LB8653T, LB8653FN

No.7982-13/14

(7) Shutter drive “Regeneration” mode

The “Regeneration” (MD1/MD2/MD3/IN1/IN2 = L/L/L/H/H) in shutter mode is used to slow the coil current

decay. This mode makes coil current regenerative (Slow-Decay) within the output H-bridge by switching from

“Close” (MD1/MD2/MD3/IN1/IN2 = L/L/L/L/H). (Refer to the following figure.)

(1) “Close” (MD1/2/3/IN1/2 = L/L/L/L/H)

(2) “Regeneration” (MD1/2/3/IN1/2 = L/L/L/H/H)

When shutter control is switched from “Stand-by” to “Close” (“Open”), the current rises to the target constant-

current value from the state of output current 0 (zero). However, the output of the constant-current control

amplifier inside the IC is in the full drive state during the above-mentioned “Regeneration” state. Therefore, when

it is switched from “Regeneration” to “Close” (“Open”), the current falls to the target constant-current value from

the state of full drive output.

For that reason, to switch the shutter drive to “Close” (“Open”) from “Regeneration” by constant-current control,

it must be switched to “Stand-by” once before switching to “Close” (“Open”).

The example of drive sequence is shown in the figure below.

(8) GND wiring and each power supply line capacitor

Connect PGND and SGND near the IC and set a capacitor to the part nearest the power supply pin for each power

supply.

OUT8

OUT7

OUT8

OUT7

ILB01670

IN2

IN1

Stand-by

Close

Open

Open

Regeneration

Stand-by

ILB01671