Abstract: Apparatus, specifically a circuit (100, 200), for a highly accurate, low cost temperature sensor, particularly one using silicon thermometry and which can be implemented by an application specific integrated circuit, that also possesses a high degree of linearity and a wide dynamic range. The inventive circuit advantageously utilizes either a mixed-signal approach or a digital core and provides independent adjustment, through two point calibration, of slope and ambient output offset values, with a zero offset adjustment advantageously accomplished through use of a digital tear. Specifically, given the inherent linearity of silicon thermometry, zero offset and desired output voltage are set, independently of each other, at a first predefined ambient calibration temperature as effectively two separate offset values, while slope (span) is set at a second predefined calibration temperature (typically a full scale temperature) different from the first temperature.

Abstract: A constant voltage circuit having excellent temperature characteristics at a wide temperature range. Temperature characteristics control means constructed by connecting a voltage dividing circuit formed by connecting fixed resistors in series to a diode in parallel is provided between a fixed resistor and a Zener diode having a positive temperature coefficient of a bridge circuit, and the output of a connection point between the fixed resistors of the temperature characteristics control means is applied to the non-inversion input terminal of a differential amplifier to correct the temperature change of the Zener diode.

Abstract: A dual current source circuit provides dual currents of the same magnitude and having coefficients of temperature compensation that are also equal but opposite. The core of the circuit is a degenerated differential pair of bipolar junction transistors wherein the base of a first transistor of the pair is connected to a bandgap voltage reference. The base of the second transistor of the pair is connected to a PTAT current source having only one of a positive or a negative coefficient of temperature compensation and a resistor which generates a voltage difference between the bases of the two transistors. This voltage difference generates dual currents, each having equal but opposite coefficients of temperature compensation. A temperature independent stable tail current is provided to the transistors and can be generated by summing the current output of a negative PTAT current source and a positive PTAT current source.

Abstract: A temperature sensor is fabricated in an integrated circuit in combination with another device such as a microprocessor using a fabrication technology that is suitable for fabricating the device. Operation of the temperature sensor is based on the bandgap physics of semiconductors using a bandgap reference circuit and an amplifier that generate two measurement voltages, a voltage that is temperature-dependent and a voltage that is temperature-independent. The temperature sensor includes a bandgap power supply circuit that supplies a power supply voltage that is very stable to drive the temperature sensor so that the temperature sensor generates an output signal that is essentially independent of the power supply voltage.

Abstract: A gain control circuit includes a first path block for a gain control voltage and a second path block for a reference voltage. The first path block includes a voltage-current linear conversion unit for outputting a current which is proportional to a gain control voltage V.sub.ctrl, and which is inversely proportional to a resistivity, and also includes a temperature characteristic compensation unit for mirroring the current output by the voltage-current linear conversion unit and outputting a current I.sub.ctrl which is proportional to the gain control voltage V.sub.ctrl and an absolute temperature, and which is inversely proportional to the resistivity. The second path block has the same construction as the first path block except that it receives a reference voltage V.sub.ref and outputs a current I.sub.ref. The current I.sub.ctrl and the current I.sub.ref are supplied to a variable- gain cell so as to produce a voltage gain A.sub.v not affected by a variation in temperature.

Abstract: A simultaneous bi-directional input/output (I/O) circuit (300) is disclosed. The I/O circuit (300) includes an output buffer (302) for driving a data bus line (306) high or low according to a data input signal (Din), and an input buffer (308) for sensing the voltage on the data bus line (306). The input buffer (308) drives a data output node (332) between logic levels by comparing the voltage on the data bus line (306) with a reference voltage (Vref1 or Vref2) that is determined by the data input signal (Din). To eliminate glitches at the data output node (332) caused by the reference voltages switching faster than the data bus line can be driven (306), a transition detector (314) is provided that generates a disable pulse when Din transitions between logic levels.

Abstract: In an emitter follower circuit, a bipolar transistor is connected to a resistor element. The bipolar transistor has a temperature dependent characteristic. A current source circuit is connected to the resistor element to flow a current through the resistor element such that a voltage drop by the resistor element has an opposite temperature dependent characteristic to the first temperature dependent characteristic of the bipolar transistor.

Abstract: A temperature sensing circuit suitable for integration with a power semiconductor device (MOSFET/IGBT) includes temperature-sensing p-n diode means (D1, D2, etc . . . ) integrated together with first and second IGFETs (M1 and M2). A current path through the temperature-sensing p-n diode means (D1, D2, etc . . . ) provides a voltage drop (Vf) having a negative temperature coefficient. The IGFETs (M1 and M2) are coupled in separate current paths from each other so as to have separate gate-to-source voltage signals (Vgs1 and Vgs2) between their source and gate electrodes (s and g). The gate-to-source voltage (Vgs1) of the first IGFET (M1) has a negative temperature coefficient of greater magnitude than the temperature coefficient (if any) of the gate-to-source voltage (Vgs2) of the second IGFET (M2). One of the source and gate electrodes (s or g) of the first IGFET (M1) is coupled to the p-n diode means (D1, D2, etc . . .

Abstract: A semiconductor device of the present invention includes a comparator including a detection side circuit to which a detection voltage is supplied and a reference side circuit to which a reference voltage is supplied. A detection element for obtaining the detection voltage is provided inside the semiconductor device, and a reference element for obtaining the reference voltage is provided outside the semiconductor device. At least one of the detection side circuit and the reference side circuit includes a temperature dependent adjustment element for reducing a difference between a temperature characteristic of the detection voltage and a temperature characteristic of the reference voltage.

Abstract: A timing circuit, for use in an integrated circuit, generates relatively long time periods. The electrical properties (for example the resistance) of a pair of matched components are measured while heat is supplied to one of the components. When the values of the thermally dependent properties of the components differ by a certain amount, the timed period is over. The pair of matched components are located within thermally insulating structures within the IC.

Abstract: A voltage reference generator (200) generates a temperature compensated voltage at an output (202). The voltage reference generator includes a first transistor (204) and a second transistor (206) series connected between a supply voltage and the output. The first transistor and the second transistor establishing the temperature compensated voltage in response to a bias current (I.sub.BIAS) and a first bias voltage and a second bias voltage. The voltage reference generator further includes a current source (208) coupled to the first transistor and the second transistor to establish the bias current in the first transistor and the second transistor. The current source produces the first bias voltage and the second bias voltage.

Abstract: In a temperature measuring circuit suitable for implementation on an integrated circuit (IC) a plurality, M, nominally unit value current sources are individually and collectively applied to a sensor such as a diode or transistor. The resulting individual V.sub.BE voltages are measured and used to form an average, V.sub.BE(AVG), of the individual voltages. The difference .DELTA.V.sub.BE between the voltage, V.sub.BE(TOT), resulting from application of all M current sources and V.sub.BE(AVG) is used to solve for temperature in a relationship that is independent of the current values used. An error-corrected version of a sigma-delta analog-to-digital converter (ADC) is used to convert the analog measurements into digital signals representative of temperature.

Abstract: An integrated circuit has circuitry formed by a fabrication process. The circuitry has an electrical characteristic that is different from a predetermined value due to variations in the fabrication process. The electrical characteristic is responsive to a level of a current, and a current source of the integrated circuit is configured to be selectably enabled to adjust the level of the current to move the electrical characteristic closer to the predetermined value.

Abstract: A logic circuit for providing hysteresis in the sensing of the temperature of an integrated circuit includes two voltage comparators and a D-type flip-flop. Each of the comparators compares a reference voltage and a respective one of two voltage signals which represent and vary in respective relations to the temperature of the integrated circuit. The resulting binary output signals of the comparators are asserted and de-asserted at different approximate temperatures, i.e., with one being higher and the other being lower with respect to one another. One comparator output signal serves as both the input data signal and output clear control signal for the flip-flop while the other serves as the clock signal. Accordingly, the output signal of the flip-flop is asserted during a time which follows an increase in the measured temperature above the higher approximate temperature value and precedes a decrease in the measured temperature below the lower approximate temperature value.

Abstract: A compensation circuit adapted to receive an input signal for a circuit element to be compensated. The input signal is used as an address to a memory at which a compensated signal is stored. The stored compensated signal is output to the circuit element as the compensated signal therefor. In a specific implementation, the command input is received by a shift register. The shift register converts a serial input to a parallel output. The parallel output of the shift register is combined with the output of a temperature sensor to provide an address for the memory. The command input data includes an address to the particular circuit element to be compensated. The temperature data is used to select a particular page of memory and the remainder of the command input data is used to select data from that page for output as the compensated signal for the selected element. In the illustrative embodiment, the components compensated are automatic gain control amplifiers.

Abstract: A current sensing circuit which provides for accurate in-line current sensing with extremely low insertion loss. A low valued resistor (e.g., 0.005 ohms) is connected in series with the source and load of the current to be measured. An analog-to-digital converter (ADC) is used to measure the resulting voltage generated across the resistor. In order to minimize inaccuracies due to voltage offsets introduced by the measurement circuitry when measuring the low voltages generated across such a low resistance, the ADC is "chopped," thereby causing self cancellation of any such offset voltages. A voltage source which provides a reference voltage for the ADC has a temperature coefficient which is approximately equal in magnitude to the temperature coefficient of the resistor. Hence, for a given current through the resistor, the reported voltage as measured across the resistor remains constant over temperature.

Abstract: The present invention relates to a process control monitoring system and method. The system and method uses current comparator circuits for monitoring process changes. Process sensitive current sources are compared with weighted reference current sources in a manner that each output of the current comparators demonstrates the inequality of the current sources. By setting the weighted reference current sources properly, the outputs of the current comparators may be used to locate the process corner of the fabricated integrated circuit.

Abstract: A selectable inverter circuit. An inverter circuit receives an input signal which is complemented before becoming an output signal. A pass-through circuit for setting the output signal equivalent to the input signal. An enabling circuit for providing power to the inverter circuit, in response to a selection signal. The enabling circuit also provides a charge storing circuit with a supplemental charge. The charge storing circuit releasing the supplemental charge to the inverter circuit, and so provides the inverter circuit with even more power. The enabling circuit activating the pass-through circuit and deactivating the inverter circuit in response to the first state of the selection signal. The enabling circuit deactivating the pass-through circuit and activating the inverter circuit in response to the second state of the selection signal.

Abstract: A threshold detector circuit (2) suitable for use with a nuclear event detector for sensing an ionising radiation pulse has a high tolerance to ambient temperature fluctuations. The threshold detector (2) comprises an amplifier stage (3) which includes a pair of complementary transistors (Q2, Q3) and a comparator stage (6) which includes a third transistor (Q4) and a voltage reference (7). Temperature compensation is achieved by the addition of a feedback loop (5) in the amplifier stage (3) including a fourth transistor (Q1) whose temperature coefficient is closely matched to that of the third transistor (Q4).

Abstract: An electronic gain circuit adapted to receive an input signal, an amplifier having a gain for amplifying the input signal to produce an output signal, and biasing resistors connected to the amplifier to automatically adjust the gain of the amplifier in response to fluctuations in ambient temperature such that the output signal of the amplifier responds to ambient temperature fluctuations.

Abstract: In a summing comparator (10) in which one differential input voltage received by one differential pair (18) is dependent on temperature variations, such as across a resistor (12) with a large temperature coefficient, the dependence on temperature is offset by introducing cancelling temperature dependence in the other differential pairs (14, 16).

Abstract: A voltage reference circuit includes at least a first and a second voltage supply having different operating temperature ranges. Output voltages of the two voltage supplies are compared and one of the supplies is selected to provide an optimum voltage reference.

Abstract: A receiver for providing binary signals from a transmission line to a data system is disclosed. The receiver includes a differential comparator for comparing a reference voltage to an input voltage and for providing a comparator output signal in response to the comparison. The comparator output signal indicates whether the input voltage is greater or less than the reference voltage. A first current source is coupled to the differential comparator for providing current to the differential comparator. The first current source provides substantially the same amount of current to the differential comparator whether the input voltage is greater or less than the reference voltage, and the first current source has a positive temperature coefficient so that when temperature increases the current provided by the first current source increases. A middle stage amplifies the comparator output signal to produce a middle stage output signal and compensates the middle stage output signal for variations in temperature.

Abstract: A clock control circuit is provided to control the frequency of a microprocessor clock signal and includes a clock management unit which controls the frequency of a timing signal applied to a clock generator and distribution unit, which correspondingly supplies an internal clock signal to a CPU core of the microprocessor. A thermal sensor is integrated with the semiconductor die which forms the microprocessor circuit. An output signal from the thermal sensor is provided to a primary temperature indicator unit and to an auxiliary temperature indicator unit. The primary temperature indicator unit is configured to assert a primary indicator signal when the temperature of the semiconductor die has increased above a first threshold level referred to as the primary threshold level, and the auxiliary temperature indicator unit is configured to assert an auxiliary indicator signal when the temperature of the semiconductor die exceeds yet a second threshold level referred to as the auxiliary threshold level.

Abstract: A protective circuit having enhanced and accurate thermal shutdown temperatures. The protective circuit establishes the thermal shutdown temperature within a predetermined range and provides an output signal when the thermal shutdown temperature is exceeded. The protective circuit, in one embodiment, comprises a current generator for supplying a predetermined collector current I.sub.c1, a current mirror arrangement for supplying a collector current I.sub.c2 which has a mirror response to that of the collector current I.sub.c1, a resistor arranged to have the mirror collector current I.sub.c2 flowing therethrough, and the combination of a resistor and a bipolar transistor serving as a thermal sensor. The current generator comprises at least a pair of bipolar transistors selected from one of the NPN and PNP types with each of said pair operating with different current densities. The base electrodes of the pair are interconnected by a resistor. The collector current I.sub.