EP-4741984-A1 - A BANDGAP REFERENCE CIRCUIT

EP4741984A1EP 4741984 A1EP4741984 A1EP 4741984A1EP-4741984-A1

Abstract

A bandgap reference circuit comprising: a proportional to absolute temperature, PTAT, voltage circuit configured to generate a PTAT voltage; and a bandgap voltage circuit comprising a diode, the bandgap voltage circuit configured to: receive the PTAT voltage from the PTAT voltage circuit; and combine the PTAT voltage with a diode voltage across the diode to output a bandgap reference voltage.

Inventors

SHERIGAR, ARVIND

Assignees

NXP B.V.

Dates

Publication Date: 20260513
Application Date: 20250113

Claims (15)

A bandgap reference circuit comprising: a proportional to absolute temperature, PTAT, voltage circuit configured to generate a PTAT voltage; and a bandgap voltage circuit comprising a diode, the bandgap voltage circuit configured to: receive the PTAT voltage from the PTAT voltage circuit; and combine the PTAT voltage with a diode voltage across the diode to output a bandgap reference voltage.
The bandgap reference circuit of claim 1, wherein the bandgap voltage circuit comprises: a bandgap voltage node configured to output the bandgap reference voltage; and a tail voltage node configured to be set to the PTAT voltage, wherein an anode of the diode is connected to the bandgap voltage node and a cathode of the diode is connected to the tail voltage node.
The bandgap reference circuit of claim 2, wherein the bandgap voltage circuit comprises: a regulating transistor with a source terminal coupled to a supply voltage node and a drain terminal connected to the bandgap voltage node; an input circuit coupled to the PTAT voltage circuit and configured to set the tail voltage node to the PTAT voltage; and a current mirror output transistor with a conduction channel connected between the tail voltage node and a reference voltage node.
The bandgap reference circuit of claim 3, wherein the input circuit comprises: a first input transistor, wherein a source terminal of the first input transistor is connected to the supply node and a drain terminal of the first input transistor is connected to a gate terminal of the regulating transistor; and a second input transistor, wherein a drain terminal of the second input transistor is connected to the gate terminal of the regulating transistor and a source terminal of the second input transistor is connected to the tail voltage node.
The bandgap reference circuit of any of claims 2 to 4, wherein the bandgap reference circuit comprises an output circuit connected between the bandgap voltage node and a reference node, wherein the output circuit is configured to provide a constant current through the output circuit from the bandgap voltage node to the reference node.
The bandgap reference circuit of claim 5, wherein the output circuit comprises an output resistance circuit.
The bandgap reference circuit of claim 5, wherein the output circuit comprises a current sink.
The bandgap reference circuit of any of claims 5 to 7, when dependent on claims 3 or 4, wherein the current mirror output transistor is configured to pull a constant current through the regulating transistor that is equal to the constant current provided through the output circuit.
The bandgap reference circuit of claim 8, wherein the bandgap reference circuit comprises an output current reference transistor configured to mirror the constant current from the regulating transistor to a constant current output terminal.
The bandgap reference circuit of any of claims 5 to 9, wherein the bandgap reference circuit comprise a balancing current transistor, wherein: a source terminal of the balancing current transistor is connected to the supply voltage node; and a drain terminal of the balancing current transistor is connected to the bandgap voltage node.
The bandgap reference circuit of claim 10, when dependent on claim 3 or claim 4, wherein: the input circuit is configured to mirror a first PTAT current from the PTAT voltage circuit; the balancing current transistor is configured to mirror a second PTAT current from the PTAT voltage circuit; and the current mirror output transistor is configured to mirror a third PTAT current from the PTAT voltage circuit equal to a sum of the first PTAT current and the second PTAT current.
The bandgap reference circuit of claim 11, wherein the first PTAT current equals the second PTAT current.
The bandgap reference circuit of any preceding claim, wherein the PTAT voltage circuit comprises: a PTAT core comprising a first resistor and configured to generate a PTAT current through the first resistor; and an intermediate current mirror branch comprising a second resistor and configured to mirror the PTAT current from the PTAT core through the second resistor to generate the PTAT voltage.
The bandgap reference circuit of claim 13, wherein a resistance of the second resistor is greater than a resistance of the first resistor.
An automotive transceiver comprising the bandgap reference circuit of any preceding claim.

Description

Field The present disclosure relates to a bandgap reference circuit. Summary According to a first aspect of the present disclosure there is provided a bandgap reference circuit comprising: a proportional to absolute temperature, PTAT, voltage circuit configured to generate a PTAT voltage; anda bandgap voltage circuit comprising a diode, the bandgap voltage circuit configured to: receive the PTAT voltage from the PTAT voltage circuit; andcombine the PTAT voltage with a diode voltage across the diode to output a bandgap reference voltage. In one or more embodiments, the bandgap voltage circuit may comprise: a bandgap voltage node configured to output the bandgap reference voltage; anda tail voltage node configured to be set to the PTAT voltage,wherein an anode of the diode is connected to the bandgap voltage node and a cathode of the diode is connected to the tail voltage node. In one or more embodiments, the bandgap voltage circuit may comprise: a regulating transistor with a source terminal coupled to a supply voltage node and a drain terminal connected to the bandgap voltage node;an input circuit coupled to the PTAT voltage circuit and configured to set the tail voltage node to the PTAT voltage; anda current mirror output transistor with a conduction channel connected between the tail voltage node and a reference voltage node. [the PTAT voltage circuit is configured to generate the PTAT voltage from a supply voltage received at the supply voltage node; and] In one or more embodiments, the input circuit may comprise: a first input transistor, wherein a source terminal of the first input transistor is connected to the supply node and a drain terminal of the first input transistor is connected to a gate terminal of the regulating transistor; anda second input transistor, wherein a drain terminal of the second input transistor is connected to the gate terminal of the regulating transistor and a source terminal of the second input transistor is connected to the tail voltage node. The first and second input transistor may form an output of a current mirror. The input circuit may mirror a PTAT current from the PTAT voltage circuit. The input circuit may mirror the PTAT voltage from the PTAT voltage circuit to the tail voltage node. A gate terminal of each of the first and second input transistors may be connected to a respective terminal of the PTAT voltage circuit. The regulating transistor, the diode and the first and second input transistors may form a regulation loop. The regulation loop may regulate a current through the regulating transistor to regulate the bandgap reference voltage at the bandgap voltage node. The regulation loop may regulate the bandgap reference voltage to the sum of the PTAT voltage and the diode voltage. In one or more embodiments, the bandgap reference circuit may comprise an output circuit connected between the bandgap voltage node and a reference node, wherein the output circuit is configured to provide a constant current through the output circuit from the bandgap voltage node to the reference node. In one or more embodiments, the output circuit may comprise an output resistance circuit. The output resistance circuit may comprise a plurality of resistors. In one or more embodiments, wherein the output circuit may comprise a current sink. In one or more embodiments, the current mirror output transistor may be configured to pull a constant current through the regulating transistor that is equal to the constant current provided through the output circuit. The current mirror output transistor is configured to mirror a multiple of a PTAT current from the PTAT voltage circuit to provide the constant current through the regulating transistor. In one or more embodiments, the bandgap reference circuit may comprise an output current reference transistor configured to mirror the constant current from the regulating transistor to a constant current output terminal. In one or more embodiments, the bandgap reference circuit may comprise a balancing current transistor, wherein: a source terminal of the balancing current transistor is connected to the supply voltage node; anda drain terminal of the balancing current transistor is connected to the bandgap voltage node. The balancing current transistor may mirror a PTAT current from the PTAT voltage circuit. A gate terminal of the balancing current transistor may be coupled to the PTAT voltage circuit. In one or more embodiments: the input circuit may be configured to mirror a first PTAT current from the PTAT voltage circuit;the balancing current transistor is configured to mirror a second PTAT current from the PTAT voltage circuit; andthe current mirror output transistor is configured to mirror a third PTAT current from the PTAT voltage circuit equal to a sum of the first PTAT current and the second PTAT current. In one or more embodiments, the first PTAT current may equal the second PTAT current. The balancing current transistor may mirror the sec