TPS54340: doubt about PMP4369 design

Manuel Calmaestra

Part Number: TPS54340

Hello,

I understand perfectly the operation of the level shifting control block from your application note, but I don´t understand the operation of this circuit block:

Could you explain me in detail its operation? Thanks!

over 5 years ago

0 Ambreesh Tripathi over 5 years ago

TI__Expert 6860 points

Manuel ,

The thread was already answered here . https://e2e.ti.com/support/power-management/f/196/t/839947

This is an output overvoltage protection circuit ie if output exceeds below - 13V , the device Switching will be disabled .

if the output is below -13V , Q27 turns on and that pulls the enable to low state , thereby disabling the output .

---Ambreesh

0 Andy Chen over 5 years ago

TI__Mastermind 27345 points

Hi Manuel,

Just more comments: transistor Q27 and Q28 works as SCR (Silicon Controller Rectifier) device, you can find many design notes to describe this configuration. the SCR gate is connected to D2, so if negative Vout goes below -13V, break down current on D2 will trig SCR and hold EN to U1 ground till you turn-off Vin.

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TPS54340: doubt about PMP4369 design