SWITCHED CAPACITOR BIAS CIRCUIT GENERATING REFERENCE SIGNAL PROPORTIONAL TO ABSOLUTE TEMPERATURE, CAPACITY AND CLOCK FREQUENCY

摘要

PROBLEM TO BE SOLVED: To compensate fluctuation in load capacity and a temperature and to minimize power dissipation by generating bias current proportional to capacity, a clock frequency and an absolute temperature through the use of an integrated capacitor and a duplex sample-type switched capacitor 'resistance' in a PTAT loop proportional to an absolute temperature. SOLUTION: A switched capacitor bias circuit generating a reference signal proportional to an absolute temperature, capacity and a clock signal frequency uses an integrated capacitor CI and a duplex sample-type switched capacitor 'resistor' Sc in a PTAT loop for generating output bias current Ibias proportional to a clock, an absolute temperature and load capacity. Transistors M1, M2, M4 and M5 form a part of a current mirror circuit biased by a bias circuit formed of transistors M3 and M6. Capacitor CI, the switched capacitor Cs and transistors Msa-Msd form a switched capacitor circuit.