Bootstrap Driver Circuit Having Voltage-Controlled Breakdown Protection
Original Publication Date: 1985-Jan-01
Included in the Prior Art Database: 2005-Feb-18
Improved performance is obtained in a bootstrap FET clock driver circuit by the use of a control signal on the gate of a bootstrapped node discharging device, commonly known as a totem-pole device. In this circuit the gate of the totem-pole device is momentarily discharged during the time the bootstrapped voltage node is being boosted in order to isolate parasitic voltage nodes to reduce the time required to increase the voltage on the pre-charged bootstrap voltage node. Fig. 1 shows a simplified version of the circuit. Device T7 is the totem-pole device and normally has the supply voltage V applied to its gate electrode. The purpose of T7 is to prevent discharging device T9 from breaking down when its gate and source voltages are zero volts and it drain voltage is boosted higher than drain supply voltage V.