LT1054: Charge pump for Negative voltage

Pedaiah G

Prodigy 230 points

Part Number: LT1054

Hi,

I am using LT1054 in my design for Negative voltage generation for 3 different circuits.

The designed circuit is shown below.

Request your comments on design and any others circuit elements to be added for proper output and filtering.

Thanks and Regards,

Pedaiah G.

over 2 years ago

+1 Brigitte over 2 years ago

TI__Guru 58225 points

Hello Pedaiah,

We recommend a CIN / COUT ratio of 1 / 10, so increasing the input capacitor to 10uF is recommended.

Other than this, the schematics seem to be ok.

Best regards,
Brigitte

0 Pedaiah G over 2 years ago in reply to Brigitte

Prodigy 230 points

Hello Brigitte,

Thank you for quick response.

Noted.

Regards,

Pedaiah G.

0 Pedaiah G over 2 years ago in reply to Brigitte

Prodigy 230 points

Hello Brigitte,

As per datasheet, We have considered CIN as 10uF between CAP+ and CAP-, COUT as100uF between VOUT and GND pins.

Can you clarify on the input capacitor you recommended?

Thanks and Regards,

Pedaiah G.

0 Brigitte over 2 years ago in reply to Pedaiah G

TI__Guru 58225 points

Hello Pedaiah,

VCC is delivering the energy to the flying capacitor (one on CAP+ to CAP-) as well as the energy to charge VOUT. If you only have a 1uF cap on VCC, but a 100uF cap on VOUT, at startup the VCC capacitor will have issues to keep the input voltage stable.

Best regards,
Brigitte

0 Pedaiah G over 2 years ago in reply to Brigitte

Prodigy 230 points

Hello Brigitte,

OK Noted. Thank you for the clarification.

Regards,

Pedaiah G.

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LT1054: Charge pump for Negative voltage