An oscillator for a DC-DC converter, which is able to obtain constant frequency
by using trans-conductance value as a clock of the DC-DC converter to make an output
insensitive for process changes, comprises: a trans-conductance unit calculating
trans-conductance value according to input voltage, deciding and outputting current
according to the input voltage; a capacitor charged by the current outputted from
the trans-conductance unit; and an amp-type Schmitt trigger comparing the voltage
charged in the capacitor to threshold voltage, and outputting the compared value.
