St-ericsson Sa

Shaoxing Yuanfang Semiconductor Co., Ltd.

Aura Semiconductor Pvt. Ltd

St-ericsson India Pvt. Ltd.

Silicon Laboratories Inc.

St-ericsson Pvt. Ltd.

Srinath Sridharan

Ankit Seedher

Raja Prabhu J

Sanjeev Ranganathan

Ramkishore Ganti

Jeevabharathi G

Purva Choudhary

Shyam Somayajula

Lionel Cimaz

Rakesh Kumar Gupta

Nitesh Naidu

Shivam Agrawal

Sandeep Sasi

Augusto Marques

Akash Gupta

Donald A Kerth

Aria Eshraghi

Arnold J D'Souza

Bhupendra Sharma

Debasish Behera

Chandrashekar Bg

Sriharsha Vasadi

Patrick Guyard

Ahmed Emira

David Welland

Kulbhushan Thakur

Nandini Ganig Bs

An electronic block includes multiple independent Phase-Locked Loops (PLLs) and a switch matrix. Each PLL has an input path and an output path. The switch matrix is operable to concurrently connect a respective signal on the output path of each PLL to the input path of another PLL. In an embodiment, each of the respective signals on the output paths is a corresponding frequency-correction signal generated by a low-pass filter (LPF) in the corresponding PLL. In an embodiment, each PLL includes a frequency-correction signal combiner to combine the frequency-correction signals received from any of the other PLLs with its own frequency-correction signal to form a combined frequency-correction signal. The combined frequency-correction signal is provided to a controlled oscillator in the PLL to generate an output clock of the PLL based on the combined frequency-correction signal. The frequency-correction signals may be analog or digital signals.

Inter-PLL communication in a multi-PLL environment

Clock generation circuit generating multiple divided signals satisfying respective desired offsets. A phase locked loop (PLL) is used to generate a PLL output having a frequency which is a desired multiple of that of a reference clock. The circuit divides the PLL output by a corresponding divisor to generate a corresponding divided signal, wherein each divided signal is offset from a common reference by at least an associated desired time offset. The common reference is timed with respect to the reference clock when the reference clock is available and with respect to a time reference signal otherwise. This arrangement is extended to use the internal time reference signal even for the cases where the reference clock is present by blocking the reference clock while the output systems across PLLs are aligned using the internal time reference signal to ensure desired offsets across different PLLs with a small uncertainty.

Generating divided signals from phase-locked loop (PLL) output when reference clock is unavailable

A phase-locked loop (PLL) is implemented to have another (second) PLL in place of the controlled oscillator. When a known frequency change in the frequency of the output clock is desired, in addition to changing a configuration of the PLL (first PLL), the configuration of the second PLL is also changed to cause the frequency of the output clock to change quickly. In various embodiments, the configuration of the second PLL is changed by changing the divisor of the feedback divider of the second PLL, the divisor in a pre-scaler in the second PLL, the control voltage of a VCO used in the second PLL, and any other point of user control in the second PLL.

Fast switching of output frequency of a phase locked loop (PLL)

A phase-locked loop (PLL) provided according to an aspect of the present disclosure includes a phase detector, a low-pass filter, an oscillator, an output block and a phase locking block. The oscillator generates an intermediate clock and the output block generates each of successive cycles of a feedback clock on counting a pre-determined number of cycles of the intermediate clock. The phase locking block, upon detecting the PLL being out of phase-lock, controls the operation of the output block to obtain phase-lock in the PLL within two cycles of the input clock from the time of detection of the PLL being out of phase-lock.

Obtaining lock in a phase-locked loop (PLL) upon being out of phase-lock

A phase locked loop (PLL) includes a phase detector, a first low-pass filter, an oscillator, a feedback divider and a cycle slip detector. The cycle slip detector is operable to detect at a first time instance, a cycle slip between an input clock and a feedback clock of the PLL. Upon detection of the cycle slip, the cycle slip detector is operable to increase a loop BW of the PLL. As a result, faster relocking of the PLL is achieved upon occurrence of an abrupt and large frequency difference between the input clock and the feedback clock.

Relocking a phase locked loop upon cycle slips between input and feedback clocks

A phase locked loop (PLL) includes a multiplexer (MUX), a phase detector, a filter block, an oscillator, a frequency divider, and a clock switch controller, and achieves hitless switching between a primary clock and a redundant clock. The clock switch controller, upon detecting a condition requiring switching from the primary clock to the redundant clock, is operable to restart the feedback divider synchronously with respect to the redundant clock, and derive the output of the PLL from the redundant clock. The PLL further includes a delay block to process delayed phase error signals generated by the phase detector. The PLL performs hitless clock switching in the event of input clock loss or in response to a command to switch input clocks. The PLL further includes circuitry for estimating and cancelling residual phase errors.

Hitless switching when generating an output clock derived from multiple redundant input clocks

A phase frequency detector (PFD) includes a first circuit portion and a second circuit portion. The first circuit portion receives a reference signal and activates a first error signal if the phase of the reference frequency leads the phase of a feedback signal. The second circuit portion receives the reference and activates a second error signal if the phase of the reference frequency lags the phase of the feedback signal. The first circuit portion is powered by a first power supply, and the second circuit portion is powered by a second power supply. A PLL implemented using the PFD generates a frequency output with minimized jitter.

Reducing errors due to non-linearities caused by a phase frequency detector of a phase locked loop

Systems and methods for suppressing pop-up noise in an audio signal are disclosed. The system includes a driver circuit shared by a pin interface and a complementary pin interface. A control unit is coupled to the pin interface and the complementary pin interface. To activate the pin interface, the control unit is configured to first activate the driver output at the complementary pin interface. Once the complementary pin interface achieves a preset voltage, the driver output is switched to the pin interface by the control unit. In addition, the driver circuit can be calibrated for a DC offset on the complementary pin interface by re-using calibration data calculated at the pin interface. Further, DC correction signals can be provided from a pre-biasing circuit based on the calibration data of the driver circuit.

Pop-up noise suppression in audio

A protection circuit protects a receiver from high-energy signals. In one exemplary embodiment, the protection circuit comprises a snapback transistor and a controller. The snapback transistor comprises a gate, a drain connected to an input of the receiver and a source connected to ground. The controller configured to connect the gate to a bias voltage to close the gate in a transmit mode, and to disconnect the gate from the bias voltage to open the gate in a receive mode. The snapback transistor is configured to enter into snapback responsive to a high energy signal at the drain to provide a current path from the drain to the source even when the gate is open and thus protect the receiver.

Isolation and protection circuit for a receiver in a wireless communication device

A multi-standard transceiver comprises a common balun, a controller, at least one first switch, and at least one second switch. The common balun comprises a primary coil and a secondary coil. The at least one first switch connects the primary coil of the balun to a first signal path associated with a first communication standard, or to a second signal path associated with a second communication standard responsive to a control signal provided by the controller. The at least one second switch connects the secondary coil of the balun to a first amplification path associated with the first communication standard, or to a second amplification path associated with the second communication standard responsive to a control signal provided by the controller. A common mixer is configured to provide upconverted signals to one of the signal paths depending on which communication standard has been selected.

Multi-standard transceiver architecture with common balun and mixer

Systems and methods for a low pin architecture to couple speakers with integrated circuits are disclosed herein. In an implementation, the low pin architecture facilitates in reducing the required pin interfaces to couple a low power speaker, a high power speaker, and earphone speakers with integrated circuits (ICs). For this, the high power speaker can be cross-coupled between the pin interfaces that are coupled to the low power speaker and the earphone speakers. These pin interfaces are driven by corresponding driver circuits. In said implementation, some of the driver circuits can be shared to drive multiple pin interfaces. These shared driver circuits include a combined cascode circuit having a first cascode circuit integrated with a second cascode circuit to reliably and selectively drive one or more of the pin interfaces.

Coupling of speakers with integrated circuit

Systems and methods for generation of a low jitter clock signal for wireless circuits are disclosed. In an implementation, the system includes a wireless circuit powered by a first power supply and a low jitter clock (LJC) generator powered by a second power supply. The LJC generator provides at least one clock signal to the wireless circuit. The system further includes an LJC driver circuit including a clock buffer powered by the first power supply and a receive buffer powered by the second power supply.

Generation of a low jitter clock signal

A method includes controlling a mixer gain to provide a range of selected power output levels from the mixer using a first control scheme for a low portion of the range and using a second control scheme for a high portion of the range. Using the selected mixer gain, incoming baseband signals may be upconverted in the mixer to a transmission frequency and output from the mixer at the selected power output level.

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Bengaluru, India

Srinath Sridharan