LED5000 datasheet(37/52 Pages) STMICROELECTRONICS

部件名	LED5000

功能描述	3 A monolithic step-down current source with dimming capability

PDF	52 Pages

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制造商	STMICROELECTRONICS [STMicroelectronics]

网页	http://www.st.com

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37 / 52 page

LED5000

Application notes - alternative topologies

Doc ID 023951 Rev 1

37/51

Equation 57

R1 must be dimensioned to limit the D1 rated power so it is an inexpensive small signal

Zener diode.

The overvoltage protection plays an important role for the inverting buck-boost topology. In

fact, in case of open row, the output voltage tends to diverge thus exceeding the input

voltage absolute maximum rate and the device would be damaged (see

Equation 50). The

overvoltage protection limits VOUT and thereby it protects the device in case of load

disconnection.

To design the compensation network for the inverting buck-boost topology please refer to

paragraph

Chapter 6.4: Compensation network design for alternative topologies.

Figure 26.

Inverting BB PCB layout (component side)

Figure 27.

Inverting BB PCB layout (bottom side)

OUT

ZENER_DIODE

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AM13510v1

AM13511v1

LED5000 数据表(PDF) 37 Page - STMicroelectronics