GE Industrial Solutions 12V PicoTLynx 6A - Manual (Page 14)

GE
Data Sheet
12V PicoTLynx TM 6A: Non-Isolated DC-DC Power Modules
4.5Vdc –14Vdc input; 0.59Vdc to 5.5Vdc output; 6A Output Current
May 2, 2013 ©2013 General Electric Company. All rights reserved. Page 14
1.5MEG
Q2
VIN+
GND
+
PWM Enable
ON/OFF
ON/OFF
_
MODULE
I
V
Rpullup
ON/OFF
22K
Q1
22K
Figure 43. Circuit configuration for using negative On/Off
logic.
Overcurrent Protection
To provide protection in a fault (output overload) condition, the
unit is equipped with internal current-limiting circuitry and can
endure current limiting continuously. At the point of
current-limit inception, the unit enters hiccup mode. The unit
operates normally once the output current is brought back into
its specified range.
Overtemperature Protection
To provide protection in a fault condition, the unit is equipped
with a thermal shutdown circuit. The unit will shutdown if the
overtemperature threshold of 140 o C is exceeded at the thermal
reference point T
ref
. The thermal shutdown is not intended as a
guarantee that the unit will survive temperatures beyond its
rating. Once the unit goes into thermal shutdown it will then
wait to cool before attempting to restart.
Input Undervoltage Lockout
At input voltages below the input undervoltage lockout limit,
the module operation is disabled. The module will begin to
operate at an input voltage above the undervoltage lockout
turn-on threshold.
Output Voltage Programming
The output voltage of the 12V Pico TLynx TM 6A modules can be
programmed to any voltage from 0.59dc to 5.5Vdc by
connecting a resistor between the Trim and 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. 44.
The Upper Limit curve shows that for output voltages of 0.9V
and lower, the input voltage must be lower than the maximum
of 14V. The Lower Limit curve shows that for output voltages of
3.8V and higher, the input voltage needs to be larger than the
minimum of 4.5V.
0
2
4
6
8
10
12
14
16
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
Output Voltage (V)
Input
V
o
lt
a
g
e (
v
)
Lower Limit
Upper Limit
Figure 44. Output Voltage vs. Input Voltage Set Point
Area plot showing limits where the output voltage can
be set for different input voltages.
Without an external resistor between Trim and GND pins,
the output of the module will be 0.59Vdc. To calculate
the value of the trim resistor, Rtrim for a desired output
voltage, use the following equation:
( )
Ω






−
= k
Vo
Rtrim
591 . 0
91 . 5
Rtrim is the external resistor in kΩ
Vo is the desired output voltage.
Table 1 provides Rtrim values required for some common
output voltages.
Table 1
V
O, set
(V) Rtrim (KΩ)
0.6 656.7
1.0 14.45
1.2 9.704
1.5 6.502
1.8 4.888
2.5 3.096
3.3 2.182
5.0 1.340
By using a ±0.5% tolerance trim resistor with a TC of
±100ppm, a set point tolerance of ±1.5% can be
achieved as specified in the electrical specification.
Remote Sense
The 12V Pico TLynx TM 6A power modules have a Remote
Sense feature to minimize the effects of distribution
losses by regulating the voltage at the SENSE pin. The
voltage between the SENSE pin and VOUT pin must not
exceed 0.5V. Note that the output voltage of the module
cannot exceed the specified maximum value. This
includes the voltage drop between the SENSE and Vout
pins. When the Remote Sense feature is not being used,
connect the SENSE pin to the VOUT pin.