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TPS923650: TPS923650 BOOST CONVERTER IC FAILURE ISSUE

Khushi Bansal
Prodigy 30 points
Part Number: TPS923650


Tool/software:

I am using the Boost converter IC (Part No: TPS923650D1DRLR) for a DC-DC LED Driver application, with the following specifications:

Sr. No.

Parameter

Value

1

Input Voltage

24 ± 20% VDC

2

Output Voltage

54–56 VDC (on load)

3

Output Current

165 mA (typical)

4

Dimming

PWM

5

Topology

Boost

Problems:
1. I power up the boost converter and run it at full intensity for few minutes. After recycling the input, the converter fails, either the Vin or Vcc pin of the IC gets shorted to GND.

Additionally, often after replacing the failed IC with a new one, the circuit does not work.

2.At No Load, the circuit’s no-load voltage shoots upto 80V, the Data sheet says that protection triggers when CSN>65V , Is CSN value upto 80V safe ??

However, keeping the converter at No load for few minutes even causes the IC to fail. The failure is input and output short circuit.

3. In our circuit the DIM pin is connected to Vcc at Turn ON - is this a potential reason for failure ?

Schematic for the same is attached here for reference:

  • 0
    TI__Genius 9255 points

    Hi Khushi,

    our expert is on public holiday and replay will be delayed to 5/6

    thanks 

    BR

    Monet Xu

  • 0 in reply to Monet Xu
    TI__Mastermind 31911 points

    Dear Khushi,

    Do you see correct LED voltage and current after you power up the boost converter and run it at full intensity?

    Khushi Bansal said:
    1. I power up the boost converter and run it at full intensity for few minutes. After recycling the input, the converter fails, either the Vin or Vcc pin of the IC gets shorted to GND.

    In theory, it should not shoot up to 80V. The device has LED open load protection: If CSN>65V, the device will stop switching and recovers when fault is removed.

    Khushi Bansal said:
    2.At No Load, the circuit’s no-load voltage shoots upto 80V, the Data sheet says that protection triggers when CSN>65V , Is CSN value upto 80V safe ??

    The DIM pin can be connected to Vcc.

    I would recommend that you can first check the schematic can match with the layout and check the components are placed properly on the board. And you can also apply for the EVM board and place your components to the EVM board to see whether it can work properly. 

    Thank you!

    BRs

    Lucia