TPS25942A: Space-grade DC-DC (600 nV) Power Supply...

user6106687

Part Number: TPS25942A
Other Parts Discussed in Thread: TPS25940

Sir/Madam,

I am fabricating two space-grade power supplies: one of which utilises the Analog Devices LTC 4425 to both charge and regulate two 400 F super capacitors; one of which utilises the Texas Instruments TPS 25942 to both charge and regulate a single 7.5 F super capacitor. I was unable to identify a suitable circuit schematic, in respect of the Texas Instruments eFuse component! Do please advise...

Do please advise.

Scott -- UK.

over 6 years ago

0 Rakesh over 6 years ago

TI__Guru** 105721 points

Hi Scott,

Welcome to E2E!

What is the input voltage and super capacitor rating ?

Please check whether this app note helps http://www.ti.com/lit/an/slva920/slva920.pdf and let me know if you have any questions.

Best Regards,

Rakesh

0 user6106687 over 6 years ago

Prodigy 40 points

Hello there, Rakesh,

The input voltage from the regulator is: [5.000 V];

The AVX (7.5 F) super capacitor rating is: [5.0 V].

Scott -- UK.

0 Rakesh over 6 years ago in reply to user6106687

TI__Guru** 105721 points

Hi Scott,

It is possible by sizing capacitor on dVdT pin for TPS2594x device as covered in that app note. You may need ~100uF for CdVdT. Please check and let me know if you see any issues for your system functionality.

Best Regards,

Rakesh

0 user6106687 over 6 years ago in reply to Rakesh

Prodigy 40 points

Hello there, Rakesh,

Are you referring to your own document: 'Charging Super Capacitor With eFuse' - figure 5a - page 5? There is a circuit schematic comprising of five parts:-

* TPS 25940 --> Replace with TPS 25942;

* Resistor X;

* Super Capacitor Y;

* Capacitor A;

* Capacitor B.

Scott -- UK.

0 Rakesh over 6 years ago in reply to user6106687

TI__Guru** 105721 points

yes Scott. Fig 5a.

You can use either TPS25942 or TPS25940. It does not make any difference for this function.

0 user6106687 over 6 years ago in reply to Rakesh

Prodigy 40 points

Hello there, Rakesh,

Since I wish to fabricate a single super capacitor Ultra Low Noise Estimated Serial Resistance board using the following components:-

[Input from LT-3045 (x6) regulator: 5.000 VDC|3.00 A; Output from super capacitor: 5.000 VDC]

1. Power Management Controller (eFuse): Texas Instruments TPS 25942;

2. Output Super Capacitor: AVX SCM Series 7.5 F|5.0 V|ESR: ~55 mOhms;

3. Current Limit Resistor (RLim): Vishay metal foil (0.02 % tolerance) --> X;

4. Capacitor (dVdT): Panasonic Organic Aluminium Polymer (ESR: ~10 mOhms) --> Y;

5. Capacitor (CIn): Panasonic Organic Aluminium Polymer. (ESR: ~10 mOhms) -- > Z..

What should the values for X, Y and Z be?

Scott -- UK.

0 Rakesh over 6 years ago in reply to user6106687

TI__Guru** 105721 points

Hi Scott,

Please use as below.

RLim resistor X= 47kOhm

dVdT capacitor Y= 100uF

CIn capacitor Z=0.1uF

Best Regards,

Rakesh

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TPS25942A: Space-grade DC-DC (600 nV) Power Supply...