What are the components of a power adapter? What problems should be paid attention to potting glue?

The Power Adapter is an indispensable electronic product in our life, we will charge it almost every day, although it looks like the design is very simple, but in fact the power adapter is also composed of many precise electronic components, simple division, there should be four major components, today the charger manufacturers and you talk about the power adapter what components? What problems should be paid attention to potting glue?

The four components of a power adapter

1. Main circuit: mainly includes the following parts

(1) Impulse current limiting: limit the impulse current of the input side at the moment when the power is switched on.

(2) Input filter: its function is to filter the clutter of the power grid and prevent the clutter generated by the machine from being fed back to the power grid.

(3) Rectification and filtering: the AC power supply of the power grid is directly rectified into smooth direct current.

(4), inverter: the direct current after rectification into high frequency alternating current, which is the core part of high frequency switching power supply.

(5) Output rectification and filtering: provide stable and reliable DC power supply according to load needs.

2, control circuit: on the one hand from the output end of the sample, compared with the set value, and then to control the inverter, change its pulse width or pulse frequency, so that the output stability, on the other hand according to the data provided by the test circuit, through the protection circuit identification, to provide a variety of protection measures for the power supply control circuit.

3, detection circuit: provide protection circuit in operation of various parameters and various instrument data.

4. Auxiliary power supply: realize the software (remote) startup of the power supply, and supply power to the protection circuit and control circuit (PWM chip).

Power adapter potting glue need to pay attention to what problems?

1, waterproof, potting glue will be the electrical part of the power adapter tightly wrapped, completely isolated from the outside world; What water, water, acid, alkali and salt can not get to the circuit element, can improve the ability of waterproof, moisture-proof and anti-corrosion. So you choose the glue to good liquidity, liquidity is not good how can deep penetration completely sealed; Moreover, the bonding force should also be available, otherwise, after sealing for a long time, the alternating hot and cold and component separation is useless, and the service life performance of the power adapter is also affected.

2, thermal conductivity, power adapter is a work rate product, that is, conversion, control, output energy. Adaptor work to heat, such as switch tube, transformer, electrolytic capacitor, inductance, which is not heating devices and are afraid of heat devices. What to do? We must transmit the heat as quickly and as much as possible. So the glue must have good thermal conductivity, it can be said that the higher the thermal conductivity of the expected glue, the better. The life of the electrolytic capacitor in the power supply shrinks by half with every increase of ten degrees of temperature, but you can't add heat sink to it; Transformer, inductance temperature a high many parameters are changing the whole design is difficult to improve, you are not good to add a heat sink to him.

3, insulation strength, basically all glue is not conductive, but pay attention to, like epoxy class AB glue curing reaction is not completely may be a little local conductive. And in order to save the sand in it, that is hard to say. First, your sand is not dehydrated processing, but also your sand will some other elements interfere with the curing; Whether the ratio of AB agent is reasonable, whether the mixture is sufficiently uniform, and whether other conditions are met.

4, environmental protection requirements, adapters are generally certified. It depends on whether the products provided are consistent with the certification. The price difference between environmental protection and non-environmental protection materials is still quite a lot.

5, flame retardant requirements, generally look at the flame retardant test in UL. General requirement 94-V0 above.