Abstract: The security of an ordinary fence can be improved by using intersecting inserts that extend between posts of the fence. The inserts can be inserted in channels that are formed by the woven wire of the fence fabric. Intersections of the inserts can be used to securely couple two intersecting inserts to each other by any suitable means such as welding, bolting, riveting, gluing, and the like. The inserts can be securely coupled to the posts either directly (for example, by using a bracket attached to a post) and/or indirectly by using, for example, a tensioning rod that is coupled to a post. The inserts can also be securely coupled to a support rail that spans the distance between two posts.

Abstract: A circuit is arranged to provide a thermal shutdown signal in response to an overtemperature condition. The thermal shutdown circuit is typically implemented in the same die as the circuitry that is to be protected. The thermal shutdown circuit provides a first current in response to a change in temperature when a VBE associated with a transistor decreases below a predetermined level. The first current is mirrored to provide a scaled current. A thermal shutdown signal is activated when the scaled current becomes greater than a reference current. The first current is increased in response to the activated thermal shutdown signal such that the thermal shutdown circuit is deactivated at a temperature that is lower than the temperature at which the circuit is activated. The thermal shutdown circuit is deactivated when the temperature of the die decreases.

Abstract: A drain-source voltage regulator in a VPTAT generator operates with a lower minimum Vdd and provides a regulated current-mirror voltage. The minimum Vdd can be expressed as Vdd_min=Vdsat_cs+Vdsat_amp+VGS_pmir. Regulation of the current-mirror voltage is achieved by using a common-gate configuration to generate a low-voltage reference. The low-voltage reference is generated inside a regulated feedback loop that includes the VPTAT generator. The current-mirror voltage, which is outside the loop, is indirectly regulated. The current-mirror voltage can be regulated within a voltage range that spans from tens of millivolts to hundreds of millivolts.

Abstract: A method and apparatus improves the accuracy of temperature measurements by sampling measurements from a remote sensor, where currents of different current densities are applied to the remote sensor in a time-interleaved fashion. The remote sensor includes at least one PN junction that produces a voltage corresponding to the applied current at each instance of time, and related to the temperature of the remote sensor. By applying time-interleaved current densities to the remote sensor, adverse effects from temperature variations during the measurement are minimized. Sequences of current biases having differing current densities in a forward order are applied to the remote sensor, followed by the same sequence being applied to the remote sensor in a reverse order. Similarly, a random or pseudo-random sequence may be employed in a forward and reverse order. The application of forward and reverse sequences is utilized to minimize errors in the temperature measurement.

Abstract: A circuit is arranged to pulse-width modulate the duty cycle of a power supply signal that is used to control the rotational speed of a fan in a temperature-controlled system. The control system includes an edge detector for monitoring a tachometer signal that is provided by the fan. The tachometer signal is monitored at a rate (e.g., one Hertz) that is substantially lower than the rotational speed of the fan. The control system also includes a timer for recording time intervals between selected edges of a monitored tachometer signal. The fan speed is determined from the recorded time intervals. The control system extends the duty cycle of the pulse-width modulated signal to ensure that the fan power remains stable over the period in which the tachometer signal is to be monitored. Maintaining fan power ensures the validity of the tachometer signal during the period that the fan power is maintained.

Abstract: A switched capacitor amplifier provides high gain and wide bandwidth using dynamic loading. Dynamic loading is used to reduce the capacitive load during a high gain phase (e.g., during a sampling phase) and to increase the capacitive loading during a high feedback factor phase (e.g., during a holding phase). The capacitive load may be provided by an external capacitive load such as a sampling capacitor of a subsequent stage or sampling device. A low feedback factor provides a high voltage gain and the lower capacitive load. A high feedback factor increases the effective bandwidth of the amplifier by compensating for a unit gain bandwidth reduction that is due to high capacitive loading.

Abstract: The present invention is directed to a buffer having dual thresholds. The buffer has an input terminal and an output terminal and comprises a current source, first through fourth transistors, a current mirror, and an output driver. The buffer uses an “analog” topology to achieve accurate buffering when the thresholds of applied signals are not centered about the mid-supply range. The buffer is useful (among other circuits) in analog and mixed circuit integrated circuits that have relatively high voltage supply levels and signals having logic thresholds that are not centered about the mid-supply level. The buffer uses feedback from the output to achieve hysteresis.

Abstract: A transient rejecting system for protecting the state of a memory is described. The transient rejecting system includes a signal transfer circuit and a charge storage circuit coupled to at least one pin of a circuit. The signal transfer circuit receives a supply signal and determines when a transient event occurs. When a transient event occurs, the charge storage circuit provides a signal to the pin of the circuit maintaining the state of the memory prior to the transient. During normal operation, the charge storage circuit is charged, and the supply signal is provided to the pin of the memory circuit. P-channel FETs are used in the signal transfer circuit and allow for low voltage operation of the transient rejecting system.

Abstract: A single stage switched capacitor programmable gain amplifier uses programmable capacitor values to adjust gain factors. The operation of the amplifier is described by a transfer function having two gain factors: (C1/C2) and (C2/C3). The gain factor of C1/C2 applies during the holding phase and the gain factor of C2/C3 applies during the sampling phase. The transfer function is equal to the product of the two gain factors: (C1/C2)×(C2/C3) such that the transfer function is equal to (C1/C3). The intermediate element C2 can be adjusted to maximize bandwidth because C2 is independent of the total transfer gain. Accordingly, the intermediate element C2 is substantially fixed from the holding phase to the following sampling phase such that the bandwidth of the programmable gain amplifier is maximized in the two phases.

Abstract: A circuit limits a current that is initially discharged from a battery through a battery protection circuit. The current may be discharged through safety circuitry that monitors voltage slew rates and/or voltage levels. The safety circuitry may shunt current to a voltage reference (such as ground) in response to detection of a voltage that exceeds selected parameters. The shunted current may undesirably cause power to be discharged from the battery that is to be charged. A resistive path from the battery to a charger input node is formed when a voltage that is sufficient for charging a battery is detected. A charging signal also is provided in response to the detection of the voltage. A second path that has substantially no resistance is formed between the detected voltage and the battery when the charging signal attains a voltage that is suitable for charging the battery.

Abstract: A circuit is arranged to limit the rate of change in fan speed control signals. The control system includes a controller that produces a nonlinear (or piecewise linear approximation of a nonlinear function) fan speed control signal. The nonlinear fan speed control signal can reduce unnecessarily large changes in the fan speed and provide a greater degree of control at higher temperatures. Linear changes in the speed of a fan often result in audible noises that are undesirably distracting. Controlling the fan by using nonlinear exponential step sizes advantageously reduces the apparent fan noise by linearly varying the amount of fan noise in approximately equal percentages between each programmed fan speed. The step sizes are nonlinear with respect to temperature change and are linear with respect to fan noise.

Abstract: A circuit is arranged control the acceleration of a fan by limiting the rate of change in fan speed control signals. The control system includes an acceleration controller that low pass filters a target fan speed control signal. The low pass filtering signal minimizes abrupt changes in the fan speed. A sudden change in the speed of the fan often results in an audible noise that is undesirably distracting. Filtering the fan speed control signal advantageously slows the rate of the fan speed changes without having to change device drivers for controlling the fan.

Abstract: A safety circuit monitors a charging signal supplied by a charging circuit for charging a battery. Damage to the battery may occur when the voltage at the input terminal of the battery rises above the safe level for the battery. A voltage drop across a coupling circuit is used to generate an activation signal. The activation signal causes a power amplifier to lower the voltage of the charging signal before the charging signal can drive the inductances associated with the battery input terminal and leads to the point where damage to the battery may occur.

Abstract: A method and apparatus is provided for protecting voltage regulation circuits and battery cells (“cell”) when a cell is reverse-coupled to a charger. When a charger is reverse-coupled to the cell, parasitic devices in voltage regulation circuits become forward-biased. When the parasitic devices become forward-biased, the parasitic devices may carry a current that is sufficiently large to damage the voltage regulation circuits. A shunt regulator is used to detect the presence of a reverse-coupled charger (“reverse charger”) and to shunt current to a ground potential such that potentially damaging currents are prevented from flowing through the parasitic devices.

Abstract: A circuit is arranged as a class B amplifier with a rail-to-rail output swing and a small deadband. The circuit has two parallel input stages that each use an amplifier configured as a unity gain voltage follower. The output of each stage drives a high current output transistor. The output transistors are complementary transistors arranged in a common source configuration. The common source configuration operates as a complementary class B amplifier, which conducts no quiescent bias current. An offset voltage is introduced in each input stage, which creates a small deadband in the output voltage as it switches between sinking current and sourcing current. The offset voltage is selected to ensure that the output transistors are not both simultaneously activated.

Abstract: An inorganic coating material maintains the properties of high heat resistance and high electrical insulating characteristics of inorganic materials, while enhancing the degree of adhesion with respect to an object to be coated. A water-based suspension with a specific gravity in the range of 1.5 to 2.5 is obtained by using as major raw materials at least two types of metal oxide particles having heat-resistant characteristics at temperatures above 1000° C., distributing diameters of these particles in the range of 0.1 &mgr;m to 30 &mgr;m, adjusting the average value of their particle diameters to 0.2 &mgr;m to 0.

Abstract: An image sensor is disclosed that contains pixel cells that can individually provide a real-time output signal that is proportional to the instantaneous magnitude of incident radiation upon each pixel cell. The individual real-time output signals can be used to construct an electronic image. Additionally, the pixel cells of the image sensor can be used to collectively provide an accumulated real-time output signal that is proportional to the instantaneous magnitude of incident radiation upon a plurality of selected pixel cells. A propagated signal from a source such as a laser can be used to illuminate a target in an image. A reflection from the target can be detected in the accumulated real-time output signal. The range to the target can be determined using the round-trip propagation time between the sensor and the target of a propagated signal.

Abstract: The present invention is directed towards a single stage switched capacitor programmable gain amplifier. The operation of the amplifier is described by a transfer function having two gain factors: (C1/C2) and (C2/C3). The transfer function is equal to the product of the two gain factors: (C1/C2)×(C2/C3) such that the transfer function is equal to (C1/C3). The combination of the two different gain factors provides a wider range and finer step programmability of the amplifier. The amplifier does not have an idle phase, which reduces power dissipation. Additionally, the amplifier requires less switching which results in reducing the thermal noise and the switching noise produced by the amplifier.

Abstract: A circuit is used to cancel the effects of leakage in resistive circuits. A resistive circuit is used to generate a reference signal. The resistive circuit is subject to leakage at high temperatures. A matching leakage generator is selected to have leakage characteristics that are similar to the leakage characteristics of the resistive circuit. The matching leakage generator is used to generate a representative leakage current that is similar to the leakage current that is undesirably present in the resistive circuit. The representative leakage current is mirrored by a current mirror circuit. The mirrored leakage current is used to cancel the effects of leakage in the resistive circuit. Canceling the leakage current improves the accuracy of the reference signal at higher temperatures. The reference signal accuracy at high temperatures is improved because the effects of leakage current (which are greater at higher temperatures) are cancelled by the mirrored leakage current.

Abstract: A data acquisition system for sampling a temperature signal from a temperature sensor includes: a programmable current source, a buffer with a constant offset, and an analog-to-digital converter (ADC). The programmable current source selectively provides bias currents to the temperature sensor, which produces response voltages in response to the applied bias current. The buffer receives the response voltages and produces buffered response voltages that include a constant offset. The ADC is arranged to produce digital codes in response to the buffered response voltages. The digital codes are used to determine a temperature associated with the temperature sensor. The buffer isolates the temperature sensor from the ADC such that loading effects are minimized and set-up times for the conversion are minimized.