| US 7,489,975 B2 | ||
| Power supply device, information processing apparatus, and power control method | ||
| Hirohito Motomiya, Saitama-Ken (Japan); and Shizuo Morioka, Saitama-Ken (Japan) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
| Filed on May 31, 2006, as Appl. No. 11/443,281. | ||
| Claims priority of application No. 2005-159569 (JP), filed on May 31, 2005. | ||
| Prior Publication US 2006/0268977 A1, Nov. 30, 2006 | ||
| Int. Cl. G06F 19/00 (2006.01) | ||
| U.S. Cl. 700—22 [700/286; 314/266] | 8 Claims |
| 1. A power supply device comprising:
a power converting unit that switches DC power on the basis of a pulse signal having a predetermined ON-pulse time and a predetermined
pulse period, as pulse elements, thereafter smoothes the switched power, and outputs a predetermined power-supply voltage;
a control unit that calculates a new pulse-element on the basis of an output of the power converting unit; and
a pulse generating unit that generates the pulse signal on the basis of the new pulse-element instructed from the control
unit,
wherein the pulse generating unit generates the pulse signal of the new pulse-element from the instructed timing without waiting
for a new pulse-period, irrespective of the ON-pulse time and an OFF-pulse time, even if the instructed timing is at any timing
during the pulse period,
wherein the pulse generating unit comprises:
a counter that inputs a predetermined clock signal and counts the number of clocks;
a pulse period storing portion that stores a value of the pulse period;
a pulse period generating portion that compares a count value of the counter with the pulse period stored in the pulse period
storing unit and resets the count value of the counter every pulse period;
a first pulse-width storing portion that stores a value of the ON-pulse time;
a second pulse-width storing portion that receives the value of the ON-pulse time transferred from the first pulse-width storing
portion and stores the value of the ON-pulse time, when the count value is reset; and
a pulse width generating portion that compares the count value of the counter with the value of the ON-pulse time stored in
the second pulse-width storing portion, determines the ON-pulse time on the basis of the comparison of both the values, and
generates the pulse signal on the basis of the determined ON-pulse time, and
wherein the control unit stores the value of the ON-pulse time to the first pulse-width storing portion,
directly stores a value of a pulse width to be changed to the second pulse-width storing portion not via the first pulse-width
storing portion, upon issuing an instruction for changing the pulse with during the ON-pulse time, and
forcedly resets the count value of the counter upon issuing the instruction for changing the pulse width during the OFF-pulse
time.
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