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Current reference circuit for temperature and process compensation

A technology for generating reference current and reference voltage, which is applied in the direction of adjusting electrical variables, control/regulation systems, instruments, etc., and can solve problems such as errors

Active Publication Date: 2015-07-08
STMICROELECTRONICS (SHENZHEN) R&D CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the resistance of resistor R1 is process corner dependent, and the resistance value may vary by more than ±30% from process to process
This can cause significant errors in reference current generation

Method used

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  • Current reference circuit for temperature and process compensation
  • Current reference circuit for temperature and process compensation
  • Current reference circuit for temperature and process compensation

Examples

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Embodiment Construction

[0017] now refer to figure 2 , which illustrates a circuit diagram of an embodiment of a temperature and process compensated reference current generator circuit 110 . Circuit 110 includes an operational amplifier 112 having a non-inverting (positive) input 114 and an inverting (negative) input 116 . The non-inverting input terminal 114 is configured to receive a first reference voltage V1=aV T . In this case, V T =kT / q is known to those skilled in the art and a is a scaling constant set by the circuit designer for the reference voltage generator. Amplifier 112 is powered from positive and negative voltage supply nodes, in this case as indicated by voltage Vana3V3 (eg, an analog circuit supply voltage of 3V) and ground. The amplifier includes an output node 118 coupled to the gate of transistor 120 . Transistor 120 is an n-channel MOSFET device. The source-drain path of transistor 120 is coupled between a positive voltage supply node and a negative voltage supply node. ...

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PUM

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Abstract

A reference current path carries a reference current. A first transistor is coupled to the reference current path. A second transistor is also coupled to the reference current path. The first and second transistors are connected in parallel to carry the reference current. The first transistor is biased by a first voltage (which is a bandgap voltage plus a threshold voltage). The second transistor is biased by a second voltage (which is a PTAT voltage plus a threshold voltage). The first and second transistors are thus biased by voltages having different and opposite temperature coefficients with a result that the temperature coefficients of the currents flowing in the first and second transistors are opposite and the reference current accordingly has a low temperature coefficient.

Description

technical field [0001] The present invention relates generally to electronic circuits, and more particularly to circuits for generating reference currents. Background technique [0002] refer to figure 1 , which illustrates a conventional current reference generator circuit 10 . Circuit 10 includes an operational amplifier 12 having a non-inverting (positive) input 14 and an inverting (negative) input 16 . The non-inverting input 14 is configured to receive a reference voltage. In one exemplary embodiment, the reference voltage is a bandgap reference voltage (VBG) generated by a bandgap voltage generator circuit (known to those skilled in the art). Amplifier 12 is powered from positive and negative voltage supply nodes, in this case indicated by voltage Vana3V3 (eg an analog circuit supply voltage of 3V) and ground. The amplifier includes an output node 18 coupled to the gate of transistor 20 . Transistor 20 is an n-channel MOSFET device. The source-drain path of trans...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G05F3/24
CPCG05F3/267G05F1/463G05F3/242
Inventor 刘永锋
Owner STMICROELECTRONICS (SHENZHEN) R&D CO LTD
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