Basic specifications

AN4214

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3

Basic specifications

Table 1. Basic specifications of SMPS

Parameters

Limits

Rated input voltage range

Minimum voltage operation (in case of line sag)

Input overvoltage shutdown

Input supply frequency (fL)

47 - 63 Hz

Input / output isolation

Yes, > 2.7 kV

Power factor correction

Yes, > 0.95

THD

< 20%

Nominal output voltage

75 V ± 1.5 V

Load current

0.7 A

1. The no load power consumption is measured after removing the resistors used for input OVP (R2, R6, R7).

< 0.75 W

Total output power

55 W

Efficiency (full load for wide mains variations)

> 85%

Output voltage pk-pk ripple(2.fL)

< 20%

Topology

Single stage HPF flyback

Maximum ambient temperature

50

C

Table 2. Transformer specification

Parameters

Limits

Max. output power

Max. 55 W

Primary inductance

0.62 ± 0.01 mH at 50 KHz

Primary side leakage inductance

< 10 µH at 50 KHz

Peak primary current

2.8 A

Average primary current

0.9 A

Saturation current

3.5 A

Operating switching frequency

50 KHz min. to 125 KHz max.

Core size

ER28/17/11

Ferrite material

N87, EPCOS

Bobbin

12 pins, horizontal

Dielectric strength

> 2.7 kV

Approx air gap (central limb)

0.8 mm