New error amplifier topology for Low Dropout Voltage regulators using compound OTA-OPAMP
Typical Low Dropout Voltage regulators (LDO), uses an error amplifier in a linear closed loop. The main advantage of such linear regulators is the low standby current due to the absence of switching. In addition, a fully integrated linear regulator with no external components is very attractive for applications with stringent area, low weight requirements and relatively small peak power. The architecture of error amplifier used in the feedback loop suffers from an inherent load regulation performance limitation. This limitation manifests itself through the limited DC open-loop gain, and results from limited closed-loop bandwidth. The frequency response of power supply loop is highly sensitive to the load conditions, thus, making proper compensation is a laborious effort. This paper discusses and addresses a new topology of an error amplifier offering a high open loop gain as well as a large band width by adding a zero to its transfer function. Proposed topology uses a compound OTA and OPAMP that enhances load regulation performance by relaxing the dc open-loop gain restrictions. An example of battery charger using this OpAmp topology is also described in this paper. This battery charger can be used as an LDO once the battery is not connected.
WOS:000245212800129
2007
536
539
Enz, C Declercq, M Leblebici, Y
32nd European Solid-State Circuits Conference
Sep 19-21, 2006
Montreux, SWITZERLAND
Export Date: 19 January 2010
Source: Scopus
Art. No.: 4099822
References: Tantawy, R., Brauer, E.J., Performance Evaluation of CMOS Low Drop-Out Voltage Regulators (2004) The 47th IEEE International Midwest Symposium on Circuits and Systems; Endoh, T., et., al., An On-Chip 96.5% Current Efficiency CMOS Linear Regulator Using a Flexible Control Technique of Output Current (2001) IEEE Journal of Solid-State Circuits, 36 (1). , January; Larson, et., al., 'Low Dropout Voltage Regulator Circuit Including Gate Offset Servo Circuit Powered by Charge Pump' Patent No, US 6,188,212 B1. Feb. 13 2001Rincon-Mora, 'Current-Efficient Low-Drop-Out Voltage Regulator and Frequency Response' Patent No, US 6,188,211 B1. Feb. 13 2001Rincon-Mora, G., et., al., A low-Voltage, Low Quiescent Current Low Drop-Out Regulator (1998) IEEE Journal of Solid-State Circuits, 33 (1). , January; Rincon-Mora, G., et., al., Optimized FrequencyShaping Circuit Topologies for LDO's (1998) IEEE Transactions on circuits and systems, 45 (6). , June; Chester Simpson, National Semiconductor report- santa Clara, 'A User's Guide to compensating Low-Dropout Regulators'Alex Ka Nang Leung et. al. 'Damping-Factor-Control Frequency Compensation technique for Low-Voltage Low-Power Large Capacitive Load Applications', ISSCC99/Session 8/ Paper TA 8.7 PP 158Hazucha, P., An Area-Efficient, Integrated (2004) Linear Regulator with Ultra-Fast Load Regulation, Symposium, , On VLSI Circuits Digest of Technical Papers, IEEE; Fan, X., Sigle Miller Capacitor Frequency Compensation Technique for Low-Power Multistage Amplifiers (2005) IEEE Journal of Solide-State Circuits, 40 (3). , March; Chava, C.K., Silva-Martínez, J., A Frequency Compensation Scheme for LDO Voltage Regulators (2004) IEEE Transactions on Circuits and Systems, 51 (6). , JUNE; M. Kayal, ph. Deval, F. Vaucher, US_Patent, 20040246052, Load and line regulation using operational transconductance amplifier and operational amplifier in tandemwww.microchip.com, MCP7386X Data SheetUR - http://www.scopus.com/inward/record.url?eid=2-s2.0-39749133621&partnerID=40
REVIEWED
EPFL