switching power supply stability cipher scheme

  
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As everyone knows, any closed loop system is unit gain to noise temperature ratio l in the gain to noise temperature ratio, the phase shift that and inside varies with frequency is at the time of the 360 deg, there will all not be possibility in this closed loop control system. So there is a loop-locked feedback control system in almost all the sw
switching power supply stability cipher scheme - schematic

itching power supplies, thus can obtain better characteristic. In shouldering the feedback system, the control amplifier connection mode has introduced 180 quadrature 90 willfully, if the phase place feedbacked keeps within 180 degrees, it is always stable to control the cycle. Certainly, the situation be will existed in reality, because various switch delay time and impedance lead extra phase shift into, if does not adopt the appropriate cycle to compensate, this kind of phase shift will cause the unstability of switching power supply too. The index of weighing the stability of the switching power supply is phase margin and gain margin. Phase margin refers to: The correspondent phase place when the gain to noise temperature ratio drops to 0dB. The gain margin refers to: The phase place, for the correspondent gain magnitude actually decay at zero hour. While designing the switching power supply actually, consider the gain margin only while designing the anti exciting converter, while designing other converters, seldom use the gain margin. In the switching power supply design, there are two to act on phase margin separately: First, the dynamic procedure that can appear in the step change of load with the damping converter; Another function change as yuans of device parameter, permitted security system steady still. Phase margin can only be used for guaranteeing  The dwarf signal is steady . While supporting the step...



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