GE Data Sheet
QHHD019A0B Series: DC-DC Converter Power Module
18 to 75Vdc Input; 12Vdc, 19A, 225W Output
November 20, 2019 ©2016 General Electric Company. All rights reserved. Page 7
Feature Description
Remote On/Off
Negative logic remote on/off, device code suffix “1”, turns the
module off during a logic high and on during a logic low.
ON/OFF
Vin+
Vin-
Ion/off
Von/off
Vout+
TRIM
Vout-
Figure 10. Circuit configuration for using Remote On/Off
Implementation.
To turn the power module on and off, the user must supply a
switch (open collector or equivalent) to control the voltage
(Von/off) between the ON/OFF terminal and the VIN(-) terminal.
Logic low is 0V ≤ Von/off ≤ 0.6V. The maximum Ion/off during a
logic low is 0.15mA, the switch should be maintain a logic low
level whilst sinking this current.
During a logic high, the typical Von/off generated by the module
is 5V, and the maximum allowable leakage current at Von/off =
5V is 1μA.
If not using the remote on/off feature:
For negative logic, short the ON/OFF pin to VIN(-).
Remote Sense
Remote sense minimizes the effects of distribution losses by
regulating the voltage at the remote-sense connections (See
Figure 11). The voltage between the remote-sense pins and the
output terminals must not exceed the output voltage sense
range given in the Feature Specifications table:
[VO(+) – VO(–)] – [SENSE(+) – SENSE(–)] 0.5 V
Although the output voltage can be increased by both the
remote sense and by the trim, the maximum increase for the
output voltage is not the sum of both. The maximum increase
is the larger of either the remote sense or the trim.
The amount of power delivered by the module is defined as the
voltage at the output terminals multiplied by the output
current. When using remote sense and trim, the output voltage
of the module can be increased, which at the same output
current would increase the power output of the module. Care
should be taken to ensure that the maximum output power of
the module remains at or below the maximum rated power
(Maximum rated power = Vo,set x Io,max).
Figure 11. Circuit Configuration for remote sense.
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. If the unit is
not configured with auto–restart, then it will latch off following
the over current condition. The module can be restarted by
cycling the dc input power for at least one second or by
toggling the remote on/off signal for at least one second.
If the unit is configured with the auto-restart option (4), it will
remain in the hiccup mode as long as the overcurrent
condition exists; it operates normally, once the output current
is brought back into its specified range. The average output
current during hiccup is 10% IO, max.
Overtemperature Protection
To provide protection under certain fault conditions, the unit is
equipped with a thermal shutdown circuit. The unit will
shutdown if the thermal reference point Tref (Figure 13),
exceeds 135oC (typical), but the thermal shutdown is not
intended as a guarantee that the unit will survive temperatures
beyond its rating. The module will automatically restart upon
cool-down to a safe temperature.
Input Undervoltage Lockout
At input voltages below the input undervoltage lockout limit,
the module operation is disabled. The module will only begin to
operate once the input voltage is raised above the
undervoltage lockout turn-on threshold, VUV/ON.
Once operating, the module will continue to operate until the
input voltage is taken below the undervoltage turn-off
threshold, VUV/OFF.
Output Over Voltage Protection
The output over voltage protection scheme of the modules has
an independent over voltage loop to prevent single point of
failure. This protection feature latches in the event of over
voltage across the output. Cycling the on/off pin or input
voltage resets the latching protection feature. If the auto-
VO(+)
SENSE(+)
SENSE( –)
VO(–)
VI(+)
VI(-)
IOLOAD
CONTACT AND
DISTRIBUTION LOSSES
SUPPLY II
CONTACT
RESISTANCE