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Power Efficient, Low Area Charge Pump

IP.com Disclosure Number: IPCOM000245801D
Publication Date: 2016-Apr-08
Document File: 4 page(s) / 285K

Publishing Venue

The IP.com Prior Art Database

Related People

Tae-Song Chung: INVENTOR [+3]

Abstract

Pelliconi style charge pump (CP) architecture is generally used in generating 2*VDD and –VDD voltages. But the frequently used simple Pelliconi CP architecture with cross coupled PMOS and NMOS switches is inherently inefficient as the two series switches in CP might be ON at the same time causing short circuit current. To avoid this, gates of PMOS and NMOS switches need to be controlled independently with a non-overlapping clock to avoid short circuit path. The additional circuitry that is added should not consume too much power as it increases the overall power consumption and degrades the efficiency. To solve this problem, a low power and low area circuitry comprising of dynamic level shifters and a novel way of providing power/supply to them has been introduced which would overall result in a lower power, more efficient charge pump. Or for the same power, CP output voltage can be increased, increasing the SNR of the system. Also, the saving of silicon area is huge as the main CP flyback capacitor is reused as the supply to the level shifters.

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Page 01 of 4

Power Efficient, Low Area Charge Pump

Power Efficient, Low Area Charge Pump


1. Inventor(s): Tae-Song Chung, Ranga Seshu Paladugu, Chunbo Liu


2. Synaptics Incorporated, San Jose CA, USA


3. Short Summary

Pelliconi style charge pump (CP) architecture is generally used in generating 2*VDD and -VDD voltages. But the frequently used simple Pelliconi CP architecture with cross coupled PMOS and NMOS switches is inherently inefficient as the two series switches in CP might be ON at the same time causing short circuit current. To avoid this, gates of PMOS and NMOS switches need to be controlled independently with a non-overlapping clock to avoid short circuit path. The additional circuitry that is added should not consume too much power as it increases the overall power consumption and degrades the efficiency. To solve this problem, a low power and low area circuitry comprising of dynamic level shifters and a novel way of providing power/supply to them has been introduced which would overall result in a lower power, more efficient charge pump. Or for the same power, CP output voltage can be increased, increasing the SNR of the system. Also, the saving of silicon area is huge as the main CP flyback capacitor is reused as the supply to the level shifters.

Figure 1 - Pelliconi Style CP

Copyright © 2016 Synaptics Incorporated, All Rights Reserved.

                                                                 Page: 1 of 4 Information contained in this publication is provided as-is, with no express or implied warranties, including any warranty of merchantability, fitness for any particular purpose, or non-infringement. Synaptics Incorporated assumes no liability whatsoever for any use of the information contained herein, including any liability for intellectual property infringement. This publication conveys no express or implied licenses to any intellectual property rights belonging to Synaptics or any other party. Synaptics may, from time to time and at its sole option, update the information contained herein without notice.

Ranga Seshu Paladugu


Page 02 of 4

Power Efficient, Low Area Charge Pump


4. Some Problems Solved

Examples of some of the problems addressed by the invention include:

One of the solution is to control the gates using high voltage level shifters, with power supply coming from separate auxiliary charge pump (CP) which results in significantly higher area because of large reservoir caps, flyback caps, etc., higher power consumption and lower efficiency CP compared to this solution. Some of the solutions used static level shifters to control the gates of switches which also result in higher overall power consumption. Some solutions controlled only PMOS switches gates using HV level shifters with supply from the output of main CP, but that might result in startup problems if not careful and also does not improve the CP efficiency as much as the current solution does.

5. General Description

 A charge pump (CP) is used to in sensor applications to improve the SNR of the system.

Pelliconi...