We present a construction of boundary states based on the Coulomb-gas
formalism of Dotsenko and Fateev. It is shown that Neumann-like coherent states
on the charged bosonic Fock space provide a set of boundary states with
consistent modular properties. Such coherent states are characterised by the
boundary charges, which are related to the number of bulk screening operators
through the charge neutrality condition. We illustrate this using the Ising
model as an example, and show that all of its known consistent boundary states
are reproduced in our formalism. This method applies to c<1 minimal conformal
theories and provides an unified computational tool for studying boundary
states of such theories.Comment: 10 pages, 1 figure, revtex. Minor corrections, references added. To
appear in Nuclear Physics