Some embodiments include apparatus and methods having a first node to receive a supply voltage, a second node to receive a first bias voltage, a third node to receive ground potential, a first circuit branch coupled between the first and second nodes, and a second circuit branch coupled between the first and third nodes. The first bias voltage is provided to a gate of a first transistor among a plurality of transistors coupled in series. The first and second circuit branches are arranged to provide a second bias voltage to gate of a second transistor among the plurality of transistors. The value of the second bias voltage is based on a value of the first bias voltage.