TPS65400: TPS65400 Power Good and EN pin function

Hi Dilip

1. Firstly, if ENABLE_PIN_CONFIG selects active ENABLE, as is described in section 8.6.2.3 of the datasheet of TPS65400, when EN pins are kept floating, the device can turn on if VIN is applied. But if ENABLE_PIN_CONFIG selects inactive ENABLE, the state of EN pins is ignored.

2. PGOOG_PIN_CONFIG sets the function of the global PGOOD pin, as is described in section 8.6.2.3 of the datasheet. By default, the global PGOOD is configured to output a logical AND of each individual power supply's PGOOD, which means that if out of 4 channels Ch1 and Ch2 EN is grounded (active ENABLE) and VIN is applied to all four channels, global PG is low. You can also refer to Table 21 and 22, the global PG can be set a logical OR of each individual power supply's PGOOG. Actually, PG is used to reflect the state of VOUT, so the level of VIN, PVIN, EN, CE and SS can all affect VOUT and further affect global PG.

If you have any question, please let me know. And you can email me directly.

Hi ,

If we are using only the channel 1 &2 and the 3&4 we are not using and not connected the PVIN to those 3&4 and the Enable pins are grounded for those . Does the global power good will generate only for the 1&2?

Lijeesh

Hi

You can write 00011 to PGOOG_PIN_CONFIG so that the global PGOOD outputs AND logic of only channel 1 & 2 in the section highlighted of the picture below. If you want the global PGOOD outputs OR logic of only channel 1 & 2, please write 10011 to PGOOG_PIN_CONFIG. The control logic can be found in Table 21 in the datasheet of TPS65400. 

Hi,

If I am connecting the Enable pin and FB pin of unused channel's to active channel's Enable and FB pins respectively, shall the Global power can be generated ? 

Lijeesh