L6599AD datasheet(17/35 Pages) STMICROELECTRONICS

No. de pieza	L6599AD

Descripción Electrónicos	Improved high-voltage resonant controller

PDF	35 Pages

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Fabricante Electrónico	STMICROELECTRONICS [STMicroelectronics]

Página de inicio	http://www.st.com

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17 / 35 page

L6599A

Application information

Doc ID 15308 Rev 7

17/35

Figure 22.

Oscillator internal block diagram

The following approximate relationships hold for the minimum and the maximum oscillator

frequency respectively:

Equation 1

After fixing CF in the hundred pF or in the nF (consistently with the maximum source

capability of the RFmin pin and trading this off against the total consumption of the device),

the value of RFmin and RFmax is selected so that the oscillator frequency is able to cover

the entire range needed for regulation, from the minimum value fmin (at minimum input

voltage and maximum load) to the maximum value fmax (at maximum input voltage and

minimum load):

Equation 2

A different selection criterion is given for RFmax in case burst mode operation at no load is

used (see

Section 7.2: Operation at no load or very light load).

()

max

min

max

min

;

⋅

;

min

max

min

max

min

−

⋅

L6599AD Datasheet(PDF) 17 Page - STMicroelectronics