CIRCUIT FOR DISCHARGING AC POWER

• US 20120134185A1
• Filed: 03/01/2011
• Published: 05/31/2012
• Est. Priority Date: 11/30/2010
• Status: Active Grant

• Current Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: SHIN, Yun Seop, Lee, Ki Eun
• Granted Patent: US 8,259,475 B2
• Time in Patent Office: Days
• US Class Current: 363/44
• CPC Class Codes: H02M 1/0048 Circuits or arrangements for reducing losses using snubbers H02M1/34
• CPC Class Codes: H02M 1/322 Means for rapidly discharging a capacitor of the converter for protecting electrical components or for preventing electrical shock
• CPC Class Codes: H02M 7/46 using discharge tubes without control electrode or semiconductor devices without control electrode
• 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

There is provided a circuit for discharging AC power including: a first rectifier rectifying AC power inputted from an AC power line; an electro-magnetic interference (EMI) removing unit installed between the AC power line and the first rectifier to suppress EMI of the AC power; a discharging signal generator generating a discharging signal from the AC power; and a discharging unit including a discharging resistor for discharging a voltage charged in the EMI removing unit according to the discharging signal, whereby standby power consumption may be reduced when the AC power is inputted and the voltage charged in a capacitor for removing EMI may be discharged to meet a predetermined safety standard when the AC power is blocked.

Claims

1. A power supply circuit having AC power discharging functions, the circuit comprising:

a first rectifier rectifying AC power inputted from an AC power line;

an electro-magnetic interference (EMI) removing unit installed between the AC power line and the first rectifier to suppress EMI of the AC power;

a discharging signal generator generating a discharging signal from the AC power; and

a discharging unit including a discharging resistor for discharging a voltage charged in the EMI removing unit according to the discharging signal

wherein the discharging resistor is connected between an output terminal of the first rectifier and a ground,

the discharging signal is generated from a ripple component of a rectified waveform, in which a magnitude of the AC power is reduced, and

the discharging signal generator includes;

a second rectifier generating the rectified waveform in which the magnitude of the AC power is reduced;

a blocking apacitor allowing only an AC component of the recitified waveform to pass therethrough; and

a third rectifier rectifying a ripple component of the AC component to generate the

5. The circuit of claim 1, wherein the second rectifier includes:

a first diode having an anode connected to a first line of the AC power line;

a first resistor having one end connected to a cathode of the first diode;

a second diode having an anode connected to a second line of the AC power line;

a second resistor having one end connected to a cathode of the second diode; and

a second capacitor having one end connected to the other ends of the first and second resistors and the other end connected to the ground.

6. The circuit of claim 1, wherein the third rectifier includes:

a third diode having a cathode connected to the blocking capacitor and an anode connected to the ground;

a fourth diode having an anode connected to the blocking capacitor; and

a third capacitor having one end connected to a cathode of the fourth diode and the other end connected to the ground.

7. The circuit of claim 6, wherein the discharging unit includes:

a first transistor having a base connected to one end of the third capacitor and an emitter connected to the ground;

a second transistor having a base connected to a collector of the first transistor, an emitter connected to the ground, and a collector connected to a standby power supply through a pull-up resistor; and

a fourth capacitor connected between the base of the second transistor and the ground.

8. The circuit of claim 1, wherein the first rectifier includes a bridge rectifier circuit configured of four diodes.

9. The circuit of claim 1, wherein the EMI removing unit includes an X-CAP installed in a line-to-line scheme.

2-4. -4. (canceled)

10. A power supply circuit having AC power discharging functions, the circuit comprising:

a first rectifier including a bridge rectifier circuit rectifying AC power inputted from an AC power line;

a first capacitor installed in a line-to-line scheme between the AC power line and the first rectifier to suppress electro-magnetic interference (EMI) of the AC power;

a discharging signal generator including a second rectifier generating a rectified waveform in which a magnitude of the AC power is reduced, a blocking capacitor allowing only an AC component of the rectified waveform to pass therethrough, and a third rectifier rectifying a ripple component of the AC component to generate a discharging signal; and

a discharging unit discharging a voltage charged in the first capacitor through a discharging resistor connected between an output terminal of the first rectifier and a ground according to the discharging signal.

11. The circuit of claim 10, wherein the second rectifier includes:

a first diode having an anode connected to a first line of the AC power line;

a first resistor having one end connected to a cathode of the first diode;

a second diode having an anode connected to a second line of the AC power line;

a second resistor having one end connected to a cathode of the second diode; and

a second capacitor having one end connected to the other ends of the first and second resistors and the other end connected to the ground.

12. The circuit of claim 11, wherein the third rectifier includes:

a third diode having a cathode connected to the blocking capacitor and an anode connected to the ground;

a fourth diode having an anode connected to the blocking capacitor; and

a third capacitor having one end connected to a cathode of the fourth diode and the other end connected to the ground.