Application Notes
Signal Characteristics:
Per table on page 5.
Input Signals:
Enable_L:
This input signal is used to enable the
output of the converter when activated (active Low).
The signal is referenced to the output side (–Sense).
Enable_L does not require an external pull-up resistor.
If an external pull-up is used it should be tied to +5V.
To minimize start-up problems it is recommended that
Enable_L be driven from an open-drain configured FET.
Voltage Adjust:
The output voltage of the converter
shall be adjustable as specified in the table on page 3.
The voltage adjust pin sources 1 mA current. The
adjustment shall be done using an external voltage
source or a resistor connected between the Voltage
Adjust pin and the – Sense pin. See below for output
voltage adjustment application information.
Current Share:
When two or more converters are
connected in parallel, their current share pins must be
connected together to allow proper load sharing.
Sync:
When two or more converters from the same
manufacturer are connected in parallel, their sync pins
may be connected together to synchronize their
operating frequencies. When two or more converters
from different manufacturers are connected in parallel
their sync pins must NOT be connected together.
Output Signals:
MODOK_L:
MODOK_L shall be asserted to indicate
that the output voltage is in regulation. When two or
more converters are operating in parallel a failed
converter may or may not de-assert its MODOK_L
signal.
OTW_L:
OTW_L shall be asserted to indicate that the
converter temperature is too high and that the converter
is about to shut down. OTW_L will be asserted a
minimum of 500 msec before the converter shuts down
due to an overtemperature condition. The output of this
signal is the open drain of a FET. The output is current
limited to 8-15 mA and may be used to drive an external
LED directly.
Output Voltage Adjustment:
Voltage Programming:
A voltage may be applied
between the Voltage Adjust pin (pin 5) and the – Sense
pin (pin 1) to adjust the output voltage up or down from
the nominal output voltage by a maximum of
±10%.
The trim voltage for the GPH1V5-40 and GPH1V5-60
is:
(V
O
– 1.5)
V
TRIM
= —————— + 1.0V
0.30
For the GPH2V2-40 and GPH2V2-60 the output voltage
may be trimmed to +15% , - 10%. The trim voltage for
these two units is:
V
TRIM
(V
O
– 2.2)
= —————— + 1.0V
0.44
The trim voltage for the GPH3V3-40 and GPH3V3-60 is:
(V
O
– 3.3)
V
TRIM
= —————— + 1.0V
0.66
The trim voltage for the GPH5V0-30 and GPH5V0-40
is:
(V
O
– 5.0)
V
TRIM
= —————— + 1.0V
1.0
Resistor Programming:
A resistor may be connected
between the Voltage Adjust pin (pin 5) and the
– SENSE pin (pin 1) to adjust the output voltage up or
down from the nominal output voltage by a maximum
of +/- 10 %. The GPH2V2-40, -60 may be adjusted
+15 %, -10 %. The value of the trim resistor is for a
single converter or for multiple paralleled converters
with separate trim resistors on each of their Voltage
Adjust pins.
Although not recommended, the Voltage Adjust pins for
N paralleled converters may be tied together. In this
case the value of the trim resistor will be R
TRIM
/N.
For the GPH1V5-40 and GPH1V5-60, the trim resistor
value in Kohms for these two units is:
(V
O
– 1.5)
R
TRIM
= —————— + 1.0KΩ
0.30
The resistor value in Kohms for the GPH2V2-40 and
GPH2V2-60 is:
(V
O
– 2.2)
R
TRIM
= —————— + 1.0KΩ
0.44
The resistor value in Kohms for the GPH3V3-40 and
GPH3V3-60 is:
(V
O
– 3.3)
R
TRIM
= —————— + 1.0KΩ
0.66
Hercules Series, Page 6
WWW.GALAXYPWR.COM
Part No. 98–002 Rev. 1.1
GALAXY [ GALAXY POWER, INC. ]
