Cisco Technology, Inc.

Bibhu Prasad Das

Kadaba Lakshmikumar

Romesh Kumar Nandwana

Bipin Dama

Abhishek Bhat

Alexander Christopher Kurylak

Pavan Kumar Hanumolu

Richard Van Hoesen Booth

Mark Y Tse

A charge-pump based low dropout (LDO) regulator is provided that overcomes latch-up issues. The LDO regulator is a high PSR low noise LDO regulator that uses a latch-up mitigated charge-pump voltage doubler which includes a N-type metal-oxide-semiconductor field-effect transistor (MOSFET), NMOS, pass transistor. This LDO regulator architecture may be used to provide a very low-noise supply regulated output voltage with high power supply rejection for an on-chip low jitter oscillator. Latch-up is mitigated using control circuitry and a power supply timing sequence. This scheme ensures that parasitic diodes associated with various transistors in the regulator are not forward biased.

Latch-up mitigated charge pump for high power supply rejection low-dropout regulator

An apparatus includes a delta-sigma modulator digital-to-analog converter section having a multiple stag cascaded error cancellation architecture, each stage including a delta-sigma modulator followed by a digital-to-analog converter, the delta-sigma modulator digital-to-analog converter section configured to receive a digital input and to generate an analog output. An inverting amplifier-based analog filter is coupled to receive the analog output, the inverting amplifier-based analog filter configured to filter the analog output to produce a filtered analog output.

Error cancellation delta-sigma DAC with an inverting amplifier-based filter

A system includes a transimpedance amplifier, disposed on a chip, having a front-end section and a back-end section; an on-chip linear regulator, on the chip, arranged to power the front-end section; and an off-chip switching regulator, off the chip, arranged to power the back-end section. The arrangement provides low noise power supply for the front-end section, while providing a more power efficient switching regulator to power the back-end section. The output voltage of the on-chip linear regulator and the output voltage of the off-chip switching regulator are controlled to be the same.

Linear transimpedance amplifier dual regulator architecture and tuning

Embodiments herein describe a reference-less CDR circuit that receives electrical signals that may have been transmitted along either an electrical or optical interconnect which are then processed to identify the original data. To do so, the CDR circuit includes a frequency locking loop (FLL) and a phase locking loop (PLL) which generate control signals for a voltage controlled oscillator (VCO). In one embodiment, the FLL generates a coarse adjustment signal which the VCO uses to output a recovered clock that substantially matches the frequency of the received electrical signal. The PLL, on the other hand, generates a fine adjustment signal which the VCO uses to make small adjustments (e.g., half cycle phase shifts) to the recovered clock. The recovered clock outputted by the VCO is then fed back and used as an input in both the FLL and the PLL.

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Allentown, PA, United States of America

Bibhu Prasad Das