as follows:

=

2

2

(A6)

=

1

+

;

(A7).

mains voltage range, in turn defines the range of

Fig. A3 shows the diagram of (A6) while Tab. A1

voltage ranges, as well as the corresponding

To complete the characterization of the transition

between DCM and CCM it is convenient to define

Input Voltage at

which the operation is on the

= √

2

(A8).

In synchronized converters it is possible to define

ing frequency at which the operation is on the

=

2

2

(A9).

The peak primary current at transition is then:

√

2

=

1

⋅

1

+

=

(A9).

In case of CCM operation, equation (A4) still applies but the timing relationships (A2) change as follows:

=

(A10),

where

n

Figure A2. Equivalent Input Voltage vs. DC

Input Voltage

Figure A3. Characterization of the

transi-

tion DCM

⇐⇒ CCM

AN1049 APPLICATION NOTE

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