A regulating circuit for automobile light for outputting an elevated voltage to power an operation of a driving integrated circuit, comprises a first diode having its anode interconnected to an input of the power supply (forward biased) and interconnected to the first diode in serial (reverse biased) and then interconnected to a driving integrated circuit. The first diode is used to detect a maximum voltage input, and the second diode is used to restore its energy to the capacitor so as to keep the voltage output maintained in an elevated level. As a result, the regulating circuit can be used with all kinds of driving integrated circuit incorporated in the automobile headlight.