Dear guys,

I am using a transducer Vac to Idc(4-20mA) and AC supply is used to operate module, In this module an IC(TOP242-250) is used after Bridge Rectifier .
I have download its data sheet but can't understand properly, Kindly guide me what is the function of this IC in this module.
https://eu.mouser.com/datasheet/2/328/top242-250-9213.pdf

 

hi MZ,
Welcome to AAC.
The IC is a Switched Mode Power Supply. [SMPS]
Please post a circuit diagram of your project.
E

 

It is the control and switching element of the switch mode power supply. It converts the high voltage DC from the output of the bridge rectifier to the low voltage DC for the electronics. A SIMPLIFIED description is that it converts the DC to high frequency AC (About 132 Khz according to the data sheet.) This is to allow the use of a much smaller transformer than would be required for mains frequency. With the aid of the feedback from the secondary side of the transformer via the optoisolator it controls the duty cycle of the AC waveform. (Which is pulses rather than a sine wave.) to regulate the output voltage. For more detailed information Google "Switch mode power supplies."

Les.

 

hi MZ,
Welcome to AAC.
The IC is a Switched Mode Power Supply. [SMPS]
Please post a circuit diagram of your project.
E

Thank You very much for your reply.

I have to read the AC voltage using PLC via Voltage Transducer (which converts 0~220Vac into 4-20mA) to display onto HMI. I am using Transducer(JIANGSU SERE ELECTRIC JD194-BS4U) (in which that IC is used) but transducer operating supply is 220VAC Supply. My Manager has asked that how can we (or) what we have to change to replace that AC power supply to DC 24V.

 

It is the control and switching element of the switch mode power supply. It converts the high voltage DC from the output of the bridge rectifier to the low voltage DC for the electronics. A SIMPLIFIED description is that it converts the DC to high frequency AC (About 132 Khz according to the data sheet.) This is to allow the use of a much smaller transformer than would be required for mains frequency. With the aid of the feedback from the secondary side of the transformer via the optoisolator it controls the duty cycle of the AC waveform. (Which is pulses rather than a sine wave.) to regulate the output voltage. For more detailed information Google "Switch mode power supplies."

Les.

Thank You very much for your reply and great explanation.

 

hi MZ,
I would use an off the shelf 220Vac to 24Vdc module rated a say 1Amp.
These modules are low cost and readily available.
E

 

Hi Eric,
I think you mean 24 V DC to 220 V AC.

Les.

 

Hi Les,
Perhaps I am misinterpreting the TS's text he says.
but transducer operating supply is 220VAC Supply. My Manager has asked that how can we (or) what we have to change to replace that AC power supply to DC 24V.

hi MZ,
Please clarify the requirement.


Eric

 

Hi Les,
Perhaps I am misinterpreting the TS's text he says.
but transducer operating supply is 220VAC Supply. My Manager has asked that how can we (or) what we have to change to replace that AC power supply to DC 24V.

hi MZ,
Please clarify the requirement.


Eric

Dear ericgibbs,

Sorry I cannot clarify my point. But I try to explain in detail:
*) I have to read AC 0~220Vac from my PLC.
*) For that I have used a Transducer which converts (0~220Vac) to (4~20mA) and transducer can be power up using AC,DC80~270V.
*) But unfortunately, I have only 24Vdc supply to power transducer. Therefore my manager asked me to convert the transducer operating supply from AC,DC80~270V to 24Vdc.
*) For that I was looking the supply section of the transducer, and after bridge rectifier I found this above mentioned IC TOP242PN with Optocoupler,transformer,and some capacitors.
https://drive.google.com/file/d/1bfaBuRF-2qrTu7D3osMfOl7_ClOZsWXE/view?usp=sharing

 

Hi MZ,
Another question. Is the unit designed to be supplied by the same supply that it is measuring ? Also what are the output voltages from the switch mode power supply in your unit ? I am thinking that an isolated DC to DC converter might be a solution.
Edit I have just noticed post #9 The isolated Dc to DC converter powering the electonics directly does not look to be a practical solution.
Les.

 

Hi MZ,
Another question. Is the unit designed to be supplied by the same supply that it is measuring ? Also what are the output voltages from the switch mode power supply in your unit ? I am thinking that an isolated DC to DC converter might be a solution.
Edit I have just noticed post #9 The isolated Dc to DC converter powering the electonics directly does not look to be a practical solution.
Les.

It is measuring from Tacho-generator. Wait let me check output voltages .