PSU(Power Supply Unit) is a system converting an external AC or DC power to the right one for each system and machine and it’s a fundamental and critical parts because the system goes wrong or broken if PSU does not supply stable power to the system. There are two kinds of PSU(Power Supply Unit). One is a Linear type and the other is a Switching mode type.
The old linear type has limitation in efficiency, weight and size so the SMPS (Switching Mode Power Supply) has come to the market to overcome and enhance these limitations from Linear type.
SMPS (Switching Mode Power Supply) has been applied and used for consumer and industrial machine requiring small size, Light weight and Bigger capacity.
SMPS requires high and reliable technology because it converts AC line frequency (50Hz ~ 60Hz) to DC and use a very high frequency ( Several dozen KHz ~ Several hundred KHz) at DC-DC switching stage.
|Input EMI filter||AC-DC Convert||DC-DC S/W convert||Output filter & Output|
|To prevent the noise for AC input line and also prevent the switching noise to coming into AC input line.||Temporary DC power conversion before the EMI filtered power goes into system power||Create DC power by low band filter to remove the noise and ripple||Output filer the DC power before the output to System power|
2. Development Flow & Process of User demand type SMPS
|Spec Definition||Select Topology||Prototype Making||System Interface Tes||Reliability Test, Safety Approval||Mass Production|
(Dozens ~ hundred Watt)
ㆍDesign experience &
|Small Size SMPS
(a few ∼ Dozens Watt)
|Resonance||LC||ㆍSmall and Light
ㆍSuperior in EMI
|Small but Big capacity,
|Soft Switching||ㆍ Strength of LC
ㆍLower power and
PDP, LCD TV