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dc2116afa

DEMO MANUAL DC2116A

Dc2116a-a Quick start proceDure

Dc2116a-B Quick start proceDure

Turn on the power supply; verify the input voltage is 12V.

Verify the output voltage and the load current; D3 and D4

should both be illuminated (input voltage and output volt-

age,respectively)andbothD1(FLT)andD2(PG)shouldbe

be in the range of 0.15 to 0.55V/ms, corresponding to a

ramp-up time of 22ms to 80ms to 12V. With the circuit

functioning,additionalevaluationscannowbeperformed.

OV/UV/PG thresholds – Set the input supply to zero and

ramp the voltage slowly, observing the following events.

Above 10.0V, the circuit will be out of UV lockout and the

output should ramp up, lighting D4. Above 10.9V the FB

pin will be past its threshold, asserting the PG pin high and

extinguishing D2. Increasing the supply past 15.2V will

engage OV lockout; D4 will extinguish and D2 will light.

Notethatthevoltagesindicatedinthissteparemaximums,

taking into consideration the tolerances of the resistors

and the LTC4234 thresholds.

Current Limit Thresholds – With the input supply set to

12V,loadtheoutputwitha0.59Ωpowerresistorcapableof

dissipating 300W. Power should remain on, as the current

will be below the 20A minimum current limit threshold.

Next, load the output with a 0.48Ω power resistor. Power

should be interrupted, as the current will be above the 25A

maximum current limit threshold.

Inrush into capacitive load – One of the main functions of

a Hot Swap circuit is to provide controlled ramp-up into a

capacitive load to avoid disturbing the input power sup-

ply. For the following tests, ensure that the AUTORETRY

jumper is set to OFF and the TIMER DURATION jumper

is set to 2.0ms. To guarantee that current limit is never

reached during ramp-up into a capacitor, the current must

be less than the minimum current limit threshold of 4A

when the gate ramp rate is at its maximum value of 0.6V/

ms.(Notethattheminimumcurrentlimitthresholdoccurs

when the FB pin is at 0V.)

C = i/(dV/dt) = 4A/(0.6V/ms) = 6667µF

Thus the circuit will always power up successfully with a

turret post will show that it never begins to ramp.

The LTC4233, on the DC2116A-B, should be tested as

above with actual values scaled to values shown in the

data sheet.