Substrate bias generator with power supply control means to sequence application of bias and power to prevent CMOS SCR latch-up
 A bias generator circuit includes a first high voltage for biasing a N-well region and a second delayed and lower voltage biasing a source region of a P-channel field-effect transistor so as to increase latch-up immunity. The generator circuit includes a high voltage generator and a multiplier circuit responsive to a power supply voltage for generating a first voltage level for biasing the N-well region. A delay network is responsive to the first voltage for generating a delay voltage. A level detection circuit is responsive to the delay voltage and the power supply voltage for generating a control signal when the delayed voltage reaches a predetermined level. A control device is responsive to the control signal for generating a second voltage for biasing the source region of the P-channel field-effect transistor. The second voltage level is delayed and lower than the first voltage level so that the PN junction is reverse biased to increase latch-up immunity. 
Advanced Micro Devices, Inc.
H G
H01L G05F
inventional inventional
Wei-Ti
Liu