PI3749-00-EVAL1 Datasheet, PDF (16/26 Pages) Vicor Corporation – Cool-Power® ZVS Switching Regulators

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:
nnDynamic V_OUT margining
nnProgrammable Sync Phase Delay
Fault telemetry including:
nnInput and Output Overvoltage
nnInput and Output Undervoltage
nnInternal Bias Supply Undervoltage
nnOvertemperature Protection
nnMulti Tiered Current Limit reporting
Cool-Power^® ZVS Switching Regulators
Page 16 of 26
Rev 1.8
03/2017
vicorpower.com
800 927.9474
PI3749-x0