APPLICATION NOTES
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 shutdown 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.
R
TRIM-DOWN
=
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.
Trim-down
Trim-down (%)
{
100
– 2 kΩ
∆%
}
Trim-up (for 3.3V)
Trim-up (%)
R
TRIM-UP
=
{
Vo (100+∆%) (100+2∆%)
–
1.225∆%
∆%
}
kΩ
External Output Trimming
+ Sense
Trim
– Sense
Taurus Series, Page 4
WWW.GALAXYPWR.COM
Part No. 99–001 Rev. 5.0–090803
GALAXY [ GALAXY POWER, INC. ]
