| 摘要 |
PURPOSE:To vary the substrate bias according to the output voltage of the inverter by controlling the level of clamp potential through selective connection to the feedback path with application of a bootstrap type feedback to FET under the load of an E (enhancement) type MOS inverter. CONSTITUTION:The output of a generator 1 drives an E-type inverter 2 employing a MOSFET Q7/Q8. When the output is VH, a MOSFET Q11 is turned on, and D (depletion) type MOSFET Q10 is charged so that the potential of the contact e reaches -VH at OV. Therefore, if the threshold of the E-type MOSFET is VTH, the output VTH-VH develops at the terminal f. When the gate input of the D-type MOSFET Q9 is OV while the output terminal c is at OV, the potential of a contact d on the D-type MOSFET Q13 (capacity) reaches 2VDD-VTH. Thus, the potential VTH-VDD develops at the terminal f. When a high level input is applied to the gate a, the FET Q9 is turned on and the contact d is clamped at a potential VDD. Only the output VDD-VTH develops at the output terminal, leading the output of the terminal f to be 2VTH-VDD. In this manner, the power consumption and the working speed can be switched by changing the bias of the substrate. |
