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TPS92513HV: how configure parallel output with TPS92513HV?

Part Number: TPS92513HV
Other Parts Discussed in Thread: PMP10222, TPS92512, TPS92513, TPS92640, LM3409, TPS92515

Customer wants to use 4 TPS92513HV to implement 4 parallel output for LED driver application, with 1A for each output. Could you please help check whether there are any reference for them? Or share some insights on how to implement this? Thank you.

  • Hello Aki,

    Since the TPS92513HV senses current at the bottom of the LED string this will not work with a single load, is this what they want to do?  The TPS92515AHV would allow parallel output operation since it sensing the inductor current.  There are other parts that are capable of higher current, is there a reason for using four TPS92513HVs for your application?

    Best Regards,

  • Dear Irwin,

    They found PMP10222 as a reference, which used TPS92512 instead. It seems that TPS92512 and TPS92513 are quite similar. Could you help address more details about it? Thank you.

  • Hello Aki,

    It appears that design is for four separate outputs.  Are you wanting to tie them all in parallel or is this four separate LED strings?  PMP10222 has four separate outputs at 1A each.  Replacing the TPS92512 with the TPS92513 would be a drop in replacement in the design.

    Best Regards,

  • Hi  Irwin,

    They want to tie them all in parallel to support 4A output. Is there anything they need to take cake?

  • Hello,

    This is not the recommended approach for driving a 4A LED load.  PMP10222 has four separate outputs as well, it was intended for four 1A channels.  There are other parts that can accomplish this such as the TPS92640/641, LM3409 as well as others in a single power stage.

    The TPS92513HV is a current source.  As it is setup on PMP10222 it could provide four current sources to one load however there may be interaction between the outputs when it is running but it should be possible.  Synchronizing them would eliminate low frequency ripple on the output which could be visible as well as reducing interaction between outputs.  The current sense needs to be setup so it returns to each TPS92513HV from it's source so it can properly regulate, PMP10222 is setup this way.

    Best Regards,

  • Hi  Irwin,

    Thank you for the support. Customer now understands TPS92513HV can not work for parallel output operation. Now they want to use TPS92515AHV  in this application. They have a concern for the operation frequency. Spec: Vin=45V, Vout:9V~40V, with the max current is limited to 2A for 9V, 1A for 40V. And it also needs to support analog dimming for 0~10V. They are not sure whether the switching frequency will increase up to MHz. Could you help address their concern?

  • Hello Aki,

    The highest frequency it will operate is based on their design.  If you have 45V input and 9V to 40V output the highest switching frequency will be when Vout is half of Vin.  The off-time varies with Vout to keep the ripple amplitude constant since the TPS92515 regulates peak current.

    An example quick calculation without losses included:

    Set up maximum switching frequency at 500 KHz.

    Choose inductor, used 33 uH, di/dt is 0.683A

    Switching frequency at 9V output is approximately 320 KHz

    Switching frequency at 40V output is approximately 198 KHz

    Switching frequency range is 198 KHz to 500 KHz.  The lowest switching frequency, when Vout is 40V, will be somewhat lower when losses are included.

    Best Regards,