ADP2300 - can I use 'EN' PIN to connect to external PWM source (~20kHz)?

Hello,

I would like to use 'EN' pin to control externally the output by connect it to 50% PWN source (uP 3.3V).

And switch to PWM 100% only in specific cases.

The external PWM source will have constant frequency  ~20kHz.

May i connect it to 'EN" without any consequences?

The output voltage will be set to 2V and current shall be ~300mA.at that voltage

best regards

M.M.

  • 0
    •  Analog Employees 
    on May 25, 2021 12:57 AM

    Hi M.M.,

    I believe you can connect 20kHz signal into EN pin that will turn-on and off the converter switching to that rate. But the concern I am seeing is about what you intend to achieve at the output or the response of output voltage to that rate of turn on/off through EN signal. The output voltage can't change that fast from regulation to zero volt and back or vice-versa. Soft-start time (zero Vout to regulation) is already 1.46ms. If you want to turn-on and off the output in the same rate as the EN signal, you may not be able to do it.

    Please simulate what you want to achieve in LTspice.

  • Hi Fil,

    the idea is to use this ADP2300 as led driver with constant voltage 2V and to use EN pin to dim the led (external PWM source). ADP2300 has small package and for me it is ideal to use.

    Maybe I can reduce extenal PWM to 500Hz?

    best regards

    M.M.

  • 0
    •  Analog Employees 
    on May 25, 2021 8:54 AM in reply to MaciekM

    Hi M.M.,

    Maybe or even lower. Please check in simulation or in bench. You may connect to local ADI FAE to get you a demo board or you send me private note with project details so I can send you board.