| 摘要 |
A method and circuit for producing an output current is provided. The method and circuit adds two currents with opposing temperature coefficients to produce such output current. A first one of the two currents, I1, is a scaled copy of current produced in a temperature compensated bandgap reference circuit. A second one of the two currents, I2, is derived from a temperature stable voltage produced by the bandgap circuit divided by a positive temperature coefficient resistance. The added currents, I1+I2, provide the output current. The circuit includes a first circuit for producing: (i) a reference current having a positive temperature coefficient; and (ii) an output voltage at an output node substantially insensitive to variations in supply voltage and temperature over a predetermined range. The current source includes a second circuit connected to the output node for producing a first current derived from the bandgap reference current. The first current has a positive temperature coefficient. Also provided is a third circuit connected to the output node for producing a second current derived from the output voltage, such second current having a negative temperature coefficient. The first and second currents are summed at the output node to produce, at the output node, an output current related to the sum of the first and second currents, such output current being substantially insensitive to variations in temperature and supply voltage over the predetermined range.
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