LM337 Adjustable output negative voltage regulator

Here we have to learn or introduce about  IC LM337, it is an adjustable 3 terminal negative voltage regular capable of supplying in excess of 1.5A over an output voltage of -1.2V to -37V. The LM337  serves a wide variety of applications including local, on-card regulations. The LM337 is the equivalent counterpart of the LM317 positive voltage regular. The IC comes in three terminals standard TO-220 package. Getting the output voltage with this regulator is very easy and required only two external resistors to set the output voltage. So it can be used for a wide variety of applications in programmable voltage regulator and precision current regulator.  The IC commonly used in adjustable lab voltage in combination with the LM317 IC. The device features with internal current limiting, thermal shutdown, and safe area compensation. Here the post is given below that the IC LM337 must be used for reference from the LM337 datasheet.

LM337 Voltage Regulator Descriptions:

The LM337 is the basically equivalent counterpart of the LM317 positive voltage regulator.  This IC is commonly used in adjustable lab voltage generators in combination with the LM317 IC. It can be also used in the current regulator. This IC is basically three PINs in which the input voltage supplied to Vin pin then using a pair of the register that we set a voltage at adjusting pin which will decide the output voltage of the IC that given out at Vout pin. The below circuit is shown for reference from the LM337 datasheet.

LM337 voltage regulator description

The output voltage thus obtained can be calculated using the below formula.

Vout  = - 1.25 × [1 + (R2/R1)]

The actual formula in the datasheet will also include current through the adjust a pin but for a simplification purpose, we have assumed Iadj to be 50uA constant which will slightly differ in the practical application. Also, note that the output current of the IC will not be 1.5A always if the difference voltage between the input and output voltage is high the output current will also decrease. 

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