The fundamental reason for the price gap of power adapters

Industry news 2018/10/25 11:47:13 share to

In our daily life, we often touch the charger / power adapter, and often encounter some problems in the process of using, such as common bad contact, voltage instability or insurance burnout and other failures, then how can we check and eliminate it? Repair.

Regular manufacturer's charger/power adapter has a nameplate indicating power, input/output voltage and current. It is worth noting that the input voltage range. Generally speaking, a charger/power adapter with an input voltage of 110V-240V can be used worldwide and is suitable for all countries and regions.

Common failures and maintenance of charger / power adapter:

Line fault

Line failure, including poor power line failure, poor contact oxidation contact, and so on. Check whether the input and output lines are energized. If the line fails, it can be solved by replacing the power cord.

Two, the output voltage is too high.

The high output voltage generally comes from the voltage sampling and voltage stabilizing control circuit. In the closed control loop composed of DC output, sampling resistance, error sampling amplifier such as TL431, optocoupler, power control chip and other circuits, any part of the problem will cause the output voltage to rise.

Three, the output voltage is too low.

The following are the main reasons for low output voltage:

1. Switching power supply load short circuit fault (especially DC / DC converter short circuit or poor performance, etc.), at this time, first disconnect all the load of the switching power supply circuit, check whether the switching power supply circuit fault or load circuit fault. If the load circuit is disconnected and the voltage output is normal, it means that the load is too heavy or the switching power supply circuit is still abnormal.

2 the output voltage end filter capacitor or rectifier diode failure can be judged by replacement method.

3. The performance of the switch tube decreases, resulting in the switch tube can not be turned on normally, so that the internal resistance of the power supply increases and the load capacity decreases.

4. The bad switching transformer not only causes the output voltage to drop, but also causes the switching tube insufficient excitation and thus damages the switching tube.

5300V filter capacitor is poor, resulting in poor power load capacity, and the output voltage of one load will drop.

Four, the insurance burns or explode.

Mainly check rectifier bridge, diode, switch tube and 300 volt on the large filter capacitor and other parts. Cause the insurance to burn, blacken, may also be the problem that the interference circuit causes.

In particular, it should be noted that the breakdown of the switch tube leads to the safety burning, usually burning out the power control chip and current detection resistance. Thermistors are also easily burned together with the insurance.

The common troubles and maintenance of the charger/power adapter are mentioned here. In addition, we should pay attention to the daily maintenance and maintenance of the charger/power adapter, which can reduce the occurrence of troubles and effectively prolong the service life.

Five, the safety valve is normal, no output voltage.

The safety valve is normal, and no output voltage indicates that the switching power supply is not working or entering the protection state. The first step is to check the start-up voltage of the start-up foot of the power control chip. If there is no start-up voltage or the start-up voltage is too low, check whether the components connected to the start-up foot and the start-up resistance are leakage.

If the power control chip is normal, the fault can be found quickly through the above monitoring. If there is a starting voltage, the output of the control chip is measured whether there is a high or low level jump at the moment of start-up. If there is no jump, it shows that the control chip is damaged, the peripheral oscillatory circuit components are damaged or the protection circuit is in trouble. The control chip is replaced and the peripheral components are checked one by one. The number of cases is poor or damaged.

 

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