utilizing the switch to control the feedback loop and integrating different band oscillator circuit is capable of saving chip's size and power consumption.

Dual-band voltage controlled oscillator utilizing switched feedback technology

A latch-up-free ESD protection circuit using SCR is disclosed, in which an SCR is connected between the input pad and the negative power supply; a turn-on switch and a turn-off switch are connected between the positive power supply V(or the input pad) and the SCR; and a transistor gating circuit is connected to the turn-on switch and the turn-off switch to direct the operation of the SCR. When overvoltage stress develops over the input pad in the fast-transient mode, the turn-on switch enables the NPN transistor to switch on the SCR to form a discharging path for electrostatic discharge; and when overvoltage stress is released, the turn-off switch enables the PNP transistor to switch off the SCR, thus making it immune to any latch-up after the overvoltage stress is released, and having the advantages of fast triggering, low trigger voltage, no latch-up, and full ESD protection in the active and passive modes.

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Taipei, Taiwan

Sheng-Lyang Jang