Datasheet
UVLO
OVLO
R1
R2
TP1
4
3
R3
LM5069
V
IN
R3 =
2.5V x R2
(V
OVH
- 2.5V)
R2 =
V
OVH
- V
OVL
21 PA
R4 =
2.5V x R1
(V
UVL
- 2.5V)
R1 =
V
UVH
- V
UVL
21 PA
UVLO
OVLO
R1
R2
TP1
4
3
R3
LM5069
V
IN
R4
www.ti.com
UVLO/OVLO Input Voltage Thresholds
Figure 6. UVLO, OVLO Inputs (Option B)
The four resistor values are calculated as follows:
Choose the upper and lower UVLO thresholds (V
UVH
) and (V
UVL
).
(10)
(11)
Choose the upper and lower OVLO threshold (V
OVH
) and (V
OVL
).
(12)
(13)
CAUTION: The Absolute Maximum Rating for the OVLO pin is 7V. Do not let the voltage on OVLO
exceed 7V when VIN is at its maximum value. The Absolute Maximum Rating for the UVLO pin is 100V.
Option C: The minimum UVLO level is obtained by positioning the jumper at JMP1 on pins 1-2, and
leaving R4 open, resulting in the configuration shown in Figure 7. Q1 is switched on when the voltage at
VIN reaches the POR
EN
threshold (≊8.4V). The OVLO thresholds are set by R2 and R3, and their values
are calculated using the procedure in Option B. The value for R1 is not critical, and can be as supplied.
SEE THE CAUTION ABOVE.
Figure 7. Minimum UVLO Threshold, Adjustable OVLO
Option D: The OVLO function can be disabled by removing the jumper from JMP1. The UVLO thresholds
are set by R1 and R4 using the procedure in option B or C above.
7
SNVA184B–September 2006–Revised May 2013 AN-1522 LM5069 Evaluation Board
Submit Documentation Feedback
Copyright © 2006–2013, Texas Instruments Incorporated