BQ50120QTA20 SYNQOR [SynQor Worldwide Headquarters], BQ50120QTA20 Datasheet - Page 9

• Manufacturer Part Number: BQ50120QTA20
• Description: Quarter-brick DC Bus Converter
• Manufacturer: SYNQOR [SynQor Worldwide Headquarters]

Product # BQ50120QTA20
T
T
Output Current Limit: The output of the BusQor module is
electronically protected against output overloads. When an over-
load current greater than the “DC Current-Limit Inception” speci-
fication is drawn from the output, the output shuts down to zero
volt in a period of 40µs typical (see Figure C). The shutdown
period lasts for a typical period of 250ms (Figure 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 40µs (On) and 250ms (Off) respec-
tively. The BusQor module returns (auto resetting) to normal oper-
ation 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 40 A will
flow into the short circuit for a period of about 300µs. The out-
put of the BusQor will shutdown to zero volts for the same period
(Figure D). The shutdown period lasts for a period of 250ms, at
the end of which the BusQor module tries to power up again. If
Figure D: Output Short Circuit and Auto-Resetting protection
Figure C: Output Overload protection diagram
echnical S
echnical S
Current
Voltage
Output
Output
<12V
Current
Voltage
Output
Output
0V
12V
0V
diagram
250ms
(not to scale)
pecification
pecification
Phone [phone]
40µs
300µs
25A
20A
Time
Time
(not to scale)
40A peak
www.synqor.com
the short circuit persists, the output voltage will go through repeat-
ed cycles of shutdown and restart with a duty cycle of 350µs
(On) and 250ms (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 indef-
initely 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 5 Watts, most of
which is dissipated into the external fault. It is important that cop-
per traces and pads from the output circuit be designed to with-
stand the short term peaks, although the average current into the
fault may be as low as 50mA typical. See Figure 17 for appro-
priate 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.
APPLICATION CONSIDERATIONS
Start-Up Inhibit Period: Figure E details the Start-Up Inhibit
Period for the BusQor module. At time t
with On/Off pin asserted (enabled), the BusQor output begins to
build up. Before time t
threshold, the unit is disabled by the Input Under-Voltage Lockout
feature. When the input voltage rises above the UVL threshold,
the Input Under-Voltage Lockout is released, and a typical Startup
Inhibit Period of 350µs is initiated. The output builds up to 90%
or higher of the nominal voltage and stabilizes at the nominal
value of 12V in a period of 420µs typical. The rise time from 0V
to 90% is 70µs typical.
At time t
BusQor output instantly drops to 0V. Fall time from 12V to 0V is
dependent on output capacitance and any parasitic trace induc-
tance in the output load circuit.
At time t
BusQor module output begins to build up after the inhibit period
of 350µs typical.
Refer to the Control Features section of the data sheet for details
on enabling and disabling methods for N and P logic type mod-
ules.
2
3
Doc.# 005-2BQ512J Rev. E
, when the On/Off pin is de-asserted (disabled), the
, when the On/Off pin is re-asserted (enabled), the
1
, when the input voltage is below the UVL
P
P
Current:
Current:
ackage:
ackage:
Output:
Output:
Input:
Input:
03/17/06
0
42-53 V
12 V
20 A
Quarter-brick
42-53 V
12 V
20 A
Quarter-brick
, when Vin is applied
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