Temperature Sensors for Braking Systems
Thermal sensors range from bare thermocouples and Resistive Temperature Devices (RTDs) to more sophisticated infrared non-contact sensors that directly, consistently, and accurately measure a material's temperature. There are two types of thermal sensors: contact and non-contact.
Contact temperature sensors measure their own temperature. The assumption is that the temperature of the object that the sensor contacts is the same as the sensor because the two are in thermal equilibrium (there is no heat flow between them.) Most commercial and scientific non-contact temperature sensors measure the thermal radiant power of the infrared or optical radiation that they receive from a known or calculated surface area or volume.
Transient Voltage Suppressors for Braking Systems
A Transient Voltage Suppressor (TVS) is a device used to protect circuits from electrical overstress such as that caused by electrostatic discharge, inductive load switching and lightning. The TVS limits damaging voltage spikes by utilizing the avalanche action of a heavy-duty silicon PN junction. The TVS acts by reducing the transient spike in the signal to a non-destructive level. Until it sees a transient, a good TVS is passive and does not affect the circuit.
Accelerometers for Braking Systems
An accelerometer is a sensor that determines the direction and magnitude of the inertia that they experience and convert that into an electrical signal. Most accelerometers today use MEMS (microelectromechanical) technology because of the high integration level of MEMS devices with silicon-based electronic circuits. Accelerometers are inertial sensors that can be used to detect orientation, vibration, acceleration, and more. This information is then translated into electrical signals and used to monitor or as control feedback to improve overall mechanical performance. The automotive industry has been one of the main drivers behind MEMS technology, which includes inclinometers and gyroscopes.
Voltage Regulators for Braking Systems
A voltage regulator produces a constant level of voltage over time regardless of load, changes in power supply, or temperature. Voltage regulators are used in applications where voltage levels must be maintained at a specific voltage, at a steady level, regardless of how much power is drawn by the system. Unlike a voltage reference, precision is not as important with a voltage regulator and regulators vary widely in implementation and precision. A Low Drop Out regulator is often used because it maintains the same voltage level to within a specified lowest value before it fails to maintain regulation.
Memory for Braking Systems
Memory stores data and programs for later use. Some memory is Read-Only, which means nothing new can be stored, and other memory is Read/Write memory where a processor can read from or write to this method of data storage. Some memory is non-volatile, meaning that a power source is not required to preserve stored information. Other types of memory lose their information and become a blank slate every time power is removed from the device. Two types of memory, EEPROM and flash, share many of the same qualities ??? in fact, flash memory is often considered an advanced form of EEPROM. However, one of the largest functional distinctions between the two lies in how the memory can be erased: unlike flash, EEPROM is erasable at a more precise, byte-wise level. For this reason among others, EEPROM continues to see industry use in applications that must store small amounts of non-volatile data.
System Basis Chips for Braking Systems
System Basis Chips (SBC) are a generic term for a chip that combines several popular functions and serves to highly integrate a bundle of technologies or functions that are most often used in a particular industry or application. High levels of integration are beneficial because they allow several functions to operate in a smaller space without connecting glue-logic, traces, or cables that interface separate circuits with different functions. In short, they save space and can free up design time by already providing mudane but required design work.
Clocks for Braking Systems
Clock technology is more expensive and more complicated at higher frequencies. A lower frequency clock can be used and then multiplied to achieve the desired clock rate; however any jitter (error) is also multiplied. (Jitter is shakiness in the signal, caused by electro-magnetic radiation or the influence of nearby signals.) Circuitry supporting clock function should be selected for low noise.
Watchdog Timers for Braking Systems
The function of a Watchdog Timer (WDT) is to trigger a system reset or some corrective action when the main processor stops regularly sending a signal to the watchdog timer. Embedded systems rarely have a "ctrl-alt-delete" such that a human can reset them if they suddenly stop working, and a power cycle may not be feasible. Therefore, embedded systems with critical functions may have a WDT to force a reboot of the processor in case it is unable to execute instructions or simply does not send the WDT a signal in time.
Processors for Braking Systems
The term "processor" refers to an electronic device that performs computational functions and carries out the instructions of a stored program. Other terms for processor are microprocessor, central processing unit, and digital signal processor. Essentially, the processor refers to "the brains of a computer."
3-Phase Pre-Drivers for Braking Systems
Designers of power electronic circuits must often drive power switches that feed DC, AC, or power signals to a variety of workloads. Logic-level electronic circuits provide the driving signals. In general, however, the power sources and their loads have reference levels different from that of the control circuitry (ground). MOSFET selection begins by choosing devices that can handle the required current, then giving careful consideration to thermal dissipation in high current applications.
Gate Drivers for Braking Systems
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.
System Basis Chips for Braking Systems
System Basis Chips (SBC) are a generic term for a chip that combines several popular functions and serves to highly integrate a bundle of technologies or functions that are most often used in a particular industry or application. High levels of integration are beneficial because they allow several functions to operate in a smaller space without connecting glue-logic, traces, or cables that interface separate circuits with different functions. In short, they save space and can free up design time by already providing mudane but required design work.
Power MOSFETs for Braking Systems
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. MOSFETS are often used as the switching elements for regulation as well as for power factor correction (PFC).
High Side MOSFETs for Braking Systems
The terms ???high-side??? and ???low-side??? are sometimes applied to MOSFETs, referring to the switching configuration in which the transistor is typically used. MOSFETs used for low-side switching operate by connecting and disconnecting the load with ground. In contrast, high-side MOSFETs, which are placed between the power supply and load, switch on and off both the load current and load voltage.
High-side switching is used in many applications where the load must be kept at ground level when turned off. In this case, P-channel MOSFETs are often used for the sake of simplicity. N-channel MOSFETs can be used, but they require additional circuitry to ensure V
GS
remains above the threshold voltage and the FET stays on. However, N-channel MOSFETs are still attractive for high-side switching because they use negative charge carriers (electrons) instead of holes, resulting in on-resistances up to three times lower. For most typical applications, N-channel MOSFETs are used almost exclusively for low-side switching.
Low Side MOSFETs for Braking Systems
The terms ???high-side??? and ???low-side??? are sometimes applied to MOSFETs, referring to the switching configuration in which the transistor is typically used. MOSFETs used for low-side switching operate by connecting and disconnecting the load with ground. In contrast, high-side MOSFETs, which are placed between the power supply and load, switch on and off both the load current and load voltage.
High-side switching is used in many applications where the load must be kept at ground level when turned off. In this case, P-channel MOSFETs are often used for the sake of simplicity. N-channel MOSFETs can be used, but they require additional circuitry to ensure V
GS
remains above the threshold voltage and the FET stays on. However, N-channel MOSFETs are still attractive for high-side switching because they use negative charge carriers (electrons) instead of holes, resulting in on-resistances up to three times lower. For most typical applications, N-channel MOSFETs are used almost exclusively for low-side switching.
