A high-output impedance, wide swing bulk-driven current source with dynamic biasing

In this paper, a high-output impedance, wide output swing bulk-driven current source with dynamic biasing is proposed. To increase the output impedance, a bulk-driven gain-boosted cascode feedback amplifier is used. Two dynamic biasing circuits are introduced: one is used to adaptively bias the gate of the current source output transistor while the other is used to supplement current into the output node when the output voltage is low. In addition, the dynamic biasing circuits help to boost the output impedance further. Simulation results show that under 0.6 V supply voltage, the minimum output voltage is below 100 mV and the output impedance is over 200 MΩ.