Pulsecore Semiconductor, Inc.

Other

Alliance Semiconductor Corporation

On Semiconductor Trading, Ltd.

Capella Microsystems Inc.

Dan I Hariton

Narendar Venugopal

Dipankar Mandal

Gautam K Singh

Anthony Lau

Sushl Kumar

Werner Hoeft

Santosh K Panigrahi

Duoc Nguyen

Sushil Kumar

A method for applying spread spectrum noise reduction techniques to USB specifically USB2.0 communications systems includes the step of generating a base (seed) frequency for the USB system, modulating the base (seed) frequency with a spread spectrum (SS) characteristic, and utilizing (as-is, not modified) the existing ASIC that multiplying the now modulated base (seed) frequency to generate the USB standard frequency signaling rate of 480 MHz with the SS characteristic within the USB standard specification for frequency deviation.

USB system with spread spectrum EMI reduction

A method and apparatus for frequency modulating a PWM involves 1) generating a high frequency carrier signal much greater in frequency than the PWM signal; 2) modulating the high frequency signal to generate a spread spectrum carrier signal; and, 3) retiming a PWM signal with this high frequency SS carrier signal so that the binary transitions of the PWM signal are aligned with the frequency varying carrier signal. In another embodiment, a PWM oscillator is driven by a second, FM oscillator having spread spectrum characteristics. In another embodiment a PWM oscillator is driven and modulated by a counter/frequency divider comprised of modules.

Method and apparatus for frequency modulating a periodic signal of varying duty cycle

A controllable delay clock buffer that provides spread spectrum modulation of the output signals with zero cycle slip includes a PLL having a PLL loop filter that comprises an RC network. A clock signal is input to the PLL, and a SS modulation frequency is injected into the capacitor of the PLL loop filter. The SS signal is provided by a secondary charge pump that produces a programmable waveform such as a square wave or a stair case square wave current signal. The programmable waveform is integrated by the loop filter capacitor to form a corresponding triangular or trigonal waveform which varies the input to the VCO of the PLL to define a frequency modulation profile that has a corresponding triangular or trigonal envelope. The bandpass profile of the SS modulation signal is at a higher frequency range than the lowpass profile of the PLL, so that the SS waveform profile is not distorted or cancelled by the PLL.

Spread spectrum controllable delay clock buffer with zero cycle slip

A method and device to emulate impedances includes a pair of impedances connected in series between two circuit nodes, the impedances forming a voltage divider having at its midpoint a reference voltage V . An OP AMP includes a positive input connected to the V node and the negative input connected to the output thereof in a direct feedback loop. The OP AMP output is also connected to a load impedance that is connected either one of the nodes. A transistor may be interposed between the load impedance and the circuit node. The OP AMP may be provided with a negative gain to emulate an inductor. The voltage divider may be variable to emulate a variable impedance.

Impedance emulator

A dual function circuit for providing an output voltage to a transimpedance amplifier is disclosed. The dual function circuit can be selected between functioning as a current to voltage conversion circuit connected to a photodiode and as a testing circuit for testing the transimpedance amplifier without exposing light to the photodiode. The dual function circuit comprises two current mirror pairs to ensure that a substantially similar dc bias current is applied to the two driving transistors. In addition, by applying an input testing voltage to the two driving transistors in a common gate/base design, the output of the testing circuit has wide band frequency response. No switching is required to select between the test mode and the normal mode.

BIST for testing a current-voltage conversion amplifier

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Santa Clara, CA, United States of America

Dan I Hariton