摘要:
Apparatus for compensating thermal drift of temperature sensitive circuitry in an integrated circuit by heating the temperature sensitive circuitry by applying power to a heating element in the integrated circuit, testing the temperature sensitive circuitry, and trimming a thin film resistor in accordance with the testing results. The heating element is an integrated resistor adjacent to or surrounding the temperature sensitive circuitry. The integrated circuit further includes a thin film compensating resistor which affects or determines the degree of temperature sensitivity of the temperature sensitive circuitry. As the temperature of the temperature sensitive circuitry is increased, testing apparatus is utilized to measure a temperature sensitive parameter of the temperature sensitive circuitry. Control signals indicative of the amount of required trimming of the thin film compensation resistor are produced in response to the testing to adequately compensate the thermal drift of the temperature sensitive circuitry. The control signals are utilized to control the operations of a laser which precisely trims the thin film compensating resistor by the required amount.
摘要:
A digital to analog conversion system includes a memory for storing a plurality of correction codes corresponding to corrections required to compensate for inaccuracy in output currents of a main digital to analog converter (DAC) contained in the digital to analog conversion system. A plurality of the logic inputs applied to the inputs of the main DAC are also applied to the address inputs of the memory. A trim DAC having its inputs coupled to the data outputs of the memory converts the correction code stored in the addressed location of the memory into a correction current which is utilized externally of the main DAC to modify the net amount of output current available from the main DAC to compensate for inaccuracy of the unmodified output current. An output signal from a temperature sensor is connected to a digital number which is also applied to a plurality of the address inputs. Correction codes stored in locations addressable in response to the temperature sensor have values which effect adjustment of the correction current to compensate for inaccuracy of the output current due to temperature variations. A self-calibration system and method which updates the correction codes stored in the memory are also disclosed.
摘要:
A transducer bridge amplifier system includes a first operational amplifier having positive and negative inputs connected, respectively, to first and second output nodes of the bridge. The output of the operational amplifier is connected to a third node of the transducer bridge. A transducer of the transducer bridge is connected between the second node and the third node. A second operational amplifier has its positive input connected to ground and its negative input connected to the first node. A feedback resistor is coupled between the output of the second amplifier and a negative input of the second amplifier. An output signal produced by the second operational amplifier has a linear response to transducer deviation and low sensitivity to offset voltages of the first and second operational amplifiers. In a second alternate embodiment of the invention, the second operational amplifier has its output and its negative input connected to a negative terminal of a voltage supply biasing the transducer bridge amplifier system. The second operational amplifier has its positive input connected to the first node. The current flowing into the bridge system via the first node has linear response to transducer deviation and low sensitivity to affect voltages of the first and second operational amplifiers substantially independently of any impedance connected to the first node. In a third embodiment of the invention, the second operational amplifier can be omitted. A constant current source, rather than a constant voltage source, is used to bias the transducer bridge amplifier system. The current flowing into the first node biases linear response to transducer deviation and low sensitivity to offset voltage of the first operational amplifier.
摘要:
A novel encapsulating material and method of making said material is described wherein an organopolysiloxane polymer is mixed with a polydimethyl siloxane fluid diluent, a filler of hollow glass beads and a controlled amount of sodium in the form of sodium borate. A methyl hydrogen siloxane catalyst is added to the mixture and the material cured; the total amount of sodium present in the mixture and catalyst is maintained at approximately 180 ppm.
摘要:
Means and method is disclosed for achieving a low profile optical coupling to a module comprising an optoelectronic device together with other circuitry. Maintaining the optoelectronic device parallel to the substrate on which it and the associated circuitry are mounted enables the use of standard, well known manufacturing assembly techniques while providing electrical connection to the electric ports of said optoelectronic device. Subsequent to the electrical interconnection operation, the optoelectronic device is moved, together with its connections, to a position substantially orthogonal with the mounting substrate. Optical fiber, light coupling is utilized. The low profile of the overall module package is achieved by introducing the optical fiber in a direction generally parallel with the substrate and perpendicular to the light active surface of the optic port of the optoelectronic device. The structure and method are applicable to both hybrid integrated circuit assembly technology as well as to conventional metallic lead frames for plastic encapsulation.
摘要:
This relates to a transformer coupled isolation amplifier employing multiple primary and secondary windings to separate power supply currents from signal currents. An input section includes an input amplifier, a flyback modulator and a first flyback demodulator. An output section includes an output amplifier and a second flyback demodulator. A power section alternately provides a voltage and a high impedance to the transformer, which voltage is coupled to the input and output amplifiers via first and second primary and first and second secondary windings respectively for the purpose of providing positive and negative power sources to the amplifiers. The input demodulator is coupled to the output demodulator by third primary and secondary windings.
摘要:
A semiconductor interface circuit and method of operation for transmitting and receiving information between a telephone set and a four wire switching system. The interface circuit includes DC current sources which may be modulated by a voice signal from the switching system. The current sources provide both DC power and the voice signal to the telephone set through a two wire cable. A high impedance amplifier amplifies the signal on the cable, which cable signal includes a DC voltage, a microphone signal from the telephone set, and a component due to the voice signal from the switching system, all three being dependent on the cable length. Cable termination resistors are optional. The signal from the switching system and the DC component of the output signal of the amplifier are multiplied by an inverting multiplier circuit. The output signal of the multiplier circuit is proportional to cable length and is utilized to cancel the amplifier output signal component which is related to the voice signal from the switching system. Thus, echo return is eliminated or minimized regardless of cable length. Differential optical coupling circuits are utilized to couple the signal from the switching system to the cable and to couple the cable signal to the switching system relatively independently of the efficiency of the light emitting diodes of the differential optical coupling circuits. A DC ring insertion signal is coupled from the switching system to an output of the interface circuit via one of the differential optical coupling circuits. Status signals from the telephone set are conducted via another of the differential optical coupling circuits. The semiconductor interface circuit is housed in a package having two optically isolated cavities therein.
摘要:
A ceramic substrate is provided with a plurality of planar conductors formed on a surface of the substrate; conductors extend substantially radially from an imaginary point on the surface of the substrate. A layer of dielectric material is formed over the major portion of each of the conductors to form a ring of dielectric material to which a ferrite toroidal core is adhesively secured. The core is precoated with an insulating material prior to adhesively being secured to the dielectric ring. A plurality of wire conductors are wire bonded at each end thereof to the exposed ends of the metal conductors on the substrate.
摘要:
Apparatus and method for compensating thermal drift of temperature sensitive circuitry in an integrated circuit by heating the temperature sensitive circuitry by applying power to a heating element in the integrated circuit, testing the temperature sensitive circuitry, and trimming a thin film resistor in accordance with the testing results. The heating element is an integrated resistor adjacent to or surrounding the temperature sensitive circuitry. The integrated circuit further includes a thin film compensation resistor which affects or determines the degree of temperature sensitivity of the temperature sensitive circuitry. As the temperature of the temperature sensitive circuitry is increased, testing apparatus is utilized to measure a temperature sensitive parameter of the temperature sensitive circuitry. Control signals indicative of the amount of required trimming of the thin film compensation resistor are produced in response to the testing to adequately compensate the thermal drift of the temperature sensitive circuitry. The control signals are utilized to control the operations of a laser which precisely trims the thin film compensating resistor by the required amount.
摘要:
A system for linearizing non-linear transducer output signals includes an analog-to-digital converter having a plurality of digital outputs. A first group of the most significant bits of the analog-to-digital converter digital outputs are coupled to address inputs of a read only memory. The remaining digital outputs of the analog-to-digital converter are coupled to a first group of inputs of a digital multiplying circuit. A first group of data outputs of the read only memory are coupled to a first group of inputs of a summing circuit and represent intersection points of a piece-wise linear approximation to a mathematical curve representing the relationship between unlinearized data produced by the analog-to-digital converter and linearized data produced by the linearizing system. A second group of the read only memory data outputs are coupled to a second group of inputs of the digital multiplying circuit and represent the slopes of straight lines extending from one intersection point toward another. The digital multiplying circuit produces a product word, a predetermined number of bits of which are algebraically summed with the first group of read only memory data outputs. Since the carry bits are connected, the multiplier output is really summed with the entire first group.