Switch power adapter switch power adapter test, you must know the main points of the!
New product research and development in the switch power adapter and the experimental process, inspection is a process during which a very important link, r&d is necessary to pay attention to them.
In switch power adapter new product inspection, debugging engineer will often use the oscilloscope is over, so, in the process of debugging is what are the questions we need to pay attention?
Moso technology for these questions are summarized here, we together and see it.
Debugging security in the process of switch power adapter new product debugging, security question is the first one, second is the use of accurate to force and the surface.
When debugging, especially need to pay attention to is the access of primary a switch power supply circuit, the circuit has several hundred volts even on kv high voltage, the primary a switch power supply circuit of the cathode voltage is not zero, so once human exposure by electric shock occurs when the end, this will harm to the safety engineer.
Along the side of the earth connection would amount to a power supply circuit, damage to the input rectifier devices.
Therefore, it is necessary to debug switch power supply through the end of the isolation transformer electrical isolation.
Through isolation transformer in the future, a circuit of the cathode and the probe ground terminal of the oscillograph directly connected, and through the oscilloscope single-phase three-wire plug with ground connection for the maintenance of power supply system, in order to eliminate safety hidden trouble.
Assume skill personnel in the process of debugging is built-in isolation channel skills used by oscilloscope, so even if you don't answer the isolation transformer can also be directly measured, does not appear short circuit phenomenon, but the body contact primary loop by electric shock.
Debugging process of the switch power adapter, therefore, the best is still cut off access to the transformer.
Key waveforms in switch power adapter in the process of new product inspection, engineer's inspection of the key waveform is also very important, the use of the oscilloscope to see when the power switch tube drain voltage waveform can directly reflect the drain, secondary reflected voltage, peak voltage switch tube conduction information such as the pressure drop.
Even if the input voltage is very small, when drain absorption circuit broken will also constitute a high drain peak voltage, and then a power switch tube broken down, need engineers pay attention.
In addition, assuming the power switch tube can not plump conduction, would amount to a large power loss, causing damage to the switch tube overheating.
Close attention to drain voltage waveform, sensitive can be found that the presence of the dangerous situation, in order to timely closed power supply, avoid the parts damage and greater loss.
At the end of the use of oscilloscope probe selection and connection to the switch power adapter measurement in the process of new products and engineer need basis when measuring mission to choose the suitable probe, so will be the most accurate measurement results.
In the process of conventional measurement, with 10 to 1 probe is enough, but for the low rugged signal measurement, we will consider using 1 probe.
When measuring high voltage, such as switch power tube voltage, can choose high voltage probe.
Same, in the current situation of using oscilloscope measurement adapter experimental products, selection of appropriate current probe will be needed.
In general, the oscilloscope probe of the input voltage is 400 v (more
Perhaps 400 VDC, promised to be the peak voltage of short time beyond the planning, assumes that the peak voltage is higher, should choose high pressure probe.
In using the current probe to check the work from time to time, we should try to join to the rugged small loop voltage change.
Such as measurement of the drain current of the power switch tube, shall be connected to the power source circuit switch tube, query the drain current directly.
Assuming that received the drain in the loop, are the high frequency peak voltage will drain attack larger burden.
Setting the rational grounding in the use of the oscilloscope switch power adapter new product inspection, setting the rational grounding is very important as well.
In the inspection process, it was assumed that skilled workers using the probe grounding clip, is equivalent to the grounding path joined a series inductance.
This series inductance and capacitance probe together effect, may cause vibration and overshoot.
Switch power supply, there is a strong electromagnetic radiation, the probe ground wire is too long will also introduce disturb.
Switch power adapter the peak current would disturb the voltage in a circuit board, the address in the space of different measurement, can have is not the same as the waveform, the waveform in shaking is normal phenomenon.