10

F

9/02

LNK501

Figure 11. Recommended Circuit Board Layout for LinkSwitch using P Package.

LinkSwitch has a minimum leading edge blanking time of

200 ns to prevent premature termination of the on-cycle.

Verify that the leading edge current spike event is below

current limit at the end of the 200 ns blanking period.

3. Thermal check – At peak output power, minimum input

voltage and maximum ambient temperature, verify that the

temperature specifications are not exceeded for LinkSwitch,

transformer, output diode and output capacitors. Enough

thermal margin should be allowed for part-to-part variation

of the R

Under low line, peak power, a maximum LinkSwitch

SOURCE pin temperature of 100

°C is recommended to

allow for these variations.

4. Centered output characteristic – Using a transformer with

nominal primary inductance and at an input voltage midway

between low and high line, verify that the peak power point

occurs at the desired nominal output current, with the correct

output voltage. If this does not occur then the design should

be refined to ensure the overall tolerance limits are met.

Design Tools

Up to date information on design tools can be found at the

Power Integrations Web site: www.powerint.com.

+

-

HV DC

Input

PI-2900-070202

Transformer

+

-

DC Out

D

S

SS

S

S

C

LinkSwitch

Y1-

Capacitor

Input Filter

Capacitor

Output

Capacitor