Controller and adjustment and control method for controller

Abstract

The invention discloses a controller. The controller comprises a switch tube, a first hysteresis comparator, a second hysteresis comparator, a pulse width modulation (PWM) comparator, a control signal (CS) comparator, an or gate and a logic controller, wherein the switch tube controls work of a transformer; the first hysteresis comparator compares a comparator (COMP) signal with load threshold value Vref1 and outputs a burst signal; the second hysteresis comparator compares a source voltage VCC with a power threshold value Vref2 and outputs a hold signal; a control end of the PWM comparator is connected with the burst signal, and an output end is connected with the logic controller; an output end of the CS comparator is connected with the logic controller; two input ends of the or gate are connected with the hold signal and the burst signal respectively and output a control signal (control) to the logic controller; the logic controller controls the switch tube; and when COMP is less than Vref1 and VCC is less than Vref2, the controller works in a holdup mode, the PWM comparator is shielded, the comparison level of the CS comparator is low level, and the switch tube has output and keeps the power voltage VCC over under-voltage locking voltage. The invention also discloses an adjustment and control method for the controller. The adjustment and control method has a good power-saving effect.

Description

technical field [0001] The invention relates to the technical field of controllers, more specifically, to a controller capable of reducing static loss under light load conditions and a control method based on the controller. Background technique [0002] When the controller works under light load conditions, the operating frequency will generally be reduced to reduce switching losses. When the load is further reduced, or even there is no load, and the controller does not output PWM waveforms, it generally no longer supplies power to the control chip. Although there is no switching loss at this time, there is power consumption inside the control, so the power supply voltage of the control chip starts When it drops to undervoltage, the control chip starts to lock the level, so that the controller enters the restart state. [0003] see figure 1 , showing the existing controller structure. Among them, the control chip 100 is included, the optocoupler 112 transmits the COMP si...

AI Technical Summary

Problems solved by technology

[0004] When the controller works in the light-load frequency hopping mode, the control chip 100 does not output PWM waveforms, and the auxiliary winding of the transformer 109 no longer supplies power to the power supply capacitor 103. Although there is no switching loss at this time, there is power consumption inside the control chip 100, so the control The power supply voltage VCC of the chip 100 starts to drop

Generally, the time constant of the power supply capacitor 103 is smaller than the time constant of the output capacitor 113, so the power supply voltage VCC drops faster. When the power supply voltage VCC is lower than the undervoltage lockout level (UVLO), the controller restarts state, affect the use of

Images