Pisces Series, Page 1
Part No. 99-002 Rev. 4.0093003
WWW.GALAXYPWR.COM
The Pisces Series is the first high-efficiency
quarter brick
CoolConverter
TM
in the Galaxy
family of high-efficiency DC/DC converters.
Industry Standard Pinout and Footprint
Typical Efficiency
92% at 3.3V, 15A; 90% at 3.3V, 30A
No Heat Sink Required
Very Low Common-mode Noise for a
Commercial DC/DC Converter
Two-stage Input Filter
Constant Switching Frequency
Remote Sense
Single Board Design
Optional Baseplate or Low Profile Heatsink for
Improved Thermal Performance
Header with M3 Metal Inserts for Mechanical
Connection to PCB
Two Year Warranty
PISCES Series
Control Functions
Uses Patented Power Supply Control
and Architecture
Microprocessor Controlled
Primary-side Enable, Choice of Logic
Protection Features
Over Temperature Protection
Over Voltage Protection
Over Current Protection
Over/Under Input Voltage Protection
Typical Characteristics
Output Setpoint Accuracy:
1%
Load Regulation:
0.2%
Line Regulation:
0.2%
Regulation over Line, Load, and Temperature:
2%
Low Output Ripple
Output Trim
The open-frame Pisces is available with an optional
baseplate or low profile heatsink for maximum
thermal performance.
Very High Efficiency DC/DC Converter
24/48V Input, 1.5V, 1.8V, 2.0V, 2.5V, 3.3V DC, 30A Output
or 5.0V DC, 20A Output
Pisces Series, Page 2
WWW.GALAXYPWR.COM
Part No. 99-002 Rev. 4.0093003
General Specifications
Operating Temperature
-40
C to +100C
Storage Temperature
-55
C to +125C
Relative Humidity
10% to 95% RH,
Non-condensing
Vibration
2 to 9Hz, 3mm disp.,
9 to 200Hz 1g
Material Flammability
UL V-0
Weight
35 grams
MTBF
Telcordia (Bellcore)
1,600,000 hours
General Specifications
V
IN
= 48V
DC
, T
A
@25
C, 300 LFM Airflow, V
OUT
=3.3V, I
OUT
= Full Load unless otherwise noted.
Available output power depends on ambient temperature and good thermal management. (See application graphs for limits.)
Input Characteristics
Parameter
Min
Typ
Max
Units
Operating Input Voltage
36
48
75
V
DC
Input Current (Model Dependent)
5
A
Input Capacitance
4.5
F
Input Hysteresis, Low Line
2
V
DC
Output Characteristics
Regulation Over Line, Load & Temperature
98
102
%V
NOM
Voltage Ripple
20
mV
RMS
Voltage Ripple, 20MHz BW
150
mV
PP
Current Range
0
30
A
Current Limit Inception
31
37
A
Short Circuit Current, Peak (see Note below)
41
A
Output Transient Response, 50% to 75% load change, 1A/
sec
5
%V
OUT
Settling Time to
1%
300
S
Turn-on Time to 98%Vnom
35
mS
Output Overshoot at Turn-on
1
%V
OUT
Trim Range
90
110
%V
OUT
Overvoltage Protection, Latching
130
%V
OUT
Isolation
Isolation Test Voltage, Input/Output (Basic)
2000
V
DC
Isolation Resistance
10
M
Features
Overtemperature Protection, Thermal Sensor, Latching*
117
C
Switching Frequency, Fixed
200
kHz
Notes: During short circuit, converter will shut down and attempt to restart once per second. The average current during this
condition will be very low and the device can be safely left in this condition continuously. For specific output voltage
specifications, see the corresponding detailed data sheet.
*PCB less than 130
C
Approvals and Standards
UL and c-UL Recognized Component, TUV,
UL60950, CSA 22.2 No. 950, IEC/EN 60950**
EMC Characteristics:
Designed to meet emission and immunity
requirements per EN55022, CISPR 22, Class B,
and CISPR 24.
** An external fuse shall be used to comply with the
requirements.
Pisces Series, Page 3
Part No. 99-002 Rev. 4.0093003
WWW.GALAXYPWR.COM
Undervoltage Lockout
30
32
36
34
40
38
Input Voltage (V)
Input Curr
ent
Voltage
Rising
Voltage
Falling
Overvoltage Lockout
75
76
78
77
80
79
Input Voltage (V)
Input Curr
ent
Voltage
Rising
Voltage
Falling
CoolConverter
TM
Galaxy's proprietary CoolConverter
TM
provides:
Patented single-stage power conversion architecture,
control, and magnetic design allow unprecedented power
density and efficiency in an isolated power supply.
An advanced microcontroller reduces parts count while
adding features, performance, and flexibility in the design.
Low common-mode noise as a result of lower capacitance
in the transformer compared to planar magnetics and
metal baseplate designs.
Higher reliability than planar transformer designs that can
suffer from via fatigue from thermal cycling, and metal
baseplate designs with board to board interconnects that
are subject to mechanical stress on electrical connections.
Protection and Control
Valid Input Voltage Range:
The converter measures the input voltage and will not
allow operation outside of the input voltage
specification. As shown by the graphs, hysteresis is
added to both the high and low voltage to prevent the
converter from turning on and off repeatedly when the
voltage is held near either voltage extreme. At low line
this assures the maximum input current is not exceeded;
at high line this assures the semiconductor devices in
the converter are not damaged by excessive voltage
stress.
ON/OFF Logic Option:
The ON/OFF control logic can be either Negative
(standard) or Positive to enable the converter. For
Negative logic, the ON/OFF pin is brought below 1.0 V
with respect to the INPUT pin to enable the converter.
The pull down must be able to sink 100
A. For
Positive logic, the ON/OFF pin is brought to greater
than 4.0V with respect to the INPUT pin and be
limited to less than 10V. To request the Positive logic
version, add the suffix (P) to the standard part number.
The ON/OFF pin has a built-in pull up resistor of
approximately 100k
to +5V.
Application Notes
Pisces Series, Page 4
WWW.GALAXYPWR.COM
Part No. 99-002 Rev. 4.0093003
Trim-down (%)
Trim-down
Output Over Voltage Protection:
The output voltage is constantly monitored by the
microprocessor and a redundant secondary-side crowbar
circuit that is set to a higher trip point than the
microprocessor protection. If the output voltage
exceeds the over-voltage specification, the
microprocessor will latch the converter off. To turn the
converter on requires either cycling the ON/OFF pin or
power to the converter. This advanced feature prevents
the converter from damaging the load if there is a
converter failure or application error. If non-latching is
required, consult factory.
Thermal Shutdown:
The printed circuit board temperature is measured
using a semiconductor sensor. If the maximum rated
temperature is exceeded, the converter is latched off.
To re-enable the converter requires cycling the ON/OFF
pin or power to the converter. If non-latching is
required, consult factory.
Control Options:
As the behavior of the circuit is determined by
firmware in the microcontroller, specific customer
requirements such as
non-latching thermal protection
custom valid input voltage range
controlled delay from initiating an ON/OFF
signal for power sequencing
can be accomplished with no change to hardware.
The standard behavior was chosen based on system
design experience but we understand that customers
often have their own requirements.
Please consult Galaxy Power for your special needs.
Remote Sense:
The output voltage is regulated at the point where the
sense pins connect to the power output pins. Total
sense compensation should not exceed 0.4V or 10% of
Vout, whichever is greater.
Safety:
An external input fuse must always be used to meet
these safety requirements.
Trim:
To trim the output voltage higher, connect the
required trim resistor from the Trim pin to the +Sense
pin. To trim the output voltage lower, connect the
required trim resistor from the Trim pin to the Sense
pin. See diagram below.
Application Notes
External Output Trimming
Trim-up (for 3.3V)
R
TRIM-UP
=
Vo (100+
%)
-
(100+
2%)
5.11k
1.225%
%
{
}
R
TRIM-DOWN
=
100
2
5.11k
%
{ }
+ Sense
Trim
Sense
Pisces Series, Page 5
Part No. 99-002 Rev. 4.0093003
WWW.GALAXYPWR.COM
GHPW3V330 Operation
Efficiency
94
92
90
88
86
84
82
80
0
10
20
30
25
Output Current (A)
Ef
ficiency (%)
36V Vin
48V Vin
75V Vin
15
5
Power Dissipation
14
12
10
8
6
4
2
0
0
10
20
25
30
Load Current (A)
Power Dissipation (W)
36V Vin
48V Vin
75V Vin
5
15
Transient Response
V
OUT
20
I
OUT
10
Voltage Ripple
V
OUT
Output Voltage vs Line Load
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
28
32
36
42
40
38
Output Current (A)
Output V
oltage (V)
36V Vin
48V Vin
75V Vin
34
30
2
1
Ch1
5.00V
Ch2 1.00 V
M 4.00ms A Ch1 2.40V
T
T
[
]
Start-up Waveform w/No Load
V
OUT
ON/OFF
Thermal Derating Curves
Ambient Air Temperature (deg C)
20
30
40
50
60
70
80
35
30
25
20
15
10
5
0
Iout (A)
300 LFM, Low Profile Heat Sink
300 LFM, Metal Plate
200 LFM, Low Profile Heat Sink
300 LFM, Open Frame
200 LFM, Metal Plate
200 LFM, Open Frame
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