Semiconductor Components Industries, LLC

Catalyst Semiconductor, Inc.

Cornel D Stanescu

Radu H Iacob

Adrian Macarie Tache

Razvan Puscasu

Adam Peter Cosmin

Horia Profeta

Sabin A Eftimie

Gerald William Steele

Marian Badila

Laurentiu O Creosteanu

Pavel Brinzoi

Andreea Creosteanu

Cristian Marian Dinca

Adrian Constantin Veselu

A high-voltage chopper-stabilized amplifier can include two paths to compensate for non-ideal electrical parameters. A first path, leading to a primary input of the amplifier, may include a first mux interface circuit to limit voltages at the primary input of the amplifier. A second path, leading to an auxiliary input of the amplifier, may include a chopper amplifier circuit. Despite the first mux interface circuit, a slew condition on the first path may excite a current in the second path that can negatively affect the signal source. Accordingly, the disclosed amplifier further includes a second mux interface circuit that can decouple the second path while a slew condition. The second mux interface circuit is driven by a window floating comparator, which is supplied according to the voltages on primary input. A settling enhancer circuit keeps, during slew condition, certain nodes on the second path at a reference voltage.

Chopper-stabilized amplifier

A differential operational transconductance amplifier, or DOTA, intended to be used in zero-drift precision operational amplifiers as chopper amplifier stage is disclosed. The DOTA is configured to function with a low-voltage power supply and to have good performance based on circuitry configured to provide a constant gain over a range of common-mode voltages, or VCM. The DOTA further includes bias circuitry configured to respond to the common mode voltage in order to prevent large currents, which can result from the constant gain circuitry, from negatively affecting performance. The DOTA further includes current sources that are configured to prevent temperature variations from negatively affecting performance. The DOTA further includes VCM-driven bias voltages used to optimize the operating point of the differential output stage. The DOTA uses input and input replica transistors having medium threshold voltage, which results in capability to operate at low supply voltages.

Differential operational transconductance amplifier for chopper-stabilized amplification

An instrumentation amplifier with an electronically adjustable gain is disclosed. The gain is adjusted by electronically controlling a resistance coupled to a feedback portion of the instrumentation amplifier. The resistance is adjusted by switches controlled by resistor-control signals references to a common mode voltage appearing at the input of the instrumentation amplifier. Accordingly, the instrumentation amplifier is capable of accommodating a high voltage range of common mode voltages while still providing controllable gain.

Gain-control circuit and method for instrumentation amplifiers

A chopper-stabilized amplifier that includes an analog driven level shifter is disclosed. The analog driven level shifter changes the levels of a pair of complementary clock signals according to a level associated with an input signal to the chopper-stabilized amplifier. The level shifted complementary clock signals are used to control switching devices used for chopping input signals of various voltages. The chopper-stabilized amplifier also includes symmetrical passive RC notch filters having two cut-off frequencies to reduce ripple noise from the chopping.

Chopper-stabilized amplifier with analog-driven level shifter

A method for adjusting common mode rejection ratio (CMRR) and gain error of a current sense (CS) amplifier, comprising: measuring a first referred to input (RTI) offset voltage while presenting a given common mode (CM) input voltage; adding a first trim resistor of a plurality of selectable trim resistors within an adjustable feedback resistor chain to a feedback electrical path; measuring a second RTI offset voltage while presenting the given CM input voltage; estimating, based upon the first and second RTI offset voltages, a third RTI offset voltage value that would result by adding a second trim resistor of the plurality of selectable trim resistors to the feedback electrical path; using the first, second and third RTI offset voltage values to identify the combination of selectable trim resistors that achieves an RTI offset voltage closest to zero volts; and adding the identified selectable trim resistors to the feedback electrical path.

Trimming method for current sense amplifiers

A low-dropout (LDO) regulator includes a voltage reference circuit to provide a reference voltage, a pass device including an input terminal coupled to a voltage input, an output terminal to provide an output voltage and a control terminal, and an error amplifier including a first amplifier input for receiving the reference voltage, a second amplifier input, an amplifier output coupled to the control terminal of the pass device. Additionally, the LDO regulator includes a feedback circuit including a feedback input coupled to the output terminal of the pass device and a feedback output coupled to the second amplifier input to provide a feedback signal. The LDO regulator further includes a control circuit including a non-volatile memory to store configuration data to control operation of the voltage reference circuit, the pass device, the error amplifier, and the feedback circuit to produce the output voltage.

Programmable low-dropout regulator and methods therefor

In one embodiment a chopper-stabilized amplifier may be formed to include a symmetrical passive RC notch filter having two cut-off frequencies. In an embodiment, the chopper stabilized amplifier may use only two clock signals to control the chopping operations.

Chopper-stabilized amplifier and method therefor

In an embodiment, a low-dropout (LDO) regulator includes at least one of a programmable voltage reference and a programmable frequency compensation circuit and is configurable to produce an output voltage. The programmable voltage reference includes a floating-gate transistor coupled to a reference output and configurable for providing a reference voltage to an input of an error amplifier. The programmable frequency compensation circuit is responsive to a programmable current reference circuit that includes at least one floating-gate transistor that is configurable to adjust a frequency compensation parameter. A control circuit is provided to selectively program floating gates of the floating gate transistors to adjust the output voltage and/or to adjust a frequency component of the output voltage.

Floating-gate programmable low-dropout regulator and method therefor

A digital potentiometer is disclosed that includes first, second, and third signal terminals. A chain of series-connected impedance elements with multiple tap points is connected between the first and second signal terminals. A plurality of first switching devices are each connected to a respective one of the multiple tap points and to an internal wiper node. A configurable output stage is connected between the internal wiper node and the third signal terminal. The configurable output stage includes a buffer and a second switching device. The second switching device is operable to bypass the buffer. A switching circuit controls switching of the first switching devices. The switching circuit includes a Gray-code counter, a Gray-code decoder, and a make-before-break circuit that controls the timing of the switching of the wiper switches.

Digital potentiometer including output buffer

A digital potentiometer, configurable and programmable using nonvolatile memory is disclosed. A unity-gain configured, rail-to-rail operational amplifier, used as voltage follower of buffer, can be inserted, by programming, between an internal wiper terminal and an output terminal of the digital potentiometer. This way, in certain applications, it is possible to take advantage of the low output resistance given by an analog buffer. The operational amplifier can be shutdown and bypassed by a switching device to provide a circuit behavior similar to a digital potentiometer without an output buffer. Using a dual-writing circuitry, first the complemented data, then the data itself, are written in the nonvolatile memory, improving the reliability. A Gray-code counter having a single bit changed at one time and no decode glitch is present. A make-before-break circuitry gives a short overlap conduction time for any adjacent pair of switches; one being turned-off while the other is turned-on. The resistor array is of high resistivity poly-type, with increased width and number of contacts, providing additional protection in short-circuited operation when the buffer is removed. The switches connected close to resistor array terminals are designed using ESD-proof rules.

Buffered configurable nonvolatile programmable digital potentiometer

A low dropout voltage regulator circuit with non-Miller frequency compensation is provided. The circuit includes an input voltage terminal; an output voltage terminal; an error amplifier having a first input coupled to a reference voltage; a voltage follower coupled to an output of the error amplifier; a pass device; and a feedback network. An input terminal of the pass device is coupled to the input voltage terminal. A control terminal of the pass device is coupled to an output of the voltage follower. An output terminal of the pass device is the output voltage terminal. The feedback network includes two resistors in series between the output voltage terminal and ground. A node between the resistors is coupled to a second input of the error amplifier. A frequency compensation capacitor also is coupled between the output voltage terminal and the node.

Low dropout voltage regulator with non-miller frequency compensation

A low dropout voltage regulator with non-Miller frequency compensation is provided. The LDO circuit has two wide-band, low-power cascaded operational transconductance amplifiers (OTAs): an error amplifier and a unity-gain-configured voltage follower. The unity-gain-configured voltage follower drives a gate of a power PMOS path transistor with a high parasitic gate capacitance. The wide-band, low-power OTAs enable the use of a single, low-value load capacitor with a low equivalent series resistance (ESR). A frequency compensation capacitor is connected in parallel with the upper resistor of a feedback network, which introduces a zero-pole pair that enhances the phase margin close to unity-loop-gain frequency.

Growing community of inventors

Bucharest, Romania

Cornel D Stanescu