TPS92518HV: TPS92518HV reduce idle power consumption

Hendrik P

Part Number: TPS92518HV
Other Parts Discussed in Thread: TPS92518EVM-878, LEDSPIMCUEVM-879, TPS92518

Hi,

I am planning to reduce the idle-consumption of a device. Right now, the VIN pin of the TPS92518HV draws 3-4mA when idling, which is to much for my application.

Is it safe to switch of the power-supply at VIN (e.g. PMOS to supply-voltage) to reduce the power consumption of the chip - when CSP1 and CSP2 still "see" the supply voltage?

Best regards,

over 5 years ago

0 Irwin Nederbragt over 5 years ago

TI__Mastermind 28655 points

Hello Hendrik,

I recent was asked this question elsewhere and found out it is okay to do this.

Best Regards,

0 Hendrik P over 5 years ago in reply to Irwin Nederbragt

Prodigy 110 points

HI Irwin,

I did some tests with the EVM board and finally remove R16 to keep VIN floating.

When powering up the board - MCU control board connected (only connected to PC, not having the SW running), 48V at CSP1/2 and R16 open (VIn floating) the TSP just blew up in smoke...

I am not sure if it was some bad soldering, I have to wait for replacement parts, or its an general issue.

Do you have an TPS92518EVM-878 to verify this?

0 Irwin Nederbragt over 5 years ago in reply to Hendrik P

TI__Mastermind 28655 points

Hello,

I am re-asking this question to verify this is true.

Are you doing anything with Vdigi?

Best Regards,

0 Hendrik P over 5 years ago in reply to Irwin Nederbragt

Prodigy 110 points

Hi Irwin,

I am not sure what you mean with Vdigi.

I only plugged in the MCU control board (LEDSPIMCUEVM-879) and did not start the software on the PC.

The TPS92518EVM-878 was connected to the MCUEVM -

So i think nothing was going on on the SPI line.

0 Irwin Nederbragt over 5 years ago in reply to Hendrik P

TI__Mastermind 28655 points

Hello,

There is a path on the schematic that applies voltage to Vcc on the enable (Vdigi on the connection J10) to the TPS92518.

Best Regards,

0 Hendrik P over 5 years ago in reply to Irwin Nederbragt

Prodigy 110 points

Hi Irwin,

When attaching USB to the MCU board VDIGI is 3.3V. But VDIGI is only used as pullups for the MISO/MOSI lines?! MISO/MOSI have been pulled up to 3.3V then.

The MCU board - when powered up - also enabled the Enable pin, so TP_1 ENABLE is at 3.3V.

I just measured the output voltages of the MCU. The resulting signals for the TPS92518HV had EN/UV PIN on High, VIN floating, but CSN1/2 at 48Volts, PWM1/2 at 3.3V. MISO/MOSI pulled up to 3.3V.

Can this happen cause the EN is high - but VIN is low/floating?

0 Irwin Nederbragt over 5 years ago in reply to Hendrik P

TI__Mastermind 28655 points

Hello,

I haven't heard back from the others I asked about this. If you look at Vdigi it connects to D5 which goes to EN, there is a zero ohm resistor, R5, that also goes to VCC1. The idea of removing Vin from the input voltage is to prevent the logic from being powered. It seems there may be paths for external voltages to get to the logic on this board even though it is not 5V. I will be asking again today. One of the engineers was off yesterday.

Best Regards,

0 Hendrik P over 5 years ago in reply to Irwin Nederbragt

Prodigy 110 points

Hi Irwin,

VDIGI is not connected to D5 in my sluubm0c.pdf - TP1-Enable is not shorted with VDIGI.

But TP1 Enable is 3.3V Volts, cause the MCU board gives 3.3V if the software is not started. So the TPS Enable pin is 2.3V (after D5) -> logic high. Does this mean if we don't have any voltage on VIN _but_ enable is High the TPS will be destroyed?

R5 and R1 are not placed on the EVM board.

0 Irwin Nederbragt over 5 years ago in reply to Hendrik P

TI__Mastermind 28655 points

Hello,

I received some feedback but no answers yet. I will ask again.

Best Regards,

0 Irwin Nederbragt over 5 years ago in reply to Irwin Nederbragt

TI__Mastermind 28655 points

Hello,

Sorry this is taking so long, I still haven't heard from one person.

Best Regards,

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TPS92518HV: TPS92518HV reduce idle power consumption