摘要:
A power factor controller, a method of controlling power factor and a power converter employing either the controller or the method. The controller includes: (1) a ramp circuit that senses an output voltage of a converter being controlled and generates an intermediate waveform that rises as a function of a magnitude of the output voltage and (2) a drive circuit, coupled to the ramp circuit, that senses a current in the converter and causes the intermediate waveform to fall at a time that is a function of a magnitude of the current, the drive circuit generating a drive signal for the converter from the intermediate waveform.
摘要:
A split boost converter is disclosed herein, suitable for both single phase and three phase AC input applications. It provides two equal but unparallelable output voltages stored on two separate independent output capacitors. The implementation supports two modes of operation in which two power switches are operated simultaneously or alternately. Each mode maintains the advantage of a reduced boost inductor size. In the first mode the charging of the capacitors in parallel circuits and their discharge in a series connection substantially reduces ripple current in the inductor permitting the user of a smaller inductor. In the second mode the capacitors are charged and discharged in differing time intervals achieving a similar result. The circuit is operable with input voltages which must exceed the voltages of its two output capacitors.
摘要:
A multiple output dc to dc converter is described that improves efficiency for auxiliary outputs using a secondary side switch. The converter uses a switching circuit to place an alternating voltage from a dc power source across a transformer. The switching circuit is controlled by a primary PWM controller which regulates the primary output voltage by adjusting the duty cycle of the switching circuit. The switching circuit produces an alternating voltage across the center-tapped winding of the transformer, which is rectified by diodes connected to the winding to create a full-wave output. This output is used by a primary output circuit to create the primary output voltage, and is also used to create an auxiliary output voltage by using a secondary side switch and auxiliary PWM controller to regulate the auxiliary output. A bypass element, which can be a diode, is connected between the transformer and the auxiliary output circuit to bypass the auxiliary switch during one phase of the full wave output cycle, thereby increasing the efficiency of the auxiliary output by eliminating losses due to the switch during that phase. The invention can be used with any common converter topology that uses a full wave type output, including, but not limited to, full-bridge, half-bridge, push-pull, clamped-mode forward converter, or any other topology with a full-wave rectified output.