Abstract:
A dual-band voltage controlled oscillator (VCO) includes: a first oscillator circuit including a first inductor; a second oscillator circuit including a second inductor; a first mode switch configured to electrically connect or disconnect a first output terminal of the first oscillator circuit and a first output terminal of the second oscillator circuit; a second mode switch configured to electrically connect or disconnect a second output terminal of the first oscillator circuit and a second output terminal of the second oscillator circuit; a third mode switch configured to electrically connect or disconnect a first terminal of the first inductor and a first terminal of the second inductor; and a fourth mode switch configured to electrically connect or disconnect a second terminal of the first inductor and a second terminal of the second inductor.
Abstract:
A novel and useful LC-tank digitally controlled oscillator (DCO) incorporating a split transformer configuration. The LC-tank oscillator exhibits a significant reduction in area such that it is comparable in size to conventional ring oscillators (ROs) while still retaining its salient features of excellent phase noise and low sensitivity to supply variations. The oscillator incorporates an ultra-compact split transformer topology that is less susceptible to common-mode electromagnetic interference than regular high-Q LC tanks which is highly desirable in SoC environments. The oscillator, together with a novel dc-coupled buffer, can be incorporated within a wide range of circuit applications, including clock generators and an all-digital phase-locked loop (ADPLL) intended for wireline applications.
Abstract:
Circuit (1) of a voltage controlled oscillator comprising: - a bridge structure including two cross-coupled transistors of N type (M 3 , M 4 ) and two cross-coupled transistors of P type (M 5 , M 6 ); - a current mirror (3) connected to the two cross-coupled transistors of N type (M 3 , M 4 ) and arranged to generate a bias current (I B ) for the circuit (1); - an LC resonator (2) placed in parallel between the two cross-coupled transistors of N type (M 3 , M 4 ) and the two cross-coupled transistors of P type (M 5 , M 6 ). The circuit (1) is characterised in that the LC resonator (2) comprises: two pairs of differential inductors (L 1 , L 2 ) mutually coupled by means of a mutual inductance coefficient (M), each pair comprising a first inductor (L 1 ) arranged on a respective branch (10a) of an external loop, and a second inductor (L 2 ) arranged on a respective branch (12a) of an internal loop; a first varactor (C v33 ) connected to a common node (A) and to a first branch (12a) of the internal loop; a second varactor (C v33 ) connected to the common node (A) and to a second branch (12a) of the internal loop.
Abstract:
Oscillating device comprising several oscillators (OSC1, OSC2), each oscillator comprising a capacitive inductive resonant circuit (L 1 & C1, L2 & C2) and a flow-through conduction circuit (G1, G2) having a negative flow-through conduction, the inductive elements of the oscillators being mutually coupled. Each oscillator also comprises a controllable switch (INT 1, INT2) arranged in order to short-circuit or not short-circuit the capacitive element of the oscillator (C1, C2) and in that the device also comprises controllable commutating means (STOP1, ST0P2) arranged to activate one oscillator at a time.
Abstract:
The present disclosure relates to coupled circuits and methods of coupling circuits having a power supply wherein a plurality of transistors are inductively coupled directly to the power supply for providing a single DC supply voltage directly to each of the plurality of transistors, and wherein a plurality of transformers have primary and secondary windings, the primary and secondary windings providing, at least in part, inductive loads for inductively coupling the plurality of transistors to the power supply, the plurality of transformers also providing an AC signal path for coupling neighboring ones of the plurality of transistors together.
Abstract:
A multi-band VCO employs a coupled-inductor based resonator having ports. Each port has an inductor and at least one capacitor. The N inductors for the N ports are magnetically coupled. The inductors/ports may be selectively enabled and disabled to allow the VCO to operate at different frequency bands. The capacitor(s) for each port may include one or more fixed capacitors, one or more variable capacitors (varactors), one or more switchable capacitors, or any combination of fixed, variable, and switchable capacitors. The switchable capacitors (if any) in the enabled ports may be selectively enabled and disabled to vary the VCO oscillation frequency. The varactors (if any) in the enabled ports can vary the oscillation frequency to lock the VCO to a desired frequency. The multi-band VCO may be implemented with various oscillator topologies and can replace multiple single-band VCOs.
Abstract:
A junction field effect transistor (JFET) RF oscillator-detector circuit generates an RF signal for an apparatus for conducting electrical measurements of particles contained in a carrier fluid passing through an aperture in a cytometer flow cell. The JFET oscillator includes a plurality of parallel-coupled JFETs having respectively different VDS vs. IDS characteristics, that are biased to operate at square law detection regions of their respective VDS vs. IDS characteristics. One JFET operates in Class C mode, while the other operates in Class AB mode. An RF resonant circuit is electrically coupled to the JFETs and to the measurement cell, and is operative to establish the frequency of an RF field applied to the measurement cell. An RF load change detection circuit is coupled to the RF resonator circuit and is operative to detect an RF load change associated with a modification of the RF field as a result of a particle within the measurement cell aperture.
Abstract:
An automatic voltage-controlled oscillator (VCO) current control circuit (100, 200, 300 or 400) that senses a voltage in the VCO (201) representative of the current of the VCO (201), compares that voltage (V2) to a reference voltage (V1), and applies the voltage (V3) resulting from that comparison back to the VCO (201) at a point therein that changes its bias state in such a manner as to maintain the noise level in the VCO at a minimum and also maintains the power output of the oscillator substantially constant.
Abstract:
The invention relates to a resonator circuit (100), the resonator circuit (100) comprising a transformer (101) comprising a primary winding (103) and a secondary winding (105), wherein the primary winding (103) is inductively coupled with the secondary winding (105), a primary capacitor (107) being connected to the primary winding (103), the primary capacitor (107) and the primary winding (103) forming a primary circuit, and a secondary capacitor (109) being connected to the secondary winding (105), the secondary capacitor (109) and the secondary winding (105) forming a secondary circuit, wherein the resonator circuit (100) has a common mode resonance frequency at an excitation of the primary circuit in a common mode, wherein the resonator circuit (100) has a differential mode resonance frequency at an excitation of the primary circuit in a differential mode, and wherein the common mode resonance frequency is different from the differential mode resonance frequency.
Abstract:
A transformer is described. The transformer includes a primary coil and a first secondary coil. A first coupling occurs between the first secondary coil and the primary coil. The transformer also includes a second secondary coil. A second coupling occurs between the second secondary coil and the primary coil. The first secondary coil is separated from the second secondary coil to prevent coupling between the first secondary coil and the second secondary coil. A first width of the first secondary coil is configured independently of a second width of the second secondary coil.