What are the basic components on the ATX power board?
If you collect a number of ATX power objects, disassemble the housing and carefully observe and summarize the circuit board inside it. We will find that a number of packaged components are used on the circuit board of the ATX power supply. These components include resistors, capacitors, inductors, diodes, transistor, FET, and so on.
The author calls these elements, which are available on almost all circuit boards, "basic components". For the reasons of performance and cost, the basic components used in ATX power supply are mainly in-line type, supplemented by chip. We will provide an in-depth introduction to its knowledge below.
The learning of the basic components is mainly to master their types of recognition, nominal value recognition and measurement, good or bad judgment, and so on. Although a large number of basic components, but its principle and structure are relatively simple, only in the case of the use of multimeter can easily and accurately judge its good or bad.
Chip on the ATX power circuit board.
By observing, in addition to being able to find a large number of basic components on the ATX power circuit board, there are often several chips. In essence, a chip is an organic combination of a large number of basic components. Chip manufacturers package mature circuit-specific circuits into chips in the form of integrated circuits, which simplifies the circuit and improves the reliability of the circuit.
The function of the chip is single and clear. Together with the peripheral components of the chip, the chip forms a relatively independent and interconnected circuit on the ATX board.
Not all components can be easily integrated into the chip, and the inductor is an example.
As an integrated circuit, the chip's internal integrated components are also damaged (such as electrostatic breakdown), which causes the circuit in which it is located to lose its original function. This damage manifests on the chip, which is causing the relevant pins/modules of the chip to be disabled. At this point, only the entire chip can be replaced.
Each chip corresponds to a data sheet prepared by the manufacturer. The data sheet is the specification of the chip. The data sheet details the technical definitions, working principles, working timing, electrical parameters, appearance dimensions, welding processes, storage conditions, etc. Of the technology chip. Therefore, information. Some data sheets even contain public circuit, which is the most accurate and authoritative technical data we need to know the chip.
In general, the chips used by the ATX power board can be divided into four categories according to their functions.
(1) A PWM (Pulse Width Modulation, pulse width modulation (PWM) chip that generates a switching pulse source (oscillation source) necessary for a switching power supply, such as TL494, KA7500, etc., in the main power supply portion.
(2) An operational amplifier, such as a LM339, for comparing two input voltage signals.
(3) Optocoupler for feedback and voltage stabilization control, such as PC817.
(4) Protection chips, such as WT7510, for monitoring output voltage and output control signals (PSON, PG).