| 摘要 |
A microcircuit includes core and other portions, which receive different supply voltages from disparate sources. An electrostatic discharge protection (ESD) circuit internally connects the lower and higher voltage terminals together with a diode, poled so that the diode conducts if the nominally lower voltage supply exceeds the higher voltage supply. If the high voltage supply fails or even drops below the value of the low voltage supply, the diode conducts, and current is drawn in an amount which may overheat the microcircuit. A shut-down circuit is provided for sensing the voltage of the higher-voltage source, and shutting down the lower-voltage source any time the higher-voltage source drops below either the actual voltage or nominal voltage of the lower value source.
|
