AN4007 datasheet(11/33 Pages) STMICROELECTRONICS

11 / 33 page

AN4007

Test board: design and evaluation

Doc ID 022455 Rev 2

11/33

Figure 8.

Light load consumption at different output power with brownout

1.5

Typical board waveforms

Drain voltage and current waveforms were reported at nominal input voltages and for the

minimum and the maximum voltage of the converter input operating range.

Figure 10 and 11

show the drain current and the drain voltage waveforms at the two nominal input voltages

and full load, while

Figure 9 and 12 show the same waveforms at the minimum and

maximum input voltage range respectively.

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

at low line. CCM (continuous conduction mode) allows the reduction 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 (D2) and in the

output capacitors (C3 and C4). Reducing RMS currents means reducing the power

dissipation in the VIPer™ and the stress of the secondary side components.

AM11346v1

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Input voltage [Vac]

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