National Semiconductor Corporation

Dan D'Aquino

Mehmet Aslan

Chungwai Benedict Ng

Qing Feng Ren

Eric Tam

An embodiment of the present invention is directed to a method of matching currents to a known ratio including generating a control signal from a control circuit, which includes a value that defines a configuration. The method also includes receiving the control signal at a switching circuit, detecting whether the value of the control signal has changed, and, provided the value has changed, switching a plurality of transistors from a first configuration to a second configuration. The first configuration produces a first current in a first circuit and a second circuit, and the second configuration produces a second current in a first circuit and a second circuit. The ratio of the first current and the second current are the aforementioned known ratio.

Matching for time multiplexed transistors

An embodiment of the present invention is directed to a method of matching time-multiplexed resistors to a known ratio including generating a control signal from a control circuit, which includes a value that defines a configuration. The method also includes receiving the control signal at a switching circuit, detecting whether the value of the control signal has changed, and, provided the value has changed, switching a plurality of resistors from a first configuration to a second configuration. The first configuration produces a first resistance, and the second configuration produces a second resistance. The ratio of the first resistance and the second resistance are the aforementioned known ratio.

Matching for time multiplexed resistors

A circuit for temperature sensing provides a bias current to a PN junction, and the PN junction provides a PN junction voltage in response to the bias current. Also, a parasitic resistance may be coupled in series with the PN junction. The circuit for temperature sensing is configured to determine the temperature of the PN junction based on the PN junction voltage. Further, the circuit includes registers which store &#x3b7;trim, which is based on the difference between the non-ideality of the PN junction used from a reference PN junction; &#x394;I, which is based on the difference between a reference bias current and the bias current for the part; Rtrim, which is based the parasitic resistance; and Ntrim, which includes other offsets. The registers may be set during trimming and/or calibration to provide accurate temperature sensing for the parameters employed.

Apparatus and method for calibration of a temperature sensor

A system for adjusting parameters of a temperature sensor for settling time reduction is disclosed. The system includes an input for receiving a signal for triggering an adjustment of one or more parameters associated with one or more portions of the temperature sensor. And, an adjuster that includes a current sourcing/sinking adjuster, a feedback loop current adjuster and a feedback loop resistance adjuster coupled to the input. The adjuster adjusts one or more voltages associated with one or more portions of the temperature sensor in response to a receipt of the signal for triggering an adjustment to achieve the settling time reduction.

Systems and methods for adjusting parameters of a temperature sensor for settling time reduction

A method and circuit for reducing a temperature dependent error in p-n junction based temperature measurements. The temperature-dependent error may be caused by parasitic resistance in a p-n junction and temperature dependent variation of a bias current in a temperature sensor. A difference in base-emitter voltage of a sensing transistor is employed to determine a temperature of a source device. In one embodiment, a zero Temperature Coefficient (TC) current source employing a temperature dependent variation of a current generates by an emitter-base voltage across a resistor between the emitter and the base of a junction transistor is used to counter balance a Proportional To Absolute Temperature (PTAT) current source.

Zero temperature coefficient (TC) current source for diode measurement

A circuit for temperature sensing receives a differential voltage that corresponds to the voltage across a forward-biased PN junction. The circuit for temperature sensing provides a first current to the PN junction, and subsequently provides a second current. Also, the temperature of the PN junction is determined based on the difference between the differential voltage when the first current is applied and the differential voltage when the second current is applied. Further, the circuit for temperature sensing self-biases half of the differential signal. The other half of the differential signal is level-shifted by an amount that is fixed and predetermined based on the self-biasing to provide a sub-ranging voltage. A sub-ranging analog-to-digital conversion is performed on the differential voltage in which the sub-ranging voltage is subtracted from the differential voltage during the conversion.

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San Diego, CA, United States of America

Dan D'Aquino