Broadcom Corporation

Avago Technologies International Sales Pte. Limited

Jungwoo Song

Xicheng Jiang

Minsheng Wang

Lawrence M Burns

Agnes Woo

Donald George McMullin

Stephen A Jantzi

Anilkumar V Tammineedi

Todd Lee Brooks

Derek Tam

Takayuki Hayashi

Jasmine Cheng

Hui Zheng

Iuri Mehr

Vinay Chandrasekhar

I-Ning Ku

Chun-Ying Chen

Aravind Kumar Padyana

Chi Mo

Alex Jianzhong Chen

Junjie Lu

Jianlong Chen

Xiaofeng Lin

Jianhua Gan

Jing Guo

Sasi Kumar Arunachalam

Zhengyu Wang

Wynstan Tong

Darwin Cheung

Jingbo Duan

Kareem Abdelghani Ibraheem Mohamed Ragab

An apparatus includes a digital ramp generator comprising a delay line, the delay line comprising one or more delay elements and an oscillator, wherein the digital ramp generator is configured to generate a code based on respective outputs of the one or more delay elements, a digital to analog converter coupled to the digital ramp generator, wherein the digital to analog converter is configured to generate a reference signal, wherein the reference signal is generated based, at least in part, on the code, and a driver coupled to the digital to analog converter, the driver configured to generate a drive current based, at least in part, on the reference signal.

LED driver electromagnetic interference mitigation

A device (e.g., SAR ADC device) include a DAC circuit and generates a digital output based on logic circuitry that includes SAR logic. Additional logic circuitry includes delta modulation circuitry and dynamic element matching circuitry. The delta modulation circuitry provides several digital outputs of the SAR DAC, while the dynamic element matching circuitry selects a different set of capacitors from the DAC circuit. Each cycle is added together and averaged, and then added to the digital output from the SAR logic.

Incremental delta modulation for analog to digital converter signal to noise ratio and linearity enhancement

Systems, apparatuses, and methods provided for ping-pong charge pumps. Flying capacitors present in ping-pong charge pumps are operated out of phase to increase equalization periods. Out-of-phase operation also decreases voltage differences between flying capacitors during equalization periods thus decreasing ping-pong charge pump output voltage ripple and snapback. The voltages of the flying capacitors may be equalized without the use of an equalization switch. Differential control currents that are based on the voltage difference between the flying capacitors are used to enable or disable the flying capacitors from driving an output load of the ping-pong charge pump during certain phases of operation. A capacitor with a lower voltage may be disabled, thus providing for voltage equalization as the enabled capacitor sources current to the output load. The flying capacitors are also equalized during overlapping time periods in which the flying capacitors are charging.

System, apparatus, and method for a ping-pong charge pump

Methods, systems, and apparatuses for detecting and suppressing analog error in an output stage of a digital class-D amplifier are described. In embodiments, the digital class-D amplifier includes a PWM stage, an output stage, and a feedback circuit. The PWM stage receives the signal difference between an input digital signal and a feedback digital signal, generates a digital pulse-width modulated (PWM) signal based thereon, and provides the digital PWM signal as a first component of the digital feedback signal. The output stage receives the digital PWM signal and generates an analog output signal for driving a load responsive to the digital PWM signal. The feedback circuit combines an analog representation of the PWM signal and the analog output signal to generate a second component of the digital feedback signal.

Digital class-D amplifier with analog feedback

Systems and methods are disclosed to provide automatic power control for a driver circuit. Embodiments disclosed herein enable a driver circuit to automatically decrease the gain of amplified input signals when output power exceeds a threshold. Further, embodiments disclosed herein enable a driver circuit to automatically increase the gain of amplified input signals when battery supply voltage drops to avoid unwanted output signal distortion. By using reference signals for battery power and amplified signal input, the amplifiers of the driver circuit can be automatically adjusted until an equilibrium is reached.

Distortion limiter and automatic power control for drivers

A multi-mode line driver circuit designed to be fabricated in a CMOS process and capable of supporting a plurality of operating modes corresponding, for example, to different profiles of communication standards such as xDSL standards. The line driver circuit incorporates integrated mode switches with a two-stage amplifier architecture to relax amplifier requirements by distributing the signal gain into two amplifier stages. Reconfigurable feedback loops are provided to permit design optimization for particular modes of operation (e.g., ADSL and VDSL compliant modes). In one embodiment implemented as a Class-H amplifier, lift amplifier(s) are provided between a first amplifier stage and a second amplifier stage for controlling voltage supply levels of the second amplifier stage. The lift amplifiers may be enabled by voltage threshold detection circuitry that monitors either the input or the output signals of the first amplifier stage depending on the operable transmission mode.

Integrated CMOS multi-mode drivers

A noise reduction circuit for reducing the effects of low frequency noise such as wind noise in communications applications is described. In one embodiment, the noise reduction circuit features a high pass filter formed by exploiting the existing off-chip AC coupling capacitances in making the connection to the source of audio signals. The filter may be adaptive to environmental low frequency noise level through programming the shunt resistances. A low-noise wide dynamic range programmable gain amplifier is also described. Adaptive equalization of the audio signal is also described through the utilization of programmable front-end resistors and a back-end audio equalizer.

Low frequency noise reduction circuit architecture for communications applications

Disclosed is an amplifier circuit configured to amplify a pulse stream. The amplifier circuit comprises a switching block including a first switch operable to couple an output node of the switching block to a positive reference voltage, a second switch operable to couple the output node to a ground reference voltage and a third switch operable to couple the output node to a negative reference voltage. The amplifier circuit is configured to amplify the pulse stream into an amplified signal detectable at the output node such that the amplified signal has a common-mode voltage level substantially equal to zero volts. In one embodiment, the amplifier circuit is configured to amplify the pulse stream in accordance with a Class-D amplification scheme. In one embodiment, the output node can be directly connected to a load device without a DC blocking capacitor being interposed between the output node and the load device.

Ground-referenced common-mode amplifier circuit and related method

An upstream amplifier is integrated on a substrate with a digital-to-analog converter (DAC) to form an integrated circuit. In an embodiment, a low-pass filter is also integrated on the substrate. The output signal level of the upstream amplifier is controllable. In embodiments, fine adjustments are made to the output signal level of the upstream amplifier by varying a bias current of the DAC. A software control bit is used to switch between a power-on mode of operation and a power-down mode of operation. The upstream amplifier transmits in a burst mode. The power consumption of the upstream amplifier scales with the amplifier's output signal level. A high degree of matching is attained between the positive and negative paths of the upstream amplifier. This provides high immunity from common-mode disturbances such as substrate noise, clock spurs, and glitches caused by a gain change.

Integrated upstream amplifier for cable modem and cable set-top boxes

Disclosed is a switching amplifier having an enhanced supply rejection. The switching amplifier comprises a digital modulator that provides a modulated signal. The switching amplifier further comprises a closed-loop analog driver that is coupled to the digital modulator. As disclosed, the closed-loop analog driver is configured to re-modulate a modulation signal that corresponds to the modulated signal. An output stage of the switching amplifier is driven by the re-modulated signal, thereby providing enhanced supply rejection. In one embodiment, the modulated signal is produced by a digital pulse-width modulator (PWM) circuit of a Class-D amplifier, and has a pulse rate substantially less than a clock rate of the digital PWM circuit. In one embodiment, the switching amplifier is implemented as an audio amplifier in a mobile communication device such as a cellular telephone.

Switching amplifier with enhanced supply rejection and related method

Disclosed is a closed-loop class-D amplifier circuit including a modulated reference signal generator that provides a modulated reference signal in a feed-forward path, where the reference signal is modulated corresponding to an input signal. The closed-loop class-D amplifier circuit further includes a comparator to generate a control signal based on a comparison of the modulated reference signal and a correction signal, which in turn is produced by filtering a combination of the input signal and a feedback signal. The closed-loop class-D amplifier circuit also includes a pulse generator to generate a pulse-width-modulated signal to drive an output stage of the closed-loop class-D amplifier based on the control signal.

Closed-loop class-D amplifier with modulated reference signal and related method

A circuit with dielectric thicknesses is presented that includes a low-pass filter including one or more semiconductor devices having a thick gate oxide layer, while further semiconductor devices of the circuit have thin gate oxide layers. The low-pass filter semiconductor device includes an N-type substrate, a P-type region formed on the N-type substrate, a thick gate oxide layer formed over the P-type region, a Pgate electrode formed over the thick gate oxide layer and coupled to a first voltage supply line, and Ppick-up terminals formed in the P-type region adjacent the gate electrode and coupled to a second voltage supply line. The low-pass filter semiconductor device acts as a capacitor, whereby a gate-to-substrate voltage is maintained at less than zero volts to maintain a stable control voltage for the circuit.

Thick oxide P-gate NMOS capacitor for use in a low-pass filter of a circuit and method of making same

Integrated upstream amplifier for cable modems and cable set-top boxes

Provided is an amplifier including a system for controlling output stage quiescent current. The amplifier includes a driving stage including first pmos and nmos transistors coupled together, and an output stage connected to the driving stage. The output stage includes second pmos and nmos transistors coupled together. The amplifier also includes a quiescent control stage connected to the driving stage and including third pmos and nmos transistors coupled together, fourth pmos coupled to third pmos and 4nmos coupled to 3nmos. A topology of the coupled third pmos and nmos transistors substantially matches a topology of the coupled first pmos and nmos transistors, and 4pmos and nmos match to 2nd pmos and nmos.

Growing community of inventors

Irvine, CA, United States of America

Jungwoo Song