Voltage source device for low-voltage operation
AssigneeMotorola, Inc.
InventorTakatsugu Kamata
Life of this patent
Estimating the term…
Abstract
A voltage source device for low-voltage operation which sources a desired voltage while minimizing variations in output voltage due to changes in temperature. The voltage source device includes a current source circuit having a temperature characteristic of (1/T)-a and a compensation circuit having a temperature characteristic that includes a term of -1/T, which compensates for the temperature characteristic of the current source circuit. The voltage source device also includes a voltage conversion circuit for converting the power supply current provided by the current source circuit into a power supply voltage and outputting it externally.
Claims3
A voltage source device for low-voltage operation, comprising:
- a current source circuit using a bandgap voltage, said current source circuit having a temperature characteristic of (1/T)-2 (where T is an ambient temperature and a is a constant);
- a compensation circuit, having a temperature characteristic including at least a term of -1/T, said compensation circuit compensating for the temperature characteristic of said current source circuit;
- and
- a voltage conversion circuit for converting the power supply current provided by said current source circuit into a power supply voltage.
A voltage source device for low-voltage operation, comprising:
- a current source circuit using a bandgap voltage, said current source circuit having a temperature characteristic of (1/T)-2 (where T is an ambient temperature and a is a constant);
- a compensation circuit for compensating for the temperature characteristic of said current source circuit;
- and
- a voltage conversion circuit for converting the power supply current provided by said current source circuit into a power supply voltage;
- wherein said compensation circuit including:
- a pair of first and second transistors, having collector terminals connected to a high-potential power supply line, emitter terminals connected to a low-potential power supply line, and base terminals connected in common;
- a third transistor having a base terminal connected to the collector terminal of said first transistor, a collector terminal connected to the collector terminal of said second transistor, and an emitter terminal connected to the base terminals of said first and second transistors connected in common;
- and
- a resistor having one end connected to the base terminals of said first and second transistors connected in common, and the other terminal connected to the low-potential power supply line.
A voltage source device for low-voltage operation, comprising:
- a current source circuit using a bandgap voltage, said current source circuit having a temperature characteristic of (b 1/T)-2 (where T is an ambient temperature and a is a constant);
- first and second compensation circuits for compensating for the temperature characteristic of said current source circuit;
- and
- a voltage conversion circuit for converting the power supply current provided by said current source circuit into a power supply voltage;
- wherein said first compensation circuit including:
- a pair of first and second transistors having collector terminals connected to a high-potential power supply line, emitter terminals connected to a low-potential power supply line, and base terminals connected in common;
- a third transistor having a base terminal connected to the collector terminal of said first transistor, a collector terminal connected to the collector terminal of said second transistor, and an emitter terminal connected to the base terminals of said first and second transistors connected in common;
- and
- a resistor having one end connected to the base terminals of said first and second transistors connected in common, and the other end connected to the low-potential power supply line;
- and
- wherein said second compensation circuit including:
- a resistor having one end connected to the base terminals of said first and second transistors connected in common;
- a fourth transistor having its base and collector terminals connected to the other end of said resistor, and an emitter terminal connected to the low-potential power supply line;
- and
- a current supply circuit for supplying a predetermined constant current to the base and collector terminals of said fourth transistor.
Dependencies are inferred from the claim text.