Temperature insensitive bandgap voltage generator tracking power supply variations

A circuit for generating a bandgap voltage comprising:

• two resistors connected between a first potential and a second potential for providing a reference voltage from between said two resistors so that the reference voltage is dependent on the first potential and is substantially independent of temperature variations;
• a pair of bipolar transistors having a common collector connected to the first potential and having bases connected between said two resistors for receiving the reference voltage;
• a first resistor connected in series with an emitter of a first of said bipolar transistors for generating a voltage/current temperature coefficient thereacross;
• an amplifier having a first terminal connected to said first resistor, a second terminal connected to an emitter of a second of said bipolar transistors for sensing a difference therebetween, and an output connected between the first potential and a lower second potential;
• a second resistor connected in series with an emitter of the second of said bipolar transistors, said second resistor being tapped for providing a bandgap voltage;
• and
• a feedback loop for providing an output from said amplifier to said first and second resistors, said feedback loop comprising a current mirror for providing proportional currents to said first and second resistors, and plural series connected field effect transistors connected between said amplifier and said current mirror for enabling high output impedance operation of said current mirror.

A bandgap generator comprising:

• an amplifier with a feedback loop having a high impedance output current mirror controlled by transistors connected to an output from said amplifier,
• said current mirror for providing proportional currents to a pair of resistors that are connected to inputs to said amplifier,
• a first of said inputs for receiving a temperature sensitive voltage from a first resistor,
• a second of said inputs for receiving a voltage that is a combination of a voltage across a second of said resistors and an offsetting voltage for cancelling a temperature variation in an output from said second resistor,
• said second resistor having a tap for a bandgap voltage;
• and
• a reference circuit for providing a reference voltage which is dependent on a voltage from a power supply, the reference voltage for connecting said first and second resistors to the power supply.

A bandgap voltage generator for providing a bandgap voltage to a semiconductor circuit which tracks a power supply voltage, the generator comprising:

• a reference voltage circuit comprising two transistors which are operated by a reference voltage, and two similar resistors connected to divide a power supply voltage for providing the reference voltage from between said two similar resistors so that the reference voltage is dependent on the power supply voltage and is substantially independent of temperature variations;
• a first resistor for providing a first temperature sensitive voltage, and a second resistor for providing a second temperature insensitive voltage, said first and second resistors connected to receive the power supply voltage though said two transistors;
• an amplifier circuit for providing a difference between the first and second voltages;
• and
• a feedback loop for providing an output from said amplifier to said second resistor to make the second voltage insensitive to temperature, whereby the bandgap voltage tracks the power supply voltage and is available at said second resistor.