Abstract:
High-color-depth LCD drivers require nF-range capacitors as the charge reservoirs to handle the glitch energy during the conversion of the DAC [1]. The reference buffers ...Show MoreMetadata
Abstract:
High-color-depth LCD drivers require nF-range capacitors as the charge reservoirs to handle the glitch energy during the conversion of the DAC [1]. The reference buffers based on multi-stage amplifiers can enhance the precision under low-voltage supplies, but are exposed to instability when loaded by such large capacitive loads (CL). Frequency compensation via damping-factor control [2] is capable of extending the CL-drivability up to 1nF, however, at the cost of penalizing the power (426μW) and area (0.14mm2). Although recent works [3-4] have enhanced gain-bandwidth product (GBW) and slew rate (SR) showing better FOMS (=GBW·CL/Power) and FOML (=SR·CL/Power), the CL-drivability has not been improved (i.e., 0.8nF in [3] and 0.15nF in [4]). This paper describes a three-stage amplifier managed to afford particularly large and wide range of CL (1 to 15nF) with optimized power (144μW) and die size (0.016mm2), being very suitable for compact LCD drivers [5] with different resolution targets. The design barriers are methodically surmounted via local feedback loop (LFL) analysis expanded from [6], which is an insightful control-centric method. Measured at 15nF CL, the attained FOMS (FOML) is >;4.48× (>;2.55×) beyond that of the state-of-the-art (Fig. 21.6.1).
Published in: 2012 IEEE International Solid-State Circuits Conference
Date of Conference: 19-23 February 2012
Date Added to IEEE Xplore: 03 April 2012
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