TPS25942 Slave fault in Priority power multiplexing mode

matt spencer

Other Parts Discussed in Thread: TPS25942A

We designed a circuit based on fig 79 of the datasheet. Operationally everything seems to be working fine, but we are monitoring the FLTn lines.

FLTn on the slave device is low If Vuv<Vin1<Vov (set to 5V +/- .5) and Vin2 is 5V

Is there a way to operate in this mode without causing a fault condition on the slave device?

over 9 years ago

0 Dinesh Kumar6 over 9 years ago

TI__Intellectual 2980 points

Hello Matt,
will study your proposal and get back to you.
Is there any specific reason for using the PGTH instead of OVP.
OVP is well tested and proven.

Regards
Dinesh

0 matt spencer over 9 years ago in reply to Dinesh Kumar6

Prodigy 30 points

PGOOD(PGOOD1) from the top ic is connected to OVP. Sorry, that's a named connection.
PGTH is pulled high to the output.

0 Dinesh Kumar6 over 9 years ago in reply to matt spencer

TI__Intellectual 2980 points

Hello Matt,

In that case our proven configuration shown in data sheet will work/.. right?

Please let me know if you need further support on this.

Regards

Dinesh

0 matt spencer over 9 years ago in reply to Dinesh Kumar6

Prodigy 30 points

It "works". I'm just trying to understand why a fault is produced in the IC not being used.

Matt

0 Dinesh Kumar6 over 9 years ago in reply to matt spencer

TI__Intellectual 2980 points

Matt,
The fault signal drive the second IC so that is does come only when first IC does not have power good condition.
when input power to the first IC is in good condition you do not want second IC to feed power to the output.
Please refer to 11.3.1.2 Priority Power MUX Operation and Figure 79 (Priority Power Multiplexing Implementation) in the TPS25942A data sheet for more details.

Regards
Dinesh

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TPS25942 Slave fault in Priority power multiplexing mode