Electricity: power supply or regulation systems – In shunt with source or load – Using a three or more terminal semiconductive device
Reexamination Certificate
2001-08-27
2003-01-21
Riley, Shawn (Department: 2838)
Electricity: power supply or regulation systems
In shunt with source or load
Using a three or more terminal semiconductive device
C323S283000, C361S018000, C361S093900, C361S101000
Reexamination Certificate
active
06509721
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention generally relates to electronic devices, and more particularly to buck converters.
Buck converters are used to convert a higher voltage to a lower voltage suitable for use by, for example, a microprocessor. A conventional buck converter is disclosed in U.S. Pat. No. 6,166,528, issued to Rossetti et al. on Dec. 26, 2000, the disclosures of which are hereby incorporated by reference. Typically, a buck converter operates using a clock, whereby an inductor is charged during a first portion of a clock cycle (“charging phase”) and operates as a current source during the second portion of the clock cycle (“discharging phase”).
FIG. 1A
, shows a typical buck converter
10
, which includes transistors
14
and
18
, a controller
20
, an inductor
24
and a capacitor
28
. Buck converter
10
operates by commencing the charging phase in response to a clock signal. During the charging phase, inductor
24
, capacitor
28
and a load (not shown) connected at the output voltage Vout are coupled to an input voltage Vin. Meanwhile, the inductor current i
L
is monitored by controller
20
. When i
L
peaks at a predetermined value, converter
10
is decoupled from the input voltage Vin and inductor
24
discharges its energy through the and capacitor
28
. The inductor current i
L
rises and falls linearly with slope of di
L
/dt=(V
L
/L), where V
L
is the voltage across the inductor.
FIG. 1B
shows Vin and i
L
signals in buck converter
10
.
When there is a rapid reduction in load current demand, controller
20
simply waits while the current in inductor
24
discharges into capacitor
28
and the remaining load causing a rapid increase in the output voltage Vout. For example, microprocessors, such as Pentium® and Itanium® require voltages near 1.5 V and currents near 60 A and the current changes from 0 to 60 A and back in nanoseconds. Such an increase in Vout can result in serious damage to capacitor
28
and/or the load. Therefore, the capacitor must have a very large value to limit the voltage rise to a “safe” amount during such a rapid current surge. Capacitors with large values, however, are much more expensive and are among the most expensive components in a buck converter. This increases the overall cost of a buck converter.
Therefore, there is a need for a low cost buck converter without degrading its performance.
SUMMARY OF THE INVENTION
The present invention provides a low cost buck converter without compromising the performance. According to an embodiment of the invention, a buck converter comprises an input circuit for receiving an input signal, a controller connected to the input circuit for controlling the input circuit, a switch controllable by the controller for switching on/off, a current storage element connected to the input circuit and connected in parallel with the switch, and an output voltage storage element, connected to the current storage element, for connecting in parallel with a load.
According to one aspect of the embodiment of the invention, in a charging phase, the controller causes the input circuit to allow the input signal to pass through and be provided to a load via the current storage element. The controller also causes the switch to switch off and become an open circuit.
According to another aspect of the embodiment of the invention, in a discharging phase, the controller causes the input circuit to decouple from the input signal and causes the switch to switch on and become a short circuit, so that current flows within a loop formed by the switch and the current storage element.
According to a further aspect of the embodiment of the invention, the discharging phase occurs when the controller detects a rapid decrease in a load current flowing into the load. The discharging phase also occurs when the controller detects an over voltage condition at the output voltage storage element.
Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 3641422 (1972-02-01), Farnsworth et al.
patent: 4200813 (1980-04-01), Van Schaik et al.
patent: 4814685 (1989-03-01), Renger
patent: 6107786 (2000-08-01), Brown
patent: 6166528 (2000-12-01), Rossetti et al.
patent: 6188206 (2001-02-01), Nguyen et al.
Koninklijke Philips Electronics , N.V.
Riley Shawn
Schmitt Michael E.
LandOfFree
Buck regulator with ability to handle rapid reduction of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Buck regulator with ability to handle rapid reduction of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Buck regulator with ability to handle rapid reduction of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3034941