DC/DC converter

摘要

In a DC/DC converter, each channel operates under digital control using nonlinear control. The time interval between the time of turning ON of the switching element 1 and the time of turning ON of each of other switching elements j (j=2, 3, . . . , N) is measured. If the measured interval is within a specified range, operation is continued without changing the ON time of the switching element j used last time. Meanwhile, if the measured interval is out of the range, the ON time of the switching element j is increased or decreased within a predetermined range to be shifted from a basic frequency. Thus, the interval between the time of turning ON of the switching element 1 and the time of turning ON of the switching element j is brought back to the specified range.

主权项

1. A two- or more-channel digitally controlled step-down DC/DC converter using fixed ON-time nonlinear control, comprising:
switching power supply circuits of first to N-th (where N is an integer not less than 2) channels, the switching power supply circuits being connected to an input terminal in parallel; A/D converters for converting output voltages outputted from output terminals of the switching power supply circuits of the respective channels to digital signals; and an arithmetic processing unit receiving the digital signals converted by the A/D converters, wherein each of the switching power supply circuit includes
a switching element having a first terminal connected to the input terminal to be turned on and off;an inductor having a first terminal connected to a second terminal of the switching element;a capacitor connected between a second terminal of the inductor and 0 volt; anda driving circuit for driving the switching element, and wherein the arithmetic processing unit is configured to measure a time interval between a time at which the switching element of the switching power supply circuit of the first channel has been turned ON and a time at which the switching element of the switching power supply circuit of the relevant one of the second to N-th channels has been turned ON, in case where the arithmetic processing unit determines that the switching element of the switching power supply circuit of each of the second to N-th channels has been turned ON, and,
if the measured time interval is within a specified range, the arithmetic processing unit continues operation without changing an ON time of the switching power supply circuit used last time, butif the measured time interval is out of the specified range, the arithmetic processing unit increases or decreases the ON time of the switching element within a specified time range and continues operation so that the time interval may be brought back to the specified range, thereby shifting phases of switching of the switching elements of the power supply circuits of the respective channels to reduce overlaps between the ON times of the switching elements of the respective channels.