Voltage Reference for Low Voltage DC Motor Motors
A voltage reference produces a constant level of voltage over time regardless of load, changes in power supply, or temperature. Voltage references are used in power supplies, analog-to-digital converters, digital-to-analog converters, and many other applications where voltage levels must be maintained at a steady level. Without a voltage reference, precision is greatly affected and may render the device inoperable. Voltage references can vary greatly in performance. A voltage reference for a power supply might hold its output to within only a few percentage points off of its nominal or stated value; however, a voltage reference to instrumentation-level standards are measured in parts per million regarding stability and precision to the nominal or specified value.
Processors for Low Voltage DC Motors
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."
Drivers for Low Voltage DC Motors
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.
Digital Isolation for Low Voltage DC Motors
Isolation is critical to protect both an electronics system and the user from potentially hazardous voltages, or where a high level of electrical isolation between electronics systems is necessary. Digital isolators are known for their speed of data transmission, high level of magnetic immunity, and long life expectancy. Used in combination with isolated power supplies, these devices protect circuits from high voltages, prevent current flow between remote system grounds, and avoid the creation of current loops. Digital isolators can be used to implement isolation in designs without the cost, size, power, performance, and reliability constraints found with optocouplers.
ADCs for Low Voltage DC Motors
An Analog-to-Digital Converter (ADC or A/D converter) measures the magnitude of an input analog signal and converts it to a digital number that is proportional to the magnitude of the voltage or current. An ADC often converts signals collected from the real-world to digital signals for processing. One of the more important specifications of an ADC is the resolution that it offers, which is the number of discrete values (represented in bits) that the ADC produces in relation to the analog signal it is converting. The more bits, the higher the resolution. A higher resolution yields a more accurate approximation of the analog input.
Signal Conditioning for Low Voltage DC Motors
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. Just as it is difficult to make out details in a fuzzy picture, information in a signal can become “fuzzy” and detailed information is lost without signal conditioners to help. Most often signal conditioners for analog control signals (usually 4 – 20mA for I/O) are operational amplifiers with characteristics suited for the purpose of preserving the signal. For example, without signal conditioners a signal could be so fuzzy (or noisy) that it triggers an alarm based on error introduced along the way to the processor, not on real information. Since noise is usually unpredictable, acceptable control without signal conditioners would be nearly impossible.
RS-485 for Low Voltage DC Motors
RS-485 is an electrical-only standard, in contrast to complete interface standards which define physical, functional, and electrical specifications. RS-485 signaling can be used with many protocols such as Profibus, Interbus, Modbus, or BACnet, depending on the requirements of the end user. Sometimes controller area network (CAN) or EtherNet are preferred for network requirements. RS-485 has a 10 Mbps maximum data rate (@ 40 feet) and a 4000 foot maximum cable length (@100 kbps.) RS-485 is robust and well suited for long distance networking in noisy environment.
CANs for Low Voltage DC Motors
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.) CAN is meant for applications that have to report and consume numerous but small pieces of data consistently among nodes and has the ability to self-diagnose and repair data errors. CAN is well-suited to environments with machinery, since CAN is designed to be reliable in rugged environments that include interference or introduce noise. CAN is also well-suited to the transportation industry.
USB Receptacles for Low Voltage DC Motors
USB plugs and receptacles are designed to reduce human error by their unique shape; they fit together in only one way. USB plugs and receptacles are Type A (connecting to hosts or hubs) or Type B (connecting to devices) and are available 3 sizes: standard, mini, and micro. Type A plugs always face upstream, Type B faces downstream. USB is used in many applications covering all areas of electronics that require communication, but more commonly with devices that need fast or easy connections for interaction with computers. Since USB provides a small charging current as well, it is becoming a de facto standard for charging portable devices.
USB for Low Voltage DC Motors
USB is a standard connection interface between computers and digital devices. A USB transceiver is a physical layer device that prepares data for transmission and then sends to, and receives data from, another transceiver. The transceiver detects connection and provides the low level USB protocol and signaling. The term "transceiver" indicates an implementation of both transmit and receive functions. It transmits and receives, encodes and decodes data, provides error indication, implements buffers to stage data until it can be managed, and adjusts for the clock rate from the serial stream on the USB SuperSpeed bus to match that of the “link layer” higher up on the communication stack.
ESD for Low Voltage DC Motors
Electrostatic Discharge (ESD) is a naturally occurring phenomenon. If you have ever been zapped by a socks-wearing kid who has just discovered static charge build up, you have experienced ESD first hand. ESD is like a miniature, localized lightning bolt caused by an electrical discharge. ESD can have seriously damaging effects on an integrated chip or system and cause poor performance or failure later on by merely weakening the circuits.
Batteries for Low Voltage DC Motors
Batteries are a portable, wireless means of storing energy via the use of self-contained chemical cells. They can be for one-time use and discarded, or recharged and reused. In essence, a battery is an energy storage device, but can only store and release electricity as direct current. Direct current is a flat line at a given amplitude (until it declines as it is exhausted), versus alternating current, which is a sinusoidal wave.
Battery Management for Low Voltage DC Motors
Battery management generally refers to a collection of functions such as the battery charger, protection, and a fuel gauge. Battery charging circuits are used to recharge batteries and are available in linear or switching topologies. They can be completely autonomous in operation or used with a microcontroller. Battery protection circuits are an electronic safeguard to prevent damage to internal electronics in the event of reverse battery installation, accidental short circuiting, or other inappropriate operation. A battery fuel gauge, or state-of-charge (SOC) indication, has evolved from a simple warning to a more complex system level use of the information, such as soft shutdown to prevent data loss.
System Power for Low Voltage DC Motors
DC/DC controllers and regulators are needed for system power requirements. System power refers to the power that drives the motor itself and may be stepped down in turn to provide a power source for conversion for use by the processor core and I/O. DC/DC controllers are used here to condition the voltage supply and reduce the level of the voltage source from an external DC source. There may be several voltage buses routed through a circuit or printed circuit board for distribution to devices requiring different operating voltages. Ideally, several devices will operate over a similar range, reducing the need for several regulators delivering disparate voltages.
Core and I/O Power for Low Voltage DC Motors
DC/DC Controllers and regulators are required for the processor and to drive the signals for input and output (I/O). This power is typically stepped down in voltage level with a regulating device from another on-board source. There may be several voltage buses routed through a circuit or printed circuit board for distribution to devices operating under different supply voltages, or for separate purposes to isolate ground loops, for instance. Ideally, several devices will operate over a similar range, reducing the number of regulators for a smaller overall footprint.