US 7,095,215 B2 · Real-time voltage detection and protection circuit for PFC boost converters

Abstract

A circuit for providing protection for power factor correction (PFC) boost converters from conditions such as input voltage surges that can otherwise cause failure. The circuit also prevents unnecessary down time of the boost converter after a power failure or on startup. The circuit detects the real time rectified input voltage and provides a real time comparison of the detected input voltage and the output voltage. The boost function is controlled as a function of the comparison. The circuit enables the boost converter to start and restart more quickly, even before the output voltage becomes stabilized, since boost is permitted as soon as the output voltage exceeds the real time sampled input voltage. By enabling boost during this period, the circuit eliminates the need to wait at least a few cycle times until the output voltage is higher than the peak of rectified input voltage.

Claims16

Dependent claims

A circuit for providing protection for a boost converter during power disturbance conditions affecting the boost converter's input voltage, said boost converter having a switch for controlling current through an inductor, two input terminals to which an input voltage is coupled and two output terminals where the output DC power is provided, a pulse width modulated PFC controller for providing a boost function for controlling the duty cycle of said switch, comprising:

a detection circuit for detecting said input voltage instantaneously such that a real time sample of said input voltage is detected;
and
a comparator circuit for comparing said real time input voltage sample and said output voltage;
said comparator circuit having an output coupled to said PFC controller such that the boost function of the PFC controller is controlled as a function of said comparator circuit output;
wherein the boost function is inhibited so long as said real time input yoltage sample exceeds said output voltage and said boost function is enabled as soon as said real time input voltage sample is less than the output voltage.

2 more elements

In a system having a boost converter comprising an inductor, a capacitor and a switch, said boost converter having two input terminals to which a rectified input voltage is coupled and two output terminals where the output DC voltage is provided, said switch having a control input and being controlled such that when said switch is open, current through said inductor is maintained by a path provided by said switch, and having a pulse width modulator (PWM) providing power factor correction (PFC) and having at least one control input and an output designed to provide control of the state of said switch;

a control circuit coupled between one of said control inputs of said PWM and said input and output terminals of said boost converter for controlling said PWM, comprising:
a detection circuit for detecting said rectified input voltage instantaneously such that a real time sample of said input voltage is detected;
and
a comparator circuit for comparing said real time input voltage sample and a feedback signal indicative of said output DC voltage to said output of said detection circuit;
said comparator circuit outputs a control signal to said PWM such that the boost function of the PWM is controlled as a function of the output of said comparator circuit;
wherein the boost function is inhibited so long as said real time input voltage sample exceeds said output voltage and said boost function is enabled as soon as said real time input voltage sample is less than the output voltage such that said boost function is reenabled more quickly after a power line disturbance conditions affecting the input voltage.

3 more elements

Dependencies are inferred from the claim text.

Real-time voltage detection and protection circuit for PFC boost converters

Life of this patent

Real-time voltage detection and protection circuit for PFC boost converters

Life of this patent

Abstract

Claims16