Part Number: LM96163
Other Parts Discussed in Thread: AMC6821,
Tool/software:
Hi expert,
May I have your help to explain more detail what's the meaning of bit0 & bit1 of reg4A?
Customer find when reg03=0x4, and Smart Tach mode is enable, they would heard some fast/slow audible noise at low speed but wouldn't happen if bit0 & bit1 of reg4A set to [0,0]
Regards,
Allan
TACH= 01,10, and 11 state they are for "Use with direct PWM drive of fan power." This refers to "3 pin fan" where the power and PWM are the same. A "4 pin fan" has a separate PWM input, and should not be used with Smart Tach mode. Smart Tach is meant to resolve an issue with 3 pin fans by keeping their power on during measurement.
This artwork from AMC6821 datasheet shows circuit for 3 pin fan that has a discrete FET for low side drive of the fan power.
LM96163 typical application shows a 4 pin fan. The 4 pin fan has integrated PWM driver.
thanks,
ren
