Abstract: A temperature sensor is formed from three initially unfired (or green) ceramic substrates. The first substrate has a temperature sensitive means printed on a first surface. Additionally first and second conducting elements are also printed thereon. The third substrate has a temperature sensitive means in the form of a resistor printed on a first surface. Additionally first and second conducting elements and are also printed thereon. The second substrate is provided with a conducting via in the form of a hole extending through the substrate, the hole being filled with conductive material. The via is adapted to be aligned with the ends of conducting elements. To construct the sensor the first surfaces of substrates are aligned with substrate such that via is aligned with conducting elements. The substrates are then pressed together. Subsequently the substrates are fired to provide the completed sensor.

Abstract: During operation of a 3 phase BLDC motor it is driven by use of a PWM waveform applied to one of the driven phase (curve a). The other driven phase is connected thereto but no driving signal is applied (curve b). The third phase is left floating (curve c). This allows the back EMF in the third phase to be monitored for the purpose of determining rotor position by detection of zero crossing points. The rapid switching of the PWM pulses causes ringing in the back EMF signal indicated for one pulse by the ringed portions 1 of curve c. The ringing in the back EMF signal introduces inaccuracy into position calculations derived from back EMF signal measurement. In order to reduce this ringing, in the present invention, a reverse pulse is applied to the other driving coil shown (curve b) prior to a PWM on pulse. The reverse pulse has a polarity such that it drives the phase current through the linked coils in a direction opposite to that caused by the PWM on pulse.

Abstract: A magnetic angle sensor 100 comprises a bulk substrate; a circular well 101 provided upon the bulk substrate; an even numbered plurality of electrodes 102a-102x spaced at regular intervals in a ring formation over the circular well; and a pair of biasing electrodes for selectively applying a progressive succession of differently directed bias currents 104 to and/or using the said ring of electrodes 102 to provide a succession of Hall potentials indicative of the relative magnitude of successive differently oriented magnetic field components B in the plane of the magnetic angle sensor 100. The sensor 100 operates cyclically and the full progressive succession cycle involves applying and/or using each electrode 102 in the ring at least once for applying a bias current and/or sensing a Hall potential. In such a manner, the full cycle comprises the progressive succession of the axis of measurement of the sensor 100 through a complete rotation within the plane of the sensor.

Abstract: An optical data transceiver is manufactured by forming an integrated control circuit (101) on a suitable substrate, such as a silicon wafer, and then mounting said integrated circuit (101) onto the lead frame (102). Electrical connections may then be made between said integrated circuit (101) and said lead frame (102). The combined assembly comprising the integrated circuit (101) and lead frame (102) is then inserted into the cavity of a mold tool (not shown). A suitable molding compound is injected to encapsulate the combined assembly. The mold tool is provided with a projection (not shown) that is in contact with a portion of the surface of the integrated circuit (101) when the assembly is in the mold tool. As a result, the opening (106), exposing that portion of the surface of the integrated control circuit (101) that was in contact with the projection of the mold tool, is provided.

Abstract: A Hall sensor comprises two separate wells and each having respective contacts provided thereover. An oppositely directed bias current is supplied via contacts. Accordingly, a differential signal can be obtained from the two output contacts. As in each well the middle contact can be precisely centred between the two outer contacts, the intrinsic offset is small. The sensor 300 can be subjected to reversed operation by reversing the bias current direction. This provides a sensor with a low and temperature-stable offset.

Abstract: A temperature sensor is formed from three initially unfired (or green) ceramic substrates. The first substrate has a temperature sensitive means printed on a first surface. Additionally first and second conducting elements are also printed thereon. The third substrate has a temperature sensitive means in the form of a resistor printed on a first surface. Additionally first and second conducting elements and are also printed thereon. The second substrate is provided with a conducting via in the form of a hole extending through the substrate, the hole being filled with conductive material. The via is adapted to be aligned with the ends of conducting elements. To construct the sensor the first surfaces of substrates are aligned with substrate such that via is aligned with conducting elements. The substrates are then pressed together. Subsequently the substrates are fired to provide the completed sensor.

Abstract: Systems and methods for determining the occurrences of pulses for implementing a pulse count monitoring method for driving a brushed DC motor driven by a pulse width modulated (PWM) driving current. The method comprises acquiring the driving current signal; performing peak detection on the acquired signal; identifying the largest peaks and thus determining the occurrence of pulses. The peak detect is implemented by fast peak detection or diode peak detection operable to detect appropriate peak widths as determined by the chosen PWM frequency, duty cycle and PWM pulse height.

Abstract: Tire pressure monitoring system for a vehicle includes sensor units mounted in each tire of the vehicle, each sensor unit being operable to output an RF signal indicative of the pressure in the tire in which it is mounted; a pair of communicator units for receiving signals from said sensor units, said pair of communicator units being provided at different locations on the vehicle; and a control unit connected to said communicator units wherein said control unit is operable to determine which sensor unit is associated with which tire by monitoring the strength of the RF signal received from each respective sensor unit by each communicator unit.

Abstract: The method of the present invention for switching an output driver of the type comprising an n-mos transistor and a p-mos transistor configured in a push-pull arrangement operates by directly monitoring the level of the output signal OUT. The method comprises slowly switching off the input to the initially designated active transistor; monitoring the variation in output voltage level in response thereto; and when a desired change in output level is detected the switching the initially designated output transistor on completely and fast. Using this method the parasitic currents in the diodes are much smaller in time and amplitude.

Abstract: In order to determine the orientation of the rotor of a brushless DC motor 100, a sequence of current pulses may be applied to the stator phases U, V, W by the respective drivers HS0, LS0, HS1, LS1 HS2, LS2. The current generated in the stator phases U, V, W in turn generates a current in a shunt resistor 110. The current in this shunt resistor 110 is monitored by use of a current voltage converter 120 and a comparator 130 to determine when it exceeds a predetermined threshold. The rise time until the threshold current is exceeded is recorded in capture unit 140. A processor unit 150 then calculates a scalar parameter SU, SV, SW for each respective stator phase U, V, W from the recorded rise times associated with each pulse.

Abstract: A method of determining the position of a probe relative to a scale wherein the probe contains a sensor of the type comprising one or more pairs of orthogonal sensing elements X, Y operable to measure properties varying locally with the position of the probe relative to the scale. In use, a sinusoidally varying bias Ix, Iy is applied to each of the elements X, Y. The resultant outputs of elements X and Y are fed to summing means 101 and difference means 102. The summing means 101 is operable to output a summed signal Vsum equal to the instantaneous sum of Vx and Vy. The difference means 102 is operable to output a difference signal Vdiff equal to the instantaneous difference between Vx and Vy. The outputs Vsum and Vdiff are fed into a phase comparator 103, which is operable to determine the phase difference between them. The phase angle between Vsum and Vdiff provides an indication of the position of the probe relative to the scale.

Abstract: In a three phase BLDC motor the rotor position is monitored by detecting the zero crossing points of the induced back EMF signals BEMF_U, BEMF_V, BEMF_W in the phase windings U, V, W. As they are illustrated, the back EMF signals are substantially sinusoidal but they may in other situations be substantially trapezoidal. The three back EMF signals are 120° out of phase with each other. In order to accurately monitor the back EMF in a phase winding, the driving waveform for each phase U, V, W includes an undriven period P close to the expected zero crossing point. The period P can be a preset part of the driving waveform or can be an interruption of the normal driving waveform in response to suitable interrupt signals. In order to determine the zero crossing points of each back EMF signal, two (or more) samples of the back EMF are taken during the undriven period P and used to interpolate the back EMF signal to determine the zero crossing point.

Abstract: An optical data transceiver is manufactured by forming an integrated control circuit (101) on a suitable substrate, such as a silicon wafer, and then mounting said integrated circuit (101) onto the lead frame (102). Electrical connections may then be made between said integrated circuit (101) and said lead frame (102). The combined assembly comprising the integrated circuit (101) and lead frame (102) is then inserted into the cavity of a mould tool (not shown). A suitable moulding compound is injected to encapsulate the combined assembly. The mould tool is provided with a projection (not shown) that is in contact with a portion of the surface of the integrated circuit (101) when the assembly is in the mould tool. As a result, the opening (106), exposing that portion of the surface of the integrated control circuit (101) that was in contact with the projection of the mould tool, is provided.

Abstract: Elements of a sensor system are encapsulated into a single package. The sensor elements are covered with a flexible gel coat and then inserted into a molding tool cavity. Each element may be individually coated with a gel blob, or all elements may by coated with a single gel blob. One or more retractable pins are incorporated into the molding tool and in their normal position are each in contact with the gel. A molding compound is injected into the cavity so as to encapsulate the device and gel coat. When the pins are extracted and the device ejected from the molding cavity, one or more passageways in the molding are left defined by the pins. The passageways expose the flexible gel covering the device elements to the atmosphere. For pressure sensitive elements, the gel, being flexible, transfers the local air pressure to the pressure sensitive element. For optical elements, the exposed gel is preferably removed to allow for the passage of radiation to and from the device elements.