5.8. Logic power output (5V)
The Tic’s 5V (out) pin provides access to the board’s 5V logic supply, which comes from either the USB 5V bus voltage or a 5V regulator powered by VIN, depending on which power source is connected. If power is supplied via VIN and USB at the same time, the Tic uses VIN.
The 5V regulator on the Tic T500 and Tic T825 is a low-dropout (LDO) linear regulator. The amount of heat generated by a linear regulator is proportional to the voltage drop from the output to the input multiplied by the output current (which equals the input current). The other main heat-generating component of the Tic is its stepper motor driver, which generates heat in proportion to the current it is supplying to the stepper motor coils. Therefore, to figure out how much current you can draw from the 5V pin without overheating the regulator, you have to consider two factors: the VIN voltage and the Tic’s configured motor current limit. The table below shows how much current you can draw from the Tic T825 5V pin at room temperature for various combinations of input voltage and stepper motor current, not including the current drawn by the Tic itself:
|VIN voltage||Motor current limit||Current available on Tic T825 5V pin|
|12 V||0.5 A||70 mA|
|12 V||1.0 A||70 mA|
|12 V||1.5 A||70 mA|
|24 V||0.5 A||70 mA|
|24 V||1.0 A||70 mA|
|24 V||1.5 A||50 mA|
|36 V||0.5 A||70 mA|
|36 V||1.0 A||50 mA|
|36 V||1.5 A||30 mA|
Note that the available current will be lower at higher ambient temperatures.
Note: While the Tic T500 can operate down to 4.5 V, power supply voltages under 5.5 V could cause a drop in the logic voltage of the board, potentially down to around 4 V when the power supply is 4.5 V. For more information about what effects this can have, see the note in Section 4.1.
The 5V regulator on the Tic T834 is an efficient switching step-up/step-down regulator. At least 450 mA is available on the Tic T834’s 5V pin when VIN is in the valid range.
The 5V regulator on the Tic T249 is an efficient switching step-down regulator. At least 400 mA is available on the Tic T249’s 5V pin when VIN is in the valid range.