Patent ID: 8653849

Claim:
A voltage margin testing device for testing voltage margin of a unit under test including a voltage terminal, the voltage margin testing device comprising: a button module that selectively allows adjustment of a constant voltage value of a voltage of the voltage terminal, the button module comprising a first button and a second button, each of the first button and the second button grounded through a current limiting resistor; a microcontroller electronically connected to the button module; and a digital potentiometer electronically connected to the microcontroller and the unit under test; wherein selection of the button module causes the microcontroller to adjust a resistance of the digital potentiometer causing the voltage of the voltage terminal to change in increments of the constant voltage value according to the resistance of the digital potentiometer; each time the first button is pressed, the voltage of the voltage terminal increases the constant voltage value, each time the second button is pressed, the voltage of the voltage terminal decreases the constant voltage value; and wherein when the voltage of the voltage terminal is not within the voltage margin, the unit under test works abnormally and sends an error signal to the microcontroller, the microcontroller receives the error signal and adjusts the resistance of the digital potentiometer to change the voltage of the voltage terminal in increments of the constant voltage value until the unit under test works normally, after the microcontroller receives the error signal and adjusts the resistance of the digital potentiometer causing a variation of the constant voltage value in the voltage of the voltage terminal, the unit under test restarts under the control of the microcontroller; when the first button is pressed, and the unit under test works normally after the restart, the voltage of the voltage terminal is an allowable maximum voltage value of the unit under test.