LM317 power board voltage regulator board with protection 2.2A 1.25V-37V DC power continuously adjustable plate LM317
This section LM317 adjustable DC power supply board , increase the heat sink , for a big adjustment potentiometer , AC / DC can be input , input voltage range :3-40V, with load protection, which can be accessed below 2.2A load , 1.25V-37V continuously adjustable , wide range of applications .
◆ The board core components : adjustable regulator ASIC LM317, 2.2A or less able to take the load can be AC or DC voltage input, maximum input voltage: AC / DC 3-40V, output voltage range: 1.25V-37V DC continuous adjustable ; increase the load circuit protection circuit load protection. Is a rare wide range of uses DC power board.
The following is the output voltage regulation when the input AC 15V get :
Production adjustable power supply with LM317T, often due to poor contact potentiometer output voltage increases and burned the load. If you increase a transistor , under normal circumstances, the base potential of the transistor is 0 , the transistor is turned off, no effect on the circuit ; And when the potentiometer is bad, the base potential of the transistor rises , when rose 0.7v, the transistor conduction, will be adjusted to reduce the terminal voltage LM317T , the output voltage is reduced , and thus the load protection. We use a small bulb 3.8V to do experiments, such as the transistor removed , disconnect the center potentiometer connection , a small bulb burned immediately , the measured output voltages up to 21V. When the transistor plus a small bulb brightness reducing , when the output voltage is only LM317T 2V, thus effectively protecting the load.
◆ LM117/LM317 Description:
· LM117/LM317 is National Semiconductor three-terminal adjustable positive voltage regulator IC , our country and the world's major IC manufacturers have similar products are available , is to use a very broad class of integrated voltage regulators series devices .
· Output voltage range LM117/LM317 is l.25V to 37V, load current up to 2.2A. Its use is very simple, only two external resistors to set the output voltage. In addition to its line regulation and load regulation are better than standard fixed regulators. LM117/LM317 variety of protection circuits built overload protection, safe area protection.
· Typically LM117/LM317 external capacitors are unnecessary unless the input filter capacitor to the input connection LM117/LM317 than 6 inches ( about 15 cm ) . Use the output capacitance change transient response. Adjusted using the filter capacitor terminal to get than standard three- terminal regulator much higher ripple rejection ratio.
· LMll7/LM317 There are many special usage. For example, to adjust the suspension to end on a high voltage , can be used to adjust the voltage up to hundreds of volts , as long as the input and output pressure does not exceed the limit LM117/LM317 on the line . Of course, but also to avoid output short circuit . It can also be adjusted on a programmable voltage end to achieve programmable power output.
· Enter at least higher than the output 2V, otherwise it can not be the regulator . Input voltage can not exceed 40V. The output current does not exceed 1A. Enter l2V words , the maximum output is about 10V .
Since reading LM317 internal linear regulator , so power consumption is relatively large. When the input voltage difference is relatively large and the output current is relatively large, do not pay attention to excessive power dissipation 317 . General increase power consumption does not exceed the heatsink 20W. Therefore recommends a pressure regulator large files .
◆ LM117/LM317 features:
· Adjustable output voltage : 1.25V to 37V continuously adjustable.
· Ensure 2.2A output current.
· Typical linear regulation: 0.01%.
· A typical load regulation : O.1%.
· Ripple Rejection : 80dB.
· Output short circuit protection.
· Overcurrent and overheating protection.
· Adjustment tube safe operating area protection.
· Standard three-terminal transistor package .
