The present invention can be employed with any power supply circuit where it is desirable to employ a ratio adaptive, gated oscillator based step up switching regulator with a selectable duty cycle. By selecting a particular value for a capacitor coupled between the regulator's Frequency and Switch pins, a user can optimize the regulator's duty cycle for a particular application. Also, by adding a resistor in series with the capacitor, a time constant is created that limits the total charge transfer from taking place at high frequencies more than it does at low frequencies. Additionally, by selecting particular values for the capacitor and resistor, the user can adjust the duty cycle for an application as a function of the battery voltage and output voltage.
The switching DC-DC converter comprises an inductor, a control circuit with an oscillator and an output stage, the output stage being coupled to the inductor, a diode coupled to the inductor, and a feedback loop for generating a stabilized output voltage. An output voltage of the output stage is coupled with an oscillator input of the control circuit, for example via an impedance, for synchronizing an oscillation cycle of the oscillator with a current pulse of the output stage.
