초록 ▼

Disclosed is an active power factor correction integrated circuit for a boost converter, comprising a bias voltage generator coupled to an external power source through a first pin, for generating internal bias voltages used for the integrated circuit; a zero crossing detector coupled magnetically t

Disclosed is an active power factor correction integrated circuit for a boost converter, comprising a bias voltage generator coupled to an external power source through a first pin, for generating internal bias voltages used for the integrated circuit; a zero crossing detector coupled magnetically to the inductor through a second pin, for detecting a time at which a voltage across the inductor is zero to provide a zero crossing detection signal; an oscillator reset by the zero crossing detection signal for generating a pulse signal; a flip-flop for generating a first control signal in response to the zero crossing detection signal or the pulse signal; a switching element responsive to the first control signal for enabling a boosted voltage to be provided to the load; an over-current detector for generating an over-current signal when a current flowing through the switching element is over a predetermined value; and a voltage variation detector for detecting variation of a load voltage to generate a variation detection signal and generating a second control signal enabling the boosted voltage to flow through the switching element to a ground in response to both the variation detection signal and the over-current signal. With the integrated circuit, the number of the IC pin and the number of the peripheral components thereof may be considerably reduced.

대표청구항 ▼

[ What is claimed is:] [1.] An active power factor correction integrated circuit for correcting a power factor of a boost converter having a rectifier for transforming AC into DC and an inductor coupled between the rectifier and a load, the integrated circuit comprising:a bias voltage generator conf

[ What is claimed is:] [1.] An active power factor correction integrated circuit for correcting a power factor of a boost converter having a rectifier for transforming AC into DC and an inductor coupled between the rectifier and a load, the integrated circuit comprising:a bias voltage generator configured to be coupled to an external power source through a first pin, wherein the generator is further configured to generate internal bias voltages used within the integrated circuit;a zero crossing detector configured to be coupled magnetically to the inductor through a second pin, wherein the zero crossing detector is further configured to detect a time at which a voltage across the inductor is zero and generate a zero crossing detection signal responsive thereto;an oscillator configured to be reset by the zero crossing detection signal wherein the oscillator is further configured to generate a pulse signal;means for generating a first control signal in response to one of the zero crossing detection signal and the pulse signal;switching means responsive to the first control signal configured to be coupled to the load through third and fourth pins and further configured for enabling a boosted voltage to be provided to the load;means for generating an over-current signal when a current flowing through the switching means is over a predetermined value; andmeans for detecting variation of a load voltage configured to be coupled to the load through a fifth pin wherein the means for detecting is further configured to generate a variation detection signal responsive to a sense voltage present at the fifth pin and is still further configured to generate a second control signal enabling the boosted voltage to flow through the switching element to a ground in response to both the variation detection signal and the over current-signal.