AC-DC converter

• US 10,530,269 B2
• Filed: 06/27/2019
• Issued: 01/07/2020
• Est. Priority Date: 01/06/2017
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Hashimoto, Takao, Ishii, Takuya
• Primary Examiner(s): Berhane, Adolf D
• Assistant Examiner(s): Demisse, Afework S
• Application Number:
  US16/455,623
• Publication Number:
  US 20190326829A1
• Time in Patent Office: 194 Days
• CPC Class Codes: H02M 1/0085 Partially controlled bridges
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 1/4208 Arrangements for improving power factor of AC input
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 1/4233 using a bridge converter comprising active switches
• CPC Class Codes: H02M 7/062 Avoiding or suppressing excessive transient voltages or currents
• CPC Class Codes: H02M 7/217 using semiconductor devices only
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

An alternating current-direct current (AC-DC) converter includes: an input AC power supply that outputs an input AC voltage; a step-up converter that converts the input AC voltage into an output DC voltage to be outputted from an output capacitor; and an inrush current suppressing circuit. The inrush current suppressing circuit includes: an inrush current suppressing resistor provided on a path through which a current from the input AC power supply flows to charge the output capacitor and returns to the input AC power supply; a resistance short-circuiting switch that short-circuits the inrush current suppressing resistor; and a control circuit that generates a signal for turning off the resistance short-circuiting switch when an absolute value of the input AC voltage is higher than the output DC voltage.

Claims

1. An alternating current-direct current (AC-DC) converter comprising:

an input AC power supply that outputs an input AC voltage;

a step-up converter that converts the input AC voltage into an output DC voltage and outputs the output DC voltage from an output capacitor; and

an inrush current suppressing circuit,

the inrush current suppressing circuit including;

an inrush current suppressing resistor provided on a path through which a current from the input AC power supply flows to charge the output capacitor of the step-up converter and returns to the input AC power supply;

a resistance short-circuiting switch that short-circuits the inrush current suppressing resistor; and

a control circuit that generates a signal for turning off the resistance short-circuiting switch when an absolute value of the input AC voltage is higher than the output DC voltage.

2. The AC-DC converter according to claim 1,

wherein the step-up converter includes:

a full-wave rectifying circuit that full-wave rectifies the input AC voltage;

a series circuit of an inductor and a step-up switch, the series circuit being connected in parallel with an output of the full-wave rectifying circuit;

a rectifying/smoothing circuit including a rectifier and the output capacitor, the rectifier rectifying and smoothing a voltage across the step-up switch; and

a control drive circuit that controls driving of the step-up switch, and

the control circuit generates the signal for turning off the resistance short-circuiting switch when an input rectified voltage output from the full-wave rectifying circuit is higher than the output DC voltage.

3. The AC-DC converter according to claim 2,

wherein the control circuit includes:

an output detection circuit that divides or level-shifts the output DC voltage and then outputs an output detection voltage;

an input detection circuit that divides or level-shifts the input rectified voltage and then outputs an input detection voltage; and

a comparator that compares the output detection voltage and the input detection voltage, and

the control circuit turns off the resistance short-circuiting switch when a voltage difference between the output DC voltage and the input rectified voltage is equal to or smaller than a first reference value.

4. The AC-DC converter according to claim 1,

wherein the step-up converter includes:

a first input terminal that receives the input AC voltage from one end of the input AC power supply through an inductor;

a second input terminal that receives the input AC voltage from another end of the input AC power supply;

a first series circuit in which a high-side switch and a low-side switch are connected in series, the high-side switch and the low-side switch each being connected to the first input terminal;

a second series circuit in which a high-side rectifier and a low-side rectifier are connected in series, the high-side rectifier and the low-side rectifier each being connected to the second input terminal;

a control drive circuit that controls driving of the high-side switch and the low-side switch; and

the output capacitor connected in parallel with the first series circuit and the second series circuit, and

the control circuit generates a signal for turning on the resistance short-circuiting switch when the one end of the input AC power supply has a potential between a ground potential of the step-up converter and the output DC voltage.

5. The AC-DC converter according to claim 4,

wherein the control circuit includes:

an output detection circuit that divides or level-shifts the output DC voltage and then outputs an output detection voltage;

an input detection circuit that divides or level-shifts a potential of one end of the input AC power supply and then outputs an input detection voltage;

a first comparator that compares the input detection voltage and the ground potential of the step-up converter; and

a second comparator that compares the input detection voltage and the output detection voltage, and

the control circuit turns off the resistance short-circuiting switch when a voltage difference between the output DC voltage and the potential of the one end of the input AC power supply is equal to or smaller than a first reference value and a voltage difference between the output detection voltage and the ground potential of the step-up converter is equal to or smaller than the first reference value.

6. The AC-DC converter according to claim 1,

wherein the step-up converter includes:

a first input terminal that receives the input AC voltage from one end of the input AC power supply through a first inductor;

a second input terminal that receives the input AC voltage from another end of the input AC power supply through a second inductor;

a first series circuit in which a first high-side rectifier and a first switch are connected in series, the first high-side rectifier and the first switch being connected to the first input terminal;

a second series circuit in which a second high-side rectifier and a second switch are connected in series, the second high-side rectifier and the second switch being connected to the second input terminal;

a control drive circuit that controls driving of the first switch and the second switch;

the output capacitor connected in parallel with the first series circuit and the second series circuit;

a first low-side rectifier connected between a node between the first switch and the second switch and the one end of the input AC power supply; and

a second low-side rectifier connected between the node between the first switch and the second switch and the other end of the input AC power supply, and

the control circuit generates a signal for turning on the resistance short-circuiting switch when potentials of the one end and the other end of the input AC power supply are both lower than the output DC voltage.

7. The AC-DC converter according to claim 6,

wherein the control circuit includes:

an output detection circuit that divides or level-shifts the output DC voltage and then outputs an output detection voltage;

a first input detection circuit that divides or level-shifts a potential of one end of the input AC power supply and then outputs a first input detection voltage;

a second input detection circuit that divides or level-shifts a potential of another end of the input AC power supply and then outputs a second input detection voltage;

a first comparator that compares the output detection voltage and the first input detection voltage; and

a second comparator that compares the output detection voltage and the second input detection voltage, and

the control circuit turns off the resistance short-circuiting switch when a voltage difference between the output DC voltage and the potential of the one end of the input AC power supply is equal to or smaller than a first reference value and a voltage difference between the output detection voltage and the potential of the other end of the input AC power supply is equal to or smaller than the first reference value.