AN3011 datasheet(10/37 Pages) STMICROELECTRONICS

10 / 37 page

Testing the board

AN3011

10/37

Doc ID 16043 Rev 1

Testing the board

2.1

Typical board waveforms

Figure 7

and 8 show the drain current and the drain voltage waveforms at the nominal input

voltages, which are 115 VAC and 230 VAC when at maximum load (2.2 A). Figure 9 and 10

show the same waveforms for the same load condition, but with the input voltages at the

minimum 90 VAC and the maximum 265 VAC.

The converter is designed to operate in continuous conduction mode (in full-load condition)

at low-line. CCM (continuous conduction mode) allows the reducing of the root mean square

currents value, at the primary side, in the power switch inside the VIPer, and in the primary

winding of the transformer; at the secondary side in the output diode (D4) and in the output

capacitors (C9 and C14). Reducing RMS currents means reducing the power dissipation

(mainly in the VIPer) and the stress on the above mentioned components.

Figure 7.

Drain current and voltage at full-

load 115 VAC

Figure 8.

Drain current and voltage at full-

load 230 VAC

Figure 9.

Drain current and voltage at full-

load 90 VAC

Figure 10.

Drain current and voltage at full-

load 265 VAC

AN3011 Datasheet(PDF) 10 Page - STMicroelectronics