ZERO-CURRENT START-UP CIRCUIT

摘要

A zero-current start-up circuit (20) for a reference circuit (22) which is initially unbiased and which has internal nodes that need to be regulated to a predetermined voltage. When the start-up circuit (20) is enabled, a switching transistor (36) is turned on which enables the reference circuit (22) to generate an internal reference current which regulates an output current to a predetermined value set by the reference circuit (22). The output current flows through a voltage drop device (40 and 42) and when the voltage level reaches a predetermined value, the start-up circuit (20) is disabled eliminating the current path.