LTC4162 Step-down functionality

Thread Starter

trebla

Joined Jun 29, 2019
209
Hi folks, can someone have knowledge of possibilities getting from LTC4162 Vout (or PowerPath in Linear terms) stepped down voltage, for example if Vin = 24V then Vout = 12V?
 

Papabravo

Joined Feb 24, 2006
14,461
This is a fairly complicated part. It is designed to be used with a battery. Is that what you have in mind?
If you do not have plans to use this with a battery, then I suggest you look for an alternate part. The LT1776 is a fine Buck Converter that will meet your needs, so far as I understand them.
 

Thread Starter

trebla

Joined Jun 29, 2019
209
I need battery management too, there is requirement for using 12V 9Ah SLA battery and battery state telemetry. The problem is that system power need to be 12V. If the LTC162 does not step down the input voltage for system path then i am forced to use some buck converter or even buck-boost one. But unfortunately the PCB must fit to quite small area. Needed output current is about 3A + 0.8A battery charging.
 

Papabravo

Joined Feb 24, 2006
14,461
I need battery management too, there is requirement for using 12V 9Ah SLA battery and battery state telemetry. The problem is that system power need to be 12V. If the LTC162 does not step down the input voltage for system path then i am forced to use some buck converter or even buck-boost one. But unfortunately the PCB must fit to quite small area. Needed output current is about 3A + 0.8A battery charging.
Do you see anything in the datasheet that says it will not step down the input voltage to suit the particular battery of your choice. You know your requirements better than I do - why are you asking me?
 

Thread Starter

trebla

Joined Jun 29, 2019
209
I can see it steps down for battery but datasheet tells nothing about stepping down for system path. Maybe there is no such functionality, i asked because i was'nt sure. And lack of system path step-down functionality complicates my life, which is bad :(
 

Papabravo

Joined Feb 24, 2006
14,461
I'm not clear on the overall plan. Are you saying that you want BOTH battery management AND a separate converter that has nothing to do with the battery, and for some reason you can't separate these two functions into separate parts.
 

Thread Starter

trebla

Joined Jun 29, 2019
209
I need 12VDC to system power path with battery backup and management. If exist possibility to get from LTC4162-s Vout 12VDC at Vin 24VDC, then i can go without separate converter.
 

Papabravo

Joined Feb 24, 2006
14,461
I need 12VDC to system power path with battery backup and management. If exist possibility to get from LTC4162-s Vout 12VDC at Vin 24VDC, then i can go without separate converter.
As I see your problem, you want the output to be +12 VDC, even if that +12 VDC is not sufficient to charge the battery. Is that correct? If you require 13.8 VDC to charge a 12V SLA battery then no this part will not work for you.
 

Papabravo

Joined Feb 24, 2006
14,461
I did not look closely at the I2C interface to see if there is some provision for charging the battery when Vout is not required, or can be higher than it would otherwise be. This is a complex chip and may have some magic under the hood.
 

Thread Starter

trebla

Joined Jun 29, 2019
209
I think i will still use this LTC4162 as input for PSU and for battery management. For 12VDC output i have found LTM4607, LTM4609, LTM8054, LTM8056 so far and currently reading their datasheets. Strange thing, i found nothing from TI with search terms Vin min = 11V, Vmax = 30V, Vout min = 12V and Iout min 3A for buck-boost converters.
 
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