An open write head detection circuit is provided comprising a write head driver
circuit, a programmable reference voltage source, a comparator and a pulse width
filter. The write head driver circuit generates an voltage sense signal. The comparator
compares the voltage sense signal with a reference voltage from the programmable
reference voltage source and generates a comparator output signal indicative of
whether the voltage sense signal is greater than or less than the reference voltage.
The comparator output signal is input to the pulse width filter which generates
a latched open head signal in response the voltage sense signal being less than
the reference level for a predetermined time measured as a programmable number
of write clock cycles.