  We present an inexpensive, low-noise ($<260~\mu$V$_{rms}$, 0.1~Hz - 100~kHz)
design for a piezo driver suitable for frequency tuning of external-cavity
diode lasers. This simple driver improves upon many commercially available
drivers by incorporating circuitry to produce a `feed-forward' signal
appropriate for making simultaneous adjustments to the piezo voltage and laser
current, enabling dramatic improvements in mode-hop-free laser frequency tuning
range. We present the theory behind our driver's operation, characterize its
output noise, and demonstrate its use in absorption spectroscopy on the
rubidium D$_1$ line.
