L99LD01 datasheet(22/69 Pages) STMICROELECTRONICS

部件名	L99LD01

功能描述	High efficiency constant current LED driver for automotive applications

PDF	69 Pages

Scroll/Zoom	100%

制造商	STMICROELECTRONICS [STMicroelectronics]

网页	http://www.st.com

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22 / 69 page

Functional description

L99LD01

22/69

DocID025319 Rev 3

The external resistor applied between pin RSF and ground is setting the converter working

frequency. The voltage applied on pin RSF is the internal reference reported by the source

follower structure which is a constant voltage of 1.21 V. The converter frequency is directly

related to the current flowing through the RSF pin. Figure 12 reports the behavior of

frequency converter as function of the external resistor RSF and IRSF as function of

converter frequency. As above mentioned the converter oscillator spread parameters (dither

effect) are adjustable via SPI.

Dither effect is disabled by default during standalone operation, but it is possible enabling it

simply connecting the SDI pin to 5 V voltage.

Figure 11. Internal structure of main converter oscillator

L99LD01 数据表(PDF) 22 Page - STMicroelectronics