Band-gap reference circuit with photocurrent compensation
By designing a bandgap reference circuit with photocurrent compensation, the problem of unstable output voltage of traditional bandgap reference circuits under radiation is solved by using the photocurrent compensation circuit to cancel photocurrent interference, and voltage stability is achieved in a strong radiation environment.
Patent Information
- Application Number
- CN202511389732.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-26
- Publication Date
- 2025-11-18
AI Technical Summary
Traditional bandgap reference circuits are susceptible to photocurrent interference under strong X-ray and gamma-ray radiation, which can cause disturbances in the output reference voltage and affect system stability.
A bandgap reference circuit with photocurrent compensation was designed, which includes a bias current mirror, a bandgap reference pair, an error amplifier, an output adjustment transistor, a resistor sampling circuit, and a photocurrent compensation circuit. The photocurrent compensation circuit generates a compensation current at the voltage output terminal to cancel photocurrent interference.
Under strong X-ray and gamma-ray radiation, the output voltage of the bandgap reference circuit was stabilized, voltage disturbances were reduced, and the stability of the system under radiation environment was ensured.
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Figure CN120973173A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of analog circuit technology, and in particular to a bandgap reference circuit with photocurrent compensation. Background Technology
[0002] A bandgap reference circuit is a circuit that generates a stable reference voltage that is virtually independent of power supply voltage, process variations, and temperature changes. Its core principle is to compensate for the difference between two voltages / currents with opposite temperature coefficients, thereby obtaining a voltage with zero temperature coefficient. On a chip, the performance of almost all other circuit modules (such as ADCs, DACs, PLLs, and voltage regulators) depends on a high-quality reference voltage. If this reference voltage fluctuates with temperature or power supply fluctuations, the accuracy of the entire system will collapse. Therefore, the bandgap reference circuit is the "cornerstone" and "heart" of ensuring stable chip performance.
[0003] However, semiconductor devices generate strong photocurrents under special application environments (such as strong X-ray and gamma-ray radiation). These photocurrents can cause significant interference to the circuit, and in severe cases, can lead to permanent damage or latch-up of the device. Traditional bipolar bandgap reference circuits generally will not burn out or latch up under strong photocurrents, but the output reference voltage will experience significant disturbances, with the disturbance amplitude exceeding 10% or even dropping to zero, and will recover to stability after hundreds of microseconds or even milliseconds. This may cause instability in the entire system. Summary of the Invention
[0004] To address the shortcomings of the prior art, the technical problem to be solved by this invention is to provide a bandgap reference circuit with photocurrent compensation. Utilizing the photocurrent compensation circuit therein, a compensation current can be generated from the voltage output terminal under strong X-ray and gamma-ray pulse radiation, thereby compensating for output voltage disturbances caused by strong pulse radiation, and thus stabilizing the output voltage of the bandgap reference circuit under strong pulse radiation interference.
[0005] The technical solution adopted in this invention is as follows: A bandgap reference circuit with photocurrent compensation is provided, comprising a bandgap reference core and an error amplifier. The bandgap reference core includes a bias current mirror and a pair of bandgap reference transistors. The power supply is formed as the bias current of the pair of bandgap reference transistors through the bias current mirror. The error amplifier is used to further amplify the bandgap voltage error generated by the bandgap reference core, and further includes: An output adjustment transistor is connected to the output terminal of the error amplifier and is used to adjust the output voltage according to the error gain output by the error amplifier. A resistor sampling circuit, connected to the output terminal of the output adjustment transistor, is used to perform voltage division sampling on the output voltage and feed the sampled voltage back to the bandgap reference core; A current compensation circuit, connected to the output terminal of the output adjustment tube, is used to generate photocurrent and compensate the output voltage under X-ray or gamma-ray pulse radiation.
[0006] Furthermore, the bias current mirror is a Wilson current mirror, including transistors Q1, Q2, and Q3. The base of transistor Q1 is connected to the base of transistor Q2, and the emitters of both transistors Q1 and Q2 are connected to a power supply. The emitter of transistor Q3 is connected to the common base of transistors Q1 and Q2, the collector of transistor Q1 is connected to the emitter of transistor Q3, and the base of transistor Q3 is connected to the collector of transistor Q2.
[0007] Furthermore, the bandgap reference pair includes transistors Q4 and Q5, with the bases of transistors Q4 and Q5 connected to a common resistor R3; the collector of transistor Q3 is connected to the collector of transistor Q4, and the collector of transistor Q2 is connected to the collector of transistor Q5; the emitter of transistor Q4 is connected to a resistor R1, and the emitter of transistor Q5 is connected to a resistor R2; resistor R1 is connected in series with resistor R2, and resistor R2 is grounded.
[0008] Furthermore, the error amplifier includes transistors Q7 and Q8. The base of transistor Q7 is connected to the collector of transistor Q4 to amplify the bandgap voltage error generated by the bandgap reference core. The emitter of transistor Q7 is connected to the base of transistor Q8, thereby connecting transistors Q7 and Q8 to form a first Darlington composite transistor. The collectors of transistors Q7 and Q8 are connected. The emitter of transistor Q8 is connected to resistor R4, forming a common-emitter amplifier structure. Resistor R4 is connected to the base and collector of transistor Q9, and the emitter of transistor Q9 is grounded.
[0009] Furthermore, the error amplifier also includes a Miller compensation capacitor C1, which spans the base of transistor Q7 and the common junction of transistors Q7 and Q8 at their collectors.
[0010] Furthermore, the output regulating transistor includes a second Darlington composite transistor formed by connecting transistors Q10 and Q11. The base of transistor Q10 is connected to the common junction of transistors Q7 and Q8 at their collectors, which is used to enhance the output driving capability.
[0011] Furthermore, the output regulating transistor also includes a resistor R5 and a transistor Q12. The resistor R5 and the transistor Q12 form a current limiting circuit. One end of the resistor R5 is connected to the emitter of the transistor Q11 and the base of the transistor Q12, and the other end is connected to the output of the output regulating transistor. The emitter of the transistor Q12 is connected to the output of the output regulating transistor, and the collector of the transistor Q12 is connected to the emitter of the transistor Q10.
[0012] Furthermore, the resistor sampling circuit includes resistors R6 and R7. One end of resistor R6 is connected to the output of the output adjustment transistor, and the other end is connected to resistor R7. One end of resistor R7 is grounded. The voltage divider output terminal between resistors R6 and R7 is connected to the emitter of transistor Q8, which is used to introduce a feedback voltage to the error amplifier circuit.
[0013] Furthermore, the photocurrent compensation circuit includes a transistor Q13, the collector of which is connected to the output terminal of the output adjustment transistor through a resistor R9, the emitter of which is grounded, and the base of which is grounded through a resistor R8.
[0014] The present invention provides a bandgap reference circuit with photocurrent compensation, which has at least the following beneficial effects: by utilizing the photocurrent compensation circuit therein, a compensation current can be generated from the voltage output terminal under strong X-ray or gamma-ray pulse radiation, thereby compensating for the output voltage drift caused by illumination, and thus stabilizing the reference voltage output by the bandgap reference core under strong photocurrent interference environment. Attached Figure Description
[0015] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of a bandgap reference circuit with photocurrent compensation according to an embodiment of the present invention.
[0016] Figure 2 This is a voltage output waveform under strong gamma-ray pulse radiation in an embodiment of the present invention without a photocurrent compensation circuit.
[0017] Figure 3 This is a voltage output waveform under strong gamma-ray pulse radiation in an embodiment of the present invention with a photocurrent compensation circuit.
[0018] Explanation of reference numerals in the attached figures: Bandgap reference core-1; Error amplifier-2; Output adjustment transistor-3; Resistance sampling circuit-4; Photocurrent compensation circuit-5. Detailed Implementation
[0019] The invention will now be further described with reference to the accompanying drawings.
[0020] Please see Figure 1 This is a schematic diagram of the bandgap reference circuit with photocurrent compensation in this embodiment. The circuit includes a bandgap reference core 1, an error amplifier 2, an output adjustment transistor 3, a resistor sampling circuit 4, and a photocurrent compensation circuit 5.
[0021] The bias current mirror included in this bandgap reference core 1 is a Wilson current mirror, comprising transistors Q1, Q2, and Q3. The base of transistor Q1 is connected to the base of transistor Q2, and the emitters of both transistors Q1 and Q2 are connected to a power supply. The emitter of transistor Q3 is connected to the common base of transistors Q1 and Q2, the collector of transistor Q1 is connected to the emitter of transistor Q3, and the base of transistor Q3 is connected to the collector of transistor Q2.
[0022] The bandgap reference core 1 includes a bandgap reference pair of transistors Q4 and Q5, with an emitter area ratio of n:1. The bases of transistors Q4 and Q5 are connected to a common resistor R3. The collector of transistor Q3 is connected to the collector of transistor Q4, and the collector of transistor Q2 is connected to the collector of transistor Q5. The emitter of transistor Q4 is connected to a resistor R1, and the emitter of transistor Q5 is connected to a resistor R2. Resistor R1 is connected in series with resistor R2, and resistor R2 is grounded. Q1, Q2, and Q3 form a Wilson current mirror structure, providing equal bias current to Q4 and Q5.
[0023] In a bandgap reference pair of transistors, the emitter-junction voltage difference between transistors Q5 and Q4 can be expressed as: ,Right now:
[0024]
[0025]
[0026] The collector currents of transistors Q4 and Q5 are equal. , and Let be the reverse saturation current of Q4 and Q5. This current is proportional to the emitter area. The emitter area ratio of the two transistors is n:1. Therefore, .
[0027] therefore
[0028] Where k is Boltzmann constant, q is electron charge, T is absolute temperature, and V is V. TThis represents thermal voltage.
[0029] Voltage drop across resistor R1:
[0030] Preset bandgap voltage:
[0031] The bandgap reference core 1 generates a preset bandgap reference voltage, and the output voltage V sampled by the resistance sampling circuit 4 is... OUT The voltage divider generates an error through the bandgap reference core 1, which is further amplified by the error amplifier 2 to form negative feedback. The output voltage V is then stabilized by the output regulating transistor 3. OUT The output voltage is proportional to the bandgap reference.
[0032] Output voltage:
[0033]
[0034]
[0035] To eliminate the influence of the base current of transistor Q4, let:
[0036] Right now:
[0037] At this point, the output voltage can be obtained.
[0038]
[0039] Specifically, the bandgap reference core 1 includes a bias current mirror and a bandgap reference pair. The power supply is formed into a bias current equal to that of the bandgap reference pair through the bias current mirror; the bandgap reference pair extracts a temperature-positive bias current. Meanwhile, the error between the feedback voltage and the preset bandgap voltage is amplified by cascading common-emitter transistors Q5 and Q3.
[0040] This error amplifier 2 includes transistors Q7 and Q8. The base of transistor Q7 is connected to the collector of transistor Q4, and the emitter of transistor Q7 is connected to the base of transistor Q8, thus connecting transistors Q7 and Q8 to form a first Darlington composite transistor. The collectors of transistors Q7 and Q8 are connected to further amplify the bandgap voltage error generated by the bandgap reference core 1, forming negative feedback. The emitter of transistor Q8 is connected to resistor R4, forming a common-emitter amplifier structure. Resistor R4 is connected to the base and collector of transistor Q9, and the emitter of transistor Q9 is grounded.
[0041] The error amplifier 2 also includes a Miller compensation capacitor C1, which spans the base of transistor Q7 and the common junction of transistors Q7 and Q8 at their collectors.
[0042] Output adjustment tube 3 is connected to the output terminal of the error amplifier 2 and is used to adjust the output voltage according to the error gain output by the error amplifier 2. Specifically, the output regulating transistor 3 includes a second Darlington composite transistor formed by connecting transistors Q10 and Q11. The base of transistor Q10 is connected to the common junction of transistors Q7 and Q8 at their collectors, which is used to adjust the output voltage, enhance the output driving capability, and thus improve the output load capacity.
[0043] Meanwhile, the output regulating transistor 3 also includes a resistor R5 and a transistor Q12. The resistor R5 and the transistor Q12 form a current limiting circuit. One end of the resistor R5 is connected to the emitter of the transistor Q11 and the base of the transistor Q12, and the other end is connected to the output of the output regulating transistor 3. The emitter of the transistor Q12 is connected to the output of the output regulating transistor 3, and the collector of the transistor Q12 is connected to the emitter of the transistor Q10. The resistor R5 and the transistor Q12 form a current-limiting structure. The collector of transistor Q12 is connected to the base of transistor Q11 instead of the base of transistor Q10 because under strong X-ray or gamma-ray pulse radiation, both transistors Q10 and Q11 will generate strong instantaneous photocurrents. When the voltage across resistor R5 is higher than the emitter junction turn-on voltage of transistor Q12, if the collector of transistor Q12 is connected to the base of transistor Q10, it will affect the initial current of transistor Q10. The initial photocurrent will be discharged, and the initial photocurrent of transistor Q11 can still be amplified by Q11 to form a large secondary photocurrent, which cannot achieve the current limiting effect. However, the collector of transistor Q12 is connected to the base of transistor Q11. When the voltage across resistor R5 is higher than the conduction voltage of the emitter junction of transistor Q12, transistor Q12 will simultaneously discharge the secondary photocurrent of transistor Q10 and the initial photocurrent of transistor Q11. Under strong X-ray or gamma-ray pulse radiation, it can play the role of current limiting negative feedback.
[0044] The resistor sampling circuit 4 is connected to the output terminal of the output adjustment tube 3 and is used to perform voltage division sampling on the output voltage and feed the sampled voltage back to the bandgap reference core 1. Specifically, this resistor sampling circuit 4 includes resistors R6 and R7. One end of resistor R6 is connected to the output of the output adjustment transistor 3, and the other end is connected to resistor R7. One end of resistor R7 is grounded. The voltage divider output between resistors R6 and R7 is connected to the base of transistor Q5, used to introduce a feedback voltage to the bandgap reference core 1. This resistor sampling circuit 4 can obtain a voltage divider from the output voltage and amplify this voltage divider through the bandgap reference core 1 to feed it back to the error amplifier 2. The current compensation circuit 5 is connected to the output terminal of the output adjustment tube 3 and is used to generate photocurrent and compensate the output voltage under strong X-ray or γ-ray pulse radiation.
[0045] Specifically, the current compensation circuit 5 includes a transistor Q13. The collector of transistor Q13 is connected to the output terminal of the output regulating transistor 3 through a resistor R9. Its emitter is grounded, and its base is grounded through a resistor R8. Under normal conditions, transistor Q13 is in the off state, and the collector photocurrent is very small. Therefore, the compensation circuit does not work and has almost no effect on the output voltage. However, when subjected to strong X-ray or gamma-ray pulse radiation, an initial photocurrent is generated at the collector junction of transistor Q13. This photocurrent forms a voltage drop through resistor R8. When the voltage drop exceeds the turn-on voltage of transistor Q13, the emitter junction of transistor Q13 conducts, amplifying the portion of the initial photocurrent flowing into the emitter junction of transistor Q13. This forms a compensation current path from the voltage output terminal to ground, offsetting the influence of the photocurrent generated by the output regulating transistor 3 on the output voltage, thereby quickly maintaining the stability of the output voltage.
[0046] A pulse width of 25 ns and a dose rate of 3 × 10⁻⁶ were used. 8 A γ-ray pulse of Gy(Si) / s ± 10% irradiates both a bandgap reference circuit with and without photocurrent compensation circuit 5. The output voltage waveform of the bandgap reference circuit without photocurrent compensation is as follows: Figure 2 As shown, the output voltage of the bandgap reference circuit with photocurrent compensation is illustrated in the figure. Figure 3 .Depend on Figure 2 and Figure 3 The comparison shows that the output voltage disturbance of the bandgap reference circuit with photocurrent compensation is significantly lower than that of the example without current compensation circuit 5 under strong gamma-ray pulse radiation.
[0047] The above description merely illustrates preferred embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this invention should be determined by the appended claims.
Claims
1. A bandgap reference circuit with photo-current compensation, comprising a bandgap reference core and an error amplifier, the bandgap reference core comprising a bias current mirror and a bandgap reference pair, a supply current of the bandgap reference pair being formed through the bias current mirror; The error amplifier is used to amplify the bandgap voltage error generated by the bandgap reference core and output the error gain. It is characterized by further comprising: An output adjustment transistor is connected to the output terminal of the error amplifier and is used to adjust the output voltage according to the error gain output by the error amplifier. A resistor sampling circuit is connected to the output terminal of the output adjustment transistor. It is used to perform voltage division sampling on the output voltage and feed the sampled voltage back to the bandgap reference core. A photocurrent compensation circuit, connected to the output terminal of the output adjustment tube, is used to generate a photocurrent and compensate the output voltage under X-ray or gamma-ray pulse radiation.
2. The bandgap reference circuit with photo-current compensation as claimed in claim 1, wherein, The bias current mirror is a Wilson current mirror, comprising transistors Q1, Q2, and Q3. The base of transistor Q1 is connected to the base of transistor Q2, and the emitters of both transistors Q1 and Q2 are connected to a power supply. The emitter of transistor Q3 is connected to the common base of transistors Q1 and Q2, the collector of transistor Q1 is connected to the emitter of transistor Q3, and the base of transistor Q3 is connected to the collector of transistor Q2.
3. The bandgap reference circuit with photo-current compensation as claimed in claim 2, wherein, The bandgap reference pair includes resistors R1 and R2, transistors Q4 and Q5. The bases of transistors Q4 and Q5 are connected to resistor R3. The collector of transistor Q3 is connected to the collector of transistor Q4, and the collector of transistor Q2 is connected to the collector of transistor Q5. The emitter of transistor Q4 is connected to resistor R1, and the emitter of transistor Q5 is connected to resistor R2. Resistor R1 is connected in series with resistor R2, and resistor R2 is grounded.
4. The bandgap reference circuit with photo-current compensation as claimed in claim 3, wherein, The error amplifier includes transistors Q7 and Q8. The base of transistor Q7 is connected to the collector of transistor Q4 to amplify the bandgap voltage error generated by the bandgap reference core. The emitter of transistor Q7 is connected to the base of transistor Q8, thus connecting transistors Q7 and Q8 to form a first Darlington composite transistor. The collectors of transistors Q7 and Q8 are connected. The emitter of transistor Q8 is connected to resistor R4, forming a common-emitter amplifier structure. Resistor R4 is connected to the base and collector of transistor Q9, and the emitter of transistor Q9 is grounded.
5. The bandgap reference circuit with photo-current compensation as claimed in claim 4, wherein, The error amplifier also includes a Miller compensation capacitor C1, which is connected across the base of transistor Q7 and the common junction of transistors Q7 and Q8 at their collectors.
6. The bandgap reference circuit with photocurrent compensation as described in claim 4, characterized in that, The output adjustment transistor includes a second Darlington composite transistor formed by connecting transistors Q10 and Q11. The base of transistor Q10 is connected to the common junction of transistors Q7 and Q8 at the collector, which is used to enhance the output drive capability.
7. The bandgap reference circuit with photocurrent compensation as described in claim 6, characterized in that, The output regulating transistor also includes a resistor R5 and a transistor Q12. The resistor R5 and the transistor Q12 form a current limiting circuit. One end of the resistor R5 is connected to the emitter of the transistor Q11 and the base of the transistor Q12, and the other end is connected to the output of the output regulating transistor. The emitter of the transistor Q12 is connected to the output of the output regulating transistor, and the collector of the transistor Q12 is connected to the emitter of the transistor Q10.
8. The bandgap reference circuit with photocurrent compensation as described in claim 6, characterized in that, The resistance sampling circuit includes resistors R6 and R7. One end of resistor R6 is connected to the output of the output adjustment transistor, and the other end is connected to resistor R7. One end of resistor R7 is grounded. The voltage divider output between resistors R6 and R7 is connected to the base of transistor Q5 to introduce a feedback voltage to the bandgap reference core 1.
9. The bandgap reference circuit with photocurrent compensation as described in claim 8, characterized in that, The photocurrent compensation circuit includes resistors R8 and R9 and transistor Q13. The collector of transistor Q13 is connected to the output terminal of the output adjustment transistor through resistor R9, its emitter is grounded, and its base is grounded through resistor R8.