partfinder:vreg
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partfinder:vreg [2012/04/08 17:38] gregham [Switching regulators] |
partfinder:vreg [2016/01/28 18:05] (current) |
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| - | Voltage regulators are used for turning input voltage to the desired output voltage to run a circuit off of. | + | Voltage regulators are used for providing a stable supply voltage, free of noise and AC ripple, to power a circuit. |
| Different types include: | Different types include: | ||
| - | * linear 'dropout' regulators: also called LDO regulators, these take a high voltage and create a 'dropout' to set the output to be some lower voltage. For example, 9V down to 5V the regulator creates a 4V drop. That drop is dissipated as heat. They are low cost, have varying input/output and dropout voltages as well as max current capability. | + | * Linear regulators: Starting with a higher than required input voltage, these provide a stable, lower output voltage. The regulator heats up as it dissipates the voltage drop times the current as heat. Low-dropout (LDO) versions can regulate their output voltage up to close to the input voltage, whereas regular ones require 2-3V headroom over and above the desired output voltage. Linear regulators are the lowest-cost types. |
| - | * switching regulators | + | |
| - | * DC/DC converters | + | |
| - | ====== Linear 'dropout' regulators ====== | + | * Switching regulators: These use a PWM approach to rapidly 'chop' or 'buck' the input voltage, which after smoothing provides a lower output voltage. These don't warm up as much because there is essentially no voltage drop in the regulator; it is either on or off, not somewhere in between. Switching regs can be small (many are surface-mount) and provide relatively high current for their size, but they do require a few external components to function. |
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| + | * DC/DC converters: This category includes step-up or 'boost' converters which can actually provide a higher output than the input voltage. These are similar in basic operation to the switching 'buck' converter just mentioned. Some are classified as buck-boost converters, meaning that they can provide an output of 5V (say) from an input of anywhere from 3V to 9V. Pretty handy stuff. | ||
| + | |||
| + | ====== Linear regulators ====== | ||
| ==== 78xx, 79xx ==== | ==== 78xx, 79xx ==== | ||
| - | The simplest and best known regulators are the 78xx and 79xx series, where xx is the desired output voltage. They have three pins: input, output and ground. 7805 will get you 5V on the output pin, as long as you supply an input voltage of at 2-3V higher. 79xx Series are for negative output voltages, but they work the same. | + | The simplest and best known regulators are the 78xx and 79xx series, where xx is the desired output voltage. They have three pins: input, output and ground. 7805 will get you 5V on the output pin, as long as you supply an input voltage of at least 2-3V more. 79xx Series are for negative output voltages, but they work the same. |
| These "building blocks" are great for making a simple and stable power supply. | These "building blocks" are great for making a simple and stable power supply. | ||
/home/ladyada/public_html/wiki/data/pages/partfinder/vreg.txt · Last modified: 2016/01/28 18:05 (external edit)
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