System and method providing over current and over power protection for power converter

Patent metadata

Field	Value
Publication number	US-9647448-B2
Application number	US-201313900430-A
Country	US
Kind code	B2
Filing date	May 22, 2013
Priority date	Aug 18, 2005
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

System and method for protecting a power converter. A system includes a threshold generator configured to generate a threshold signal, and a first comparator configured to receive the threshold signal and a first signal and to generate a comparison signal. The first signal is associated with an input current for a power converter. Additionally, the system includes a pulse-width-modulation generator configured to receive the comparison signal and generate a modulation signal in response to the comparison signal, and a switch configured to receive the modulation signal and adjust the input current for the power converter. The threshold signal is associated with a threshold magnitude as a function of time. The threshold magnitude increases with time at a first slope during a first period, and the threshold magnitude increases with time at a second slope during a second period. The first slope and the second slope are different.

First claim

What is claimed is:

1. A system for protecting a power converter, the system comprising:
a voltage generator configured to generate a first voltage signal, the first voltage signal being associated with a first voltage magnitude;
a processing component including one or more comparators, the processing component configured to receive the first voltage signal and an input signal and to generate an output signal, the input signal being associated with an input current for the power converter; and
a pulse-width-modulation generator configured to receive the output signal, generate a modulation signal based on at least information associated with the output signal, and output the modulation signal to a switch to adjust the input current for the power converter;
wherein:
the processing component is further configured to generate the output signal in a first logic state in response to an input magnitude for the input signal being larger than an effective threshold magnitude, and to generate the output signal in a second logic state in response to the input magnitude being smaller than the effective threshold magnitude;
the first logic state and the second logic state are different;
the effective threshold magnitude remains constant during a first substantial period of time;
the effective threshold magnitude changes linearly with time at a slope during a second substantial period of time, the slope being not equal to zero;
the effective threshold magnitude remains constant during a third substantial period of time;
the processing component is further configured to receive a second voltage signal, the second voltage signal being associated with a second voltage magnitude; and
the effective threshold magnitude is equal to the second voltage magnitude during the third substantial period of time.

2. The system of claim 1 wherein:
one of the first logic state and the second logic state is associated with a logic high level; and
the other one of the first logic state and the second logic state is associated with a logic low level.

3. The system of claim 1 wherein the pulse-width-modulation generator is further configured to turn off the switch in response to the output signal being in the first logic state.

4. The system of claim 1 wherein the effective threshold magnitude is periodic with a threshold period, the threshold period including the first substantial period of time, the second substantial period of time, and the third substantial period of time.

5. The system of claim 1 wherein:
the power converter includes an inductive winding; and
the input current is configured to flow through the inductive winding.

6. The system of claim 1 , and further comprising a resistor configured to convert the input current for the power converter to a converted voltage, the converted voltage being the input signal.

7. The system of claim 1 wherein the effective threshold magnitude is equal to the first voltage magnitude during the second substantial period of time.

8. The system of claim 7 wherein the effective threshold magnitude is equal to the first voltage magnitude during the first substantial period of time.

9. A system for protecting a power converter, the system comprising:
a voltage generator configured to generate a first voltage signal, the first voltage signal being associated with a first voltage magnitude;
a processing component including one or more comparators, the processing component configured to receive the first voltage signal and an input signal and to generate an output signal, the input signal being associated with an input current for the power converter; and
a pulse-width-modulation generator configured to receive the output signal, generate a modulation signal based on at least information associated with the output signal, and output the modulation signal to a switch to adjust the input current for the power converter;
wherein:
the processing component is further configured to generate the output signal in a first logic state in response to an input magnitude for the input signal being larger than an effective threshold magnitude, and to generate the output signal in a second logic state in response to the input magnitude being smaller than the effective threshold magnitude;
the first logic state and the second logic state are different;
the effective threshold magnitude remains constant during a first substantial period of time;
the effective threshold magnitude changes linearly with time at a slope during a second substantial period of time, the slope being not equal to zero;
the effective threshold magnitude remains constant during a third substantial period of time;
the processing component includes a resistor configured to receive a first current and generate a second voltage based on at least information associated with the first current; and
the effective threshold magnitude is equal in magnitude to a sum of a predetermined threshold magnitude and the second voltage.

10. A system for protecting a power converter, the system comprising:
a voltage generator configured to generate a first voltage signal, the first voltage signal being associated with a first voltage magnitude;
a processing component including one or more comparators, the processing component configured to receive the first voltage signal and an input signal and to generate an output signal, the input signal being associated with an input current for the power converter; and
a pulse-width-modulation generator configured to receive the output signal, generate a modulation signal based on at least information associated with the output signal, and output the modulation signal to a switch to adjust the input current for the power converter;
wherein:
the processing component is further configured to generate the output signal in a first logic state in response to an input magnitude for the input signal being larger than an effective threshold magnitude, and to generate the output signal in a second logic state in response to the input magnitude being smaller than the effective threshold magnitude;
the first logic state and the second logic state are different;
the effective threshold magnitude remains constant during a first substantial period of time;
the effective threshold magnitude changes linearly with time at a slope during a second substantial period of time, the slope being not equal to zero;
the effective threshold magnitude remains constant during a third substantial period of time; and
the pulse-width-modulation generator is further configured to receive the input signal, generate the modulation signal based on at least information associated with the input signal and the output signal, and output the modulation signal to the switch to adjust the input current for the power converter.

11. A system for protecting a power converter, the system comprising:
a voltage generator configured to generate a first voltage signal, the first voltage signal being associated with a first voltage magnitude;
a processing component including one or more comparators, the processing component configured to receive the first voltage signal and an input signal and to generate an output signal, the input signal being associated with an input current for the power converter; and
a pulse-width-modulation generator configured to receive the output signal, generate a modulation signal based on at least information associated with the output signal, and output the modulation signal to a switch to adjust the input current for the power converter;
wherein:
the processing component is further configured to generate the output signal in a first logic state in response to an input magnitude f

Assignees

• On Bright Electronics Shanghai Co Ltd

Inventors

• Fang Lieyi
• Zhao Shifeng
• Li Bo
• Chen Zhiliang

Classifications

• H02H7/12 Primary

  for static converters or rectifiers {(for discharge lamp power supplies using static converters H05B41/2851, H05B41/2921, H05B41/2981)} · CPC title

• H02H7/1203 Primary

  Circuits independent of the type of conversion · CPC title