Compensation for light-induced current in an integrated circuit

A circuit to compensate for light induced current in an unpackaged integrated circuit, the circuit comprising:

• a first circuit having a first light sensitive N-well resistor, and an output terminal for providing a first current, wherein at least a portion of the first current is a function of the first light sensitive N-well resistor;
• a compensation circuit having a current mirror and a second light sensitive N-well resistor, the current mirror having an input terminal coupled to receive a second current that is mirrored from the first current, and an output terminal coupled to provide a third current in response to the second current, the second light sensitive N-well resistor configured to match the first light sensitive N-well resistor and to compensate for a light induced current component provided by the first light sensitive N-well resistor, wherein the third current is provided without a light generated current component;
• and
• the current mirror of the compensation circuit further comprising:
• a first transistor having a first current electrode and a control electrode coupled to receive the first current, and a second current electrode coupled to ground;
• and
• a second transistor having a first current electrode, a control electrode coupled to the control electrode of the first transistor, and a second current electrode coupled to ground.

A bias circuit to compensate for light induced current in an unpackaged integrated circuit, the bias circuit comprising:

• a first circuit comprising:
• a first transistor having a first current electrode coupled to a power supply voltage, and a second current electrode and a control electrode coupled together;
• a second transistor having a first current electrode coupled to a power supply voltage, a second current electrode, and a control electrode coupled to both the control electrode and the second current electrode of the first transistor, and a second current electrode;
• and
• a third transistor having a first current electrode coupled to the second current electrode of the first transistor, a control electrode, and a second current electrode;
• a fourth transistor having a first current electrode and a control electrode coupled to both the second current electrode of the second transistor and to the control electrode of the third transistor, and a second current electrode coupled to a ground terminal;
• a light sensitive component having a first terminal coupled to the second current electrode of the third transistor, and a second terminal coupled to ground;
• a compensation circuit comprising:
• a fifth transistor having a first current electrode coupled to the power supply voltage, a control electrode coupled to the current electrode of the first transistor, and a second current electrode;
• a sixth transistor having a first current electrode coupled to the power supply voltage, and a second current electrode and a control electrode coupled together;
• a seventh transistor having a first current electrode and a control electrode coupled to the second current electrode of the fifth transistor, and a second current electrode coupled to the ground;
• and
• an eighth transistor having a first current electrode coupled to the second current electrode of the sixth transistor, a control electrode coupled to the second current electrode of the fifth transistor, and a second current electrode coupled to the ground terminal;
• and
• a second light sensitive component having first and second terminals both coupled to the second current electrode of the fifth transistor.