PRM48AY480X400A00 Datasheet, PDF (28/44 Pages) Vicor Corporation – High Efficiency Converter

Pin Functions
+IN, -IN
Input power pins
+OUT, -OUT
Output power pins. Module cannot sink current.
ENABLE
This pin turns the supply on and off. The pin is both an input and an
output and can provide the following features:
n Delayed Start: upon application of voltage (>UVLO) to the
module power input and after t_off, the ENABLE pin will source a
constant 90 μA current.
n Output enable: When ENABLE is allowed to pull up above the
enable threshold, the ENABLE pin will pull up to 5 V with
1.8 mA source capability, and the module will be enabled.
n Output disable: ENABLE may be pulled down externally in order
to disable the module. Pull down resistance should be less than
235 Ω to SGND.
n Fault detection flag: The ENABLE 5 V voltage source is
internally turned off when a fault condition is detected.
ENABLE control should be implemented using an open collector
configuration. It is not recommended to drive this pin externally.
VAUX: Auxiliary Voltage Source
Use this pin to power external devices with a non-isolated 9 V
supply, with up to 5 mA load capability, switched with ENABLE
input. Do not place a capacitor over 0.04 µF on this pin.
SGND: Signal Ground
This is a low current pin which provides a Kelvin connection to the
PRMs internal signal ground. Use this pin as the ground reference for
external circuitry and signals to avoid voltage drops caused by high
currents on power returns. In array configurations, SGND pins
should be star connected at a single point. A series resistor (~1Ω) to
the star location is recommended to decouple return currents.
VC: VTM Control
This output pin is used to temporarily provide VCC voltage to
connected VTMs during start up. The pulse is nominally 14 V, 10 ms
wide. A VTM can self-power once its input voltage reaches its
minimum specified input voltage. The PRM output must be checked
to make sure it reaches this threshold voltage before the VC pulse
expires.
TRIM
The TRIM pin is used to select the operating mode and to trim
the PRM output when Adaptive Loop operating mode is
selected. The TRIM pin has an internal pull-up to V_{CC_INT}
through a 10 kΩ resistor.
Operating Mode Select:
If TRIM is pulled below 0.45 V during the first startup after V_IN
is applied, Remote Sense / Slave operation is selected.
Otherwise, Adaptive Loop operation is selected.
This selection persists until V_IN is removed from the part, and is
not changed by fault or disable events.
Output Voltage Trim:
Sets the output voltage of the PRM in Adaptive Loop operation.
PRM48Ay480x400A00
If TRIM is permitted to pull up to 3.20 V or higher during start
up, trim is disabled, and the output is set to the nominal of 48.0 V.
If TRIM is held between 1.00 V to 2.75 V during start up, trim
is enabled, and the output is scaled by a factor of 20 resulting
in an output voltage range of 20.0 V to 55.0 V.
This selection persists until the PRM is restarted with the
ENABLE pin, or due to fault auto-recovery.
AL: Adaptive Loop (Adaptive Loop Operation)
This input pin allows you to set the Adaptive Loop load line.
Every volt on this pin represents 0.5 Ω of positive output slope.
There is an internal 10 kΩ pullup resistor to V_{CC_INT}. If AL is
permitted to pull up to 3.20 V or higher during start up, the
Adaptive Loop load line is disabled.
This selection persists until the PRM is restarted with the
ENABLE pin, or due to fault auto-recovery.
VT: VTM Temperature (Adaptive Loop Operation)
This pin is used in the Adaptive Loop compensation algorithm to
account for the VTM output resistance variation as a function of
temperature. The VTM TM pin provides this voltage, scaled as the
temperature in K (Kelvin) divided by 100, so 25°C is 2.98 V. Leave
disconnected or pull below 1.9 V to disable. The adjustment is fixed
at 0.3%/°C relative to the value at 25°C
REF: Reference (Adaptive Loop Operation)
This output pin allows you to monitor the internal reference voltage
in Adaptive Loop Operation. During normal operation it represents
the output voltage scaled by a factor of 20.
In Adaptive Loop Operation this pin is for monitoring purposes only
and should not be driven or loaded externally.
REF_EN: Reference Enable (Remote Sense Operation)
In Remote Sense Operation this pin outputs a regulated 3.25 V, 4 mA
voltage source. It is enabled only after successful start up of the PRM
powertrain. REF_EN is intended to power the output current
transducer and also the voltage reference for the external control
loop. Powering the reference generator with REF_EN helps provide a
controlled start up, since the output voltage of the system is able to
track the reference level as it comes up.
SHARE (Adaptive Loop and Slave Operation)
This bus sets the output current level for all the PRM modules when
operating in an array (master-slave configuration). Connect them
together among the modules in the shared bus. One PRM should be
configured as a master by connecting TRIM for Adaptive Loop
Operation. All other PRMs should be configured as slaves by pulling
their respective TRIM pins low. This pin can be used to monitor the
error voltage externally. 0 to 100% load is represented by a voltage
between 0.79 V and 7.40 V.
CONTROL NODE (Remote Sense Operation)
In Remote Sense Operation, this is the input to the modulator which
determines the powertrain timing and ultimately the module output
power. An internal 0.5 mA current sink is always active. The bi-
directional buffer between CONTROL NODE and the modulator has
two states. In normal operation, CONTROL NODE will be above the
0.79 V switching threshold, and will drive the modulator through the
buffer. An internal 7.40 V clamp determines the maximum output
power that can be requested of the modulator.
PRM^TM Regulator
Page 28 of 44
Rev 1.4
11/2015
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