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This paper proposes a compact, low-power, and rail-to-rail class-B output buffer for driving the large column line capacitance of LCDs. The comparator used as a nonlinear element in feedback path is modified from the current-mirror amplifier, which has area and power advantages. The output buffer was realized in a 0.35 m CMOS process. The active area of the buffer is 8673.5 m2. With a 3.3 V supply, the measured quiescent current is 7.4 A. The settling time for 0.05-3.25 V swing to within 0.2% is 8 s.
This paper describes the design and results of low cost integrated CMOS local and remote temperature sensors with digital outputs. No trimming is needed to obtain good temperature linearity, so that only one-temperature calibration is needed which greatly reduces testing cost. The base-emitter voltage of the parasitic substrate bipolar transistor is used to measure the local temperature. A diode-connected external bipolar transistor is used to measure the remote temperature. Chopper techniques were used to cancel the offset voltage of the op-amp, so that a precise bandgap voltage can be obtained without resistance trimming. A first order ΣΔ ADC was used to produce the digital output. The local and remote temperature sensors were realized in a 0.6 µm single-poly triple-metal CMOS technology with active area of 0.6 mm2 and 0.65 mm2, respectively. After calibration, the error is 1 for the local temperature sensor over the temperature range of -20 to 130, and 2 for the remote temperature sensor over the range of 0 to 120. The supply currents of the local and remote temperature sensors are 3.5 µA and 38 µA at 8 samples/s, respectively.