Cmos Charge Pump1
Cmos Charge Pump1
Cmos Charge Pump1
By:- GAURAV
KUMAR 3136602
Objectives
Introduction Charge Pump Dickson Charge Pump NCP-2 Charge Pump Proposed Charge Pump Simulation Results Applications Conclusion References
INTRODUCTION
Power consumption is crucial consideration in design of VLSI Most common method to reduce the power consumption is to reduce the power supply voltage. Basic circuit used is charge pump.
CHARGE PUMP
Charge Pump circuits are switching mode power converters. Charge pumps are also called level shifter.
Basic Charge pump transfers charge packets from power supply to output, using only capacitor and switches.
Cont..
Basic circuit of charge pump
Cont..
The Voltage fluctuation is given by V= Vclk.
o o o o o o Vclk is voltage amplitude of clock signal C is pumping capacitor Cs is parasitic capacitance Io is output current and f is frequency of clock
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(+)
()
Cont.
The difference between the source and the bulk terminals voltages increases in the later stages of the circuit. The threshold voltage Vth of the diode-connected NMOS becomes larger due to body effect. So the pumping efficiency reduced by the Body effect.
Cont.
Static Charge Pump
Cont.
Dynamic charge pump.
Cont.
The output of the NCP-2 charge pump is diode connected NMOS transistor and this leads to reduction of output voltage. due to body effect.
Cont..
The Proposed charge pump and associated waveforms at the pumping nodes
Cont..
Output of proposed charge pump is 5xVDD in ideal conditions. At any of the stage, the voltages Vgd, Vgs have a maximum of VDD, the supply voltage. As a result, the gate oxide reliability is increased and stressing of gate oxide due to high DC voltage is avoided.
SIMULATION RESULT
Simulated output voltages of Dickson, NCP-2 and Proposed charge pump for Different input voltages is shown in fig.6
Fig.6
Future Applications
Charge Pump Regulator for Micro-colour TFT Panel. Phase Lock Loop. Memories such as EEPROM, Flash Memories. As LCD or white LED drivers
CONCLUSION
A charge pump in standard CMOS process suited for low voltage is presented. The influence of the threshold voltage of the switch transistor is almost eliminated and the pumping efficiency of the circuit is improved.
REFERENCES
[1] Chun Yu Cheng, Ka Nang Leung, Yi Ki Sun and Pui Ying Or Design of a LowVoltage CMOS Charge Pump,IEEE J.2008 (http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4459568&tag=1) [2] Mohammad Mahdi Ahmadi and Graham Jullien A CMOS charge pump for low voltage operation, IEEE J. 2000 (ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=857500) [3] Shantanu A. Bhalerao, Abhishek V. Chaudhary, Rajendra M. Patrikar CMOS Low Voltage Charge Pump,IEEE J. 2007 [4] Y. Moisiadis, I. Bouras, A. Arapoyanni A CMOS charge pump for low voltage application.,IEEE J. ISCAS 2000 may 28-31 http://en.wikipedia.org/wiki/Charge_pump
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