Power converter controller with input current slope adjustment

Patent metadata

Field	Value
Publication number	US-2016134189-A1
Application number	US-201514665944-A
Country	US
Kind code	A1
Filing date	Mar 23, 2015
Priority date	Nov 7, 2014
Publication date	May 12, 2016
Grant date	—

Abstract

A transient event detector includes a first reference generator, an adjustable low-pass filter, and a comparator. The first reference generator coupled to scale the input current signal to generate a first reference current signal that tracks the input current signal. The adjustable low-pass filter circuit is coupled to receive the input current signal and to generate a filtered input current signal such that a magnitude of a slope of the filtered input current signal is less than the magnitude of the slope of the input current signal during a transient event. The first comparator is coupled to generate an event detection signal that indicates the presence of the transient event in response to a value of the filtered input current signal reaching a value of the first reference current signal. The adjustable low-pass filter circuit is configured to increase the cutoff frequency in response to the event detection signal.

First claim

What is claimed is:

1 . A transient event detector to detect whether a magnitude of a slope of an input current signal exceeds a slope threshold, the transient event detector comprising:
a first reference generator coupled to scale the input current signal to generate a first reference current signal that tracks the input current signal; an adjustable low-pass filter circuit coupled to receive the input current signal and to generate a filtered input current signal in response thereto, wherein the adjustable low-pass filter circuit has a cutoff frequency such that a magnitude of a slope of the filtered input current signal is less than the magnitude of the slope of the input current signal during a transient event; and a first comparator coupled to generate an event detection signal that indicates the presence of the transient event in response to a value of the filtered input current signal reaching a value of the first reference current signal, wherein the adjustable low-pass filter circuit is configured to increase the cutoff frequency in response to the event detection signal indicating the presence of the transient event to increase the magnitude of the slope of the filtered input current signal.

2 . The transient event detector of claim 1 , wherein the first reference generator is coupled to generate the first reference current signal that is greater than and tracks the input current signal, and wherein the first comparator generates the event detection signal in response to the filtered input current signal exceeding the first reference current signal.

3 . The transient event detector of claim 2 , wherein the first reference generator comprises a first current amplifier having a gain greater than one coupled to receive the input current signal and to generate the first reference current signal that is greater than and tracks the input current signal.

4 . The transient event detector of claim 2 , further comprising:
a second reference generator coupled to scale the input current signal to generate a second reference current signal that is less than and tracks the input current signal; and a second comparator coupled to compare the input current signal with the second reference current signal, wherein the adjustable low-pass filter circuit is further configured to increase the cutoff frequency in response to the second comparator indicating that the filtered input current signal is less than the second reference current signal.

5 . The transient event detector of claim 4 , wherein the second reference generator comprises a second current amplifier having a gain less than one coupled to receive the input current signal and to generate the second reference current signal that is less than and tracks the input current signal.

6 . The transient event detector of claim 1 , wherein the first comparator comprises:
a logic gate coupled to generate the event detection signal having logic states; and a first node coupled to an input of the logic gate and coupled to receive the filtered input current signal and the first reference current signal such that a voltage level at the first node reaches a threshold voltage level to change a logic state of event detection signal in response to the filtered input current signal exceeding the first reference current signal.

7 . The transient event detector of claim 1 , wherein the adjustable low-pass filter circuit comprises a resistor-capacitor (RC) network coupled to receive the input current signal and to generate the filtered input current signal in response thereto, and wherein the adjustable low-pass filter circuit is configured to adjust a value of at least one component included in the RC network to increase the cutoff frequency when the event detection signal indicates the presence of the transient event.

8 . The transient event detector of claim 7 , wherein the adjustable low-pass filter circuit further includes a switch coupled to decrease a resistance value of the at least one component included in the RC network to increase the cutoff frequency in response to the event detection signal.

9 . An input control circuit for use in a controller of a power converter that includes a variable current circuit coupled to conduct a variable current between input terminals of the power converter, the input control circuit comprising:
a current source coupled to selectively provide an analog current signal to the variable current circuit in response to an enable signal; and a transient event detector coupled to receive an input current signal representative of a current that is input to the input terminals of the power converter and to generate the enable signal in response to a magnitude of a slope of the input current signal exceeding a slope threshold, wherein the variable current circuit is configured to increase the variable current in response to the analog current signal to reduce the magnitude of the slope of the input current signal.

10 . The input control circuit of claim 9 , wherein the transient event detector comprises:
a first reference generator coupled to scale the input current signal to generate a first reference current signal that tracks the input current signal; an adjustable low-pass filter circuit coupled to receive the input current signal and to generate a filtered input current signal in response thereto, wherein the adjustable low-pass filter circuit has a cutoff frequency such that a magnitude of a slope of the filtered input current signal is less than the magnitude of the slope of the input current signal during a transient event; and a first comparator coupled to generate the enable signal in response to a value of the filtered input current signal reaching a value of the first reference current signal, wherein the adjustable low-pass filter circuit is configured to increase the cutoff frequency in response to the enable signal to increase the magnitude of the slope of the filtered input current signal.

11 . The input control circuit of claim 10 , wherein the first reference generator is coupled to generate the first reference current signal that is greater than and tracks the input current signal, and wherein the first comparator generates an event detection signal in response to the filtered input current signal exceeding the first reference current signal.

12 . The input control circuit of claim 11 , wherein the first reference generator comprises a first current amplifier having a gain greater than one coupled to receive the input current signal and to generate the first reference current signal that is greater than and tracks the input current signal.

13 . The input control circuit of claim 11 , wherein the transient event detector further comprises:
a second reference generator coupled to scale the input current signal to generate a second reference current signal that is less than and tracks the input current signal; and a second comparator coupled to compare the input current signal with the second reference current signal, wherein the adjustable low-pass filter circuit is further configured to increase the cutoff frequency in response to the second comparator indicating that the filtered input current signal is less than the second reference current signal.

14 . The input control circuit of claim 13 , wherein the second reference generator comprises a second current amplifier having a gain less than one coupled to receive the input current signal and to generate the second reference current signal that is less than and tracks the input current signal.

15 . The input control circuit of claim 10 , wherein the firs

Assignees

• Power Integrations Inc

Inventors

• Pregitzer Ricardo Luis Janezic
• Mao Mingming
• Pastore Tiziano
• Zhang Michael Yue
• Gaknoki Yury

Classifications

• H05B45/3575

  by means of dummy loads or bleeder circuits, e.g. for dimmers · CPC title

• H05B39/044

  continuously (H05B39/042 takes precedence) · CPC title

• H02M3/157 Primary

  with digital control · CPC title

• H02M2001/0009

  Electricity · mapped topic

• H02M1/0009

  Devices or circuits for detecting current in a converter · CPC title