ADAPTER POWER SUPPLY

• US 20100020578A1
• Filed: 10/07/2008
• Published: 01/28/2010
• Est. Priority Date: 07/25/2008
• Status: Active Grant

• Current Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group), Solum Co., Ltd.
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Oh, Dong Seong, Kim, Jong Sun, Moon, Gun Woo, Ryu, Byoung Woo, Choi, Seong Wook
• Granted Patent: US 8,027,174 B2
• Time in Patent Office: Days
• US Class Current: 363/68
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• 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 advantage of the present invention is to provide an adapter power supply which varies a link voltage of DC power serving an input power of a DC/DC converter according to variation of a load current estimated by measuring a secondary current using a lossless current measurement technique at a primary terminal of a transformer of the DC/DC converter and thus presuming a load current of an output power.

An adapter power supply according to present invention may include an AC/DC converter converting a commercial AC power into a DC power; a DC/DC converter including a transformer composed of a primary terminal and a secondary terminal in order to output an output power by converting a link voltage of the DC power; and a controller presuming a load current of the output power through a primary current of the transformer and varying the link voltage of the DC power according to variation of the estimated load current.

Claims

1. An adapter power supply comprising:

an AC/DC converter converting a commercial AC power into a DC power;

a DC/DC converter including a transformer composed of a primary terminal and a secondary terminal in order to output an output power by converting a link voltage of the DC power; and

a controller presuming a load current of the output power through a primary current of the transformer and varying the link voltage of the DC power according to variation of the estimated load current.

2. The adapter power supply according to claim 1, wherein the AC/DC converter includes:

a filter removing electromagnetic interference of the commercial AC power;

a rectifier rectifying and smoothing the AC power passing the filter; and

a power factor compensator compensating for a power factor of the rectified power passing the rectifier and outputting the DC power.

3. The adapter power supply according to claim 1, wherein the DC/DC converter is an LLC (Logical Link Control) resonant converter.

4. The adapter power supply according to claim 1, wherein the controller includes:

a first coupler outputting a difference between an output voltage of the output power and a reference output voltage;

a gain controller connected to the first coupler;

an Opto coupler connected to the gain controller;

a current sensor sensing the primary current of the transformer;

a variation controller connected to the current sensor, and outputting an output voltage control signal and a link voltage control signal;

a second coupler coupling a control signal passing the Opto coupler with the output voltage control signal outputted from the variation controller;

an integral controller connected to the second coupler;

a frequency modulator connected to the integral controller and controlling switching of the DC/DC converter;

a third coupler coupling a difference of the link voltage of the DC power and a reference link voltage, and the link voltage control signal of the variation controller;

a gain/integral controller connected to the third coupler; and

a pulse width modulator connected to the gain/integral controller and controlling switching of the AC/DC converter.

5. The adapter power supply according to claim 4, wherein the current sensor senses the primary current of the transformer through voltage ripple measurement of a resonant capacitor in which a voltage is varied by integrating a current of a resonant inductor at the primary terminal of the transformer.

6. The adapter power supply according to claim 4, wherein the current sensor senses the primary current of the transformer by a current distributing method using a part of a current inputted into the resonant capacitor at the primary terminal of the transformer.

7. The adapter power supply according to claim 4, wherein the current sensor senses the primary current of the transformer by adding an auxiliary winding to the resonant inductor at the primary terminal of the transformer.