L6599 datasheet(28/36 Pages) STMICROELECTRONICS

tên linh kiện	L6599

Giải thích chi tiết về linh kiện	High-voltage resonant controller

PDF	36 Pages

Scroll/Zoom	100%

nhà sản xuất	STMICROELECTRONICS [STMicroelectronics]

Trang chủ	http://www.st.com

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28 / 36 page

Application information

L6599

28/36

Figure 32. Line sensing function: internal block diagram and timing diagram

With reference to Figure 32 the following relationships can be established for the ON

(VinON) and OFF (VinOFF) thresholds of the input voltage:

which, solved for RH and RL, yield:

While the line undervoltage is active there is no PWM activity, thus the VCC voltage (if not

supplied by another source) continuously oscillates between the start-up and the UVLO

thresholds, as shown in the timing diagram of Figure 32.

As an additional measure of safety (e.g. in case the low-side resistor is open or missing, or

in non-power factor corrected systems in case of abnormally high input voltage) if the

Vin

1.25

–

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

–

1.25

-----------

⋅

Vin

OFF

1.25

–

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

1.25

-----------

Vin

OFF

–

⋅

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

1.25

Vin

OFF

1.25

–

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

⋅

L6599 bảng dữ liệu(PDF) 28 Page - STMicroelectronics