L6599 datasheet(22/36 Pages) STMICROELECTRONICS

Part #	L6599

Description	High-voltage resonant controller

PDF	36 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

Logo

22 / 36 page

Application information

L6599

22/36

Figure 28. Power vs frequency curve in an resonant half-bridge

As a result, the average input current will smoothly increase, without the peaking that occurs

with linear frequency sweep, and the output voltage will reach the regulated value with

almost no overshoot.

Typically, RSS and CSS will be selected based on the following relationships:

where fstart is recommended to be at least 4 times fmin. The proposed criterion for CSS is

quite empirical and is a compromise between an effective soft-start action and an effective

OCP (see next section). Please refer to the timing diagram of Figure 31 to see some

significant signals during the soft-start phase.

RESONANCE

FREQUENCY

| Z ( f ) | -1

Initial

frequency

Steady-state

frequency

min

start

min

------------

–

----------------------

310

–

⋅

----------------------

L6599 Datasheet(PDF) 22 Page - STMicroelectronics