DS_IPM24S0B0_03202007
8
DESIGN CONSIDERATIONS
Remote On/Off
The IPM series power modules have an On/Off control
pin for output voltage remote On/Off operation. The
On/Off pin is an open collector/drain logic input signal
that is referenced to ground. When On/Off control pin is
not used, leave the pin unconnected.
The remote on/off pin is internally connected to +5Vdc
through an internal pull-up resistor. Figure 27 shows the
circuit configuration for applying the remote on/off pin.
The module will execute a soft start ON when the
transistor Q1 is in the off state.
The typical rise for this remote on/off pin at the output
voltage of 2.5V and 5.0V are shown in Figure 17 and 18.
Vo
On/Off
Vin
GND
IPM
Q1
RL
Figure 27: Remote on/off implementation
FEATURES DESCRIPTIONS
Over-Current Protection
To provide protection in an output over load fault
condition, the unit is equipped with internal over-current
protection. When the over-current protection is
triggered, the unit enters hiccup mode. The units
operate normally once the fault condition is removed.
Output Voltage Programming
The output voltage shall be externally adjustable by use
of a Trim pin. The module output shall be adjusted by
either a voltage source referenced to ground or an
external resistor be connected between trim pin and Vo or
ground. To trim-down using an external resistor, connect
a resistor between the Trim and Vo pin of the module. To
trim-up using an external resistor, connect a resistor
between the Trim and ground pin of the module. The
value of resistor is defined below. The module outputs
shall not be adversely affected (regulation and operation)
when the Trim pin is left open.
Trim up
(Vout-0.7)*1.43
Rtrim =
Vadj-Vout
(KΩ)
Trim Down
(Vadj-0.7)*5.36
Rtrim =
Vout-Vadj
(KΩ)
Rtrim is the external resistor in KΩ
Vout is the desired output voltage
IPM can also be programmed by applying a voltage
between the TRIM and GND pins (Figure 30). The
following equation can be used to determine the value of
Vtrim needed for a desired output voltage Vo:
