TPS560200: Duty cycle tweaks

M.A.M

Part Number: TPS560200
Other Parts Discussed in Thread: TLV62585, TPS62821, LM3691,

Hi,

With 4.75V input and 3.3V output (150mA load) the duty cycle seems to cross 70% and this does not seem supported. Down to 4.9V input, the simulation in Webench will be OK, but not lower than that. Can anything be done on the passives on the output that can make us meet our goal?

Please elaborate what device feature is limiting this scenario.

Thanks. /M.A.M

over 7 years ago

0 Chris Glaser over 7 years ago

TI__Guru**** 150900 points

Hi MAM,

For an input voltage this low, a lower Vin device is better suited for cost and efficiency. Have you already seen TLV62585 with its 100% mode (no duty cycle limit)?

0 M.A.M over 7 years ago in reply to Chris Glaser

TI__Expert 8805 points

Hi,
An alternative part must also be cheap, have accuracy closer to +/-1% and large pitch footprint as in the SOT23 0.95mm pitch package (not 0.5mm).
Hence LM3691 or TPS62821 are not possible for instance.

- Can you tell me what happens on the TPS560200 output when the voltage goes from 4.9V down to 4.75V? I do not see many 1% devices in SOT23...
Thanks. /M.A.M

0 Gavin Wang (Zejing) over 7 years ago in reply to M.A.M

TI__Expert 3480 points

The maximum recommended operating duty cycle is 65%. Vo will drop when duty cycle exceeds max value.

Power management

Power management forum

TPS560200: Duty cycle tweaks