Patent ID: 7477532

Claim:
A voltage start-up circuit comprising: a high voltage element having an input for receiving an input voltage, a first output configured to form an intermediate voltage from the input voltage, and a second output configured to form a first current; a first transistor coupled to receive a substantially constant current derived from the intermediate voltage, the first transistor having a first current carrying electrode coupled to receive the substantially constant current, a control electrode, and a second current carrying electrode; a first resistor configured to receive the first current; a first diode coupled bipolar transistor that is coupled between the first transistor and the first resistor, the first diode coupled bipolar transistor having a collector and a base coupled to the control electrode of the first transistor, and an emitter; and a second diode coupled bipolar transistor that is coupled between the first resistor and the first transistor, the second diode coupled bipolar transistor having a collector and an base coupled to the emitter of the first bipolar transistor and an emitter coupled to a first terminal of the first resistor.