Qualcomm Incorporated

Advanced Micro Devices Corporation

Shyam Sivakumar

Kevin Jia-Nong Wang

Warren Anderson

Chao Song

Debesh Bhatta

Austen John Hypher

Kevin H Wang

Shitong Zhao

An oscillator including a switched capacitor configured to generate a sawtooth or ramp voltage in response to a switched capacitor drive signal; a low pass filter (LPF) configured to filter the sawtooth or ramp voltage to generate a filtered voltage; a reference voltage generator configured to generate a reference voltage; an integrator configured to integrate a difference between the sawtooth or ramp voltage and the reference voltage to generate a frequency control signal; a voltage controlled oscillator (VCO) configured to generate a first clock based on the frequency control signal; a frequency divider configured to frequency divide the first clock to generate a second clock; and a switched capacitor driver configured to generate the switched capacitor drive signal in response to the second clock. The oscillator may also include a switched capacitor sampler to sample the sawtooth or ramp voltage, wherein the filtered voltage is based on the sampled voltage.

Resistor-capacitor oscillator (RCO) with digital calibration and quantizaton noise reduction

An apparatus is disclosed that implements frequency synthesis with accelerated locking. In an example aspect, the apparatus includes an oscillating signal source, a modulus compensator, and a frequency generator. The oscillating signal source is configured to provide a reference signal having a reference frequency. The modulus compensator is coupled to the oscillating signal source and is configured to receive the reference signal. The modulus compensator is configured to produce a compensated modulus value based on the reference frequency, a fixed oscillator frequency of a fixed-frequency oscillator signal, and a modulus value. The frequency generator is coupled to the oscillating signal source and the modulus compensator and is configured to receive the compensated modulus value. The frequency generator is configured to generate an output signal having an output frequency that is based on the reference frequency and the compensated modulus value.

Frequency synthesis with accelerated locking

An apparatus is disclosed for relocking of a locked loop. In an example aspect, the apparatus includes a locked loop, and the locked loop includes a loop and a locked-loop controller that is coupled to the loop. The loop is configured to run responsive to a run signal. The loop includes a memory state component and signal characteristic adjustment circuitry coupled to the memory state component. The signal characteristic adjustment circuitry is configured to produce an output signal having a characteristic that is based on the memory state component. The locked-loop controller is configured to receive an external power mode signal (EPMS). The locked-loop controller is also configured to generate the run signal to have an enable value at a first time when the EPMS is indicative of an external normal mode and at a second time when the EPMS is indicative of an external standby mode.

Systems and methods of relocking for locked loops

An oscillator circuit having a programmable output frequency may include a first delay section having a negative gain and a variable delay that is set by a control signal provided to the first delay section. A second delay section having a negative gain and a fixed delay may be connected in series with the first delay section. The oscillator circuit may include an output comprising the output of the second delay section having a frequency that is dependent on the delay of the first delay section and the delay of second delay section.

Variable frequency RC oscillator

A termination impedance apparatus includes a variable pull-up resistor, a variable pull-down resistor, and a small-signal calibration circuit. The variable pull-up resistor is coupled between a first power supply voltage terminal and an output terminal. The variable pull-down resistor is coupled between the output terminal and a second power supply voltage terminal. The small-signal calibration circuit is for calibrating the variable pull-up resistor and the variable pull-down resistor to achieve a desired small-signal impedance.

Growing community of inventors

Mountain View, CA, United States of America

Shyam Sivakumar