ACT6390/ACT6391

Rev 1, 22-Aug-13

- 8 -

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Copyright © 2013 Active-Semi, Inc.

Rectifier Selection

For optimal performance, the rectifier should be a

Schottky rectifier that is rated to handle both the

output voltage as well as the peak switch current.

Over Voltage Protection

The ACT6390 and ACT6391 both feature internal

automatic over-voltage protection (OVP). Once the

outputs achieve regulation, if the voltage at FB falls

below 0.125V the controller will automatically dis-

able and latch off, preventing the controller from

running open-loop and potentially damaging the IC

and load.

To re-enable the converters, simply cycle the EN

pin or remove and reapply power to the input.

Shutdown

Drive EN low to disable the IC and reduce the sup-

ply current to just 0.1µA. As with all non-

synchronous step-up DC/DC converters, the exter-

nal Schottky diode provides a DC path from the in-

put to the output in shutdown. As a result, the out-

put drops to one diode voltage drop below the input

in shutdown.

Thermal Shutdown

The ACT6390 and ACT6391 both feature integrated

thermal overload protection. Both devices are auto-

matically disabled when their junction temperatures

exceed 160°C, and automatically re-enable when

the die temperature decreases by 20°C.

pF

8

.

70

Ω

k

233

F

μ

33

Ω

5

.

0

R

C

R

C

COMP

OUT

ESR

2

COMP

=

×

=

×

=

()

kHz

64

.

9

Ω

5

.

0

F

μ

33

π

2

1

f

ESR

Z

=

×

×

=

(31)

(32)