TPS5401: Need an AC-DC converter

Shibin Varghese

Part Number: TPS5401

Hi, support,
I am looking for a cheaper AC-DC converter and thus I came across TPS5401 of Texas Instruments.

I need a circuit with a 3.6V output voltage with a 300mA output current from a single-phase AC supply.

The output of TPS5401 is 500mA, but as per the application note SLVA491, the output of the circuit is only 50mA.

The maximum input voltage of TPS5401 is 42V.

Does this mean a 300mA output current is not possible with this chip?.

How can I improve the circuit to get 300mA output current?.

over 5 years ago

0 Iven Su over 5 years ago

TI__Expert 8245 points

Hi,

50mA is not the max load capability but just a design requirement in the application note. You can follow design procedure in 8th sector in its datasheet.

0 Shibin Varghese over 5 years ago in reply to Iven Su

Expert 1130 points

Hi,

Thank you for your reply.
As per the datasheet of TPS5401, the output voltage is set by

And the only equation for output current is

where Cin is the decoupling capacitor at Vin pin of the chip.
As per the hardware implementation of single-phase E mater

https://www.ti.com/lit/an/slaa517e/slaa517e.pdf?ts=1597900395842&ref_url=https%253A%252F%252Fwww.google.com%252F

But I cannot find a single equation connecting the capacitor or resistor value with the output current.
Looking forward to your reply

Also, my device will enter sleep mode and the power consumption will be about 6uA in sleep mode. Will this affect the performance of the power supply?

0 Iven Su over 5 years ago in reply to Shibin Varghese

TI__Expert 8245 points

Hi,

Output current is not mainly determined by inductor and capacitor but by output voltage and load resistor if the load is within the device's load capability. Sleep mode is a normal working mode which won't affect its performance.

0 Shibin Varghese over 5 years ago in reply to Iven Su

Expert 1130 points

Hi Iven,
Thank you for your reply.
Your answer is very helpful.
The maximum output current of the chip is 500mA.
My load will the just above 100mA so I am fine with the application circuit provided in the datasheet.
My doubt is how to control the output current of the chip.
We can vary the output voltage by changing the voltage at the Vsense pin.

Likewise, how can I vary the output current?.

0 Shibin Varghese over 5 years ago in reply to Shibin Varghese

Expert 1130 points

Awaiting your reply!!!!!!!!!!!!!!!!!!!!!!!!!!!

0 Iven Su over 5 years ago in reply to Shibin Varghese

TI__Expert 8245 points

Hi,

The device only controls output voltage, if no current limit triggered, the output current is determined by your load following Ohm's law : Iload = Vout / Rload.

0 Shibin Varghese over 4 years ago in reply to Iven Su

Expert 1130 points

Hi,

Thank You for your reply.

I'm attaching a circuit I've just created with TPS5401 herewith.
I want a 24V output voltage with a 200mA output current. The input is 230VAC.

Did I make any mistake in the calculation?
Awaiting your reply.

0 Iven Su over 4 years ago in reply to Shibin Varghese

TI__Expert 8245 points

Hi,

You can't use a 230VAC input as this device has a 47VDC max input.

0 Shibin Varghese over 4 years ago in reply to Iven Su

Expert 1130 points

Hi,

In the circuit, I am using a Zener diode of 39V, so the maximum input will be 39V.
A cap drop power supply is used at the input.

0 Iven Su over 4 years ago in reply to Shibin Varghese

TI__Expert 8245 points

Hi,

I don't think a 39V Zener diode can handle a constant 230VAC input volatge, the diode will damage. You could modify your schematic and re-design it by Webench tool:

www.ti.com/.../design-tools-simulation.html

0 Shibin Varghese over 4 years ago in reply to Iven Su

Expert 1130 points

Hi,

The circuit I've provided is from TI's application note SLVA491

0 Shibin Varghese over 4 years ago in reply to Iven Su

Expert 1130 points

Hi,
I found this circuit from TI's application note SLVA491.
Here a cap drop power supply is used just prior to the Zener diode.

0 Iven Su over 4 years ago in reply to Shibin Varghese

TI__Expert 8245 points

Hi,

I see, if you use a blocking capacitor in series at input, the above schematic is OK.

0 Shibin Varghese over 4 years ago in reply to Iven Su

Expert 1130 points

Yes, We are using a series capacitor just prior to the Zener diode.
My doubt is the output current of the application circuit provided.

0 Iven Su over 4 years ago in reply to Shibin Varghese

TI__Expert 8245 points

Hi,

I think the 50mA is design requirement not current capability. The device supports 0.5A load current and the schematic is good to deliver higher than 50mA if inductor and diode selection is reasonable.

Power management

Power management forum

TPS5401: Need an AC-DC converter