A reduced cost voltage regulation circuit for switched mode power supplies. In
one embodiment, a voltage regulation circuit includes a current sense circuit having
a current sense terminal to conduct a current to be sensed by the current sense
circuit. A voltage difference between the current sense terminal and a voltage
reference terminal is substantially fixed when the current to be sensed by the
current sense circuit is substantially equal to a first current sense threshold.
The voltage regulation circuit also includes a first impedance coupled between
the current sense terminal and the voltage reference terminal to provide a second
current sense threshold. The second current sense threshold is equal to a sum of
the first current sense threshold and a current to flow through the first impedance.
The voltage regulation circuit further includes a second impedance coupled between
the current sense terminal and an input terminal. The input terminal has a voltage
threshold relative to the voltage reference terminal that is different from a voltage
at the current sense terminal by an amount that is a product of the second impedance
and the second current threshold.