Abstract: A control method and control circuit for a switched-mode power supply (SMPS) and a control chip are disclosed. The SMPS is switched between different operating modes based on different levels of its output voltage. When the output voltage is lower than a first reference and the difference between it and the first reference exceeds a threshold, an operating frequency of a power transistor and output voltage are controlled to satisfy a proportional relationship defined by an associated slope. When the output voltage is lower than the first reference and the difference between it and the first reference is below the threshold, the power transistor is controlled to operate at a fixed frequency. When the output voltage is higher than the first reference, the power transistor is controlled to operate at a variable frequency.

Abstract: A quick joint in a hydraulic pipeline, more particularly, a quick pipeline joint applied to a hydraulic system, where frequent disconnection or connection of liquid pipelines is required. In one embodiment, the quick joint in the hydraulic pipeline includes an outer joint and an inner joint. The outer joint includes an oil pipe joint, O-rings, a block, a spring, a valve rod, a plunger, a joint sleeve and other parts. The inner joint includes a plurality of O-rings, a spring seat, a joint sleeve, a spring, an oil pipe joint and other parts. The outer joint and the inner joint can be connected or disconnected easily through insertion and pull-out of a circlip.