US 7,453,250 B2 · PWM controller with dual-edge modulation using dual ramps

Abstract

A dual-edge modulation controller including first and second ramp circuits, first and second comparators, an error amplifier and pulse control logic. The first ramp circuit provides a leading-edge ramp synchronous with a clock. The error amplifier compares a feedback signal with a reference and provides a compensation signal. The first comparator compares the leading-edge ramp with the compensation signal and asserts a set signal. The second ramp circuit provides a trailing-edge ramp that begins ramping when the set signal is asserted. The second comparator compares the trailing-edge ramp with the compensation signal and asserts a reset signal. The pulse control logic asserts a PWM signal when the set signal is asserted and de-asserts the PWM signal when the reset signal is asserted. The controller may control multiple phases with current balancing. The slew rate of the ramps may be adjusted based on the number of PWM signal asserted.

Claims24

Dependent claims

A dual-edge modulation controller, comprising:

a first ramp circuit which provides a leading-edge ramp signal synchronous with a clock signal;
an error amplifier which compares a feedback signal with a reference signal and which provides a compensation signal indicative thereof;
a first comparator which compares said leading-edge ramp signal with said compensation signal and which asserts a set signal indicative thereof;
a second ramp circuit which provides a trailing-edge ramp signal that begins ramping when said set signal is asserted;
a second comparator which compares said trailing-edge ramp signal with said compensation signal and which asserts a reset signal indicative thereof;
and
pulse control logic which asserts a pulse-width modulation (PWM) signal when said set signal is asserted and de-asserts said PWM signal when said reset signal is asserted.

4 more elements

A power converter, comprising:

a first phase circuit controlled by a first pulse width modulation (PWM) signal for converting an input voltage to an output voltage via a first inductor;
and
a dual-edge modulation controller having a feedback input for sensing said output voltage and a first PWM output for providing said first PWM signal, said dual-edge modulation controller comprising:
an error amplifier having a first input coupled to said feedback input, a second input receiving a reference voltage and an output providing a compensation signal;
an oscillator which provides a first leading-edge ramp signal having repetitive ramps;
a first comparator which compares said first leading-edge ramp signal with said compensation signal and which asserts a first set signal indicative thereof;
a first ramp circuit which ramps a first trailing-edge ramp signal while said first PWM signal is asserted;
a second comparator which compares said first trailing-edge ramp signal with said compensation signal and which asserts a first reset signal indicative thereof;
and
first pulse control logic which asserts said first PWM signal when said first set signal is asserted and which de-asserts said first PWM signal when said first reset signal is asserted.

7 more elements

A method of controlling a DC-DC converter, comprising:

providing a first leading-edge ramp signal synchronous with a clock signal;
comparing a feedback signal with a reference signal and providing a compensation signal indicative thereof;
comparing the first leading-edge ramp signal with the compensation signal and asserting a first start signal indicative thereof;
ramping a first trailing-edge ramp signal while a first pulse-width modulation (PWM) signal is asserted;
comparing the first trailing-edge ramp signal with the compensation signal and asserting a first stop signal indicative thereof;
and
asserting the first PWM signal when the first start signal is asserted and de-asserting the first PWM signal when the first stop signal is asserted.

4 more elements

Dependencies are inferred from the claim text.

PWM controller with dual-edge modulation using dual ramps

Life of this patent

PWM controller with dual-edge modulation using dual ramps

Life of this patent

Abstract

Claims24