Bias current generation systems are disclosed. In one embodiment, a bias
current generation system comprises a proportional to absolute
temperature (PTAT) current source generating a PTAT current, a constant
current source generating a constant current, a first current mirror
forwarding the PTAT current, a second current mirror forwarding an
adjusted current, where the adjusted current is the constant current
subtracted by the PTAT current if the constant current subtracted by the
PTAT current is greater than zero or the adjusted current is zero if the
constant current subtracted by the PTAT current is less than zero, a
third current mirror forwarding the adjusted current and a fourth current
mirror forwarding a bias current generated by subtracting the PTAT
current from the adjusted current.