Technical Note

11/15

www.rohm.com

2011.05 - Rev.B

© 2011 ROHM Co., Ltd. All rights reserved.

BD6062GU

7) Soft start

BD6062GU has soft start function.

Soft start function will prevent the big peak current from IC and coil.

The detail of soft start is as follows.

Fig.32 Soft start Diagram and Timing

8) Soft Current Limiter

BD6062GU has Soft Current Limiter function.

Soft current limiter function will change the value of current gradually.

It has four steps. And the steps are as follows;

4Step of soft current limiter

Action

Start

2nd step

3rd step

4th step

Normal

Time

0~500us

500~700us

700~800us

800~900us

900us~

Current Limit

(DC)

0A* always

0.5A

1A

1.5A

2A

Current Limit “H (peak)

1.125A

1.75A

2.375A

3.0A

3.625A

Current Limit “L (peak)

0.675A

1.05A

1.425A

1.8A

2.175A

Peak current of BD6062GU depends on only soft current limiter.

Switching frequency or VBAT voltage does not affect Peak current of BD6062GU.

9) Thermal shut down

BD6062GU has a thermal shut down function.

It works above 175℃, and while, IC will change the status from active to inactive.

When the temperature will be under 175℃, IC will return to normal operation.

EN

VOUT

A

B (dashed)

C

duty width increase little by little

Q

B

C

S

RQ

Q

OSC

PGND

ERRAMP

L

SW

VOUT

A