Application Notes

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Figure 3-2

Figure 3-3

Vo (2 V/Div)

Iin (1 A/Div)

Vinh (10 V/Div)

HORIZ SCALE: 5 ms/Div

Power-Up Characteristics

When configured per the standard application, the

PTH12000x power modules produce a regulated out-

put voltage whenever of a valid input voltage is applied

the power-up period, internal soft-start circuitry slows the

rate that the output voltage rises. This reduces the in-rush

current drawn from the input source. The soft-start cir-

cuitry also introduces a short time delay (typically 12 ms)

into the power-up characteristic. The delay is from the

point that a valid input source is recognized, to the initial

rise of the output voltage. Figure 3-1 shows the power-

up characteristic of the PTH12000W with the output

voltage set to 5-V. The waveforms were measured with a

2-A resistive load. The initial rise in input current when

the input voltage first starts to rise is the charge current

drawn by the input capacitors.

Figure 3-1

Vin (5 V/Div)

Vo (5 V/Div)

Iin (2 A/Div)

HORIZ SCALE: 5 ms/Div

Over-Current Protection

For protectection against load faults, this series incorpo-

rates output over-current protection. Applying a load that

exceeds the module’s over-current threshold will cause

the regulated output to shut down. Following shut down

the module will periodically attempt to recover by initi-

ating a soft-start power-up. This is often described as a

“hiccup” mode of operation, whereby the module con-

tinues in the cycle of successive shut down and power up

until the load fault is removed. During this period, the

average current flowing into the fault is significantly

reduced. Once the fault is removed, the module auto-

matically recovers and returns to normal operation.

Output On/Off Inhibit

The inhibit control (pin 3) is used wherever there is a

requirement to turn off the regulator output while input

power is applied.

PTH12000 Series

PTH12000W

4

5

2

3

L

O

A

D

100 µF

100 µF

1 =Inhibit

GND

GND

BSS138

280

1%

1

The power modules function normally when the Inhibit

pin is left open-circuit, providing a regulated output

respect to GND.

Figure 3-2 shows the typical application of the inhibit

open-collector or open-drain device is recommended to

control this input.

off, the module will execute a soft-start power-up. A

regulated output voltage is produced within 25 msec.

Figure 3-3 shows the typical rise in both the output volt-

and 2-A resistive load.