Electric power conversion systems – Current conversion – With means to introduce or eliminate frequency components
Reexamination Certificate
2000-06-01
2001-03-27
Berhane, Adolf Deneke (Department: 2838)
Electric power conversion systems
Current conversion
With means to introduce or eliminate frequency components
C363S021030, C363S097000
Reexamination Certificate
active
06208538
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to pulse-width modulated control apparatus, and particularly but not exclusively for such apparatus when used to control a switched-mode power supply.
BACKGROUND OF THE INVENTION
Switched-Mode Power Supplies (SMPS) are being increasingly used in many domestic and industrial applications. In applications such as televisions or computer monitors, the application may require a number of states or modes of operation. A first ‘off’ mode occurs when there is no power supplied to a device (or when a master switch is off); a second ‘on’ mode occurs when the device is switched to an operating normally; and a third mode (referred to as a standby mode) occurs when the device is to remain powered, but with reduced functions and reduced power consumption. A standby mode may be encountered in a television via an ‘off’ switch of a remote control, which typically does not switch the television fully off, but allows certain circuitry within the television to remain powered, so that if the ‘on’ button of the remote control is pressed, the television will return to the ‘on’ mode.
There is a need to reduce the power consumed by the SMPS during standby mode, so that use of mains electricity is reduced. At present there is a goal to reduce the power consumption during standby mode to a value of the order of 1 Watt.
Burst mode SPMS are known, which have an efficient power consumption in standby mode. However the PWM control apparatus are not easy to implement for burst-mode SMPS, they generate much noise due to the ‘burst’ nature of their operation, and they require a large number of connections and external components, leading to a semiconductor package having many connection pins, and a large printed circuit board with many components.
Therefore what is needed is PWM control apparatus for SMPS with a reduced number of discrete components, a reduced pin count and size, and low power consumption in standby mode.
This invention seeks to provide a power supply which mitigates the above mentioned disadvantages.
SUMMARY OF THE INVENTION
According to the present invention there is provided a PWM control apparatus as claimed in claim
1
.
In this way a PWM control apparatus for a SMPS is provided with a reduced number of discrete components, a reduced pin count and size, and a low power consumption in standby mode.
REFERENCES:
patent: 4994719 (1991-02-01), Lendaro
patent: 5017844 (1991-05-01), Lendaro
patent: 5351177 (1994-09-01), Megeid
patent: 5465011 (1995-11-01), Miller et al.
patent: 5689407 (1997-11-01), Marinus et al.
patent: 5764461 (1998-06-01), Wu
patent: 5812383 (1998-09-01), Mobers et al.
patent: 6005789 (1999-12-01), Lee
Philips Semiconductors: Greenchip SMPS module TEA1566, Data Sheet, Apr. 20, 1999 (199-04-20) XP002122143 pp 1-23.
Motorola: Greenline very high voltage PWM Controller, Data Sheet, Jul. 1999 (199-07), XP002122144 pp 1-15.
Halamik Josef
L'Hermite Francois
Turchi Joel
Atkins Robert D.
Berhane Adolf Deneke
Semiconductor Components Industries LLC
Wallace Michael T.
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