Standard Microsystems Corporation

Microchip Technology Inc.

Smsc Holdings Sarl

Lynn Russell Kern

James P McFarland

Scott Cameron McLeod

Chao-Ming Tsai

Joe A Marrero

Vadim A Konradi

Kenneth W Gay

Mitchell E Polonsky

Eli Kawam

A temperature sensor device has a digital interface with a first memory storing a current temperature value which can be read through the digital interface and a second memory storing a rate of temperature change value which can be read through the digital interface. Such a temperature sensor can be preferably used in a system with a cooling fan and a processor coupled with the digital interface of the temperature sensor. The processor is operable to control the cooling fan based on temperature measurement values and the rate of change in temperature retrieved from the temperature sensor through the digital interface.

Determining rate of change in temperature measurements

A system has a plurality of circuits each having an individual ground connection. The system further has a common ground connection connected with each ground connection of each circuit of the plurality of circuits via an associated isolation circuit, wherein each isolation circuit has: an NMOS transistor having a load path connecting the common ground connection with an individual ground connection of an associated circuit, and having a gate connection receiving an activation signal, and a first shunt resistor coupled in parallel with the load path.

Method and system for ground plane isolation

A power monitoring circuit and method for detecting deviations in the output of a power supply. The power monitor is configured to detect and measure two different types of deviations: transient deviations short surges or spikes in the current drawn by the device being powered and prolonged deviations over a threshold current that may be intentional, temporary increases in the output of the power supply. The power monitor collects information such as the number of each type of deviation, the duration of each deviation and the peak current describing identified deviations. This collected information can then be used, especially during the development phase, to locate the root cause of the deviation. The components of the power monitor used to detect and measure these deviations may be disabled and enabled as needed.

Circuit for measuring power violations using high side current sensing

A combination of a precision analog-to-digital converter (ADC), an analog amplifier having selectable gains and an intelligent controller to coordinate the amplifier gain selection and placement of the digital conversion results into at least one register provide for a very high resolution analog-to-digital conversion process, at a high sample rate and low power consumption. For example, a 14-bit ADC may be used with selectable gain analog amplification, e.g., &#xd7;1, &#xd7;2, &#xd7;4 and &#xd7;8, between the sampled signal and ADC input and an intelligent controller to provide a 17-bit conversion number having proper scaling of the digital sample words. The entire high resolution analog-to-digital conversion process may be automatically performed without additional control from external hardware/software.

Mixed signal automatic gain control for increased resolution

System and method for initiating rotation of a rotor in a motor. The motor may include the rotor and a plurality of pairs of electromagnets. A rotation period may be determined. One or more pairs of electromagnets of the plurality of pairs of electromagnets may be excited at a first excitation level. The excited one or more pairs of electromagnets may be determined based on the rotation period. The excitation level may be decreased, over a first period of time, to a second excitation level. The second excitation level may be a lower excitation level than the first excitation level. The excitation level may be increased, over a second period of time, to a third excitation level. The third excitation level may be a higher excitation level than the second excitation level. The rotation period may be decreased over the first and second periods of time.

System and method for inducing rotation of a rotor in a sensorless motor

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.

RPM controller using drive profiles

A motor includes a rotor and a plurality of pairs of electromagnets. The energy needed for alignment of the rotor is used to generate the first movement in forced commutation and may be combined with the initial energy to start the motor. The logic is configured to align the rotor by energizing the three coils of the motor. PWM is applied to the first coil to control current on the coils; when a maximum PWM duty cycle is reached, the coil not required to rotate the correct direction are released, thereby initiating motion in a rotor. A rotation period is determined. One or more pairs of electromagnets are excited at a first excitation level which may be increased, over a second period, to a second level. The second level may be a higher level than the first level. The rotation period may be decreased over the first and second periods.

Method for aligning and starting a BLDC three phase motor

A resistive sensing touch panel may include row receiver tracks and column drive tracks. A controller may send and receive control signals and sense signals, respectively, to and from the resistive touch panel. The resistive touch panel may provide sense signals when a touch of the panel is detected. The sense signals may be sampled on a number of rows. When sampling a given row, the controller may change the termination of that row by coupling the end of the sampled row to a resistor having a higher value then terminating resistors coupled to the end of non-sampled rows that are adjacent to the sampled row. The controller may further pull the terminating resistors coupled to the end of the non-sampled adjacent rows to a supply rail voltage while the sampled row is being sampled.

Resistive touch panel with improved termination

A control method for a sensor-less, brushless, three-phase DC motor. The stator coil in the electromagnets inside the motor may be used as the inductive element through which a voltage regulator can regulate the current as a means of regulating the output voltage. The value of the control signal provided to the drivers controlling power to the coils may be calculated based on at least the rail voltage, as measured in real time. This allows for a wide variation of input voltages, while maintaining a relatively constant output power to the motor. In general, by taking into account the value of the rail voltage when determining the final value of the control signal that is applied to the stator coils, the maximum current through the stator coils may be scaled to the same magnitude current that would be expected to flow through the coils if the rail voltage were the rated (nominal) fan/motor voltage, even when the actual rail voltage is different, e.g. higher than the rated fan/motor voltage.

Driving low voltage brushless direct current (BLDC) three phase motors from higher voltage sources

A control method for a sensor-less, brushless, three-phase DC motor. The effects of commutation on the motor may be minimized using a sinusoidal current drive on each electromagnet. The 'off' times and/or the 'on' times of the drive transistors controlling the electromagnets in a full &#x201c;H-bridge&#x201d; configuration drive scheme may be delayed. By overlapping the drive signals to the electromagnets with respect to a commutation command, the effects of switching between electromagnets may be minimized. In addition, the &#x201c;on&#x201d; and &#x201c;off&#x201d; times may also be adjusted during the overlapping to further ensure that the coils continuously conduct current, and that the current does not change direction during the switching. The delays, and hence the overlap times of the coil drive signals may be dynamically controlled, for example by using digital timers, making the response predictable and easily controlled. The present position of the rotor in the motor may be determined using Hall sensors configured in the motor, or it may be determined using the un-energized electromagnets in a motor without Hall sensors.

Drive method to minimize vibration and acoustics in three phase brushless DC (TPDC) motors

A system and method are presented for aligning a rotor in a motor. The motor may include the rotor and a plurality of pairs of electromagnets. One or more pairs of electromagnets may be excited at a first excitation level. The one or more pairs of electromagnets may be less than all of the plurality of pairs of electromagnets. The excitation of the one or more pairs of electromagnets may be increased to a second excitation level over a first period of time. The excitation of the one or more pairs of electromagnets may be decreased to a third excitation level over a second period of time. Exciting the one or more pairs of electromagnets, increasing the excitation, and decreasing the excitation may cause the rotor to stop in a known position.

System and method for aligning a resting rotor to a known position

A control method for a brushless, three-phase DC motor. The motor may include a plurality of electromagnets and a rotor. A voltage induced by rotation of a rotor may be sampled at an expected zero crossing value to produce a first sampled voltage value. An average of a plurality of sampled voltage values, including voltage values sampled at a plurality of prior expected zero crossing values, may be calculated. A delta zero crossing error may be calculated. The delta zero crossing error may be calculated based on a difference between the first sampled voltage value and the calculated average. The plurality of electromagnets may be commutated. Commutation timing for the plurality of electromagnets may be determined based at least in part on the delta zero crossing error.

Brushless three phase motor drive control based on a delta zero crossing error

A control method for a sensor-less, brushless, three-phase DC motor. A pulse-width modulation (PWM) duty cycle may be calculated. A voltage induced by rotation of a rotor may be sampled at a first expected zero crossing value to produce a first sampled voltage value. An average of a plurality of sampled voltage values, including voltage values sampled at a plurality of prior expected zero crossing values and the first sampled voltage value, may be calculated. The first sampled voltage value may be subtracted from the calculated average to produce a delta zero crossing error (ZCE). The current value of an integral term corresponding to a rotational period may be updated according to the sign of the ZCE. The integral term may be updated periodically and multiple times during each rotational period. The ZCE may be subtracted from the integral term, and the resulting value may be used to generate one or more time values. Operation of the motor may be controlled based on the one or more time values and the PWM duty cycle.

Natural commutation for three phase brushless direct current (BLDC) motors

System and method for aligning a rotor to a known position

A control method for a brushless, three-phase DC motor. A voltage induced by rotation of a rotor may be sampled at a first expected zero crossing value to produce a first sampled voltage value. An average of a plurality of sampled voltage values, including voltage values sampled at a plurality of prior expected zero crossing values and the first sampled voltage value, may be calculated. The first sampled voltage value may be subtracted from the calculated average to produce a delta zero crossing error. A pulse-width modulation duty cycle may be adjusted based on the delta zero crossing error. The pulse-width modulation duty cycle may be used to control a rotational velocity of the rotor.

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Tucson, AZ, United States of America

Lynn Russell Kern