Low power start-up circuit for bandgap voltage reference

摘要

As a source voltage 316 increases from zero, a PMOS device 304 in a start-up circuit 300 supplies current to a node 314 of a bandgap voltage reference circuit 302. When the voltage at node 314 reaches a predetermined level, an inverter 306 switches its output towards ground, and the output of a second inverter 308 increases towards that of the source voltage 316, causing device 304 to turn off and stop the supply of current to the node 314. This reduced current requirement increases efficiency and avoids heating problems.