LM3554TMXSLASHNOPB datasheet(10/47 Pages) TI1

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LM3554

SNVS549C – JUNE 2009 – REVISED FEBRUARY 2016

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Typical Characteristics (continued)

VIN = 3.6 V, LEDs are Lumiled PWF-4, COUT = 10 µF, CIN = 4.7 µF, L = FDSE0312-2R2 (2.2 µH, RL = 0.15 Ω), TA = 25°C,

unless otherwise specified.

(1)

The typical curve for overvoltage protection (OVP) is measured in closed loop using the Typical Application Circuit. The OVP value is

found by forcing an open circuit in the LED1 and LED2 path and recording the peak value of VOUT. The value given in Electrical

Characteristics is found in an open-loop configuration by ramping the voltage at OUT until the OVP comparator trips. The closed loop

data can appear higher due to the stored energy in the inductor being dumped into the output capacitor after the OVP comparator trips.

At worst case is an open circuit condition where the output voltage can continue to rise after the OVP comparator trips by approximately

IIN× sqrt (L/COUT).

Figure 20. VIN Monitor Thresholds vs Temperature

Figure 21. OVP Thresholds vs VIN

(1)

Figure 22. Short Circuit Current Limit vs VIN

VLEDI = 2 V

Figure 23. Indicator Current vs VIN

(Torch Brightness Register Bits[7:6] = 00)

VLEDI = 2 V

Figure 24. Indicator Current vs VIN

(Torch Brightness Register Bits[7:6] = 01)

VLEDI = 2 V

Figure 25. Indicator Current vs VIN

(Torch Brightness Register Bits[7:6] = 10)

LM3554TMX/NOPB データシート(PDF) 10 Page - Texas Instruments