Analog integrated circuit design is mainly achieved through manual circuit debugging and simulation by experienced designers. In contrast, digital integrated circuit design is mostly generated automatically through synthesis using hardware description languages under the control of EDA software.
Analog integrated circuit design has always occupied an extremely important position in integrated circuit design. Since all kinds of signals in our real world are essentially analog signals, analog integrated circuits are indispensable for acquiring signals from the real world, amplifying, filtering, sampling and quantizing them, and finally returning them to the real world to drive them.
Low-voltage power distribution system design principles
1. In workshops or buildings with normal environments, when most electrical equipment is of small to medium capacity and there are no special requirements, trunk-type power distribution is recommended.
2. Radial power distribution is recommended when the electrical equipment is large-capacity, the load is important, or there are special requirements (such as workshops or buildings with humid, corrosive environments or explosion and fire hazards).
3. When some electrical equipment is far from the power supply point, while secondary electrical equipment that is close to each other and has a small capacity can be distributed using a chain-type power distribution system, the number of devices in each chain circuit should not exceed 5, and the total capacity should not exceed 10kW. For sockets of small-capacity electrical equipment, the number of devices in each chain circuit can be appropriately increased when using chain-type power distribution.
4. In high-rise buildings, when supplying power to each distribution point on each floor, it is advisable to use a zoned trunk-type power distribution; however, some large-capacity centralized loads or important loads should be supplied from the low-voltage distribution room using a radial power distribution.
5. Parallel production lines or production units that serve as backups for each other should preferably be powered by different circuits, depending on production requirements; all electrical equipment on the same production line should preferably be powered by the same circuit.
6. In low-voltage power grids with TN and TT grounding systems, three-phase transformers with D,yn11 connection group should be selected as distribution transformers.
7. In low-voltage power grids with TN and TT grounding systems, when a three-phase transformer with Y,yn0 connection is selected, the neutral current caused by a single-phase unbalanced load shall not exceed 25% of the rated current of the low-voltage winding, and the current of one phase shall not exceed the rated current value when fully loaded.
8. When using a low-voltage power grid with 220/380V TN and TT grounding systems, lighting and other electrical equipment should preferably be powered by the same transformer.
9. For power distribution lines introduced from outside the building, isolation devices should be installed indoors near the point of entry for easy operation and maintenance.
The principles of low-voltage power distribution system design are: Design should be tailored to actual conditions, actively adopting advanced technologies and correctly adhering to design standards; effective measures should be taken to address important issues such as power supply safety, energy conservation, and environmental protection; equipment layout should facilitate construction and maintenance management; and the selection of equipment and materials should be comprehensively considered. So how exactly is a low-voltage power distribution system designed?
(1) Design steps of low voltage power distribution system When designing building electrical power supply and distribution system, the load level should be determined according to the building conditions first; then the power supply and distribution scheme should be determined; the power of various electrical equipment should be determined, and on this basis, the power load calculation should be carried out, and various power distribution control equipment and power distribution wires should be selected.
(2) Load Classification: Refer to relevant standards to determine the building's load level. Generally, existing graduation design projects, especially those for multi-story residential buildings, typically involve Class III loads with no special requirements for the power supply. For high-rise residential buildings, Class II loads may exist (primarily for fire protection equipment, such as emergency lighting and elevators). According to standards, these should be supplied by dual power sources, with a dual-power transfer switch at the end of the line. Class III loads are other loads within the residential building.
(3) Power distribution scheme
Consult relevant standards to clarify the forms of low-voltage power distribution. Most existing graduation projects focus on residential electrical design, so the forms of low-voltage power distribution are basically a combination of trunk and radial types. For specific meanings, please refer to relevant materials.
(4) Load Calculation Methods Load calculation methods include the installed power per unit building area method, the demand factor method, the binomial method, and the utilization factor method. Residential buildings generally use the demand factor method. Commercial outlets generally use the unit area method.
(5) Standard for calculating load of residential buildings: Commercial outlet capacity: not less than 100w per square meter; Independent garage capacity: designed at 2kw.
How to effectively design analog integrated circuits? SOP! SOP! SOP! I'll say it three times because it's so important! Although the chip design process and the company's current SOPs are not entirely the same, the principle is the same: effective process management and control can greatly reduce the probability of design errors. Secondly, leave plenty of design margin. IC tape-out costs are high and the cycle time is long. If problems are found during testing, there must be a backup plan to deal with them. Therefore, the adequacy of the circuit design margin is crucial. Finally, to quote an industry saying, "Circuits are like bricks and mortar, systems are like a building. Chip design engineers must consider problems from a system perspective; otherwise, they will only see the trees and not the forest." Only by considering chip design from a system perspective can excellent chip products be produced. Low-voltage power distribution systems are major users of low-voltage electrical appliances, which are generally installed in various dedicated distribution cabinets and control cabinets.
