  We discuss a model for the central region of radio-quiet AGN in which coronal
accretion is the source of energy for X-ray emission. We start from the Haardt
& Maraschi model but supplement it with pressure balance condition, two
possibilities of the angular momentum transfer and three models of the
disc-corona transition. We employ the alpha-description of viscosity within the
two layers. Both descriptions of the angular momentum transport lead to similar
conclusions about the fraction of energy liberated in the disc although they
predict strongly different properties of the disc interiors. The coupled
disc/corona system has one family of solutions at low accretion rates, two
families of solutions at intermediate accretion rates and no solution for high
accretion rate. Of the two families of solutions, the first one has weakly
dissipating coronae and the second one has coronae which dominate energetically
the system. The two solutions merge at sub-Eddington accretion rate because a
corona in hydrostatic equilibrium can dissipate only a limited amount of
energy, which depends on the viscosity parameter.
