Temperature Sensors for Seat Controls
A temperature sensor is a device that measures cold or heat as a temperature or temperature
gradient. Many applications require some implementation of temperature sensing and measurement.
For motors, the operating temperature inside the case is monitored by the processor and set to
alarm or shut down at temperatures higher than the normal operating temperature of the motor. If
a motor runs at too high of a temperature for too long, it can reduce the life of the motor.
Operating temperature is an indication of the general operating health of the motor. Higher
temperatures inside the motor case can mean too high of a load is placed on the motor, since as
load increases, motor current consumption increases to meet the load requirements.
Hall Effect Sensors for Seat Controls
Hall Effect sensors are magnetically biased transducers that vary output voltage or current in
response to changes in a magnetic field. Hall Effect sensors can be designed to sense rotary
movement of a motor shaft. The rotation of the motor shaft changes the IC's position with
respect to the magnets, and thus detects the change in flux density. The output of the IC is
converted to a linear output over 90 degrees of shaft travel. The Hall Effect sensor gets its
name from Edwin Hall, who, in 1879 discovered that a voltage difference can be produced across
an electrical conductor where the magnetic field is perpendicular to the direction of current
flow.
Voltage Regulators for Seat Controls
DC/DC regulators are circuits that convert DC voltage from one level to another and maintain
that voltage at a constant level. Electronic systems often have several sub-circuits, each with
its own voltage level requirement that may be higher or lower than the main power supply.
Step-up (boost) converters raise a voltage to a higher level, while step-down (buck) converters
lower it.
Signal Conditioners for Seat Controls
Analog signal conditioners are used to preserve the accuracy and legibility of measurements. In
a control system, measurements such as temperature, pressure, level, flow, weight, or speed, for
example, are used to determine if more or less control should be applied. This measurement, or
feedback, typically has a long way to travel before it is used by the processor, displayed, or
recorded. Signal conditioners boost and "clean" the signal to help maintain signal integrity.
CAN Transceivers for Seat Controls
CAN is an acronym for Controller Area Network and refers to a fault-tolerant communications
protocol that is flexible for system design, supports multiple network topologies, and has
become a de facto standard for high integrity serial communications in industrial and automotive
embedded applications. In a CAN network, several short pieces of data like a motor's run status,
temperature, or RPM is broadcast over the entire network at up to 1 megabit per second (Mbps.)
DC/DC Converters for Seat Controls
DC/DC convertors are circuits that convert DC voltage from one level to another and maintain
that voltage at a constant level. Electronic systems often have several sub-circuits, each with
its own voltage level requirement that may be higher or lower than the main power supply.
Step-up (boost) converters raise a voltage to a higher level, while step-down (buck) converters
lower it.
Microcontrollers for Seat Controls
Microcontrollers are similar to processors in that they perform computational functions and
carry out the instructions of a computer program. A microcontroller, however, is often used for
embedded applications— as opposed to central processing units (CPUs) which are more
commonly designed for general-purpose computing. Furthermore, microcontrollers are meant to
reduce size and cost by including integrated peripherals such as flash memory, analog-to-digital
converters (ADCs), digital-to-analog converters (DACs), device drivers, transceivers for various
communications protocols, and more.
Gate Drivers for Seat Controls
It is a common misconception that most power MOSFETs or IGBTs can be driven directly from a
logic circuit or microcontroller. The reality is that most of these high-power transistors
require current and voltage levels that far exceed the capacity of control electronics.
Essentially, a gate driver is a power amplifier which serves as an interface between a low-power
PWM signal and the gate of an IGBT/MOSFET transistor.
MOSFETs for Seat Controls
MOSFETs are also for power switching circuits. Unlike bipolar junction transistors (BJTs), the
competing type of power transistor, MOSFETs do not require a continuous flow of drive current to
remain in the ON state. Additionally, MOSFETs can offer higher switching speeds, lower switching
power losses, lower on-resistances, and reduced susceptibility to thermal runaway. In
switched-mode power supplies (SMPSs), MOSFETS are often used as the switching elements for
regulation as well as for power factor correction (PFC).
