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LM76002: Switch the operating mode & sync pin

Taku Murayama
Intellectual 1260 points
Part Number: LM76002

①The LM76002 can switch the operating mode (PFM/PWM/external signal sync) by the signal to the "sync" pin. Is it possible to switch the operating mode when the LM76002 is operating?
Specifically
When a logic L is applied to the sync pin and the IC internal oscillator is operating in PFM mode, switching the given signal to a 900 kHz square wave will switch to the operation synchronized to this signal.
・ When a 900kHz square wave is given and this signal is stopped and logic L is given, the IC-built oscillator switches to PFM mode operation.

② when a 900kHz square wave is applied to the "sync" pin of the LM76002 and PWM operation is synchronized to this signal, PWM operation is maintained even when the load on the LM76002 is reduced?
Some DC-DC ICs in the world operate pulse skipping in such cases. I want to know how the LM76002 works.

  • 0
    TI__Genius 12505 points

    Hi Taku,

    Thank you for your questions. Once the devie is synced to an external clock signal it should operate at that switching frequency. When the logic to the sync pin fails, the device will continue to operate at the frequency set by the RT resistor after a certain time-out period. When the Sync pin is not used it should be grounded. More information can be found in section 7.3.7 of the datasheet.

    When the load is reduced, the device will stay in PWM operation as long as the device is still synced.

    Thank you,

    Joshua Austria