Integrated circuit with improved on-chip power supply control

Abstract

An on-chip power supply regulation system for a VLSI circuit such as a dynamic RAM is disclosed. The system includes a high power supply voltage detection circuit and a power supply clamp circuit, where a clamped voltage generated by the clamp circuit biases the functional circuitry when the high power supply voltage detection circuit detects an overvoltage condition. The bias voltage applied to the functional circuitry in the normal operating condition can be a regulated voltage generated from the power supply voltage. Further included in the disclosed circuit is a burn-in voltage generation circuit and a burn-in voltage detection circuit, which can apply an accelerated voltage which depends upon the applied power supply voltage, when the power supply voltage is higher than during normal operation but lower than in the overvoltage condition enabling the clamp operation. A multiplexer connects the regulated voltage, the clamped voltage, or the accelerated voltage, to the circuit depending upon the level of the external power supply voltage. In this way, the offset between the accelerated voltage and the external power supply voltage can be optimized independently from the power supply voltage at which the accelerated voltage is enabled.