Linear Technology Corporation

Brendan John Whelan

Robert C Dobkin

Michael B Anderson

Surapap Rayanakorn

Robert Loren Reay

Kristiaan B Lokere

J Spencer Wright

Tahir M Hasoon

Michael Brian Anderson

A current sensing circuit may include a shunt resistance through which current to be sensed travels. A first and a second differential amplifier may each provide an amplified output of the voltage across the shunt resistance. A switching system may deliver a current sensing signal output based on the amplified output of the first differential amplifier when the common mode voltage across the shunt resistance is low and based on the amplified output of the second differential amplifier when the common mode voltage across the shunt resistance is high. The first differential amplifier may provide its lowest output DC offset voltage when the common mode voltage is low, while the second differential amplifier may provide its lowest output DC offset voltage when the common mode voltage is high. The first and second differential amplifiers may both have a low common mode voltage rejection ratio, such as a ratio of less than 40 db at the switching frequency of switches that control the current that is sensed.

Accurate current sensing in H-bridge applications without amplifier having high common mode rejection ratio

A testing procedure may determine whether a monolithic voltage reference device meets a temperature drift specification. A first non-room temperature output voltage of the monolithic voltage reference device may be measured while the monolithic voltage reference device is at a first non-room temperature which is substantially different than room temperature. First non-room temperature information may be stored in a memory within the monolithic voltage reference device which is a function of the first non-room temperature output voltage. A second non-room temperature output voltage of the monolithic voltage reference device may be measured while the monolithic voltage reference device is at a second non-room temperature which is substantially different than the room temperature and the first non-room temperature. Second non-room temperature information may be stored in the memory without destroying the first non-room temperature information which is a function of the second non-room temperature output voltage. A determination may be made whether the monolithic voltage reference device meets the temperature drift specification based on a computation that is a function of both the first non-room temperature information and the second non-room temperature information.

Monolithic voltage reference device with internal, multi-temperature drift data and related testing procedures

A first and a second group of individual transistors in a voltage reference may collectively function as a first and a second composite transistor with a first and a second emitter area equal to the combined areas of the emitters of the first and the second groups of individual transistors, respectively. The second emitter area may be larger than the first emitter area. The stability of the reference voltage may depend upon the stability of the ratio between the first emitter area and the second emitter area. The first group of individual transistors may not be at the center of an arrangement of the second group of individual transistors. The constant reference voltage may vary due to thermal hysteresis by less than 200 parts per million over a 40 degree centigrade temperature range.

Low thermal hysteresis bandgap voltage reference

A class AB folded-cascode amplifier having improved gain-bandwidth product, comprises a differential input circuit including a differential transistor pair coupled to a source of tail current and responsive to a differential input signal for conducting a first current, a cascode circuit coupled to the differential input circuit for supplying a second current thereto, and a class AB output stage. A compensation circuit is configured for feeding back mutually complementary compensation signals from an output node to the differential input circuit. Another compensation circuit is configured for feeding back a signal from the output of the output stage to the input of the output stage.

Class AB folded-cascode amplifier having cascode compensation

A class AB folded-cascode amplifier having improved gain-bandwidth product, comprises a differential input circuit including a differential transistor pair coupled to a source of tail current and responsive to a differential input signal for conducting a first current, a cascode circuit coupled to the differential input circuit for supplying a second current thereto, and a class AB output stage. A compensation circuit is configured for feeding back mutually complementary compensation signals from an output node to the differential input circuit.

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Discovery Bay, CA, United States of America

Brendan John Whelan