Technical Note

11/18

www.rohm.com

2010.06 - Rev.A

© 2010 ROHM Co., Ltd. All rights reserved.

BD7755RFV

6. Protect system 1

It is a function to mute the actuator outputs when the IC outputs the current more than the setting threshold value IPRTLIM

for 1.2sec because of the protection for the focus, the tracking, and the tilt coil. Outputs are muted similarly when the

output current of two or three CHs continuously exceed the threshold for 1.2sec.

It returns to normal operation by setting CTL2=L.

IPRTLIM =

A

RPRTLIM(Ω)

(A)

A = 8750

PRTFLG(OUTPUT)

Actuator output (FCO/TKO/TLO)

H

OFF

L

active

MIN.

TYP.

MAX.

Unit

Time until protection function operates

1.0

1.2

1.4

s

Current between

FCO outputs

0

Current between

TLO outputs

Current between

TKO outputs

CTL2

0

0

Low

High

FCIN1

0

Current between

FCO outputs

Current between

TLO outputs

Current between

TKO outputs

CTL2

0

FCIN1

0

0

threshold current

0

threshold current

Low

High

threshold current

threshold current

threshold current

threshold current

1.2sec

mute

1.2sec

mute

reset

7. Protect system 2

Function to protect against destruction of output terminal when output pin connects to GND or Vcc.

PRTFLG(OUTPUT)

Spindle, Sled motor driver output

H

OFF

L

active

・Spindle, Sled motor

・When SINK side POWER transistor has been turned on, if the output voltage (SPVM/2&SLVM/2<TYP> or more) are

detected, the channel concerned will be turned off.

・When SOURCE side POWER transistor has been turned on, if the output voltage (SPVM/2&SLVM/2<TYP> or less ) are

detected, the channel concerned will be turned off.