HP V3000 945PM GF-go07200 通电0.01A 无3 5V电压，待机芯片TPS51120，什么问题？

会员674792 · 发表于 2013-11-6 19:38:29

本帖最后由 whero 于 2013-11-6 19:47 编辑

发一些TPS51120PDF保护截图

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TPS51120软停止“Discharge mode or ‘Soft Stop’ is always on during Faults or Disable. In this mode, an event that would cause the
switcher to be turned off (EN1 or EN2 low, OVP, UVP, UVLO) causes the output to be discharged through 10-Ω
transistor inside the VO terminal. The external rectifying MOSFET is not turned on for the soft off operation to
avoid a chance to cause negative voltage at the output. Soft-stop time constant is a function of the output
capacitance and the resistance of the discharge transistor. This discharge ensures that, upon restart, the
regulated voltage always starts from zero volts. In case a SMPS is restarted before discharge completion,
soft-stop is terminated and the switching resumes after the reference level comes back to the remaining output
voltage.”