Analog Devices,inc.

Apple Inc.

Evaldo M Miranda, Jr

Erhan Ozalevli

Arthur Joseph Kalb

A Paul Brokaw

Jonathan Mark Audy

Behzad Mohtashemi

Parin Patel

Mohammad Jafar Navabi-Shirazi

Jamie L Langlinais

John Anthony Cleary

Mark A Yoshimoto

David Thomson

Michael G Tuthill

Rajarshi Paul

Michael P Daly

Anthonius Bakker

John Blake

Damon Lee

Elizabeth A Lillis

Embodiments relate to an amplifier circuit. The amplifier circuit includes multiple transistors. Each transistor is configured to receive an input signal and output an amplified signal. The amplifier circuit additionally includes a set of input chopper circuits and a set of output chopper circuits. Each output chopper circuit corresponds to one input chopper of the set of input choppers. Each input chopper circuit and its corresponding output chopper are controlled by one or more control signals from a set of control signals. Each input chopper circuit is configured to selectively connect each transistor of a transistor pair to a first input terminal or a second input terminal based on a value of the one or more control signals. Moreover, each output chopper circuit is configured to selectively connect each transistor of the transistor pair to a first output terminal or a second output terminal based on the value of the one or more control signals.

Amplifier circuit with distributed dynamic chopping

Embodiments relate to sensing a current provided by a power supply circuit. The current sensing circuit includes a sense transistor for sensing the current provided by a main transistor, a driver for controlling a bias provided to the sense transistor and the main transistor, and a sense resistor for converting the sensed current to a voltage value. Moreover, the current sensing circuit includes a controller that modifies at least one of: (a) a resistance of the main transistor by adjusting the bias voltage provided by the driver, (b) a gain ratio between a load current and a sensing current by adjusting a number of individual devices that are active in the sense transistor, and (c) a resistance of the sense resistor.

Dynamically controlled auto-ranging current sense circuit

LED backlight circuits for a display and methods for operating the circuits are disclosed. The LED backlight circuit includes a set of drivers and a set of LED strings. A driver can control a light output level of the LED strings. The LED strings can be controlled by a mixed-mode LED driver that utilizes a PWM control signal over a first range of light output levels and an analog control signal over a second range of light output levels. Clock signals used for PWM control and for frequency-to-current or frequency-to-voltage conversion for analog control can both be generated from a phase locked loop (PLL).

Frequency-to-current/voltage converter based mixed-mode LED drivers

A multi-phase switch mode, voltage regulator has a transient mode portion in which a phase control output is coupled to one or more control inputs of one or more switch circuits that conduct inductor current through one or more transient phase inductors, from amongst a number of phase inductors. A slew mode control circuit detects a high slope and then a low slope in the feedback voltage and, in between detection of the high slope and the low slope, pulses the phase control output of the transient mode portion so that the switch circuit that conducts transient phase inductor current adds power to, or sinks power from, the power supply output. Other embodiments are also described.

Slew mode control of transient phase based on output voltage slope of multiphase DC-DC power converter

In an example, a system and method are disclosed for providing a single control law that is operable to regulate both small-signal, steady-state operation, and large-signal transients of a switching regulator. The control law is based on detecting a zero-crossing of capacitor current, and projecting in advance a turning point for either ramping up or ramping down capacitor voltage at a target voltage. Certain embodiments may realize the control function in high-speed analog components, although certain other embodiments may implement the same or a similar control law in a digital controller.

Auto-tuning switching regulator

Electrical networks are formed to produce an approximation of at least one desired performance characteristic, based on the recognition that fabrication variations introduce slight differences in electronic sub-networks which were intended to be identical. These fabrication differences are turned to an advantage by providing a pool of sub-networks, and then selectively connecting particular combinations of these sub-networks to implement networks that approximate the desired performance characteristics. The sub-networks are of like kind (e.g., resistors) and have a like measure.

Electrical networks and methods of forming the same

Apparatus and methods for forming electrical networks that approximate desired performance characteristics

A high-side current sense circuit comprises a sense resistance Rconnected in series with a signal having an associated current to be measured I, which develops voltages Vand Von either side of R. A differential gain stage powered by supply voltages VCC and VEE produces an output voltage which varies with the difference between its input signals. To keep the common mode portion of the input signal between voltages VCC and VEE, a voltage modification circuit subtracts or adds a common mode voltage to or from Vand Vto produce modified voltages V' and V&#x2032;, which are coupled to the gain stage inputs. The voltage modification circuit is arranged to ensure that VEE&#x2266;V&#x2032; and V&#x2032;&#x2266;VCC.

High-side current sense circuit with common-mode voltage reduction

A switched current temperature sensing circuit comprises a BJT arranged to conduct a forced emitter current Iof the form I+(I/&#x3b2;), such that the base current is given by I/&#x3b2; and the collector current is given by I+(I/&#x3b2;)&#x2212;(I/&#x3b2;)=I. Base current I/&#x3b2; is mirrored to the emitter, and a current source provides current I, which is switched between at least a first value I and a second value N*I such that the BJT's base-emitter voltage has a first value Vwhen I=I and a second value Vwhen I=N*I, such that:&#x394;V=V&#x2212;V=()(ln N),where nis the BJT's emission coefficient, k is Boltzmann's constant, T is absolute temperature, and q is the electron charge.

Switched current temperature sensing circuit and method to correct errors due to beta and series resistance

A voltage source includes first and second pn junctions which conduct the outputs of respective current sources to establish respective base-emitter voltages Vand Vat respective nodes; Vand Vcan each be generated with a current I or a current N*I. An amplifier Ahas its non-inverting input connected to the second node and its inverting input connected to the first node through an input capacitor; a feedback capacitor is connected between the inverting input and a third node. Switches are connected between A's inverting input and A's output, between the third node and A's output, and between the third node and a circuit common point. A control circuit operates the switches and current sources during first and second operating phases to selectively produce a temperature independent output voltage or a temperature dependent output voltage.

Voltage source circuit with selectable temperature independent and temperature dependent voltage outputs

A switched current temperature sensing circuit () comprises a measuring transistor (Q) which is located remotely of a measuring circuit () which applies three excitation currents (I,I,I) of different values to the measuring transistor (Q) in a predetermined current sequence along lines (). Resulting base/emitter voltages from the measuring transistor (Q) are applied to the measuring circuit () along the same two lines () as the excitation currents are applied to the measuring transistor (Q). Voltage differences &#x394;Vof successive base/emitter voltages resulting from the excitation currents are integrated in an integrating circuit () of the measuring circuit () to provide an output voltage indicative of the temperature of the measuring transistor (Q). By virtue of the fact that the measuring transistor (Q) is excited by excitation currents of three different values, the effect of current path series resistance in the lines () on the output voltage indicative of temperature is eliminated. The predetermined current sequence in which the excitation currents are applied to the measuring transistor (Q) is selected to minimize the voltages in the integrating circuit () during integration of the voltage differences &#x394;V.

Method and a measuring circuit for determining temperature from a PN junction temperature sensor, and a temperature sensing circuit comprising the measuring circuit and a PN junction

A decoupled switched current temperature circuit with compounded .DELTA.V.sub.be includes an amplifier having an inverting input with corresponding non-inverting output and a non-inverting input with a corresponding inverting output; a PN junction connected to the non-inverting input through a first input capacitor and a voltage reference circuit is connected to the inverting input through a second input capacitor; a current supply includes a low current source and a high current source; a switching device applies the high current source to the PN junction and applies the low current source to the PN junction for providing the .DELTA.V.sub.be of the PN junction to the first capacitor; a first feedback capacitor is interconnected between the inverting output and the non-inverting input and a second feedback capacitor is interconnected between the non-inverting output and inverting input of the amplifier to define the gain on each of the inputs to produce a differential voltage across the outputs representative of the temperature of the PN junction; first and second reset switching devices discharge the first and second feedback capacitors, respectively, and a multi-phase switched device alternately interchanges the connection of the first and second input capacitors with the amplifier inputs for compounding the single .DELTA.V.sub.be .

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Saratoga, CA, United States of America

Evaldo M Miranda, Jr