STR5A460 datasheet(21/32 Pages) SANKEN

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STR5A460 Series

STR5A460-DSE Rev.3.5

SANKEN ELECTRIC CO., LTD.

Aug. 21, 2018

https://www.sanken-ele.co.jp/en

2) Set Switching Frequency, fSW2

When fSW at the intersection of ILH2_f and ILH2_DCM is

in the range of fMIN to fTYP as shown in Figure 9-3,

fSW2 is set to that value. When fSW is out of the range

as shown in Figure 9-4, fSW2 is set to the limited value

which is fMIN or fTYP of the over range side.

3) Calculate On-duty, DON2

The condition of DDCM2 : < DCCM2

4) Calculate ILH2, ILL2, and ILR2

ILH2 is the value at the intersection of fSW2 which is

given in the previous 2) and ILH2_DCM. Otherwise, ILH2

is given below.

(B-2-1-2-4) ILH2

If ILH2 is IDLIM_MIN or more, try the procedure 1 in

Section (B-2-1-1-5) to decrease it.

(B-2-1-2-5) On-time, tON2

If tON2 is less than 400 ns, try the procedure 1 in

Section (B-2-1-1-5) to increase it.

(B-2-1-2-6) IDRMS2, ILRMS2

These are given by substituting ILH2, ILL2, DON2, and

DCCM2 for ILH1, ILL1, DON1, and DCCM1 in the equation of

Section (B-2-1-1-7), respectively.

(B-2-1-3) Inductor Current specification

The saturation current of the inductor should be

enough larger than IDLIM_MAX.

The rating current refers to the equation of RMS in

Section (B-2-1-1-7).

(B-2-2) Parameter Calculation Assigned LUSER

Parameter calculation assigned LUSER at VDCIN_MIN and

VDCIN_MAX is similar to the way of Section (B-2-1-2)..

Parameters assigned LUSER are given by substituting

the input voltage and LUSER for VDCIN_MAX and LCALC.

If the conditions of calculation aren’t satisfied,

increase LUSER setting, or decrease IOUT setting, and then

try to calculate again.

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