SQ60120QZB40 Datasheet, PDF (11/14 Pages) –

Application Section
Input:36-75V
Output:12V
Current:40A
Part No.:SQ60120QZB40
Protection Features
Input Under-Voltage Lockout: The converter is designed
to turn off when the input voltage is too low, helping avoid
an input system instability problem, described in more detail
in the application note titled “Input System Instability”
available on www.SynQor.com. The lockout circuitry is a
comparator with DC hysteresis. When the input voltage is
rising, it must exceed the typical Turn-On Voltage Threshold
value (listed on the specification page) before the converter
will turn on. Once the converter is on, the input voltage
must fall below the typical Turn-Off Voltage Threshold value
before the converter will turn off. Also see Fig E.
Output Current Limit: The output of the BusQor module
is electronically protected against output overloads. When
an overload current greater than the DC Current-Limit
Inception specification is drawn from the output, the output
of the BusQor will shutdown to zero volts after the 1ms
have elapsed (see Fig C). The shutdown period lasts for
a typical period of 200ms (Fig D) after which the BusQor
tries to power up again. If the overload persists, the output
voltage will go through repeated cycles of shutdown and
restart with a duty cycle of 20ms (On) and 200ms (Off)
respectively. The BusQor module returns (auto resetting)
to normal operation once the overload is removed. The
BusQor is designed to survive in this mode indefinitely
without damage and without human intervention.
Output Short Circuit Protection: When the output of
the BusQor module is shorted, a peak current of typically 35A
will flow into the short circuit for a time of about 1ms. The
output of the BusQor will shutdown to zero volts after the
1ms have elapsed (Fig C & D). The shutdown period lasts
for a time of 200ms, at the end of which the BusQor module
tries to power up again. If the short circuit persists, the
output voltage will go through repeated cycles of shutdown
and restart with a duty cycle of 20ms (On) and 200ms (Off)
respectively. The BusQor module returns (auto resetting)
to normal operation once the short circuit is removed. The
BusQor is designed to survive in this mode indefinitely
without damage and without human intervention.
In the Auto resetting mode, also referred to as “Hiccup”
mode, the power drawn from the 48V input is about 5W,
most of which is dissipated into the external fault. It is
important that copper traces and pads from the output
circuit be designed to withstand the short term peaks,
although the average current into the fault may be as low
as 50mA typical. See Fig 17 for appropriate waveform.
Over-Temperature Shutdown: A temperature sensor
on the converter senses the average temperature of the
module. The thermal shutdown circuit is designed to turn
the converter off when the temperature at the sensed
location reaches the Over-Temperature Shutdown value.
It will allow the converter to turn on again when the
temperature of the sensed location falls by the amount of
the Over-Temperature Shutdown Restart Hysteresis value.
Output
Current
60A
40A
Output
Voltage
12V
0V
1ms
Time
Figure C: Output Overload protection diagram (not to scale)
Output
Current
80A
pea^Pk^eak
Output
Voltage
<_<1₁2₂V_V
0V
Time
Shutdown
2_P0_e0_rm_iods
Duty
20_Cm_ys_cle
Figure D: Output Short Circuit and Auto-Resetting protection diagram (not to scale)
Product # SQ60120QZB40
Phone [phone]
www.synqor.com
Doc.# 005-0006404 Rev. 4
07/30/2015
Page 11