Switching regulator with advanced slope compensation
View Patent ↗A switching regulator circuit with improved slope compensation for providing a regulated voltage to a load. The regulator circuit includes a power source and a switch circuit configured to control the coupling of the power source to the load. The operation of the switch circuit is controlled by a control signal generated by a control circuit. A feedback circuit is provided for generating a feedback signal indicative of the regulated voltage provided by the switching regulator circuit to the load. A circuit is provided to generate a sensed signal indicative of the current supplied by the power source. The regulator circuit further includes a timing signal generator for generating a timing signal, a ramp signal generator for generating a ramp signal, and a current source controlled by the ramp signal for generating a compensation signal indicative of the ramp signal. The control circuit generates the control signal based on the compensation signal, the timing signal, the sensed signal and the feedback signal.
1. A switching regulator circuit for providing a regulated voltage to a load, comprising:
a power source;
a switch circuit configured to control supply of power from the power source to the load;
a feedback circuit for generating a feedback signal indicative of the regulated voltage;
a timing signal generator for generating a timing signal;
a ramp signal generator for generating a ramp signal;
a sensed signal circuit for generating a sensed signal indicative of the current supplied by the power source;
a current source controlled by the ramp signal for generating a compensation signal indicative of the ramp signal; and
a control circuit, coupled to the current source, the timing signal generator, the feedback circuit and the sensed signal circuit, for generating a control signal based on the timing signal, the compensation signal, the sensed signal and the feedback signal, to control the switching of the switch circuit,
wherein the power source and the load are coupled to a common terminal,
the control circuit subtracts the compensation signal from a signal varying with the difference between a reference signal and the feedback signal, and
the compensation signal couples to the signal varying with the difference between the feedback signal and the reference signal via a loop filter comprising a capacitor and a resistor, wherein the resistor couples to the common terminal via a DC voltage source.
2. The switching regulator circuit of claim 1 , wherein the capacitor and the resistor are connected in series, and the compensation signal is applied to the resistor or couples to a node between the capacitor and the resistor.
3. A slope compensation method for controlling the operation of a switching regulator circuit including a switch circuit for controlling the supply of regulated voltage from a power source to a load, the method comprising the steps of:
generating a feedback signal indicative of the regulated voltage;
generating a sensed signal indicative of the current supplied by the power source;
generating a timing signal;
generating a ramp signal;
providing a current source controlled by the ramp signal for generating a compensation signal indicative of the ramp signal;
generating a control signal based on the compensation signal, the timing signal, the sensed signal and the feedback signal, to control the switching of the switch circuit;
generating a signal varying with the difference between the feedback signal and a reference signal;
subtracting the compensation signal from the signal varying with the difference between the feedback signal and the reference signal; and
coupling the compensation signal to the signal varying with the difference between the feedback signal and the reference signal via a loop filter comprising a capacitor and a resistor, wherein the resistor couples to ground via a DC voltage source.
4. The method of claim 3 , wherein the capacitor and the resistor are connected in series, and the compensation signal is applied to the resistor or couples to a node between the capacitor and the resistor.