Precharge circuits and methods for dc-dc boost converters

A precharge circuit configured with a DC-DC boost converter, the precharge circuit comprising:

• a) a current mirror circuit having a reference transistor and a power transistor;
• b) a voltage clamping circuit coupled to said current mirror circuit, wherein said voltage clamping circuit is configured to maintain drain-source voltages of said reference transistor and said power transistor as substantially equal;
• and
• c) a current regulating circuit coupled to said current mirror circuit and said voltage clamping circuit, wherein said current regulating circuit is configured to compare a voltage from said voltage clamping circuit against a reference voltage, and to control in response thereto regulation of a reference current and a precharging current of said precharge circuit as substantially constant.