  We investigate the charged Higgs boson signal at the LHC using its dominant
production and decay modes with triple b-tagging, i.e. $tH^- \to t\bar tb \to
b\bar bb W^+ W^-$, followed by leptonic decay of one W and hadronic decay of
the other. We consider the continuum background from the associated production
of $t\bar t$ with a b- or a light quark or gluon jet, which can be mis-tagged
as b-jet. We reconstruct the top quark masses to identify the 3rd b-jet
accompanying the $t\bar t$ pair, and use its p_T distribution to distinguish
the signal from the background. Combining this with the reconstruction of the
$H^\pm$ mass gives a viable signature over two interesting regions of the
parameter space - i.e. $\tan\beta \sim 1$ and $\sim m_t/m_b$.
