Power converter

Patent metadata

Field	Value
Publication number	US-10469064-B2
Application number	US-201816016896-A
Country	US
Kind code	B2
Filing date	Jun 25, 2018
Priority date	Aug 7, 2017
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

A signal converter circuit includes a frequency detection circuit configured to determine whether an external control signal is a PWM signal. A PWM frequency converter circuit is configured to detect, when a PWM signal is input, a duty cycle of the PWM signal and to generate a first digital signal. An AD converter is configured to generate a second digital signal based on an input DC voltage or a voltage attributable to a variable resistor to digital data using a maximum AD convertible input voltage as a duty cycle of 100%. An output signal generation circuit is configured to generate, based on the first or second digital signals output from the PWM frequency converter circuit or the AD converter, a PWM signal with a duty cycle based on that first or second digital signals.

First claim

What is claimed is:

1. A power converter comprising:
a signal converter circuit configured to receive an external control signal which is one of a pulse width modulation signal and a direct-current voltage, and to adjust a threshold used by a feedback circuit to detect an output voltage or electric current to be supplied to a load, wherein
the signal converter circuit includes
a frequency detection circuit configured to determine whether the external control signal is the pulse width modulation signal,
a pulse width modulation frequency converter circuit configured to detect a duty cycle of the pulse width modulation signal and to generate a first digital signal based on the detected duty cycle,
an analog-to-digital converter configured to generate a second digital signal based on a ratio of the direct-current voltage to a maximum analog-to-digital convertible input voltage,
a multiplexer configured to select the first digital signal when the frequency detection circuit determines that the external control signal is the pulse width modulation signal, and to select the second digital signal when the frequency detection circuit determines that the external control signal is not the pulse width modulation signal, and
an output signal generation circuit configured to generate as an output signal a first output pulse width modulation signal with a first duty cycle based on the first digital signal when the first digital signal is selected by the multiplexer and to generate as the output signal a second output pulse width modulation signal- with a second duty cycle based on the second digital signal when the second digital signal is selected by the multiplexer, and to supply the output signal to the feedback circuit, such that the output signal has the first duty cycle when the external control signal is the pulse width modulation signal, and has the second duty cycle when the external control signal is the direct current voltage.

2. A power converter comprising:
a signal converter circuit configured to receive an external control signal which is one of a pulse width modulation signal and a direct-current voltage, and to adjust a threshold used by a feedback circuit to detect an output voltage or electric current to be supplied to a load, wherein
the signal converter circuit includes
a frequency detection circuit configured to determine whether the external control signal is the pulse width modulation signal, the frequency detection circuit binarizing the external control signal and determining that the external control signal is in the form of the pulse width modulation signal when the binarized signal has a frequency higher than a predetermined frequency,
a pulse width modulation frequency converter circuit configured to detect a duty cycle of the pulse width modulation signal and to generate a first digital signal based on the detected duty cycle,
an analog-to-digital converter configured to generate a second digital signal based on a ratio of the direct-current voltage to a maximum analog-to-digital convertible input voltage,
a multiplexer configured to select the first digital signal when the frequency detection circuit determines that the external control signal is the pulse width modulation signal, and to select the second digital signal when the frequency detection circuit determines that the external control signal is not the pulse width modulation signal, and
an output signal generation circuit configured to generate as an output signal a first output pulse width modulation signal with a first duty cycle based on the first digital signal when the first digital signal is selected by the multiplexer and to generate as the output signal a second output pulse width modulation signal- with a second duty cycle based on the second digital signal when the second digital signal is selected by the multiplexer, and to supply the output signal to the feedback circuit.

3. A power converter comprising:
a signal converter circuit configured to receive an external control signal which is one of a pulse width modulation signal and a direct-current voltage, and to adjust a threshold used by a feedback circuit to detect an output voltage or electric current to be supplied to a load, wherein
the signal converter circuit includes
a frequency detection circuit configured to determine whether the external control signal is the pulse width modulation signal,
a pulse width modulation frequency converter circuit configured to detect a duty cycle of the pulse width modulation signal and to generate a first digital signal based on the detected duty cycle,
an analog-to-digital converter configured to generate a second digital signal based on a ratio of the direct-current voltage to a maximum analog-to-digital convertible input voltage,
a multiplexer configured to select the first digital signal when the frequency detection circuit determines that the external control signal is the pulse width modulation signal, and to select the second digital signal when the frequency detection circuit determines that the external control signal is not the pulse width modulation signal, and
an output signal generation circuit configured to generate as an output signal a first output pulse width modulation signal with a first duty cycle based on the first digital signal when the first digital signal is selected by the multiplexer and to generate as the output signal a second output pulse width modulation signal- with a second duty cycle based on the second digital signal when the second digital signal is selected by the multiplexer, and to supply the output signal to the feedback circuit the frequency detection circuit including
a hysteresis comparator configured to binarize the external control signal,
a flip-flop configured to be set by an output signal of the hysteresis comparator and reset by a signal obtained by delaying a reset signal with a predetermined frequency,
a frequency division circuit configured to divide a frequency of an output signal of the flip-flop, to be reset by a logical AND signal indicating a logical AND between the reset signal and an inverted output signal of the flip-flop, and to output a determination signal indicating that the external control signal is the pulse width modulation signal when the output signal of the flip-flop is counted a predetermined number of times without being reset, and
an AND circuit configured to inhibit, when the frequency division circuit outputs the determination signal, an input of the output signal of the flip-flop and to maintain the output of the determination signal.

4. A power converter comprising:
a signal converter circuit configured to receive an external control signal which is one of a pulse width modulation signal and a direct-current voltage, and to adjust a threshold used by a feedback circuit to detect an output voltage or electric current to be supplied to a load, wherein
the signal converter circuit includes
a frequency detection circuit configured to determine whether the external control signal is the pulse width modulation signal,
a pulse width modulation frequency converter circuit configured to detect a duty cycle of the pulse width modulation signal and to generate a first digital signal based on the detected duty cycle,
an analog-to-digital converter configured to generate a second digital signal based on a ratio of the direct-current voltage to a maximum analog-to-digital convertible input voltage,
a multiplexer configured to select the first digital signal when the frequency detection circuit determines that the external control signal is the pulse width modulation signal, and to select the second digital signal when the frequency detection circuit determines that the external control signal is not the pulse width modulation signal, and
an output signal generation ci

Assignees

• Fuji Electric Co Ltd

Inventors

• Yabuzaki Jun

Classifications

• H03K19/0175

  Coupling arrangements; Interface arrangements (interface arrangements for digital computers G06F3/00, G06F13/00) · CPC title

• H02M3/157

  with digital control · CPC title

• G06F3/05 Primary

  Digital input using the sampling of an analogue quantity at regular intervals of time {, input from a/d converter or output to d/a converter} · CPC title

• G01R19/252

  using analogue/digital converters of the type with conversion of voltage or current into frequency and measuring of this frequency · CPC title

• H03K7/08 Primary

  Duration or width modulation {; Duty cycle modulation} · CPC title