  We present the results of the X-ray flaring activity of 1ES 1959+650 during
October 25-26, 2017 using AstroSat observations. The source was variable in the
X-ray. We investigated the evolution of the X-ray spectral properties of the
source by dividing the total observation period ($\sim 130$ ksecs) into time
segments of 5 ksecs, and fitting the SXT and LAXPC spectra for each segment.
Synchrotron emission of a broken power-law particle density model provided a
better fit than the log-parabola one. The X-ray flux and the normalised
particle density at an energy less than the break one, were found to
anti-correlate with the index before the break. However, a stronger correlation
between the density and index was obtained when a delay of $\sim 60$ ksec was
introduced. The amplitude of the normalised particle density variation $|\Delta
n_\gamma/n_\gamma| \sim 0.1$ was found to be less than that of the index
$\Delta \Gamma \sim 0.5$. We model the amplitudes and the time delay in a
scenario where the particle acceleration time-scale varies on a time-scale
comparable to itself. In this framework, the rest frame acceleration time-scale
is estimated to be $\sim 1.97\times10^{5}$ secs and the emission region size to
be $\sim 6.73\times 10^{15}$ cms.
