Oscillator system and method thereof. The oscillator system includes a first voltage-to-current converter configured to receive a first voltage and generate a first current based on at least information associated with the first voltage, and a second voltage-to-current converter configured to receive a second voltage and generate a second current based on at least information associated with the second voltage. Additionally, the oscillator system further includes a current-mode N-bit digital-to-analog converter configured to receive at least the second current and a first clock signal and to generate a third current based on at least information associated with the second current and the first clock signal. N is a first integer. The first clock signal is associated with a first clock frequency corresponding to a first clock period. Moreover, the oscillator system further includes a current comparator coupled to the first voltage-to-current converter and the current-mode N-bit digital-to-analog converter.