| 摘要 |
<p>PROBLEM TO BE SOLVED: To operate a voltage controlled oscillator circuit at high speed by using a chopper comparator operated at high speed. SOLUTION: The voltage controlled oscillator circuit is provided with two chopper type comparators 20, 21, a capacitor 22 that supplies a comparison voltage Vc to the two chopper comparators 20, 21, two current sources 23, 24 to charge or discharge the capacitor 22, a conversion circuit 25 that allows two current sources 23, 24 to produce a current in proportion to an input voltage Vin, two switching elements 26, 27 and an inverter 28 to control ON/OFF of the two current sources 23, 24, and a logic circuit 29 that latches an output signal of the two comparators 20, 21, outputs an output voltage Vout being an oscillation signal of the voltage controlled oscillator circuit and generates a clock signalϕ1 and an inverse of the clock signalϕ1 to switch the operation of the two chopper type comparators 20, 21.</p> |
