10V to 1700V DC

Denny VV

Other Parts Discussed in Thread: PMP21735

Hi Team,

1) We need to convert input voltage "10VDC" to output "1700 V DC". We need to charge the Load 275uF Capacitor to 1700V within 10 sec.
Please suggest the efficient IC and the design.

2) In the reference design, https://www.ti.com/tool/PMP21735, the Transformer ratio is 1:6. Input: 32V and Output: 400V. I would like to know how 400V output is obtained. Because with 1:6 ratio, only 32*6=192V can be obtained.

Thanks,

Denny

over 3 years ago

0 Hong Huang over 3 years ago

TI__Guru 51175 points

Hi,

A flyback input and output has the below relationship, roughly:

Vout = (Vin/Nps) x D / (1-D)

Vout: output voltage

Vin: Input voltage

Nps, transformer turns ratio

D: duty cycle

So in PMP21735 case, Vin = 32V, Nps = 1:6, and if D = 0.68, then Vout = 408V

You can make similar design, but in general, max D is designed < 0.70 as a rule of thumb.

0 Denny VV over 3 years ago in reply to Hong Huang

Prodigy 175 points

Hi Team,

Please help me with one more question,

In section "2.2 Efficiency Data" in the user guide of PMP21735, it's mentioned that, with Input: 12V, Output of 381.3V, is obtained.

With 32V, the equation Vout = (Vin/Nps) x D / (1-D) gives 408V. But please help in understanding at 12V input. Because the transformer ratio is still 1:6.

Even if I consider 70% duty cycle then Vout = 12*6*0.7/(1-0.7) = 168V.

Thanks,

Denny

0 Hong Huang over 3 years ago in reply to Denny VV

TI__Guru 51175 points

Then Duty will be > 0.7. Note max D < 0.7 is just rule thumb. So D = 0.85 is needed for 12V input.

0 Denny VV over 3 years ago in reply to Hong Huang

Prodigy 175 points

Hi Hong,

Thank you very much.

Please let me know if there is any option to simulate the circuit for our application: 10V to 1700V.

Thanks,

Denny

0 Hong Huang over 3 years ago in reply to Denny VV

TI__Guru 51175 points

I do not have such a simulation option.

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10V to 1700V DC