Qualcomm Incorporated

Dhaval Shah

Burt Lee Price

Yeshwant Nagaraj Kolla

Jonathan H Liu

Jin Liang

Yu Sun

Hans Lee Yeager

Ajay Janardanan

A system is disclosed. The system includes a first stage configured to receive Vand V, the first stage including an input transistor pair, wherein the input voltage is coupled to the input transistor pair, the input transistor pair is coupled to ground, and the input transistor pair includes at a common drain a high-gain node having a voltage V. The system further include a second stage coupled to the high-gain node and configured to generate Vbased on a difference between Vand V, the second stage comprising a resistor and an inverter transistor pair, wherein the gates of the inverter transistor pair are coupled to the high-gain node of the first stage and the resistor couples the high-gain node of first stage to a common drain of the inverter transistor pair and is configured to provide and/or draw current to and/or from the high-gain node of first stage.

Comparator architecture and related methods

Aspects for sensing total current of distributed load circuits independently of a spatial profile of the total current using distributed voltage averaging are disclosed. In one aspect, a current sense circuit is configured to sense total current of a distributed load circuit independently of where current is distributed. The current sense circuit includes distributed voltage averaging circuits configured to determine average voltages of the distributed load circuit based on voltages sensed at multiple resistive paths corresponding to a distribution network configured to provide voltage to the distributed load circuit. An amplifier includes an output node having an output voltage that is proportional to total current flowing in the distributed load circuit. The current sense circuit allows for sensing total current independent of where the current flows, providing more accurate current sensing compared to sensing current in one area of the distributed load circuit.

Sensing total current of distributed load circuits independent of current distribution using distributed voltage averaging

In a particular implementation, an apparatus to stabilize a supply voltage includes a first current source, a second current source, and a control circuit. The first current source is responsive to a detection signal and has an output coupled to a voltage regulator circuit via an output node. The second current source is also coupled to the output node. The control circuit includes an input responsive to the detection signal and an output coupled to the second current source. The control circuit is configured to enable the second current source based on a delayed version of the detection signal.

Device and method to stabilize a supply voltage

Systems and methods relate to extending life of a low-dropout (LDO) voltage regulator. A differential amplifier of the LDO voltage regulator includes switches that can be selectively turned on or off. When the LDO voltage regulator is bypassed or turned off (or not active), a first switch is turned on to selectively couple gates of a first input transistor and a second input transistor of the differential amplifier, to maintain the gates at a same voltage. The first switch is turned off to decouple the gates when the LDO voltage regulator is active. Further, a second switch can be turned on or off to selectively couple or decouple, respectively, the gate of the second input transistor to an output voltage of the LDO voltage regulator, based on whether the LDO voltage regulator is active or not active, respectively.

LDO life extension circuitry

Automatically calibrating operational amplifier (op-amp) systems for mitigating effects of offset voltages are disclosed. In one aspect, an automatically calibrating op-amp system is provided that employs an analog calibration signal corresponding to a calibration mode to compensate an output voltage signal of an op-amp corresponding to an amplify mode. An automatic calibration circuit is included that employs a successive approximation register (SAR) controller configured to successively generate digital values based on the output voltage signal of the op-amp in response to a mode signal indicating the calibration mode. The automatic calibration circuit includes a digital-to-analog converter (DAC) configured to convert each successive digital value into the analog calibration signal in response to the mode signal indicating the calibration mode. The analog calibration signal is provided to an auxiliary differential input of the op-amp to compensate for the composite offset voltage in the amplify mode.

Automatically calibrating operational amplifier (op-amp) systems for mitigating effects of offset voltages

Aspects of generating asynchronous clock signals for successive approximation register (SAR) analog to digital converters (ADCs) are disclosed. In one aspect, an asynchronous clock generator circuit is provided that is configured to receive a voltage generated by a comparator in a SAR ADC, and generate an outside-window signal in response to the voltage being outside of a voltage threshold window. The asynchronous clock generator circuit is configured to generate a trigger signal in response to the outside-window signal coinciding with the asynchronous clock signal being in an inactive state. In response to the trigger signal being in an active state for a minimum time, the asynchronous clock generator circuit is configured to generate an edge signal, and generate the asynchronous clock signal having a pulse width in response to the edge signal. The asynchronous clock generator circuit adaptively generates the asynchronous clock signal according to timing of each comparison.

Generating asynchronous clock signals for successive approximation register (SAR) analog to digital converters (ADCs)

Switched power control circuits for controlling the rate of providing voltages to powered circuits are disclosed. In one aspect, a switched power control circuit is provided that is configured to control activation of a headswitch circuit such that the headswitch circuit gradually provides a supply voltage to a powered circuit rather than providing full supply voltage in a substantially instantaneous manner. To gradually ramp up an output voltage, the headswitch circuit is configured to provide the output voltage to the powered circuit in response to a control signal received on a control input. The control signal is generated by a control circuit in response to an enable signal. To prevent the headswitch circuit from providing the full supply voltage to the powered circuit instantaneously, a current sink circuit is configured to control a ramping rate of the output voltage generated by the headswitch circuit.

Switched power control circuits for controlling the rate of providing voltages to powered circuits, and related systems and methods

Distributed voltage network circuits employing voltage averaging, and related systems and methods are disclosed. In one aspect, because voltage in one area of a distributed load circuit may vary from voltage in a second area, a distributed voltage network circuit is configured to tap voltages from multiple areas to calculate average voltage in the distributed load circuit. The distributed voltage network circuit includes a voltage distribution source component having source nodes. Voltage is distributed from each source node to a corresponding voltage load node via resistive interconnects. Voltage tap nodes access voltage from each corresponding voltage load node. Each voltage tap node is coupled to an input node of a corresponding resistive element in voltage averaging circuit. An output node of each resistive element is coupled to a voltage output node of the voltage averaging circuit, generating the average voltage of the distributed load circuit on the voltage output node.

Distributed voltage network circuits employing voltage averaging, and related systems and methods

Phase-dependent operational amplifiers ('op-amps') employing phase-based frequency compensation, and related systems and methods are disclosed. A phase-dependent op-amp is provided configured to provide output voltage based on inputs switched by clock signal. The op-amp employs a frequency compensation system having multiple frequency compensation circuits. The frequency compensation circuit corresponding to the clock phase is selected by selection circuit and coupled to the voltage output node. The op-amp charges each frequency compensation circuit during the clock phase to store voltage approximately equal to output voltage. When transitioning to a clock phase, output voltage of op-amp does not have to charge frequency compensation circuit. Voltage of frequency compensation circuit stored during clock phase is approximately equal to output voltage of op-amp for clock phase. The op-amp need only provide a small amount of voltage to the frequency compensation circuit to slew it to its designed voltage during instances of its clock phase.

Phase-dependent operational amplifiers employing phase-based frequency compensation, and related systems and methods

A switchable bias current biases, in an operational state, a differential amplifier with a full-slew bias current. A system on/off signal transitions from an operational state to a power-down state. The transition disables the differential amplifier and switches the switchable bias current to a reduced slew bias current. The system on/off signal transitions from the power-down state to the operational state, the differential amplifier is enabled, and the switchable bias current is delayed, by a reduced slew duration, from switching to the full-slew bias current. The enabled differential amplifier slews toward a reference voltage at a reduced slew rate caused by the reduced slew bias current. The switchable bias current, after the reduced slew duration, switches to the full-slew bias current. Optionally, a regulated pass gate is disabled in response to the system on/off signal transitioning from the operational state to the power-down state.

Method and apparatus reduced switch-on rate low dropout regulator (LDO) bias and compensation

An adaptive low dropout (LDO) regulator includes a load-based bias controller that generates a bias control signal based on the output load current, and has a differential amplifier with a bias adjustment that receives the bias control signal and responds by adjusting a bias of a transistor within the adaptive LOD regulator. Optionally, the bias control signal is generated according to a hysteresis rule. Optionally, the adaptive LOD regulator includes an adaptive load-based compensation network having a zero, the zero having a location based, at least in part, one more of an adjustable resistance or capacitance value controlled by the load-based bias controller.

Method and apparatus for load adaptive LDO bias and compensation

A transient response accelerated (TRA) low dropout (LDO) regulator has an error amplifier having a feedback input, and a reference input configured to receive a reference voltage, and an output that controls a pass gate. The pass gate output voltage is applied to the feedback input. A transient response accelerator (TRA) circuit detects a rapid voltage drop on the pass gate output and, in response, applies a pulse control that rapidly lowers the resistance of the pass gate.

Method and apparatus for LDO and distributed LDO transient response accelerator

Dual-string digital-to-analog converters (DACs), and related circuits, systems, and methods are disclosed. In embodiments disclosed herein, a primary voltage divider of the dual string-DAC is comprised of at least one adjusting circuit. The adjusting circuit is configured to maintain the ideal voltage of a selected resistor node pair across a secondary voltage divider circuit in response to a primary switch unit selecting a selected resistor node pair. In this manner, impedance isolation is not required between a primary voltage divider and the secondary voltage divider circuit of the dual-string DAC. As a result, as non-limiting examples, the area on an integrated circuit (IC) for a dual-string DAC may be decreased, power consumption of the DAC may be decreased, and/or the dual-string DAC may have increased performance by not requiring a settling time.

Dual-string digital-to-analog converters (DACs), and related circuits, systems, and methods

Methods and apparatus for a successive approximation register analog to digital converter are provided. In an example, provided is a method for digitally representing an analog input signal. A bit of the digital output signal is generated by altering a test voltage by an amount comparable to a weight afforded to the bit, comparing the altered test voltage with the analog input signal to create a comparison output, switching a two-to-one multiplexer to select the comparison output instead of a preceding shift-successive approximation register block output, storing the comparison output in a flip-flop, inhibiting clocking of the flip-flop, and outputting the comparison output from the flip-flop as the bit of the digital output signal.

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Raleigh, NC, United States of America

Dhaval Shah