NCV78514

www.onsemi.com

8

Table 11. IC THERMAL THRESHOLDS TABLE

Symbol

Parameter Description

Min

Typ

Max

Unit

Notes

P_TJWARN

Warning threshold for a LED Current de−rating

starting value

130

C

P_TJ_HYST

Rearming threshold after a direct TSD (no derating)

135

C

P_TJ_REG

LED Current de−rating end value

(ILED = P_ILED_TJILED over this threshold)

150

C

P_TJ_OFF

Protection for the maximum Junction Temperature.

DC to DC is turned off over this value.

170

C

P_ILED_TJ

End de−rating output current ratio, percentage of

the ISET

60

%

P_TJ_FALL

Response time + timer, falling for rearming

20

ms

P_ILED_TJ_STEP

Step to Step Current De−rating ratio

1.3

2.5

%

Table 12. THERMAL COEFFICIENT SENSOR PIN TABLES

Symbol

Parameter

Min

Typ

Max

Unit

Notes

P_VTCSSTART

Derating start voltage on TCS

0.57

* VVDD

P_VTCSEND

Derating end voltage on TCS

0.39

* VVDD

P_ISTOP

Relative to ISET, Default Option

60

%

P_TFAULT

Timer before an error is reported on DIM pin

20

30

100

ms

P_TDER_SLOPE

Derating slope in percentage of ILED

0.15

0.2

0.25

%/ms

P_TCS_PD

Internal pull down for pin floating event, measured

at 1 V

0.3

2

MW

Table 13. SNSP AND SNSN THRESHOLDS TABLE

Symbol

Parameter Description

Min

Typ

Max

Unit

Notes

P_VOUT_L

LED under voltage threshold (LED string shorted),

falling

1.5

V

P_VOUT_SU

Start up threshold, Current sense feedback, rising

1.825

V

P_VOUT_L_IDLE_SU

Blanking time where the VLED low comparator is

not activated during start up, from switching activity

10

ms

P_VOUT_H

LED over voltage threshold (LED string opened),

rising

62

64

66

V

P_SNSPN_OPEN

Of the programmed ICOD. The comparator is

debounced.

135

195

%

P_SNSPN_SHORT

Differential voltage of the VLED N and P pins.

The comparator is debounced.

5

mV

P_SNSPN_SHORT_SU

Blanking time at start up, from switching activity

(sum of Ton in DIM dimming case)

8

ms

Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product

performance may not be indicated by the Electrical Characteristics if operated under different conditions.