Cirel Systems Private Limited

Leela Madhav Lakkimsetti

Rinu Mathew

Prasenjit Bhowmik

Raghavendra Rao Haresamudram

Archit Papriwal

Soham Bhattacharjee

Akashdip Das

Anzal Saleem

Disclosed is an adaptive stylus receiver to adaptively determine presence of narrowband interference. The receiver comprises an analog-to-digital converter to digitize an incoming digitally modulated (DM) signal at a predetermined sampling frequency, a digital band pass filter configured to receive digitized DM signal and to generate a first set of frequencies from the digitized DM signal, and a frequency detection logic to adaptively determine presence of narrowband interference in a first set of frequencies, the frequency detection logic configured to estimate frequency components from the first set of frequencies, provide a first set of coefficients to a narrowband notch filter, binning of coefficients for frequencies below a threshold value, adaptively estimate narrowband notch filter coefficients by binning and provide estimated narrowband notch filter coefficients to the narrowband notch filter to suppress the narrow band interference from the first set of frequencies.

Adaptive stylus receiver to adaptively determine presence of narrowband interference and its suppression

A common source preamplifier for a MEMS capacitive sensor is disclosed. The preamplifier is a single-stage amplifier employing negative feedback. The preamplifier provides stable gain independent of temperature and at the same time provides effective buffering for a subsequent stage. Further, the preamplifier may be configured to provide different values of gain. Furthermore, the preamplifier has lower noise and consumes lesser area and lesser power than prior art.

Common source preamplifier for a MEMS capacitive sensor

A method for transitioning between Pulse Frequency Modulation (PFM) mode and Pulse Width Modulation (PWM) mode and vice versa, in a switching regulator is disclosed. In PFM mode, load current is estimated based on slope of waveform of the output voltage of the switching regulator. If the load current is greater than an upper threshold, then the switching regulator is set to PWM mode. In PWM mode, load current is estimated using duration of dead-time. If the duration of dead-time is higher than a pulse filter trip point, the switching regulator temporarily transitions to PFM mode. The load current is further estimated based on slope of the waveform of the output voltage and, if the load current is lower than a lower threshold, the switching regulator remains in PFM mode. If the load current is higher than the lower threshold, the switching regulator transitions back into PWM mode.

Automatic transition between PFM and PWM modes in a switching regulator

A circuit for selecting a maximum supply voltage from a first voltage source and a second voltage source is disclosed. The circuit comprises a comparator for comparing the first voltage and the second voltage. Based on the comparison, a first bias signal and a second bias signal are generated for biasing the gate terminals of a first power switch and a second power switch respectively. The first power switch and the second power switch are biased such that the maximum voltage among the first voltage and the second voltage appear at an output node.

Near zero quiescent current circuit for selecting a maximum supply voltage

A switching regulator circuit includes a gate driver circuit driving a first switch and a second switch to generate a first voltage at a first node. Further, the switching regulator includes an LC filter circuit responsive to the first voltage to generate a desired output voltage. Moreover, the switching regulator includes a regulator circuit coupled to the LC filter circuit to control the gate driver circuit. The regulator circuit accurately controls variations in trip point. The trip point is a voltage at which the second switch is switched OFF by the gate control circuit. The regulator circuit includes one of a Delay Locked Loop (DLL) and a Pulse width modulator (PWM) controller.

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Bengaluru, India

Leela Madhav Lakkimsetti