I would like to ask some information regarding the AAM resistor value. Performed the measurement for different load (100,300,500)and calculated efficiency for 3 different values of AAM resistor.
Specification in test measurement:
Vin: 13.5V, Vout:3,3V, L-2,2uH.
3.37.4K ( this value is calculated as per the specification input - Figure 7, AAM value -0.225)
- 68K efficiency is high and switching frequency not within the specification for light load current.
Ex:efficiency =86%, fs = 1.0936 load current = 100mA, Vin=13,5V
2.40,2K, efficiency is reduced and switching frequency is within the specification for light load current
Ex.efficieny = 73%,fs = 1.998, load current = 100mA, Vin=13,5V
3.37.4K,efficieny is reduced further and switching frequency is within the specification for light load current
Ex. efficiency= 69%, fs=1.953, load current =100mA, Vin=13,5V
- Which resistor value is recommended to choose from the above results?
- which factors is important in terms of choosing the resistor value is it switching frequency or efficiency for light loads?
- when the resistor value is calculated as per the specification, efficiency is low? why? based on how the value needs to be calculated.