Enable control circuit, switching power supply controller and control method

Abstract

The invention provides an enable control circuit, a switching power supply controller and a control method. The enable control circuit comprises a key switch, wherein one end of the key switch is grounded, and the other end of the key switch is connected with a KEY interface of the switching power supply controller; the KEY interface is sequentially connected with a first blanking circuit, a firsthysteresis control circuit, a trigger control circuit and the enable control circuit. The enable control circuit is simple in structure and low in cost, and has a relatively good application prospect.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to an enabling control circuit, a switching power supply controller, and a control method. Background technique [0002] Enable control, that is, a control method that requires external triggering to start. In the prior art, for switching power supplies that require enabling control, such as AC / DC power supplies, power strips with switch control functions, etc., the following methods are mainly used for control: [0003] Method 1: Use the direct switch lock button to control (such as figure 1 ), the button generally has the corresponding current on-off capability, and it can directly close the loop and turn off, but the contact is easy to age and may be accompanied by electric sparks, arcing and other discharge phenomena. operate. [0004] Method 2: Carry out intelligent switch control (such as figure 2 shown). After receiving the external trigger (switch SW1), t...

AI Technical Summary

Problems solved by technology

After receiving the external trigger (switch SW1), the switch closed loop is realized through the relay (KW1), which makes the switch operation more humanized, but the processing of external signals requires system power supply (such as image 3 The LV+, LV- low-voltage power supply additionally uses a backup power supply), resulting in excessive standby power consumption and high cost

[0005] Method 3: On the basis of method 2, use the power supply for the relay (KW1) in the standby mode of the subsequent switching power supply (such as image 3 As shown), it solves the power supply problem of LV+ and LV-, that is, using On / Off1 to control the opening and closing of the relay, which reduces the cost to a certain extent, but requires additional devices to realize On / Off2 to break the output of the switching power supply to prevent failure. The expected situation occurs, and there are still a series of problems such as excessive standby power consumption and high cost

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