A voltage to frequency conversion system may be used in association with clock related applications such as a closed loop oscillator. The voltage to frequency conversion system includes independent current sources that are synchronously operated to generate substantially the same respective output currents under varying temperature and supply voltage conditions. One of the current sources is used to generate a reference voltage, and the other of the current sources is used to charge a capacitor in a predetermined ramp. The capacitor may be selectively charged and discharged based on a frequency of an input signal, and an average of the variable charge voltage of the capacitor may be compared to the reference voltage to generate an analog output signal indicative of frequency.