Patent ID: 8107264

Claim:
A slope compensation circuit for a peak current control mode power converter circuit, wherein the peak current control mode power converter circuit has a first forward converter, a second forward converter and a pulse width modulation (PWM) controller for controlling the first and second forward converters, wherein the first forward converter has a first high frequency transformer and a first primary switch serial connected to a primary side of the first high frequency transformer; and the second forward converter has a second high frequency transformer and a second primary switch serial connected to a primary side of the second high frequency transformer, wherein the slope compensation circuit comprises: a first charging circuit having two resistors to be serial connected to form a first serial connected resistor and a capacitor, wherein two terminals of the first serial connected resistor are respectively coupled to a first terminal of the capacitor and a first DC power source, wherein a second terminal of the capacitor is coupled to a plurality of output voltage feedback terminals of the PWM controller; a second charging circuit having two resistors to be serial connected to form a second serial connected resistor, wherein the second serial connected resistor is parallel connected to the first serial connected resistor; and a discharging circuit having a third electronic switch coupled to a serial connection node of the first serial connected resistor and having a control terminal coupled to a first driving signal synchronized to a switch driving signal of a control terminal of the first primary switch; and a fourth electronic switch coupled to a serial connection node of the second serial connected resistor and having a control terminal coupled to a second driving signal synchronized to a switch driving signal of a control terminal of the second primary switch, whereby the third electronic switch and the fourth electronic switch simultaneously turned on or off with the first primary switch and the second primary switch.