TPS61085: 5V to 52V boost circuit

Kazuto Tatsumi

Part Number: TPS61085
Other Parts Discussed in Thread: LM25180, TPS61087, TPS61175, LM5157,

Hi team,

My customer wants to generate +52V/20mA for phantom power and +/-13V/30mA for OPAMP from 5V, for mixer application. Currently they consider to use the circuit as below with external charge pumps, but if you have another recommended IC or topology to generate the output, could you let me know?

Regards,
Kazuto

over 2 years ago

+1 Yichen Xu over 2 years ago

TI__Expert 4760 points

Hi Kazuto,

For multi output, flyback is also considerable. You may need 3 output windings.

https://www.ti.com/lit/an/slva496/slva496.pdf?ts=1631524947234&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTPS61085%253FkeyMatch%253DTPS61085%2526tisearch%253Dsearch-everything%2526usecase%253DGPN

0 Kazuto Tatsumi over 2 years ago in reply to Yichen Xu

TI__Intellectual 2820 points

Hi Yichen,

Thanks for your suggestion. What is the concern of external charge pump for audio application? Is flyback recommended in this case?

Regards,
Kazuto

+1 Yichen Xu over 2 years ago in reply to Kazuto Tatsumi

TI__Expert 4760 points

Hi Kazuto,

The main concern is that there is forward voltage of diode, which will decrease the output voltage for the 4*Vs setting. Flyback brings better voltage accuracy if the transformer is well designed.

0 Kazuto Tatsumi over 2 years ago in reply to Yichen Xu

TI__Intellectual 2820 points

Hi Yichen,

Do you have any idea for another IC suitable to control the 3 output Flyback? (5V to +52V, +/-13V)

I have found LM25180 but I'm not sure it's suitable or not.

Regards,
Kazuto

0 Yichen Xu over 2 years ago in reply to Kazuto Tatsumi

TI__Expert 4760 points

Hi Kazuto,

TPS61087, TPS61175 is ok for your application. I double checked the load, TPS61085 doesn't have enough current limit. If you want to use controller, LM5157 is ok.

0 Kazuto Tatsumi over 2 years ago in reply to Yichen Xu

TI__Intellectual 2820 points

Hi Yichen,

Thanks for checking about the current limit. Could you explain more specifically? When is the current limit exceeded? (e.g. every switching cycle, inrush current at startup, etc.).

If it happens only at the startup inrush, then do you have any idea to reduce that?

This is because the customer wants to use TPS61085 in terms of the cost. In case it is seriously not recommended, I'll try to persuade the customer.

Regards,
Kazuto

+1 Yichen Xu over 2 years ago in reply to Kazuto Tatsumi

TI__Expert 4760 points

Hi Kazuto,

My bad, it should be ok. To reduce inrush current, increasing the SS capacitance is enough.

0 Kazuto Tatsumi over 2 years ago in reply to Yichen Xu

TI__Intellectual 2820 points

Hi Yichen,

Thanks for your support! The customer is still interested in TPS61085, so I'll suggest it at first.

Regards,
Kazuto

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TPS61085: 5V to 52V boost circuit