LTC4417

MURALIPALANI said:

How to define IOVUV(HYS) between 50nA ≤ IOVUV(HYS) ≤ 500nA or else in the datasheet where the formula was mentioned.

From page 12 in the datasheet:


An R_HYS of 124kΩ gets you an I_OVUV(HYS) of 500nA, while 1.24MΩ gets 50nA.

How to calculate R1, R2, R3 for (UV1-OV1), R4, R5, R6 for (UV2-OV2),  R7, R8, R9 for (UV3-OV3) My supply range is 3 inputs are same range UV-4 Working-5 OV-5.7 Voltages. With internal Hysteresis 30mV.

Would you explain me above mentioned question?

MURALIPALANI said:

How to calculate R1, R2, R3 for (UV1-OV1), R4, R5, R6 for (UV2-OV2),  R7, R8, R9 for (UV3-OV3) My supply range is 3 inputs are same range UV-4 Working-5 OV-5.7 Voltages. With internal Hysteresis 30mV.

GIVEN: internal 30mV hysteresis:

UVTH(FALL)=1V
OVTH(RISE)=1V
UVTH(RISE)=1.03V
OVTH(FALL)=0.97V

WANT:

UVFALL=4V
OVRISE=5.7V

Choose bias current at OVRISE so the sum of RTOP, RMID, RBOT are ~1MΩ.

RSERIES=RTOP+RMID+RBOT=1.14MΩ
IBIAS=5uA

FIND RBOT:

RBOT=OVTH(RISE)/IBIAS
RBOT=1V/5uA=200kΩ

FIND RMID:

RMID=[{UVTH(FALL)/UV(FALL)}*RSERIES]-RBOT
RMID=[{1V/4V}*1.14MΩ]-200kΩ
RMID=85kΩ
[Use standard value of 84.5kΩ]

FIND RTOP:

RTOP=RSERIES-RMID-RBOT
RTOP=1.14MΩ-85kΩ-200kΩ
RTOP=855kΩ
[Use standard value of 845kΩ]

Simulate in LTspice to confirm the UV-OV window.