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Datasheet Version 1.1

Mar. 2015. Revision 1.1

MagnaChip Semiconductor Ltd.

10

Applications

Under-voltage Lockout

all the rails will restart with soft-start when input voltage is applied again

ENP/ENN

The ENP pin controls the output of VPOS and the ENN pin controls the output of VNEG. A high on either ENP

or ENN will enable the boost converter VREG. VPOS, VNEG and VREG require both their respective EN pin high

for each to be enabled

Power On / Off Sequence

The VREG boost regulator is activated when the input voltage is higher than the UVLO threshold, and either ENP

or ENN are high. The VPOS output is activated if ENP is high and VREG has completed its soft-start. The VNEG

output is activated if ENN is high and VREG has completed its soft-start.

ENP or ENN being pulled low shuts down VPOS or VNEG, respectively. If both ENP and ENN are pulled low,

VPOS, VNEG and VREG are all turned off

The discharge resistors of the VPOS and VNEG output are 70

Ω and 20Ω respectively.

VIN

ENP

ENN

VREG

VREG power good

VPOS

VNEG

UVLO

0.7ms

0.7ms

0.7ms

VIN

ENP

ENN

VREG

VREG power good

VPOS

VNEG

UVLO

0.7ms

0.7ms

0.7ms

Figure 18: Example of power on sequence when ENN

Figure 19: Example of power on sequence when both ENP

rising after VPOS soft-start finished

and ENN rising before VREG soft-start finished