电脑电源芯片类似TPS51117 输出为什么用两个相同的N-mos呢，帮忙解答一下.....

什么支架

是为了什么才采取了上下管输出的方式？
上下管分别在什么时候工作？

la45088d1

    Before presenting any questions, you'd better read the datasheet which is issued by the manufacturer carefully, all the details will be demonstrated on it.
Here are several sentences from the datasheet that may be helpful:
    At the beginning of each cycle, the synchronous high-side MOSFET is turned on, or becomes ON-state. This MOSFET is turned off, or becomes OFF-state, after the internal one-shot timer expires. This one-shot is determined by VIN and VOUT to keep the frequency fairly constant over the input voltage range at steady-state, hence it is called adaptive on-time control or fixed frequency emulated on-time control (see PWM Frequency and Adaptive On-Time Control). The MOSFET is turned on again when both feedback information, monitored at VFB voltage, indicates insufficient output voltage and inductor current information indicates below the overcurrent limit. Repeating the operation in this manner, the controller regulates the output voltage. The synchronous lowside or rectifying MOSFET is turned on each OFF-state to keep the conduction loss to a minimum.

la45088d1

    In a traditional Buck converter architecture, a Schottky Diode is needed to conduct the current when the high side MOSFET is off. Although a specific Schottky Diode owns the so-called low dropout voltage feature, it still causes a remarkable power loss when the operating current is very high. In order to reduce more power loss, a low side MOSFET is applied to the circuit to act as a ideal diode. Concerning that the on resistance of the MOSFET is generally very low so the power loss is dramatically reduced. The technology is called synchronous rectification.

什么支架

la45088d1 发表于 2019-12-15 01:05
In a traditional Buck converter architecture, a Schottky Diode is needed to conduct the current  ...

谢谢朋友的回复，看这个回复的意思是，这里不光的下管是负责在上管off状态下提供延续而平缓的电压电流用的，是因为输出的并非直流源，在一定意义上讲，下管在这里起到的并非是开关作用，更多的是从输出电源品质上来考虑，也就是说，双管后边必然要带着L，

orsonzou

同步整流，上下交替导通
上面导通为电感充电
下面导通为电感续流
电感为锯齿波电流
电压等于电感乘以电流在时间上的变化率。v=L*di/dt