CN116301152A - A Reference Circuit Structure for Ultra-Low Voltage Output - Google Patents

Abstract

The invention provides a reference circuit structure for ultralow voltage output, which comprises a starting circuit, wherein the output end of the starting circuit is respectively connected with a PTAT current generating circuit and a reference voltage generating circuit; the output end of the PTAT current generation circuit is connected with a reference voltage generation circuit; the starting circuit is used for establishing a starting working point, and the PTAT current generation circuit comprises a proportional constant current source circuit which is used for generating a current proportional to absolute temperature and mirroring the current to a reference voltage generation circuit; the reference voltage generating circuit is used for outputting a low-voltage reference; the input power supply voltage of the reference circuit structure is lower than 1.65V, the reference voltage can be as low as 500mV, and is far lower than the band gap reference voltage in the prior art, and the reference circuit structure is suitable for low-voltage and low-power consumption LDO systems; the requirement of a low-voltage and low-power consumption linear voltage stabilizer can be met.

Description

A Reference Circuit Structure for Ultra-Low Voltage Output

technical field

The invention belongs to the technical field of power supply management, and in particular relates to a reference circuit structure for ultra-low voltage output.

Background technique

With the miniaturization of semiconductor device size and continuous updating of technology, power supply chips have also developed by leaps and bounds. Low voltage and low power consumption have become an important standard for current circuit design. More and more linear regulators need to operate at a power supply voltage of 1.65V, or even lower voltage; the output voltage of the bandgap reference circuit in the prior art is usually about 1.25V, which limits the minimum power supply voltage for the circuit to work, and is not suitable for the operation of the input power supply voltage below 1.65V low voltage linear regulator.

As shown in Figure 1, it is a traditional bandgap reference circuit structure, which consists of amplifier A1, resistors R1, R2 and R3, and NPN transistors Q1 and Q2. The negative end of the amplifier A1 is connected to one end of the resistor R2 and the resistor R3, the positive end of the amplifier A1 is connected to one end of the resistor R1 and the collector of the NPN transistor Q1, the output end of the amplifier A1 is VREF; the other end of the resistor R1 is connected to the resistor R2 The other end of the resistor R3 is connected to VIN; the other end of the resistor R3 is connected to the collector of the NPN transistor Q2; the base of the NPN transistor Q1 is connected to the collector, the base of the NPN transistor Q2 is connected to the collector, and the emitter of the NPN transistor Q1 is connected to the NPN transistor The emitter of Q2 is connected to the ground level GND, which has the following disadvantages: first, the traditional bandgap reference operating voltage must be at least 3V to work normally; second, the output reference voltage is 1.25V, which cannot meet the low-voltage input linear regulation device needs.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a reference circuit structure for ultra-low voltage output, which solves the problem that the reference module works normally and outputs a reference voltage with zero temperature coefficient when the low-voltage power supply is supplied.

The present invention is achieved through the following technical solutions:

A reference circuit structure for ultra-low voltage output, including a start-up circuit, the output ends of the start-up circuit are respectively connected to a PTAT current generation circuit and a reference voltage generation circuit; the output end of the PTAT current generation circuit is connected to a reference voltage generation circuit;

The starting circuit is used to establish an initial operating point, and the PTAT current generating circuit includes a proportional constant current source circuit for generating a current proportional to the absolute temperature, and mirroring the current to a reference voltage generating circuit; the reference The voltage generation circuit is used to output a low voltage reference.

Preferably, the start-up circuit includes a power supply Vin, the power supply Vin is connected to one end of a parallel resistor R1, resistor R2, resistor R3, resistor R4 and resistor R5, and the other end of the resistor R1 is connected to the emitter of the PNP transistor Q1, The other end of the resistor R2 is connected to the emitter of the PNP transistor Q2, the other end of the resistor R3 is connected to the emitter of the PNP transistor Q4, the other end of the resistor R4 is connected to the emitter of the PNP transistor Q4, and the other end of the resistor R5 is connected to the PNP transistor The emitter of tube Q5;

The PNP transistor Q1, PNP transistor Q2, PNP transistor Q3, PNP transistor Q4 and PNP transistor Q5 form a constant current source circuit.

Preferably, the collector of the PNP transistor Q1 is connected to the external signal VBIAS1, the base of the PNP transistor Q1, the base of the PNP transistor Q2, the base of the PNP transistor Q3, the base of the PNP transistor Q4, and the base of the PNP transistor Q5. pole.

Preferably, the PTAT current generation circuit includes a proportional constant current source circuit, a PNP transistor Q8 and a PNP transistor Q10, the collector of the PNP transistor Q1 is connected to the base of the PNP transistor Q8, and the output terminal of the PNP transistor Q8 is connected to the proportional constant current source circuit output terminal, and access to the emitter of the NPN transistor Q10.

Preferably, the base of the NPN transistor Q10 is connected to the signal VBIAS2.

Preferably, the proportional constant current source circuit includes a PNP transistor Q6, a PNP transistor Q7, a resistor R6, a resistor R7 and a resistor R10, the collector of the PNP transistor Q2 is connected to the collector of the PNP transistor Q6 and the collector of the PNP transistor Q8, and the PNP The collector of the tube Q3 is connected to the collector of the PNP tube Q7, one end of the resistor R7 and one end of the resistor R6; the base of the NPN tube Q6 is connected to the other end of the resistor R6, and the emitter of the NPN tube Q6 is connected to one end of the resistor R10, The collector of the NPN transistor Q10 and the emitter of the NPN transistor Q8, the base of the NPN transistor Q7 is connected to the other end of the resistor R7, and the emitter of the NPN transistor Q7 is connected to the other end of the resistor R10; the base of the NPN transistor Q10 Signal VBIAS2 is connected.

Preferably, the collector and the emitter of the PNP transistor Q6 are respectively connected to both ends of the capacitor C1.

Preferably, the ratio of the emitter areas of Q6:Q7 of the PNP transistor Q6 and the PNP transistor Q7 is 1:n, wherein n is a positive integer.

Preferably, the reference voltage generating circuit includes a resistor R8, a resistor R9 and an NPN transistor Q9, the collector of the PNP transistor Q4 is connected to one end of the resistor R8, the collector and the base of the NPN transistor Q9; the collector of the PNP transistor Q5 Connect the other end of the resistor R8, the other end of the resistor R9, and the signal VREF.

倍的带隙基准。Preferably, the output voltage of the reference voltage generation circuit is numerically

times the bandgap reference.

Compared with the prior art, the present invention has the following beneficial technical effects:

The invention provides a reference circuit structure for ultra-low voltage output, including a start-up circuit, the output ends of the start-up circuit are respectively connected to a PTAT current generation circuit and a reference voltage generation circuit; the output end of the PTAT current generation circuit is connected to a reference voltage generation circuit circuit; the starting circuit is used to establish an initial operating point, and the PTAT current generating circuit includes a proportional constant current source circuit for generating a current proportional to the absolute temperature, and mirroring the current to the reference voltage generating circuit; The reference voltage generating circuit is used to output a low-voltage reference; the reference circuit structure of the present application has an input power supply voltage lower than 1.65V, and the reference voltage can be as low as 500mV, which is far lower than the bandgap reference voltage in the prior art, and is suitable for low-voltage , LDO system with low power consumption; it can meet the needs of low-voltage, low-power linear regulators.

Description of drawings

Fig. 1 is a structural diagram of a bandgap reference circuit in the prior art;

Fig. 2 is a structure diagram of a reference circuit for ultra-low voltage output in the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with specific embodiments, which are explanations of the present invention rather than limitations.

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

The present invention provides a reference circuit structure for ultra-low voltage output, as shown in Figure 2, comprising a start-up circuit, the output ends of the start-up circuit are respectively connected to a PTAT current generation circuit and a reference voltage generation circuit; the PTAT current generation circuit The output terminal is connected to the reference voltage generating circuit;

The starting circuit is used to establish an initial operating point, and the PTAT current generating circuit includes a proportional constant current source circuit for generating a current proportional to the absolute temperature, and mirroring the current to a reference voltage generating circuit; the reference The voltage generation circuit is used to output a low voltage reference.

Preferably, the start-up circuit includes a power supply Vin, the power supply Vin is connected to one end of a parallel resistor R1, resistor R2, resistor R3, resistor R4 and resistor R5, and the other end of the resistor R1 is connected to the emitter of the PNP transistor Q1, The other end of the resistor R2 is connected to the emitter of the PNP transistor Q2, the other end of the resistor R3 is connected to the emitter of the PNP transistor Q4, the other end of the resistor R4 is connected to the emitter of the PNP transistor Q4, and the other end of the resistor R5 is connected to the PNP transistor The emitter of the tube Q5; the PNP tube Q1, PNP tube Q2, PNP tube Q3, PNP tube Q4 and PNP tube Q5 form a constant current source circuit, which is used to provide stable current to ensure stable operation of other circuits.

Preferably, the collector of the PNP transistor Q1 is connected to the external signal VBIAS1, the base of the PNP transistor Q1, the base of the PNP transistor Q2, the base of the PNP transistor Q3, the base of the PNP transistor Q4, and the base of the PNP transistor Q5. pole; the external signal VBIAS1 is a bias voltage.

Preferably, the PTAT current generation circuit includes a proportional constant current source circuit, a PNP transistor Q8 and a PNP transistor Q10, the collector of the PNP transistor Q1 is connected to the base of the PNP transistor Q8, and the output terminal of the PNP transistor Q8 is connected to the proportional constant current source circuit output terminal, and access to the emitter of the NPN transistor Q10.

Preferably, the base of the NPN transistor Q10 is connected to the signal VBIAS2, and the external signal VBIAS2 is a bias voltage.

Preferably, the proportional constant current source circuit includes a PNP transistor Q6, a PNP transistor Q7, a resistor R6, a resistor R7 and a resistor R10, the collector of the PNP transistor Q2 is connected to the collector of the PNP transistor Q6 and the collector of the PNP transistor Q8, and the PNP The collector of the tube Q3 is connected to the collector of the PNP tube Q7, one end of the resistor R7 and one end of the resistor R6; the base of the NPN tube Q6 is connected to the other end of the resistor R6, and the emitter of the NPN tube Q6 is connected to one end of the resistor R10, The collector of the NPN transistor Q10 and the emitter of the NPN transistor Q8, the base of the NPN transistor Q7 is connected to the other end of the resistor R7, and the emitter of the NPN transistor Q7 is connected to the other end of the resistor R10; the base of the NPN transistor Q10 Signal VBIAS2 is connected.

Preferably, the collector and the emitter of the PNP transistor Q6 are respectively connected to both ends of a capacitor C1, specifically, the capacitor C1 is a filter capacitor.

Preferably, the ratio of the emitter areas of Q6:Q7 of the PNP transistor Q6 and the PNP transistor Q7 is 1:n, wherein n is a positive integer.

Preferably, the reference voltage generating circuit includes a resistor R8, a resistor R9 and an NPN transistor Q9, the collector of the PNP transistor Q4 is connected to one end of the resistor R8, the collector and the base of the NPN transistor Q9; the collector of the PNP transistor Q5 Connect the other end of the resistor R8, the other end of the resistor R9, and the signal VREF.

倍的带隙基准。Preferably, the output voltage of the reference voltage generation circuit is numerically

times the bandgap reference.

The present invention will be described in further detail below in conjunction with accompanying drawings and examples.

After the circuit is powered on, start the internal constant current sources Q1~Q5 to establish a static working point;

The generation of PTAT current in the PTAT current generation circuit is composed of proportional pair tubes composed of Q6 and Q7. The ratio of the emitter area of Q6:Q7 is 1:n, where n is a positive integer. The analysis results are as follows:

V _BE6 = V _BE7 + I _REF R ₁₀ (1);

V _BE6 -V _BE7 = I _REF R ₁₀ can be obtained, then

Since I _C6 =I _C7 , nI _S6 =I _S7 , the PTAT current is obtained:

From the above formula, the value of R ₁₀ determines the size of the PTAT current;

V _REF =V _BE9 -I ₁ R ₈ =I ₂ R ₉ (4);

I _REF +I ₁ =I ₂ (5);

Therefore,

Available,

finally available

Among them, I _C6 represents the collector current of Q6, I _C7 represents the collector current of Q7, I _S6 represents the emitter current of Q6, I _S7 represents the emitter current of Q7, I ₁ represents the current flowing through R ₈ , I ₂ is the current flowing through _R9 , I _REF is the PTAT current, V _REF is the output reference voltage, V _BE6 is the base-emitter voltage of Q6, V _BE7 is the base-emitter voltage of Q7, V _T is Thermal voltage, lnn is the logarithm of n.

倍的带隙基准，能提供传统带隙基准不能提供的超低基准电压。By adjusting the resistance values of R8, R9, R10 and the ratio n of the emitter areas of Q7 and Q6 by those skilled in the art, the circuit can output an ultra-low voltage reference voltage with an approximate zero temperature coefficient, as can be seen from formula (8) , the output voltage is numerically

times the bandgap reference, it can provide an ultra-low reference voltage that cannot be provided by traditional bandgap references.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it still The technical solutions described in the foregoing embodiments can be modified, or some or all of the technical features can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. The reference circuit structure for ultralow voltage output is characterized by comprising a starting circuit, wherein the output end of the starting circuit is respectively connected with a PTAT current generating circuit and a reference voltage generating circuit; the output end of the PTAT current generation circuit is connected with a reference voltage generation circuit;

the starting circuit is used for establishing a starting working point, and the PTAT current generation circuit comprises a proportional constant current source circuit which is used for generating a current proportional to absolute temperature and mirroring the current to a reference voltage generation circuit; the reference voltage generating circuit is used for outputting a low-voltage reference.

2. The reference circuit structure of the ultra-low voltage output according to claim 1, wherein the starting circuit comprises a power supply Vin, the power supply Vin is connected with one ends of a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a resistor R5 which are connected in parallel, the other end of the resistor R1 is connected with an emitter of a PNP tube Q1, the other end of the resistor R2 is connected with an emitter of the PNP tube Q2, the other end of the resistor R3 is connected with an emitter of the PNP tube Q4, the other end of the resistor R4 is connected with an emitter of the PNP tube Q4, and the other end of the resistor R5 is connected with an emitter of the PNP tube Q5;

the PNP tube Q1, the PNP tube Q2, the PNP tube Q3, the PNP tube Q4 and the PNP tube Q5 form a constant current source circuit.

3. The reference circuit structure of claim 2, wherein the collector of the PNP transistor Q1 is connected to an external signal VBIAS1, a base of the PNP transistor Q2, a base of the PNP transistor Q3, a base of the PNP transistor Q4, and a base of the PNP transistor Q5.

4. The reference circuit structure for ultra-low voltage output according to claim 2, wherein the PTAT current generating circuit comprises a proportional constant current source circuit, a PNP transistor Q8 and a PNP transistor Q10, wherein the collector of the PNP transistor Q1 is connected to the base of the PNP transistor Q8, and the output end of the PNP transistor Q8 is connected to the output end of the proportional constant current source circuit and is connected to the emitter of the NPN transistor Q10.

5. The reference circuit structure for ultra-low voltage output according to claim 4, wherein the base of NPN transistor Q10 is connected to signal VBIAS2.

6. The reference circuit structure for ultra-low voltage output according to claim 4, wherein the proportional constant current source circuit comprises a PNP transistor Q6, a PNP transistor Q7, a resistor R6, a resistor R7 and a resistor R10, wherein a collector of the PNP transistor Q2 is connected to a collector of the PNP transistor Q6 and a collector of the PNP transistor Q8, and a collector of the PNP transistor Q3 is connected to a collector of the PNP transistor Q7, one end of the resistor R7 and one end of the resistor R6; the base of the NPN tube Q6 is connected with the other end of the resistor R6, the emitter of the NPN tube Q6 is connected with one end of the resistor R10, the collector of the NPN tube Q10 and the emitter of the NPN tube Q8, the base of the NPN tube Q7 is connected with the other end of the resistor R7, and the emitter of the NPN tube Q7 is connected with the other end of the resistor R10; the base of NPN pipe Q10 is connected with signal VBIAS2.

7. The reference circuit structure for ultra-low voltage output according to claim 4, wherein the collector and emitter of the PNP transistor Q6 are further connected to two ends of the capacitor C1, respectively.

8. The reference circuit structure for ultra-low voltage output according to claim 4, wherein Q6 of said PNP transistor Q6 and PNP transistor Q7: the ratio of emitter areas of Q7 is 1: n, where n is a positive integer.

9. The reference circuit structure of ultralow voltage output according to claim 2, wherein the reference voltage generating circuit comprises a resistor R8, a resistor R9 and an NPN tube Q9, and the collector of the PNP tube Q4 is connected with one end of the resistor R8, the collector and the base of the NPN tube Q9; the collector of the PNP tube Q5 is connected with the other end of the resistor R8, the other end of the resistor R9 and the signal VREF.

10. The reference circuit structure for ultra-low voltage output according to claim 9, wherein the output voltage of said reference voltage generating circuit is numerically

A multiple band gap reference.

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