Abstract: The present invention covers novel approaches to the differential amplification of an input signal. Embodiments of the present invention have precise gain, swing to within micro-volts (?V) of ground, and have high CMRR without the need for precision resistors or tuned potentiometers. Embodiments of the present invention are particularly suited for the amplification of an instrumentation signal for delivery to an analog-to-digital converter. Examples of such signals include the product of a strain-gauge front end, a temperature sensor front end, and certain devices for bioelectronics detection.

Abstract: A temperature sensor circuit generates an output voltage that is linearly proportional to temperature over a desired temperature range with a desired offset voltage. The temperature sensor includes two Proportional To Absolute Temperature (PTAT) current sources that generate PTAT currents and two transistors which conduct the PTAT currents with different current densities to establish a basic voltage PTAT across a resistor. An offset resistor coupled between the bases of the two transistors and a circuit node, shifts the basic PTAT voltage by an offset voltage. A first gain circuit couples to the collector of the first transistor and the offset resistor and generates a servo current (i.e., a current that tends to move the circuit to the desired state by correcting an error) to servo the base of the first transistor when there is a difference between the first transistor's collector current and the PTAT current.

Abstract: A current regulator includes a regulation stage and a start-up stage. The regulation stage has a base bus and an output transistor having a base coupled to the base bus for generating a regulated current. The regulation stage also includes a current maintaining transistor coupled to the base bus for inducing and maintaining an operating current in the base bus in response to a start-up current first being induced in the base bus. The start-up stage includes a start-up transistor coupled to the base bus for inducing the start-up current in the base bus before the current maintaining transistor is turned on. The start-up transistor is turned off by the regulation stage after the current maintaining transistor is maintaining the operating current in the base bus.