The invention discloses a relaxation-type
voltage-controlled oscillator, which is composed of a charging
capacitor, a switching tube
assembly, a comparison circuit, a charging
current source and a
logic control circuit, and is characterized by being provided with the charging
current source which is formed by a
constant current source and a controlled
current source in parallel; the switching tube
assembly is formed by a first group and a second group of four switches; the charging
capacitor is connected with a first group of switching tubes and a second group of switching tubes; the comparison circuit is formed by a cross-coupled geminate
transistor, and is connected with the two positive and negative ends of the charging
capacitor; the cross-coupled geminate
transistor comprises a first
clamper tube and a second
clamper tube, wherein, the input end of the first
clamper tube is connected with the output end of the second clamper tube; and the input end of the second clamper tube is connected with the output end of the first clamper tube. The relaxation-type
voltage-controlled oscillator of the invention adopts the break-over
voltage of a
semiconductor tube as a comparison voltage, improves the oscillating frequency through improving the structure of the controlled circuit source, has high
linearity, adopts a current source to avoid the
consistency problem of the process, and is easier to realize.