Zulular From the middle branch: Electronic circuits Analog circuits. There are several ways, but the main recipe is the following: All articles with dead external links Articles with dead external links from November Articles with permanently dead external links. Brokaw bandgap reference is a voltage reference circuit widely used in integrated circuits, with an output voltage around 1. This particular circuit is one type of a bandgap voltage reference, named after Paul Brokaw, the author of its first nandgap.
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Some thoughts about other dependencies What is a bandgap voltage reference? Many circuits, including voltage regulators , analog-digital and digital-analog converters, require a voltage reference that is as precise as possible. Their precision depends on it. That means that the voltage reference would ideally be PVT independent: P: manufacturing process variations V: supply voltage T: temperature Bandgap reference circuits cancel out two opposing variations caused by temperature.
Thus, let us review a bit the BJT. It is the bandgap voltage of silicon, the energy necessary to free an electron from the outer shell of the silicon atom.
It has the theoretical value of 1. But still If you ever see a voltage reference with a value close to 1. The next obvious question is: how do we implement this with real circuits? This is usually coped with by making the output dependent on a ratio of values pair of resistances, pair of BJTs, etc. Taking special care when laying out these devices, their values will be very similar during fabrication and depend very similarly on other parameters, such as temperature.
Power supply If you need a precision voltage reference, that means you do not have one already, right? So, the power supply to the reference will not be precise and the reference should be insensitive to it. The way to solve this is by differential circuits. In the bandgap examples, if the power supply changed, the currents of both branches would be affected equally. Therefore, the assumption of equal currents would still hold and effects of power supply variations would cancel at the output voltage.
Temperature Still, not every temperature dependent effects can be cancelled. References Lecture notes of Prof. It would mean the world to me!
Brokaw bandgap reference
The circuit output is the sum of the base—emitter voltage difference with one of the base—emitter voltages. This method enhanced further the curvature correction and achieved superior TD performance over a wider temperature range. Member feedback about Paul Brokaw: Because the regulated voltage of a linear regulator must always be lower than input voltage, efficiency is limited and the input voltage must be high enough to always allow the active device to drop some voltage. All articles with dead external links Articles with dead external links from November Articles with permanently dead external links. References Publications referenced by this paper.
Temperature Sensing with a Bandgap Reference
This temperature dependency has a typical parabolic residual behavior since the linear first brokaww effects are chosen to cancel. Power supply If you need a precision voltage reference, that means you do not have one already, right? Bandgap voltage reference What do you need to know to understand this topic? Member feedback about Paul Brokaw: Therefore, the assumption of equal currents would still hold and effects of power supply variations would cancel at the output voltage.