US 8,797,013 B2Granted

Adaptive slope-compensation module and method thereof

AssigneeLeadtrend Technology Corp.

InventorsHsing-Kuo Chao, Yi-Shan Chu

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Abstract

An adaptive slope-compensation method is applied for a switch-mode power supply. The switch-mode power supply has a power switch, and an inductor coupled to an input power. The power switch controls the inductor storing energy or releasing energy to generate an output voltage. The adaptive slope-compensation method includes detecting an inductor current passing through the inductor and to generate an inductor-current detecting voltage, detecting a duty cycle of the power switch, detecting a voltage variation of the inductor-current detecting voltage when the power switch is turned on, generating a slope-compensation signal according to the voltage variation and the duty cycle, and adjusting the timing of turning the power switch on or off. In this way, even if the operation conditions of the input power and the output voltage change, the system still can quickly response and does not generate sub-harmonic oscillation.

Claims17

Dependent claims

An adaptive slope-compensation method applied to a switch-mode power supply, the switch-mode power supply having a power switch and an inductor coupled to an input power, the power switch controlling the inductor to store energy or release energy to generate an output voltage, the adaptive slope-compensation method comprising:

detecting an inductor current passing through the inductor, thereby generating an inductor-current detecting voltage;
detecting a duty cycle of the power switch;
detecting a maximum and a minimum of the inductor-current detecting voltage and determining a voltage variation of the inductor-current detecting voltage according to the maximum and the minimum of the inductor-current detecting voltage when the power switch is turned on;
generating a slope-compensation signal according to the voltage variation and the duty cycle;
and
adjusting a timing to turn on or turn off the power switch according to the slope-compensation signal;
wherein detecting the maximum of the inductor-current detecting voltage comprises:
continuously comparing the inductor-current detecting voltage with a first recorded voltage when the power switch is turned on;
setting voltage level of the first recorded voltage to be equal to voltage level of the inductor-current detecting voltage when the inductor-current detecting voltage is higher than the first recorded voltage;
and
outputting the maximum of the inductor-current detecting voltage according to the first recorded voltage.

8 more elements

An adaptive slope-compensation module, applied in a switch-mode power supply, the switch-mode power supply having a switch control circuit, a power switch, an inductor coupled to an input power, and an inductor-current detecting circuit for detecting an inductor current passing through the inductor, thereby generating an inductor-current detecting voltage, the switch control circuit turning the power switch on or off to control the inductor to store energy or release energy to generate an output voltage, the adaptive slope-compensation module comprising:

a duty-cycle detecting circuit for detecting a duty cycle of the power switch;
a voltage-variation detecting circuit for detecting a voltage variation of the inductor-current detecting voltage when the power switch is turned on;
and
a slope-compensation integrating circuit for calculating a compensation slope according to the voltage variation and the duty cycle, then integrating the compensation slope to generate a slope-compensation signal;
wherein the switch control circuit determines a limiting value of the inductor current according to the slope-compensation signal, and compares the inductor current with the limiting value, thereby generating a comparing signal;
and the switch control circuit adjusts a timing to turn on or turn off the power switch according to the comparing signal.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/078,005Filed 1 Apr 2011
Priority: TW 99110327 A2 Apr 2010
Published: US 2012/0074917 A129 Mar 2012
Granted: 5 Aug 2014
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

H02M 3/155
Using devices of a triode or transistor type requiring continuous application of a control signal: using semiconductor devices only
H02M 1/0029
Details of control, feedback or regulation circuits: circuits or arrangements for limiting the slope of switching signals, e.g. slew rate
H02M
Apparatus for conversion between ac and ac, between ac and dc, or