CPC H02M 1/36 (2013.01) [H02M 3/33507 (2013.01)] | 15 Claims |
10. An interface circuit to couple an input voltage in a first voltage domain to a controller of a power converter circuit in a second voltage domain, the interface circuit comprising:
a depletion-mode transistor having a gate terminal, a source terminal, a drain terminal, and a substrate terminal, wherein the substrate terminal is connected to a ground potential;
a start-up circuit including:
a current limiter circuit having an input coupled to with a terminal of a high-voltage transistor, the current limiter circuit having an output coupled to with and provide an input voltage to an input of the controller of the power converter circuit; and
a first shunt regulator circuit having an input coupled to with the terminal of the high-voltage transistor, the first shunt regulator circuit to maintain a first voltage at the terminal of the high-voltage transistor; and
a line voltage detection circuit to sense a current proportional to a line voltage, the line voltage detection circuit including:
a second shunt regulator circuit having an input coupled to with the terminal of the high-voltage transistor, the second shunt regulator circuit to maintain a second voltage at the terminal of the high-voltage transistor, the second voltage lower than the first voltage.
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