MAX25510/11 GA GB PWM FLTB output & boost current limit

Hello,

1. This will depend upon your application's specifications. The current limit refers to the inductor current that is limited/monitored for proper circuit operation. A higher current limit is used for increased output power. If the load draws current greater than 3A and below 4.5A, MAX25511 is more suitable. Otherwise, if it doesn't draw greater than 3A, MAX25510 should be fine.

2. The MAX25510ATGA/V+ also has the FLTB function. The difference between the two is that the FLTB pin for MAX25510ATGB/V+ has a PWM output while the MAX25510ATGA/V+ has a latched output.

Regards,

Nino

Hello,

1. This will depend upon your application's specifications. The current limit refers to the inductor current that is limited/monitored for proper circuit operation. A higher current limit is used for increased output power. If the load draws current greater than 3A and below 4.5A, MAX25511 is more suitable. Otherwise, if it doesn't draw greater than 3A, MAX25510 should be fine.

2. The MAX25510ATGA/V+ also has the FLTB function. The difference between the two is that the FLTB pin for MAX25510ATGB/V+ has a PWM output while the MAX25510ATGA/V+ has a latched output.

Regards,

Nino

Hi Nino,

Thanks for your reply.
1. I'm still confuse about the boost current limit. In MAX25510/11, the max current per string is 120mA. There are four channel, so the max total load is 120mA*4channel= 480mA. What's  the boost current limit for?
2. "MAX25510ATGB/V+ has a PWM output"=>Does the differnet frequency or duty of PWM represent differnet fault status?

As this is a boost converter the boost current limit together with the input voltage set the input power which of course must be greater than the desired output power. The output power is the boost output voltage times the output current.

Let's assume the output voltage is 30V at 480mA - that equates to 14.4W output power. If the converter needs to work down to 5V that corresponds to an average input current of 14.4/5=2.88A. Considering the efficiency of the converter (inevitably less than 100%) and the input ripple current the MAX25510 might not be suitable for this particular application as it has a 3A current limit, as you pointed out.

In general the input current needs to be calculated using the output power and efficiency and also take account of the ripple. We do not want the input current to reach the current limit as that will mean a limit in output power.

Regarding your second question: yes, the FLTB output is in PWM format and the duty-cycle indicates the type of fault.

Hi Phim,

Thanks for your reply.

Regards,

Nina.