TPS1663: question regarding TPS1663

Hello Masa-San,

Please find replies below:

1. what kind of behavior will TPS1663 will do in case of current limit?

-> shutdown ? or will IC try to clamp the amount of current customer set ?

TPS16630 will limit the current for duration of t_{CL_PLIM(dly)} [~162ms] input before shutting down. If the device junction temperature reach Thermal shutdown temperature before this time (162ms), the device shuts down. Please see Section Section 9.3.4 in datasheet. Device will auto-retry or latch-off based on MODE pin configuration.

2. Can customer set up the current limit as 7A since it might have 6A as transient current when system powers on.

TPS16630 can support a transient current of 2xIOL (12A max) for a duration of ~3us. If the duration of transient is higher, the device will turn-off the internal FET. It can support continuous output current of 6A.

3. will its RΘja be changed if time passed during current limit?

-> i know there are other factor which influence on how much RΘja is like solder joint area and so on.

can we say that RΘja will be changed if time passes (1second later, 30second later.)

or, the RΘja would be same constant ?

R_θJA is typically used for steady state thermal conditions. See Section 1 in Appnote : Semiconductor and IC Package Thermal Metrics

For transient thermal behavior, please see Figure 13 on Page 10 of the datasheet.

hi, Lokesh-san.

please see below my reply on each of your answer as in line.

Lokesh Ghulyani said:

Hello Masa-San,

Please find replies below:

1. what kind of behavior will TPS1663 will do in case of current limit?

-> shutdown ? or will IC try to clamp the amount of current customer set ?

TPS16630 will limit the current for duration of t_{CL_PLIM(dly)} [~162ms] input before shutting down. If the device junction temperature reach Thermal shutdown temperature before this time (162ms), the device shuts down. Please see Section Section 9.3.4 in datasheet. Device will auto-retry or latch-off based on MODE pin configuration.

[MASA]does it mean that the current will be constant during current limit.

(ex: current limit is 5A, once the current hits 5A, and it would be constant in 162ms , it would be auto retry and latch off. right?)

so can customer choose either current at output would be constant or latched off, correct ? 

2. Can customer set up the current limit as 7A since it might have 6A as transient current when system powers on.

TPS16630 can support a transient current of 2xIOL (12A max) for a duration of ~3us. If the duration of transient is higher, the device will turn-off the internal FET. It can support continuous output current of 6A.

[MASA]Where can i get above information from datasheet?

3. will its RΘja be changed if time passed during current limit?

-> i know there are other factor which influence on how much RΘja is like solder joint area and so on.

can we say that RΘja will be changed if time passes (1second later, 30second later.)

or, the RΘja would be same constant ?

R_θJA is typically used for steady state thermal conditions. See Section 1 in Appnote : Semiconductor and IC Package Thermal Metrics

For transient thermal behavior, please see Figure 13 on Page 10 of the datasheet.

[MASA] thermal resistance would be constant but thermal IC dissipates would be varied , correct ?