Non-linear negative feedback switching voltage-stabilized power supply based on constant current protection

The invention discloses a non-linear negative feedback switching voltage-stabilized power supply based on constant current protection. The power supply comprises a diode rectifier U, a power amplifier P1, a transformer T, a switching filtering circuit, a power output circuit, a variable voltage feedback circuit, a pulse width modulation (PWM) controller, a sliding adjuster, a non-linear negative feedback circuit, a beam excitation type logic amplification circuit, a logic protection emitter coupling type amplification circuit and a constant current protection circuit. In the non-linear negative feedback switching voltage-stabilized power supply based on constant current protection, the non-linear characteristics of the non-linear negative feedback circuit are utilized, so that an adjustment tube is automatically at the edge of a saturation region, radio frequency interference of the circuit and outside is effectively reduced, the circuit structure is greatly simplified, and the manufacturing cost and the maintenance cost are substantially reduced. Meanwhile, through the constant current protection circuit, current input into the switching voltage-stabilized power supply can be detected, adjustment is made when the current is high, and thus, the switching voltage-stabilized power supply or subsequent electric apparatus is prevented from being damaged by overcurrent.