FinalProject_PartIII_ProjectReport

8/13/2019 FinalProject_PartIII_ProjectReport

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EEE 433/591 Fin al Pro ject

Par t III

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Name:Srikanth Reddy ParamaiahgariASU ID:1206321047


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General Rules

If you directly import cadence plots into your

presentation, they must have clearly visible axes, whitebackground or CLEARLY labeled on black background,and solid easily viewable traces.

All schematics must be clearly annotated!

All hand analysis may be scanned and pasted into thecorresponding slide(s).Please ensure that your hand analysis follows the samenaming scheme as your circuits/simulations.

Please clearly mark all simulation axes (or title thesimulation plots) (I do not know what V/net5 is!).

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Summary of LDO Specifications

Given specifications Hand analysiscalculated

Obtained from simulation

Voltage supply 2.5 V 2.5 VLoad current to be delivered Upto 50 mA 50 mA

Ripple % 5% 0.8%

Output regulated Voltage 2.25V 2.25V

Loop gain (Low frequency) forIL=50mA

62 dB 69.37 dB

Closed loop gain (Lowfrequency) for IL=50mA

6.056 dB

3 dB bandwidth (closed loop) 1.128 MHz

3 dB Bandwidth(open loop) 2.5 KHz 1.676 KHz

PSRR 50 dB

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Block Diagram of LDO

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Circuit Diagram of Differential Amplifier

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DC Biasing Circuit Snapshot(s)

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AC Hand Analysis (1/2)

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AC Hand Analysis (2/2)

Extra space for AC analysis.

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Loop Gain AC Simulation

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Loop Gain Compensation Discussion

COMPENSATION:

The compension used is in stabilizing the system is thelead compensation. I tried to introduce a zero just afterthe unity gain frequency so that the phase is raised bythe considerable amount at the unity gain frequencythereby increasing the phase margin.

In my design CL=1 uF, ESR= 1 ohm , Rc=2.8 K Cc=158pF.I have first assumed Cc as 5 pF and plotted the acresponse. I found that for phase of -120 degrees(60degree phase margin) the gain was 31.6 V/V . So inorder to reduce the gain for that phase to zero Imultiplied Cc with the gain at that point= 5*31.6= 158 pF.

And Rc is calculated by Rc= 1/(1.7*2*pi*fT*Cc)= 2.8 KOhms.

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Loop Gain AC Simulation w/Compensation(IL=1mA)

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PSRR Simulations

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Transient Simulation (1/2)

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THE ENDNo vague discussions required.

FinalProject_PartIII_ProjectReport

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