How can the switching frequency of a switching regulator be controlled?
While many switching regulators have a non-adjustable, fixed switching frequency, some have provisions for changing or controlling this frequency. There are three techniques used to change the switching frequency of a switching regulator IC. (1) One approach uses an external resistor to change a capacitor charge current within the oscillator. (2) Some regulators can be synchronized with an external oscillator. (3) A few regulators have multiple pre-set switching frequencies that can be selected by connecting a pin to either ground or the Vcc supply line.
