lm5066pmhx National Semiconductor Corporation, lm5066pmhx Datasheet - Page 23

• Manufacturer Part Number: lm5066pmhx
• Description: High Voltage System Power Management And Protection Ic With Pmbus
• Manufacturer: National Semiconductor Corporation

The four resistor values are calculated as follows: - Choose
the upper and lower UVLO thresholds (V
- Choose the upper and lower OVLO threshold (V
(V
As an example, assume the application requires the following
thresholds: V
56V. Therefore V
values are:
R1 = 200 kΩ, R2 = 16.8 kΩ
Option D: The OVLO function can be disabled by grounding
the OVLO pin. The UVLO thresholds are set as described in
Option B or Option C.
OVL
).
UVH
UV(HYS)
= 36V, V
= 4V, and V
UVL
= 32V, V
OV(HYS)
OVH
FIGURE 11. Programming the Four Thresholds
UVH
= 60V, and V
= 4V. The resistor
) and (V
FIGURE 12. UVLO = POR
OVH
UVL
) and
OVL
).
(22)
(23)
(24)
(25)
=
23
R3 = 190 kΩ, R4 = 8.1 kΩ
When the R1-R4 resistor values are known, the threshold
voltages and hysteresis are calculated from the following:
Option C: The minimum UVLO level is obtained by connect-
ing the UVLO/EN pin to VIN as shown in
switched on when the VIN voltage reaches the POR
old (
values are calculated using the procedure in Option B.
≊
8.6V). The OVLO thresholds are set using R3, R4. Their
EN
V
UV(HYS)
30115950
30115941
= R1 x 20 µA
Figure
www.national.com
EN
12. Q1 is
thresh-
(26)
(27)
(28)
(29)