PI3749-X0 Datasheet, PDF (16/26 Pages) Vicor Corporation – 16V to 34VIN, 12V to 28VOUT, 240W Cool-Power ZVS Buck-Boost

Overtemperature Protection
The internal package temperature is monitored to prevent
internal components from reaching their thermal maximum.
If the Overtemperature Protection threshold is exceeded
(T_OTP), the regulator will complete the current switching cycle,
enter a low power mode, set a fault flag, and will soft-start
when the internal temperature decreases by more than the
Overtemperature Restart Hysteresis (T_{OTP_HYS}).
Pulse Skip Mode (PSM)
PI3749-x0 features a hysteretic Pulse Skip Mode to achieve high
efficiency at light loads. The regulator is setup to skip pulses if
V_EAO falls below the Pulse Skip Threshold (V_{EAO_PST}). Depending
on conditions and component values, this may result in single
pulses or several consecutive pulses followed by skipped pulses.
Skipping cycles significantly reduces gate drive power and
improves light load efficiency. The regulator will leave Pulse Skip
Mode once the control node rises above the Pulse Skip Mode
threshold (V_{EAO_PST}).
Variable Frequency Operation
The PI3749-x0 is preprogrammed to a fixed, maximum, base
operating frequency. The frequency is selected with respect to
the required power stage inductor to operate at peak efficiency
across line and load variations. The switching frequency period
will stretch as needed during each cycle to accommodate low
line and or high load conditions. By stretching the switching
frequency period, thus decreasing the switching frequency, the
ZVS operation is preserved throughout the input line voltage
range maintaining optimum efficiency. ­
IMON Amplifier
The PI3749-x0 provides a differential amplifier with a level
shifted, SGND referenced output, the IMON Pin, which is useful
for sensing input or output current on high voltage rails. A fixed
gain of 20:1 is provided over a large common mode range.
When using the amplifier, the ISN pin must be referenced to
the common mode voltage of the ISP pin for proper operation.
See Absolute Maximum Ratings for more information. If not in
use, the ISN and ISP pins should be connected to SGND and the
IMON pin left floating.
I²C Interface Operation
PI3749-20 devices provide an I²C digital interface that enables
the user to:
Device Configuration Options:
n Dynamic V_OUT margining
n Programmable Sync Phase Delay
Fault telemetry including:
n Input and Output Overvoltage
n Input and Output Undervoltage
n Internal Bias Supply Undervoltage
n Overtemperature Protection
n Multi Tiered Current Limit reporting
Cool-Power^® ZVS Switching Regulators
Page 16 of 26
Rev 1.6
09/2016
vicorpower.com
800 927.9474
PI3749-x0