| 摘要 |
A voltage controlled oscillator is provided to change a frequency to a desired value without an additional feedback system by changing the frequency linearly through the voltage DA conversion. A voltage controlled oscillator includes a capacitor, a current source, a current sink, a switching unit, a voltage DA converter, a comparator, and a latch unit. The current source is connected to the power. The current sink is connected to the ground. The switching unit is connected between the current source and the current sink and switches the charging path and the discharge path. An amplification degree is variably determined according to the converting signal. The voltage DA converter(300) amplifies the difference voltage between a preset lower limit reference voltage and a common voltage and supplies the added voltage to an upper limit reference voltage by adding the amplified voltage to the common voltage. The comparator generates a set signal and a reset signal by comparing the charging voltage of a capacitor, the upper limit reference voltage, and the lower limit reference voltage. The latch unit(500) performs an RS latching operation according the set signal and the reset signal from the comparator and controls the charging and discharging of the switch unit by using an output signal according to the RS latch operation. |
