HERE, there are several questions when i use ADN8830 as the TEC controller.
1. In the high temperature test(60℃), when the pin 15(VLIM) was connected to the GND, the current of the TEC controller was smoothly increased which is like the linear curve. BUT THEN, the current was the sharply increased from 700mA to 1.7A in 30 second. if a voltage applied to the VLIM input to the ADN8830, the sharply increasing will not happen again. WHY?
(The max of TEC current is 1.9A,The max of TEC voltage is 6V, we use FDW2521 as the MOSFET)
2. we use the multimeter to measure the current and voltage of Q3(P-MOSFET) in the AN8830 datasheet Fig.1, Page7.
Notice that the voltage of Udg is reversed to the positive number at the beginning of cooling period.
i just wanna know that these two phenomenons are OK or WRONG 'caused by some reasons????