Power Supplies by Acopian

Acopian

Power Supplies

Power Supply Comparisons

  Switching Regulated Linear Regulated Unregulated
Circuit Design complex moderately complex simple
Part Count
high medium low
Load Regulation
0.05% to 0.5% .005% to 0.2% +10% (1/2 load to No Load (NL))
-10% (1/2 load to Full Load (FL))
Line Regulation 0.05% to 0.2% 0.005% to 0.05% directly proportional to
AC input change
Ripple (RMS) 10 mv to 25 mv 0.25 mv to 1.5 mv 0.5 v to 5 v
Transient
Recovery
300 microseconds
(1/2L to FL)
50-100 microseconds
(NL to FL)
N/A
Efficiency 70-85% 40-60% 90-95%
Hold-up Time 15-30 milliseconds 1-2 milliseconds  
EMI high very low very low
Leakage high low very low
Size
(power density)
small size
(high power density)
large size
(low power density)
medium size
(medium power density)
Weight
(Power to Weight Ratio)
light
(high)
heaviest
(low)
heavy
(low)
Power Factor 0.6 - 0.7% without PFC
>0.95% with PFC
0.6 - 0.7%  0.6 - 0.7% 
Cooling convection or fan convection convection
Isolation yes yes yes
Input Voltage
Range
90 - 132 VAC
(without PFC)

     and/or

180 - 264 VAC
(without PFC)

-----------------
90 - 264 VAC
(with PFC)
105 - 125 VAC
     and/or
210 - 250 VAC 
0 - 125 VAC
0 - 250 VAC
Output directly
proportional to input
Values in chart above are for comparison purposes only.


Switching Regulated Power Supply
A Switching regulated power supply regulates the output voltage by the use of a complex high frequency switching technique. They have moderately good load and line regulation, but significantly higher ripple and output noise than linear regulated power supplies. They also have slow transient response, but high efficiency.

Typical applications


Linear Regulated Power Supply
A linear regulated power supply regulates the output voltage by dropping excess voltage in a series dissipative component. They use a moderately complex regulator circuit to achieve very low load and line regulation. They also have very little ripple and very little output noise.

Typical applications
General purpose use - including, but not limited to:


Unregulated Power Supply
An unregulated power supply does not contain any form of regulating circuitry. Output load ‘regulation’ is determined by the inherent transformer impedance and circuit resistance. Output line ‘regulation’ is directly proportional to the AC input change. Unregulated power supplies are adequate for non-critical loads such as relays, solenoids, and lamps and are a lower cost alternative to regulated supplies.

Typical applications
General purpose use - including, but not limited to: