DC-DC Converter Design

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sinanics

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Hi,

One of my friend is working on a level measurement project using ultrasonic sensor. And he sent me a requirement as below to help him with the transformer design. Any ideas how to go about it and what further details are required further?

Requirement : High frequency Transformer
Switching Frequency : 40 – 43 KHz
Transformer Primary : 5V from a controller at 40 -43 KHz
Transformer Secondary : 90 – 150V at 40 – 43 KHz
Primary current : 0.5 A
Secondary current : max of 0.75-1A

The micro controller will generate a 40KHz frequency. But the sensor will work only with 90 or above voltage. So I can’t couple the sensor directly with the controller. So I am looking for a step up transformer at high frequency of operation.


Thanks .
 
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something wrong with your requirements.
Going by secondary current to 1A, @ say lowest secondary voltage 90V... 90Watts ? ok, maybe 50% duty cycle but still 45W minimum?
and your saying the primary 0.5A @ 5V.

you need to review/check your requirements.
This sort of power is needed for ultra-sonic cleaners, I have doubt you need that for a measurement purpose ?
 
So you are meaning that the required secondary power cannot be delivered by primary? May be if primary was 5V @ 10A, should have been right (assuming at 50% duty cycle as mentioned by you)? Anyway, I shall check up on this as I do not have ready info.
 

The current-turn products for both the primary and secondary should be equal. And 45W is a huge amount of power for ultrasound. Are you sure you're not off by a factor of ten?
 

Hi,

The updated requirement is as follows

Switching Frequency : 40 – 43 KHz
Transformer Primary : 24V from a controller
Transformer Secondary : 90 – 120V
Primary current : 1.5-2A
Secondary current : max of 0.75-1A

Would this be a realizable design? If yes, any further info is required?
 

As was mentioned before, the power requirements for the secondary exceed the input power.
Empirically need to deliver maximum 120V/1A= 120 watts
On the 24V need to have available at least 5 Amps.
 

mister_rf said:
As was mentioned before, the power requirements for the secondary exceed the input power.
Empirically need to deliver maximum 120V/1A= 120 watts
On the 24V need to have available at least 5 Amps.
Click to expand...

Sorry, I made a typing error. The secondary ct. is 0.5A. For primary let us assume at the moment the ct. is 5A (for want of progress in the design).
 

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