CN-121996018-A - Band gap reference circuit

CN121996018ACN 121996018 ACN121996018 ACN 121996018ACN-121996018-A

Abstract

The invention discloses a band gap reference circuit which comprises a starting module, a voltage sampling and feedback module, a band gap reference core module, a negative feedback loop of the band gap reference core module and a UVLO module, wherein the voltage sampling and feedback module and the UVLO module multiplex part of the negative feedback loop, the starting module is used for providing starting current and bias voltage, the voltage sampling and feedback module is used for sampling input voltage to obtain the input sampling voltage, the feedback voltage is output to the band gap reference core module through the negative feedback loop, the band gap reference core module is used for establishing a normal working point under the triggering of the starting current and generating stable band gap reference voltage based on the control of the negative feedback loop, and the UVLO module is used for detecting the input sampling voltage according to the band gap reference voltage and outputting a digital logic level signal according to the detection result to realize the under-voltage locking function. The circuit has higher integration level and low power consumption.

Inventors

ZHOU YAO
WANG JING
FAN DAWEI
YU LIMING

Assignees

上海朔集半导体科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260327

Claims (15)

1. The band gap reference circuit is characterized by comprising a starting module, a voltage sampling and feedback module, a band gap reference core module, a negative feedback loop of the band gap reference core module and a UVLO module, wherein the voltage sampling and feedback module and the UVLO module multiplex part of the negative feedback loop; The starting module is used for providing starting current for the band gap reference core module, providing a first bias voltage for the UVLO module and providing a second bias voltage for the voltage sampling and feedback module; the voltage sampling and feedback module is used for sampling input voltage to obtain input sampling voltage, and outputting feedback voltage to the band gap reference core module through the negative feedback loop; the band gap reference core module is used for establishing a normal working point under the triggering of the starting current and generating stable band gap reference voltage based on the control of the negative feedback loop; And the UVLO module is used for detecting the voltage of the input sampling voltage according to the band gap reference voltage and outputting a digital logic level signal according to a detection result so as to realize the under-voltage locking function.
2. The bandgap reference circuit according to claim 1, wherein said bandgap reference core module comprises a first current mirror, a core unit and a voltage transmission unit; The first current mirror is used for mirroring the starting current to obtain a first current and a second current; the core unit comprises a pair of transistors consisting of a first transistor and a second transistor and an emitter resistor network; The first transistor and the second transistor generate negative temperature coefficient voltages in response to the first current and the second current, respectively, and form voltage differences having positive temperature coefficients based on different current densities; the emitter resistor network is connected to the emitter paths of the first transistor and the second transistor and is used for generating a compensating voltage with a positive temperature coefficient in the emitter path of the second transistor based on the voltage difference with the positive temperature coefficient; The base electrodes of the first transistor and the second transistor are connected and serve as the output end of the band-gap reference core module to output the band-gap reference voltage; the voltage transmission unit is used for forming the negative feedback loop with the voltage sampling and feedback module and part of circuits of the UVLO module.
3. The bandgap reference circuit according to claim 2, wherein said first current mirror comprises two MOS transistors of the same type, said two MOS transistors of the same type having the same aspect ratio, forming a 1:1 ratio current mirror structure.
4. The bandgap reference circuit according to claim 2, wherein said first transistor and said second transistor are bipolar transistors.
5. The bandgap reference circuit according to claim 2, wherein said emitter resistor network comprises a first resistor and a second resistor, said first resistor being connected between an emitter of said first transistor and a first node, said second resistor being connected between said first node and ground, an emitter of said second transistor being connected to said first node.
6. The bandgap reference circuit according to claim 2, wherein said emitter resistor network comprises a third resistor connected between the emitter of said first transistor and ground and a fourth resistor connected between the emitter of said second transistor and ground.
7. The bandgap reference circuit according to claim 1, wherein said start-up module comprises: a signal generating unit for generating the start-up current, the first bias voltage and the second bias voltage; a current mirror unit for providing a current transmission path to transmit the start-up current to the bandgap reference core module; And the control unit is used for switching off the current transmission path when the band gap reference voltage reaches a set value.
8. The bandgap reference circuit of claim 7, wherein said UVLO module comprises a PMOS tube and an NMOS tube, wherein a source of said PMOS tube is connected to said input sampling voltage, a gate of said PMOS tube is connected to a source, a drain of said PMOS tube is connected to a drain of said NMOS tube, a source of said NMOS tube is grounded, and a gate of said NMOS tube is connected to said first bias voltage.
9. The bandgap reference circuit according to claim 8, wherein said circuit further comprises: and the UVLO hysteresis module is used for introducing positive feedback and providing an internal reference threshold value for voltage detection of the UVLO module, wherein the internal reference threshold value comprises a rising opening threshold value and a falling closing threshold value.
10. The bandgap reference circuit according to claim 9, wherein said UVLO hysteresis module comprises a bias current source and a hysteresis switch; The bias current source is used for receiving the first bias voltage and providing constant current; And the hysteresis switch is used for switching the constant current path according to the on or off of the digital logic level signal so as to output the internal reference threshold value.
11. The bandgap reference circuit of claim 10, wherein said bias current source and said hysteresis switch are NMOS transistors.
12. The bandgap reference circuit of claim 10, wherein said voltage sampling and feedback module, said UVLO module and said UVLO hysteresis module are integrated in the same module.
13. The bandgap reference circuit according to any of claims 1 to 12, characterized in that the circuit further comprises a level shift module, and/or an inverter; The level shifting module is used for carrying out level shifting and waveform shaping on the digital logic level signal output by the UVLO module; and the inverter is used for inverting the digital logic level signal output by the UVLO module.
14. The bandgap reference circuit according to claim 13, wherein said level conversion module comprises an NMOS transistor and a ground resistor, wherein the gate and drain of said NMOS transistor are interconnected to form a diode connection, the drain of said NMOS transistor is connected to said digital logic level signal, the source of said NMOS transistor is grounded via said ground resistor, and the source of said NMOS transistor outputs a converted voltage; The input end of the inverter is connected to the source electrode of the NMOS tube and is used for receiving the conversion voltage and shaping the conversion voltage so as to output an enabling control signal.
15. The bandgap reference circuit according to any of claims 1 to 12, wherein said circuit further comprises: The starting and pre-voltage stabilizing module is used for accessing an external power supply, clamping the input voltage at a low level and realizing a pre-voltage stabilizing function.

Description

Band gap reference circuit Technical Field The invention relates to the technical field of circuits, in particular to a band gap reference circuit. Background Bandgap references (Bandgap Reference, BGR) are an essential component of integrated circuit design that can generate a reference voltage that is almost independent of temperature, supply voltage, and process. With the development of integrated circuit technology, higher requirements are put on the characteristics of bandgap reference, such as area, power consumption and power supply rejection ratio (Power Supply Rejection Ratio, PSRR). The undervoltage lock (Under Voltage Lock Out, UVLO) is a function which is added frequently in circuit design and is used for ensuring that the system is in a normal working state only when the power supply is higher than the UVLO threshold value and is in a protection state when the power supply is lower than the minimum working voltage, and the UVLO circuit with lower power consumption and smaller area is designed to have higher engineering significance. The traditional UVLO adopts the divided voltage of the input voltage as the comparison voltage, and judges whether the system is under voltage or not after the comparison of the comparator and the band gap reference voltage. While this approach effectively protects the circuit, the voltage dividing legs and comparators increase area and power consumption, even though the current of the voltage dividing legs and comparators increases power consumption when the system is stationary. Disclosure of Invention The embodiment of the invention provides a band gap reference circuit, which is used for improving the integration level and PSRR performance and reducing the power consumption. The embodiment of the invention provides a band gap reference circuit, which comprises a starting module, a voltage sampling and feedback module, a band gap reference core module, a negative feedback loop of the band gap reference core module and a UVLO module, wherein the voltage sampling and feedback module and the UVLO module multiplex part of the negative feedback loop; The starting module is used for providing starting current for the band gap reference core module, providing a first bias voltage for the UVLO module and providing a second bias voltage for the voltage sampling and feedback module; the voltage sampling and feedback module is used for sampling input voltage to obtain input sampling voltage, and outputting feedback voltage to the band gap reference core module through the negative feedback loop; the band gap reference core module is used for establishing a normal working point under the triggering of the starting current and generating stable band gap reference voltage based on the control of the negative feedback loop; And the UVLO module is used for detecting the voltage of the input sampling voltage according to the band gap reference voltage and outputting a digital logic level signal according to a detection result so as to realize the under-voltage locking function. Optionally, the bandgap reference core module comprises a first current mirror, a core unit and a voltage transmission unit; The first current mirror is used for mirroring the starting current to obtain a first current and a second current; the core unit comprises a pair of transistors consisting of a first transistor and a second transistor and an emitter resistor network; The first transistor and the second transistor generate negative temperature coefficient voltages in response to the first current and the second current, respectively, and form voltage differences having positive temperature coefficients based on different current densities; the emitter resistor network is connected to the emitter paths of the first transistor and the second transistor and is used for generating a compensating voltage with a positive temperature coefficient in the emitter path of the second transistor based on the voltage difference with the positive temperature coefficient; The base electrodes of the first transistor and the second transistor are connected and serve as the output end of the band-gap reference core module to output the band-gap reference voltage; the voltage transmission unit is used for forming the negative feedback loop with the voltage sampling and feedback module and part of circuits of the UVLO module. Optionally, the first current mirror comprises two MOS tubes of the same type, wherein the two MOS tubes of the same type have the same width-to-length ratio, and a current mirror structure with the proportion of 1:1 is formed. Optionally, the first transistor and the second transistor are bipolar transistors. Optionally, the emitter resistor network comprises a first resistor and a second resistor, wherein the first resistor is connected between an emitter of the first transistor and a first node, the second resistor is connected between the first node and ground, and the emitter of the second tran