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TIDA-010042: TIDA-010042 and TIDA-00120 Q1 Usefulness

Part Number: TIDA-010042
Other Parts Discussed in Thread: TIDA-00120

In both TIDA-010042 and TIDA-00120, Q1 is oriented with the body diode conducting in the direction of current flow. It seems then that Q1 is wholly ineffective as a switch, and merely decreases the series voltage drop with the solar panel when toggled. Can you confirm that this is the case?

Additionally, if Q1 was oriented in the opposite direction and thus actually able to block current flow, it would seem to truly float the panel from system ground, making meaningful voltage measurements impossible.

Am I missing something?

  • Hello, 

    1. The function of this switch (Q1 for TIDA-00120 or Q4 for TIDA-010042) is reverse panel protection and to avoid battery discharging into panel. There is no need to remove the panel from the circuit in any operating condition. 

    2. If you look at the design guide of TIDA-010042 2.4.5 Panel Voltage Measurement. You will find that the voltage sense of floating panel is able to measure with the PNP circuit. 

    Hope it helps and let me know if you have any further question.