A switched mode power converter includes a transformer having a primary winding and at least one secondary winding, a primary side power switch coupled to the primary winding and adapted to periodically apply an input voltage to the primary winding, and an output filter operatively coupled to the secondary winding to provide an output voltage and output current. First and second active switch devices are operatively coupled in series between the secondary winding and the output filter, and a third active switch device is operatively coupled in shunt with the secondary winding and the output filter. The first and second active switches are arranged such that in an inactivated state each one blocks current between the secondary winding and the output filter in an opposite direction. A control circuit is coupled to the first, second and third active switches. The control circuit activates the first and second active switches synchronously with a first voltage state of the primary and secondary windings and activates the third active switch synchronously with a second voltage state of the primary and secondary windings. The control circuit modulates the activation time of the first and second active switches to regulate at least one of the output voltage and the output current.
RELATED APPLICATION DATA
This patent application claims priority pursuant to 35 U.S.C. .sctn. 119(e) to provisional patent application Ser. No. 60/439,971, filed Jan. 13, 2003.
A DC-AC converter for converting DC voltage to AC voltage. The converter includes a conversion circuit for converting DC voltage to voltage having a polarity corresponding to AC voltage. A filter circuit receives the converted voltage, smoothes the converted voltage, and outputs the smoothed voltage as AC voltage. A first switch operably connects the voltage conversion circuit and filter circuit. A second switch is arranged between input terminals of the filter circuit. An output current detection circuit detects overcurrent that is greater than a predetermined first threshold. When overcurrent that is greater than the first threshold is detected, the protection circuit stops the supply of power in the voltage conversion circuit, deactivates the first switch, and activates the second switch.
A multi-output switching power supply may include a PWM regulator circuit arranged in cascade upstream of each output to receive, as an input, a square wave voltage signal with a predetermined duty cycle. The regulator circuit may include an auxiliary switching device for modulating the duty cycle of the input signal to supply, as an output, a regulated direct current voltage. A control circuit for the PWM regulator circuit may include a detector circuit for detecting the trailing edges of the voltage signal input to the regulator circuit which emits a pulse coinciding with each of the trailing edges. The control circuit may also include a ramp signal generator that is controlled by the emitted pulses. The ramp signal generator may be connected to the non-inverting input of a comparator having an inverting input for receiving a signal indicative of the error in the regulator output voltage.
In a DC regulated power supply realized as AC adapter or the like by a switching power supply, a reference voltage correction circuit, which estimates a voltage drop corresponding to a load current, corrects to increase an output voltage by changing a feedback reference value for regulation of the output voltage from a reference voltage source, in accordance with the load current sensed by the load current sensing circuit. Therefore, there occurs no negative effects that would be caused when output sensing wires are routed to a remote load. In addition, unlike the arrangement in which a reference-use rectifying circuit as well as a load-use rectifying circuit are provided, the arrangement of the switching power supply is not complicated. That is, in correcting a voltage drop, which occurs in power supply lines, corresponding to the load current, it is possible to easily perform a stable output voltage control unaffected by wire routing.
7501715 - Multi-output DC-DC converter - Owned by Delta Electronics, Inc. (Taoyuan Hsien,TW) Delta Electronics (Thailand) Public Company, Limited (Samutprakarn,TH)
A multi-output DC-DC converter is advantageous over the conventional multi-output DC-DC converter in terms of increased power efficiency and power density. The inventive multi-output DC-DC converter is characterized by that the rectifying circuit located at the output stage of the DC-DC converter is implemented by a pair of self-driven synchronous rectifier transistors that can prevent a reverse current from flowing through the switch elements of the DC-DC converter. Also, a plurality of post voltage regulators are tapped to a secondary winding of the DC-DC converter, in which each post voltage regulator includes a voltage level shifter circuit for allowing gate drivers to impose a small amount of dead time on the control pulse signals for driving the internal transistor switches to minimize the dead time loss occurred during power conversion operation.
A power converter includes an input circuit that receives DC input power and creates high frequency pulses. A transformer transforms the high frequency pulses into at least two sets of transformed pulses having alternating and opposite polarity. An output circuit connected to the transformer includes a plurality of switches for blocking undesired pulses. A controller controls the switches so that they are on except when blocking undesired pulses, so that a continuous current path is provided through the output circuit.
