Cross-Coupled Cmos Substrate Voltage Generator
Original Publication Date: 1986-May-01
Included in the Prior Art Database: 2005-Mar-09
Two charge pumps, 180 degrees out of phase, are used with each other, to pump current out of the substrate to ground. Each charge pump is connected to the substrate through a transistor, whose gate is connected to the other charge pump. The result is that instead of drawing current from the substrate through a parasitic diode, current is drawn through a turned-on transistor. This eliminates minority current carrier injection to the substrate (a possible cause of latch-up and erasure of dynamic RAM (random-access memory) data), and increases charge pump efficiency by removing the .7-volt drop across a parasitic diode.