Current generator circuit for generating substantially constant current

A current generator circuit for generating a substantially constant reference current which includes a bandgap reference circuit comprising:

• an operational amplifier having first and second inputs receiving signals respectively from intermediate nodes of first and second resistive chains, each resistive chain having in series a first terminal connected to a first potential, a unidirectional current control element, at least one resistive element and a second terminal, the second terminals of the resistive chains being connected at a junction node;
• the operational amplifier having an output for supplying an output signal to a control terminal of an output device which has a controllable path connected between a power supply voltage and said junction node of said first and second resistive chains, the current generator circuit further comprising:
• a current setting device which receives at a control terminal thereof the output signal of the operational amplifier and which has its controllable path connected between said power supply voltage and a current supply terminal to provide at said current supply terminal a substantially constant reference current;
• wherein the resistive elements are selected to have a variation in resistance with temperature matched to the variation in base emitter voltage of the transistors in each resistive chain to maintain a feedback current supplied by said output device to said junction node substantially constant, said resistive elements being formed as n-well diffusions.

A current generator circuit for generating a substantially constant reference current which includes a bandgap reference circuit comprising:

• an operational amplifier having first and second inputs receiving signals respectively from intermediate nodes of first and second resistive chains, each resistive chain having in series a first terminal connected to a first potential, a unidirectional current control element, at least one resistive element and a second terminal, the second terminals of the resistive chains being connected at a junction node;
• the operational amplifier having an output for supplying an output signal to a control terminal of an output device which has a controllable path connected between a power supply voltage and said junction node of said first and second resistive chains, the current generator circuit further comprising:
• a current setting device which receives at a control terminal thereof the output signal of the operational amplifier and which has its controllable path connected between said power supply voltage and a current supply terminal to provide at said current supply terminal a substantially constant reference current;
• wherein the resistive elements are selected to have a variation in resistance with temperature matched to the variation in base emitter voltage of the transistors in each resistive chain to maintain a feedback current supplied by said output device to said junction node substantially constant, said resistive elements being formed as p-well diffusions.

An integrated circuit comprising:

• an array of reprogrammable memory cells;
• decode circuitry associated with said array;
• and
• a current generator circuit for generating a substantially constant reference current which includes a bandgap reference circuit comprising:
• an operational amplifier having first and second inputs receiving signals respectively from intermediate nodes of first and second resistive chains, each resistive chain having in series a first terminal connected to a first potential, a unidirectional current control element, at least one resistive element and a second terminal, the second terminals of the resistive chains being connected at a junction node;
• the operational amplifier having an output for supplying an output signal to a control terminal of an output device which has a controllable path connected between a power supply voltage and said junction node of said first and second resistive chains, the current generator circuit further comprising:
• a current setting device which receives at a control terminal thereof the output signal of the operational amplifier and which has its controllable path connected between said power supply voltage and a current supply terminal to provide at said current supply terminal a substantially constant reference current.