## Voltage Reference - From Diode To High Precision High Order BandGap

Amplifier 20 has a gain of A 1. As shown, temperature dependent current I t , produced in multiple copies by current mirror 22 , flows through each of transistors Q 1 -Q 4. The ratio of the resistances of R 2 to R 1 provides the gain. Thus, there is need for less gain. One embodiment of the present invention is adding second-order temperature coefficient or curvature correction to the bandgap cell of FIG.

However, it should be appreciated that the currents flowing through resistors R 1 and R 2 have to remain temperature-dependent PTAT in order to achieve the first-order correction. As shown, the cell includes amplifier 20 , positive temperature coefficient current generator 24 and negative temperature coefficient current generator As stated, the currents in transistors Q 1 and Q 4 must be temperature-dependent in order to produce the first-order temperature correction.

There is, however, more freedom to choose temperature coefficients of the currents flowing through transistors Q 2 and Q 3 , so as to produce the desired second-order correction. This non-linearity will offset the non-linearity in the base emitter voltage V be of transistor Q 1. With appropriate selection of parameters, the two non-linearities can be made to be equal and opposite such that they will eliminate one another, thereby producing an output voltage VBG, which will be first- and second-order invariant with temperature.

As shown, the cell includes amplifier 20 and current sources 30 and By contrast with the cell shown in FIG. I 0 is a temperature-independent constant current. Current source 30 produces I 0 plus I t , while current source 32 products I 0 minus I t. The use of temperature-dependent current I t is convenient because it already is used in the bandgap cell for first-order correction. It otherwise operates similarly to the cell shown and described in FIG.

The cell of FIG. The bandgap cell shown in FIG. The cell includes amplifiers [] 20 and 21 , having respective gains of A 1 and A 2. A basic stacked bandgap cell includes transistors Q 1 -Q 4 , amplifier 20 and transistors M 9 -M Temperature-compensated output voltage VBG is the base emitter voltage V be of resistor Q 1 added to the voltage across resistor R 2.

That voltage, across resistor R 2 , is a scaled copy of the voltage provided across resistor R 1. That voltage is predominantly temperature-dependent, but has a second-order non-linearity that cancels the second-order non-linearity in the base emitter voltage V be of transistor Q 1. Making the quiescent currents of transistors Q 2 and Q 3 have significantly different temperature coefficients produces that non-linearity.

In the embodiment shown in FIG. This constant current, copied by current mirrors comprised of elements M 13 -M 17 , is supplied to transistors Q 2 and Q 3. The temperature-dependent currents I t are produced in the bandgap cell itself and flow through transistors Q 4 and Q 1. Thus, the temperature coefficient of current flowing through Q 3 is more positive than that of current flowing through Q 2 , producing the non-linearity which will cancel that of the V be.

M 17 is a transistor, arranged as a diode, that, with M 14 and M 15 , acts as a current mirror. It copies current I 0 in transistors M 14 and M This is added to temperature-independent current I 0 before flowing through transistor Q 3. The cell shown in FIG. In silicon-based technologies, this voltage may be on the order of approximately 1. In many applications, however, a larger temperature stabilized voltage is desirable. Curvature correction is accomplished, as described with respect to FIG. As stated, twice the base emitter voltage is utilized, and is produced by adding the base emitter voltages of transistors Q [] 1 and Q 3. Also, in comparison to FIG.

In addition, unlike FIG. Having thus described at least one illustrative embodiment of the invention, various alterations, modifications and improvements will readily occur to those skilled in the art.

Such alterations, modifications and improvements are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description is by way of example only and is not intended as limiting. The invention is limited only as defined in the following claims and the equivalents thereto. What is claimed is: 1. A method of producing a temperature-compensated reference voltage comprising steps of: providing a stacked bandgap cell including at least four bipolar elements; and.

The method as claimed in claim 1 wherein each of the at least four elements is a diode. In a commonplace arrangement, a single resistor and Zener diode create a simple voltage rail.

Design of Bandgap voltage reference (BGR) - 9 : BGR with opamp

To maintain accuracy, you must choose a low-enough value of series-resistor value to ensure that the Zener reverse-bias current I z falls within an acceptable range. This may be as high as 5 mA, especially with lower-cost, non-temperature-compensated diodes Fig. As an example, with a V input, using a 2. A voltage reference also called a band-gap reference provides the same functionality as a Zener diode, yet requires far less current to maintain a more-accurate voltage. While a Zener diode uses a single p-n junction with specific doping to create a Zener breakdown voltage, a voltage reference uses a combination of transistors and employs a positive-temperature-coefficient p-n junction in conjunction with negative-temperature-coefficient transistors to make a zero-temperature-coefficient reference.

The concept and design of a band-gap reference was introduced back in the s by Bob Widlar, when he was a power IC designer.

## Voltage References: From Diodes to Precision High-Order Bandgap Circuits

Using a voltage reference in place of a Zener diode is about efficiency and simplicity. The TI LM 2. As shown in Fig. Be sure to use the worst-case load current and take tolerances into account when selecting this resistor. Calculate R s to accommodate the worst-case load current while maintaining the minimum Zener current. The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Effective date : Year of fee payment : 4. Embodiments of the present invention include systems and methods for generating a curvature compensated bandgap voltage reference. In an embodiment, a curvature compensated bandgap reference voltage is achieved by injecting a temperature dependent current at different points in the bandgap reference voltage circuit. Field of the Invention The present invention relates generally to bandgap voltage reference circuits.

Background Art A bandgap voltage reference circuit is a circuit that generates a reference voltage called bandgap voltage reference with low temperature dependence. Example Temperature Dependent Current Sinking Circuits As described above, one component of a curvature correction circuit according to embodiments of the present invention is a temperature dependent current sinking circuit, which operates by sinking a pre-determined current when the circuit temperature exceeds a pre-determined temperature.

Conclusion It is to be appreciated that the Detailed Description section, and not the Summary and Abstract sections, is intended to be used to interpret the claims. A bandgap voltage reference circuit, comprising: a current generation stage configured to generate a proportional to absolute temperature PTAT current and a complementary to absolute temperature CTAT current;.

• Download Voltage References From Diodes To Precision High Order Bandgap Circuits 2001.
• Religious Experience Reconsidered: A Building-Block Approach to the Study of Religion and Other Special Things?

The bandgap voltage reference circuit of claim 1 , wherein the curvature correction circuit comprises a plurality of temperature dependent current sinking circuits, wherein each of the temperature dependent current sinking circuits is configured to generate a respective current when temperature exceeds a respective temperature trip point.

The bandgap voltage reference circuit of claim 2 , wherein the curvature correction circuit comprises a temperature-independent current source, wherein the temperature-independent current source is configured to generate a current proportional to the CTAT current. The bandgap voltage reference circuit of claim 3 , wherein the curvature correction current is proportional to the sum of the currents generated by the plurality of temperature dependent current sinking circuits and the current generated by the temperature-independent current source.

The bandgap voltage reference circuit of claim 4 , wherein the current generated by the temperature-independent current source has a negative temperature coefficient, and wherein the currents generated by the temperature dependent current sinking circuits have positive temperature coefficients.

The bandgap voltage reference circuit of claim 2 , wherein each of the plurality of temperature dependent current sinking circuits comprises a temperature trip point monitoring circuit. The bandgap voltage reference circuit of claim 1 , wherein a temperature coefficient of the curvature correction current increases with temperature. The bandgap voltage reference circuit of claim 1 , wherein a temperature coefficient of the curvature correction current is approximately opposite to a temperature coefficient of the bandgap voltage reference over temperature.

The bandgap voltage reference circuit of claim 1 , wherein the curvature correction current varies according to a linear piecewise continuous function versus temperature. The bandgap voltage reference circuit of claim 1 , wherein the curvature-compensated bandgap voltage reference is substantially independent of temperature. A method for generating a curvature-compensated bandgap voltage reference in a bandgap voltage reference circuit, comprising: generating a proportional to absolute temperature PTAT current and a complementary to absolute temperature CTAT current;. The method of claim 11 , wherein generating the curvature correction current comprises generating a current proportional to the CTAT current.

The method of claim 12 , wherein generating the curvature correction current comprises generating a plurality of currents having positive temperature coefficients, and wherein each of the plurality of currents takes a non-zero value when temperature exceeds a respective temperature trip point.

• Voltage References Diodes Precision High Order by Gabriel Alfonso Rincon Mora - AbeBooks;
• Management in Social Work!
• Voltage Reference - From Diode To High Precision High Order BandGap.
• The Seleucid Army: Organization and Tactics in the Great Campaigns?

The method of claim 13 , wherein the curvature correction current is proportional to the sum of the current proportional to the CTAT current and the plurality of currents. The method of claim 11 , wherein a temperature coefficient of the curvature correction current increases with temperature. The method of claim 11 , wherein a temperature coefficient of the curvature correction current is approximately opposite to a temperature coefficient of the bandgap voltage reference over temperature.

## Voltage References: From Diodes to Precision High-Order Bandgap Circuits

The method of claim 11 , wherein the curvature correction current varies according to a linear piecewise continuous function versus temperature. The method of claim 11 , wherein the curvature-compensated voltage reference is substantially independent of temperature. USP true USB2 en.

Bandgap voltage reference circuit, system, and method for reduced output curvature. Reference voltage source and method for providing a curvature-compensated reference voltage. JPB2 en. Reference circuit with curvature correction using additional complementary to temperature component. Reference voltage generating circuit and method for providing reference voltages.

USB1 en. Bandgap reference voltage source circuit having a high-order temperature compensation. Programmable temperature coefficient analog second-order curvature compensated voltage reference and trim techniques for voltage reference circuits. Programmable temperature coefficient analog second-order curvature compensated voltage reference. Apparatus and method for compensating change in a temperature associated with a host device. Andy, Jonathan M. Avoinne, C. Azarkan, Ahmidou et al. Chen, Jianghua et al. Dai, Xin, et al. ISCAS , p.

## Voltage References : From Diodes to Precision High Order Bandgap Circuits - ocuryvodix.tk

He, Jun, et al. Hoon, Siew Kuok et al. VV, Jiang, Yueming et al. IVIV, May , Jun, Cheng et al. Ker, Ming-Dou et al. Qin, Bo et al. Rincon-Mora, Gabriel et al. Solid-State Circuits, vol. Salminen, O. Spady, David et al. II, Wang, Haibo et al. Xing, Xinpeng et al. Ying, Song et al. Zongmin, Wang et al. USA1 en. Band-gap reference circuit for providing an accurate reference voltage compensated for process state, process variations and temperature. Bandgap voltage reference using differential pairs to perform temperature curvature compensation.