US 10,630,188 B2Granted

Switching power supply apparatus and semiconductor device

AssigneePanasonic Intellectual Property Management Co., Ltd.

InventorsKensuke Takahashi, Takashi Saji

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Abstract

A switching power supply apparatus includes a PFM control circuit that outputs a clock signal Set such that a switching frequency of a switching element varies in accordance with a load state. The clock signal Set determines a turn-on timing of the switching element. A reference value of a current flowing through the switching element determines a turn-off timing of the switching element. A modulation signal is applied to the turn-off timing of the switching element to modulate one of a peak value of a drain current flowing through the switching element and an on-time of the switching element. Input control is performed separately on the clock signal Set and the modulation signal. Accordingly, even when the clock signal Set and the modulation signal contribute to each other to offset each other, modulation effects are not cancelled.

Claims13

Dependent claims

A switching power supply apparatus comprising:

a transformer that includes a primary coil and a secondary coil;
a switching element that is connected in series with the primary coil;
a control circuit configured to control a switching operation of the switching element to perform switching control on a first DC voltage that is input to the switching element via the primary coil;
an output voltage generation circuit configured to convert an AC voltage induced in the secondary coil to a second DC voltage, and supply an output current to a load;
and
an output state detection circuit configured to output a feedback signal in accordance with the second DC voltage of the secondary coil or the output current of the secondary coil, wherein:
the control circuit includes:
a turn-on signal generation circuit configured to generate a turn-on signal of the switching element, the turn-on signal being cyclic pulse signals, an oscillation frequency of which is adjusted, when the cyclic pulse signals are output, in accordance with the feedback signal such that the second DC voltage or the output current is constant;
and
a turn-off signal generation circuit configured to generate a turn-off signal of the switching element, the turn-off signal generation circuit being electrically disconnected from the feedback signal,
the turn-off signal generation circuit includes:
a current detection circuit configured to detect a current flowing through the switching element and output a detection value corresponding to the current;
a modulation signal generation circuit configured to generate a modulation signal that is a periodic signal;
and
a timing modulation circuit configured to modulate a generation timing of the turn-off signal in accordance with the modulation signal,
the timing modulation circuit includes a comparator, and a reference value is input to one of input terminals of the comparator,
the detection value output from the current detection circuit is input to another of the input terminals of the comparator, and
the reference value is modulated in accordance with the modulation signal.

15 more elements

A switching power supply apparatus comprising:

a transformer that includes a primary coil and a secondary coil;
a switching element that is connected in series with the primary coil;
a control circuit configured to control a switching operation of the switching element to perform switching control on a first DC voltage that is input to the switching element via the primary coil;
an output voltage generation circuit configured to convert an AC voltage induced in the secondary coil to a second DC voltage, and supply an output current to a load;
and
an output state detection circuit configured to output a feedback signal in accordance with the second DC voltage of the secondary coil or the output current of the secondary coil, wherein:
the control circuit includes:
a turn-on signal generation circuit configured to generate a turn-on signal of the switching element, the turn-on signal generation circuit including an oscillator configured to generate, as the turn-on signal, cyclic pulse signals having an oscillation frequency which is adjusted in accordance with the feedback signal such that the second DC voltage or the output current is constant;
and
a turn-off signal generation circuit configured to generate a turn-off signal of the switching element, the turn-off signal generation circuit being electrically disconnected from the feedback signal,
the turn-off signal generation circuit includes:
a current detection circuit configured to detect a current flowing through the switching element and output a detection value corresponding to the current;
a modulation signal generation circuit configured to generate a modulation signal that is a periodic signal;
and
a timing modulation circuit configured to modulate a generation timing of the turn-off signal in accordance with the modulation signal,
the timing modulation circuit includes a comparator, and a reference value is input to one of input terminals of the comparator,
the detection value output from the current detection circuit is input to another of the input terminals of the comparator, and
the reference value is modulated in accordance with the modulation signal.

15 more elements

A switching power supply apparatus comprising:

a transformer that includes a primary coil and a secondary coil;
a switching element that is connected in series with the primary coil;
a control circuit configured to control a switching operation of the switching element to perform switching control on a first DC voltage that is input to the switching element via the primary coil;
an output voltage generation circuit configured to convert an AC voltage induced in the secondary coil to a second DC voltage, and supply an output current to a load;
and
an output state detection circuit configured to output a feedback signal in accordance with the second DC voltage of the secondary coil or the output current of the secondary coil, wherein:
the control circuit includes:
a turn-on signal generation circuit configured to generate a turn-on signal of the switching element, the turn-on signal being cyclic pulse signals, an oscillation frequency of which is adjusted, when the cyclic pulse signals are output, in accordance with the feedback signal such that the second DC voltage or the output current is constant;
and
a turn-off signal generation circuit configured to generate a turn-off signal of the switching element, the turn-off signal generation circuit being electrically disconnected from the feedback signal,
the turn-off signal generation circuit includes:
a current detection circuit configured to detect a current flowing through the switching element and output a detection value corresponding to the current;
a modulation signal generation circuit configured to generate a modulation signal that is a periodic signal;
and
a timing modulation circuit configured to modulate a generation timing of the turn-off signal in accordance with the modulation signal,
the timing modulation circuit includes a comparator, and a reference value is input to one of input terminals of the comparator,
the detection value output from the current detection circuit is input to another of the input terminals of the comparator, and
the detection value is modulated in accordance with the modulation signal.

15 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/257,781Filed 25 Jan 2019 · continuation
Priority: JP 2011-25890828 Nov 2011
Published: US 2019/0173386 A16 Jun 2019
Granted: 21 Apr 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

H02M 3/33546
Of the forward type: with automatic control of the output voltage or current
H02M 3/33507
Using semiconductor devices only: with automatic control of the output voltage or current, e.g. flyback converters
H02M 3/33515
With automatic control of the output voltage or current, e.g. flyback converters: with digital control
H02M 3/33576
Having several active switching elements: having at least one active switching element at the secondary side of an isolation transformer

Family

PCT/JP2012/004676Parent of this continuation · filed 24 Jul 2012
Application14/275,348Parent of this continuation · filed 12 May 2014
Application15/595,606Parent of this continuation · filed 15 May 2017
US 9,685,871 B2Parent of this continuation · filed 20 Jun 2017
Application16/017,922Parent of this continuation · filed 25 Jun 2018
US 10,033,286 B2Parent of this continuation · filed 24 Jul 2018
US 2019/0173386 A1Pre-grant publication · published 6 Jun 2019
US 10,284,101 B2Parent of this continuation
US 2014/0328090 A1Published application
US 2017/0250616 A1Published application
US 2018/0301996 A1Published application
US 10,630,188 B2This patent

From the US filing history. Foreign family members aren’t listed.