摘要:
A fan driver circuit for powering a fan with a linear voltage may be designed using digital design techniques, resulting in a testable, accurate circuit on a smaller die size. The fan driver circuit may be configured to receive a digital control signal, which may be a sequence of numeric values, e.g. multiple-bit binary numbers, each indicative of a desired present rotational speed of the fan. The fan driver circuit may be implemented using a digital modulator, e.g. a delta-sigma modulator, with a simple low-pass filter, e.g. an RC-filter at the output, and may use oversampling based on a system clock, to shift in-band noise to out-of-band frequencies, and digital interpolation to filter out unwanted images from the upsampled digital control signal. The delta-sigma modulator may be constructed as a first-order delta-sigma modulator using an error-feedback structure to reduce die size.
摘要:
An impedance network, which includes at least one end terminal, a wiper terminal, a center impedance element, and a first plurality of impedance elements. The wiper terminal provides a tap position at a selected impedance value of the impedance network, selectable at a specified increment value. The first plurality of impedance elements is configured to reduce resistance variation during switching from one tap position to another tap position. The first plurality of impedance element is connected in series in a mirrored configuration about the center impedance element.
摘要:
An impedance network, which includes at least one end terminal, a wiper terminal, a center impedance element, and a first plurality of impedance elements. The wiper terminal provides a tap position at a selected impedance value of the impedance network, selectable at a specified increment value. The first plurality of impedance elements is configured to reduce resistance variation during switching from one tap position to another tap position. The first plurality of impedance elements is connected in series in a mirrored configuration about the center impedance element.
摘要:
A conjugate vaccine for Nontypeable Haemophilus influenzae comprising lipooligosaccharide from which esterified fatty acids have been removed conjugated to an immunogenic carrier. The vaccine is useful for prevention of otitis media and respiratory infections in mammals.
摘要:
A control circuit for controlling the rotational speed of a fan may include a memory element to store operating data corresponding to an operational profile of the fan defined by RPM (revolutions per minute) versus temperature, with the operating data comprising a respective temperature value and a respective RPM value for each respective operating point representing a change in slope of a function that corresponds to the operational profile of the fan. A processing unit may operate to receive a present temperature value, retrieve the operating data from the storage unit, and identify a pair of consecutive operating points such that the present temperature value is greater than a lower respective temperature value of the pair of consecutive operating points, and lower than a higher respective temperature value of the pair of consecutive operating points. The processing unit may calculate a desired RPM value corresponding to the present temperature value by performing linear interpolation between the pair of consecutive operating points, and output the desired RPM value to a closed-loop fan controller configured to control a rotational speed of the fan according at least to the desired RPM value.
摘要:
A fan driver circuit for powering a fan with a linear voltage may be designed using digital design techniques, resulting in a testable, accurate circuit on a smaller die size. The fan driver circuit may be configured to receive a digital control signal, which may be a sequence of numeric values, e.g. multiple-bit binary numbers, each indicative of a desired present rotational speed of the fan. The fan driver circuit may be implemented using a digital modulator, e.g. a delta-sigma modulator, with a simple low-pass filter, e.g. an RC-filter at the output, and may use oversampling based on a system clock, to shift in-band noise to out-of-band frequencies, and digital interpolation to filter out unwanted images from the upsampled digital control signal. The delta-sigma modulator may be constructed as a first-order delta-sigma modulator using an error-feedback structure to reduce die size.
摘要:
A conjugate vaccine for Neisseria meningitidis comprising lipooligosaccharide which does not contain a lacto-N-tetraose antigen from which at least one primary O-linked fatty acid has been removed conjugated to an immunogenic carrier. The vaccine is useful for prevention of meningitis and septic shock in mammals.
摘要:
A PLL response time is accelerated with a frequency detector counter. The PLL utilizes both a phase frequency detector and the frequency detector counter. Initially, the operation of the PLL is controlled by the frequency detector counter and the output of phase frequency detector does not affect the PLL system. During this period, the PLL synchronizes to an input clock frequency. After the PLL reaches a predetermined frequency range, the frequency detector counter stops working. Thereafter, the phase frequency detector controls the operation of the PLL. During this period, the PLL synchronizes to both the frequency and the phase of the input signal.
摘要:
A control circuit for controlling the rotational speed of a fan may include a memory element to store operating data corresponding to an operational profile of the fan defined by RPM (revolutions per minute) versus temperature, with the operating data comprising a respective temperature value and a respective RPM value for each respective operating point representing a change in slope of a function that corresponds to the operational profile of the fan. A processing unit may receive a present temperature value, retrieve the operating data from the storage unit, and identify a pair of consecutive operating points corresponding to the present temperature. The processing unit may calculate a desired RPM value corresponding to the present temperature value by performing linear interpolation between the pair of consecutive operating points, and provide the desired RPM value to a closed-loop fan controller to control the fan according to the desired RPM value.
摘要:
A control circuit for controlling the rotational speed of a fan may include a memory element to store operating data corresponding to an operational profile of the fan defined by RPM (revolutions per minute) versus temperature, with the operating data comprising a respective temperature value and a respective RPM value for each respective operating point representing a change in slope of a function that corresponds to the operational profile of the fan. A processing unit may receive a present temperature value, retrieve the operating data from the storage unit, and identify a pair of consecutive operating points corresponding to the present temperature. The processing unit may calculate a desired RPM value corresponding to the present temperature value by performing linear interpolation between the pair of consecutive operating points, and provide the desired RPM value to a closed-loop fan controller to control the fan according to the desired RPM value.