ULQ2003A-Q1 9 pin COM connect air,Is it acceptable?What's the impact?
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Hi User,
Thanks for reaching out on E2E! The COM pin is important when using low side switches, such as the ULQ2003A-Q1, to power inductive loads. When the low side switch is disconnected from GND, the current through the inductive load is instantly disconnected, causing the voltage to spike (V = -L * dI/dt)
Connecting the COM pin enables the flyback diode whenever this switching condition occurs. Once the voltage starts increasing, the diode becomes forward biased and gives the current a path to flow.
Thanks,
Arthur Huang