MAX17512ATP+ Maxim Integrated, MAX17512ATP+ Datasheet - Page 11

• Manufacturer Part Number: MAX17512ATP+
• Description: Current & Power Monitors & Regulators High Speed Valley Current Regulator
• Manufacturer: Maxim Integrated

Specifications of MAX17512ATP+

• Product: Current Regulators
• Supply Voltage - Max: 18 V
• Supply Voltage - Min: 6.5 V
• Input Voltage Range: 6.5 V to 18 V

In applications where it is desired to reduce the inter-
nal linear regulator power dissipation to maximize the
output current capability of the device, an external 5V
rail (V
shown in the
The device’s EN/UVLO pin serves as an enable/disable
input, as well as an accurate programmable undervolt-
age lockout (UVLO) pin. The device does not commence
switching operations unless the EN/UVLO pin voltage
exceeds 1.225V (typ). The device turns off if the EN/
UVLO pin voltage falls below 1.225V (typ).
A resistor-divider from the input bus to ground can be
used to divide-down and apply a fraction of the input
voltage to the EN/UVLO pin. The values of the resistor-
divider can be selected such that the EN/UVLO pin volt-
age exceeds the 1.225V (typ) turn-on threshold at the
desired input DC bus voltage, as shown in
given values of startup input voltage (V
value (R
assuming a 49.9kI resistor for R
Figure 3. Configuring the MAX17512 to Use an External 5V
Regulator (V
REG
TOP
) can be used to power AVCC and PVCC, as
High-Speed, Constant On-Time, Valley Current
REG
Startup Voltage Setting (EN/UVLO)
) for the divider can be calculated as follows,
Figure
C
R
)
V
REG
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AVCC
3.
V
CC
V
REG
MAX17512
LDO
BOTTOM
AVIN
PVCC
Regulator for Tracking Applications
START
.
Figure
), the resistor
4. For
where R
The device regulates the valley point of the inductor current
depending on the current-command voltage applied at
the ICMD pin. For example, the device regulates the valley
current to 5A with Q250mA for a 1.842V current-command
voltage. The current-command voltage (V
applied at the ICMD pin for a given inductor valley current
(I
where I
The device can deliver a maximum current of 6A and
hence a clamp on the voltage on the current-command
voltage is incorporated. Therefore, the appropriate
current-command voltage range is 0.442V to 2.15V, which
corresponds to a valley current range of 220mA to 6A.
Figure 4. Programming EN/UVLO
VALLEY
Programming the Valley Current (ICMD)
VALLEY
V
TOP
) can be calculated as follows:
ICMD
R
TOP
=
=
and R
R
BOTTOM
is in amps.
R


R
TOP
(
BOTTOM
I
VALLEY
BOTTOM
V
DC
EN/UVLO
are in kI and V
×
×
0.28



MAX17512
V
1.225
START
MAX17512
)
+
0.442 in volts
−
1 in k





START
ICMD
Ω
is in volts.
) to be