Synchronous Dynamic Circuit Techniques

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Synchronous Dynamic Circuit Techniques:

Dynamic Pass Transistor Circuits:- The circuit consists of cascaded combinational logic which are interconnected through nMOS pass transistors. The operation of the circuit depends on charge storage in theinput capasitor.  and signal timing scheme is also called two-phase clocking.

Two-Phase Clock Dynamic Shift Resistor:-

A dynamic shift register circuit comprises an input terminal and an output terminal. It further comprises a first transfer gate circuit connected to the input terminal for receiving an input signal and transferring the input signal under the control of a first clock signal; an inverter circuit for inverting a level of an output signal of the first transfer gate circuit; a second transfer gate circuit connected to the inverter circuit for receiving an output signal of the inverter circuit and transferring the same under the control of a second clock signal which has a level opposite to that of the first clock signal; a signal follower circuit for producing an output signal having a level which follows a level of the output signal of the first transfer gate circuit; and a logic circuit connected to first and second power source voltages. 

Depletion-Load Dynamic Shift Register: The max clock frequency is determined by signal propagation delay through one inverter stage.One half-period of the clock signal must be long enough to allow Cin to charge up or down, and Cout to charge to the new value.The logic-high input value is one VT0 lower than VDD.

Enhancement-Load Dynamic Shift Register:  Instead of biasing load transistors with a constant gate voltage, a clock signal is applied to the gate of the load transistor Þ power dissipation and silicon area are reduced.The power supply current flows only when the load devices are activated by the clock signal, the power consumption is lower than the depletion-load nMOS logic.

References

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Author-Sahil Gupta 

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