US 2009/0213629 A1Published application

Powering circuit of ac-dc converter

AssigneeMacroblock, Inc.

InventorsHsing-Fu LIU, Chin Sun, Chih-Yu Wu

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Abstract

A powering circuit of an AC-DC converter, for converting a high AC input voltage into a low DC output voltage to provide a load voltage in a stable DC bias range, includes a rectifier, a sensing circuit, a control switching circuit, and a voltage regulating capacitor. The rectifier has a primary side coupled to an AC power supply and a secondary side for outputting a DC power supply. The sensing circuit compares the AC input voltage with a preset reference voltage, and turns on a second switch in the control switching circuit when the AC input voltage is lower than the reference voltage, thereby providing a low DC output voltage. The control switching circuit sustains the DC output voltage in a stable DC bias range. Therefore, in addition to reducing the power consumption of the second switch, this circuit structure is simple and can achieve the purpose of circuit integration.

Claims20

Dependent claims

A powering circuit of an AC-DC converter, for converting a AC input voltage from an AC power supply into a DC output voltage, comprising:

a rectifier, having a primary side coupled to the AC power supply and a secondary side for outputting a DC power supply;
a sensing circuit, having a voltage divider and a first switch, wherein the first switch comprises a control pad, an input pad, and an output pad, the output pad is connected to ground potential, the voltage divider is coupled to the secondary side of the rectifier so as to obtain a divided DC voltage of the DC power supply at the secondary side and connect the divided DC voltage to the control pad of the first switch, for turning off the first switch when the divided DC voltage is lower than a turn-on voltage of the first switch;
a control switching circuit, having a third resistor, a first zener diode, and a second switch, wherein the second switch has a control pad, an input pad, and an output pad, the third resistor is connected at one end to the secondary side of the rectifier and at the other end to the input pad of the first switch and a cathode of the first zener diode, an anode of the first zener diode is connected to ground potential, the control pad of the second switch is connected to the input pad of the first switch and the cathode of the first zener diode, the input pad of the second switch is connected to the secondary side of the rectifier, and the output pad of the second switch is connected to a DC output end, for turning on the second switch when the DC voltage of the DC power supply at the secondary side of the rectifier is lower than a preset reference voltage, and turning off the second switch when the DC voltage of the DC power supply at the secondary side of the rectifier is higher than the preset reference voltage;
and
a voltage regulating capacitor, being connected at one end to the output pad of the second switch and the other end to ground potential.

2 more elements

An integrated powering circuit of an AC-DC converter fabricated in a semiconductor process, capable of converting a AC input voltage from an AC power supply into a DC output voltage, comprising:

a rectifier, having a primary side coupled to the AC power supply and a secondary side for outputting a DC power supply;
a sensing circuit, having a voltage divider and a first switch, wherein the first switch comprises a control pad, an input pad, and an output pad, the output pad is connected to ground potential, the voltage divider is coupled to the secondary side of the rectifier so as to obtain a divided DC voltage of the DC power supply at the secondary side and connect the divided DC voltage to the control pad of the first switch, for turning off the first switch when the divided DC voltage is lower than a turn-on voltage of the first switch;
a control switching circuit, having a third resistor, a first zener diode, and a second switch, wherein the second switch has a control pad, an input pad, and an output pad, the third resistor is connected at one end to the secondary side of the rectifier and at the other end to the input pad of the first switch and a cathode of the first zener diode, an anode of the first zener diode is connected to ground potential, the control pad of the second switch is connected to the input pad of the first switch and the cathode of the first zener diode, the input pad of the second switch is connected to the secondary side of the rectifier, and the output pad of the second switch is connected to a DC output end, for turning on the second switch when the DC voltage of the DC power supply at the secondary side of the rectifier is lower than a preset reference voltage, and turning off the second switch when the DC voltage of the DC power supply at the secondary side of the rectifier is higher than the preset reference voltage;
and
a voltage regulating capacitor, being connected at one end to the output pad of the second switch and at the other end to ground potential.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/098,512Filed 7 Apr 2008
Priority: TW 09710637422 Feb 2008
Published: 27 Aug 2009
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

H02M 3/155
Using devices of a triode or transistor type requiring continuous application of a control signal: using semiconductor devices only
H02M 7/155
Using devices of a thyratron or thyristor type requiring extinguishing means: using semiconductor devices only
H02M 7/2176
Using semiconductor devices only: comprising a passive stage to generate a rectified sinusoidal voltage and a controlled switching element in…
H02M
Apparatus for conversion between ac and ac, between ac and dc, or