CN103699171B - There is the bandgap current circuit structure of high stability - Google Patents

Abstract

The present invention relates to a kind of bandgap current circuit structure with high stability, described circuit structure comprises a NPN triode and the 2nd NPN triode of composition mirror-image constant flow source, the collector resistance R of a NPN triode and the 2nd NPN triode _cresistance be resistance R between collector and base stage _cb90 to 110 times, thus under circuit basic structure and the constant prerequisite of process conditions, effectively reduce the collector resistance R of NPN triode _c, thus can reduce the impact of NPN triode saturation voltage drop, and then ensure the stability of energy gap reference current, and the bandgap current circuit structure with high stability of the present invention is simple, realize with low cost, range of application is also comparatively extensive.

Description

There is the bandgap current circuit structure of high stability

Technical field

The present invention relates to circuit structure technical field, particularly bandgap current circuit technical field of structures, specifically refer to a kind of bandgap current circuit structure with high stability.

Background technology

The schematic diagram of bandgap current generating circuit of the prior art, as shown in Figure 1, its derivation is as follows:

∵ $I_{Q11294}=I_{Q11293},I=I_S\×(e^{\frac{U_{BE}}{U_T}}-1)\≈I_S\×e^{\frac{U_{BE}}{U_T}},$

U _BE(Q11293)＝U _BE(Q11294)+I×R _X11492，S _e(Q11294)＝6×S _e(Q11293)

∴ $6\×I_S\×e^{\frac{U_{BE\left(Q11294\right)}}{U_T}}=I_S\×e^{\frac{U_{BE\left(Q11293\right)}}{U_T}}=I_S\×e^{\frac{U_{BE\left(Q11294\right)}+I\×R_{X11492}}{U_T}}$

∴I×R _X11492＝U _T×ln 6

∴ $I=\frac{U_T\×ln6}{R_{X11492}}$

In theory, bandgap electric current only depends on resistance R _x11492resistance, with other factors have nothing to do, substitute into resistance value can calculate energy gap electric current.According to sample circuit extraction parameter out, bandgap current simulations result is illustrated in fig. 2 shown below.Due to NPN pipe collector resistance R in process modeling _cbigger than normal, make NPN pipe saturation voltage drop bigger than normal, make bandgap electric current excessive in the interval amplitude of oscillation of normal working voltage, thus cause integrated circuit quiescent current bigger than normal.

Quiescent current simulation result and the sample circuit measured value of integrated circuit contrast then as shown in Figure 3.As seen from Figure 3, power supply scans from 0 ~ 10V, interval at circuit normal working voltage 6.5 ~ 9.5V, according to existing realistic model (NPN model qvn2d2x2d2ba), energy gap current reference profile slope is excessive, make overall quiescent current increase with the increase of voltage too fast, cause the normal operating power consumption of integrated circuit excessive.So, improvement must be made to bandgap current circuit.

Summary of the invention

The object of the invention is to overcome above-mentioned shortcoming of the prior art, a kind of impact that can effectively reduce NPN triode saturation voltage drop is provided, and then ensure the stability of energy gap reference current, and structure is simple, realize with low cost, range of application has the bandgap current circuit structure of high stability comparatively widely.

In order to realize above-mentioned object, the bandgap current circuit structure with high stability of the present invention has following formation:

This circuit structure comprises a NPN triode Q1 of composition mirror-image constant flow source, 2nd NPN triode Q2 and energy gap resistance R1, a described NPN triode Q1 and the 2nd NPN triode Q2 is identical triode, the base stage of the 2nd NPN triode Q2 described in base stage connection of a described NPN triode Q1, the base stage of a described NPN triode Q1 also connects the collector of a NPN triode Q1, the collector of a described NPN triode Q1 is connected power supply by a triode with pull-up resistor, the emitter of a described NPN triode Q1 is by a pull down resistor ground connection, the emitter of the 2nd described NPN triode Q2 is by described energy gap resistance R1 and described pull down resistor ground connection, the current collection very constant current source output terminal of the 2nd described NPN triode Q2, and the collector resistance R of a described NPN triode Q1 _cresistance be resistance R between its collector and base stage _cb90 to 110 times, the collector resistance R of the 2nd described NPN triode Q2 _cresistance be resistance R between its collector and base stage _cb90 to 110 times.

This has in the bandgap current circuit structure of high stability, the collector resistance R of a described NPN triode Q1 _cresistance be resistance R between its collector and base stage _cb101.25 times, the collector resistance R of the 2nd described NPN triode Q2 _cresistance be resistance R between its collector and base stage _cb101.25 times.

This has in the bandgap current circuit structure of high stability, and a described NPN triode Q1 and the 2nd NPN triode Q2 has the P type body Rotating fields of alternative P type substrate.

This has in the bandgap current circuit structure of high stability, and the Standard resistance range of described energy gap resistance R1 is 1.7K Ω to 2K Ω.

Have employed the bandgap current circuit structure with high stability of this invention, wherein.Composition the one NPN triode Q1 of mirror-image constant flow source and the collector resistance R of the 2nd NPN triode Q2 _cresistance be resistance R between collector and base stage _cb90 to 110 times, effectively reduce the collector resistance R of NPN triode _c, thus can reduce the impact of NPN triode saturation voltage drop, and then ensure the stability of energy gap reference current, and the bandgap current circuit structure with high stability of the present invention is simple, realize with low cost, range of application is also comparatively extensive.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of bandgap current generating circuit of the prior art.

The bandgap current simulations result schematic diagram that Fig. 2 is circuit shown in Fig. 1.

Fig. 3 is integrated circuit quiescent current simulation result and sample circuit measured value comparison diagram.

Fig. 4 is the circuit diagram with the bandgap current circuit structure of high stability of the present invention.

Fig. 5 is the result schematic diagram that two kinds of NPN triode models carry out concrete emulation.

The quiescent current IV curve synoptic diagram that Fig. 6 is the simulation result shown in Fig. 5 and sample circuit comparing result.

Fig. 7 is the result schematic diagram of the emulation of increase energy gap resistance of the present invention.

The quiescent current IV curve synoptic diagram that Fig. 8 is the simulation result shown in Fig. 7 and sample circuit comparing result.

Embodiment

In order to more clearly understand technology contents of the present invention, describe in detail especially exemplified by following examples.

Referring to shown in Fig. 4, is the circuit diagram with the bandgap current circuit structure of high stability of the present invention.

In one embodiment, this bandgap current circuit structure with high stability comprises composition the one NPN triode Q1, the 2nd NPN triode Q2 of mirror-image constant flow source and energy gap resistance R1, a described NPN triode Q1 and the 2nd NPN triode Q2 are identical triode.The base stage of the 2nd NPN triode Q2 described in base stage connection of a described NPN triode Q1, the base stage of a described NPN triode Q1 also connects the collector of a NPN triode Q1, the collector of a described NPN triode Q1 is connected power supply by a triode with pull-up resistor, the emitter of a described NPN triode Q1 is by a pull down resistor ground connection, the emitter of the 2nd described NPN triode Q2 is by described energy gap resistance R1 and described pull down resistor ground connection, the current collection very constant current source output terminal of the 2nd described NPN triode Q2, and the collector resistance R of a NPN triode Q1 _cresistance be resistance R between its collector and base stage _cb90 to 110 times, the collector resistance (R of the 2nd described NPN triode (Q2) _c) resistance be resistance (R between its collector and base stage _cb) 90 to 110 times.Wherein, a described NPN triode Q1 and the 2nd NPN triode Q2 has the P type body Rotating fields of alternative P type substrate.

In a preferred embodiment, the collector resistance R of a described NPN triode Q1 _cresistance be resistance R between its collector and base stage _cb101.25 times, the collector resistance (R of the 2nd described NPN triode (Q2) _c) resistance be resistance (R between its collector and base stage _cb) 101.25 times.

In preferred embodiment, the Standard resistance range of described energy gap resistance R1 is 1.7K Ω to 2K Ω.

In actual applications, of the present invention have in the bandgap current circuit structure of high stability, will determine the collector resistance R of the NPN pipe of bandgap electric current _creduce, reduce its saturation voltage drop, thus reduce its impact on bandgap current swing.The simplest method directly changes the conventional process model of NPN pipe Q1 and Q2 into qvn2d2x2d2bd from qvn2d2x2d2ba.

Concrete model parameter comparison is as follows:

	R cb	R c
			Model qvn2d2x2d2ba	1	678.38×R cb
Model qvn2d2x2d2bd	1	101.25×R cb

The collector resistance R of the NPN triode of table 1 two models _cparameter comparison table

The difference of technique lithographic layer time two models in aspect is:

The process ration table of the NPN triode of table 2 two models

From table 2, technique changes device model and only need reduce partially over mask level of once making a plate and can realize, simultaneously also can not increase plate-making cost.

For adopting above-mentioned two kinds of NPN triode models to carry out the result of concrete emulation as shown in Figure 5, wherein: the corresponding model qvn2d2x2d2ba of solid line, the corresponding model qvn2d2x2d2bd of dotted line.

From the above-mentioned emulation shown in Fig. 6 and comparing result, power supply is from 0 ~ 10V scanning, interval at normal working voltage 6.5-9.5V, adopts the bandgap current curve slope of new model milder, reduces the amplitude of oscillation of energy gap electric current; Integrated circuit quiescent current rate of curve also surveys circuit with sample consistent, and this should be the result of the design philosophy meeting primary circuit.And in operating voltage interval, the bandgap current value of employing new model and theoretical value error, within 2uA, meet the requirement of bandgap current stabilization.

But, new model quiescent current and sample are surveyed and contrasts, still there is the situation of about 10% bigger than normal.Then by forcing down the method for bandgap electric current, namely can increase the resistance about 10% of resistance X11492, overall quiescent current ICC is reduced, final emulation and actual measurement correlation curve are as shown in Figure 7.Wherein, the corresponding model qvn2d2x2d2ba of solid line, the corresponding model qvn2d2x2d2bd of dotted line, dotted line is qvn2d2x2d2bd model and increases resistance X11492 resistance.

As shown in Figure 8, between the normal operation interval 6.5-9.5V of circuit, bandgap current curve slope is mild, remains within error range, meet the requirement of bandgap current stabilization with theoretical value; Curve and the sample measured curve of final matching are simultaneously basically identical, ensure that quiescent current and the power consumption of integrated circuit.Thus achieve a kind of utilization and reduce NPN collector resistance R _cresistance, the impact of NPN saturation voltage drop on bandgap electric current is reduced relatively, thus under circuit basic structure and the constant prerequisite of process conditions, achieves the bandgap characteristic of expection, greatly facilitate the smooth research and development of circuit, improve the compatibility of technique.

Have employed the bandgap current circuit structure with high stability of this invention.Wherein, a NPN triode Q1 of mirror-image constant flow source and the collector resistance R of the 2nd NPN triode Q2 is formed _cresistance be resistance R between collector and base stage _cb90 to 110 times, effectively reduce the collector resistance R of NPN triode _c, thus can reduce the impact of NPN triode saturation voltage drop, and then ensure the stability of energy gap reference current, and the bandgap current circuit structure with high stability of the present invention is simple, realize with low cost, range of application is also comparatively extensive.

In this description, the present invention is described with reference to its specific embodiment.But, still can make various amendment and conversion obviously and not deviate from the spirit and scope of the present invention.Therefore, instructions and accompanying drawing are regarded in an illustrative, rather than a restrictive.

Claims (4)

1. one kind has the bandgap current circuit structure of high stability, described circuit structure comprises a NPN triode (Q1) of composition mirror-image constant flow source, 2nd NPN triode (Q2) and energy gap resistance (R1), a described NPN triode (Q1) is identical triode with the 2nd NPN triode (Q2), the base stage of the 2nd NPN triode (Q2) described in base stage connection of a described NPN triode (Q1), the base stage of a described NPN triode (Q1) also connects the collector of a NPN triode (Q1), the collector of a described NPN triode (Q1) is connected power supply by a triode with pull-up resistor, the emitter of a described NPN triode (Q1) is by a pull down resistor ground connection, the emitter of the 2nd described NPN triode (Q2) is by described energy gap resistance (R1) and described pull down resistor ground connection, the current collection very constant current source output terminal of the 2nd described NPN triode (Q2), it is characterized in that, collector resistance (the R of a described NPN triode (Q1) _c) resistance be resistance (R between its collector and base stage _cb) 90 to 110 times, the collector resistance (R of the 2nd described NPN triode (Q2) _c) resistance be resistance (R between its collector and base stage _cb) 90 to 110 times.

2. the bandgap current circuit structure with high stability according to claim 1, is characterized in that, the collector resistance (R of a described NPN triode (Q1) _c) resistance be resistance (R between its collector and base stage _cb) 101.25 times, the collector resistance (R of the 2nd described NPN triode (Q2) _c) resistance be resistance (R between its collector and base stage _cb) 101.25 times.

3. the bandgap current circuit structure with high stability according to claim 1 and 2, it is characterized in that, a described NPN triode (Q1) and the 2nd NPN triode (Q2) have the P type body Rotating fields of alternative P type substrate.

4. the bandgap current circuit structure with high stability according to claim 3, is characterized in that, the Standard resistance range of described energy gap resistance (R1) is 1.7K Ω to 2K Ω.