Two proposals are made for power supply systems comprising at least one resonant inverter and one control unit. According to the first proposal the power supply system comprises two inverters and produces two output voltages, the control circuit processing as an actual value on the one hand the sum of and on the other hand the difference between the two output voltages. According to the second proposal a control circuit does not directly process the controlled variables for a power supply system...

The present invention is a circuit and method for reducing switching and reverse recovery losses in the output rectifiers while creating zero voltage switching conditions for the primary switchers. There are described two output configurations, one employing a soft commutation inductor element a bridge rectifier and a output filter capacitor, the second using a soft commutation inductor element a rectification-filtering bridge composed by two capacitors and two capacitors. Both secondary circuit...

A low drop-out voltage regulator uses a voltage subtractor circuit 36 to form a power supply rejection boost circuit. The voltage subtractor 36 is inserted between the pass element 20 and the amplifier 26 of the low drop-out regulator. The voltage regulator circuit includes a pass element 20 coupled between an input node and an output node; a voltage feedback circuit 28 and 30 coupled to the output node Vo; an amplifier 26 having an input coupled to the voltage feedback circuit; and a voltage su...

A power supply device has a reference voltage generator for generating a reference voltage, a monitor voltage generator for generating a monitor voltage that varies according to an output voltage, an output controller for producing the output voltage from an input voltage in such a way that the monitor voltage is kept equal to the reference voltage and then supplying the output voltage to a load, and a reference voltage adjuster for varying the reference voltage according to the monitor voltage....

In a switching power supply of the present invention, when a voltage output from start-up means is greater than a driving voltage produced by output means, the voltage from the start-up means is provided to control means, whereby the switching power supply can be started up reliably. Furthermore, when the voltage output from the start-up means is less than the driving voltage produced by the output means, the current path is blocked in the start-up means so that no voltage is provided to the con...

A switching power supply unit includes a transformer including a primary winding, a secondary winding, and a feedback winding; an input power supply and a first switching element that are connected in series with the primary winding; a control circuit provided between one end of the feedback winding and a control terminal of the first switching element; a rectification circuit connected to the secondary winding; and an output voltage detection circuit for detecting output voltage output from the...

An isolated boost converter includes first and second switches that are switched simultaneously, a transformer and an energy storage capacitor on the primary side of the transformer for storing energy received from input power source. In one embodiment, when the first and second switches are closed, the energy in the capacitor is transferred to the output load while a boost inductor is charged, and when the first and second switches are open, the boost inductor provides energy from the input vol...

A power supply includes a storage capacitor which can be charged with a rectified input current by means of a current-limiting element which is controlled by a drive circuit. The direct-axis component of current and the direct-axis component of voltage on the current limiting element are supplied to the control circuit as input values and the current limiting element is controlled in such a way that it is not subjected to more than a predetermined maximum power loss.

The present invention can be employed with any power supply circuit where it is desirable to employ a ratio adaptive, gated oscillator based step up switching regulator with a selectable duty cycle. By selecting a particular value for a capacitor coupled between the regulator's Frequency and Switch pins, a user can optimize the regulator's duty cycle for a particular application. Also, by adding a resistor in series with the capacitor, a time constant is created that limits the total charge tran...

The present invention discloses a PFC-PWM controller having interleaved switching. A PFC stage generates a PFC signal for switching a PFC boost converter of a power converter. A PWM stage generates a PWM signal for switching a DC-to-DC converter of the power converter. The PFC-PWM controller includes a power manager for generating a discharge current and a burst-signal. Under light-load conditions, the discharge current decreases in proportion to a load of the power converter. The burst signal i...