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HBC48T25120 Datasheet, PDF (7/16 Pages) Power-One – HBC48T25120 DC-DC Converter Data Sheet
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HBC48T25120 DC-DC Converter Data Sheet
36-75 VDC Input; 12 VDC @ 25 A Output
Startup Information (using negative ON/OFF)
Scenario #1: Initial Startup From Bulk Supply
ON/OFF function enabled, converter started via application
of VIN. See Figure E.
Time
Comments
t0
ON/OFF pin is ON; system front end power is
toggled on, VIN to converter begins to rise.
t1
VIN crosses undervoltage Lockout protection
circuit threshold; converter enabled.
t2
Converter begins to respond to turn-on
command (after 50ms turn-on delay).
t3
Converter VOUT reaches 100% of nominal value.
For this example, the total converter startup time (t3- t1) is
typically 54 ms.
Scenario #2: Initial Startup Using ON/OFF Pin
With VIN previously powered, converter started via
ON/OFF pin. See Figure F.
Time
Comments
t0
VINPUT at nominal value.
t1
Arbitrary time when ON/OFF pin is enabled
(converter enabled).
t2
End of converter turn-on delay.
t3
Converter VOUT reaches 100% of nominal value.
For this example, the total converter startup time (t3- t1) is
typically 4 ms.
Scenario #3: Turn-off and Restart Using ON/OFF Pin
With VIN previously powered, converter is disabled and
then enabled via ON/OFF pin. See Figure G.
Time
Comments
t0
VIN and VOUT are at nominal values; ON/OFF pin
ON.
t1
ON/OFF pin arbitrarily disabled; converter output
falls to zero; turn-on inhibit delay period (200 ms
typical) is initiated, and ON/OFF pin action is
internally inhibited.
t2
ON/OFF pin is externally re-enabled.
If (t2- t1) ≤ 200 ms, external action of
ON/OFF pin is locked out by startup inhibit
timer.
If (t2- t1) > 200 ms, ON/OFF pin action is
internally enabled.
t3
Turn-on inhibit delay period ends. If ON/OFF pin
is ON, converter begins turn-on; if off, converter
awaits ON/OFF pin ON signal; see Figure F.
t4
End of converter turn-on delay.
t5
Converter VOUT reaches 100% of nominal value.
For the condition, (t2- t1) ≤ 200 ms, the total converter
startup time (t5- t2) is typically 204 ms. For (t2- t1) > 200 ms,
startup will be typically 4 ms after release of ON/OFF pin.
MCD10127 Rev. 1.1, 09-Jun-10
Page 7 of 16
Fig. E: Startup scenario #1.
Fig. F: Startup scenario #2.
Fig. G: Startup scenario #3.
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