41results about How to "Reduce Noise Sensitivity" patented technology

A constant ON-time controller for a buck converter utilizes dual symmetrical ramps. The ramps may be generated artificially or by sensing the voltage across a sense resistor in the output. The ramp may also be generated by sensing the voltage across the “ON” resistance of the low side FET in the switching regulator. A modified output voltage has one of the ramps superimposed and a modified reference voltage has the other ramps superimposed. The modified output voltage and the modified reference voltage are compared to determine when to start the ON-time of the buck converter. The dual ramps reduce, noise susceptibility. The ON-time is stopped in response to charging a capacitor with the regulator input voltage. An offset may also be generated representing the difference between the average output voltage and the reference voltage. The offset is used to generate a modified reference to compensate for the offset.

A digital audio system including a digital phase-locked-loop circuit for generating a pulse-width-modulation (PWM) clock signal, applied to a pulse-code-modulation to pulse-width-modulation converter, is disclosed. The digital phase-locked loop includes a phase detector for measuring phase error between a reference signal and a feedback signal. A digital version of the phase error, after filtering by a loop filter, is converted to a digital delay control word that is sampled at twice its frequency. Successive samples of the delay control word control the propagation delay of first and second delay cells in an oscillator. The use of successive samples at substantially twice the frequency of change of the delay control word effectively realizes the sum of a sinc filter and a comb filter, which greatly suppresses the effects of jitter in the reference signal to the digital phase-locked loop.

The invention provides a low-voltage power supply multi-path output power comprising a filtration circuit, a power conversion circuit, an output rectification high-frequency filtration circuit, a low differential voltage stabilizer, a sampling circuit, a feedback isolation circuit, a control circuit and a self-start and auxiliary power circuit. The filtration circuit, the power conversion circuit, the output rectification high-frequency filtration circuit and the low differential voltage stabilizer are electrically connected in sequence; the sampling circuit is connected to the output rectification high-frequency filtration circuit; the feedback isolation circuit is connected to the sampling circuit; the control circuit is arranged between the feedback isolation circuit and the power conversion circuit; the self-start and auxiliary power circuit are connected into the control circuit; the power conversion circuit is a single-end forward power conversion circuit; and the control circuit is a current control-type pulse width modulation circuit in the third generation of CMOS(Complementary Metal Oxide Semiconductor) technology. The invention solves the technical problems of complex design and low stability of a peripheral circuit of the traditional modulator and has the advantages of reasonable design, high practicability, and the like.

An electronic device for a lighting system, comprising a TRIAC dimmer configured to receive a mains supply voltage and provide a phase cut voltage to the electronic device and having a control loop configured to control a duty cycle of a switched voltage converter that receives the rectified input voltage and provides drive current to a light emitting semiconductor device. The control loop has an error amplifier that is coupled to receive a sense voltage that is indicative of a current through the light emitting semiconductor device, the error amplifier is configured to provide a feedback signal to a pulse width modulation logic configured to control the duty cycle of the switched voltage converter to provide a constant drive current to the light emitting semiconductor device in response to the sense voltage, the error amplifier being coupled to receive a reference voltage that is a function of the input voltage.

An electrical oscillator circuit comprising: a resonator comprised in the first subcircuit; and an active device comprised in the second subcircuit connected to energize the resonator to provide an oscillating electrical signal transmitted as a differential signal via electrical conductors to the second subcircuit. The oscillator is characterized in that the second subcircuit comprises means for receiving the differential signal transmitted via the electrical conductors and converting the differential signal to a single-ended signal with reference to the signal ground reference of the second subcircuit. Thereby a noise robust oscillator signal is provided with the use of very few components. Particularly suitable for oscillators embodied in an integrated circuit with the resonator mounted on a printed circuit board, PCB. And an integrated circuit.

The invention discloses a square wave transformation amplitude measuring device based on self-mixing interference. The device comprises a light source unit, a signal processing unit and a data processing unit, wherein the signal processing unit introduces a hysteresis comparator to process signals so as to output required square wave signals, and the data processing unit searches for turning points for the output square wave signals so as to calculate the vibration amplitude of an object according to the number of fringes in the same inclined direction between adjacent turning points. The invention also discloses a square wave transformation amplitude measurement method based on self-mixing interference. According to the invention, the hysteresis comparator circuit with adjustable upper and lower limits is adopted to perform square wave transformation on an obtained laser self-mixing signal, so that the influence of external noise on the measurement stability and accuracy is effectively reduced. The self-mixing interference principle is adopted with no specific requirement on the coherence of the laser light source, so that the laser has large selection freedom. Meanwhile, the amplification factor of the signal is controllable, the measurable minimum amplitude value can reach a nanometer level, and wide-range real-time measurement is easy to realize.