When VCCA/VCCD supply is turned off or it is not supplied, open drain output pins (OUTx) becomes High-Z and HVOUT will become low. The state would be similar to a reset state. Please refer to page 1-31 of the datasheet DS1015.
Valid state/level for VCCA/VCCD supply is above 2.8V as documented in the "Recommended Operating Conditions" of the datasheet page 1-6, operation below this level is not recommended.