GE Industrial Solutions 3A Digital PicoDLynx - Manual (Page 14)

GE
Data Sheet
3A Digital PicoDLynx TM : Non-Isolated DC-DC Power Modules
3Vdc –14.4Vdc input; 0.45Vdc to 5.5Vdc output; 3A Output Current
April 29, 2013 ©2013 General Electric Company. All rights reserved. Page 14
Analog Feature Descriptions
Remote On/Off
The module can be turned ON and OFF either by using the
ON/OFF pin (Analog interface) or through the PMBus interface
(Digital). The module can be configured in a number of ways
through the PMBus interface to react to the two ON/OFF
inputs:
• Module ON/OFF can be controlled only through
the analog interface (digital interface ON/OFF
commands are ignored)
• Module ON/OFF can be controlled only through
the PMBus interface (analog interface is ignored)
• Module ON/OFF can be controlled by either the
analog or digital interface
The default state of the module (as shipped from the factory)
is to be controlled by the analog interface only. If the digital
interface is to be enabled, or the module is to be controlled
only through the digital interface, this change must be made
through the PMBus. These changes can be made and written
to non-volatile memory on the module so that it is
remembered for subsequent use.
Analog On/Off
The 3A Digital PicoDLynx TM power modules feature an On/Off
pin for remote On/Off operation. Two On/Off logic options
are available. In the Positive Logic On/Off option, (device
code suffix “4” – see Ordering Information), the module turns
ON during a logic High on the On/Off pin and turns OFF
during a logic Low. With the Negative Logic On/Off option,
(no device code suffix, see Ordering Information), the module
turns OFF during logic High and ON during logic Low. The
On/Off signal should be always referenced to ground. For
either On/Off logic option, leaving the On/Off pin
disconnected will turn the module ON when input voltage is
present.
For positive logic modules, the circuit configuration for using
the On/Off pin is shown in Figure 39. When the external
transistor Q2 is in the OFF state, the internal transistor Q1 is
turned ON, and the internal PWM #Enable signal is pulled low
causing the module to be ON. When transistor Q2 is turned
ON, the On/Off pin is pulled low and the module is OFF. A
suggested value for R
pullup
is 20k Ω.
For negative logic On/Off modules, the circuit configuration is
shown in Fig. 40. The On/Off pin should be pulled high with
an external pull-up resistor (suggested value for the 3V to
14V input range is 20Kohms). When transistor Q2 is in the
OFF state, the On/Off pin is pulled high, transistor Q1 is
turned ON and the module is OFF. To turn the module ON, Q2
is turned ON pulling the On/Off pin low, turning transistor Q1
OFF resulting in the PWM Enable pin going high.
Digital On/Off
Please see the Digital Feature Descriptions section.
Figure 39. Circuit configuration for using positive On/Off
logic.
Figure 40. Circuit configuration for using negative On/Off
logic.
Monotonic Start-up and Shutdown
The module has monotonic start-up and shutdown behavior
for any combination of rated input voltage, output current
and operating temperature range.
Startup into Pre-biased Output
The module can start into a prebiased output as long as the
prebias voltage is 0.5V less than the set output voltage.
Analog Output Voltage Programming
The output voltage of the module is programmable to any
voltage from 0.6dc to 5.5Vdc by connecting a resistor
between the Trim and SIG_GND pins of the module. Certain
restrictions apply on the output voltage set point depending
on the input voltage. These are shown in the Output Voltage
vs. Input Voltage Set Point Area plot in Fig. 41. The Upper
Limit curve shows that for output voltages lower than 1V,
the input voltage must be lower than the maximum of
14.4V. The Lower Limit curve shows that for output voltages
higher than 0.6V, the input voltage needs to be larger than
the minimum of 3V.
10K
Q2
22K
Q1
22K
Rpullup
+3.3V +VIN
GND
+
_
V
ON/OFF
ON/OFF
I
ENABLE
DLYNX MODULE
10K
Q2
22K
Q1
22K
Rpullup
+3.3V
+VIN
GND _
+
I
ON/OFF
V
ON/OFF
ENABLE
DLYNX MODULE