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LM63625-Q1: Accuracy of Vout between CCM and Auto Mode

Part Number: LM63625-Q1

Hello team,

1. LM63625-Q1 has two data for Vout accuracy. Does CCM mean constant current mode, right?

2. Also does the difference between "CCM" and "AUTO mode" affect the accuracy of the Feedback voltage?

Best regards,

Shotaro

  • Hi Sakai-san, 

    1. CCM means continuous conduction mode in this case (FPWM operation vs the part going into DCM or PFM operation). 

    2. AUTO PFM you have lower switching frequency, more ripple, and the VOUT regulation is a bit wider at light load. 

    Cheers, 
    Denislav

  • Hello Shotaro,

    Thank you for your questions.

    The term CCM stands for continuous conduction mode. In this mode the ripple current flowing in the inductor is always positive. In this mode the LM63625 operates in constant frequency PWM mode.

    The LM63625 has the option to select FPWM mode (forced PWM) or Auto mode (PFM at light load and PWM at higher loads). This can be selected using SYNC/MODE pin of the device.

    When operating in Auto mode, at light load (PFM), the device supplies bursts of energy to the load when required, not at a constant frequency. In this mode, the feedback accuracy can be higher at light loads. See section 8.4.1 and figures 37 & 38 of the LM63625 datasheet for a better explanation.

    Regards, Jason