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Bootstrap Inverter Driver

IP.com Disclosure Number: IPCOM000086214D
Original Publication Date: 1976-Aug-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Harroun, TV: AUTHOR

Abstract

The circuit is a nonclocked power inverter driver, employing -channel field-effect transistors, which drives capacitance loads with fast output pulses ranging from 0 to Vdd volts.

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Bootstrap Inverter Driver

The circuit is a nonclocked power inverter driver, employing -channel field- effect transistors, which drives capacitance loads with fast output pulses ranging from 0 to Vdd volts.

The circuit operates as a bootstrap inverter driver with the bootstrap capacitor being charged to a voltage greater than two times the threshold voltage of the field-effect transistors. With a positive voltage applied to the input of the circuit shown in Fig. 1, transistors T1 and T5 turn on and the voltages at the output and at node B are established at or near ground potential. Transistors T2 and T3 are fabricated so that node A is at a voltage greater than two times the threshold voltage of transistor T4, and thus also the feedback capacitor Cfb voltage. With transistor T4 off, the direct-current power is determined by the series resistance of transistors T1, T2 and T3, which is designed to be low.

When the voltage at the input is reduced to approximately zero volts, transistors T1 and T5 turn off and simultaneously the voltages at nodes A and B rise. As the voltage at node B rises, transistor T4 turns on, causing the voltage at the output to rise. This increase in voltage at the output increases the voltage at node A. When the voltage at node A rises to Vdd, transistor T3 turns off and the voltage at the gate of transistor T4 is driven further upward by the output voltage coupled through the feedback transistor Cfb and transistor T2.

The gate-to-source voltage of transi...