Other

Min-Sung Yang

Timothy Allen Pletcher

Robert Amantea

Jae-Hong Joo

Jae-Young Choi

Joo-Dong Yu

Jae-Hwan So

Bok-Man Kim

Heon-Kyu Kim

A power supply according to the principles of the inventions comprises two stages. The first stage is a power factor corrector stage. This stage provides the required line regulation, including greater than 95% power factor correction, and provides a range of outputs from approximately 5 volts to 200 volts with good load regulation at low voltages. The second stage is a soft switching power supply having good load regulation from approximately 40 to approximately 175 volts. An intermediate high voltage of the first stage supplies the input to the second stage, thereby achieving extremely good line regulation and low regulation.

Two stage architecture for a monitor power supply

A converter utilizing a multifilar transformer having its primary and auxiliary windings made simultaneously, a technique known as bifilar winding, provides high efficiency and low noise. The multifilar winding technique yields minimum leakage inductance between the windings and reduces the proximity effect to a minimum achievable using most well-known wires. The converter utilizes an improved soft-switcher topology which advantageously reduces the interwinding capacitance between the primary and auxiliary windings of the transformer. The topology includes a resonant LC circuit interposed in series with one leg of the auxiliary winding and the auxiliary switch. The other leg of the auxiliary winding is at ground. A controller is provided to control switch timing such that the converter optimizes switch loss and resonant pulse loss.

Soft-switching power supply with auxiliary resonator

An exemplary power supply provides low power dissipation in standby mode by disabling the start-up circuit and by implementing variable frequency operation independent of the feedback signal. A standby mode detection circuit automatically implements the variable frequency operation, and an under voltage lockout signal implements the start-up circuit disable. Once the start time expires or when feedback control enables, the start-up circuit is disabled so that it dissipates negligible power. A voltage controlled oscillator responsive to the rectified DC line voltage provides for variable frequency operation in standby mode. The frequency output of the VCO is inversely proportional to the line voltage&mdash;as line voltage increases the switching frequency decreases, which decreases the output power.

Low power dissipation power supply and controller

A dual mode converter is provided that may be operated as a variable-frequency, naturally-commutated controller in a Zero-Voltage-Switching mode and as a fixed-off-time controller in a Fixed-Off-Time mode. The converter includes four functional elements. A reference and biases element generates voltage references and biases utilized to determine various signal states. A Timing element generates a fixed off time signal and a voltage ramp signal utilized to create the dual modes of operation. A Catastrophic-Event element detects events that cause the converter output be inhibited and the controller to be restarted. A Mode Detection and Pulse Width Modulation element determines the mode of operation for the converter based on signal inputs from the other functional elements and modulates the output accordingly. In a primary mode, the controller utilizes variable frequency operation to deliver primary power. In a standby mode, the controller utilizes fixed frequency operation to provide low power (less than 5W).

Growing community of inventors

Seoul, South Korea

Min-Sung Yang