NCV78514

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7

Table 8. DIM TABLE (continued)

Symbol

Notes

Unit

Max

Typ

Min

Parameter Description

P_FULL_STARTUP

DC to DC output start up time from valid BAT

applied – Automatic mode / Direct turn ON,

P_FADING_TIME=0

20

25

30

ms

P_DIM_SLOPE

Total time constant of the ILED setting from

dimming mode to normal mode

125

ms

P_DIM_Vih

DIM pin high logic level (4.5 V overdrive)

3.5

V

(Note 8)

P_DIM_Vil

DIM pin low logic level

2

V

P_DIM_IQ

No LED Error

P_UVLO_operating < BAT <

P_OVLO_operating, DIM valid

Referring to ILED derating summary table

10

14

mA

P_DIM_IFAULT

LED Error

P_UVLO_operating < BAT <

P_OVLO_operating, DIM valid

No LED Error

BAT < P_UVLO_operating. DIM valid

Referring to Protection and error management

summary table

0.4

0.7

mA

6. An input duty cycle on DIM pin over 98 % is considered as a 100 % output duty cycle.

7. P_DIM_DC_ACC represents the digital reconstruction of the DIM input duty cycle. The ILED average and P_FULL_STARTUP depend on

the component choice, like Schottky leakages and/or lower capacitor values. Referring to Ta max 105C

8. A 4.5 V overdrive on DIM slope must be respected to not create additional delay on the PWM reconstruction.

Table 9. RSET PARAMETRIC TABLE

Symbol

Parameter Description

Min

Typ

Max

Unit

Notes

P_RSET_RANGE

RSET pull down resistor valid range

0.4

15

kW

P_RSET_RANGE_ACC

RSET range accuracy

10

%

P_TIMEOUT_RSET

Timeout for an out−of−range RCOD value

100

ms

P_SET_RSET

RSET reading duration from an UVLO rising edge

4.5

5

5.5

s

Table 10. LED CURRENT CONTROL WITH LOW VBAT TABLE

Symbol

Parameter Description

Min

Typ

Max

Unit

Notes

P_BAT_LOW

Poor BAT voltage (ADC reading)

8.7

9

9.3

V

P_DEB_BAT

VBAT time before derating, when

VBAT < P_BAT_LOW

7

10

13

ms

P_DTC_BAT

ILED derating time constant in case of

VBAT < P_BAT_LOW, rising and falling

256

ms

P_ILED_BAT_STEP

Step to Step Current De−rating granularity

2.5

%