Other Parts Discussed in Thread: TPS1653
Hello,
as a substitute part for our old product with LTC4217 I've chosen LM5069. The new requirement was higher voltage range (18V - 30V)
Requirements: UVLO, adjustable overcurrent limit, adjustable overcurrent delay, adjustable dVdT
I designed a new board based on LM5069 set to Ilim(ty) = 0.65A and 1ms fail delay.
I prepared small test where I applied pulse load 1A/800us on the output of LTC4217(old solution) or LM5069 and compared both solution.
The main distinction is that LM5069 still can pass much higher currents to the load without active current limiting, but LTC4217 quickly regulates the output current (Ilim).
To my amazement, I was really badly surprised that I hadn't understood the functionality of LM5069... maybe I set the current limit to 0.65A by 80mΩ resistor but there is nothing like active current limiting up to Ilim x 1.9.
This feature is not possible in my design and I need to choose another hotswap/efuse which will act immediately like active current limiter (Iout>Ilim).
LM5069
Current Limit(typ) = 0.65A
Current Breaker(typ) = 1.9 x 0.65A = 1.235A
tfault = ~1ms
As you can see in the picture below, there is 1.28A pulse for approximately 800us and LM5069 do nothing with this current despite the setting of current limit 0.65A -> I’ve found out that LM5069 can’t actively regulate current which is smaller than Current Breaker (1.9x current limit)…
LTC4217 AD
Current Limit(typ) = 1A
tfault = ~2ms
As you can see in the picture below, there is small peak current but after several microseconds an internal regulator will reduce current to the load based on Current Limit setting (1A). And this is desired feature, no more current to the load.
Please I need to find TI part that follows my requirements (LTC4217) with enhanced voltage range 18V-30V.
Thanks to everyone.
Tomas
