Bias Circuit, Sensor Device, and Wireless Sensor Device

A bias circuit comprising:

• a current mirror circuit to include first conductivity type first and second transistors connected between a first power supply node that supplies a first voltage and first and second nodes;
• a current generation circuit to include a second conductivity type transistor connected between a second power supply node that supplies a second voltage and the first and second nodes;
• and
• a starting control circuit to detect, during the starting of the bias circuit, a transition from a first state continuing from before starting to a second state accompanied by the starting, wherein
• control electrodes of the first and second transistors connected to each other are electrically connected to one node that is one of the first and second nodes at least in the second state,
• the bias circuit further comprises a starting circuit to switch a connection destination of the control electrodes between the first state and the second state during the starting of the bias circuit,
• the starting circuit includes
• a first switch connected between a first voltage node that supplies an off-voltage to turn off the first and second transistors and the control electrodes,
• a second switch connected between a third node and the control electrodes, and
• a third switch connected between a second voltage node that supplies an on-voltage to turn on the first and second transistors and the third node,
• the first switch and the second switch are turned off in the first state and turned on in the second state, and
• the third switch is turned on in the first state and turned off in the second state.

A bias circuit comprising:

• a first transistor electrically connected between a first power supply node that supplies a first voltage and a first node;
• a second transistor electrically connected between the first power supply node and a second node, the second transistor having a control electrode connected to a control electrode of the first transistor, the second transistor having the same conductivity type as a conductivity type of the first transistor;
• a current generation circuit connected between a second power supply node that supplies a second voltage and the first and second nodes;
• a first control switch connected between the control electrodes of the first and second transistors and one node that is one of the first and second nodes;
• and
• a second control switch connected between the one node and a node that supplies an on-voltage to turn on the first and second transistors, wherein
• the current generation circuit is configured such that a first element group electrically connected between the first node and the second power supply node is different from a second element group electrically connected between the second node and the second power supply node, and
• the first control switch is turned off when the second control switch is turned on, and the second control switch is turned off when the first control switch is turned on.