Reference current source circuit

A reference current source circuit comprising:

• a constant current circuit configured to generate a reference current;
• and
• a starting circuit configured to sink a starting current from the constant current circuit at startup, wherein the starting circuit includes
• a first transistor,
• an impedance circuit provided between the first transistor and a ground line,
• a first current mirror circuit provided between the first transistor and a power supply line to return a current that flows to the first transistor,
• a second current mirror circuit configured to return an output current from the first current mirror circuit, and generate the starting current,
• an inverter having an input connected to a connection node between the first transistor and the first current mirror circuit, and having an output connected to a control terminal of the first transistor,
• a first current source configured to generate a first current when a power supply voltage of the power supply line has exceeded a first threshold value,
• a third current mirror circuit configured to draw a current proportional to the first current from an input side of the second current mirror circuit, and
• a second current source configured to supply a second current to the connection node between the first transistor and the first current mirror circuit when the power supply voltage has exceeded a second threshold value higher than the first threshold value.