LB1941GP Datasheet, PDF (4/4 Pages) Sanyo Semicon Device – Monolithic Linear IC For Digital Cameras Constant Current Forward/Reverse Driver

Truth Table
Input
IN1
IN2
L
L
H
L
L
H
H
H
Output
OUT1
OUT2
OFF
OFF
H
L
L
H
OFF
OFF
LB1941GP
Mode
Standby 1*
Forward rotation
Reverse rotation
Standby 2*
Cautions for use
Standby states 1 and 2 in the above truth table differ as follows:
Standby state 1 ............All circuits in IC are not operating and the current dissipation is almost zero.
Standby state 2 ............The constant-current control amplifier output in IC is in the full drive condition. Both OUT1
and OUT2 are OFF. The current dissipation is a few mA.
During mode transfer from the standby state 1 to forward (reverse) rotation, the current rises from the output current
zero condition to the required constant current value. On the other hand, during mode transfer from the standby state
2 to forward (reverse) rotation, full drive is applied once to the output, then the current lowers to the required current
value.
Therefore, select the standby 1 state when putting IC in the standby state. A typical drive sequence is shown in the
figure below.
Reverserotation
Standby
Fowardrotation Reverserotation Standby
IN1
IN2
Boost charge and discharge circuits
In order to keep the output response time constant during mode transfer from the standby state to forward (reverse)
rotation, this IC incorporates boost charge and discharge circuits for external capacitor connected to the FC pin.
The external capacitor connected to the FC pin is for output phase compensation (to suppress oscillation), for which
0.01 to 0.1µF is recommended. Note that increase in the capacitor value results in increase in the time necessary for
the constant current control to rise.
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PS No.A0195-4/4