Silicon Laboratories Inc.

Akhil K Garlapati

Bruce Philip Del Signore

Axel Thomsen

Douglas F Pastorello

David M Pietruszynski

Lizhong Sun

Jerrell P Hein

Richard J Juhn

An integrated circuit includes USB communication circuitry for communicating via a USB interface. The USB transceiver circuitry transmits data to and from the integrated circuit over the USB interface. The USB transceiver circuitry further provides protection to internal circuitry of the integrated circuit from a 5 volt short circuit on the USB interface.

USB transceiver circuitry including 5 volt tolerance protection

A method for dividing a signal having a first frequency by a divide ratio includes selecting, based on the divide ratio, a first pulse width of at least one signal having a second frequency and being generated by at least a corresponding one of a plurality of pulse-width control circuits responsive to at least one signal having a second pulse width. The method includes selecting at least one of the plurality of pulse-width control circuits to be powered-on to generate the at least one signal. The at least one of the plurality of pulse-width control circuits includes a first pulse-width control circuit to generate a first signal having the first pulse-width, second frequency, and first phase. The first signal corresponds to a select circuit output signal having a first phase. The method includes selecting at least one other of the plurality of pulse-width control circuits to be powered-off.

High-speed divider with reduced power consumption

In at least one embodiment of the invention, a method for dividing a first signal having a first frequency by a divide ratio to generate a lower frequency signal includes generating a first plurality of signals having a common frequency, a first pulse width, and different phases. The first plurality of signals is based, at least in part, on at least one signal having a second pulse width. The first pulse width is selected from a plurality of pulse widths based, at least in part, on the divide ratio. The method includes sequentially selecting individual pulses of the first plurality of signals as an output signal of a select circuit to generate an output signal having a frequency lower than the first frequency.

High-speed divider with pulse-width control

A complementary metal-oxide semiconductor output driver provides a differential output signal having a particular differential voltage swing and a particular common mode voltage to a differential output node for various types of load circuits coupled to the differential output node. The load circuit may have any impedance within a particular impedance range. A current source provides a current with a variable current component that adjusts the differential voltage swing of the differential output signal. A common mode feedback circuit adjusts the common mode voltage of the differential output signal by sourcing current to the differential output node or sinking current from the differential output node. At least a portion of a current flowing into a load circuit coupled to the differential node is provided by the current source, thereby reusing current from the current source.

Output driver with common mode feedback

A voltage reference generator has been discovered that generates a stable reference voltage that is less than the bandgap voltage of silicon for power supply voltages less than 2V, yet provides sufficient voltage headroom to operate a cascaded current mirror. In one embodiment, the voltage reference generator has a power supply rejection ratio of at least 60 dB and has improved noise performance as compared to traditional bandgap circuits. These advantages are achieved by leveraging the low-beta effect of a CMOS bipolar transistor to generate a current proportional to an absolute temperature.

Voltage reference generator circuit using low-beta effect of a CMOS bipolar transistor

A voltage reference generator generates a stable reference voltage that is less than the bandgap voltage of silicon for power supply voltages less than 2V, yet provides sufficient voltage headroom to operate a current mirror. In one embodiment, the voltage reference generator has a power supply rejection ratio of at least 60 dB and has comparable noise performance as compared to traditional bandgap cirucits. These advantages are achieved by subtracting a current proportional to a complement of an absolute temperature from a current proportional to the absolute temperature to generate a voltage having a positive temperature coefficient, which is then added to a voltage that is a complement of the absolute temperature to achieve a voltage that has a low temperature coefficient.

Voltage reference generator circuit subtracting CTAT current from PTAT current

An output buffer circuit drives multiple signal formats. The output buffer circuit reduces duplication of output bond pads on an integrated circuit die. The output buffer circuit reduces a need for including conversion buffers on system boards. A single integrated circuit including the output buffer circuit may meet a variety of applications. The output buffer achieves these results with a programmable output voltage swing and a programmable output common mode voltage. In some embodiments of the present invention, an integrated circuit includes at least one single-ended buffer and at least one differential circuit coupled to a pair of outputs. One of the single-ended buffer and the differential circuit is selectively enabled to provide a signal to the outputs.

Growing community of inventors

Boston, MA, United States of America

Akhil K Garlapati