Analog Devices,inc.

Evaldo M Miranda

David Thomson

A Paul Brokaw

Jonathan Mark Audy

John Anthony Cleary

Todd L Brooks

John Blake

Peter S Henry

Michelle Mahony

The present invention is connected across a sense resistor which carries a current of interest. A first pair of cross-coupled switches are connected between the sense resistor and respective input capacitors, and a second pair of cross-coupled switches are connected between the input capacitors and the inputs of an amplifier having differential inputs and outputs. Feedback capacitors are connected between each of the amplifier's outputs and inputs. A control circuit operates the cross-coupled switches in accordance with a switching cycle, during which the connections between the sense resistor and the input capacitors are interchanged, after which the connections between the input capacitors and the differential amplifier are interchanged. When so arranged, the sensed voltage is sampled on the input capacitors and transferred to the feedback capacitors to produce a differential output voltage V from the differential amplifier which is proportional to the current of interest.

Current measurement circuit

A dynamically boosted current source circuit improves the response speed of a circuit responsive to a transitioning input signal. The circuit's responsiveness varies with the magnitude of the current provided to an identified node, and a current source capable of providing nominal and boosted currents is connected to the node. A threshold detector detects the occurrence of an input signal transition prior to its detection by the responsive circuit, and triggers the current source to provide the boosted current; this improves the responsive circuit's speed by charging or discharging identified node capacitances which hinder its operation. The identified node can be an input node, an output node, or an internal node. The current source provides the boosted current for a predetermined time interval, or until the input signal crosses a second threshold, enabling response speed to be increased without a significant increase in supply current.

Dynamically boosted current source circuit

A comparison system compares a voltage which is proportional to absolute temperature S.sub.p to one which is equal to the sum of a conventional, uncorrected, bandgap cell voltage VBG and a proportional to absolute temperature voltage CT. The addition of CT to the uncorrected bandgap signal value yields a signal of the form Sp/(VBG+CT), which exhibits improved linearity over a signal of the form Sp/VBG, where VBG includes a Tln(T) term.

Ratio correction circuit and method for comparison of proportional to

A voltage divider and inverter provide a power-on-reset signal. The divider is placed between high and low power voltages, the divided voltage is the input to the inverter and the output of the inverter is the power-on-reset signal. The divider and inverter may be implemented on a single integrated circuit and accompany other, control and operational, circuitry on the integrated circuit. The divider is chosen so that the input to the inverter reaches the inverter's threshold voltage when the power voltage reaches a predetermined value.

Voltage-controlled reset for logic state initialization

An alarm based upon the voltage across a linear regulator's pass transistor and the regulator's load current alerts operational circuitry which obtains power through the regulator when the voltage across the pass transistor may be insufficient for proper voltage regulation. The alarm's trigger voltage is adjusted in response to variations in the regulator's output current.

Voltage detector with trigger based on output load currency

A low drop-out voltage regulator is compensated by providing a compensation capacitor across an output terminal of the regulator and an output lead of an input stage which compares a reference voltage and a voltage derived from a regulated output signal at the output terminal. The output from the input stage is inverted without gain before being provided to an output stage. This inversion allows Miller compensation with the compensation capacitor.

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San Jose, CA, United States of America

Evaldo M Miranda