Apparatus and method for generating a temperature insensitive reference current
First Claim
1. A constant current source for generating a constant reference current that is relatively temperature insensitive, said constant current source comprising:
- first circuitry for generating a first output current that increases with increases in temperature;
second circuitry for generating a second output current that decreases with increases in temperature; and
a current combiner circuit that receives said first and second output currents at a common connection and combines said first and second output currents to thereby generate said constant reference current, wherein a change in said first output current caused by a temperature change is at least partially offset by a change in said second output current caused by said temperature change.
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Abstract
A constant current source for generating a constant reference current that is relatively temperature insensitive. The constant current source comprises: i) first circuitry for generating a first output current that increases with increases in temperature; ii) second circuitry for generating a second output current that decreases with increases in temperature; and iii) a current combiner circuit that combines the first and second output currents to thereby generate the constant reference current. A change in the first output current caused by a temperature change is at least partially offset by a change in the second output current caused by the temperature change.
14 Citations
20 Claims
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1. A constant current source for generating a constant reference current that is relatively temperature insensitive, said constant current source comprising:
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first circuitry for generating a first output current that increases with increases in temperature; second circuitry for generating a second output current that decreases with increases in temperature; and a current combiner circuit that receives said first and second output currents at a common connection and combines said first and second output currents to thereby generate said constant reference current, wherein a change in said first output current caused by a temperature change is at least partially offset by a change in said second output current caused by said temperature change. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A cellular telephone comprising:
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a voltage regulator capable of receiving a supply voltage from a battery of said cellular telephone and generating a regulated output voltage; analog-to-digital circuitry capable of converting analog signal in said cellular telephone to digital signals; and a constant current source capable of supplying a constant reference current to said voltage regulator and said analog-to-digital circuitry, wherein said constant reference current is relatively temperature insensitive, said constant current source comprising; first circuitry for generating a first output current that increases with increases in temperature; second circuitry for generating a second output current that decreases with increases in temperature; and a current combiner circuit that receives said first and second output currents at a common connection and combines said first and second output currents to thereby generate said constant reference current, wherein a change in said first output current caused by a temperature change is at least partially offset by a change in said second output current caused by said temperature change. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method of generating a constant reference current that is relatively temperature insensitive, the method comprising the steps of:
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generating a first output current that increases with increases in temperature; generating a second output current that decreases with increases in temperature; and combining the first and second output currents at a common connection to thereby generate the constant reference current, wherein a change in the first output current caused by a temperature change is at least partially offset by a change in the second output current caused by the temperature change. - View Dependent Claims (18, 19, 20)
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Specification